Living on the edge: Meoneura obscurella in the ‘Wieliczka’ Salt Mine (southern Poland) exhibits the first case of lecithotrophic ovoviviparity in the family Carnidae (Diptera)

Abstract

During the studies on the invertebrate fauna of the subterranean part of the “Wieliczka” Salt Mine in Wieliczka, Poland, the presence of many specimens of the dipteran species Meoneura obscurella (Fallén 1823) was observed. Organic remains and faeces related to the presence of mice (Mus musculus) were indicated as a potential food source for the insects. M. obscurella displays lecithotrophic viviparity (ovoviviparity), which has developed due to extremely harsh abiotic conditions and a lack of food. This is the first documented case of lecithotrophic viviparity within the fly family Carnidae. Based on the ability of this species to inhabit and reproduce in the conditions of the subterranean part of the “Wieliczka” Salt Mine, it is proposed to classify the species as a troglophile. The occurrence of Niptus hololeucus (Faldermann 1835), a species of beetle representing the family Ptinidae, was also confirmed in the subterranean part of the “Wieliczka” Salt Mine.