Dasymutilla

Dasymutilla is a wasp genus belonging to the family Mutillidae. Their larvae are external parasites to various types of ground-nesting Hymenoptera. Members of this genus are highly variable in sting intensity, ranging from a 1 (D. thetis) to a 3 (D. klugii) in the Schmidt sting pain index.^[1]

Dasymutilla
Dasymutilla aureola, Santa Clara County, California, 2018
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Mutillidae
Tribe:	Dasymutillini
Genus:	Dasymutilla Ashmead, 1899
Species
~200 species; see text

Selected species

• D. alesia
• D. archboldi
• D. arenivaga
• D. asopus
• D. aureola
• D. bioculata
• D. californica
• D. calorata
• D. chattahoochei
• D. chiron
• D. chisos
• D. coccineohirta
• D. creon
• D. creusa
• D. dilucida
• D. eminentia
• D. foxi
• D. gibbosa
• D. gloriosa (thistledown velvet ant)
• D. gorgon
• D. heliophila
• D. klugii
• D. lepeletierii
• D. magnifica
• D. meracula
• D. monticola
• D. mutata
• D. munifica
• D. nigricauda
• D. nigripes
• D. nitidula
• D. nocturna
• D. nogalensis
• D. occidentalis (cow killer)
• D. pyrrhus
• D. quadriguttata
• D. sackenii
• D. santanas
• D. scaevola
• D. sicheliana
• D. thetis
• D. vesta
• D. vestita

Female D. gloriosa

Defenses

Certain members of this genus are known for their painful and venomous sting. On the Starr sting pain scale, at least one velvet ant species (Dasymutilla klugii) outscored 58 species of wasps and bees in the painfulness of its sting, falling short of only the bullet ant (Paraponera clavata), the warrior wasp (Synoeca septentrionalis), and the tarantula hawk (genus Pepsis).^[2]

Many species within this genus exhibit Müllerian mimicry. There is an eastern mimicry ring, which includes D. occidentalis and D. vesta, and there is the western mimicry ring, which includes many other species. The effect is to warn off predators by shared aposematic coloration without requiring inexperienced predators to taste and be stung by members of each species separately.^[3][4]

Aside from their aposematic coloration, they can produce a loud squeaking noise which also warns potential predators. Their exoskeleton is remarkably strong; experiments concluded that 11 times more force was needed to crush the exoskeleton of a female velvet ant than that of a honey bee.^[5]

References

1. Schmidt, Justin (2016). The Sting of the Wild. Baltimore, Maryland: Johns Hopkins University Press. ISBN 978-1-4214-1929-9.
2. Starr, Christopher K. (1985). "A simple pain scale for field comparison of Hymenopteran stings" (PDF). Journal of Entomological Science. 20 (2): 225–32. doi:10.18474/0749-8004-20.2.225.
3. Wilson, Joseph S.; Williams, Kevin A.; Forister, Matthew L.; von Dohlen, Carol D.; Pitts, James P. (11 December 2012). "Repeated evolution in overlapping mimicry rings among North American velvet ants". Nature Communications. 3 (1): 1272. Bibcode:2012NatCo...3E1272W. doi:10.1038/ncomms2275. PMID 23232402.
4. Wilson, Joseph S.; Jahner, Joshua P.; Forister, Matthew L.; Sheehan, Erica S.; Williams, Kevin A.; Pitts, James P. (August 2015). "North American velvet ants form one of the world's largest known Müllerian mimicry complexes". Current Biology. 25 (16): R704–R706. doi:10.1016/j.cub.2015.06.053. PMID 26294178.
5. Gall, Brian G.; Spivey, Kari L.; Chapman, Trevor L.; Delph, Robert J.; Brodie, Edmund D.; Wilson, Joseph S. (2018). "The indestructible insect: Velvet ants from across the United States avoid predation by representatives from all major tetrapod clades". Ecology and Evolution. 8 (11): 5852–62. doi:10.1002/ece3.4123. PMC 6010712. PMID 29938098.

• Evans, Arthur V. (2007). Field Guide to Insects and Spiders of North America. Sterling Publishing Co. p. 371. ISBN 9781402741531.
• "List of Dasymutilla". Retrieved 2008-09-13.
• "Genus Dasymutilla". Retrieved 2008-09-13.
• "San Diego Natural History Museum Dasymutilla sp". Archived from the original on 2002-02-25. Retrieved 2008-09-13.