Asynchronous oviductal seasonal variation in the unisexual-bisexual Nactus pelagicus complex from the Vanuatu Archipelago (Reptilia: Squamata: Gekkonidae)

Mallory E. Eckstut, Southeastern Louisiana University
Alison M. Hamilton, Louisiana State University
Christopher C. Austin, Louisiana State University
David M. Sever, Southeastern Louisiana University


The South Pacific Nactus pelagicus complex (Reptilia: Squamata: Gekkonidae)consists of several genetically distinct but morphologically conserved lineages of N.multicarinatus, and a unisexual lineage, N. pelagicus, which is a hybrid of two N.multicarinatus lineages. A few discrete morphological differences occur betweenlineages of the N. pelagicus complex, but that is all that is known regarding this complex.This complex has been poorly studied and little is known about the general biology andecology of N. pelagicus and N. multicarinatus. We analyzed the reproductivemorphology using histochemistry in populations of N. multicarinatus and N. pelagicusfrom the Vanuatu Archipelago in the South Pacific, the only series of islands where thetwo species overlap, in order to determine if interspecific differences in reproductivepatterns exist and to gather additional knowledge regarding the reproductive ecology ofthese species. Our findings indicate that both species carry one clutch during the dryseason, however there is temporal variation in reproductive activity, with N. pelagicusexhibiting particular histochemical states one and a half to two months prior to N.multicarinatus. Furthermore, we found that N. multicarinatus, the bisexual lineage, doesnot store sperm with eggs in utero, which has only been observed in one other species oflizard (a skink). These previously unrecognized differences in Nactus reproductionprovide a foundation for further study of the evolutionary transition to unisexualreproduction and supply additional data on the ecology of this poorly studied geckocomplex. © 2009 Nova Science Publishers, Inc. All rights reserved.