1
|
Sibeaux A, Newport C, Green JP, Karlsson C, Engelmann J, Burt de Perera T. Taking a shortcut: what mechanisms do fish use? Commun Biol 2024; 7:578. [PMID: 38755224 PMCID: PMC11099040 DOI: 10.1038/s42003-024-06179-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 04/10/2024] [Indexed: 05/18/2024] Open
Abstract
Path integration is a powerful navigational mechanism whereby individuals continuously update their distance and angular vector of movement to calculate their position in relation to their departure location, allowing them to return along the most direct route even across unfamiliar terrain. While path integration has been investigated in several terrestrial animals, it has never been demonstrated in aquatic vertebrates, where movement occurs through volumetric space and sensory cues available for navigation are likely to differ substantially from those in terrestrial environments. By performing displacement experiments with Lamprologus ocellatus, we show evidence consistent with fish using path integration to navigate alongside other mechanisms (allothetic place cues and route recapitulation). These results indicate that the use of path integration is likely to be deeply rooted within the vertebrate phylogeny irrespective of the environment, and suggests that fish may possess a spatial encoding system that parallels that of mammals.
Collapse
Affiliation(s)
- Adelaide Sibeaux
- Department of Biology, University of Oxford, Zoology Research and Administration Building, 11a Mansfield Road, Oxford, OX1 3SZ, UK.
| | - Cait Newport
- Department of Biology, University of Oxford, Zoology Research and Administration Building, 11a Mansfield Road, Oxford, OX1 3SZ, UK
| | - Jonathan P Green
- Department of Biology, University of Oxford, Zoology Research and Administration Building, 11a Mansfield Road, Oxford, OX1 3SZ, UK
| | - Cecilia Karlsson
- Wolfson College, University of Cambridge, Cambridge, CB3 9BB, UK
| | - Jacob Engelmann
- Faculty of Biology, Bielefeld University, Universitätstrasse 25, Bielefeld, 33615, Germany
| | - Theresa Burt de Perera
- Department of Biology, University of Oxford, Zoology Research and Administration Building, 11a Mansfield Road, Oxford, OX1 3SZ, UK
| |
Collapse
|
2
|
Romanova N, Utvenko G, Prokshina A, Cellarius F, Fedorishcheva A, Pakhomov A. Migratory birds are able to choose the appropriate migratory direction under dim yellow narrowband light. Proc Biol Sci 2023; 290:20232499. [PMID: 38113940 PMCID: PMC10730290 DOI: 10.1098/rspb.2023.2499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 11/21/2023] [Indexed: 12/21/2023] Open
Abstract
Currently, it is generally assumed that migratory birds are oriented in the appropriate migratory direction under UV, blue and green light (short-wavelength) and are unable to use their magnetic compass in total darkness and under yellow and red light (long-wavelength). However, it has also been suggested that the magnetic compass has two sensitivity peaks: in the short and long wavelengths, but with different intensities. In this project, we aimed to study the orientation of long-distance migrants, pied flycatchers (Ficedula hypoleuca), under different narrowband light conditions during autumn and spring migrations. The birds were tested in the natural magnetic field (NMF) and a changed magnetic field (CMF) rotated counterclockwise by 120° under dim green (autumn) and yellow (spring and autumn) light, which are on the 'threshold' between the short-wavelength and long-wavelength light. We showed that pied flycatchers (i) were completely disoriented under green light both in the NMF and CMF but (ii) showed the migratory direction in the NMF and the appropriate response to CMF under yellow light. Our data contradict the results of previous experiments under narrowband green and yellow light and raise doubts about the existence of only short-wavelength magnetoreception. The parameters of natural light change dramatically in spectral composition and intensity after local sunset, and the avian magnetic compass should be adapted to function properly under such constantly changing light conditions.
Collapse
Affiliation(s)
- Nadezhda Romanova
- Moscow State Pedagogical University, 1/1 M. Pirogovskaya St., Moscow 119991, Russia
| | - Gleb Utvenko
- Department of Vertebrate Zoology, St. Petersburg State University, 199034 St. Petersburg, Russia
- Biological Station Rybachy, Zoological Institute RAS, Kaliningrad Region, Rybachy 238535, Russia
| | - Anisia Prokshina
- Department of Vertebrate Zoology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Fyodor Cellarius
- Department of Vertebrate Zoology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | | | - Alexander Pakhomov
- Biological Station Rybachy, Zoological Institute RAS, Kaliningrad Region, Rybachy 238535, Russia
| |
Collapse
|
3
|
Schneider WT, Holland RA, Keišs O, Lindecke O. Migratory bats are sensitive to magnetic inclination changes during the compass calibration period. Biol Lett 2023; 19:20230181. [PMID: 38016643 PMCID: PMC10684344 DOI: 10.1098/rsbl.2023.0181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 11/07/2023] [Indexed: 11/30/2023] Open
Abstract
The Earth's magnetic field is used as a navigational cue by many animals. For mammals, however, there are few data to show that navigation ability relies on sensing the natural magnetic field. In night-time migrating bats, experiments demonstrating a role for the solar azimuth at sunset in the calibration of the orientation system suggest that the magnetic field is a candidate for their compass. Here, we investigated how an altered magnetic field at sunset changes the nocturnal orientation of the bat Pipistrellus pygmaeus. We exposed bats to either the natural magnetic field, a horizontally shifted field (120°), or the same shifted field combined with a reversal of the natural value of inclination (70° to -70°). We later released the bats and found that the take-off orientation differed among all treatments. Bats that were exposed to the 120° shift were unimodally oriented northwards in contrast to controls which exhibited a bimodal north-south distribution. Surprisingly, the orientation of bats exposed to both a 120° shift and reverse inclination was indistinguishable from a uniform distribution. These results suggest that these migratory bats calibrate the magnetic field at sunset, and for the first time, they show that bats are sensitive to the angle of magnetic inclination.
Collapse
Affiliation(s)
| | - Richard A. Holland
- School of Natural Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK
| | - Oskars Keišs
- Laboratory of Ornithology, Institute of Biology, University of Latvia, Rīga LV–1004, Latvia
| | - Oliver Lindecke
- School of Natural Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK
- Institute of Biology and Environmental Sciences, Carl-von-Ossietzky Universität Oldenburg, Oldenburg 26129, Germany
| |
Collapse
|
4
|
Quinlan PD, Katz PS. State-dependent, visually guided behaviors in the nudibranch Berghia stephanieae. J Exp Biol 2023; 226:jeb245213. [PMID: 37661725 PMCID: PMC10560555 DOI: 10.1242/jeb.245213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 08/22/2023] [Indexed: 09/05/2023]
Abstract
Nudibranch mollusks have structurally simple eyes whose behavioral roles have not been established. We tested the effects of visual stimuli on the behavior of the nudibranch Berghia stephanieae under different food and hunger conditions. In an arena that was half-shaded, animals spent most of their time in the dark, where they also decreased their speed and made more changes in heading. These behavioral differences between the light and dark were less evident in uniformly illuminated or darkened arenas, suggesting that they were not caused by the level of illumination. Berghia stephanieae responded to distant visual targets; animals approached a black stripe that was at least 15 deg wide on a white background. They did not approach a stripe that was lighter than the background but approached a stripe that was isoluminant with the background, suggesting the detection of spatial information. Animals traveled in convoluted paths in a featureless arena but straightened their paths when a visual target was present even if they did not approach it, suggesting that visual cues were used for navigation. Individuals were less responsive to visual stimuli when food deprived or in the presence of food odor. Thus, B. stephanieae exhibits visually guided behaviors that are influenced by odors and hunger state.
Collapse
Affiliation(s)
- Phoenix D. Quinlan
- Neuroscience and Behavior Graduate Program, University of Massachusetts Amherst, Amherst, MA 01003, USA
- Department of Biology, University of Massachusetts Amherst, 611 North Pleasant Street, Amherst, MA 01003, USA
| | - Paul S. Katz
- Neuroscience and Behavior Graduate Program, University of Massachusetts Amherst, Amherst, MA 01003, USA
- Department of Biology, University of Massachusetts Amherst, 611 North Pleasant Street, Amherst, MA 01003, USA
| |
Collapse
|
5
|
Wallace JRA, Dreyer D, Reber TMJ, Khaldy L, Mathews-Hunter B, Green K, Zeil J, Warrant E. Camera-based automated monitoring of flying insects in the wild (Camfi). II. flight behaviour and long-term population monitoring of migratory Bogong moths in Alpine Australia. FRONTIERS IN INSECT SCIENCE 2023; 3:1230501. [PMID: 38469465 PMCID: PMC10926487 DOI: 10.3389/finsc.2023.1230501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 08/21/2023] [Indexed: 03/13/2024]
Abstract
Introduction The Bogong moth Agrotis infusa is well known for its remarkable annual round-trip migration from its breeding grounds across eastern and southern Australia to its aestivation sites in the Australian Alps, to which it provides an important annual influx of nutrients. Over recent years, we have benefited from a growing understanding of the navigational abilities of the Bogong moth. Meanwhile, the population of Bogong moths has been shrinking. Recently, the ecologically and culturally important Bogong moth was listed as endangered by the IUCN Red List, and the establishment of a program for long-term monitoring of its population has been identified as critical for its conservation. Methods Here, we present the results of two years of monitoring of the Bogong moth population in the Australian Alps using recently developed methods for automated wildlife-camera monitoring of flying insects, named Camfi. While in the Alps, some moths emerge from the caves in the evening to undertake seemingly random flights, filling the air with densities in the dozens per cubic metre. The purpose of these flights is unknown, but they may serve an important role in Bogong moth navigation. Results We found that these evening flights occur throughout summer and are modulated by daily weather factors. We present a simple heuristic model of the arrival to and departure from aestivation sites by Bogong moths, and confirm results obtained from fox-scat surveys which found that aestivating Bogong moths occupy higher elevations as the summer progresses. Moreover, by placing cameras along two elevational transects below the summit of Mt. Kosciuszko, we found that evening flights were not random, but were systematically oriented in directions relative to the azimuth of the summit of the mountain. Finally, we present the first recorded observations of the impact of bushfire smoke on aestivating Bogong moths - a dramatic reduction in the size of a cluster of aestivating Bogong moths during the fire, and evidence of a large departure from the fire-affected area the day after the fire. Discussion Our results highlight the challenges of monitoring Bogong moths in the wild and support the continued use of automated camera-based methods for that purpose.
Collapse
Affiliation(s)
- Jesse Rudolf Amenuvegbe Wallace
- Research School of Biology, The Australian National University, Canberra, ACT, Australia
- National Collections & Marine Infrastructure, CSIRO, Parkville, VIC, Australia
| | - David Dreyer
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| | | | - Lana Khaldy
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| | | | - Ken Green
- College of Asia and the Pacific, The Australian National University, Canberra, ACT, Australia
| | - Jochen Zeil
- Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Eric Warrant
- Research School of Biology, The Australian National University, Canberra, ACT, Australia
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| |
Collapse
|
6
|
Jennelle CS, Walter WD, Crawford J, Rosenberry CS, Wallingford BD. Movement of white‐tailed deer in contrasting landscapes influences management of chronic wasting disease. J Wildl Manage 2022. [DOI: 10.1002/jwmg.22306] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Christopher S. Jennelle
- Minnesota Department of Natural Resources 5463 West Broadway Avenue Forest Lake MN 55025 USA
| | - W. David Walter
- U.S. Geological Survey, Pennsylvania Cooperative Fish and Wildlife Research Unit, 403 Forest Resources Building The Pennsylvania State University, University Park PA 16802 USA
| | - Joanne Crawford
- Minnesota Department of Natural Resources 2118 Campus Drive SE, Suite 100 Rochester MN 55904 USA
| | - Christopher S. Rosenberry
- Bureau of Wildlife Management Pennsylvania Game Commission 2001 Elmerton Avenue Harrisburg PA 17110 USA
| | - Bret D. Wallingford
- Bureau of Wildlife Management Pennsylvania Game Commission 2001 Elmerton Avenue Harrisburg PA 17110 USA
| |
Collapse
|
7
|
Morten JM, Burrell RA, Frayling TD, Hoodless AN, Thurston W, Hawkes LA. Variety in responses of wintering oystercatchers
Haematopus ostralegus
to near‐collapse of their prey in the Exe Estuary,
UK. Ecol Evol 2022; 12:e9526. [DOI: 10.1002/ece3.9526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 10/17/2022] [Accepted: 10/29/2022] [Indexed: 11/25/2022] Open
Affiliation(s)
- Joanne M. Morten
- College of Life and Environmental Sciences University of Exeter, Hatherly Laboratories Exeter UK
| | - Ryan A. Burrell
- Game and Wildlife Conservation Trust Hampshire UK
- Devon & Cornwall Wader Ringing Group Ilfracombe UK
| | - Tim D. Frayling
- Devon & Cornwall Wader Ringing Group Ilfracombe UK
- Natural England, Sterling House, Dix's Field Exeter UK
| | | | | | - Lucy A. Hawkes
- College of Life and Environmental Sciences University of Exeter, Hatherly Laboratories Exeter UK
| |
Collapse
|
8
|
Gilbertson MLJ, Ketz AC, Hunsaker M, Jarosinski D, Ellarson W, Walsh DP, Storm DJ, Turner WC. Agricultural land use shapes dispersal in white-tailed deer (Odocoileus virginianus). MOVEMENT ECOLOGY 2022; 10:43. [PMID: 36289549 PMCID: PMC9608933 DOI: 10.1186/s40462-022-00342-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 10/04/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND Dispersal is a fundamental process to animal population dynamics and gene flow. In white-tailed deer (WTD; Odocoileus virginianus), dispersal also presents an increasingly relevant risk for the spread of infectious diseases. Across their wide range, WTD dispersal is believed to be driven by a suite of landscape and host behavioral factors, but these can vary by region, season, and sex. Our objectives were to (1) identify dispersal events in Wisconsin WTD and determine drivers of dispersal rates and distances, and (2) determine how landscape features (e.g., rivers, roads) structure deer dispersal paths. METHODS We developed an algorithmic approach to detect dispersal events from GPS collar data for 590 juvenile, yearling, and adult WTD. We used statistical models to identify host and landscape drivers of dispersal rates and distances, including the role of agricultural land use, the traversability of the landscape, and potential interactions between deer. We then performed a step selection analysis to determine how landscape features such as agricultural land use, elevation, rivers, and roads affected deer dispersal paths. RESULTS Dispersal predominantly occurred in juvenile males, of which 64.2% dispersed, with dispersal events uncommon in other sex and age classes. Juvenile male dispersal probability was positively associated with the proportion of the natal range that was classified as agricultural land use, but only during the spring. Dispersal distances were typically short (median 5.77 km, range: 1.3-68.3 km), especially in the fall. Further, dispersal distances were positively associated with agricultural land use in potential dispersal paths but negatively associated with the number of proximate deer in the natal range. Lastly, we found that, during dispersal, juvenile males typically avoided agricultural land use but selected for areas near rivers and streams. CONCLUSION Land use-particularly agricultural-was a key driver of dispersal rates, distances, and paths in Wisconsin WTD. In addition, our results support the importance of deer social environments in shaping dispersal behavior. Our findings reinforce knowledge of dispersal ecology in WTD and how landscape factors-including major rivers, roads, and land-use patterns-structure host gene flow and potential pathogen transmission.
Collapse
Affiliation(s)
- Marie L J Gilbertson
- Wisconsin Cooperative Wildlife Research Unit, Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, 1630 Linden Dr, 53706, Madison, WI, USA.
| | - Alison C Ketz
- Wisconsin Cooperative Wildlife Research Unit, Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, 1630 Linden Dr, 53706, Madison, WI, USA
| | - Matthew Hunsaker
- Wisconsin Cooperative Wildlife Research Unit, Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, 1630 Linden Dr, 53706, Madison, WI, USA
| | - Dana Jarosinski
- Wisconsin Department of Natural Resources, 1500 N Johns St, 53533, Dodgeville, WI, USA
- Warnell School of Forestry and Natural Resources, University of Georgia, 180 E Green St, 30602, Athens, GA, USA
| | - Wesley Ellarson
- Wisconsin Department of Natural Resources, 1500 N Johns St, 53533, Dodgeville, WI, USA
| | - Daniel P Walsh
- U.S. Geological Survey, Montana Cooperative Wildlife Research Unit, University of Montana, 32 Campus Drive NS 205, 59812, Missoula, MT, USA
| | - Daniel J Storm
- Wisconsin Department of Natural Resources, 1300 West Clairemont Ave, 54701, Eau Claire, WI, USA
| | - Wendy C Turner
- U.S. Geological Survey, Wisconsin Cooperative Wildlife Research Unit, Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, 1630 Linden Dr, 53706, Madison, WI, USA
| |
Collapse
|
9
|
Espinasse B, Sturbois A, Basedow SL, Hélaouët P, Johns DG, Newton J, Trueman CN. Temporal dynamics in zooplankton δ13C and δ15N isoscapes for the North Atlantic Ocean: Decadal cycles, seasonality, and implications for predator ecology. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.986082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The limited amount of ecological data covering offshore parts of the ocean impedes our ability to understand and anticipate the impact of anthropogenic stressors on pelagic marine ecosystems. Isoscapes, i.e., spatial models of the distribution of stable isotope ratios, have been employed in the recent years to investigate spatio-temporal patterns in biogeochemical process and ecological responses. Development of isoscapes on the scale of ocean basins is hampered by access to suitable reference samples. Here we draw on archived material from long-running plankton survey initiatives, to build temporally explicit isoscape models for the North Atlantic Ocean (> 40°N). A total of 570 zooplankton samples were retrieved from Continuous Plankton Recorder archives and analysed for δ13C and δ15N values. Bayesian generalised additive models were developed to (1) model the relations between isotopic values and a set of predictors and (2) predict isotopic values for the whole of the study area. We produced yearly and seasonal isoscape models for the period 1998–2020. These are the first observation-based time-resolved C and N isoscapes developed at the scale of the North Atlantic Ocean. Drawing on the Stable Isotope Trajectory Analysis framework, we identify five isotopically distinct regions. We discuss the hydro-biogeochemical processes that likely explain theses modes, the differences in temporal dynamics (stability and cycles) and compare our results with previous bioregionalization efforts. Finally, we lay down the basis for using the isoscapes as a tool to define predator distributions and their interactions with the trophic environment. The isoscapes developed in this study have the potential to update our knowledge of marine predator ecology and therefore our capacity to improve their conservation in the future.
Collapse
|
10
|
Landler L, Ruxton GD, Malkemper EP. The multivariate analysis of variance as a powerful approach for circular data. MOVEMENT ECOLOGY 2022; 10:21. [PMID: 35478074 PMCID: PMC9044715 DOI: 10.1186/s40462-022-00323-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 04/02/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND A broad range of scientific studies involve taking measurements on a circular, rather than linear, scale (often variables related to times or orientations). For linear measures there is a well-established statistical toolkit based on linear modelling to explore the associations between this focal variable and potentially several explanatory factors and covariates. In contrast, statistical testing of circular data is much simpler, often involving either testing whether variation in the focal measurements departs from circular uniformity, or whether a single explanatory factor with two levels is supported. METHODS We use simulations and example data sets to investigate the usefulness of a MANOVA approach for circular data in comparison to commonly used statistical tests. RESULTS Here we demonstrate that a MANOVA approach based on the sines and cosines of the circular data is as powerful as the most-commonly used tests when testing deviation from a uniform distribution, while additionally offering extension to multi-factorial modelling that these conventional circular statistical tests do not. CONCLUSIONS The herein presented MANOVA approach offers a substantial broadening of the scientific questions that can be addressed statistically using circular data.
Collapse
Affiliation(s)
- Lukas Landler
- Institute of Zoology, University of Natural Resources and Life Sciences (BOKU), Gregor-Mendel-Straße 33, 1180, Vienna, Austria.
| | - Graeme D Ruxton
- School of Biology, University of St Andrews, St Andrews, KY16 9TH, UK
| | - E Pascal Malkemper
- Research Group Neurobiology of Magnetoreception, Max Planck Institute for Neurobiology of Behavior - caesar, Ludwig-Erhard-Allee 2, 53175, Bonn, Germany
- Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, 16521, Prague 6, Czech Republic
| |
Collapse
|
11
|
Linscott JA, Navedo JG, Clements SJ, Loghry JP, Ruiz J, Ballard BM, Weegman MD, Senner NR. Compensation for wind drift prevails for a shorebird on a long-distance, transoceanic flight. MOVEMENT ECOLOGY 2022; 10:11. [PMID: 35255994 PMCID: PMC8900403 DOI: 10.1186/s40462-022-00310-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 02/18/2022] [Indexed: 05/13/2023]
Abstract
BACKGROUND Conditions encountered en route can dramatically impact the energy that migratory species spend on movement. Migratory birds often manage energetic costs by adjusting their behavior in relation to wind conditions as they fly. Wind-influenced behaviors can offer insight into the relative importance of risk and resistance during migration, but to date, they have only been studied in a limited subset of avian species and flight types. We add to this understanding by examining in-flight behaviors over a days-long, barrier-crossing flight in a migratory shorebird. METHODS Using satellite tracking devices, we followed 25 Hudsonian godwits (Limosa haemastica) from 2019-2021 as they migrated northward across a largely transoceanic landscape extending > 7000 km from Chiloé Island, Chile to the northern coast of the Gulf of Mexico. We identified in-flight behaviors during this crossing by comparing directions of critical movement vectors and used mixed models to test whether the resulting patterns supported three classical predictions about wind and migration. RESULTS Contrary to our predictions, compensation did not increase linearly with distance traveled, was not constrained during flight over open ocean, and did not influence where an individual ultimately crossed over the northern coast of the Gulf of Mexico at the end of this flight. Instead, we found a strong preference for full compensation throughout godwit flight paths. CONCLUSIONS Our results indicate that compensation is crucial to godwits, emphasizing the role of risk in shaping migratory behavior and raising questions about the consequences of changing wind regimes for other barrier-crossing aerial migrants.
Collapse
Affiliation(s)
- Jennifer A Linscott
- Department of Biological Sciences, University of South Carolina, 715 Sumter Street, Columbia, SC, 29208, USA.
| | - Juan G Navedo
- Estacion Experimental Quempillén, Facultad de Ciencias, Universidad Austral de Chile, Ancud, Chiloé, Chile
- Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile
| | - Sarah J Clements
- School of Natural Resources, University of Missouri, 103 Anheuser-Busch Natural Resources Building, Columbia, MO, 65211, USA
| | - Jason P Loghry
- Texas A&M University, Kingsville, 700 University Blvd., MSC 218, Kingsville, TX, 78363, USA
| | - Jorge Ruiz
- Estacion Experimental Quempillén, Facultad de Ciencias, Universidad Austral de Chile, Ancud, Chiloé, Chile
- Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile
| | - Bart M Ballard
- Texas A&M University, Kingsville, 700 University Blvd., MSC 218, Kingsville, TX, 78363, USA
| | - Mitch D Weegman
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK, S7N 5E2, Canada
| | - Nathan R Senner
- Department of Biological Sciences, University of South Carolina, 715 Sumter Street, Columbia, SC, 29208, USA
| |
Collapse
|
12
|
Performance of polarization-sensitive neurons of the locust central complex at different degrees of polarization. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2022; 208:387-403. [PMID: 35157117 PMCID: PMC9123078 DOI: 10.1007/s00359-022-01545-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 01/18/2022] [Accepted: 01/25/2022] [Indexed: 10/29/2022]
Abstract
The polarization pattern of the sky is exploited by many insects for spatial orientation and navigation. It derives from Rayleigh scattering in the atmosphere and depends directly on the position of the sun. In the insect brain, the central complex (CX) houses neurons tuned to the angle of polarization (AoP), that together constitute an internal compass for celestial navigation. Polarized light is not only characterized by the AoP, but also by the degree of polarization (DoP), which can be highly variable, depending on sky conditions. Under a clear sky, the DoP of polarized sky light may reach up to 0.75 but is usually much lower especially when light is scattered by clouds or haze. To investigate how the polarization-processing network of the CX copes with low DoPs, we recorded intracellularly from neurons of the locust CX at different stages of processing, while stimulating with light of different DoPs. Significant responses to polarized light occurred down to DoPs of 0.05 indicating reliable coding of the AoP even at unfavorable sky conditions. Moreover, we found that the activity of neurons at the CX input stage may be strongly influenced by nearly unpolarized light, while the activity of downstream neurons appears less affected.
Collapse
|
13
|
Takahashi N, Zittrell F, Hensgen R, Homberg U. Receptive field structures for two celestial compass cues at the input stage of the central complex in the locust brain. J Exp Biol 2022; 225:274503. [DOI: 10.1242/jeb.243858] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/14/2022] [Indexed: 11/20/2022]
Abstract
Successful navigation depends on an animal's ability to perceive its spatial orientation relative to visual surroundings. Heading direction in insects is represented in the central complex (CX), a navigation center in the brain, to generate steering commands. In insects that navigate relative to sky compass signals, CX neurons are tuned to celestial cues indicating the location of the sun. The desert locust CX contains a compass-like representation of two related celestial cues: the direction of unpolarized direct sunlight and the pattern of polarized light, which depends on the sun position. Whether congruent tuning to these two compass cues emerges within the CX network or is inherited from CX input neurons is unclear. To address this question, we intracellularly recorded from GABA-immunoreactive TL neurons, input elements to the locust CX (corresponding to R neurons in Drosophila), while applying visual stimuli simulating unpolarized sunlight and polarized light across the hemisphere above the animal. We show that TL neurons have large receptive fields for both types of stimuli. However, faithful integration of polarization angles across the dorsal hemisphere, or matched-filter ability to encode particular sun positions, was found in only two out of 22 recordings. Those two neurons also showed a good match in sun position coding through polarized and unpolarized light signaling, whereas 20 neurons showed substantial mismatch in signaling of the two compass cues. The data, therefore, suggest that considerable refinement of azimuth coding based on sky compass signals occurs at the synapses from TL neurons to postsynaptic CX compass neurons.
Collapse
Affiliation(s)
- Naomi Takahashi
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, D-35032 Marburg, Germany
| | - Frederick Zittrell
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, D-35032 Marburg, Germany
| | - Ronja Hensgen
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, D-35032 Marburg, Germany
| | - Uwe Homberg
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, D-35032 Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Germany
| |
Collapse
|
14
|
Packmor F, Kishkinev D, Bittermann F, Kofler B, Machowetz C, Zechmeister T, Zawadzki LC, Guilford T, Holland RA. A magnet attached to the forehead disrupts magnetic compass orientation in a migratory songbird. J Exp Biol 2021; 224:jeb243337. [PMID: 34713887 PMCID: PMC8645232 DOI: 10.1242/jeb.243337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 10/25/2021] [Indexed: 11/20/2022]
Abstract
For studies on magnetic compass orientation and navigation performance in small bird species, controlled experiments with orientation cages inside an electromagnetic coil system are the most prominent methodological paradigm. These are, however, not applicable when studying larger bird species and/or orientation behaviour during free flight. For this, researchers have followed a very different approach, attaching small magnets to birds, with the intention of depriving them of access to meaningful magnetic information. Unfortunately, results from studies using this approach appear rather inconsistent. As these are based on experiments with birds under free-flight conditions, which usually do not allow exclusion of other potential orientation cues, an assessment of the overall efficacy of this approach is difficult to conduct. Here, we directly tested the efficacy of small magnets for temporarily disrupting magnetic compass orientation in small migratory songbirds using orientation cages under controlled experimental conditions. We found that birds which have access to the Earth's magnetic field as their sole orientation cue show a general orientation towards their seasonally appropriate migratory direction. When carrying magnets on their forehead under these conditions, the same birds become disoriented. However, under changed conditions that allow birds access to other (i.e. celestial) orientation cues, any disruptive effect of the magnets they carry appears obscured. Our results provide clear evidence for the efficacy of the magnet approach for temporarily disrupting magnetic compass orientation in birds, but also reveal its limitations for application in experiments under free-flight conditions.
Collapse
Affiliation(s)
- Florian Packmor
- School of Natural Sciences, Bangor University, Bangor LL57 2UW, UK
- Institute of Avian Research ‘Vogelwarte Helgoland’, Wilhelmshaven 26386, Germany
| | - Dmitry Kishkinev
- School of Life Sciences, Keele University, Newcastle-under-Lyme ST5 5BG, UK
| | - Flora Bittermann
- Biological Station Lake Neusiedl, Illmitz 7142, Austria
- Nationalpark Neusiedler See – Seewinkel, Apetlon 7143, Austria
- Austrian Ornithological Centre, Konrad-Lorenz Institute of Ethology, University of Veterinary Medicine Vienna, 1160 Wien, Austria
| | | | - Clara Machowetz
- Biological Station Lake Neusiedl, Illmitz 7142, Austria
- Nationalpark Neusiedler See – Seewinkel, Apetlon 7143, Austria
- Austrian Ornithological Centre, Konrad-Lorenz Institute of Ethology, University of Veterinary Medicine Vienna, 1160 Wien, Austria
| | | | | | - Tim Guilford
- Department of Zoology, Oxford University, Oxford OX1 3SZ, UK
| | | |
Collapse
|
15
|
Chappell DR, Horan TM, Speiser DI. Panoramic spatial vision in the bay scallop Argopecten irradians. Proc Biol Sci 2021; 288:20211730. [PMID: 34753355 PMCID: PMC8580434 DOI: 10.1098/rspb.2021.1730] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 10/20/2021] [Indexed: 11/12/2022] Open
Abstract
We have a growing understanding of the light-sensing organs and light-influenced behaviours of animals with distributed visual systems, but we have yet to learn how these animals convert visual input into behavioural output. It has been suggested they consolidate visual information early in their sensory-motor pathways, resulting in them being able to detect visual cues (spatial resolution) without being able to locate them (spatial vision). To explore how an animal with dozens of eyes processes visual information, we analysed the responses of the bay scallop Argopecten irradians to both static and rotating visual stimuli. We found A. irradians distinguish between static visual stimuli in different locations by directing their sensory tentacles towards them and were more likely to point their extended tentacles towards larger visual stimuli. We also found that scallops track rotating stimuli with individual tentacles and with rotating waves of tentacle extension. Our results show, to our knowledge for the first time that scallops have both spatial resolution and spatial vision, indicating their sensory-motor circuits include neural representations of their visual surroundings. Exploring a wide range of animals with distributed visual systems will help us learn the different ways non-cephalized animals convert sensory input into behavioural output.
Collapse
Affiliation(s)
- Daniel R. Chappell
- Department of Biological Sciences, University of South Carolina, 715 Sumter Street, Columbia, SC 29208, USA
| | - Tyler M. Horan
- Department of Biological Sciences, University of South Carolina, 715 Sumter Street, Columbia, SC 29208, USA
| | - Daniel I. Speiser
- Department of Biological Sciences, University of South Carolina, 715 Sumter Street, Columbia, SC 29208, USA
| |
Collapse
|
16
|
Aguayo-Adán JA, Rouco C, Delibes-Mateos M, Santoro S. Lack of evidence for differences in the spread of classic (Lagovirus europaeus/GI.1) and novel (Lagovirus europaeus/GI.2) rabbit haemorrhagic disease viruses in Europe and North Africa. Vet Rec 2021; 190:e1067. [PMID: 34713453 DOI: 10.1002/vetr.1067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 08/15/2021] [Accepted: 10/03/2021] [Indexed: 01/18/2023]
Abstract
BACKGROUND Fast-spreading diseases affecting wildlife populations threaten biodiversity. Two caliciviruses, Lagovirus europaeus/GI.1 and Lagovirus europaeus/GI.2, caused rabbit haemorrhagic disease virus (RHDV) in wild rabbits. Despite having different characteristics, these variants spread quickly, posing a threat to wild rabbit populations. METHODS In this study, we conducted a thorough review of the scientific literature and reports of international organisations of first detections of both variants of RHDV in the Euro-Mediterranean region. We concentrated on this area to avoid bias due to intentional human introductions. RESULTS The estimated mean spread rate of GI.2 was higher than that of GI.1 (GI.2: 479 km/year, range: 47-7346; GI.1: 330 km/year, 37-6248). These differences were not statistically significant. This lack of difference may be due to the interactions between each variant's virulence characteristics. Humans may have a dominant effect on their spread. Potential limitations associated with the observational process could have hindered our ability to identify statistical differences. CONCLUSIONS The lack of difference in the spread patterns of the two variants could be due to a biological cause, human facilitation or a lack of statistical power. Adapting protocols to detect diseases in wildlife using homogeneous criteria will be indispensable in the coming years.
Collapse
Affiliation(s)
- Juan Antonio Aguayo-Adán
- Departamento de Botánica, Ecología y Fisiología Vegetal, Área de Ecología, Universidad de Córdoba, Córdoba, Spain
| | - Carlos Rouco
- Departamento de Botánica, Ecología y Fisiología Vegetal, Área de Ecología, Universidad de Córdoba, Córdoba, Spain.,Sociedad, Ecología y Gestión del Medio Ambiente, UCO-IESA, Unidad Asociada al CSIC, Universidad de Córdoba, Córdoba, Spain
| | - Miguel Delibes-Mateos
- Sociedad, Ecología y Gestión del Medio Ambiente, UCO-IESA, Unidad Asociada al CSIC, Universidad de Córdoba, Córdoba, Spain.,IESA-CSIC, Instituto de Estudios Sociales Avanzados, Córdoba, Spain
| | - Simone Santoro
- Departamento de Ciencias Integradas, Facultad de Ciencias Experimentales, Universidad de Huelva, Huelva, Spain
| |
Collapse
|
17
|
Augugliaro C, Anile S, Munkhtsog B, Janchivlamdan C, Batzorig E, Mazzon I, Nielsen C. Activity overlap between mesocarnivores and prey in the Central Mongolian steppe. ETHOL ECOL EVOL 2021. [DOI: 10.1080/03949370.2021.1975312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Claudio Augugliaro
- Department of Research and Conservation, Wildlife Initiative NGO, Ulaanbaatar 210349, Mongolia
| | - Stefano Anile
- Cooperative Wildlife Research Laboratory, Southern Illinois University, Carbondale, IL 62901, USA
| | - Bariushaa Munkhtsog
- Institute of Biology, Mongolian Academy of Sciences, Ulaanbaatar 13330, Mongolia
| | - Choikhand Janchivlamdan
- Department of Research and Conservation, Wildlife Initiative NGO, Ulaanbaatar 210349, Mongolia
| | - Enkhzorig Batzorig
- Department of Biology, National University of Mongolia, Ulaanbaatar 14201, Mongolia
| | - Ivan Mazzon
- Department of Research and Conservation, Wildlife Initiative NGO, Ulaanbaatar 210349, Mongolia
| | - Clayton Nielsen
- Cooperative Wildlife Research Laboratory, Southern Illinois University, Carbondale, IL 62901, USA
| |
Collapse
|
18
|
Di Marzio M, Fensore S, Lafratta G, Taylor CC. The package: nonparametric regression using local rotation matrices in. J STAT COMPUT SIM 2021. [DOI: 10.1080/00949655.2021.1890735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
19
|
Zalewska K, Waggershauser CN, Kortland K, Lambin X. The best defence is not being there: avoidance of larger carnivores is not driven by risk intensity. J Zool (1987) 2021. [DOI: 10.1111/jzo.12910] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- K. Zalewska
- School of Biological Sciences University of Aberdeen Aberdeen UK
| | | | - K. Kortland
- Forestry and Land Scotland Smithton, Inverness UK
- Cairngorms Connect Achantoul, Aviemore UK
| | - X. Lambin
- School of Biological Sciences University of Aberdeen Aberdeen UK
| |
Collapse
|
20
|
Sumner-Rooney L, Kirwan JD, Lüter C, Ullrich-Lüter E. Run and hide: visual performance in a brittle star. J Exp Biol 2021; 224:jeb236653. [PMID: 34100540 PMCID: PMC8214828 DOI: 10.1242/jeb.236653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 04/12/2021] [Indexed: 11/24/2022]
Abstract
Spatial vision was recently reported in a brittle star, Ophiomastix wendtii, which lacks discrete eyes, but little is known about its visual ecology. Our aim was to better characterize the vision and visual ecology of this unusual visual system. We tested animal orientation relative to vertical bar stimuli at a range of angular widths and contrasts, to identify limits of angular and contrast detection. We also presented dynamic shadow stimuli, either looming towards or passing the animal overhead, to test for potential defensive responses. Finally, we presented animals lacking a single arm with a vertical bar stimulus known to elicit a response in intact animals. We found that O. wendtii orients to large (≥50 deg), high-contrast vertical bar stimuli, consistent with a shelter-seeking role and with photoreceptor acceptance angles estimated from morphology. We calculate poor optical sensitivity for individual photoreceptors, and predict dramatic oversampling for photoreceptor arrays. We also report responses to dark stimuli moving against a bright background - this is the first report of responses to moving stimuli in brittle stars and suggests additional defensive uses for vision in echinoderms. Finally, we found that animals missing a single arm orient less well to static stimuli, which requires further investigation.
Collapse
Affiliation(s)
- Lauren Sumner-Rooney
- Oxford University Museum of Natural History, University of Oxford, Parks Road, Oxford OX1 3PW, UK
| | - John D. Kirwan
- Stazione Zoologica Anton Dohrn, Via Francesco Caracciolo, 333, 80122 Naples, Italy
| | - Carsten Lüter
- Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity, Invalidenstrasse 43, 10115 Berlin, Germany
| | - Esther Ullrich-Lüter
- Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity, Invalidenstrasse 43, 10115 Berlin, Germany
| |
Collapse
|
21
|
Davis RS, Yarnell RW, Gentle LK, Uzal A, Mgoola WO, Stone EL. Prey availability and intraguild competition regulate the spatiotemporal dynamics of a modified large carnivore guild. Ecol Evol 2021; 11:7890-7904. [PMID: 34188859 PMCID: PMC8216965 DOI: 10.1002/ece3.7620] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 04/08/2021] [Accepted: 04/13/2021] [Indexed: 11/10/2022] Open
Abstract
Effective conservation management requires an understanding of the spatiotemporal dynamics driving large carnivore density and resource partitioning. In African ecosystems, reduced prey populations and the loss of competing guild members, most notably lion (Panthera leo), are expected to increase the levels of competition between remaining carnivores. Consequently, intraguild relationships can be altered, potentially increasing the risk of further population decline. Kasungu National Park (KNP), Malawi, is an example of a conservation area that has experienced large-scale reductions in both carnivore and prey populations, leaving a resident large carnivore guild consisting of only leopard (Panthera pardus) and spotted hyena (Crocuta crocuta). Here, we quantify the spatiotemporal dynamics of these two species and their degree of association, using a combination of co-detection modeling, time-to-event analyses, and temporal activity patterns from camera trap data. The detection of leopard and spotted hyena was significantly associated with the detection of preferred prey and competing carnivores, increasing the likelihood of species interaction. Temporal analyses revealed sex-specific differences in temporal activity, with female leopard activity patterns significantly different to those of spotted hyena and male conspecifics. Heightened risk of interaction with interspecific competitors and male conspecifics may have resulted in female leopards adopting temporal avoidance strategies to facilitate coexistence. Female leopard behavioral adaptations increased overall activity levels and diurnal activity rates, with potential consequences for overall fitness and exposure to sources of mortality. As both species are currently found at low densities in KNP, increased risk of competitive interactions, which infer a reduction in fitness, could have significant implications for large carnivore demographics. The protection of remaining prey populations is necessary to mitigate interspecific competition and avoid further alterations to the large carnivore guild.
Collapse
Affiliation(s)
- Robert S. Davis
- School of Animal, Rural and Environmental SciencesNottingham Trent UniversityBrackenhurst CampusSouthwellUK
- Conservation Research Africa & Carnivore Research MalawiLilongweMalawi
| | - Richard W. Yarnell
- School of Animal, Rural and Environmental SciencesNottingham Trent UniversityBrackenhurst CampusSouthwellUK
| | - Louise K. Gentle
- School of Animal, Rural and Environmental SciencesNottingham Trent UniversityBrackenhurst CampusSouthwellUK
| | - Antonio Uzal
- School of Animal, Rural and Environmental SciencesNottingham Trent UniversityBrackenhurst CampusSouthwellUK
| | | | - Emma L. Stone
- Conservation Research Africa & Carnivore Research MalawiLilongweMalawi
- Department of Applied SciencesUniversity of the West of EnglandBristolUK
| |
Collapse
|
22
|
Phenological responses to climate change based on a hundred years of herbarium collections of tropical Melastomataceae. PLoS One 2021; 16:e0251360. [PMID: 33961684 PMCID: PMC8104365 DOI: 10.1371/journal.pone.0251360] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 04/23/2021] [Indexed: 11/19/2022] Open
Abstract
Changes in phenological events have been vastly documented in face of recent global climate change. These studies are concentrated on temperate plants, and the responses of tropical species are still little understood, likely due to the lack of long-term phenological records in the tropics. In this case, the use of herbarium specimens to gather phenological data over long periods and wide geographic areas has emerged as a powerful tool. Here, we used four Melastomataceae species endemic to the Brazilian Atlantic Forest to evaluate phenological patterns and alterations as responses to recent climate changes. Phenological data were gathered from Reflora Virtual Herbarium specimens collected between 1920 and 2018, and analyzed with circular statistics applied to the intervals 1920–1979, 1980–1999, and 2000–2018. The effects of temperature range, average temperature, precipitation, and photoperiod on flowering and fruiting of each species were tested using multiple linear regressions. Through circular statistics, we detected changes, mostly delays, in the flowering of Miconia quinquedentata, Pleroma clavatum and P. trichopodum, and in the fruiting of M. acutiflora, P. clavatum and P. trichopodum. We also found that flowering and fruiting occurrence were related to local climatic conditions from months prior to the collections. We found marked phenological variations over the decades and also that these variations are associated to global climate change, adding up to the large body of evidence from higher latitudes. Our results also support herbarium collections as an important source for long-term tropical phenological studies. The lack of consistent patterns of responses among the four species (e.g. fruiting delayed two months in P. clavatum and advanced one month in M. acutiflora) suggests that climate change has unequal effects across tropical forests. This highlights the urgent need for further research to understand and forecast the ecological implications of these changes in global ecosystems processes.
Collapse
|
23
|
Lindecke O, Holland RA, Pētersons G, Voigt CC. Corneal sensitivity is required for orientation in free-flying migratory bats. Commun Biol 2021; 4:522. [PMID: 33953327 PMCID: PMC8100159 DOI: 10.1038/s42003-021-02053-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 03/26/2021] [Indexed: 02/03/2023] Open
Abstract
The exact anatomical location for an iron particle-based magnetic sense remains enigmatic in vertebrates. For mammals, findings from a cornea anaesthesia experiment in mole rats suggest that it carries the primary sensors for magnetoreception. Yet, this has never been tested in a free-ranging mammal. Here, we investigated whether intact corneal sensation is crucial for navigation in migrating Nathusius' bats, Pipistrellus nathusii, translocated from their migratory corridor. We found that bats treated with corneal anaesthesia in both eyes flew in random directions after translocation and release, contrasting bats with a single eye treated, and the control group, which both oriented in the seasonally appropriate direction. Using a Y-maze test, we confirmed that light detection remained unaffected by topical anaesthesia. Therefore our results suggest the cornea as a possible site of magnetoreception in bats, although other conceivable effects of the anaesthetic are also explored. Furthermore, we demonstrate that the corneal based sense is of bilateral nature but can function in a single eye if necessary.
Collapse
Affiliation(s)
- Oliver Lindecke
- grid.418779.40000 0001 0708 0355Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany ,grid.14095.390000 0000 9116 4836AG Verhaltensbiologie, Institute of Biology, Freie Universität Berlin, Berlin, Germany
| | - Richard A. Holland
- grid.7362.00000000118820937School of Natural Sciences, Bangor University, Bangor, Gwynedd UK
| | - Gunārs Pētersons
- grid.22657.340000 0001 2169 9162Faculty of Veterinary Medicine, Latvia University of Life Sciences and Technologies, Jelgava, Latvia
| | - Christian C. Voigt
- grid.418779.40000 0001 0708 0355Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany ,grid.14095.390000 0000 9116 4836AG Verhaltensbiologie, Institute of Biology, Freie Universität Berlin, Berlin, Germany
| |
Collapse
|
24
|
|
25
|
Helfrich-Förster C, Monecke S, Spiousas I, Hovestadt T, Mitesser O, Wehr TA. Women temporarily synchronize their menstrual cycles with the luminance and gravimetric cycles of the Moon. SCIENCE ADVANCES 2021; 7:eabe1358. [PMID: 33571128 PMCID: PMC7840133 DOI: 10.1126/sciadv.abe1358] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Accepted: 12/21/2020] [Indexed: 05/03/2023]
Abstract
Many species synchronize reproductive behavior with a particular phase of the lunar cycle to increase reproductive success. In humans, a lunar influence on reproductive behavior remains controversial, although the human menstrual cycle has a period close to that of the lunar cycle. Here, we analyzed long-term menstrual recordings of individual women with distinct methods for biological rhythm analysis. We show that women's menstrual cycles with a period longer than 27 days were intermittently synchronous with the Moon's luminance and/or gravimetric cycles. With age and upon exposure to artificial nocturnal light, menstrual cycles shortened and lost this synchrony. We hypothesize that in ancient times, human reproductive behavior was synchronous with the Moon but that our modern lifestyles have changed reproductive physiology and behavior.
Collapse
Affiliation(s)
- C Helfrich-Förster
- Neurobiology and Genetics, Biocenter, Julius-Maximilians University of Würzburg, Germany.
| | - S Monecke
- Institute of Medical Psychology, Ludwig-Maximilians University of Munich, Germany
| | - I Spiousas
- Universidad Nacional de Quilmes, Buenos Aires, Argentina
| | - T Hovestadt
- Theoretical Evolutionary Ecology Group, Biocenter, Department of Animal Ecology and Tropical Biology, Julius-Maximilians University of Würzburg, Germany
| | - O Mitesser
- Field Station Fabrikschleichach, Biocenter, Julius-Maximilians University of Würzburg, Germany
| | - T A Wehr
- Intramural Research Program, National Institute of Mental Health, Bethesda, MD, USA
| |
Collapse
|
26
|
Pietra S, Ng K, Lawrence PA, Casal J. Planar cell polarity in the larval epidermis of Drosophila and the role of microtubules. Open Biol 2020; 10:200290. [PMID: 33295841 PMCID: PMC7776564 DOI: 10.1098/rsob.200290] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
We investigate planar cell polarity (PCP) in the Drosophila larval epidermis. The intricate pattern of denticles depends on only one system of PCP, the Dachsous/Fat system. Dachsous molecules in one cell bind to Fat molecules in a neighbour cell to make intercellular bridges. The disposition and orientation of these Dachsous–Fat bridges allows each cell to compare two neighbours and point its denticles towards the neighbour with the most Dachsous. Measurements of the amount of Dachsous reveal a peak at the back of the anterior compartment of each segment. Localization of Dachs and orientation of ectopic denticles help reveal the polarity of every cell. We discuss whether these findings support our gradient model of Dachsous activity. Several groups have proposed that Dachsous and Fat fix the direction of PCP via oriented microtubules that transport PCP proteins to one side of the cell. We test this proposition in the larval cells and find that most microtubules grow perpendicularly to the axis of PCP. We find no meaningful bias in the polarity of microtubules aligned close to that axis. We also reexamine published data from the pupal abdomen and find no evidence supporting the hypothesis that microtubular orientation draws the arrow of PCP.
Collapse
Affiliation(s)
- Stefano Pietra
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - KangBo Ng
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Peter A Lawrence
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - José Casal
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| |
Collapse
|
27
|
Caspar KR, Moldenhauer K, Moritz RE, Němec P, Malkemper EP, Begall S. Eyes are essential for magnetoreception in a mammal. J R Soc Interface 2020; 17:20200513. [PMID: 32993431 PMCID: PMC7536053 DOI: 10.1098/rsif.2020.0513] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 09/02/2020] [Indexed: 11/12/2022] Open
Abstract
Several groups of mammals use the Earth's magnetic field for orientation, but their magnetosensory organ remains unknown. The Ansell's mole-rat (Fukomys anselli, Bathyergidae, Rodentia) is a microphthalmic subterranean rodent with innate magnetic orientation behaviour. Previous studies on this species proposed that its magnetoreceptors are located in the eye. To test this hypothesis, we assessed magnetic orientation in mole-rats after the surgical removal of their eyes compared to untreated controls. Initially, we demonstrate that this enucleation does not lead to changes in routine behaviours, including locomotion, feeding and socializing. We then studied magnetic compass orientation by employing a well-established nest-building assay under four magnetic field alignments. In line with previous studies, control animals exhibited a significant preference to build nests in magnetic southeast. By contrast, enucleated mole-rats built nests in random magnetic orientations, suggesting an impairment of their magnetic sense. The results provide robust support for the hypothesis that mole-rats perceive magnetic fields with their minute eyes, probably relying on magnetite-based receptors in the cornea.
Collapse
Affiliation(s)
- Kai R. Caspar
- Department of General Zoology, University of Duisburg-Essen, Universitaetsstr. 5, 45117 Essen, Germany
| | - Katrin Moldenhauer
- Department of General Zoology, University of Duisburg-Essen, Universitaetsstr. 5, 45117 Essen, Germany
| | - Regina E. Moritz
- Department of General Zoology, University of Duisburg-Essen, Universitaetsstr. 5, 45117 Essen, Germany
- Department Vision, Visual Impairment & Blindness, Faculty 13, Technical University of Dortmund, Emil-Figge-Straße 50, 44227 Dortmund, Germany
| | - Pavel Němec
- Department of Zoology, Faculty of Science, Charles University, Vinicna 7, 12844 Prague, Czech Republic
| | - E. Pascal Malkemper
- Max Planck Research Group Neurobiology of Magnetoreception, Center of Advanced European Studies and Research (CAESAR), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Sabine Begall
- Department of General Zoology, University of Duisburg-Essen, Universitaetsstr. 5, 45117 Essen, Germany
- Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, 16521 Prague 6, Czech Republic
| |
Collapse
|
28
|
Landler L, Ruxton GD, Malkemper EP. Grouped circular data in biology: advice for effectively implementing statistical procedures. Behav Ecol Sociobiol 2020; 74:100. [PMID: 32728310 PMCID: PMC7373216 DOI: 10.1007/s00265-020-02881-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 07/07/2020] [Accepted: 07/13/2020] [Indexed: 11/16/2022]
Abstract
Abstract The most common statistical procedure with a sample of circular data is to test the null hypothesis that points are spread uniformly around the circle without a preferred direction. An array of tests for this has been developed. However, these tests were designed for continuously distributed data, whereas often (e.g. due to limited precision of measurement techniques) collected data is aggregated into a set of discrete values (e.g. rounded to the nearest degree). This disparity can cause an uncontrolled increase in type I error rate, an effect that is particularly problematic for tests that are based on the distribution of arc lengths between adjacent points (such as the Rao spacing test). Here, we demonstrate that an easy-to-apply modification can correct this problem, and we recommend this modification when using any test, other than the Rayleigh test, of circular uniformity on aggregated data. We provide R functions for this modification for several commonly used tests. In addition, we tested the power of a recently proposed test, the Gini test. However, we concluded that it lacks sufficient increase in power to replace any of the tests already in common use. In conclusion, using any of the standard circular tests (except the Rayleigh test) without modifications on rounded/aggregated data, especially with larger sample sizes, will increase the proportion of false-positive results—but we demonstrate that a simple and general modification avoids this problem. Significance statement Circular data are widespread across biological disciplines, e.g. in orientation studies or circadian rhythms. Often these data are rounded to the nearest 1–10 degrees. We have shown previously that this leads to an inflation of false-positive results when testing whether the data is significantly different from a random distribution using the Rao test. Here we present a modification that avoids this increase in false-positives for rounded data while retaining statistical power for a variety of tests. In sum, we provide comprehensive guidance on how best to test for departure from uniformity in non-continuous data. Electronic supplementary material The online version of this article (10.1007/s00265-020-02881-6) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Lukas Landler
- Institute of Zoology, University of Natural Resources and Life Sciences, Gregor-Mendel-Straße 33/I, 1180 Vienna, Austria
| | - Graeme D Ruxton
- School of Biology, University of St Andrews, St Andrews, KY16 9TH UK
| | - E Pascal Malkemper
- Max Planck Research Group Neurobiology of Magnetoreception, Center of Advanced European Studies and Research (CAESAR), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| |
Collapse
|
29
|
Landler L, Ruxton GD, Malkemper EP. Model selection versus traditional hypothesis testing in circular statistics: a simulation study. Biol Open 2020; 9:bio049866. [PMID: 32554482 PMCID: PMC7327993 DOI: 10.1242/bio.049866] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 05/27/2020] [Indexed: 11/20/2022] Open
Abstract
Many studies in biology involve data measured on a circular scale. Such data require different statistical treatment from those measured on linear scales. The most common statistical exploration of circular data involves testing the null hypothesis that the data show no aggregation and are instead uniformly distributed over the whole circle. The most common means of performing this type of investigation is with a Rayleigh test. An alternative might be to compare the fit of the uniform distribution model to alternative models. Such model-fitting approaches have become a standard technique with linear data, and their greater application to circular data has been recently advocated. Here we present simulation data that demonstrate that such model-based inference can offer very similar performance to the best traditional tests, but only if adjustment is made in order to control type I error rate.
Collapse
Affiliation(s)
- Lukas Landler
- Institute of Zoology, Department of Integrative Biology and Biodiversity Research, University of Natural Resources and Life Sciences Vienna, Gregor-Mendel-Strasse 33, A-1180 Vienna, Austria
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Graeme D Ruxton
- School of Biology, University of St Andrews, St Andrews KY16 9TH, UK
| | - E Pascal Malkemper
- Max Planck Research Group Neurobiology of Magnetoreception, Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, Bonn 53175, Germany
| |
Collapse
|
30
|
Magnetic compass orientation in common midwife toad tadpoles, Alytes obstetricans (Anura, Alytidae). J ETHOL 2020. [DOI: 10.1007/s10164-020-00653-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
31
|
Fitak RR, Wheeler BR, Johnsen S. Effect of a magnetic pulse on orientation behavior in rainbow trout (Oncorhynchus mykiss). Behav Processes 2020; 172:104058. [PMID: 31954808 DOI: 10.1016/j.beproc.2020.104058] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 01/01/2020] [Accepted: 01/15/2020] [Indexed: 11/30/2022]
Abstract
Magnetoreception remains one of the most enigmatic of animal senses. Rainbow trout (Oncorhynchus mykiss) represent an ideal species to study this sense, as magnetoreception based upon microscopic particles of magnetite is suspected to play an important role in their orientation and navigation. Here we found that compared with controls, a magnetic pulse (a treatment commonly used to demonstrate magnetite-based magnetoreception) can induce orientation behavior in juvenile rainbow trout on a specific experimental day. Multiple circular-linear regression also indicated that this effect could at least be partially explained by daily variation in solar electromagnetic activity (i.e., sunspot count and disturbance storm time index). These results are consistent with magnetite-based magnetoreception in rainbow trout and suggest that 1) solar activity may impact magnetic orientation and 2) researchers should be cognizant of its potential consequences on studies of magnetoreception.
Collapse
Affiliation(s)
- Robert R Fitak
- Department of Biology, Duke University, Durham, NC 27708 USA.
| | | | - Sönke Johnsen
- Department of Biology, Duke University, Durham, NC 27708 USA
| |
Collapse
|
32
|
Extraocular Vision in a Brittle Star Is Mediated by Chromatophore Movement in Response to Ambient Light. Curr Biol 2020; 30:319-327.e4. [PMID: 31902727 DOI: 10.1016/j.cub.2019.11.042] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 09/27/2019] [Accepted: 11/13/2019] [Indexed: 01/01/2023]
Abstract
Almost all animals can sense light, but only those with spatial vision can "see." Conventionally, this was restricted to animals possessing discrete visual organs (eyes), but extraocular vision could facilitate vision without eyes. Echinoderms form the focus of extraocular vision research [1-7], and the brittle star Ophiocoma wendtii, which exhibits light-responsive color change and shelter seeking, became a key species of interest [4, 8, 9]. Both O. wendtii and an apparently light-indifferent congeneric, O. pumila, possess an extensive network of r-opsin-reactive cells, but its function remains unclear [4]. We show that, although both species are strongly light averse, O. wendtii orients to stimuli necessitating spatial vision for detection, but O. pumila does not. However, O. wendtii's response disappears when chromatophores are contracted within the skeleton. Combining immunohistochemistry, histology, and synchrotron microtomography, we reconstructed models of photoreceptors in situ and extracted estimated angular apertures for O. wendtii and O. pumila. Angular sensitivity estimates, derived from these models, support the hypothesis that chromatophores constitute a screening mechanism in O. wendtii, providing sufficient resolving power to detect the stimuli. RNA sequencing (RNA-seq) identified opsin candidates in both species, including multiple r-opsins and transduction pathway constituents, congruent with immunohistochemistry and studies of other echinoderms [10, 11]. Finally, we note that differing body postures between the two species during experiments may reflect aspect of signal integration. This represents one of the most detailed mechanisms for extraocular vision yet proposed and draws interesting parallels with the only other confirmed extraocular visual system, that of some sea urchins, which also possess chromatophores [1].
Collapse
|
33
|
Landler L, Ruxton GD, Malkemper EP. The Hermans-Rasson test as a powerful alternative to the Rayleigh test for circular statistics in biology. BMC Ecol 2019; 19:30. [PMID: 31391040 PMCID: PMC6686250 DOI: 10.1186/s12898-019-0246-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 07/27/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Circular data are gathered in diverse fields of science where measured traits are cyclical in nature: such as compass directions or times of day. The most common statistical question asked of a sample of circular data is whether the data seems to be drawn from a uniform distribution or one that is concentrated around one or more preferred directions. The overwhelmingly most-popular test of the null hypothesis of uniformity is the Rayleigh test, even though this test is known to have very low power in some circumstances. Here we present simulation studies evaluating the performance of tests developed as alternatives to the Rayleigh test. RESULTS The results of our simulations demonstrate that a single test, the Hermans and Rasson test is almost as powerful as the Rayleigh test in unimodal situations (when the Rayleigh test does well) but substantially outperforms the Rayleigh test in multimodal situations. CONCLUSION We recommend researchers switch to routine use of the new Hermans and Rasson test. We also demonstrate that all available tests have low power to detect departures from uniformity involving more than two concentrated regions: we recommend that where researchers suspect such complex departures that they collect substantially-sized samples and apply another recent test due to Pycke that was designed specifically for such complex cases. We provide clear textual descriptions of how to implement each of these recommended tests and encode them in R functions that we provide.
Collapse
Affiliation(s)
- Lukas Landler
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria
| | - Graeme D Ruxton
- School of Biology, University of St Andrews, St Andrews, KY16 9TH, UK
| | - E Pascal Malkemper
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria.
| |
Collapse
|
34
|
Kingston ACN, Chappell DR, Speiser DI. Evidence for spatial vision in Chiton tuberculatus, a chiton with eyespots. ACTA ACUST UNITED AC 2018; 221:jeb.183632. [PMID: 30127078 DOI: 10.1242/jeb.183632] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 08/07/2018] [Indexed: 11/20/2022]
Abstract
To better understand relationships between the structures and functions of the distributed visual systems of chitons, we compare how morphological differences between the light-sensing structures of these animals relate to their visually guided behaviors. All chitons have sensory organs - termed aesthetes - embedded within their protective shell plates. In some species, the aesthetes are interspersed with small, image-forming eyes. In other species, the aesthetes are paired with pigmented eyespots. Previously, we compared the visually influenced behaviors of chitons with aesthetes to those of chitons with both aesthetes and eyes. Here, we characterize the visually influenced behaviors of chitons with aesthetes and eyespots. We find that chitons with eyespots engage in behaviors consistent with spatial vision, but appear to use spatial vision for different tasks than chitons with eyes. Unlike chitons with eyes, Chiton tuberculatus and C. marmoratus fail to distinguish between sudden appearances of overhead objects and equivalent, uniform changes in light levels. We also find that C. tuberculatus orients to static objects with angular sizes as small as 10 deg. Thus, C. tuberculatus demonstrates spatial resolution that is at least as fine as that demonstrated by chitons with eyes. The eyespots of Chiton are smaller and more numerous than the eyes found in other chitons and they are separated by angles of <0.5 deg, suggesting that the light-influenced behaviors of Chiton may be more accurately predicted by the network properties of their distributed visual system than by the structural properties of their individual light-detecting organs.
Collapse
Affiliation(s)
- Alexandra C N Kingston
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Daniel R Chappell
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Daniel I Speiser
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| |
Collapse
|
35
|
Circular data in biology: advice for effectively implementing statistical procedures. Behav Ecol Sociobiol 2018; 72:128. [PMID: 30100666 PMCID: PMC6060829 DOI: 10.1007/s00265-018-2538-y] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 06/19/2018] [Accepted: 06/22/2018] [Indexed: 12/21/2022]
Abstract
Circular data are common in biological studies. The most fundamental question that can be asked of a sample of circular data is whether it suggests that the underlying population is uniformly distributed around the circle, or whether it is concentrated around at least one preferred direction (e.g. a migratory goal or activity phase). We compared the statistical power of five commonly used tests (the Rayleigh test, the V-test, Watson’s test, Kuiper’s test and Rao’s spacing test) across a range of different unimodal scenarios. The V-test showed higher power for symmetrical distributions, Rao’s spacing performed worst for all explored unimodal distributions tested and the remaining three tests showed very similar performance. However, the V-test only applies if the hypothesis is restricted to one (pre-specified) direction of interest. In all other unimodal cases, we recommend using the Rayleigh test. Much less explored is the multimodal case with data concentrated around several directions. We performed power simulations for a variety of multimodal situations, testing the performance of the widely used Rayleigh, Rao’s, Watson, and Kuiper’s tests as well as the more recent Bogdan and Hermans-Rasson tests. Our analyses of alternative statistical methods show that the commonly used tests lack statistical power in many of multimodal cases. Transformation of the raw data (e.g. doubling the angles) can overcome some of the issues, but only in the case of perfect f-fold symmetry. However, the Hermans-Rasson method, which is not yet implemented in any software package, outcompetes the alternative tests (often by substantial margins) in most of the multimodal situations explored. We recommend the wider uptake of the powerful but hitherto neglected Hermans-Rasson method. In summary, we provide guidance for biologists helping them to make decisions when testing circular data for single or multiple departures from uniformity.
Collapse
|