Exploring the potential systematic, morphological and functional value of the bullae in Ephemeroptera: Leptophlebiidae as an example.

ABDALA, VIRGINIA; DOMÍNGUEZ, EDUARDO

Aracruz

Congreso; XV International Conference on Ephemeroptera and XIX International Symposium on Plecoptera; 2018

Universidade Federal do Espirito Santo

Insects are the first living beings to fly, starting around 350 millionyears ago. The order Ephemeroptera is one of the most basal groups amonginsects. The extant species present a very short adult life span, mainlydedicated to fecundation and dispersal of eggs. The mating swarm and egg lyingrelies heavily on the flight characteristics, determined by the wing anatomy. Wingsare structures to fly and as such face a number of physical and physiologicalchallenges. The convex curvature along the anterior-posterior axis of the winggenerates a camber that must be carefully regulated. Camber regulation can beachieved by different strategies of flexural stiffness. One of the mostinteresting ways of flexural stiffness is provided by the bullae, which havebeen defined as short sections of flexible chitin in some longitudinal veins.Although the bullae have been frequently used as taxonomic characters, there isno study focused on their morphology, even though they probably play a mainrole in the flight of mayflies. In order to identify evolutionary tendencies ofthese structures of the wings within mayflies, we constructed a matrix with comparativeanatomy data of the bullae from whole mounts of the wings of 220 specimensbelonging to 70 ephemeral species, as well as scanning microscopy samples ofselected specimens. We also surveyed the number of bullae and theirdistribution in the wings of the different species of Neotropical Leptophlebidae.We optimized these characters onto the last published phylogeny of SouthAmerican Leptophlebidae.