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

Abstract

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 2.5 in EL individuals. IL individuals had more canalized (i.e. less plastic) responses relative to the nectar treatments than EL individuals. Our results show significant intraspecific variation in the locomotor and metabolic response of a butterfly to different energy income regimes relative to the landscape of origin. Ecophysiological studies help to improve our mechanistic understanding of the eco-evolutionary impact of anthropogenic environments on rare and widespread species.

High cover of forest increases the abundance of most grassland butterflies in boreal farmland

“…Recent studies in Northern Europe have shown that even production forestry clear-cuts, which have long been considered to make up an unsuitable matrix for butterflies, provide valuable habitats for many butterfly species (Blixt et al, 2015;Viljur & Teder, 2016). Besides the amount of nectar available, nectar quality is also important for butterflies (Lebeau et al, 2016). High cover of forest in the surrounding landscape may also enhance the availability of resources in traditional grassland habitats ( € Ockinger et al, 2012b).…”

Functional traits in red flour beetles: the dispersal phenotype is associated with leg length but not body size nor metabolic rate

“…; Killen et al . , ; Lebeau, Wesselingh & Van Dyck ; Metcalfe, Van Leeuwen & Killen ). Variation in MR is maintained in most natural populations allowing for different strategies for growth, behaviours and reproduction in specific contexts (Burton et al .…”

Ecotypic differentiation matters for latitudinal variation in energy metabolism and flight performance in a butterfly under climate change

“…Although much of this work was developed with endothermic vertebrates as study systems, the issue of energy management in ectotherms (including flying heliotherms like butterflies) and what that signifies for the assumption of the use of SMR as proxy for energetic constraints relative to other life history traits and fitness components needs further attention13. Flight mills have been used before42, but we combined this performance measure with respirometry as the mill was constructed in a climatic chamber43. Several studies on the evolutionary ecology of insect flight implicitly assumed flight performance to be unidimensional, but different flight types correspond to different performances (e.g., speed, maneuverability, endurance27).…”

“…Flight performance of 111 females and 95 males (Sample sizes females/males per category: north-woodland-cool: 14/16; north-woodland-warm: 10/6; north-agri-cool: 14/13; north-agri-warm: 12/7; south-woodland-cool: 21/16; south-woodland-warm: 16/19; south-agri-cool: 11/14; south-agri-warm: 13/4) was measured in a flight mill with a lightweight carbon rod arm (length: 290 mm; diameter: 1 mm) threaded through a stainless steel pivot (magnets) providing near-frictionless movement43. The number of revolutions was recorded by a Hall Effect sensor (Labview v 8.6 software) and recalculated as the distance flown.…”