1
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Bialas JT, Dylewski Ł, Tobolka M. Brain size mediates the choice of breeding strategy in the red-backed shrike Lanius collurio. Integr Zool 2024; 19:683-693. [PMID: 38196090 DOI: 10.1111/1749-4877.12803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
The brain size of vertebrates represents a trade-off between natural selection for enhanced cognitive abilities and the energetic constraints of brain tissue production. Processing information efficiently can confer benefits, but it also entails time costs. Breeding strategies, encompassing timing of breeding onset and nest-site selection, may be related to brain size. In this study, we aim to elucidate the relationship between brain size, breeding timing, nest-site choice, and breeding success in the red-backed shrike Lanius collurio. Our findings revealed that the timing of the first egg-laying date was associated with female head size, with larger-headed females tending to lay eggs later in the breeding season. Additionally, we observed that breeding success was positively correlated with increased nest concealment. However, this relationship was stronger in males with smaller heads. In turn, nest concealment was not related to head size but primarily influenced breeding onset. These results suggest that the choice of breeding strategy may be moderated by brain size, with differences between sexes. Larger-headed females may invest more time in selecting nesting sites, leading to delayed breeding onset, while larger-headed males may compensate for suboptimal nest concealment. Our study sheds light on the intricate interplay between brain size, breeding timing, nest-site preferences, and breeding success in passerine birds, underscoring the potential role of cognitive capacity in shaping individual decision-making processes.
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Affiliation(s)
- Joanna T Bialas
- Department of Zoology, Poznań University of Life Sciences, Poznań, Poland
| | - Łukasz Dylewski
- Department of Zoology, Poznań University of Life Sciences, Poznań, Poland
| | - Marcin Tobolka
- Department of Zoology, Poznań University of Life Sciences, Poznań, Poland
- Konrad Lorenz Institute of Ethology, University of Veterinary Medicine Vienna, Wien, Austria
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2
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Yang C, Cai Y. The importance of brain size for the evolution of nest complexity in birds. Integr Zool 2023; 18:1105-1107. [PMID: 37537734 DOI: 10.1111/1749-4877.12759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/05/2023]
Affiliation(s)
- Canchao Yang
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, College of Life Sciences, Hainan Normal University, Haikou, China
| | - Yan Cai
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, College of Life Sciences, Hainan Normal University, Haikou, China
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3
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De Meester G, Van Linden L, Torfs J, Pafilis P, Šunje E, Steenssens D, Zulčić T, Sassalos A, Van Damme R. Learning with lacertids: Studying the link between ecology and cognition within a comparative framework. Evolution 2022; 76:2531-2552. [PMID: 36111365 DOI: 10.1111/evo.14618] [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: 04/03/2022] [Revised: 08/10/2022] [Accepted: 08/21/2022] [Indexed: 01/22/2023]
Abstract
Cognition is an essential tool for animals to deal with environmental challenges. Nonetheless, the ecological forces driving the evolution of cognition throughout the animal kingdom remain enigmatic. Large-scale comparative studies on multiple species and cognitive traits have been advanced as the best way to facilitate our understanding of cognitive evolution, but such studies are rare. Here, we tested 13 species of lacertid lizards (Reptilia: Lacertidae) using a battery of cognitive tests measuring inhibitory control, problem-solving, and spatial and reversal learning. Next, we tested the relationship between species' performance and (a) resource availability (temperature and precipitation), habitat complexity (Normalized Difference Vegetation Index), and habitat variability (seasonality) in their natural habitat and (b) their life history (size at hatching and maturity, clutch size, and frequency). Although species differed markedly in their cognitive abilities, such variation was mostly unrelated to their ecology and life history. Yet, species living in more variable environments exhibited lower behavioral flexibility, likely due to energetic constrains in such habitats. Our standardized protocols provide opportunities for collaborative research, allowing increased sample sizes and replication, essential for moving forward in the field of comparative cognition. Follow-up studies could include more detailed measures of habitat structure and look at other potential selective drivers such as predation.
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Affiliation(s)
- Gilles De Meester
- Functional Morphology Lab, Department of Biology, University of Antwerp, Wilrijk, 2610, Belgium.,Section of Zoology and Marine Biology, Department of Biology, National and Kapodistrian University of Athens, Athens, 157 84, Greece
| | - Lisa Van Linden
- Functional Morphology Lab, Department of Biology, University of Antwerp, Wilrijk, 2610, Belgium
| | - Jonas Torfs
- Functional Morphology Lab, Department of Biology, University of Antwerp, Wilrijk, 2610, Belgium
| | - Panayiotis Pafilis
- Section of Zoology and Marine Biology, Department of Biology, National and Kapodistrian University of Athens, Athens, 157 84, Greece
| | - Emina Šunje
- Functional Morphology Lab, Department of Biology, University of Antwerp, Wilrijk, 2610, Belgium.,Department of Biology, Faculty of Natural Sciences, University of Sarajevo, Sarajevo, 71000, Bosnia and Herzegovina.,Herpetological Association in Bosnia and Herzegovina: BHHU: ATRA, Sarajevo, 71000, Bosnia and Herzegovina
| | - Dries Steenssens
- Functional Morphology Lab, Department of Biology, University of Antwerp, Wilrijk, 2610, Belgium
| | - Tea Zulčić
- Herpetological Association in Bosnia and Herzegovina: BHHU: ATRA, Sarajevo, 71000, Bosnia and Herzegovina
| | - Athanasios Sassalos
- Section of Zoology and Marine Biology, Department of Biology, National and Kapodistrian University of Athens, Athens, 157 84, Greece
| | - Raoul Van Damme
- Functional Morphology Lab, Department of Biology, University of Antwerp, Wilrijk, 2610, Belgium
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4
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Mohring B, Angelier F, Jaatinen K, Steele B, Lönnberg E, Öst M. Drivers of within- and among-individual variation in risk-taking behaviour during reproduction in a long-lived bird. Proc Biol Sci 2022; 289:20221338. [PMID: 36126681 PMCID: PMC9489283 DOI: 10.1098/rspb.2022.1338] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Accepted: 08/30/2022] [Indexed: 01/17/2023] Open
Abstract
Plastic and selective mechanisms govern parental investment adjustments to predation threat. We investigated the relative importance of plasticity and selection in risk-taking propensity of incubating female common eiders Somateria mollissima facing unprecedented predation in SW Finland, Baltic Sea. Using a 12-year individual-based dataset, we examined within- and among-individual variation in flight initiation distance (FID), in relation to predation risk, nest detectability, individual traits and reproductive investment (NFID = 1009; Nindividual = 559). We expected females nesting in riskier environments (higher predation risk, lower nest concealment) to mitigate environmentally imposed risk by exhibiting longer FIDs, and females investing more in current reproduction (older, in better condition or laying larger clutches) to display shorter FIDs. The target of predation-adult or offspring-affected the mechanisms adapting risk-taking propensity; females plastically increased their FID under higher adult predation risk, while risk-avoiding breeders were predominant on islands with higher nest predation risk. Risk-taking females selected thicker nest cover, consistent with personality-matching habitat choice. Females plastically attenuated their anti-predator response (shorter FIDs) with advancing age, and females in better body condition were more risk-taking, a result explained by selection processes. Future research should consider predator type when investigating the fitness consequences of risk-taking strategies.
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Affiliation(s)
- Bertille Mohring
- Environmental and Marine Biology, Åbo Akademi University, 20500 Turku, Finland
- Centre d'Etudes Biologiques de Chizé, UMR 7372 CNRS – La Rochelle Université, 79360 Villiers-en-Bois, France
| | - Frédéric Angelier
- Centre d'Etudes Biologiques de Chizé, UMR 7372 CNRS – La Rochelle Université, 79360 Villiers-en-Bois, France
| | - Kim Jaatinen
- Nature and Game Management Trust Finland, 10160 Degerby, Finland
| | - Ben Steele
- School of Arts and Sciences, Colby-Sawyer College, New London, NH 03257, USA
| | | | - Markus Öst
- Environmental and Marine Biology, Åbo Akademi University, 20500 Turku, Finland
- Novia University of Applied Sciences, 10600 Ekenäs, Finland
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Gavriilidi I, De Meester G, Van Damme R, Baeckens S. How to behave when marooned: the behavioural component of the island syndrome remains underexplored. Biol Lett 2022; 18:20220030. [PMID: 35440235 PMCID: PMC9039784 DOI: 10.1098/rsbl.2022.0030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 03/25/2022] [Indexed: 12/16/2022] Open
Abstract
Animals on islands typically depart from their mainland relatives in assorted aspects of their biology. Because they seem to occur in concert, and to some extent evolve convergently in disparate taxa, these changes are referred to as the 'island syndrome'. While morphological, physiological and life-history components of the island syndrome have received considerable attention, much less is known about how insularity affects behaviour. In this paper, we argue why changes in personality traits and cognitive abilities can be expected to form part of the island syndrome. We provide an overview of studies that have compared personality traits and cognitive abilities between island and mainland populations, or among islands. Overall, the pickings are remarkably slim. There is evidence that animals on islands tend to be bolder than on the mainland, but effects on other personality traits go either way. The evidence for effects of insularity on cognitive abilities or style is highly circumstantial and very mixed. Finally, we consider the ecological drivers that may induce such changes, and the mechanisms through which they might occur. We conclude that our knowledge of the behavioural and cognitive responses to island environments remains limited, and we encourage behavioural biologists to make more use of these 'natural laboratories for evolution'.
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Affiliation(s)
- Ioanna Gavriilidi
- Functional Morphology Lab, Department of Biology, University of Antwerp, Wilrijk, Belgium
- Section of Zoology and Marine Biology, Department of Biology, National and Kapodistrian University of Athens, Greece
| | - Gilles De Meester
- Functional Morphology Lab, Department of Biology, University of Antwerp, Wilrijk, Belgium
| | - Raoul Van Damme
- Functional Morphology Lab, Department of Biology, University of Antwerp, Wilrijk, Belgium
| | - Simon Baeckens
- Functional Morphology Lab, Department of Biology, University of Antwerp, Wilrijk, Belgium
- Evolution and Optics of Nanostructures Lab, Department of Biology, Ghent University, Ghent, Belgium
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6
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OUP accepted manuscript. Behav Ecol 2022. [DOI: 10.1093/beheco/arac031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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7
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Møller AP, Laursen K, Izaguirre J, Marzal A. Antibacterial and anatomical defenses in an oil contaminated, vulnerable seaduck. Ecol Evol 2021; 11:12520-12528. [PMID: 34594517 PMCID: PMC8462148 DOI: 10.1002/ece3.7996] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 07/04/2021] [Accepted: 07/06/2021] [Indexed: 01/29/2023] Open
Abstract
Oil spills have killed thousands of birds during the last 100 years, but nonlethal effects of oil spills on birds remain poorly studied. We measured phenotype characters in 819 eiders Somateria mollissima (279 whole birds and 540 wings) of which 13.6% were oiled. We tested the hypotheses that (a) the morphology of eiders does not change due to oil contamination; (b) the anatomy of organs reflects the physiological reaction to contamination, for example, increase in metabolic demand, increase in food intake, and counteracting toxic effects of oil; (c) large locomotion apparatus that facilitates locomotion increases the risk of getting oiled; and (d) individual eiders with a higher production of secretions from the uropygial grand were more likely to have oil on their plumage. We tested whether 19 characters differed between oiled and nonoiled individuals, showing a consistent pattern. The final model retained seven predictor variables showing relationships between eiders contaminated with oil and food consumption, flight, and diving abilities. We tested whether these effects were due to differences in body condition, liver mass, empty gizzard mass, or other characters that could have been affected by impaired flight and diving ability. There was no evidence of such negative impact of oiling on eiders. We found that significant exposure to oil was associated with increased diversity of antibacterial defense. Oiled eiders did not constitute a random sample, and superior diving ability as reflected by large foot area was at a selective disadvantage during oil spills. Thus, specific characteristics predispose eiders to oiling, with an adaptation to swimming, diving, and flying being traded against the costs of oiling. In contrast, individuals with a high degree of physiological plasticity may experience an advantage because their uropygial secretions counteract the effects of oil contamination.
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Affiliation(s)
- Anders Pape Møller
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological EngineeringCollege of Life SciencesBeijing Normal UniversityBeijingChina
- Ecologie Systématique EvolutionCNRSUniversité Paris‐SaclayOrsay CedexFrance
| | | | | | - Alfonso Marzal
- Department of ZoologyUniversity of ExtremaduraBadajozSpain
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Todorov OS, Blomberg SP, Goswami A, Sears K, Drhlík P, Peters J, Weisbecker V. Testing hypotheses of marsupial brain size variation using phylogenetic multiple imputations and a Bayesian comparative framework. Proc Biol Sci 2021; 288:20210394. [PMID: 33784860 PMCID: PMC8059968 DOI: 10.1098/rspb.2021.0394] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 03/01/2021] [Indexed: 12/20/2022] Open
Abstract
Considerable controversy exists about which hypotheses and variables best explain mammalian brain size variation. We use a new, high-coverage dataset of marsupial brain and body sizes, and the first phylogenetically imputed full datasets of 16 predictor variables, to model the prevalent hypotheses explaining brain size evolution using phylogenetically corrected Bayesian generalized linear mixed-effects modelling. Despite this comprehensive analysis, litter size emerges as the only significant predictor. Marsupials differ from the more frequently studied placentals in displaying a much lower diversity of reproductive traits, which are known to interact extensively with many behavioural and ecological predictors of brain size. Our results therefore suggest that studies of relative brain size evolution in placental mammals may require targeted co-analysis or adjustment of reproductive parameters like litter size, weaning age or gestation length. This supports suggestions that significant associations between behavioural or ecological variables with relative brain size may be due to a confounding influence of the extensive reproductive diversity of placental mammals.
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Affiliation(s)
- Orlin S. Todorov
- School of Biological Sciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Simone P. Blomberg
- School of Biological Sciences, The University of Queensland, St Lucia, Queensland, Australia
| | - Anjali Goswami
- Genetics, Evolution, and Environment Department, University College London, UK
- Department of Life Sciences, Natural History Museum, London, UK
| | - Karen Sears
- Department of Ecology and Evolutionary Biology, College of Life Sciences, University of California Los Angeles, CA, USA
| | - Patrik Drhlík
- Faculty of Mechatronics, Informatics and Interdisciplinary Studies, Technical University of Liberec, Czechia
| | - James Peters
- Department of Animal Biology, University of Illinois at Urbana Champaign, USA
| | - Vera Weisbecker
- School of Biological Sciences, The University of Queensland, St Lucia, Queensland, Australia
- College of Science and Engineering, Flinders University, Australia
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9
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Laursen K, Møller AP. Brain mass explains prey size selection better than beak, gizzard and body size in a benthivorous duck species. PLoS One 2021; 16:e0248615. [PMID: 33784342 PMCID: PMC8009388 DOI: 10.1371/journal.pone.0248615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 03/02/2021] [Indexed: 11/19/2022] Open
Abstract
Prey size selection in some bird species is determined by the size of the beak. However, we assumed for bird species swallowing whole prey that a cognitive process may be involved. As cognitive feature, brain mass was used. We hypothesized that the mass of the brain was more strongly positively correlated with prey size than morphological features such as beak volume, gizzard mass and body mass. We tested this hypothesis on eiders Somateria mollissima that swallow the prey whole, by using mean and maximum size of nine prey categories. Eiders were collected at the main wintering grounds in Denmark. As index of brain mass we used head volume, which is positively correlated with brain mass (r2 = 0.73). Head volume of eiders was significantly, positive correlated with mean and maximum size of blue mussels Mytilus edulis, razor clams Ensis directus and all prey sizes combined and the maximum size of draft whelk Hinia reticulata and conch Buccinum undatum. Gizzard mass was also significantly positively correlated with maximum size of draft whelk and conch. Beak volume and body mass was not significantly correlated with the size of any of the nine food items. Analyses of effect size for organs showed that head volume was positively related to prey size, whereas beak volume, gizzard mass and body mass did not show a significant positive relationship. These results indicate that cognitive processes connected to brain mass may be involved in prey size selection by eiders.
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Affiliation(s)
- Karsten Laursen
- Department of Bioscience, Aarhus University, Rønde, Denmark
- * E-mail:
| | - Anders Pape Møller
- Ecologie Systématique Evolution, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, Orsay Cedex, France
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10
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Møller AP, Hongisto K, Korpimäki E. Predation risk in relation to brain size in alternative prey of pygmy owls varies depending on the abundance of main prey. PLoS One 2020; 15:e0236155. [PMID: 32915780 PMCID: PMC7485837 DOI: 10.1371/journal.pone.0236155] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 06/30/2020] [Indexed: 11/23/2022] Open
Abstract
Large brains in prey may select for adoption of anti-predator behavior that facilitates escape. Prey species with relatively large brains have been shown to be less likely to fall prey to predators. This results in the prediction that individuals that have been captured by predators on average should have smaller brains than sympatric conspecifics. We exploited the fact that Eurasian pygmy owls Glaucidium passerinum hoard small mammals and birds in cavities and nest-boxes for over-winter survival, allowing for comparison of the phenotype of prey with that of live conspecifics. In Northern Europe, main prey of pygmy owls are voles of the genera Myodes and Microtus, while forest birds and shrews are the most important alternative prey. Large fluctuations (amplitude 100-200-fold) in vole populations induce rapid numerical responses of pygmy owls to main prey populations, which in turn results in varying predation pressure on small birds. We found, weighed and measured 153 birds in food-stores of pygmy owls and mist-netted, weighed and measured 333 live birds of 12 species in central-western Finland during two autumns with low (2017) and high (2018) pygmy owl predation risk. In two autumns, individuals with large brains were captured later compared to individuals with small brains, consistent with the hypothesis that such individuals survived for longer. Avian prey of pygmy owls had smaller heads than live birds in autumn 2018 when predation risk by pygmy owls was high. This difference in head size was not significant in 2017 when predation risk by pygmy owls was reduced. Finally, avian survivors were in better body condition than avian prey individuals. These findings are consistent with the hypothesis that pygmy owls differentially prey on birds in poor condition with small brains. These findings are consistent with the hypothesis that predation risk imposed by pygmy owls on small birds in boreal forests varies depending on the abundance of the main prey (voles).
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Affiliation(s)
- Anders Pape Møller
- Ecologie Systématique Evolution, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, France
- * E-mail:
| | | | - Erkki Korpimäki
- Section of Ecology, Department of Biology, University of Turku, Turku, Finland
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Liu J, Yang C, Yu J, Wang H, Møller AP, Liang W. Egg recognition and brain size in a cuckoo host. Behav Processes 2020; 180:104223. [PMID: 32841719 DOI: 10.1016/j.beproc.2020.104223] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 08/14/2020] [Accepted: 08/18/2020] [Indexed: 11/28/2022]
Abstract
The evolution of animal brain size and cognitive ability is a topic of central significance in evolutionary ecology. Interspecific brood parasitism imposes severe selection pressures on hosts favoring the evolution of cuckoo egg recognition and rejection. However, recognizing and rejecting foreign parasitic eggs are enormous cognitive challenges for cuckoo hosts, which might select for an increase in brain size in birds with this capacity. To explore the association between cuckoo parasitism and the evolution of brain size in cinereous tits (Parus cinereus), we used two types of experimental parasitic eggs, real mimetic white-rumped munia (Lonchura striata) eggs and non-mimetic blue model eggs, to test the egg recognition ability of female cinereous tits, thereby comparing brain size variation among individuals that were able to recognize foreign eggs and those that lacked this ability. Interestingly, our results however did not support the prediction that cuckoo parasitism selects for an increase in brain size of host birds, since brain size of egg rejecters was not significantly larger than that of accepters. Hence, this study suggested that the evolution of cognitive ability did not allow recognition of foreign eggs by female cinereous tits. That was the case despite the evolution of a larger brain may have allowed for a reduction in the cost of brood parasitism by cuckoos.
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Affiliation(s)
- Jianping Liu
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, College of Life Sciences, Hainan Normal University, Haikou, 571158, China.
| | - Canchao Yang
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, College of Life Sciences, Hainan Normal University, Haikou, 571158, China.
| | - Jiangping Yu
- Jilin Engineering Laboratory for Avian Ecology and Conservation Genetics, School of Life Sciences, Northeast Normal University, Changchun, 130024, China; Ministry of Education Key Laboratory of Vegetation Ecology, School of Life Sciences, Northeast Normal University, Changchun, 130024, China.
| | - Haitao Wang
- Jilin Engineering Laboratory for Avian Ecology and Conservation Genetics, School of Life Sciences, Northeast Normal University, Changchun, 130024, China; Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization, School of Life Sciences, Northeast Normal University, Changchun, 130024, China.
| | - Anders Pape Møller
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, 100875, China; Ecologie Systématique Evolution, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, F-91405, Orsay Cedex, France.
| | - Wei Liang
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, College of Life Sciences, Hainan Normal University, Haikou, 571158, China.
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Mesocarnivores affect hispid cotton rat (Sigmodon hispidus) body mass. Sci Rep 2019; 9:14615. [PMID: 31602009 PMCID: PMC6787243 DOI: 10.1038/s41598-019-51168-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 09/25/2019] [Indexed: 11/24/2022] Open
Abstract
Predator communities are changing worldwide: large carnivores are declining while mesocarnivores (medium-sized mammalian predators) are increasing in number and ecological influence. Predator choice of prey is not random and different predators select prey with different characteristics. Changes in predator communities can change predation patterns experienced by prey. Little is known about how mesocarnivore communities influence prey morphology. We used 14 years of mark-recapture data to investigate how mesocarnivore exclusion affected body mass of hispid cotton rats (Sigmodon hispidus). Finding adult male cotton rats were 9% heavier with mesocarnivore exclusion, we developed hypotheses to explain this observation. Greater adult male body mass in exclosures resulted from: (1) a non-significant trend of increased survival of large males, (2) faster juvenile male growth during the fall and a similar non-significant trend among adult males, and (3) spatial partitioning by size among males. Taxa-specific predation rates (i.e., rates of predation by snakes, raptors, or mesocarnivores) did not differ among male body mass classes. Mesocarnivores disproportionately preyed on large females while raptors targeted small females, but female body mass was not influenced by mesocarnivore exclusion. Changes in predator communities can result in multiple small effects that collectively result in large differences in prey morphology.
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