Temperature-dependent regulation of diapause and hatching success in aphids: implications for climate change

Diapause is a crucial adaptive strategy that enables insects, including aphids, to survive unfavorable environmental conditions, particularly during winter. Diapause of aphids takes the form of facultative and embryonic diapause occurring in the eggs. This study investigates the diapause dynamics of aphids, based on Maculolachnus submacula (Walker), at 3 different temperatures to assess the impact of elevated temperatures on embryonic development and hatching success. To determine the diapause strategy and to detect dividing cells, immunostaining was performed. M. submacula exhibited a slow embryonic development strategy during diapause, with mitotic activity and body growth occurring at all tested temperatures. Embryos incubated at higher temperatures achieved greater body length and leg proportions. Higher temperatures accelerated embryonic development, leading to earlier hatching. Hatching success was temperature-dependent, with the highest percentage of hatched individuals at 0 °C and lower success at 10 °C. Premature hatching at higher temperatures resulted in increased rates of developmental abnormalities of the embryo bodies and egg cracking disorder. Survival of nymph rates was low, with mortality reaching 63.5% in natural conditions. These findings highlight the significant influence of temperature on diapause progression, embryonic development, and survival. The conducted studies indicated that an increase in ambient temperature in winter affects aphids with a diapause strategy, characterized by slow development of embryos during winter diapause. Rising global temperatures due to climate change make the understanding of the effects of increasing temperatures on aphid diapause essential for predicting shifts in population dynamics, pest outbreaks, and ecological interactions.