- Does Less - than - annual Production of Offspring

Abstract

Copulation does not necessarilyresult in the production of offspring. Copulatory behavior unrelated to reproductive output has been recorded in a wide variety of species (e.g., Hrdy, 1986; De Ruiter et al.' 7994; Polimaa-et al., 1995). These non-reproductive matings have been interpreted as nonadaptive by some workers (e.g., as consequences of high sex-steroid levels: e.g.,'Symons, lgTgib:ut as adapiations by others. For eiamole. females that mate more often than is necessarv ior reproduction may enhance their nutritional status through nuptial fifts or sperm acquisition (Ward and Landol! 1995) or may be able to manipulate the subsequent behavior of their male partners (Hrdv 1986; De Ruiter et al., 1994). Because studies on rbptiles have generally interpreted coprrlations with fbmales strictly in terms of sperm transfer, most herpetologists have tacitly assumed that mating only occurs in circumstances where the sperm that are transferred are likely to contribute to paternity of a femalds offspring. The inference is logical and plausible but definitive evidence is weak. Snakes with less-than-annual frequencies of female reproduction offer an excePtional opPortunity to examine this question. In many species ofsnakes, -especially viperids from temPerate zone habitats, adult ?emalei do not produce offspring every year. Instead, females delay the production of their next litter until they have accumulated sufficient body reserves/ a Process that may take from one to several years (e.g., Saint Girons, 1957; Fitch, 1960a; Browry 1991). In consequenca the population each year contains bolh-1epr6ductive and non-reproductive females. We define is "reoroductivd' those females whidn contained large (>10 mm diameter) vitellogenic follicles or embryos (detected by palpation or observed at parturition). Females were classified as "Non-reproductivd' if they were caught without enlarged ova or embryos during the period of vitellogenesis and/or gestation (Bonrret and Naulleart 1996a). This definition is strictlv based on physiological events (Bonnet et a1.,1994), Jnd thus is sorirewha't different from a purely behavioral one (e.g., "sexually activd' versus "non sexually activd' femiles). This clarification is important because the concepts of "reproductivd' versus "sexually

Cite this paper

@inproceedings{Shine2005DL, title={- Does Less - than - annual Production of Offspring}, author={Richard Shine and OLivER LoURDAISI}, year={2005} }