Low temperature thresholds: are chill coma and CT(min) synonymous?

The effects of sub-lethal low temperatures on insect physiology and behaviour are important determinants of insect activity including foraging, mating, and predation avoidance. A substantial body of research seeks to relate the temperatures at which these activities are compromised to both, climatic conditions at species range limits and underlying physiological processes. The interpretation of this research is complicated by confusion in the names and definition of the responses measured and their associated temperature thresholds.

Hyperthermic aphids: insights into behaviour and mortality.

Although the impact of warming on winter limitation of aphid populations is reasonably well understood, the impacts of hot summers and heat wave events are less clear. In this study, we address this question through a detailed analysis of the thermal ecology of three closely related aphid species: Myzus persicae, a widespread, polyphagous temperate zone pest, Myzus polaris, an arctic aphid potentially threatened by climate warming, and, Myzus ornatus, a glasshouse pest that may benefit from warming. The upper lethal limits (ULT(50)) and heat coma temperatures of the aphid species reared at both 15 and 20 degrees C did not differ significantly, suggesting that heat coma is a reliable indicator of fatal heat stress.

A comparison of low temperature tolerance traits between closely related aphids from the tropics, temperate zone, and Arctic.

The survival of aphids exposed to low temperatures is strongly influenced by their ability to move within and between plants and to survive exposure to potentially lethal low temperatures. Little is known about the physiological and behavioural limitations on aphid movement at low temperatures or how they may relate to lethal temperature thresholds. These questions are addressed here through an analysis of the thermal ecology of three closely related aphid species: Myzus persicae, a ubiquitous temperate zone pest, Myzus polaris, an arctic species, and Myzus ornatus, a sub-tropical species.