Narrow oviposition preference of an insect herbivore risks survival under conditions of severe drought

1. Understanding species' habitat preferences are crucial to predict organisms'
responses to the current climate crisis. In many insects, maternal habitat selection for oviposition essentially determines offspring performance. Whether future changes in climatic conditions may generate mismatches between oviposition preference and offspring performance, when mothers continue to prefer microhabitats that might threaten offspring survival, is an open question.
2. To address this gap, we tested if oviposition preferences of the Glanville fritillary butterfly Melitaea cinxia females put offspring at risk when plants are under drought stress conditions. Mainly, we focus on identifying the microhabitat determinants for oviposition and the variation of conditions experienced by the sessile offspring, using field observations from 12 populations collected over 2015–2018. These data are combined with 10 years of larval nest and precipitation data to understand within-population patterns of habitat selection. We tested whether the preferred microhabitats maximized the extended larval performance (i.e. overwinter survival).
3. We found that females preferentially oviposited in microhabitats with higher host plant abundance and higher proportion of host plants with signs of drought stress. In most years, larval nests had higher survival in these drought-stressed microhabitats. However, in an extremely dry year, only two nests survived over the summer.
4. Our results highlight that a failure to shift habitat preference under extreme climate conditions may have drastic consequences for the survival of natural populations under changing climatic conditions.