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Thermal limits to survival and activity in two life stages of false codling moth Thaumatotibia leucotreta ( L epidoptera, T ortricidae)
Author(s) -
Terblanche John S.,
Mitchell Katherine A.,
Uys Wilmari,
Short Clancy,
Boardman Leigh
Publication year - 2017
Publication title -
physiological entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 57
eISSN - 1365-3032
pISSN - 0307-6962
DOI - 10.1111/phen.12210
Subject(s) - biology , phenotypic plasticity , larva , acclimatization , zoology , botany , ecology
The present study examines life stage‐related variation in the thermal limits to activity and survival in an A frican pest, the false codling moth Thaumatotibia leucotreta ( L epidoptera, T ortricidae). Thermal tolerance, including the functional activity limits of critical thermal maxima and minima ( CT max and CT min respectively), upper and lower lethal temperature, and the effect of heat and cold hardening (short‐term acute plasticity), is measured across a diverse range of low or high temperature stress conditions in both larvae and adults. We also report the sum of inducible and cognate forms of the amounts of heat shock protein 70 ( HSP 70) as an explanatory variable for changes in thermotolerance. The results show that the larvae have high variability in CT max and CT min at different ramping rates and low levels of basal (innate) thermal tolerance. By contrast, the adults show high basal tolerance and overall lower variability in CT max and CT min , indicating lower levels of phenotypic plasticity in thermotolerance. HSP 70 responses, although variable, do not reflect these tolerance or survival patterns. Larvae survive across a broader range of temperatures, whereas adults remain active across a broader range of temperatures. Life stage‐related variation in thermal tolerance is most pronounced under the slowest (most ecologically‐relevant) ramping rate (0.06 °C min –1 ) during lower critical thermal limit experiments and least pronounced during upper thermal limit experiments. Thus, the ramping rate can hinder or enhance the detection of stage‐related variation in thermal limits to activity and survival of insects.