Fruit‐breeding drosophilids (Diptera) in the Neotropics: playing the field and specialising in generalism?

Abstract

1. Species of Drosophilidae are frequently used as model organisms, but their relationships with the environment, particularly in immature stages, remain poorly known. 2. This is the most comprehensive survey to date of fruit‐breeding drosophilids and their hosts in the Neotropics. Drosophilid host‐utilisation patterns were analysed as to geographic origin (native versus exotic) and level of specialisation. 3. The 180 species of plants recorded as drosophilid hosts are distributed across the main Angiosperm lineages and fleshy‐fruited orders; plant families that hosted the greatest number of drosophilid species were Arecaceae, Moraceae, and Myrtaceae. The 100 nominal drosophilid species recorded breeding in fruits belong to just over one‐third of Neotropical genera; most species (91) belong to Drosophila. Drosophilid species with the greatest resource breadth were Drosophila simulans, Drosophila nebulosa, and Zaprionus indianus. 4. Exotic drosophilids breed in more plant species than Neotropical drosophilids and use exotic hosts more frequently, possibly because they are generalists that have survived the trial of introduction and establishment in the Neotropics. Native drosophilids are more variable in resource breadth and sometimes adopt exotic hosts. 5. Amongst the 49 drosophilids with enough records for analysis (> 4), 48 were categorised as generalists. One possible explanation for such overwhelming generalism is the high diversity of Neotropical habitat or hosts. A second, non‐exclusive explanation, suggested by recent studies and empirically supported by the absence of host specialisation found in this study, is that drosophilids could be selective of the dominant yeasts and bacteria in host tissue, and not of the hosts themselves.

High niche partitioning promotes highly specialized, modular and non‐nested florivore–plant networks across spatial scales and reveals drivers of specialization

“…In contrast, generalist species like D. bromelioides that interacted with multiple plant species at the local community scale were also documented to interact with a high diversity of hosts in the Neotropics (49 distinct host species from 18 plant families), presenting consistent generalization. It is also important to note that while some FBD used few host plants for oviposition being, therefore, ‘specialists’ in a florivore–plant network, they may also use other resources such as cladodes, fungi and fruits (Carson , De Toni et al , Gottschalk et al , Valadão et al ). This was the case of only 16 out of the 104 species, namely, D. albirostris , D. ananassae , D. busckii , D. calloptera , D. cardini , D. cardinoides , D. cuaso , D. griseolineata , D. mediostriata , D. mediovittata , D. melanogaster , D. paulistorum , D. polymorpha , D. simulans , D. willistoni and Zaprionus indianus (Fig.…”

Natural enemies have inconsistent impacts on the coexistence of competing species

“…The six species span a range of body sizes (0.94 mg – 2.64 mg, mean wet mass of female adults) and phylogenetic divergences (SI 1, Table S1.1), have similar generation times, and can be distinguished visually (at least in the case of males). Drosophila are generalist feeders (Valadão et al, 2019) and in natural populations they experience high levels of parasitism, including from a suite of highly generalist natural enemies (Jeffs et al, 2020).…”

Exploring the role of host specialisation and oxidative stress in interspecific lifespan variation in subtropical tephritid flies

“…Alternatively, the absence of differences due to degree of specialisation might have been biased by the definition of specialist or generalist species itself, as here it relates to the number of host plants exploited by a species. For example, in drosophilids it was suggested that instead of selecting host plants, insects may rather select the microbiota inhabiting the host 48 , which would decrease the number of species categorised as specialists. The phenology of the plant species rather than the number of available hosts might explain some interspecific variance in lifespan.…”