Pub Date : 2024-03-05DOI: 10.1093/biolinnean/blae006
Gita R Kolluru, Yasmine J Akky, Alana Weissman, Hilary Poore, Dana Weiner, Ryan L Earley
Behaviours can be adaptively correlated with each other and with other aspects of phenotype. We investigated behaviour across foraging, mating, and risk contexts in females of the poeciliid fish, Girardinus metallicus. We quantified relationships between these behaviours and aggression signals, body size, and reproductive output. Behaviours describing aggression and boldness, some of which were repeatable, were correlated in females. Aggression was signalled by the darkening of a black spot on the extended dorsal fin or by fin flaring. Spot darkening occurred during intra- and intersexual interactions and was positively correlated with interfemale aggression and negatively correlated with the time females spent following males, suggesting that it is an honest indicator of motivational state. In contrast, fin flaring was directed only at females and occurred more frequently in the foraging context. Larger females had fewer offspring and received fewer courtship displays, possibly because they were more aggressive to males. In contrast to studies of males, we found a negative relationship between rank order of boldness and aggression, consistent with either a trade-off or with selection favouring the negative relationship. Our results highlight the importance of studying females in model systems to uncover novel patterns and potentially meaningful departures from what is typically seen in males.
{"title":"Cross-context behavioural correlations and signals of aggression in females of a livebearing fish","authors":"Gita R Kolluru, Yasmine J Akky, Alana Weissman, Hilary Poore, Dana Weiner, Ryan L Earley","doi":"10.1093/biolinnean/blae006","DOIUrl":"https://doi.org/10.1093/biolinnean/blae006","url":null,"abstract":"Behaviours can be adaptively correlated with each other and with other aspects of phenotype. We investigated behaviour across foraging, mating, and risk contexts in females of the poeciliid fish, Girardinus metallicus. We quantified relationships between these behaviours and aggression signals, body size, and reproductive output. Behaviours describing aggression and boldness, some of which were repeatable, were correlated in females. Aggression was signalled by the darkening of a black spot on the extended dorsal fin or by fin flaring. Spot darkening occurred during intra- and intersexual interactions and was positively correlated with interfemale aggression and negatively correlated with the time females spent following males, suggesting that it is an honest indicator of motivational state. In contrast, fin flaring was directed only at females and occurred more frequently in the foraging context. Larger females had fewer offspring and received fewer courtship displays, possibly because they were more aggressive to males. In contrast to studies of males, we found a negative relationship between rank order of boldness and aggression, consistent with either a trade-off or with selection favouring the negative relationship. Our results highlight the importance of studying females in model systems to uncover novel patterns and potentially meaningful departures from what is typically seen in males.","PeriodicalId":55373,"journal":{"name":"Biological Journal of the Linnean Society","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140045475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-05DOI: 10.1093/biolinnean/blae026
Alessandra Bartimachi, Thais B Pimenta, Francismeire J Telles, Ernane H M Vieira-Neto, João C F Cardoso, Heraldo L Vasconcelos, Alan N Costa
Co-evolving organisms experience multiple selection pressures that may lead to trait mismatches among different populations and sites. In defensive ant–plant mutualisms, host plants (myrmecophytes) produce specialized shelters (domatia) to harbour specialized ant-partners in exchange for protection against enemies. Although populations of myrmecophytes without ants occur in some locations, there are no records of changes in domatia morphology—at the population level—due to the absence of symbiotic ants. We conducted broad-scale samplings of Miconia tococa (Melastomataceae) populations across the Brazilian Cerrado and a 2-year transplant experiment to test whether domatia morphology changes when symbiotic ants are naturally absent. Domatia were 33.9% smaller in ant-free populations than in ant-inhabited populations. Transplants revealed that host plants from ant-inhabited sites still developed larger domatia than those from ant-free sites, even in the absence of ant-partners. These findings point to a change of M. tococa traits associated with biotic defences where symbiotic ants are absent. What may have begun as a plastic adjustment to ant-free environments appears to have been transformed into fixed (genetic) interpopulation differences over time, indicating a potential local destabilization of the mutualism or a mechanism to stabilize the interaction at the landscape scale.
{"title":"Morphological divergence of domatia in ant-free populations of the widespread Neotropical myrmecophyte Miconia tococa (Melastomataceae)","authors":"Alessandra Bartimachi, Thais B Pimenta, Francismeire J Telles, Ernane H M Vieira-Neto, João C F Cardoso, Heraldo L Vasconcelos, Alan N Costa","doi":"10.1093/biolinnean/blae026","DOIUrl":"https://doi.org/10.1093/biolinnean/blae026","url":null,"abstract":"Co-evolving organisms experience multiple selection pressures that may lead to trait mismatches among different populations and sites. In defensive ant–plant mutualisms, host plants (myrmecophytes) produce specialized shelters (domatia) to harbour specialized ant-partners in exchange for protection against enemies. Although populations of myrmecophytes without ants occur in some locations, there are no records of changes in domatia morphology—at the population level—due to the absence of symbiotic ants. We conducted broad-scale samplings of Miconia tococa (Melastomataceae) populations across the Brazilian Cerrado and a 2-year transplant experiment to test whether domatia morphology changes when symbiotic ants are naturally absent. Domatia were 33.9% smaller in ant-free populations than in ant-inhabited populations. Transplants revealed that host plants from ant-inhabited sites still developed larger domatia than those from ant-free sites, even in the absence of ant-partners. These findings point to a change of M. tococa traits associated with biotic defences where symbiotic ants are absent. What may have begun as a plastic adjustment to ant-free environments appears to have been transformed into fixed (genetic) interpopulation differences over time, indicating a potential local destabilization of the mutualism or a mechanism to stabilize the interaction at the landscape scale.","PeriodicalId":55373,"journal":{"name":"Biological Journal of the Linnean Society","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140045675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-02DOI: 10.1093/biolinnean/blae023
Clint D Kelly, Valerie L’Heureux
The density-dependent prophylaxis hypothesis posits that because pathogens are expected to be transmitted among conspecifics in crowded conditions, individuals living in such conditions should minimize their chance of infection and maximize survival by elevating their baseline immunity. Further, if individuals developing in crowded conditions indeed allocate more resources to immunity then resource allocation to other life-history traits, such as reproduction, should decline. We tested these hypotheses by rearing sand crickets (Gryllus firmus) at either low or high density in the laboratory and quantified immune function (melanotic encapsulation response) and reproductive investment (ovary mass, egg size) at adulthood. The results did not support the density-dependent prophylaxis hypothesis, but we did find that rearing density significantly affected investment in two reproductive traits, with average ovary mass and egg size both being larger in low-density crickets. We discuss possible explanations for the lack of a trade-off between immunity and reproduction in our study.
{"title":"Effect of rearing density on female investment in reproduction and melanotic encapsulation response in the sand cricket (Gryllus firmus) (Orthoptera: Gryllidae)","authors":"Clint D Kelly, Valerie L’Heureux","doi":"10.1093/biolinnean/blae023","DOIUrl":"https://doi.org/10.1093/biolinnean/blae023","url":null,"abstract":"The density-dependent prophylaxis hypothesis posits that because pathogens are expected to be transmitted among conspecifics in crowded conditions, individuals living in such conditions should minimize their chance of infection and maximize survival by elevating their baseline immunity. Further, if individuals developing in crowded conditions indeed allocate more resources to immunity then resource allocation to other life-history traits, such as reproduction, should decline. We tested these hypotheses by rearing sand crickets (Gryllus firmus) at either low or high density in the laboratory and quantified immune function (melanotic encapsulation response) and reproductive investment (ovary mass, egg size) at adulthood. The results did not support the density-dependent prophylaxis hypothesis, but we did find that rearing density significantly affected investment in two reproductive traits, with average ovary mass and egg size both being larger in low-density crickets. We discuss possible explanations for the lack of a trade-off between immunity and reproduction in our study.","PeriodicalId":55373,"journal":{"name":"Biological Journal of the Linnean Society","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140020002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-02DOI: 10.1093/biolinnean/blae024
L Grey, G I Holwell, J M Jandt, S Johnson
Many animals develop and use exaggerated weapons in contests over access to mating opportunities. Stag beetles (family Lucanidae) show striking sexual dimorphism, where the males have heavily exaggerated mandibles that the females do not possess. In some genera, size and shape can also vary drastically between small and large males resulting in discrete alternative male morphs, described as male dimorphism. The genus Geodorcus is a poorly studied and threatened group of stag beetles that are endemic to New Zealand. Geodorcus helmsi is the most widespread species in this genus and presents an opportunity to test for the presence of both sexual and male dimorphism and investigate the scaling relationships (allometry) of mandibles in this group. We used linear and geometric morphometric analyses on wild populations and museum specimens from Stewart Island, New Zealand, to assess whether G. helmsi exhibits male dimorphism. We found that within a single population, there is no evidence for alternative male morphs, but a gradual shift between smaller and larger individuals. We also found that male mandibles exhibit steep positive allometry in contrast to the negative allometry found in the mandibles of females, as is often found for sexually selected weaponry. Moreover, we found evidence that left and right mandibles of G. helmsi are subtly asymmetric. Our results provide context for the competitive behaviour observed in this species, and give insights into potential trade-offs between smaller and larger individuals of the Helm’s stag beetle.
{"title":"Weapon allometry and shape variation in the Helm’s stag beetle (Geodorcus helmsi)","authors":"L Grey, G I Holwell, J M Jandt, S Johnson","doi":"10.1093/biolinnean/blae024","DOIUrl":"https://doi.org/10.1093/biolinnean/blae024","url":null,"abstract":"Many animals develop and use exaggerated weapons in contests over access to mating opportunities. Stag beetles (family Lucanidae) show striking sexual dimorphism, where the males have heavily exaggerated mandibles that the females do not possess. In some genera, size and shape can also vary drastically between small and large males resulting in discrete alternative male morphs, described as male dimorphism. The genus Geodorcus is a poorly studied and threatened group of stag beetles that are endemic to New Zealand. Geodorcus helmsi is the most widespread species in this genus and presents an opportunity to test for the presence of both sexual and male dimorphism and investigate the scaling relationships (allometry) of mandibles in this group. We used linear and geometric morphometric analyses on wild populations and museum specimens from Stewart Island, New Zealand, to assess whether G. helmsi exhibits male dimorphism. We found that within a single population, there is no evidence for alternative male morphs, but a gradual shift between smaller and larger individuals. We also found that male mandibles exhibit steep positive allometry in contrast to the negative allometry found in the mandibles of females, as is often found for sexually selected weaponry. Moreover, we found evidence that left and right mandibles of G. helmsi are subtly asymmetric. Our results provide context for the competitive behaviour observed in this species, and give insights into potential trade-offs between smaller and larger individuals of the Helm’s stag beetle.","PeriodicalId":55373,"journal":{"name":"Biological Journal of the Linnean Society","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140020004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Himalayan vulture (Gyps himalayensis) has higher environmental specificity than other species in the same genus, and its population has declined due to diclofenac exposure and shortage of carcasses as a food source. Previous analysis of mitochondrial (mt) DNA cytochrome b (Cyt b) sequences reported no distinct geographical population structure in the Himalayan vulture. Contradictory results were obtained in the present study, which investigated the population structure of 14 Himalayan vultures that migrated to Thailand during winter. Using samples obtained between 2010 and 2021, as well as limited GenBank samples, the study found that the Cyt b locus was incapable of distinguishing population structure. This dataset contrasted with the mtDNA control region (CR) and Cyt b + CR dataset, which divided them into two groups, as explained by the Middle–Late Pleistocene climate change scenario. The species split into populations from the central, western, and northern regions of its distribution range within the highland vulture ecological niche. This study reviews the different methods used as compared with previous proposals for defining guidelines for the conservation of this near-threatened scavenging species.
喜马拉雅鹫（Gyps himalayensis）比同属的其他物种具有更高的环境特异性，其种群数量因接触双氯芬酸和缺少作为食物来源的尸体而减少。之前的线粒体 DNA 细胞色素 b（Cyt b）序列分析报告称，喜马拉雅鹫没有明显的地理种群结构。本研究调查了 14 只冬季迁徙到泰国的喜马拉雅秃鹫的种群结构，结果却截然相反。利用 2010 年至 2021 年间获得的样本以及有限的 GenBank 样本，研究发现 Cyt b 基因座无法区分种群结构。该数据集与 mtDNA 控制区（CR）和 Cyt b + CR 数据集形成了鲜明对比，后者根据中晚更新世气候变化情景将其分为两组。在高原秃鹫生态位内，该物种分为来自其分布区中部、西部和北部的种群。本研究回顾了所使用的不同方法，并与之前的建议进行了比较，以确定保护这一濒临灭绝的食腐物种的指导方针。
{"title":"Deep mitochondrial phylogeographical pattern: cryptic population structure within an ecological niche in the near-threatened Himalayan vulture (Gyps himalayensis)","authors":"Chanatip Ummee, Ratiwan Sitdhibutr, Preeda Lertwatcharasarakul, Chaiyan Kasorndorkbua","doi":"10.1093/biolinnean/blae021","DOIUrl":"https://doi.org/10.1093/biolinnean/blae021","url":null,"abstract":"The Himalayan vulture (Gyps himalayensis) has higher environmental specificity than other species in the same genus, and its population has declined due to diclofenac exposure and shortage of carcasses as a food source. Previous analysis of mitochondrial (mt) DNA cytochrome b (Cyt b) sequences reported no distinct geographical population structure in the Himalayan vulture. Contradictory results were obtained in the present study, which investigated the population structure of 14 Himalayan vultures that migrated to Thailand during winter. Using samples obtained between 2010 and 2021, as well as limited GenBank samples, the study found that the Cyt b locus was incapable of distinguishing population structure. This dataset contrasted with the mtDNA control region (CR) and Cyt b + CR dataset, which divided them into two groups, as explained by the Middle–Late Pleistocene climate change scenario. The species split into populations from the central, western, and northern regions of its distribution range within the highland vulture ecological niche. This study reviews the different methods used as compared with previous proposals for defining guidelines for the conservation of this near-threatened scavenging species.","PeriodicalId":55373,"journal":{"name":"Biological Journal of the Linnean Society","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140005645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Scleractinian corals play important roles in the maintenance and restoration of coral systems. However, the evolutionary relationships among species remain unclear, mostly due to the limitations of traditional coral classifications because of their ecophenotypic variation and morphological plasticity. Thus, here we aimed to reconstruct the phylogenetic relationships of corals through single- and multi-gene analyses based on 116 colonies (14 families and 49 species) from Weizhou Island, China, and five molecular markers (CO1, 16S rRNA, 12S rRNA, H3, and ITS). The results reveal four cryptic species (Platygyra pini, Platygyra verweyi, Psammocora nierstraszi, and Coscinaraea columna). In single-gene analyses, mitochondrial genes can classify taxa at the family but not genus level, and vice versa for nuclear genes. Species are divided into complex and robust corals based on multi-gene analysis. Within robust corals, Merulinidae (Group XVII) is classified into eight subclades, and Dipsastraea, Favites, and Goniastrea are polyphyletic. Complex corals comprise the monophyletic Acroporidae (VI), Agariciidae (VII), Euphylliidae (V), Porites (III), and Dendrophylliidae (II). Notably, Turbinaria peltata is highly divergent from its congeners and clusters. Multi-gene analysis proved to be more accurate than single-gene analysis in elucidating phylogenetic relationships among corals. This study enhances our understanding of the diversity, evolution, and conservation of corals from Weizhou Island.
{"title":"Molecular phylogenetic classification of scleractinian corals from Weizhou Island, China","authors":"Xinru Zeng, Fen Wei, Mengyao Cui, Haoyu Yu, Xiaoyuan Pan, Zhiming Ning, Kefu Yu","doi":"10.1093/biolinnean/blae022","DOIUrl":"https://doi.org/10.1093/biolinnean/blae022","url":null,"abstract":"Scleractinian corals play important roles in the maintenance and restoration of coral systems. However, the evolutionary relationships among species remain unclear, mostly due to the limitations of traditional coral classifications because of their ecophenotypic variation and morphological plasticity. Thus, here we aimed to reconstruct the phylogenetic relationships of corals through single- and multi-gene analyses based on 116 colonies (14 families and 49 species) from Weizhou Island, China, and five molecular markers (CO1, 16S rRNA, 12S rRNA, H3, and ITS). The results reveal four cryptic species (Platygyra pini, Platygyra verweyi, Psammocora nierstraszi, and Coscinaraea columna). In single-gene analyses, mitochondrial genes can classify taxa at the family but not genus level, and vice versa for nuclear genes. Species are divided into complex and robust corals based on multi-gene analysis. Within robust corals, Merulinidae (Group XVII) is classified into eight subclades, and Dipsastraea, Favites, and Goniastrea are polyphyletic. Complex corals comprise the monophyletic Acroporidae (VI), Agariciidae (VII), Euphylliidae (V), Porites (III), and Dendrophylliidae (II). Notably, Turbinaria peltata is highly divergent from its congeners and clusters. Multi-gene analysis proved to be more accurate than single-gene analysis in elucidating phylogenetic relationships among corals. This study enhances our understanding of the diversity, evolution, and conservation of corals from Weizhou Island.","PeriodicalId":55373,"journal":{"name":"Biological Journal of the Linnean Society","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140005512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-25DOI: 10.1093/biolinnean/blae017
Shin-ya Ohba, Tomoya Suzuki, Mizuki Fukui, Sachiko Hirai, Karin Nakashima, Yeon Jae Bae, Koji Tojo
Diving beetles play an important role in fishless freshwater communities. The genus Cybister is included in the Japanese Red Data List owing to its diminished population size. The phylogenetic relationships and genetic structures of Cybister chinensis and Cybister brevis, whose populations are declining, and Cybister tripunctatus lateralis, whose population and distribution is increasing, are poorly understood and must be addressed in future conservation efforts. In this study, we investigated the flight behaviour and phylogeography of the three Cybister species. Cybistyer tripunctatus lateralis and C. brevis flew well in the spring, and the proportion of flight in C. tripunctatus lateralis increased again after the reproductive season. However, C. chinensis did not fly. Relatively, among the three species, C. tripunctatus lateralis has the largest forewings. Phylogenetic analysis based on mitochondrial DNA revealed that C. chinensis showed genetic differentiation between the eastern and western regions of Japan, whereas C. tripunctatus lateralis showed no regional trends. Furthermore, C. brevis showed an intermediate trend between the two species. These findings suggest that C. tripunctatus lateralis has been expanding the area of its distribution rapidly through flight dispersal in recent years. Cybister chinensis flies infrequently, raising concerns about metapopulation fragmentation.
{"title":"Flight characteristics and phylogeography in three large-bodied diving beetle species: evidence that the species with expanded distribution is an active flier","authors":"Shin-ya Ohba, Tomoya Suzuki, Mizuki Fukui, Sachiko Hirai, Karin Nakashima, Yeon Jae Bae, Koji Tojo","doi":"10.1093/biolinnean/blae017","DOIUrl":"https://doi.org/10.1093/biolinnean/blae017","url":null,"abstract":"Diving beetles play an important role in fishless freshwater communities. The genus Cybister is included in the Japanese Red Data List owing to its diminished population size. The phylogenetic relationships and genetic structures of Cybister chinensis and Cybister brevis, whose populations are declining, and Cybister tripunctatus lateralis, whose population and distribution is increasing, are poorly understood and must be addressed in future conservation efforts. In this study, we investigated the flight behaviour and phylogeography of the three Cybister species. Cybistyer tripunctatus lateralis and C. brevis flew well in the spring, and the proportion of flight in C. tripunctatus lateralis increased again after the reproductive season. However, C. chinensis did not fly. Relatively, among the three species, C. tripunctatus lateralis has the largest forewings. Phylogenetic analysis based on mitochondrial DNA revealed that C. chinensis showed genetic differentiation between the eastern and western regions of Japan, whereas C. tripunctatus lateralis showed no regional trends. Furthermore, C. brevis showed an intermediate trend between the two species. These findings suggest that C. tripunctatus lateralis has been expanding the area of its distribution rapidly through flight dispersal in recent years. Cybister chinensis flies infrequently, raising concerns about metapopulation fragmentation.","PeriodicalId":55373,"journal":{"name":"Biological Journal of the Linnean Society","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139951686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-24DOI: 10.1093/biolinnean/blae020
Marina Meireles dos Santos, Julia Klaczko, Ana Lúcia da Costa Prudente
Sexual dimorphism is a common phenomenon among snakes, with female snakes being larger than male snakes as a recurrent pattern . However, species that show male-male combat behaviour may impose a selective advantage by developing larger bodies in male specimens, like the diurnal Chironius snakes, which display courtship and male-male combat behaviours. In this study, we analysed sexual dimorphism in body, tail, and head size, and skull size and shape in twelve species of Chironius. We investigated whether sexual dimorphism patterns could be a result of allometric growth. The absence of sexual dimorphism regarding body and head length was the main pattern revealed by our analyses. Sexual dimorphism characterized by larger body and head sizes in males was observed in Chironius bicarinatus, Chironius foveatus, and Chironius fuscus. Only females of Chironius exoletus exhibited larger body and head sizes than males. Regarding the shape of the head, six species showed sexual divergences, with enlarged or robust heads. Sexual dimorphism in skull shape seems related to selection in Chironius flavolineatus, with no allometric influences. Larger tails in males of C. fuscus, C. flavolineatus, and Chironius quadricarinatus may represent an advantageous defensive strategy. Finally, the lack of divergence in tail length in the remaining species probably evolved due to arboreal habits in Chironius.
{"title":"Sexual dimorphism in the Neotropical snakes genus Chironius (Serpentes: Colubridae)","authors":"Marina Meireles dos Santos, Julia Klaczko, Ana Lúcia da Costa Prudente","doi":"10.1093/biolinnean/blae020","DOIUrl":"https://doi.org/10.1093/biolinnean/blae020","url":null,"abstract":"Sexual dimorphism is a common phenomenon among snakes, with female snakes being larger than male snakes as a recurrent pattern . However, species that show male-male combat behaviour may impose a selective advantage by developing larger bodies in male specimens, like the diurnal Chironius snakes, which display courtship and male-male combat behaviours. In this study, we analysed sexual dimorphism in body, tail, and head size, and skull size and shape in twelve species of Chironius. We investigated whether sexual dimorphism patterns could be a result of allometric growth. The absence of sexual dimorphism regarding body and head length was the main pattern revealed by our analyses. Sexual dimorphism characterized by larger body and head sizes in males was observed in Chironius bicarinatus, Chironius foveatus, and Chironius fuscus. Only females of Chironius exoletus exhibited larger body and head sizes than males. Regarding the shape of the head, six species showed sexual divergences, with enlarged or robust heads. Sexual dimorphism in skull shape seems related to selection in Chironius flavolineatus, with no allometric influences. Larger tails in males of C. fuscus, C. flavolineatus, and Chironius quadricarinatus may represent an advantageous defensive strategy. Finally, the lack of divergence in tail length in the remaining species probably evolved due to arboreal habits in Chironius.","PeriodicalId":55373,"journal":{"name":"Biological Journal of the Linnean Society","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139951736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-24DOI: 10.1093/biolinnean/blad167
José H Urquizo, Ignacio Ferro, Agustina Murgia, Ulyses F J Pardiñas, Juan J Martínez
The rodent Graomys griseoflavus has a wide geographical distribution in the Arid Diagonal of South America, showing variation in the diploid number (2n = 33–38) caused by three different Robertsonian (Rb) translocations. Two contrasting hypotheses have been proposed to explain the origin and evolution of this polymorphism: (i) unique and sequential events; or (ii) multiple and independent origins of Rb translocations. Here, we combined phylogeography and ecological niche modelling to elucidate the evolutionary history of G. griseoflavus and help to contrast these hypotheses. The results indicated a demographic increase that would have begun ~150 kya from the High Monte ecoregion. The spatial distributions of these populations were coincident with the areas of highest habitat suitability. The palaeoclimatic projections suggested the presence of two main glacial refugia coincident with the main genetic clusters. Graomys griseoflavus underwent two pulses of southward expansion at ~220 and ~210 kya. More recently (~20 kya), there was a secondary contact between the southern populations (Low Monte ecoregion) expanding northwards and the northern populations (High Monte ecoregion) expanding into marginal areas of the Chaco ecoregion. Combined with the cytogenetic evidence, our results support the multiple and independent origins of Rb translocations.
{"title":"Phylogeography and ecological niche modelling of the South American cricetid rodent Graomys griseoflavus, with insights into its chromosomal evolution","authors":"José H Urquizo, Ignacio Ferro, Agustina Murgia, Ulyses F J Pardiñas, Juan J Martínez","doi":"10.1093/biolinnean/blad167","DOIUrl":"https://doi.org/10.1093/biolinnean/blad167","url":null,"abstract":"The rodent Graomys griseoflavus has a wide geographical distribution in the Arid Diagonal of South America, showing variation in the diploid number (2n = 33–38) caused by three different Robertsonian (Rb) translocations. Two contrasting hypotheses have been proposed to explain the origin and evolution of this polymorphism: (i) unique and sequential events; or (ii) multiple and independent origins of Rb translocations. Here, we combined phylogeography and ecological niche modelling to elucidate the evolutionary history of G. griseoflavus and help to contrast these hypotheses. The results indicated a demographic increase that would have begun ~150 kya from the High Monte ecoregion. The spatial distributions of these populations were coincident with the areas of highest habitat suitability. The palaeoclimatic projections suggested the presence of two main glacial refugia coincident with the main genetic clusters. Graomys griseoflavus underwent two pulses of southward expansion at ~220 and ~210 kya. More recently (~20 kya), there was a secondary contact between the southern populations (Low Monte ecoregion) expanding northwards and the northern populations (High Monte ecoregion) expanding into marginal areas of the Chaco ecoregion. Combined with the cytogenetic evidence, our results support the multiple and independent origins of Rb translocations.","PeriodicalId":55373,"journal":{"name":"Biological Journal of the Linnean Society","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139951687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-23DOI: 10.1093/biolinnean/blae003
Anthony Herrel, Jody M Taft, Devon C Main, Jessica M da Silva, Krystal A Tolley
Arboreal species tend to have specific adaptations allowing them to effectively negotiate the complexity of their habitats. For example, chameleons have a prehensile tail and limbs adapted to grasping branches. However, the impact of branch diameter and orientation on their movement has been poorly studied. Using ecological, morphological, and pull force data from two species of Bradypodion from different habitats, we examined if chameleons use different substrates and if perch orientation and diameter affect pull strength by quantifying their grip forces on different sized dowels. We found that the habitat of Bradypodion ventrale is homogeneous, and dominated by sparse patches of narrow, vertical perches. For this species, perch diameter significantly affected pull strength in both horizontal and vertical pull directions, with chameleons performing best on a vertical 1.5-mm dowel and a horizontal 3-mm dowel. In contrast, Bradypodion pumilum typically occurs in more variable vegetation, ranging from low shrubs to wooded habitat with high canopy. Our results show that the habitat has perches that are on average wider than for B. ventrale with a greater size range. The performance of B. pumilum was less impacted by perch diameter and pull direction suggesting that B. pumilum is able to use perches of different diameters in their more heterogeneous habitat.
{"title":"Branching out: perch diameter and orientation affect pull strength in chameleons (genus: Bradypodion)","authors":"Anthony Herrel, Jody M Taft, Devon C Main, Jessica M da Silva, Krystal A Tolley","doi":"10.1093/biolinnean/blae003","DOIUrl":"https://doi.org/10.1093/biolinnean/blae003","url":null,"abstract":"Arboreal species tend to have specific adaptations allowing them to effectively negotiate the complexity of their habitats. For example, chameleons have a prehensile tail and limbs adapted to grasping branches. However, the impact of branch diameter and orientation on their movement has been poorly studied. Using ecological, morphological, and pull force data from two species of Bradypodion from different habitats, we examined if chameleons use different substrates and if perch orientation and diameter affect pull strength by quantifying their grip forces on different sized dowels. We found that the habitat of Bradypodion ventrale is homogeneous, and dominated by sparse patches of narrow, vertical perches. For this species, perch diameter significantly affected pull strength in both horizontal and vertical pull directions, with chameleons performing best on a vertical 1.5-mm dowel and a horizontal 3-mm dowel. In contrast, Bradypodion pumilum typically occurs in more variable vegetation, ranging from low shrubs to wooded habitat with high canopy. Our results show that the habitat has perches that are on average wider than for B. ventrale with a greater size range. The performance of B. pumilum was less impacted by perch diameter and pull direction suggesting that B. pumilum is able to use perches of different diameters in their more heterogeneous habitat.","PeriodicalId":55373,"journal":{"name":"Biological Journal of the Linnean Society","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139951690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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