Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Master → Afrique du Sud → 2021 → Understanding the role of specialized mouthparts in the selective feeding of dung beetles (coleoptera : scarabaeinae)

University of the Witwatersrand (2021)

Understanding the role of specialized mouthparts in the selective feeding of dung beetles (coleoptera : scarabaeinae)

Mathikge, Nthabiseng Gladys

Titre : Understanding the role of specialized mouthparts in the selective feeding of dung beetles (coleoptera : scarabaeinae)

Auteur : Mathikge, Nthabiseng Gladys

Université de soutenance : University of the Witwatersrand

Grade : Master of Science (MS) 2021

Résumé partiel
The use of a complex food substance such as herbivore dung, by dung beetles has promoted the evolution of an adaptive feeding strategy known as particle feeding. Selection of fine particulate matter elevates the food nutrient quality by up to five-fold. However, it is not known how dung beetles achieve this. An ephemeral food source such as dung is not always available, thus several dung beetle genera have resorted to exploring alternative diets such as dead plant material and mushrooms, dry dung pellets and carrion to name a few. How they use similar mouthparts to process this food is not known. Dung beetles possess highly specialized mouthparts, but how these operate is still not fully understood. Several hypotheses attempting to explain the mode of action of these mouthparts have been put forward but only one has been consistent with several experimental findings. This hypothesis suggests that dung beetles increase the nutrient quality of dung using their mouthparts as a filtering apparatus that concentrates minute and nutritious dung particles while eliminating excess water and intractable plant fragments with no nutritional value. To gain more insight on this topic, this study investigated the morphology of various internal components of dung beetle mouthparts to understand their respective roles in particle feeding. Microscopy and geometric morphometric analysis were used to examine and compare the mouthparts of 12 dung beetle species belonging to four feeding groups (generalist, wet dung, carrion and dry diet feeders). The qualitative microscopy analysis revealed that dry diet feeders possess grinding and cutting structures, which are reduced or absent in the generalist, carrion and wet dung feeders.

Présentation

Version intégrale (6,7 Mb)

Page publiée le 13 janvier 2023