Factors affecting reproductive output of Mediterranean geckos, Hemidactylus turcicus (Sauria, Gekkonidae)

Abstract

An investigation was conducted on factors which potentially influence reproductive output of Hemidactvlus turcicus. This study concentrated on three topics: 1) lipid cycles, 2) maternal investment, and 3) parasitic infection.

The reproductive season of 1983 extended from March through September. Most females were reproductively active for 120-150 days and probably produced 2-3 clutches during this time. Fatbodies were rapidly depleted at the onset of vitellogenesis and remained at low levels throughout the reproductive season. Carcass lipid levels were reduced at the start of reproduction and during production of later clutches. Apparently, energy from ingestion was insufficient to assure formation of later clutches and fatbody and carcass lipid reserves were drawn upon for supplemental energy. The evidence indicated these lipids were mobilized to the liver, probably for use In vitellogenin production.

The fatbody cycle of males was inversely related to the testicular cycle. Carcass lipid and liver lipid levels of males increased during testicular regression and decreased during testicular enlargement. This pattern of storage and utilization of lipids indicates that there was a surplus of energy during testicular regression and a deficit during testicular recrudescence. Fatbodies and carcass lipid of males were also utilized at the start of the female reproductive season, probably to provide males with supplemental energy during breeding.

Egg size was not related to female body size or timing of reproduction. However, egg size was positively correlated with hatchling size. Under laboratory conditions, there was no variation in egg size between groups of females maintained at different food regimens. Also, there was no difference in egg size between first and second clutches of experimental females. The data on K turcicus did not support the hypothesis that factors normally influencing clutch size in variable clutch species might similarly influence egg size in fixed clutch species.

Forty-three percent of adult Hemidactvlus turcicus from southern Texas were infected with a pulmonary pentastome. Raillitiella frenatus. Liver mass during the nonreproductive period and fatbody mass during the reproductive season were significantly lower in individuals of both sexes with the highest biomass of pentastomes. Uninfected females had a significantly higher frequency of oviductal eggs than infected geckos. Oviductal egg production in this gecko population was reduced by 21 % because of the pentastome infection. These data indicate that this macroparasitic infection should be considered a factor in the population regulation of H- turcicus in southern Texas.