Many dung beetles utilize mammalian dung as a food source and build and relocate dung balls to lay eggs and shelter their larvae. Such behavior provides many ecosystem services such as nutrient cycling, secondary seed dispersal, soil excavation, and parasite and pest control.
Recent studies have shown that the use of genetic information from dung beetle guts (invertebrate-derived DNA or iDNA) allows for the detection of mammals in a given habitat without intensively surveying the area. However, these studies used live or freshly killed beetles instead of preserved specimens.
In a study published in Integrative Conservation, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) tested whether dung beetles collected by conventional pitfall traps, which preserve specimens with an alcohol-based solution, can be used to extract, sequence, and identify mammal DNA from their guts.
The researchers extracted iDNA from the guts of 18 dung beetles, comprising three species and three functional groups, collected from a seasonal tropical forest in Xishuangbanna, China. The composition of the detected species differed among the three functional groups but shared locally common wild boar and domestic cat. Paracoprids preserved the highest number of mammal species (seven out of eight total recorded), including rare species such as the Asian black bear, southern red muntjac, and the northern pig-tailed macaque.
They demonstrated that dung beetle specimens captured by conventionally used baited pitfall traps can preserve the DNA of mammal species in their guts. Conventionally used baited pitfall traps can capture diverse dung beetle species with various mammalian diets over an extended period in the field.
"Our proposed technique offers a viable alternative to traditional cafeteria experiments for understanding dung beetle-mammal interactions and can serve as a valuable complementary approach to current mammal survey techniques,”said Akihiro Nakamura of XTBG.
Akihiro Nakamura Ph.D Principal Investigator
Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
First Published: 08 November 2023