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Abstract Understanding the often antagonistic plant–herbivore interactions and how host defenses can influence herbivore dietary breadth is an area of ongoing study in ecology and evolutionary biology. Typically, host plants/fungi that produce highly noxious chemical defenses are only fed on by specialists. We know very little about generalist species that can feed and develop on a noxious host. One such example of generalists feeding on toxic host occurs in the mushroom‐feedingDrosophilafound in theimmigrans‐tripunctataradiation. Although these species are classified as generalists, their acceptable hosts include deadlyAmanitaspecies. In this study, we used behavioral assays to assess associations between one mushroom‐feeding species,Drosophila guttifera, and the deadlyAmanita phalloides. We conducted feeding assays to confirm the presence of cyclopeptide toxin tolerance. We then completed host preference assays in female flies and larvae and did not find a preference for toxic mushrooms in either. Finally, we assessed the effect of competition on oviposition preference. We found that the presence of a competitor's eggs on the preferred host was associated with the flies increasing the number of eggs laid on the toxic mushrooms. Our results highlight how access to a low competition host resource may help to maintain associations between a generalist species and a highly toxic host.
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Investigating the phylogenetic history of toxin tolerance in mushroom‐feeding Drosophila
Abstract Understanding how and when key novel adaptations evolved is a central goal of evolutionary biology. Within theimmigrans‐tripunctataradiation ofDrosophila, many mushroom‐feeding species are tolerant of host toxins, such as cyclopeptides, that are lethal to nearly all other eukaryotes. In this study, we used phylogenetic and functional approaches to investigate the evolution of cyclopeptide tolerance in theimmigrans‐tripunctataradiation ofDrosophila. First, we inferred the evolutionary relationships among 48 species in this radiation using 978 single copy orthologs. Our results resolved previous incongruities within species groups across the phylogeny. Second, we expanded on previous studies of toxin tolerance by assaying 16 of these species for tolerance to α‐amanitin and found that six of them could develop on diet with toxin. Finally, we asked how α‐amanitin tolerance might have evolved across theimmigrans‐tripunctataradiation, and inferred that toxin tolerance was ancestral in mushroom‐feedingDrosophilaand subsequently lost multiple times. Our findings expand our understanding of toxin tolerance across theimmigrans‐tripunctataradiation and emphasize the uniqueness of toxin tolerance in this adaptive radiation and the complexity of biochemical adaptations.
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- PAR ID:
- 10480727
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Ecology and Evolution
- Volume:
- 13
- Issue:
- 12
- ISSN:
- 2045-7758
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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