Longer daylengths associated with poleward range shifts accelerate aphid extinction by parasitoid wasps

Climate change is causing the poleward range-shift of many species, with consequent modifications to daylight regimes and potential impacts on light-cycle activity patterns ecological interactions. Day-active parasitoids experiencing longer summer days associated a range shift display increased attack rates their aphid hosts have higher lifetime fecundity. Theory consequently predicts that increasing photoperiod, host–parasitoid interactions would become less stable more variable population densities extinction probability. To test this prediction empirically, we conducted multigenerational aphid-parasitoid microcosm experiment in which followed dynamics under 14 18 h treatments. As predicted, found an rate both aphids daylengths. The long-day treatments also exhibited temporal variation parasitoid numbers cumulative size, consistent extinctions are due rates. Our results demonstrate light regime can affect interacting species potentially limit co-existence parasitoids, as well other trophically taxa where dependent regime. This highlights importance rarely considered effect changing conditions climate change–driven shifts, could shifts