ARS | Publication request: What's in a frog stomach? Solving a 150 year old mystery (Diptera: Calliphoridae)

Submitted to: Systematic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 30, 2007
Publication Date: June 19, 2008
Citation: Pape, T., Szpila, K., Thompson, F.C. 2008. What's in a frog stomach? Solving a 150 year old mystery (Diptera: Calliphoridae). Systematic Entomology. 33:548-551.

Interpretive Summary: Calliphorid, or blow fly adults lay eggs on decaying or living tissues of animals or man, and maggots feed on the tissues, for example the screwworm fly that attacks cattle. This paper establishes the identity and name of blow fly maggots found in edible frogs from Germany. The maggot is a parasitoid of earthworms, and the frogs ate the earthworms. This case illustrates an expanded range of possible contaminants in food and the information will be useful to regulatory agencies, as well as biologists and parasitologists.

Technical Abstract: The taxon Acanthosoma chrysalis Mayer, 1844, described from Germany on a number of alleged parasites encysted in the peritoneal wall of the stomach of edible frogs, is revised and shown to be first instar larvae of blow flies (Calliphoridae). Based on the shape of mouthhooks and abdominal cuticular spines, A. chrysalis is argued to be a junior synonym of Onesia floralis Robineau-Desvoidy, 1830, SYN.N. This species is an obligate parasitoid of earthworms, and it is hypothesized that first instar larvae have entered the frogs through infected earthworms.