Effects of heat stress on copulation, fecundity and longevity of newly-emerged adults of the predatory mite, Neoseiulus barkeri (Acari: Phytoseiidae)

Climate change predictions depict scenarios where arthropods will be more intensely and frequently exposed to extreme high temperatures. A short period of heat stress is unlikely to cause directly mortality but may modify population dynamics via impacting life history traits. In this study, the newly-emerged female and male adults of the predatory mite, Neoseiulus barkeri Hughes (Acari: Phytoseiidae) were exposed to 42 degrees C for 4 hours to investigate the heat effects on the copulation, longevity, fecundity and egg hatchability through parental effects of the mite. The results showed that after heat stress, the females had a markedly extended pre-oviposition period, shortened oviposition period, and reduced fecundity and longevity. At the meantime, when females mated with the heat stressed males, the pre-oviposition period was prolonged, the oviposition period was shortened and the fecundity was reduced. A sex-specific effect of short term heat exposure on mating behavior was further observed in males where copulation duration of the stressed individuals were somewhat prolonged. In addition, a trade-off between survival and reproduction was observed in heat stressed females. However, heat stress had no effects on immediate mortality, pre-copulation period, post-oviposition period, male longevity and egg hatchability of the progeny generations. Our results confirmed that heat stress had a detrimental effect on reproduction, particularly by delaying the onset of oviposition and reducing reproductive output and thereby influencing the population dynamics of N. barkeri.