Temperature effects on pupation-height response in four Drosophila species group triads

A comparison of pupation-height responses among four Drosophila species group triads ( virilis, repleta, melanogaster and willistoni) was carried out in the laboratory at temperatures ranging from 4.5 to 38°C and 100% r.h. The effects of temperature on pupation-height response appear complex in the species groups examined. Two-way analyses of variance (species × temperature) reveal that significant effects differ for each triad. At temperatures where at least 50% pupation success was observed, mean pupation heights are low for all species (less than 5 mm). At high-temperature extremes, all species show little or no upward movement. At low-temperature extremes, maximal height is observed in some species within the repleta and willistoni groups, and the entire melanogaster triad. However, other species within the repleta and willistoni groups, and the entrie virilis triad show no upward movement at all under the same low-temperature conditions. A species' pupation-height response at one temperature extreme cannot be used to predict its response at the other temperature extreme. Temperature effects on pupation height in one species do not necessarily reflect the effects on other species within the group. Temperature effects for one species group cannot be used to predict responses for other groups from different phylogenetic and ecological backgrounds.