Dr Nkitseng Modise’s Entomology PhD revealed how, in the bee-and butterfly-scarce heights of South Africa’s Drakensberg mountains, Crassula peploides relies on short-tongued flies for pollination – luring them with nectar and a pungent scent similar to vomit or sweaty feet.
After completing his undergraduate and master’s studies at the University of Johannesburg, Modise chose UKZN for his PhD because of the reputation of the Pollination Ecology laboratory headed by Professor Steve Johnson. Having branched into Entomology from Zoology during his undergraduate studies inspired by his lecturers, Dr Lolo Mokae and Professor Bettine van Vuuren, he was intrigued by the prospect of studying insects and their interaction with the environment on a molecular level.
For his PhD research, he focused on fly pollination of several flowers at high elevations, specifically in the Drakensberg mountains in KwaZulu-Natal and the Eastern Cape. He investigated whether some plants were pollinated by short-tongued flies in these high-elevation regions by analysing both the floral and pollinator traits as well as the diversity of flies caught on the studied plants.
He uncovered the important role that short-tongued flies play as pollinators in high-elevation regions where common pollinators are in low numbers. He also aimed to shift the negative connotation of flies as unimportant and annoying to demonstrate to the public that flies, much like bees, are an integral part of the environment.
Modise documented the first report of pollinators of the studied Crassula species, all of which emit smells unpleasant to humans, with acidic compounds in the scent also found in vomit and sweat. This suggests that these flowers use this scent to attract short-tongued flies in combination with other floral traits. Usually, pollination systems involving short-tongued flies as pollinators mimic a substrate such as a dead animal or insect egg-laying sites and do not provide a nectar reward to the pollinators, but in Modise’s research, pollinating flies were rewarded with a small quantity of nectar. He also found that the studied plants interact flexibly with a wide variety of short-tongued flies and yet are not visited by all the available short-tongued flies.
His research resulted in a publication in the South African Journal of Botany, with another to be published in the Botanical Journal of the Linnean Society.
Moving from molecular biology to pollination ecology at UKZN was a challenge, but Modise joined honours classes facilitated by Johnson to boost his knowledge of the basics of pollination ecology and found assistance from his supervisors.
Originally from the rural Bollantlokwe in the North West Province, attending school there and in Johannesburg, Modise found UKZN to be a warm and inclusive environment and enjoyed interacting with students at all levels as well as staff members who he found supportive and encouraging.
He joined the soccer team of the former School of Life Sciences on arrival, and formed friendships with colleagues at UKZN, also finding time to visit family and friends in Johannesburg.
Developing his career in the sciences, Modise is now a Postdoctoral Research Fellow at the South African National Biodiversity Institute in Pretoria, focusing on molecular epidemiology and host-parasite-environment interactions, and hopes to venture into academia to integrate his research and teaching.
Modise thanked God for making his studies possible, and his mother, Ms Seipati Winnie Modise, and wider family for their support of his education and for realising his dreams. He thanked Mokae and van Vuuren for their mentorship, encouragement and support, and his supervisors, Professor Timotheus van der Niet, Dr Ruth Cozien, Dr Kurt Jordaens and Dr Adam Shuttleworth for the opportunity and encouragement to complete this research, and the teamwork that made it possible. He acknowledged the Diversity of Pollinating Diptera in South African Biodiversity Hotspots project financed by the Directorate-General Development Cooperation and Humanitarian Aid through an agreement with the Africa Museum in Belgium for funding his PhD. He also thanked his friends, particularly Mr Anwar Junior Molwele, for their camaraderie.
Words: Christine Cuénod
Photograph: Sethu Dlamini