Experimental evidence for stronger impacts of larval but not adult rearing temperature on female fertility and lifespan in a seed beetle

Abstract

Temperature impacts behaviour, physiology and life-history of many life forms. In many ectotherms, phenotypic plasticity within reproductive traits could act as a buffer allowing adaptation to continued global warming within biological limits. But there could be costs involved, potentially affecting adult reproductive performance and population growth. Empirical data on the expression of reproductive plasticity when different life stages are exposed is still lacking. Plasticity in key components of fitness (e.g., reproduction) can impose life-history trade-offs. Ectotherms are sensitive to temperature variation and the resulting thermal stress is known to impact reproduction. So far, research on reproductive plasticity to temperature variation in this species has focused on males. Here, I explore how rearing temperature impacted female reproduction and lifespan in the bruchid beetle Callosobruchus maculatus by exposing them to four constant temperatures (17 °C, 25 °C, 27 °C and 33 °C) during larval or adult stages. In these experiments, larval rearing cohorts (exposed to 17 °C, 25 °C, 27 °C and 33 °C, from egg to adulthood) were tested in a common garden setting at 27 °C and adult rearing cohorts, after having developed entirely at 27 °C, were exposed to four constant rearing temperatures (17 °C, 25 °C, 27 °C and 33 °C). I found stage-specific plasticity in all the traits measured here: fecundity, egg morphological dimensions (length and width), lifespan and egg hatching success (female fertility). Under different larval rearing conditions, fecundity and fertility was drastically reduced (by 51% and 42%) at 17 °C compared to controls (27 °C). Female lifespan was longest at 17 °C across both larval and adult rearing: by 36% and 55% compared to controls. Collectively, these results indicate that larval rearing temperature had greater reproductive impacts. Integrating both larval and adult rearing effects, I present evidence that female fertility is more sensitive during larval development compared to adult rearing temperature in this system.

Pre-fertilization gamete thermal environment influences reproductive success, unmasking opposing sex-specific responses in Atlantic salmon ( Salmo salar )

“…Similarly, eggs are highly sensitive to temperature experienced before fertilization [ 41 ] where higher temperatures resulted in reduced production (e.g. [ 42 ], bed bug Cimex lectularius ) , larger [ 15 ] ( T. castaneum ) or smaller egg sizes [ 43 ] ( C. maculatus ), reduced fertilization capability (e.g. [ 44 ], Bos taurus ) and lower offspring fitness including lower survival rates (e.g.…”

Parental exposure to heat waves improves offspring reproductive investment in Tetranychus urticae (Acari: Tetranychidae), but not in its predator, Phytoseiulus persimilis (Acari: Phytoseiidae)

“…Consequently, selection should favor smaller egg sizes, which also enables females to invest more in the number of eggs (Sibly & Calow, 1983 ; Taylor & Williams, 1984 ; Yampolsky & Scheiner, 1996 ). Deviations from this trend are documented for crickets [higher number and larger size of eggs (Stahlschmidt et al., 2022 )], lizards [higher egg number but insensitive egg sizes (Hall & Warner, 2017 )], butterflies [lower egg number and smaller size (Janowitz & Fischer, 2011 )] and beetles [both egg number and size are insensitive (Vasudeva, 2023 )]. However, temperature also indirectly influences egg size and egg number through the maternal phenotype (Angilletta Jr, 2009 ).…”