E. Turak et al., DIFFERENT RESPONSES TO TEMPERATURE IN 3 CLOSELY-RELATED SYMPATRIC CEREAL APHIDS, Entomologia experimentalis et applicata, 86(1), 1998, pp. 49-58
Chromosomal races of the aphid Sitobion miscanthi (Takahashi), and a c
losely-related species S. near fragariae (Aphididae: Macrosiphini) sho
w seasonal differences in abundance in eastern Australia. We tested wh
ether this was related to differences in temperature response, using c
ontrolled laboratory conditions. Intrinsic rate of increase, tau(m), m
ean relative growth rate (MRGR), and longevity were compared at differ
ent temperatures, and rates of increase were compared outdoors under a
mbient conditions. Using laboratory data, we simulated population grow
th, for comparison with outdoor populations. There were significant di
fferences in responses to temperature regimes both in the laboratory a
nd outdoors. Outdoor populations fell well short of predicted sizes. S
. miscanthi (2n = 18) showed evidence of adaptation to warmer conditio
ns. In contrast, S. nr fragariae showed consistent evidence for adapta
tion to cooler conditions, and S. miscanthi 2n = 17 was approximately
intermediate. These data indicate that temperature responses are impor
tant in the ecology, evolution and pest status of S. miscanthi clones
and S. nr fragariae in Australia.