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Lövei GL, Ferrante M. The Use and Prospects of Nonlethal Methods in Entomology. ANNUAL REVIEW OF ENTOMOLOGY 2024; 69:183-198. [PMID: 37669564 DOI: 10.1146/annurev-ento-120220-024402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/07/2023]
Abstract
Arthropods are declining globally, and entomologists ought to be in the forefront of protecting them. However, entomological study methods are typically lethal, and we argue that this makes the ethical status of the profession precarious. Lethal methods are used in most studies, even those that aim to support arthropod conservation. Additionally, almost all collecting methods result in bycatch, and a first step toward less destructive research practices is to minimize bycatch and/or ensure its proper storage and use. In this review, we describe the available suite of nonlethal methods with the aim of promoting their use. We classify nonlethal methods into (a) reuse of already collected material, (b) methods that are damaging but not lethal, (c) methods that modify behavior, and (d) true nonlethal methods. Artificial intelligence and miniaturization will help to extend the nonlethal methodological toolkit, but the need for further method development and testing remains.
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Affiliation(s)
- Gábor L Lövei
- Department of Agroecology, Flakkebjerg Research Centre, Aarhus University, Slagelse, Denmark;
- Hungarian Research Network Anthropocene Ecology Research Group, Debrecen University, Debrecen, Hungary
| | - Marco Ferrante
- Functional Agrobiodiversity, Department of Crop Sciences, University of Göttingen, Germany;
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2
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Allen WJ, Waller LP, Barratt BIP, Dickie IA. Puke or poop? Comparison of regurgitate and faecal samples to infer alpine grasshopper ( Paprides nitidus Hutton) diet in experimental plant communities. Ecol Evol 2023; 13:e10444. [PMID: 37649704 PMCID: PMC10463123 DOI: 10.1002/ece3.10444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 08/08/2023] [Accepted: 08/08/2023] [Indexed: 09/01/2023] Open
Abstract
Characterising plant-herbivore interactions is important to understanding the processes that influence community structure and ecosystem functioning. Traditional methods used to identify plant-herbivore interactions are being superseded by non-destructive molecular approaches that can infer interactions with greater resolution and accuracy from environmental DNA (e.g. faeces and regurgitate). However, few studies have compared the success of using different sample types and whether they provide similar or contrasting information about species' diet. Here we compared the success of DNA amplification and host plant species identification using restriction fragment length polymorphism (RFLP) applied to faecal and regurgitate samples collected from alpine grasshoppers Paprides nitidus Hutton during a grassland community mesocosm experiment. We found that DNA amplification success was 23% and 86% higher for faecal than regurgitate samples from female and male grasshoppers, respectively. In contrast, successful host plant identification using RFLP was 9% higher for regurgitate than faecal samples. The mean number of host plant species identified per sample (1.40) did not differ between sample types or grasshopper sexes. Of the 136 paired faecal-regurgitate samples, just 41% and 74% produced exactly or partially matching host plant identifications, respectively, indicating that different sample types provided complementary information about herbivore diet. Some plant species were more likely to be identified from faecal samples than expected by chance, and we found that this identification bias skewed towards plant species with higher investment in leaf tissue. We conclude that multiple sample types may be required to fully characterise an invertebrate herbivore species' diet.
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Affiliation(s)
- Warwick J. Allen
- Bio‐Protection Research Centre, School of Biological SciencesUniversity of CanterburyChristchurchNew Zealand
- Present address:
Manaaki Whenua ‐ Landcare Research76 Gerald StreetLincoln7608New Zealand
| | | | - Barbara I. P. Barratt
- AgResearch, Invermay Research CentreMosgielNew Zealand
- Department of BotanyUniversity of OtagoDunedinNew Zealand
| | - Ian A. Dickie
- Bio‐Protection Research Centre, School of Biological SciencesUniversity of CanterburyChristchurchNew Zealand
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Guenay-Greunke Y, Trager H, Bohan DA, Traugott M, Wallinger C. Consumer identity but not food availability affects carabid diet in cereal crops. JOURNAL OF PEST SCIENCE 2023; 97:281-296. [PMID: 38223748 PMCID: PMC10784395 DOI: 10.1007/s10340-023-01620-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 04/06/2023] [Accepted: 04/08/2023] [Indexed: 01/16/2024]
Abstract
Understanding trophic interactions in agroecosystems is crucial for harnessing ecosystem services such as pest control, thus enabling a reduction in pesticide use. Carabid beetles (Coleoptera: Carabidae) have the potential to regulate not only insect pests but also weed seeds and slugs. The aim of this study was to investigate the food choice of different carabid species in the experimental setting of a cereal field with varying seed and slug prey availability during the season. In addition to varying food availability, the effects of species identity and season on carabid food choice should also be closely examined. Therefore, the gut contents of 1,120 beetles of eight carabid species were screened for the DNA of plants, aphids, springtails, earthworms and slugs via diagnostic multiplex PCR and a nested metabarcoding approach for plant species identification. Plant DNA was detected far more often (72%) than the various animal prey types (less than 12.5% each). Within the plant detections, 80 weed species were identified in the metabarcoding, with Galinsoga parviflora/quadriradiata (Galinsoga spp.-quickweeds) as the most frequently detected species. Carabid food choice was driven by their species identity and seasonality, while no effect of increased availability of seeds and slugs on their food choice was detected. While weed seeds seem to be an important food source for carabids, their availability does not directly affect the carabid diet. The importance of consumer identity and seasonality highlight the need for a diverse carabid species community for resilient pest control services. Supplementary Information The online version contains supplementary material available at 10.1007/s10340-023-01620-w.
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Affiliation(s)
- Yasemin Guenay-Greunke
- Applied Animal Ecology, Department of Zoology, University of Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
- Institute of Interdisciplinary Mountain Research, IGF, Austrian Academy of Sciences, Technikerstraße 21a, 6020 Innsbruck, Austria
| | - Harald Trager
- Applied Animal Ecology, Department of Zoology, University of Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - David A. Bohan
- Agroécologie, AgroSup Dijon, INRAE, Université Bourgogne Franche-Comté, 21000 Dijon, France
| | - Michael Traugott
- Applied Animal Ecology, Department of Zoology, University of Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Corinna Wallinger
- Applied Animal Ecology, Department of Zoology, University of Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
- Institute of Interdisciplinary Mountain Research, IGF, Austrian Academy of Sciences, Technikerstraße 21a, 6020 Innsbruck, Austria
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Neidel V, Traugott M. Laboratory protocol is important to improve the correlation between target copies and metabarcoding read numbers of seed DNA in ground beetle regurgitates. Sci Rep 2023; 13:1995. [PMID: 36737468 PMCID: PMC9898267 DOI: 10.1038/s41598-023-29019-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 01/30/2023] [Indexed: 02/05/2023] Open
Abstract
DNA metabarcoding is increasingly important for studying feeding interactions, yet it remains unresolved whether reporting read counts or occurrences is to be preferred. To address this issue for gut content samples, basic experimental data on the relationship between read numbers and initial prey DNA amounts and how both change over digestion time is needed. Using regurgitates of the carabid Pseudoophonus rufipes the digestion of Taraxacum officinale seeds was documented for 128 h post-feeding to determine how the number of (1) seed DNA copies and (2) metabarcoding reads change over digestion time, and (3) how they correlate to each other. Additionally, we tested (4) whether PCR cycle-numbers during library preparation affect this correlation. The number of copies and reads both decreased with digestion time, but variation between samples was high. Read and copy numbers correlated when using a library preparation protocol with 35 cycles (R2 = 42.0%), yet a reduction to 30 cycles might significantly improve this correlation, as indicated by additional PCR testing. Our findings show that protocol optimization is important to reduce technical distortions of read numbers in metabarcoding analysis. However, high inter-sample variation, likely due to variable digestive efficiency of individual consumers, can blur the relationship between the amount of food consumed and metabarcoding read numbers.
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Affiliation(s)
- Veronika Neidel
- Applied Animal Ecology Research Unit, Department of Zoology, University of Innsbruck, Technikerstraße 25, 6020, Innsbruck, Austria.
| | - Michael Traugott
- Applied Animal Ecology Research Unit, Department of Zoology, University of Innsbruck, Technikerstraße 25, 6020, Innsbruck, Austria
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Garrison JA, Motwani NH, Broman E, Nascimento FJA. Molecular diet analysis enables detection of diatom and cyanobacteria DNA in the gut of Macoma balthica. PLoS One 2022; 17:e0278070. [PMID: 36417463 PMCID: PMC9683582 DOI: 10.1371/journal.pone.0278070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 11/08/2022] [Indexed: 11/25/2022] Open
Abstract
Detritivores are essential to nutrient cycling, but are often neglected in trophic networks, due to difficulties with determining their diet. DNA analysis of gut contents shows promise of trophic link discrimination, but many unknown factors limit its usefulness. For example, DNA can be rapidly broken down, especially by digestion processes, and DNA provides only a snapshot of the gut contents at a specific time. Few studies have been performed on the length of time that prey DNA can be detected in consumer guts, and none so far using benthic detritivores. Eutrophication, along with climate change, is altering the phytoplankton communities in aquatic ecosystems, on which benthic detritivores in aphotic soft sediments depend. Nutrient-poor cyanobacteria blooms are increasing in frequency, duration, and magnitude in many water bodies, while nutrient-rich diatom spring blooms are shrinking in duration and magnitude, creating potential changes in diet of benthic detritivores. We performed an experiment to identify the taxonomy and quantify the abundance of phytoplankton DNA fragments on bivalve gut contents, and how long these fragments can be detected after consumption in the Baltic Sea clam Macoma balthica. Two common species of phytoplankton (the cyanobacteria Nodularia spumigena or the diatom Skeletonema marinoi) were fed to M. balthica from two regions (from the northern and southern Stockholm archipelago). After removing the food source, M. balthica gut contents were sampled every 24 hours for seven days to determine the number of 23S rRNA phytoplankton DNA copies and when the phytoplankton DNA could no longer be detected by quantitative PCR. We found no differences in diatom 18S rRNA gene fragments of the clams by region, but the southern clams showed significantly more cyanobacteria 16S rRNA gene fragments in their guts than the northern clams. Interestingly, the cyanobacteria and diatom DNA fragments were still detectable by qPCR in the guts of M. balthica one week after removal from its food source. However, DNA metabarcoding of the 23S rRNA phytoplankton gene found in the clam guts showed that added food (i.e. N. spumigena and S. marinoi) did not make up a majority of the detected diet. Our results suggest that these detritivorous clams therefore do not react as quickly as previously thought to fresh organic matter inputs, with other phytoplankton than large diatoms and cyanobacteria constituting the majority of their diet. This experiment demonstrates the viability of using molecular methods to determine feeding of detritivores, but further studies investigating how prey DNA signals can change over time in benthic detritivores will be needed before this method can be widely applicable to both models of ecological functions and conservation policy.
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Affiliation(s)
- Julie A. Garrison
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
- * E-mail:
| | - Nisha H. Motwani
- School of Natural Sciences, Technology and Environmental Studies, Södertörn University, Huddinge, Sweden
- Department of Environmental Science, Stockholm University, Stockholm, Sweden
| | - Elias Broman
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
- Baltic Sea Centre, Stockholm University, Stockholm, Sweden
| | - Francisco J. A. Nascimento
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
- Baltic Sea Centre, Stockholm University, Stockholm, Sweden
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Neidel V, Sint D, Wallinger C, Traugott M. RNA allows identifying the consumption of carrion prey. Mol Ecol Resour 2022; 22:2662-2671. [PMID: 35668675 PMCID: PMC9541938 DOI: 10.1111/1755-0998.13659] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 05/05/2022] [Accepted: 05/17/2022] [Indexed: 11/30/2022]
Abstract
Facultative scavenging by predatory carnivores is a prevalent but frequently underestimated feeding strategy. DNA‐based methods for diet analysis, however, do not allow to distinguish between scavenging and predation, thus, the significance of scavenging on population dynamics and resource partitioning is widely unknown. Here, we present a methodological innovation to differentiate between scavenging and fresh prey consumption using prey RNA as a target molecule. We hypothesized that the rapid post‐mortem breakdown of RNA in prey tissue should lead to a significantly lower detection probability of prey RNA than DNA when carrion rather than fresh prey is consumed. To test this hypothesis, ground beetles (Pseudoophonus rufipes [De Geer]) were offered either fresh or 1‐day‐old dead Drosophila melanogaster fruit flies (carrion). The detectability of prey RNA and DNA in the beetles' regurgitates was assessed with diagnostic Drosophila‐specific RT‐PCR and PCR assays at 0, 6, 12, 24 and 48 h post‐feeding. After fresh fly consumption, prey RNA and DNA were detectable equally well at all times. When carrion prey was consumed, the detection strength of prey RNA immediately after feeding was significantly lower than that of prey DNA and reached zero in most samples within 6 h of digestion. Our findings provide evidence that prey RNA allows distinguishing between the consumption of fresh and scavenged prey, thereby overcoming a long‐known weakness of molecular diet analysis. The assessment of prey RNA offers a generally applicable approach for examining the importance of scavenging in food webs to unravel its functional consequences for populations, communities, and ecosystems.
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Affiliation(s)
- Veronika Neidel
- Applied Animal Ecology, Department of Zoology, University of Innsbruck, Innsbruck, Austria
| | - Daniela Sint
- Applied Animal Ecology, Department of Zoology, University of Innsbruck, Innsbruck, Austria
| | - Corinna Wallinger
- Applied Animal Ecology, Department of Zoology, University of Innsbruck, Innsbruck, Austria
| | - Michael Traugott
- Applied Animal Ecology, Department of Zoology, University of Innsbruck, Innsbruck, Austria
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Pocock MJO, Schmucki R, Bohan DA. Inferring species interactions from ecological survey data: A mechanistic approach to predict quantitative food webs of seed feeding by carabid beetles. Ecol Evol 2021; 11:12858-12871. [PMID: 34594544 PMCID: PMC8462163 DOI: 10.1002/ece3.8032] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 06/30/2021] [Accepted: 07/24/2021] [Indexed: 11/05/2022] Open
Abstract
Ecological networks are valuable for ecosystem analysis but their use is often limited by a lack of data because many types of ecological interaction, for example, predation, are short-lived and difficult to observe or detect. While there are different methods for inferring the presence of interactions, they have rarely been used to predict the interaction strengths that are required to construct weighted, or quantitative, ecological networks.Here, we develop a trait-based approach suitable for inferring weighted networks, that is, with varying interaction strengths. We developed the method for seed-feeding carabid ground beetles (Coleoptera: Carabidae) although the principles can be applied to other species and types of interaction.Using existing literature data from experimental seed-feeding trials, we predicted a per-individual interaction cost index based on carabid and seed size. This was scaled up to the population level to create inferred weighted networks using the abundance of carabids and seeds from empirical samples and energetic intake rates of carabids from the literature. From these weighted networks, we also derived a novel measure of expected predation pressure per seed type per network.This method was applied to existing ecological survey data from 255 arable fields with carabid data from pitfall traps and plant seeds from seed rain traps. Analysis of these inferred networks led to testable hypotheses about how network structure and predation pressure varied among fields.Inferred networks are valuable because (a) they provide null models for the structuring of food webs to test against empirical species interaction data, for example, DNA analysis of carabid gut regurgitates and (b) they allow weighted networks to be constructed whenever we can estimate interactions between species and have ecological census data available. This permits ecological network analysis even at times and in places when interactions were not directly assessed.
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Affiliation(s)
| | - Reto Schmucki
- UK Centre for Ecology & HydrologyWallingford, OxfordshireUK
| | - David A. Bohan
- Agroécologie, AgroSup DijonINRAE, Université de Bourgogne Franche‐ComtéDijonFrance
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Traugott M, Thalinger B, Wallinger C, Sint D. Fish as predators and prey: DNA-based assessment of their role in food webs. JOURNAL OF FISH BIOLOGY 2021; 98:367-382. [PMID: 32441321 PMCID: PMC7891366 DOI: 10.1111/jfb.14400] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 03/26/2020] [Accepted: 05/20/2020] [Indexed: 05/04/2023]
Abstract
Fish are both consumers and prey, and as such part of a dynamic trophic network. Measuring how they are trophically linked, both directly and indirectly, to other species is vital to comprehend the mechanisms driving alterations in fish communities in space and time. Moreover, this knowledge also helps to understand how fish communities respond to environmental change and delivers important information for implementing management of fish stocks. DNA-based methods have significantly widened our ability to assess trophic interactions in both marine and freshwater systems and they possess a range of advantages over other approaches in diet analysis. In this review we provide an overview of different DNA-based methods that have been used to assess trophic interactions of fish as consumers and prey. We consider the practicalities and limitations, and emphasize critical aspects when analysing molecular derived trophic data. We exemplify how molecular techniques have been employed to unravel food web interactions involving fish as consumers and prey. In addition to the exciting opportunities DNA-based approaches offer, we identify current challenges and future prospects for assessing fish food webs where DNA-based approaches will play an important role.
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Affiliation(s)
- Michael Traugott
- Applied Animal Ecology, Department of ZoologyUniversity of InnsbruckInnsbruckAustria
| | - Bettina Thalinger
- Applied Animal Ecology, Department of ZoologyUniversity of InnsbruckInnsbruckAustria
- Centre for Biodiversity Genomics, University of GuelphGuelphCanada
| | - Corinna Wallinger
- Institute of Interdisciplinary Mountain Research, Austrian Academy of ScienceInnsbruckAustria
| | - Daniela Sint
- Applied Animal Ecology, Department of ZoologyUniversity of InnsbruckInnsbruckAustria
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Bohan DA, Schmucki R, Abay AT, Termansen M, Bane M, Charalabidis A, Cong RG, Derocles SA, Dorner Z, Forster M, Gibert C, Harrower C, Oudoire G, Therond O, Young J, Zalai M, Pocock MJ. Designing farmer-acceptable rotations that assure ecosystem service provision in the face of climate change. ADV ECOL RES 2021. [DOI: 10.1016/bs.aecr.2021.01.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Mogren CL, Benítez MS, McCarter K, Boyer F, Lundgren JG. Diverging landscape impacts on macronutrient status despite overlapping diets in managed ( Apis mellifera) and native ( Melissodes desponsa) bees. CONSERVATION PHYSIOLOGY 2020; 8:coaa109. [PMID: 33365131 PMCID: PMC7745716 DOI: 10.1093/conphys/coaa109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 02/20/2020] [Accepted: 11/04/2020] [Indexed: 06/12/2023]
Abstract
Declining pollinator populations worldwide are attributed to multiple stressors, including the loss of quality forage. Habitat management in agricultural areas often targets honey bees (Apis mellifera L.) specifically, with the assumption that native bees will benefit from an 'umbrella species' strategy. We tested this theory using a conservation physiology approach to compare the effects of landscape composition and floral dietary composition on the physiological status of honey bees and Melissodes desponsa in eastern South Dakota, USA. The total glycogen, lipid and protein concentrations were quantified from field collected bees. Next-generation sequencing of the trnL chloroplast gene from bee guts was used to evaluate dietary composition. The effects of landscape and dietary composition on macronutrient concentrations were compared between bee species. As the mean land-use patch area increased, honey bee glycogen levels increased, though M. desponsa experienced a decrease in glycogen. Protein levels decreased in honey bees as the largest patch index, a measure of single patch dominance, increased versus M. desponsa. Lipids in both species were unaffected by the measured landscape variables. Dietary analysis revealed that honey bees foraged preferentially on weedy non-native plant species, while M. desponsa sought out native and rarer species, in addition to utilizing non-native plants. Both species foraged on Asteraceae, Oleaceae and Fabaceae, specifically Melilotus sp. and Medicago sp. Dietary composition was not predictive of the macronutrients measured for either species. Together, these data highlight the management importance of including patch area in conservation recommendations, as bee species may have divergent physiological responses to landscape characteristics. While solitary bees may forage on weedy introduced plants in agricultural areas, robust strategies should also reincorporate native plant species, though they may not be preferred by honey bees, to maximize overall health and diversity of pollinator communities.
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Affiliation(s)
- Christina L Mogren
- Department of Plant and Environmental Protection Sciences, University of Hawai’i at Mānoa, 3050 Maile Way Gilmore 310, Honolulu, HI 96822, USA
| | - María-Soledad Benítez
- Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH 44691, USA
| | - Kevin McCarter
- Department of Experimental Statistics, Louisiana State University, Baton Rouge, LA 70802, USA
| | - Frédéric Boyer
- Laboratoire d’Écologie Alpine, Centre National de la Recherche Scientifique, Université Grenoble Alpes, F-38000 Grenoble, France
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Frei B, Guenay Y, Bohan DA, Traugott M, Wallinger C. Molecular analysis indicates high levels of carabid weed seed consumption in cereal fields across Central Europe. JOURNAL OF PEST SCIENCE 2019; 92:935-942. [PMID: 31178674 PMCID: PMC6528783 DOI: 10.1007/s10340-019-01109-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 03/13/2019] [Accepted: 03/20/2019] [Indexed: 06/09/2023]
Abstract
Carabid beetles are abundant in temperate agroecosystems and can play a pivotal role as biocontrol agents. While there is good knowledge regarding their effects on invertebrate pests in some systems, comparably little is known on the rate of seed feeding under field conditions. Molecular approaches are ideally suited for investigating carabid feeding interactions; to date, however, they have only been applied to animal prey. We sampled adult carabid beetles in organic cereal fields in three regions along a Central European transect. Regurgitates from populations of the three most common species, Poecilus cupreus, Pseudoophonus rufipes and Pterostichus melanarius, were screened for plant DNA, cereal aphids, collembolans and earthworms. The frequency of carabid individuals positive for plant DNA was high (> 70%) and independent of carabid species, sex, region and the time point of sampling. Detections for non-pest and pest prey were comparably lower, with 21.6% for collembolans, 18.1% for earthworms and 4.2% for aphids, respectively. Despite the prolonged detection period of plant DNA in carabid guts, as compared to animal prey, these first results suggest that weed seeds form an important part of the adult carabid diet. It would also lend support to the hypothesis that seed-feeding carabids are biocontrol agents of weeds, with effects of regulation on the weed seedbank that depend on behavioural and contextual factors including carabid species preferences for weed seed species, their life stage and tillage practices.
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Affiliation(s)
- Britta Frei
- Mountain Agriculture Research Unit, Institute of Ecology, University of Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
- Agroecologie, AgroSup Dijon, INRA, Université Bourgogne Franche-Comte, 21000 Dijon, France
| | - Yasemin Guenay
- Mountain Agriculture Research Unit, Institute of Ecology, University of Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
- Institute of Interdisciplinary Mountain Research, IGF, Austrian Academy of Sciences, Technikerstraße 21a, 6020 Innsbruck, Austria
| | - David A. Bohan
- Agroecologie, AgroSup Dijon, INRA, Université Bourgogne Franche-Comte, 21000 Dijon, France
| | - Michael Traugott
- Mountain Agriculture Research Unit, Institute of Ecology, University of Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Corinna Wallinger
- Institute of Interdisciplinary Mountain Research, IGF, Austrian Academy of Sciences, Technikerstraße 21a, 6020 Innsbruck, Austria
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