Temperature effects on Mormon cricket Anabrus simplex embryo development, hatching and nymphal growth: Thermal performance curves change with ontogeny

Abstract

Thermal performance curves for development are an essential tool for population modeling and pest management. More broadly, they characterize how selection on thermal limits or maximum rates change with life stage. The effects of temperature on development of Mormon cricket embryos, and hatching and development of nymphs were measured on a population from the Bighorn Mountains of Wyoming and modeled with four non-linear equations. Taylor's Gaussian curve characterized embryonic development, which was most rapid at 26.9 °C. However, half-grown embryos aestivated at high temperatures, resulting in a significant shift in the optimum temperature to complete embryonic development to 24.1 °C and a reduction in the breadth of the performance curve (thermal breadth). Fully grown embryos hatched fastest at relatively low temperatures (21.8 °C), whereas nymphal development was maximized at relatively high temperatures (35.7 °C). Thermal breadths for nymphal hatching and development were also significantly broader than that for embryonic development. Differences in optimum temperature and thermal breadth of each life stage should be taken into consideration in population modeling, comparisons among populations, and epigenetic studies of acclimation.