Description of first instar larvae of the subgenus Praocis Eschscholtz, 1829 (Coleoptera: Tenebrionidae), endemic element from the coastal desert of Chile

PIZARRO-ARAYA, J., D.A. MARÍN, N.I. CONTRERAS, F.M. ALFARO Y G.E. FLORES

Simposio; IV International Tenebrionoidea Symposium; 2015

The subgenus PraocisEschscholtz, 1829 (Pimeliinae: Praociini), is an endemic group of north-centralChileencompassing 18 species distributed mostly across the Chilean desert andcoastal steppe. In this work we describe the morphology and structure of the firstinstar larvae of Praocis (Praocis) spinolai Gay & Solier, 1840, Praocis (Praocis) subaenea Erichson, 1834, Praocis (Praocis) curta Solier,1840, and Praocis (Praocis) sulcata Eschscholtz, 1829 (Coleoptera: Tenebrionidae), all of themendemic elements of the transitional coastal desert of Chile. To obtain larvae,male and female individuals were collected in the fields and maintained inmating boxes until oviposture and hatching. The structure and externalmorphological features of the larvae were analyzed via scanning electronmicroscopy (SEM). The results show that first instar larvae have morphologicaladaptations to edaphic environments, such as prothoracic legs for digging,strongly-sclerotized cephalic capsule with large number of sensilla, andwell-developed pygopodium. We analyzed the importance of certain morphologicalfeatures as specific diagnostic criteria and determined that the differences inthe frontal sensilla, clipeum shape, anterior labrum margin, and pygopodiumshape between the species is of taxonomic and, probably, phylogenetic value.