Unraveling the mating system of the burrowing shrimp Lepidophthalmus siriboia (Decapoda Callichiridae) based on life history traits

Abstract

AbstractNatural history studies are important in helping to understand the origin and evolution of social organization as well as the evolution of specialized morphological structures linked to mating behavior of animals. Here we describe the burrow use pattern, sex ratio, and sexual dimorphism of the burrowing shrimp Lepidophthalmus siriboia to test a series of evolutionary hypotheses. To this end, a total of 259 individuals of L. siriboia were collected from the northeast region of Brazil. No shrimp pairs or burrows inhabited by more than one shrimp were detected during the study period. A solitary habit is a non-random behavior in this species because single shrimps were found with a greater frequency than expected by chance. All ovigerous females were found living solitarily, which suggests that males abandon these females shortly after insemination. Contrary to the expectations of an anisogamous species, L. siriboia produced a female-biased operational sex ratio (OSR), contradicting the hypothesis that only males compete for mates. The latter was supported by the existence of sexual dimorphism in cheliped size, a condition that argues in favor of female–female competition in this species. In the same line of reasoning, heterochely was present in adult males, although it was also present to a lesser degree in adult females. Female asymmetry of chelipeds suggests the evolution of an unconventional role in female major cheliped use. The major cheliped showed a positive allometric growth pattern through the ontogeny of both sexes. However, when growth patterns of the major and minor chelipeds were compared, the fitted regression lines for each sex had different slopes, indicating that the cheliped could be an appendage sexually selected by individuals of the opposite sex during mating.Key Words: allometric growthanimal weaponsmating successsex ratiosexual selection ACKNOWLEDGMENTSThe lead author is grateful to Rozana Lima and her son Bryan Lima for the help during sampling activities. The material described herein was collected during the project entitled ‘História de vida dos camarões-fantasma (Decapoda, Axiidea, Anacalliacidae-Callianassidae-Callichiridae-Ctenochelidae) do Brasil: taxonomia, estilo de vida, dimorfismo sexual e sistema de acasalamento’. Finally, we deeply thank to two anonymous referees, who helped to improve the content and format of the manuscript.DISCLOSURE STATEMENTNo potential conflict of interest was reported by the authors.ETHICAL STANDARDAll applicable international, national and/or institutional guidelines for the care and use of animals were followed by the authors. All necessary permits for sampling and observational field studies were obtained by the authors from the competent authorities. Licenses to collect zoological material issued to P. Hernáez (#51,578-1, #58,845-1) were provided by the Brazilian Institute of the Environment and Renewable Natural Resources (SISBIO/IBAMA-MMA).AUTHOR CONTRIBUTIONP. Hernáez conceived the idea for this study; P. Hernáez and J.F. Souza-Filho collected the data; P. Hernáez and A. Forbes analyzed the data; P. Hernáez, A. Forbes, P.R.C.M. de Souza and J.F. Souza-Filho wrote the paper.SUPPLEMENTAL DATASupplemental Data for this article can be accessed at https://doi.org/10.1080/03949370.2023.2248086DATA ACCESSIBILITYAll data related to this article will be included in the Supporting Information openly available in the Figshare Repository https://doi.org/10.6084/m9.figshare.23060786.v2Additional informationFundingWe are grateful to ‘Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco (FACEPE)’ for financial aid through a Researcher Fixation Scholarship for P. Hernáez [process BFP-0196-1.08/20], and for providing funding in the form of a scientific initiation fellowship for P.R.C.M. de Souza [#BIC-0082-2.05/22].