Advisor: Harald Krenn

Master's Defensio

Monday, January 20th, 2025, 13:45 CET
SR 1.2, UBB
Djerassiplatz 1, 1030 Vienna

Abstract

Monkey beetles are South African beetles belonging to the tribe Hopliini (Scarabaeidae), a megadiverse group of about 1400 species worldwide. These beetles visit flowers, and many species are important pollinators of endemic plant species in the Great Cape Floristic Region of South Africa. They often show sexual dimorphism and many Hopliini have evolved different diets consisting of floral tissue, pollen or nectar. The digestive tract morphology of these flower-visiting beetles is understudied although mouthpart adaptations of the members of these feeding guilds raise the question if the morphology of the alimentary tract of Hopliini reflects the feeding preference. To answer this question the morphology of the gut was examined in eleven species of South African monkey beetles using micro-CT imaging. The results of this present study of the alimentary tract revealed that compartmentalization of the digestive tract is similar to the gross morphology of other coleopteran species. The results showed that food preference of studied hopliine beetles had probably no effect on the total length of the digestive tract, while the foregut was significantly longer in pollen and nectar feeders compared to floral tissue feeders. In addition, female beetles exhibited longer midguts and larger foregut volumes in relation to body size compared to male beetles. This could be due to the more stationary lifestyle and additional energy needs of female beetles. This morphometric approach, which was applied for the first time to study the gut of a flower-visiting insect, can be used for future comparative anatomical studies.