Drosophila melanogaster wounding in the wild

Wounding occurs across multicellular organisms. Wounds can affect host
mobility and reproduction, with ecological consequences for competitive
interactions and predator-prey dynamics. Wounds are also entry points for
pathogens. An immune response is activated upon injury, resulting in the
deposition of the brown-black pigment melanin in insects. Despite the
abundance of immunity studies in the lab and the potential ecological and
evolutionary implications of wounding, the prevalence of wounding in
wild-collected insects is rarely systematically explored. We investigated
the prevalence and potential causes of wounds in wild-collected
Drosophilidae flies. We found that 31% of Drosophila melanogaster were
wounded or damaged. The abdomen was the most frequently wounded body part,
and females were more likely to have melanised patches on the ventral
abdomen, compared to males. Encapsulated parasitoid egg frequency was
approximately ten percent, and just under one percent of Drosophilidae
species had attached mites, which also caused wounds. Wounding is
prevalent in D. melanogaster, likely exerting selection pressure on host
immunity for two reasons: on a rapid and efficient wound repair, and on
responding efficiently to opportunistic infections. Wounding is thus
expected to be an important driver of immune system evolution and to
affect individual fitness and population dynamics.