Meeting Abstract
Mitochondrial function is key to health, performance, and fitness. Wild animals are exposed to changing environmental conditions which may result in stress to the individual. One such situation is reduced food availability. Reduced food availability limits an animal’s ability to support energetically expensive processes such as movement, reproduction, and somatic maintenance. While modest dietary restriction often has positive effects on health in mammals, invertebrates do not necessarily show the same response. Previous work on butterflies has demonstrated that dietary restriction reduces reproductive output and does not extend lifespan. Metabolic flight capacity however appears to be conserved under stressful conditions. Here, we examined the effects of starvation on mitochondrial respiration in a long-distance migrant, the North American monarch butterfly (Danaus plexippus). The monarch is an iconic species, yet its populations have been in sharp decline in recent years. We used reproductively active summer-generation monarchs that were subjected to 48 h of starvation. We found that starvation led to a lower respiratory control ratio, indicating reduced mitochondrial performance. The effect was mainly due to starved individuals having higher state 4 respiration, reflecting the increased uncoupling of the resting state when available ADP has been converted into ATP. The result suggests that a relatively short period of starvation can have detrimental effects of mitochondrial performance and possibly flight performance and fitness. Compromised mitochondrial function may act as a mechanistic link between reduced availability of nectar-providing flowers in agricultural landscapes and decreasing monarch populations across North America.
