Dasymutilla thetis, also known as the minute thistledown velvet ant, is a species of velvet ant known only from Arizona in North America. It was first described by as Sphaerophthalma thetis in 1886. Individuals are about 7 mm long. Females are "clothed entirely with ivory-white setae."
Ecology Dasymutilla thetis is part of a Müllerian mimicry complex among pale desert velvet ants, in which multiple unpalatable species share similar coloration to warn predators.Wilson, J. S., Sidwell, J. S., Forister, M. L., Williams, K. A., & Pitts, J. P. (2020). Thistledown velvet ants in the Desert Mimicry Ring and the evolution of white coloration: Müllerian mimicry, camouflage and thermal ecology. Biology Letters, 16(7), 20200242. https://doi.org/10.1098/rsbl.2020.0242 The pale (white) coloration of D. thetis may also serve a thermoregulatory function, helping individuals avoid overheating in hot desert habitats. The synonymy—Dasymutilla candida being a junior synonym of D. thetis—was confirmed using both molecular and morphological evidence in a taxonomic revision of southwestern Dasymutilla species.Pilgrim, E. M., Williams, K. A., & Pitts, J. P. (2008). Sex association and synonymy in southwestern U.S. species of Dasymutilla (Hymenoptera: Mutillidae). The Pan-Pacific Entomologist, 84(1), 57–68. https://doi.org/10.3956/2007-13.1 Like other velvet ants, D. thetis has a thick exoskeleton and delivers a painful sting, traits that are part of an effective defensive system against predators.Schmidt, J. O., Schmidt, L. S., & Schmidt, D. K. (2021). The paradox of the velvet-ant (Hymenoptera, Mutillidae). Journal of Hymenoptera Research, 84, 327–337. https://doi.org/10.3897/jhr.84.68795
Recent taxonomic reviews list D. thetis among the diurnal velvet ants found in the southwestern United States, particularly in California, Arizona, and Nevada.
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