Faculty of Natural and Agricultural Sciences
School of Biological Sciences
Department of Zoology and Entomology
Selected Highlights from Research Findings
Prof Clarke Scholtz and two members of his research group, Adrian Davis and Ute Kryger, published the definitive work on dung beetle evolution and conservation, Evolutionary biology and conservation of dung beetles, during the year. This was a synthesis of the authors’ combined total of about 80 years of research experience on dung beetles, and was based largely on the 200-odd papers they have jointly published on dung beetles, or those published with other leading international collaborators.
One of the exciting research projects that this research group are currently tackling is a study of the Cape high mountain stag beetles of the genus Colophon. These beetles are perceived to be very rare, but their presence on only the highest peaks of the Cape fold mountains under favourable climatic conditions for only the mid-summer months has contributed to this perception. As a result of their perceived rarity, they are highly prized by beetle collectors worldwide with single individuals changing hands for up to R100 000, which is, gram for gram, much more valuable than rhino horn or ivory. Conservation authorities consequently listed them on the listed species database of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which places them in similar conservation categories to elephant and rhino, and, consequently, all collection of and trade in these beetles is illegal. The UP researchers have special permits to undertake research on these beetles. This takes them, mostly on foot, to the highest peaks in the mountains with some of the most rugged and inhospitable, but spectacularly beautiful terrain imaginable. The results so far have been mixed, with limited success on some mountains and none on many others, but beetle researchers remain optimistic that the next time the results will be better.
Contact person: Prof CH Scholtz.
In 2009, Prof Nigel Bennett, together with Dr Marna Costanzo and Dr Heike Lutermann set out to investigate spatial learning and memory in two species of subterranean African mole rats that occupy extensive underground burrow systems. The Cape mole rat is a solitary species that generally has a simple burrow system with a geometric configuration considerably less complex than that of the Damaraland mole rat. The latter is a highly social species and may occur in colonies of up to 40 individuals.
In subterranean rodents, the complexity of the geometry of the burrow system varies both with the degree of sociality and – interestingly – with the sex of the animal. The researchers set out to determine if social species have superior abilities in spatial learning and memory compared to their solitary counterparts when navigating a complex maze. They further set out to investigate if there was a sex bias in spatial learning and memory.
Using an artificially designed maze system with a food reward at the end, the researchers demonstrated that there was no marked difference in learning and memory retention with respect to sex. In accordance with their hypothesis, marked differences between the species were apparent during both learning and memory trials, with the members of the social species showing superior performances. These findings suggest that individuals of social species may possess an enlarged hippocampus that may facilitate both learning and memory of the extensive labyrinth of tunnels that these animals call home.
Contact person: Prof NC Bennett.
In many species, females form strong social bonds with other females. In the case of female horses, such relationships have adaptive value: mares that form close social bonds with other mares have improved pregnancy, foal birth and foal survival rates, according to a study published in the Proceedings of the National Academy of Sciences by Prof Elissa Cameron. Their enhanced reproductive success appears to be linked primarily to mutual protection from harassment by stallions.
Studies in humans have shown that women with stronger friendships are healthier and have healthier babies. Similarly, previous studies on baboons have shown that strong social bonds enhance reproductive success. However, the value of close social bonds has previously only been shown between close relatives, but unlike most other mammal groups, mares form these tight bonds among unrelated females. In these horses, which live wild in the Kaimanawa mountains in the North Island of New Zealand, mares with the weakest social bonds had about half as many foals as those with stronger social bonds. Since these mares are not related, the value of friendship transcends the value of social relationships with relatives, suggesting that friendship is an evolutionary strategy.
Contact person: Prof EZ Cameron.
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