Possible indicators of the type of feeding habits: analysis of the mouthparts of five Dichotomius species (Coleoptera: Scarabaeidae) from Argentina

GIMENEZ GOMEZ, VICTORIA C. ; TONELLI, MATTIA; VERDÚ, JOSÉ R.; MEDINA, CLAUDIA A.; M. VICTORIA SÁNCHEZ; GUSTAVO ZURITA

COLEOPTERISTS BULLETIN

COLEOPTERISTS SOC

Año: 2023

0010-065X

Dung beetles exhibit a wide range of trophic preferences, including soft and hard esources. The study of mouthparts associated with these resources is extensive, and mouthparts of these insects have generally been described as membranous, hairy, and poorly adapted to cutting hard food. In this study, we compare the mouthparts (epipharynx, labium, and hypopharynx) of five species of Dichotomius Hope from Argentina that show differences in their trophic preferencess to evaluate if these structures also differ according to their feeding habit. We found epipharyngeal, hypopharyngeal teeth, and more sclerotized structures in species that consume hard resources (Dichotomius carbonarius Mannerheim) and the absence or reduction of them in species that consume soft resources (Dichotomiussericeus Harold, Dichotomius nisus Olivier, Dichotomius mormon Ljungh, and Dichotomius depressicollis Harold). On the other hand, the latter species have hairier and softer mouth structures associated with these soft resources. According to these results, a detailed study of the macrostructures of mouthparts could indicate a priori the resource state consumed by a dung beetle species: the presence or absence of teeth and sclerotized structures would be associated with hard or soft food as the main resource, despite the occasional use of other resources in the field.