Files
Abstract
Nectar is the primary energy source for most adult butterflies and is critical for their survival and reproduction. Changes in nectar abundance and phenology could be particularly important for migratory insects like monarch butterflies, for which declines in overwintering numbers have been observed. We examined how nectar quality and quantity affect adult monarch weight, survival, fecundity, and flight performance. Additionally, we asked whether nectar quality interacts with infection to affect monarch fitness and flight. Adults provided with reduced nectar resources had lower weight, survival, and fecundity. These effects were stronger for reproductive (vs. migrant) monarchs. Weak negative effects of nectar limitation were observed for monarch flight, and infection by a protozoan parasite did not intensify the effects of nectar limitation. These findings indicate that migrants can withstand nectar limitation better than summer breeding monarchs. Future work is needed to understand how nectar resources interact with other environmental stressors monarchs face.