Energetics and Reproduction in Female Scaphiopus multiplicatus from Western Texas

Abstract

Survival of spadefoot toads in semi-arid regions of the southwestern United States has been attributed, in part, to their adaptation of a sporadic, rainfallstimulated activity regime (Bentley, 1966; McClanahan, 1967; Ruibal et al., 1969; Seymour, 1973a). Furthermore, the annual duration of this intermittent activity may be quite brief (e.g., 2 mo, Seymour, 1973b) and during this time all mating and foraging for the year must occur. Several studies examined the use of lipid as an energy storage substrate in spadefoots (Seymour, 1973b; Dimmitt and Ruibal, 1980; Jones, 1980); however, due to the brevity of the species' annual activity, these studies consisted of only a few months of observation during the year. In general, spadefoots conformed to the hypotheses concerning energy use strategies which predict low levels of stored energy in ectotherms exiting dormancy, continuance of low levels during vitellogenesis, followed by an increase in levels prior to brumation (e.g., Derickson, 1976; Fitzpatrick, 1976). The purpose of this study was to observe the seasonal variation of somatic and ovar-