Reproductive patterns of endemic island lanceheads: evolution and conservation

• Grant number: 24/09562-6
• Support Opportunities: Regular Research Grants
• Start date: February 01, 2025
• End date: January 31, 2028
• Field of knowledge: Biological Sciences - Zoology - Physiology of Recent Groups
• Principal Investigator: Selma Maria de Almeida Santos
• Grantee: Selma Maria de Almeida Santos
• Host Institution: Instituto Butantan. Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil
• Associated researchers: Henrique Bartolomeu Pereira Braz ; Otavio Augusto Vuolo Marques
• Associated scholarship(s): 25/03261-7 - Development and Implementation of a Data Management System for Studies on the Reproduction and Conservation of Insular Jararacas, BP.TT

Abstract

Organisms that inhabit islands differ predictably from their continental counterparts in a number of ecological, morphological, behavioral, demographic and reproductive characteristics. These differences are collectively referred to as the "island syndrome". Although this phenomenon has been consistently described in a wide variety of animal and plant species, recent comparative evidence has questioned whether such changes occur in small reptiles. Moreover, a clear pattern of changes in reproductive strategies among insular reptiles has yet to be established. This project has two main aims. Firstly, we will characterize the reproductive strategies of five lancehead species endemic to islands in southeastern Brazil. Specifically, we will investigate fecundity, minimum body size at sexual maturity, sexual dimorphism, reproductive season, and the intriguing presence of male copulatory organs (hemipenes) in females of these species. Based on these data, we will compare the reproductive strategies of island lancehead populations with those of the common lancehead (their closest mainland relative) to test several predictions derived from the "island syndrome" hypothesis. We will address four questions derived from this hypothesis: (1) Are the reproductive strategies of island lanceheads "slower" than those of the mainland lancehead? (2) Does the dwarfism observed in all insular lancehead species affect the magnitude of sexual size dimorphism? (3) Does the reproductive season of island lanceheads differ from that of the mainland lancehead? (4) What is the frequency of females with hemipenes in the different species of insular lanceheads? The second objective of this project is to contribute to the development of management and conservation strategies for island lanceheads, both in situ and ex situ. We will accomplish this in two ways: (1) by establishing populations of island lanceheads at the Laboratory of Ecology and Evolution at the Instituto Butantan and implementing a captive breeding program. (AU)