Effects of flight and food stress on energetics, reproduction, and lifespan in the butterfly Melitaea cinxia

Abstract

Environmental change can have drastic effects on natural populations. To successfully predict such effects, we need to understand how species that follow different life-history strategies respond to stressful conditions. Here I focus on two stressors, increased flight and dietary restriction, and their effects on bioenergetics and life-history. Using the Glanville fritillary butterfly (Melitaea cinxia), I subjected mated females to three treatments: (1) control conditions, (2) repeated forced flight with unlimited food, and (3) repeated forced flight coupled with food restriction. Interestingly, flight increased fecundity: females in both flight treatments initiated oviposition earlier, laid more egg clutches, and had higher total fecundity than control females. However, food-restriction by 50% reduced clutch size and resulted in an approximately 25% decrease in total fecundity compared to flown females with unlimited food. There were no differences in egg wet mass, water content or hatching success. Flown females with unlimited food appeared to exhibit a trade-off between reproduction and lifespan: they had higher mass-independent resting metabolic rate and shorter lifespan than females in the other treatments. Mass-independent flight metabolic rate, reflecting flight capacity, did not differ among the treatments. There were no differences in the rate of metabolic senescence across the treatments. The current findings suggest a mechanistic link between flight and reproduction, potentially mediated by juvenile hormone signalling. It appears that this wing-monomorphic butterfly does not show an oogenesis-flight trade-off often found in wing-dimorphic insects. Nevertheless, nectar-feeding is needed for achieving maximum reproductive output, suggesting that diminishing nectar resources may negatively impact natural populations.

Effects of environment and genotype on dispersal differ across departure, transfer and settlement in a butterfly metapopulation

“…Nests of dispersers versus residents (electronic supplementary material, table S5) and long-distance and short-distance dispersers ( figure 3 ; electronic supplementary material, table S3) were equally likely to survive overwinter, suggesting that there is no direct cost to dispersal during the transfer phase among those that successfully dispersed [ 22 ]. This is consistent with previous experimental work that failed to find trade-offs between flight and reproduction [ 78 , 79 ] and even reported positive relationships between mobility and egg production [ 80 ]. Instead, some costs are apparently paid after settlement through direct negative effects of settling in poor-quality patches [ 81 ].…”

“…Interestingly, the amount of grazing in the disperser's natal patch had much stronger effects on the survival of nests ( figure 3 ; electronic supplementary material, table S3), suggesting that mothers from low-quality patches might decrease investment in reproduction at the cost of maintaining investment in flight. Effects of food stress on quality and quantity of offspring after flight have been found in other butterflies [ 82 ], including M. cinxia ; Niitepõld [ 79 ] found no difference in flight metabolic rate in butterflies exposed to unlimited versus restricted food, but food-restricted females had significantly lower clutch size after flight.…”

Host plant diet affects growth and induces altered gene expression and microbiome composition in the wood white (Leptidea sinapis) butterfly

“…However, there is ample evidence that body size is positively associated with female fecundity and negatively associated with stress in several butterfly species (Carnicer et al, 2019;Johnson et al, 2014;Niitepõld, 2019), including Leptidea sp. (Friberg & Wiklund, 2009;Lukhtanov et al, 2018).…”

Developmental temperature predicts body size, flight, and pollen load in a widespread butterfly

“…We first use laboratory experiments to examine the effects of warming on body size and flight in the widespread butterfly species Pieris rapae (Lepidoptera, Pieridae). We focus on these traits because of their clear links to fecundity, mating success, resource acquisition, dispersal, and plant‐insect interactions (Almbro & Kullberg, 2012; Bauerfeind & Fischer, 2008; Duplouy et al, 2018; Larranaga et al, 2019; Niitepõld, 2019). Second, we use the results from the experiment to predict how butterfly wing size should affect pollen accumulation and diversity in P. rapae , and we test these predictions using a correlational study on wild‐caught P. rapae .…”