1
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Haug C, Haug JT, Haug GT, Müller P, Zippel A, Kiesmüller C, Gauweiler J, Hörnig MK. Fossils in Myanmar amber demonstrate the diversity of anti-predator strategies of Cretaceous holometabolan insect larvae. iScience 2024; 27:108621. [PMID: 38213619 PMCID: PMC10783632 DOI: 10.1016/j.isci.2023.108621] [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: 06/23/2023] [Revised: 09/14/2023] [Accepted: 11/30/2023] [Indexed: 01/13/2024] Open
Abstract
Holometabolan larvae are a major part of the animal biomass and an important food source for many animals. Many larvae evolved anti-predator strategies and some of these can even be recognized in fossils. A Lagerstätte known for well-preserved holometabolan larvae is the approximately 100-million-year-old Kachin amber from Myanmar. Fossils can not only allow to identify structural defensive specializations, but also lifestyle and even behavioral aspects. We review here the different defensive strategies employed by various holometabolan larvae found in Kachin amber, also reporting new cases of a leaf-mining hymenopteran caterpillar and a hangingfly caterpillar with extensive spines. This overview demonstrates that already 100 million years ago many modern strategies had already evolved in multiple lineages, but also reveals some cases of now extinct strategies. The repetitive independent evolution of similar strategies in distantly related lineages indicates that several strategies evolved convergently as a result of similar selective pressures.
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Affiliation(s)
- Carolin Haug
- Ludwig-Maximilians-Universität München (LMU Munich), Biocenter, Großhaderner Str. 2, 82152 Planegg-Martinsried, Germany
- GeoBio-Center at LMU, Richard-Wagner-Str. 10, 80333 München, Germany
| | - Joachim T. Haug
- Ludwig-Maximilians-Universität München (LMU Munich), Biocenter, Großhaderner Str. 2, 82152 Planegg-Martinsried, Germany
- GeoBio-Center at LMU, Richard-Wagner-Str. 10, 80333 München, Germany
| | - Gideon T. Haug
- Ludwig-Maximilians-Universität München (LMU Munich), Biocenter, Großhaderner Str. 2, 82152 Planegg-Martinsried, Germany
| | | | - Ana Zippel
- Ludwig-Maximilians-Universität München (LMU Munich), Biocenter, Großhaderner Str. 2, 82152 Planegg-Martinsried, Germany
| | - Christine Kiesmüller
- University of Greifswald, Zoological Institute and Museum, Cytology and Evolutionary Biology, Soldmannstr. 23, 17489 Greifswald, Germany
| | - Joshua Gauweiler
- University of Greifswald, Zoological Institute and Museum, Cytology and Evolutionary Biology, Soldmannstr. 23, 17489 Greifswald, Germany
| | - Marie K. Hörnig
- University of Greifswald, Zoological Institute and Museum, Cytology and Evolutionary Biology, Soldmannstr. 23, 17489 Greifswald, Germany
- University Medical Center Rostock, Medical Biology and Electron Microscopy Center, Strempelstr. 14, 18057 Rostock, Germany
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2
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Lawrence JP, Rojas B, Blanchette A, Saporito RA, Mappes J, Fouquet A, Noonan BP. Linking Predator Responses to Alkaloid Variability in Poison Frogs. J Chem Ecol 2023; 49:195-204. [PMID: 36854928 DOI: 10.1007/s10886-023-01412-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 02/11/2023] [Accepted: 02/15/2023] [Indexed: 03/02/2023]
Abstract
Many chemically-defended/aposematic species rely on diet for sequestering the toxins with which they defend themselves. This dietary acquisition can lead to variable chemical defenses across space, as the community composition of chemical sources is likely to vary across the range of (an aposematic) species. We characterized the alkaloid content of two populations of the Dyeing Poison Frog (Dendrobates tinctorius) in northeastern French Guiana. Additionally, we conducted unpalatability experiments with naive predators, Blue Tits (Cyanistes caeruleus), using whole-skin secretion cocktails to assess how a model predator would respond to the defense of individuals from each population. While there was some overlap between the two D. tinctorius populations in terms of alkaloid content, our analysis revealed that these two populations are markedly distinct in terms of overall alkaloid profiles. Predator responses to skin secretions differed between the populations. We identified 15 candidate alkaloids (including three previously undescribed) in seven classes that are correlated with predator response in one frog population. We describe alkaloid profile differences between populations for D. tinctorius and provide a novel method for assessing unpalatability of skin secretions and identifying which toxins may contribute to the predator response. In one population, our results suggest 15 alkaloids that are implicated in predator aversive response. This method is the first step in identifying the causal link between alkaloids and behavioral responses of predators, and thus makes sense of how varying alkaloid combinations are capable of eliciting consistent behavioral responses, and eventually driving evolutionary change in aposematic characters (or characteristics).
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Affiliation(s)
- J P Lawrence
- Department of Biology, University of Mississippi, University, MS, 38677, USA. .,Lyman Briggs College, Michigan State University, East Lansing, MI, 48825, USA.
| | - Bibiana Rojas
- Department of Biology and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland.,Konrad Lorenz Institute of Ethology, Department of Interdisciplinary Life Sciences, University of Veterinary Medicine Vienna, Savoyenstraße 1, 1160, Vienna, Austria
| | - Annelise Blanchette
- Department of Biology, John Carroll University, University Heights, OH, 44118, USA.,Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA, 70118, USA
| | - Ralph A Saporito
- Department of Biology, John Carroll University, University Heights, OH, 44118, USA
| | - Johanna Mappes
- Department of Biology and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland.,Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, Helsinki University, Helsinki, Finland
| | - Antoine Fouquet
- Laboratoire Evolution et Diversité Biologique, UMR5174, Université Paul Sabatier, 31062, Toulouse Cedex 9, France
| | - Brice P Noonan
- Department of Biology, University of Mississippi, University, MS, 38677, USA
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3
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Petschenka G, Halitschke R, Züst T, Roth A, Stiehler S, Tenbusch L, Hartwig C, Gámez JFM, Trusch R, Deckert J, Chalušová K, Vilcinskas A, Exnerová A. Sequestration of defenses against predators drives specialized host plant associations in preadapted milkweed bugs (Heteroptera: Lygaeinae). Am Nat 2022; 199:E211-E228. [DOI: 10.1086/719196] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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4
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Gonzalez M, Palacios-Rodriguez P, Hernandez-Restrepo J, González-Santoro M, Amézquita A, Brunetti AE, Carazzone C. First characterization of toxic alkaloids and volatile organic compounds (VOCs) in the cryptic dendrobatid Silverstoneia punctiventris. Front Zool 2021; 18:39. [PMID: 34446035 PMCID: PMC8390233 DOI: 10.1186/s12983-021-00420-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 06/14/2021] [Indexed: 11/24/2022] Open
Abstract
Background Poison frogs are known for the outstanding diversity of alkaloid-based chemical defences with promising therapeutic applications. However, current knowledge about chemical defences in Dendrobatoidea superfamily has two sources of bias. First, cryptic, brown-colored species have been neglected in comparison to those conspicuously colored, and second, there has been little interest in characterizing metabolites other than alkaloids mediating defensive functions. In an effort to contribute to fill the gap of knowledge about cryptic species and broadening the spectrum of compounds analyzed we have applied head-space solid phase microextraction coupled to gas chromatography and mass spectrometry (HS-SPME/GC-MS) for extracting amphibian alkaloids and volatile organic compounds (VOCs) from Silverstoneia punctiventris. Results Using the skin from 8 specimens in 4 biological replicates we have found 33 different compounds. Twenty of them were classified as VOCs into 15 chemical classes including alkanes, alcohols, carbonyl compounds, methylpyridines, benzothiazoles, N-alkylpyrrolidines, pyrazines, and sesquiterpenoids, some of which were previously reported as repellents, defence compounds or defence pheromones in other organisms, and as sex pheromones in a treefrog. Interestingly, six of the remaining compounds were identified as alkaloids previously reported in other toxic/unpalatable dendrobatid frogs. Conclusions This is the first report of alkaloids and VOCs found in the Silverstoneia genus, which has been assumed for decades as non-chemically defended. This study establishes HS-SPME/GC-MS as a new application for a simultaneous approach to amphibian alkaloids and VOCs in poison frogs while opens up new research questions to assess the co-occurrence of both type of compounds and to investigate the evolutionary significance of a defence gradient that includes olfactory avoidance, unpalatability, and toxicity in dendrobatids. In addition, our results show that amphibian alkaloids could have a dual function (olfactory at distance, taste by contact) never explored before neither in Silverstonaeia nor in any other dendrobatid species. Supplementary Information The online version contains supplementary material available at 10.1186/s12983-021-00420-1.
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Affiliation(s)
- Mabel Gonzalez
- Department of Chemistry, Universidad de los Andes, Bogotá, AA, 4976, Colombia
| | | | | | | | - Adolfo Amézquita
- Department of Biological Sciences, Universidad de los Andes, Bogotá, AA, 4976, Colombia
| | - Andrés E Brunetti
- Laboratorio de Genética Evolutiva, Instituto de Biología Subtropical (CONICET - UNaM), Facultad de Ciencias Exactas, Universidad Nacional de Misiones, N3300, Posadas, Argentina.,Departamento de Ciências Biomoleculares, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, 14040-903, Ribeirão Preto, SP, Brazil
| | - Chiara Carazzone
- Department of Chemistry, Universidad de los Andes, Bogotá, AA, 4976, Colombia.
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5
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Song W, Lee SI, Jablonski PG. Evolution of switchable aposematism: insights from individual-based simulations. PeerJ 2020; 8:e8915. [PMID: 32309047 PMCID: PMC7153555 DOI: 10.7717/peerj.8915] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 03/15/2020] [Indexed: 11/20/2022] Open
Abstract
Some defended prey animals can switch on their normally hidden aposematic signals. This switching may occur in reaction to predators’ approach (pre-attack signals) or attack (post-attack signals). Switchable aposematism has been relatively poorly studied, but we can expect that it might bring a variety of benefits to an aposmetic organism. First, the switching could startle the predators (deimatism). Second, it could facilitate aversive learning. Third, it could minimize exposure or energetic expense, as the signal can be switched off. These potential benefits might offset costs of developing, maintaining and utilizing the switchable traits. Here we focused on the third benefit of switchability, the cost-saving aspect, and developed an individual-based computer simulation of predators and prey. In 88,128 model runs, we observed evolution of permanent, pre-attack, or post-attack aposematic signals of varying strength. We found that, in general, the pre-attack switchable aposematism may require moderate predator learning speed, high basal detectability, and moderate to high signal cost. On the other hand, the post-attack signals may arise under slow predator learning, low basal detectability and high signal cost. When predator population turnover is fast, it may lead to evolution of post-attack aposematic signals that are not conforming to the above tendency. We also suggest that a high switching cost may exert different selection pressure on the pre-attack than the post-attack switchable strategies. To our knowledge, these are the first theoretical attempts to systematically explore the evolution of switchable aposematism relative to permanent aposematism in defended prey. Our simulation model is capable of addressing additional questions beyond the scope of this article, and we open the simulation software, program manual and source code for free public use.
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Affiliation(s)
- Woncheol Song
- Laboratory of Behavioral Ecology and Evolution, School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Sang-im Lee
- School of Undergraduate Studies, Daegu-Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Piotr G. Jablonski
- Laboratory of Behavioral Ecology and Evolution, School of Biological Sciences, Seoul National University, Seoul, South Korea
- Museum and Institute of Zoology, Polish Academy of Sciences, Warsaw, Poland
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6
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Wang L, Cornell SJ, Speed MP. The evolution of variance in sequential defences. J Theor Biol 2019; 462:194-209. [PMID: 30300647 DOI: 10.1016/j.jtbi.2018.10.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 09/06/2018] [Accepted: 10/03/2018] [Indexed: 01/14/2023]
Abstract
The defences used by organisms against predators display a great degree of variability. Defence phenotypes can differ substantially among individuals of the same species, and a single individual can itself deploy a variety of defences. Here, we use a mathematical model that includes mutation and selection to understand the evolutionary origin of this variability in a population of a species that deploys defences sequentially ("first" and "second" defences). Typically, the first defence evolves to have lower variance, i.e. appears more closely accumulated around the ideal phenotype, than the second defence (even when the breaching the first defence incurs more fitness loss than breaching the second defence with the other parameters the same for both defences). However, if the first defence is much less effective in repelling predators, or is much less tolerant of deviation from the ideal phenotype, then the first defence can evolve to have higher variance than the second. Other factors like mutation strength and the losses in the fitness when each defence fails also influence the defence variance. Larger mutation rate incurs larger equilibrium variances, and when the comparative importance in fitness of one defence increases, then the ratio between the variances of this defence and the other defence decreases. Sequentially acting defences are found in many organisms, so we encourage empirical research to test our theoretical predictions.
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Affiliation(s)
- Lingzi Wang
- Department of Evolution, Ecology and Behaviour, Institute of Integrative Biology, Faculty of Health & Life Sciences, University of Liverpool, Liverpool L69 7ZB, UK.
| | - Stephen J Cornell
- Department of Evolution, Ecology and Behaviour, Institute of Integrative Biology, Faculty of Health & Life Sciences, University of Liverpool, Liverpool L69 7ZB, UK
| | - Michael P Speed
- Department of Evolution, Ecology and Behaviour, Institute of Integrative Biology, Faculty of Health & Life Sciences, University of Liverpool, Liverpool L69 7ZB, UK
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7
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Best R, Ruxton GD, Gardner A. Intragroup and intragenomic conflict over chemical defense against predators. Ecol Evol 2018; 8:3322-3329. [PMID: 29607027 PMCID: PMC5869269 DOI: 10.1002/ece3.3926] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 01/13/2018] [Accepted: 01/23/2018] [Indexed: 01/24/2023] Open
Abstract
Insects are often chemically defended against predators. There is considerable evidence for a group-beneficial element to their defenses, and an associated potential for individuals to curtail their own investment in costly defense while benefitting from the investments of others, termed "automimicry." Although females in chemically defended taxa often lay their eggs in clusters, leading to siblings living in close proximity, current models of automimicry have neglected kin-selection effects, which may be expected to curb the evolution of such selfishness. Here, we develop a general theory of automimicry that explicitly incorporates kin selection. We investigate how female promiscuity modulates intragroup and intragenomic conflicts overinvestment into chemical defense, finding that individuals are favored to invest less than is optimal for their group, and that maternal-origin genes favor greater investment than do paternal-origin genes. We translate these conflicts into readily testable predictions concerning gene expression patterns and the phenotypic consequences of genomic perturbations, and discuss how our results may inform gene discovery in relation to economically important agricultural products.
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Affiliation(s)
- Rebekah Best
- School of Biology University of St Andrews St Andrews UK
| | | | - Andy Gardner
- School of Biology University of St Andrews St Andrews UK
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8
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Landová E, Hotová Svádová K, Fuchs R, Štys P, Exnerová A. The effect of social learning on avoidance of aposematic prey in juvenile great tits (Parus major). Anim Cogn 2017. [PMID: 28639012 DOI: 10.1007/s10071-017-1106-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Social learning plays an important role in acquiring new foraging skills and food preferences in many bird species but its potential role in learning to avoid aposematic prey has never been studied. We tested the effect of social learning on the acquisition of avoidance of aposematic insect prey (firebug Pyrrhocoris apterus; Heteroptera) in juvenile, hand-reared great tits (Parus major). Behaviour towards aposematic prey was compared between two groups of birds: (1) the observers that were, prior to encounter with firebugs, allowed to watch the experienced conspecific demonstrator repeatedly refuse to attack the prey, and (2) the control birds that lacked this opportunity. Observing an experienced demonstrator was not sufficient for learning complete avoidance, because birds from both groups attacked at least the first firebug they had encountered in avoidance training. However, the opportunity to observe the avoidance behaviour of another bird significantly increased the rate of subsequent individual learning of observers in comparison with control birds. Social learning also decreased mortality of firebugs killed by the birds during the avoidance learning. Socially enhanced learning to avoid aposematic prey might be a mechanism important especially for naive juvenile birds learning from their parents, but it could also enhance learning in adults from their more experienced flock mates. Because social learning of avoidance may also lead to decreased mortality of aposematic prey, its effect should be taken into account in scenarios considering evolution and maintenance of prey warning signals.
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Affiliation(s)
- Eva Landová
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, 128 44, Prague 2, Czech Republic
| | - Kateřina Hotová Svádová
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, 128 44, Prague 2, Czech Republic
| | - Roman Fuchs
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, 128 44, Prague 2, Czech Republic
| | - Pavel Štys
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, 128 44, Prague 2, Czech Republic
| | - Alice Exnerová
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, 128 44, Prague 2, Czech Republic.
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9
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Parameterising a public good: how experiments on predation can be used to predict cheat frequencies. Evol Ecol 2016. [DOI: 10.1007/s10682-016-9851-6] [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]
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10
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Paul SC, Pell JK, Blount JD. Reproduction in Risky Environments: The Role of Invasive Egg Predators in Ladybird Laying Strategies. PLoS One 2015; 10:e0139404. [PMID: 26488753 PMCID: PMC4619405 DOI: 10.1371/journal.pone.0139404] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 09/12/2015] [Indexed: 12/04/2022] Open
Abstract
Reproductive environments are variable and the resources available for reproduction are finite. If reliable cues about the environment exist, mothers can alter offspring phenotype in a way that increases both offspring and maternal fitness (‘anticipatory maternal effects’—AMEs). Strategic use of AMEs is likely to be important in chemically defended species, where the risk of offspring predation may be modulated by maternal investment in offspring toxin level, albeit at some cost to mothers. Whether mothers adjust offspring toxin levels in response to variation in predation risk is, however, unknown, but is likely to be important when assessing the response of chemically defended species to the recent and pervasive changes in the global predator landscape, driven by the spread of invasive species. Using the chemically defended two-spot ladybird, Adalia bipunctata, we investigated reproductive investment, including egg toxin level, under conditions that varied in the degree of simulated offspring predation risk from larval harlequin ladybirds, Harmonia axyridis. H. axyridis is a highly voracious alien invasive species in the UK and a significant intraguild predator of A. bipunctata. Females laid fewer, larger egg clusters, under conditions of simulated predation risk (P+) than when predator cues were absent (P-), but there was no difference in toxin level between the two treatments. Among P- females, when mean cluster size increased there were concomitant increases in both the mass and toxin concentration of eggs, however when P+ females increased cluster size there was no corresponding increase in egg toxin level. We conclude that, in the face of offspring predation risk, females either withheld toxins or were physiologically constrained, leading to a trade-off between cluster size and egg toxin level. Our results provide the first demonstration that the risk of offspring predation by a novel invasive predator can influence maternal investment in toxins within their offspring.
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Affiliation(s)
- Sarah C. Paul
- Centre for Ecology & Conservation, College of Life & Environmental Sciences, University of Exeter, Penryn Campus, Cornwall, United Kingdom
| | - Judith K. Pell
- J. K. Pell Consulting, Luton, Bedfordshire, United Kingdom
| | - Jonathan D. Blount
- Centre for Ecology & Conservation, College of Life & Environmental Sciences, University of Exeter, Penryn Campus, Cornwall, United Kingdom
- * E-mail:
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11
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Flores EE, Stevens M, Moore AJ, Rowland HM, Blount JD. Body size but not warning signal luminance influences predation risk in recently metamorphosed poison frogs. Ecol Evol 2015; 5:4603-16. [PMID: 26668726 PMCID: PMC4670055 DOI: 10.1002/ece3.1731] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 08/19/2015] [Accepted: 08/22/2015] [Indexed: 01/05/2023] Open
Abstract
During early development, many aposematic species have bright and conspicuous warning appearance, but have yet to acquire chemical defenses, a phenotypic state which presumably makes them vulnerable to predation. Body size and signal luminance in particular are known to be sensitive to variation in early nutrition. However, the relative importance of these traits as determinants of predation risk in juveniles is not known. To address this question, we utilized computer‐assisted design (CAD) and information on putative predator visual sensitivities to produce artificial models of postmetamorphic froglets that varied in terms of body size and signal luminance. We then deployed the artificial models in the field and measured rates of attack by birds and unknown predators. Our results indicate that body size was a significant predictor of artificial prey survival. Rates of attack by bird predators were significantly higher on smaller models. However, predation by birds did not differ between artificial models of varying signal luminance. This suggests that at the completion of metamorphosis, smaller froglets may be at a selective disadvantage, potentially because predators can discern they have relatively low levels of chemical defense compared to larger froglets. There is likely to be a premium on efficient foraging, giving rise to rapid growth and the acquisition of toxins from dietary sources in juvenile poison frogs.
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Affiliation(s)
- Eric E Flores
- Centre for Ecology and Conservation College of Life & Environmental Sciences University of Exeter Penryn UK ; Sistema Nacional de Investigacion de Panama (SNI) Panama
| | - Martin Stevens
- Centre for Ecology and Conservation College of Life & Environmental Sciences University of Exeter Penryn UK
| | - Allen J Moore
- Centre for Ecology and Conservation College of Life & Environmental Sciences University of Exeter Penryn UK ; Department of Genetics University of Georgia 30602 Athens Georgia
| | | | - Jonathan D Blount
- Centre for Ecology and Conservation College of Life & Environmental Sciences University of Exeter Penryn UK
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12
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Summers K, Speed MP, Blount JD, Stuckert AMM. Are aposematic signals honest? A review. J Evol Biol 2015; 28:1583-99. [DOI: 10.1111/jeb.12676] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 06/08/2015] [Accepted: 06/11/2015] [Indexed: 01/22/2023]
Affiliation(s)
- K. Summers
- Department of Biology; East Carolina University; Greenville NC USA
| | - M. P. Speed
- Department of Evolution, Ecology, and Behaviour; University of Liverpool; Liverpool UK
| | - J. D. Blount
- Centre for Ecology and Conservation, Biosciences; University of Exeter; Penryn UK
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13
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Ecological pharmacodynamics: prey toxin evolution depends on the physiological characteristics of predators. Anim Behav 2014. [DOI: 10.1016/j.anbehav.2014.09.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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14
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Stuckert AMM, Saporito RA, Venegas PJ, Summers K. Alkaloid defenses of co-mimics in a putative Müllerian mimetic radiation. BMC Evol Biol 2014; 14:76. [PMID: 24707851 DOI: 10.1186/1471-2148-14-76] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 03/31/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Polytypism in aposematic species is unlikely according to theory, but commonly seen in nature. Ranitomeya imitator is a poison frog species exhibiting polytypic mimicry of three congeneric model species (R. fantastica, R. summersi, and two morphs of R. variabilis) across four allopatric populations (a "mimetic radiation"). In order to investigate chemical defenses in this system, a key prediction of Müllerian mimicry, we analyzed the alkaloids of both models and mimics from four allopatric populations. RESULTS In this study we demonstrate distinct differences in alkaloid profiles between co-mimetic species within allopatric populations. We further demonstrate that R. imitator has a greater number of distinct alkaloid types than the model species and more total alkaloids in all but one population. CONCLUSIONS Given that R. imitator is the more abundant species in these populations, R. imitator is likely driving the majority of predator-learned avoidance in these complexes. The success of Ranitomeya imitator as a putative advergent mimic may be a direct result of differences in alkaloid sequestration. Furthermore, we propose that automimicry within co-mimetic species is an important avenue of research.
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Affiliation(s)
- Adam M M Stuckert
- Department of Biology, East Carolina University, 1000 E, Fifth St, Greenville, NC 27858, USA.
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15
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Flores EE, Stevens M, Moore AJ, Blount JD. Diet, development and the optimization of warning signals in post‐metamorphic green and black poison frogs. Funct Ecol 2013. [DOI: 10.1111/1365-2435.12084] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Eric E. Flores
- Centre for Ecology and Conservation College of Life & Environmental Sciences University of Exeter Cornwall Campus Penryn TR10 9EZ UK
| | - Martin Stevens
- Department of Zoology University of Cambridge Downing Street Cambridge CB2 3EJ UK
| | - Allen J. Moore
- Centre for Ecology and Conservation College of Life & Environmental Sciences University of Exeter Cornwall Campus Penryn TR10 9EZ UK
- Department of Genetics University of Georgia Athens GA 30602 USA
| | - Jonathan D. Blount
- Centre for Ecology and Conservation College of Life & Environmental Sciences University of Exeter Cornwall Campus Penryn TR10 9EZ UK
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16
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S. Jones R, C. Davis S, Speed MP. Defence Cheats Can Degrade Protection of Chemically Defended Prey. Ethology 2012. [DOI: 10.1111/eth.12036] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Rebecca S. Jones
- Department of Evolution, Ecology and Behaviour; Faculty of Health & Life Sciences; Institute of Integrative Biology; University of Liverpool; Liverpool; UK
| | - Sian C. Davis
- Department of Evolution, Ecology and Behaviour; Faculty of Health & Life Sciences; Institute of Integrative Biology; University of Liverpool; Liverpool; UK
| | - Michael P. Speed
- Department of Evolution, Ecology and Behaviour; Faculty of Health & Life Sciences; Institute of Integrative Biology; University of Liverpool; Liverpool; UK
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Speed MP, Ruxton GD, Mappes J, Sherratt TN. Why are defensive toxins so variable? An evolutionary perspective. Biol Rev Camb Philos Soc 2012; 87:874-84. [PMID: 22540874 DOI: 10.1111/j.1469-185x.2012.00228.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Defensive toxins are widely used by animals, plants and micro-organisms to deter natural enemies. An important characteristic of such defences is diversity both in the quantity of toxins and the profile of specific defensive chemicals present. Here we evaluate evolutionary and ecological explanations for the persistence of toxin diversity within prey populations, drawing together a range of explanations from the literature, and adding new hypotheses. We consider toxin diversity in three ways: (1) the absence of toxicity in a proportion of individuals in an otherwise toxic prey population (automimicry); (2) broad variation in quantities of toxin within individuals in the same population; (3) variation in the chemical constituents of chemical defence. For each of these phenomena we identify alternative evolutionary explanations for the persistence of variation. One important general explanation is diversifying (frequency- or density-dependent) selection in which either costs of toxicity increase or their benefits decrease with increases in the absolute or relative abundance of toxicity in a prey population. A second major class of explanation is that variation in toxicity profiles is itself nonadaptive. One application of this explanation requires that predator behaviour is not affected by variation in levels or profiles of chemical defence within a prey population, and that there are no cost differences between different quantities or forms of toxins found within a population. Finally, the ecology and life history of the animal may enable some general predictions about toxin variation. For example, in animals which only gain their toxins in their immature forms (e.g. caterpillars on host plants) we may expect a decline in toxicity during adult life (or at least no change). By contrast, when toxins are also acquired during the adult form, we may for example expect the converse, in which young adults have less time to acquire toxicity than older adults. One major conclusion that we draw is that there are good reasons to consider within-species variation in defensive toxins as more than mere ecological noise. Rather there are a number of compelling evolutionary hypotheses which can explain and predict variation in prey toxicity.
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Affiliation(s)
- Michael P Speed
- Department of Evolution, Ecology and Behaviour, Institute of Integrative Biology, Faculty of Health & Life Sciences, University of Liverpool, UK.
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Daly D, Higginson AD, Chen D, Ruxton GD, Speed MP. Density-dependent investment in costly anti-predator defences: an explanation for the weak survival benefit of group living. Ecol Lett 2012; 15:576-83. [PMID: 22487271 DOI: 10.1111/j.1461-0248.2012.01770.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A central explanation for group living across animal taxa is the reduced rate of attack by predators. However, many field observations show a weak or non-existent effect of group size on per capita mortality rates. Herein we resolve this apparent paradox. We found that Pieris brassicae larvae defended themselves less readily when in groups than when alone, in that they were more reluctant to regurgitate in response to simulated attacks and produced less regurgitant. Furthermore, a simple model demonstrates that this reluctance was sufficient to cancel out the benefit from being in a group. This conditional strategy can be understood in terms of the costs and benefits of defences. For grouped individuals, defence is less often required because attack rates are lower and the costs of defence may be higher due to competition for resources. These phenomena are likely to be widespread in facultatively gregarious species that utilise anti-predator defences.
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Affiliation(s)
- Derek Daly
- Department of Evolution, Faculty of Health and Life Sciences, Institute of Integrative Biology, Ecology and Behaviour, Biosciences Building, University of Liverpool, Crown Street, Liverpool, UK
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Speed MP, Ruxton GD, Blount JD, Stephens PA. Diversification of honest signals in a predator-prey system. Ecol Lett 2010; 13:744-53. [PMID: 20597158 DOI: 10.1111/j.1461-0248.2010.01469.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Many animals use bright colouration to advertise their toxicity to predators. It is now well established that both toxicity and colouration are often variable within prey populations, yet it is an open question whether or not brighter signals should be used by the more toxic members of the population. We therefore describe a model in which signal honesty can easily be explained. We assumed that prey toxicity is environmentally conferred and variable between individuals, and that signalling bears a cost through attracting the attention of predators. A key assumption is that predators know the mean toxicity associated with each signalling level, so that the probability of attack for each signal value declines as mean toxicity associated with that signal increases. The probability of death given attack for each individual, however, declines with the precise value of its own toxicity, and prey must evolve the optimal level of signal to match the toxicity level that they acquire from their environments. At the start of our simulations there is no signalling system, as neither prey nor predators have biases that favour signal diversification. Over evolutionary time, however, a positive correlation emerges between signal strength and the mean toxicity associated with each signal level. When stability is reached, predators change their behaviour so that they now tend to avoid prey that signal conspicuously. In addition to predicting within-species signal reliability, our model can explain the initial evolution of aposematic displays without the need to assume special biases in predators.
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Halpin CG, Rowe C. Taste-rejection behaviour by predators can promote variability in prey defences. Biol Lett 2010; 6:617-9. [PMID: 20335201 DOI: 10.1098/rsbl.2010.0153] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The evolution and maintenance of toxicity in a prey population is a challenge to evolutionary biologists if the investment in toxin does not benefit the individual. Recent experiments suggest that taste-rejection behaviour enables predators to selectively ingest less toxic individuals, which could stabilize investment in defences. However, we currently do not know if taste rejection of defended prey is accurate across different contexts, and that prey always benefit according to their investment. Using avian predators, we show that the rejection probability does not solely depend on the investment in defence by an individual, but also on the investment by other individuals in the same population. Therefore, taste rejection by predators could lead to destabilization in the investment in defences, and allow variability in prey defences to exist.
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Affiliation(s)
- Christina G Halpin
- Centre for Behaviour and Evolution, Henry Wellcome Building, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK.
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Abstract
Internal defences such as toxins cannot be detected from a distance by a predator, and are likely to be costly to produce and maintain. Populations of well-defended prey may therefore be vulnerable to invasion from rare 'cheater' mutants that do not produce the toxin themselves but obtain some protection from their resemblance to their better defended conspecifics (automimicry). Although it is well established that well-defended and weakly defended morphs may coexist stably in protected dimorphisms, recent theoretical work suggests that such dimorphisms would not be resistant to invasion by novel mutants with defence levels intermediate to those present. Given that most defences (including toxins) are likely to be continuous traits, this implies that automimicry may tend to be a transitory phenomenon, and thus less likely to explain variation in defence levels in nature. In contrast to this, we show that automimicry can also be evolutionarily stable for continuous traits, and that it may evolve under a wide range of conditions. A recently developed geometric method allows us to determine directly from a trade-off curve whether an evolutionarily stable defence dimorphism is at all possible, and to make some qualitative inferences about the ecological conditions that may favour it.
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Affiliation(s)
- Thomas Owens Svennungsen
- Department of Biology, Centre for Ecological and Evolutionary Synthesis (CEES), University of Oslo, PO Box 1066 Blindern, 0316 Oslo, Norway.
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