Proctodeal extrusion as a defensive behavioral response in blister beetles (Coleoptera: Meloidae)

Defensive mechanisms in blister beetles (Coleoptera: Meloidae) include a wide variety of behavioral responses, chemical defense, and conspicuous external colorations. Although some these have been previously described, proctodeal extrusion, defensive behavior involving the extrusion inner abdominal membranes from region which appear intensely red or orange colored when hemolymph is seen through them, has not reported to date. Here, we tested ability display response threat stimuli wild populations three beetle species inhabiting Central Spain: Berberomeloe majalis (Linnaeus, 1758), comunero Sánchez-Vialas, García-París, Ruiz & Recuero, 2020, Physomeloe corallifer (Germar, 1818). In addition, observed recorded various other behaviors such as immobility, antennal display, autohemorrhage (reflex bleeding), defecation, thanatosis (death feigning). The frequency at was differed among species, did stress intensity needed for probability particular threatening stimulus. Our findings indicate that, although might be widespread potential mechanism Meloidae, elicit it generalized across lineages. are endemic semi-arid Mediterranean region, adapted climate would developed strategies that limit hydric mirrors effect but without fluid loss.