New dung beetle species reveal insights into ecological relationships
In a surprising twist to what might seem like an ordinary school run, Christian Deschodt, a doctoral student at the University of Pretoria (UP), has uncovered two new species of dung beetles over the past two decades of exploring Southern Africa’s diverse landscape. However, the path to this momentous discovery illuminated a unique connection between parental duties and scientific exploration.
Deschodt, who has contributed to the discovery and description of more than 50 new dung beetle species, recently made headlines with the announcement of a newly identified species named Hathoronthophagus spinosa.
This remarkable species was documented in Zootaxa, a journal renowned for featuring groundbreaking species discoveries. This exciting find came about during a routine 1.5-km walk to fetch his children from a primary school located near Hartbeespoort, a mere 30 km from his university.
"After a morning of research work, I like to stretch my legs by taking a walk to fetch my two children from primary school," Deschodt said, reflecting on the seemingly mundane but fortuitous occurrence.
On a January day in 2023, following a rain shower, Deschodt's walk led him to stumble upon a tiny chocolate-brown dung beetle, no larger than 5 mm. Intrigued by his discovery, he collected the specimen while carefully avoiding the common pugnacious ants surrounding it.
What began as a simple stroll evolved into a pivotal moment in entomological research. After examining the specimen under a microscope at home, Deschodt realised he had encountered a female dung beetle of an entirely new species and promptly named it Hathoronthophagus, inspired by the ancient Egyptian deity associated with joy and maternal care.
“I was reminded of Hathor, as she was often depicted wearing a headdress adorned with cow horns, similar to the longish horns of Hathoronthophagus spinosa,” he explained.
Despite extensive efforts to find more specimens, including bait lures with cattle dung throughout Hartbeespoort, Deschodt has so far only encountered that singular individual.
This leads him to suspect that Hathoronthophagus spinosa might inhabit ant nests, possibly offering a mutualistic relationship with its surrounding ecosystem. “I hope that news about this find will prompt experts working in Southern Africa to further investigate the relatively unknown relationship between ants and dung beetles,” he expressed, underscoring the need for further research into this intriguing area.
South Africa is home to approximately 500 species of dung beetles, with over 700 species identified across Southern Africa, including Botswana, Namibia, southern Mozambique, and Zimbabwe. The rich diversity is largely attributed to South Africa's varied geography and numerous vegetation types. Deschodt notes that some beetle species are highly selective about dung types, with certain species residing solely on elephant or rhinoceros dung. For his PhD research, he is currently studying a flightless genus native to Namibia and western South Africa, which exclusively consumes dung pellets from rock hyraxes, commonly known as dassies.
Contrary to common misconceptions, not all dung beetles adhere strictly to faeces; some species are scavengers, indulging in carrion or even mushrooms. In a separate new paper published in Zootaxa, Deschodt detailed another new species named Onthophagus pragtig, which seemingly consumes the innards of dead millipedes. This unusual feeding behaviour represents a remarkable deviation from typical dung beetle habits.
“These beetles can enter a millipede's carcass through any available breach, consuming the soft tissues and forming small balls to save for later. The way Onthophagus pragtig forms a ball with viscera and buries it beneath the millipede carcass is a unique behaviour that merits further study,” Deschodt explained. He noted the intriguing composition of millipedes, which possess substances harmful to most animals including hydrogen cyanide, highlighting the complex adaptations found within these beetle species.
With species featuring an array of colours from black to metallic shades, the coppery-red vibrance of Onthophagus pragtig stands out. Deschodt explained the choice of name, calling it "pragtig," which translates to "splendid" in Afrikaans. First specimens of Onthophagus pragtig were collected in Limpopo and the Northern Cape, enriching UP's collections.
With comprehensive exploration of carrion and millipede carcasses necessary to uncover hidden species like Onthophagus pragtig, Deschodt hopes this newfound interest will pave the way for further discoveries.
“These beetles are not as easily attracted to faeces bait, so studying them presents its unique challenges,” he noted, underscoring the need for innovative approaches within entomological research.