The effect of developmental temperature on population flexibility in Drosophila melanogaster and D. simulans

Abstract

Ten strains each of D. melanogaster and D, simulans were derived from single inseminated females of the same population. For each strain the influence of developmental temperatures in the range 12-30°C was considered for developmental time, egg to adult development percentage, sex ratio, longevity of adults, mating speed, fecundity and fertility. The species showed similar responses for all characters, although for the latter four D. simulans was more affected by extreme temperatures. Analyses of variance demonstrated temperature, strain, and temperaturex strain effects to be generally significant. For sex ratio, however, temperature effects alone were significant. The results are discussed in relation to the level of genetical integration existing in a population and how such integration allows for considerable population flexibility.

Within- and between-generation effects of temperature on early fecundity of Drosophila melanogaster

“…This buffering is somewhat surprising, given that females developing at the lower end of this range are much larger in body size than those developing at 25°C (e.g. David et al, 1983) and that large females are often relatively fecund (Robertson, 1957). Fecundity is, however, clearly reduced following development at extreme temperatures (Lints & Lints, 1971;McKenzie, 1978;Cohet & David, 1978). Cohet & David (1978) showed that this reduction reflects either low ovariole number (at high developmental temperature) or a lower rate of oogenesis (at low developmental temperature).…”

“…In pilot experiments, the viability of eggs was very high and independent of develop-mental temperature (see also David & Clavel, 1967;McKenzie, 1978). Moreover, given that the heritability of fecundity is generally low (see table 1 in Roff & Mousseau, 1987), any selection during this experiment should have minimal effects.…”

“…Fecundity is also strongly influenced by environmental factors such as crowding and temperature (Robertson & Sang, 1944;David et al, 1983). Fecundity in Drosophila, for example, may depend not only on the temperature a female experiences as adult (Dobzhansky, 1935;David et al, 1983), but also on the temperature she experienced during development: thus females raised at extremely low or high temperatures are typically less fecund than are females raised at intermediate temperatures (Lints & Lints, 1971;Cohet & David, 1978;McKenzie, 1978).…”

Environment-dependent fitness differences in Drosophila melanogaster: temperature, domestication and the alcohol dehydrogenase locus

“…The adults remained in the bottles for 240 hours at 15°C, 65 hours at 20°C, 35 hours at 25°C and 30 hours at 29°C after which time they were discarded. These periods were chosen on the basis of McKenzie (1978) and ensured that similar egg, larval and adult densities obtained at each temperature. After establishment, the populations were maintained in discrete generations as follows: The subsequent generation was monitored daily and when approximately 350 to 450 adults had emerged, these were transferred to a fresh bottle.…”

Ethanol tolerance and alcohol dehydrogenase activity in Australian populations of Drosophila simulans

“…However, the little experimental evidence available suggests that this is not the case; D. simulans in fact shows less developmental flexibility under various temperature regimes (Levins, 1969;McKenzie, 1978). An alternative explanation for the lower level of genetic variation between populations of D. simulans is that migration rates are higher in this species; however we are unaware of any data to test this proposition.…”