Ulysséa, M.A., Farder-Gomes, C.F. & Prado, L.P.

Biological notes, nest architecture, and morphology of the remarkable ant Hylomyrma primavesi Ulysséa, 2021 (Hymenoptera: Formicidae: Myrmicinae)

Natural history discoveries have contributed to broad applications in the fields of taxonomy, ecology, evolution, and conservation of the species. Knowledge on the biology of species of the Neotropical ant genus Hylomyrma Forel, 1912 remains incipient despite the substantial data reported during its last taxonomic revision. Here, based on fieldwork carried out in an area of Campo Rupestre (Rupestrian Field) in Minas Gerais, Brazil, we present the first biological data of the recently described species Hylomyrma primavesi Ulysséa, 2021, including the descriptions of the ergatoid queen, male, larva, female reproductive tract, nest architecture, and feeding behavior. Hylomyrma primavesi forage solitarily and prefer very small insects (Collembola and larvae, pupae, and imagos of Diptera and Coleoptera). Its nests are found in sandy soil and are not deep. One straight tunnel connects the tube entrance to a final chamber. The colonies comprised approximately 7 - 65 workers and intercaste specimens and one ergatoid queen per colony. The structure of the female reproductive tract of H. primavesi is similar to that in other Myrmicinae. Workers and intercaste specimens have one pair of ovarioles and lack the spermatheca, while the ergatoid queen has three pairs of ovarioles and spermatheca. Most remarkably, it is the only Hylomyrma species that has only ergatoid queens. Lastly, we comment on the evolution of new castes in Hylomyrma from the perspective of the hourglass model and the standard model. The findings reported here fill gaps in the understanding of the natural history of cryptobiotic species and shed light on the caste development and evolution in Hylomyrma.

Open access, licensed under CC BY 4.0. © 2024 The Author(s).

Ergatoid queen, male, larva, Pogonomyrmecini, ovary, spermatheca, taxonomy.