Carnivory in the larvae of Drosophila melanogaster and other Drosophila species

Abstract

Drosophila melanogaster is widely used as a model organism for biological investigations, and food is a major aspect of its ecology and evolutionary biology. Previous studies have shown that this insect can use fruits, yeasts and insect carcasses as its food sources. In this study, we demonstrate that this species is an omnivore, that its larvae can exploit not only fruits and yeast but also foods of animal origin (FAOs), and that larvae consume adult carcasses regularly. FAO-fed larvae develop into adulthood within a normal developmental time frame without the help of microbes. Yeast foods are better for Drosophila development than are foods of plant origin (FPOs) or FAO because in yeast foods, more eggs complete their life cycle, and the body size of emerged flies is much greater. Flies can use a mixture of yeast-FAO, which significantly boosts female fertility. Larvae digest FAOs externally. Larval D. virilis, D. hydei, and D. simulans are also omnivorous and demonstrate the same feeding habits as larval D. melanogaster. These findings prompt us to reconsider previous conclusions about the original adaptations of D. melanogaster and other Drosophila species and have direct implications for diet-related studies using Drosophila as a model organism.

Cannibalism and potential predation in larval drosophilids

“…In the assay of attraction to injured allospecifics, by contrast, all of the species were attracted to some of the allospecific SOA larvae as compared to random expectation. Although carnivory of D. auraria and D. triauraria has not been examined previously, Yang (2018) observed carnivorous behaviour in several drosophilids including D. melanogaster and D. simulans , supporting the current observation. Also, in Yang (2018), carnivory in drosophilids was tested using a variety of FAOs such as beef, clam, and roasted chicken, but no live food was tested.…”

“…Traditionally, yeasts associated with plant fermentation comprise the major food source of Drosophila melanogaster Meigen (Diptera: Drosophilidae), a widely used non‐carnivorous model insect (Cooper, 1960; Klaczko et al ., 1983). However, several studies have suggested that D. melanogaster is an omnivorous insect that can also consume a variety of foods of animal origins (FAOs), including carcasses of spiders or insects (Gregg et al ., 1990; Ahmad et al ., 2015; Yang, 2018). Among the FAOs, D. melanogaster larvae regularly consume wandering‐stage conspecifics under crowded laboratory conditions (Vijendravarma et al ., 2013).…”

“…The genus Drosophila contains over 1600 species with morphological, ecological, and behavioural diversity (O'Grady & DeSalle, 2018). Yang (2018) observed omnivorous feeding habits of Drosophila virilis Sturtevant (Diptera: Drosophilidae), Drosophila hydei Sturtevant (Diptera: Drosophilidae) and Drosophila simulans Sturtevant (Diptera: Drosophilidae). Adults of D. virilis and D. hydei can survive on FAOs, but only D. virilis and D. simulans were shown to complete their development on FAOs (Yang, 2018), suggesting that omnivorous feeding habit is not limited to D. melanogaster , but differs among species.…”

Sterols as dietary markers forDrosophila melanogaster

“…Sterol compositions of the three fly organs indicated that, independent of temperatures, flies were feeding on mixed diets containing comparable fractions of plant and yeast components. Interestingly, they also contained a sizable fraction of cholesterol suggesting that flies made occasional use of foods of mammalian origin [19]. Expectantly, the sterol compositon of beginning and end of August collections was similar.…”

On the expression of co-operative feeding behaviour in 3rd instar Drosophila melanogaster larvae!

“…will be more likely to engage in group foraging at higher densities in order to 72 access needed resources. However, as D. melanogaster larval cannibalism is 73 expressed in times of nutritional stress and can involve individuals consuming 74 other larvae (Vijendravarma et al 2013), adult carcasses (Yang 2018) and/or eggs 75 (Ahmad et al 2015; but see Narasimha et al 2019), at higher densities one 76…”