Captain America without the shield: elytra loss and the evolution of alternative defence strategies in beetles

The formation of protective covers called elytra is considered to be a crucial morphological adaptation that has greatly supported the extraordinary radiation of beetles. However, in some beetle lineages, a reduction of elytra has occurred. Evolutionary consequences of this mysterious biological phenomenon have never been systematically discussed. In this study, a suggestive analogy to pop culture was used to illustrate a wide range of incredible defence strategies that can be found in several groups of beetles characterised by reduced elytra. This might include for instance: the hardening of the abdominal tergites, Batesian mimicry, aposematic coloration, chemical protection or defensive bioluminescence. It is not clear whether these new inventions have evolved as a direct response to the elytra loss, but it is very likely that the alternative defence strategies, common in brachelytrous beetles, might compensate for the loss of the primary protective structures. The use of suggestive analogies to pop culture icons, constitutes a promising tool for scientists to construct new theoretical templates, as well as to communicate and promote their recent findings, bridging the gap between researchers and the public.

Jakub Goczał