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Abstract Diet profoundly influences the composition of an animal’s microbiome, especially in holometabolous insects, offering a valuable model to explore the impact of diet on gut microbiome dynamics throughout metamorphosis. Here, we use monarch butterflies (Danaus plexippus), specialist herbivores that feed as larvae on many species of chemically well-defined milkweed plants (Asclepias sp.), to investigate the impacts of development and diet on the composition of the gut microbial community. While a few microbial taxa are conserved across life stages of monarchs, the microbiome appears to be highly dynamic throughout the life cycle. Microbial diversity gradually diminishes throughout the larval instars, ultimately reaching its lowest point during the pupal stage and then recovering again in the adult stage. The microbial composition then undergoes a substantial shift upon the transition from pupa to adult, with female adults having significantly different microbial communities than the eggs that they lay, indicating limited evidence for vertical transmission of gut microbiota. While diet did not significantly impact overall microbial composition, our results suggest that fourth instar larvae exhibit higher microbial diversity when consuming milkweed with high concentrations of toxic cardenolide phytochemicals. This study underscores how diet and developmental stage collectively shape the monarch’s gut microbiota.
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Impacts of larval host plant species on dispersal traits and free-flight energetics of adult butterflies
Abstract Animals derive resources from their diet and allocate them to organismal functions such as growth, maintenance, reproduction, and dispersal. How variation in diet quality can affect resource allocation to life-history traits, in particular those important to locomotion and dispersal, is poorly understood. We hypothesize that, particularly for specialist herbivore insects that are in co-evolutionary arms races with host plants, changes in host plant will impact performance. From their coevolutionary arms-race with plants, to a complex migratory life history, Monarch butterflies are among the most iconic insect species worldwide. Population declines initiated international conservation efforts involving the replanting of a variety of milkweed species. However, this practice was implemented with little regard for how diverse defensive chemistry of milkweeds experienced by monarch larvae may affect adult fitness traits. We report that adult flight muscle investment, flight energetics, and maintenance costs depend on the host plant species of larvae, and correlate with concentration of milkweed-derived cardenolides sequestered by adults. Our findings indicate host plant species can impact monarchs by affecting fuel requirements for flight.
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- Award ID(s):
- 1754996
- PAR ID:
- 10367252
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Communications Biology
- Volume:
- 5
- Issue:
- 1
- ISSN:
- 2399-3642
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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