R. Mizuno, K. Eguchi, R. Satria, A.V. Dang, V.T. Bui, L.T.H. Phung, F. Ito
The ant subfamily Dorylinae consists of the so-called true army ants and their relatives. The latter (= non-army ant doryline genera) was formally known as cerapachyine ants. Among this non-army ant doryline genera, the genus Yunodorylus is part of a clade likely sister related to the Eastern Hemisphere army ants and has remarkable queen morphology (subdichthadiigyne). They are enigmatic ants, however, because of their limited distribution and rareness. Therefore, their behavior and biology have never been reported. In this study, we collected two colony fragments of Yunodorylus eguchii, (Borowiec in Zootaxa 2069(1):43–58, 2009) in Vietnam, and their behavior was observed under laboratory conditions. Both colonies were monogynous and included 300 and 450 workers, but their whole colony size was estimated to be much larger. The caste dimorphism was conspicuous; the head width of queens was notably larger than that of workers. The head width of workers was negatively allometric to their head length; the larger workers have a relatively broader head. The colonies showed phasic reproduction under laboratory-rearing conditions. The duration of an entire reproductive cycle was 56 and 63 days. The queens' abdomen became physogastric during the egg-laying phase. Colony emigration was frequently observed but never occurred while the queen was fully physogastric. The colonies predate on various prey arthropods offered in the laboratory, including ant brood, termites, mealworms, and killed cockroaches. Our results reveal unique biological traits in Yunodorylus that shed light on the evolution of the army ant adaptive syndrome. © 2023, International Union for the Study of Social Insects (IUSSI).
Faculty of Agriculture, Kagawa University, Miki, Ikenobe, 761-0795, Japan; Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Hachioji, 192-0397, Japan; Department of Biology, Faculty of Mathematics and Natural Sciences, Universitas Negeri Padang, Padang, Indonesia; Department of Soil Ecology, Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology, 18, Hoang Quoc Viet Rd., Cau Giay District, Hanoi, Viet Nam; Vietnam National Museum of Nature, 18 Hoang Quoc Viet Rd, Cau Giay District, Hanoi, Viet Nam
