Nectar resource limitation affects butterfly flight performance and metabolism differently in intensive and extensive agricultural landscapes

Flight is an essential biological ability of many insects, but is energetically costly. Environments under rapid human-induced change are characterized by habitat fragmentation and may impose constraints on the energy income budget of organisms. This may, in turn, affect locomotor performance and willingness to fly. We tested flight performance and metabolic rates in Meadow brown butterflies (Maniola jurtina) of two contrasted agricultural landscapes: intensively managed, nectar-poor (IL) versus extensively managed, nectar-rich landscapes (EL). Young female adults were submitted to four nectar treatments (i.e. nectar quality and quantity) in outdoor flight cages. IL-individuals had better flight capacities in a flight mill and had lower resting metabolic rates (RMR) than EL-individuals, except under the severest treatment. Under this treatment, RMR increased in IL-individuals, but decreased in EL-individuals; flight performance was maintained by IL-individuals, but dropped by a factor 2...