Can laboratory-reared aphid populations reflect the thermal performance of field populations in studies on pest science and climate change biology?

Laboratory insect rearing provides well-developed tested insects for research in general biology, pest science and development of pest management technology and products. The effects of environmental conditions on various traits in laboratory populations are often extrapolated to field populations; for example, the thermal performances of laboratory populations are used to predict the phenology and abundance of wild pest populations. However, these studies generally do not consider the potential rapid evolution of the laboratory populations. Therefore, it is not certain whether laboratory populations reflect the performance of field populations in natural fluctuating and sometimes extreme conditions. Here, we used a global insect pest, the English grain aphid [Sitobion avenae (Hemiptera: Aphididae)] as the model system, to compare the demography of field and laboratory populations experimentally under constant and ecologically relevant fluctuating temperatures. Our results indicated that the field population adapted better to fluctuating temperatures and high temperatures. By contrast, the laboratory population adapted better to mild constant temperatures but reduced ability to withstand extremely high temperatures under diurnal fluctuations and chronic high temperatures. Therefore, caution is needed when extending the ecological effects of temperature from laboratory populations to wild populations, especially in environments with extreme events. Laboratory populations require regular replenishing or rearing under fluctuating temperature conditions to maintain the genetic diversity and prevent rapid adaptation to rearing environments.