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Quantifying Southern Pacific Rattlesnake (Crotalus oreganus helleri) Hunting Behavior through Community Science. DIVERSITY 2021. [DOI: 10.3390/d13080349] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
It is increasingly important to study animal behaviors as these are the first responses organisms mount against environmental changes. Rattlesnakes, in particular, are threatened by habitat loss and human activity, and require costly tracking by researchers to quantify the behaviors of wild individuals. Here, we show how photo-vouchered observations submitted by community members can be used to study cryptic predators like rattlesnakes. We utilized two platforms, iNaturalist and HerpMapper, to study the hunting behaviors of wild Southern Pacific Rattlesnakes. From 220 observation photos, we quantified the direction of the hunting coil (i.e., “handedness”), microhabitat use, timing of observations, and age of the snake. With these data, we looked at whether snakes exhibited an ontogenetic shift in behaviors. We found no age differences in coil direction. However, there was a difference in the microhabitats used by juveniles and adults while hunting. We also found that juveniles were most commonly observed during the spring, while adults were more consistently observed throughout the year. Overall, our study shows the potential of using community science to study the behaviors of cryptic predators.
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Diet and Feeding Frequency in the Southwestern Speckled Rattlesnake (Crotalus pyrrhus): Ontogenetic, Sexual, Geographic, and Seasonal Variation. J HERPETOL 2021. [DOI: 10.1670/19-144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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3
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Glaudas X, Rice SE, Clark RW, Alexander GJ. Male energy reserves, mate-searching activities, and reproductive success: alternative resource use strategies in a presumed capital breeder. Oecologia 2020; 194:415-425. [PMID: 32935179 DOI: 10.1007/s00442-020-04755-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 09/08/2020] [Indexed: 11/26/2022]
Abstract
Sexual selection studies often focus on morphological traits that are important only in the later stages of mate acquisition. Comparatively little is known about traits that lead to mate acquisition, such as mate-searching activities. We experimentally manipulated body condition (i.e., the energy reserves) in male puff adders (Bitis arietans) prior to the mating season using supplemental feeding in the field, and used radio-telemetry and DNA paternity analyses to characterize the relationships between male energy reserves, mating activities, and reproductive success. We found that male mobility is a strongly sexually selected trait because males that travelled further in search of females have higher female encounter rates and reproductive success. However, supplemental feeding did not have a significant effect on mating activities or reproductive success, because control snakes compensated by foraging more often during the mating season. The time invested in foraging by control snakes did not come at the costs of decreased mating activities or opportunity compared to fed snakes, because the latter spent the spare time resting. Our experimental field research directly demonstrates the link between male mobility and reproductive success, identifying the ultimate mechanism leading to the evolution of prolonged male mate-searching activities in snakes, and indicates that male puff adders, presumed capital breeders, adjust their breeding tactics according to resource availability.
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Affiliation(s)
- Xavier Glaudas
- School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, P.O. Wits, Johannesburg, 2050, South Africa.
| | - Stephen E Rice
- Department of Biology, San Diego State University, San Diego, CA, 92182, USA
- Department of Natural Sciences, Fairmont State University, Fairmont, WV, 26554, USA
| | - Rulon W Clark
- Department of Biology, San Diego State University, San Diego, CA, 92182, USA
| | - Graham J Alexander
- School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, P.O. Wits, Johannesburg, 2050, South Africa
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Interactive Effects of Food Supplementation and Snake Fungal Disease on Pregnant Pygmy Rattlesnakes and Their Offspring. J HERPETOL 2019. [DOI: 10.1670/18-147] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Rautsaw RM, Hofmann EP, Margres MJ, Holding ML, Strickland JL, Mason AJ, Rokyta DR, Parkinson CL. Intraspecific sequence and gene expression variation contribute little to venom diversity in sidewinder rattlesnakes ( Crotalus cerastes). Proc Biol Sci 2019; 286:20190810. [PMID: 31266424 DOI: 10.1098/rspb.2019.0810] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Traits can evolve rapidly through changes in gene expression or protein-coding sequences. However, these forms of genetic variation can be correlated and changes to one can influence the other. As a result, we might expect traits lacking differential expression to preferentially evolve through changes in protein sequences or morphological adaptation. Given the lack of differential expression across the distribution of sidewinder rattlesnakes ( Crotalus cerastes), we tested this hypothesis by comparing the coding regions of genes expressed in the venom gland transcriptomes and fang morphology. We calculated Tajima's D and FST across four populations comparing toxin and nontoxin loci. Overall, we found little evidence of directional selection or differentiation between populations, suggesting that changes to protein sequences do not underlie the evolution of sidewinder venom or that toxins are under extremely variant selection pressures. Although low-expression toxins do not have higher sequence divergence between populations, they do have more standing variation on which selection can act. Additionally, we found significant differences in fang length among populations. The lack of differential expression and sequence divergence suggests sidewinders-given their generalist diet, moderate gene flow and environmental variation-are under stabilizing selection which functions to maintain a generalist phenotype. Overall, we demonstrate the importance of examining the relationship between gene expression and protein-coding changes to understand the evolution of complex traits.
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Affiliation(s)
- Rhett M Rautsaw
- 1 Department of Biological Sciences, Clemson University , Clemson, SC 29634 , USA
| | - Erich P Hofmann
- 1 Department of Biological Sciences, Clemson University , Clemson, SC 29634 , USA
| | - Mark J Margres
- 1 Department of Biological Sciences, Clemson University , Clemson, SC 29634 , USA
| | - Matthew L Holding
- 1 Department of Biological Sciences, Clemson University , Clemson, SC 29634 , USA.,3 Department of Biological Science, Florida State University , Tallahassee, FL 32306 , USA
| | - Jason L Strickland
- 1 Department of Biological Sciences, Clemson University , Clemson, SC 29634 , USA
| | - Andrew J Mason
- 1 Department of Biological Sciences, Clemson University , Clemson, SC 29634 , USA
| | - Darin R Rokyta
- 3 Department of Biological Science, Florida State University , Tallahassee, FL 32306 , USA
| | - Christopher L Parkinson
- 1 Department of Biological Sciences, Clemson University , Clemson, SC 29634 , USA.,2 Department of Forestry and Environmental Conservation, Clemson University , Clemson, SC 29634 , USA
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Tetzlaff SJ, Carter ET, DeGregorio BA, Ravesi MJ, Kingsbury BA. To forage, mate, or thermoregulate: Influence of resource manipulation on male rattlesnake behavior. Ecol Evol 2017; 7:6606-6613. [PMID: 28861261 PMCID: PMC5574792 DOI: 10.1002/ece3.3193] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 05/30/2017] [Accepted: 05/31/2017] [Indexed: 11/11/2022] Open
Abstract
Male animals should preferentially allocate their time to performing activities that promote enhancing reproductive opportunity, but the need to acquire resources for growth and survival may compete with those behaviors in the short term. Thus, behaviors which require differing movement patterns such as ambushing prey and actively searching for mates can be mutually exclusive. Consequently, males that succeed at foraging could invest greater time and energy into mate searching. We radio-tracked sixteen male massasauga rattlesnakes (Sistrurus catenatus) and supplemented the diets of half the snakes with mice across an active season. We tested the predictions that reduced foraging needs would allow fed snakes to move (i.e., mate search) more, but that they would consequently be stationary to thermoregulate less, than unfed controls. Contrary to our first prediction, we found no evidence that fed snakes altered their mate searching behavior compared to controls. However, we found controls maintained higher body temperatures than fed snakes during the breeding season, perhaps because fed snakes spent less time in exposed ambush sites. Fed snakes had higher body condition scores than controls when the breeding season ended. Our results suggest the potential costs incurred by devoting time to stationary foraging may be outweighed by the drive to increase mating opportunities. Such instances may be especially valuable for massasaugas and other temperate reptiles that can remain inactive for upwards of half their lives or longer in some cases, and for female rattlesnakes that generally exhibit biennial or more protracted reproductive cycles.
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Affiliation(s)
- Sasha J Tetzlaff
- Department of Natural Resources and Environmental Sciences University of Illinois at Urbana-Champaign Urbana IL USA
| | - Evin T Carter
- Department of Ecology and Evolutionary Biology University of Tennessee Knoxville TN USA
| | - Brett A DeGregorio
- Department of Natural Resources and Environmental Sciences University of Illinois at Urbana-Champaign Urbana IL USA.,US Army ERDC-CERL Champaign IL USA
| | - Michael J Ravesi
- Michigan Department of Military and Veterans Affairs Grayling MI USA
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Webber MM, Jezkova T, Rodríguez-Robles JA. Feeding Ecology of Sidewinder Rattlesnakes, Crotalus cerastes (Viperidae). HERPETOLOGICA 2016. [DOI: 10.1655/herpetologica-d-15-00031.1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Michael M. Webber
- School of Life Sciences, University of Nevada, Las Vegas, 4505 Maryland Parkway, Las Vegas, NV 89154, USA
| | - Tereza Jezkova
- School of Life Sciences, University of Nevada, Las Vegas, 4505 Maryland Parkway, Las Vegas, NV 89154, USA
| | - Javier A. Rodríguez-Robles
- School of Life Sciences, University of Nevada, Las Vegas, 4505 Maryland Parkway, Las Vegas, NV 89154, USA
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Food supplementation affects the foraging ecology of a low-energy, ambush-foraging snake. Behav Ecol Sociobiol 2016. [DOI: 10.1007/s00265-016-2239-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Hoss SK, Garcia MJ, Earley RL, Clark RW. Fine-scale hormonal patterns associated with birth and maternal care in the cottonmouth (Agkistrodon piscivorus), a North American pitviper snake. Gen Comp Endocrinol 2014; 208:85-93. [PMID: 25169835 DOI: 10.1016/j.ygcen.2014.08.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 08/10/2014] [Accepted: 08/17/2014] [Indexed: 01/06/2023]
Abstract
Steroid hormones regulate many aspects of reproductive physiology and behavior, including parental care. Reptiles display a variety of egg- and neonate-directed parental behaviors, yet few studies have addressed their endocrine correlates. Viviparous female pitvipers remain at the birth site with their young for one to two weeks until neonates complete their first shed cycle ('ecdysis'). To study possible relationships between steroid hormones and these behaviors, we conducted a captive study on wild-caught pregnant cottonmouths. Females were divided into two treatment groups: Maternal Attendance (MA) - females were allowed a maternal attendance period, where neonates were left with the mother until they completed ecdysis and then were removed; Separated (SE) - females had their neonates removed within 24h of birth. Serial blood samples were collected from MA females at various points during and after attendance; SE females had samples collected on a similar temporal schedule. Plasma levels of progesterone (P), estradiol (E2), testosterone (T), and corticosterone (CORT) were measured in all samples. We did not find a difference in the overall pattern of P, E2, or T between MA and SE females; however, MA females exhibited a significant peak in CORT on the day that neonates shed that was not observed in SE females. It is possible that the elevated CORT observed in MA females was stimulated by increased activity and/or changing chemical cues of shedding neonates. Based on evidence that free-ranging pitvipers cease MA when all offspring complete ecdysis, we hypothesize that CORT has a role in signaling mothers to terminate care and disperse.
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Affiliation(s)
- Shannon K Hoss
- Department of Biology, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA.
| | - Mark J Garcia
- Department of Biological Sciences, The University of Alabama, 300 Hackberry Lane, Box 870344, Tuscaloosa, AL 35487, USA.
| | - Ryan L Earley
- Department of Biological Sciences, The University of Alabama, 300 Hackberry Lane, Box 870344, Tuscaloosa, AL 35487, USA.
| | - Rulon W Clark
- Department of Biology, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA.
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Hoss SK, Clark RW. Mother Cottonmouths (Agkistrodon piscivorus) Alter Their Antipredator Behavior in the Presence of Neonates. Ethology 2014. [DOI: 10.1111/eth.12265] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Shannon K. Hoss
- Department of Biology; San Diego State University; San Diego CA USA
| | - Rulon W. Clark
- Department of Biology; San Diego State University; San Diego CA USA
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Webber MM, Rodríguez-Robles JA. Reproductive tradeoff limits the predatory efficiency of female Arizona Bark Scorpions (Centruroides sculpturatus). BMC Evol Biol 2013; 13:197. [PMID: 24034444 PMCID: PMC3868313 DOI: 10.1186/1471-2148-13-197] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 09/06/2013] [Indexed: 11/10/2022] Open
Abstract
Background Life history tradeoffs may result from temporal and physiological constraints intrinsic to an organism. When faced with limited time and energy, compromises occur and these resources are allocated among essential activities, such as body growth, maintenance, foraging, mating, and offspring care. We investigated potential tradeoffs that may occur between reproductive activities and feeding performance in female Arizona Bark Scorpions (Centruroides sculpturatus) by comparing the time taken to capture prey between non-reproductive and reproductive females (gravid females and females exhibiting maternal care, i.e. carrying offspring on their backs). Results Gravid females were as efficient at catching prey as non-gravid females. To control for variation in the duration of the maternal care period, we removed all offspring from all post-parturient females after 5 days. Brooding females and females 24 hours following offspring removal (FOR) did not successfully capture prey within the 900-second trial period. Twenty-eight days FOR, females caught prey faster than females displaying maternal care and females 24 hours FOR, but were not as efficient at catching prey as non-gravid and gravid females. When pursuing prey, C. sculpturatus exhibiting maternal care used an active foraging strategy more frequently than non-gravid, gravid, and females 28 days FOR. In contrast, non-gravid, gravid, and females 28 days FOR used active and ambush foraging with similar frequency. Conclusions Our data suggest that reproduction does not significantly reduce the predatory efficiency of gravid C. sculpturatus, and that these females can cope with increasing body mass and the physiological costs of gestation. However, the observation that brooding females and females 24 hours FOR did not catch prey within the trial period indicates that maternal care significantly reduces predatory efficiency in these scorpions. Females 28 days FOR were still not as efficient at catching prey as non-gravid and gravid females, suggesting that reproductive costs extend for at least 4 weeks after the end of the maternal care period. Preferential use of an active foraging strategy by brooding females may increase prey encounter rates, allowing the scorpions to more rapidly replenish energy reserves depleted during reproduction. However, active foraging may be energetically costly and increase predation risk for brooding females. Our findings regarding antagonistic interactions between reproduction and feeding in female C. sculpturatus demonstrate the pervasive nature of reproductive costs for viviparous females, and may provide insight on factors that influence the diversity of reproductive strategies observed in nature.
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Affiliation(s)
- Michael M Webber
- School of Life Sciences, University of Nevada, Las Vegas, 4505 S, Maryland Parkway, Las Vegas, Nevada 89154-4004, USA.
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Schuett GW, Repp RA, Amarello M, Smith CF. Unlike most vipers, female rattlesnakes(Crotalus atrox)continue to hunt and feed throughout pregnancy. J Zool (1987) 2012. [DOI: 10.1111/j.1469-7998.2012.00969.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - R. A. Repp
- National Optical Astronomy Observatory; Tucson; AZ; USA
| | - M. Amarello
- School of Life Sciences; Arizona State University; Tempe; AZ; USA
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