Are development and growth of pea aphids, Acyrthosiphon pisum, in North America adapted to local temperatures?

Abstract

Developmental rate and adult weight were studied at constant temperatures from 9.8 to 27.9°C for 18 clones from each of five populations of the pea aphid, Acyrthosiphon pisum (Harris), from locations between 39 and 53°N latitude in central North America. The response of developmental rate to temperature for each clone was accurately described by a three parameter non-linear equation. Adult weight usually decreased with increasing rearing temperature, but the shape of the response to temperature varied among clones. Variation in the developmental parameters was greater among clones within populations than among populations. No consistent trends were observed in the developmental parameters or adult weights either with latitude or the long term average temperatures at the locations. We conclude that previously reported geographic variation in the developmental threshold of this species, which was attributed to local adaptation, occurred either because the clones tested were not representative of the populations or because rearing methods differed among studies. The results are discussed in relation to the hypothesis that life history traits which are temperature sensitive are adapted to local thermal environments.

First demonstration of the influence of photoperiod on the thermal requirements for development in insects and in particular the linden-bug, Pyrrhocoris apterus (Heteroptera: Pyrrhocoridae)

“…This feature allows the calculation of the coefficient of linear regression (CLR) of development rate on temperature (the slope of the regression line), the so-called lower developmental threshold or thermal threshold for development (TTD) -the theoretical minimum temperature at which development will proceed assuming a linear relationship between development rate and temperature, and the sum of effective temperatures (SET) or the number of day-degrees above thermal threshold needed to complete development (Campbell et al, 1974;Ratte, 1985). The TTD and SET are widely used and important life-history traits, especially in comparative studies of the adaptations of insect species and populations to local environmental conditions (Campbell et al, 1974;Lamb et al, 1987;Tauber et al, 1987Tauber et al, , 1988Hon k & Kocourek, 1990;Hon k, 1996a,b). This is why linear regression analysis was used in this study.…”

Reaction norm in response to temperature may change to adapt rapid brood development to boreal and subarctic climates in Myrmica ants (Hymenoptera: Formicidae)

“…the number of day-degrees above thermal threshold needed to complete development (Campbell et al, 1974;Ratte, 1985). The TTD and SET are widely used as important life-history traits, especially in comparative studies, usually to examine and illustrate the adaptations of insect popu lations to local environmental conditions (Campbell et al, 1974;Lamb et al, 1987;Tauber et al, 1987Tauber et al, , 1988Honek & Kocourek, 1990;Honek, 1996a, b). This is why we also used linear regression analysis in our study.…”

Measuring and reporting life-cycle duration in insects and arachnids

“…Most of the results of different authors on the same species are different because there were minor differences in factors such as diet (cf. Lamb et al, 1987).…”

“…For example, the morphs, colour forms, and even clones of aphids develop at different rates (Araya et al, 1996). Such clonal differences may lead to erroneous conclusions that there are geographical or population differences (Lamb et al, 1987). The preoviposition period differs between individuals with different dispersal capabilities (some examples are given above under Adult stage; see also Spence, 1989 andSocha &Sula, 1998 for macropterous and brachypterous morphs of some heteropterans).…”