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For Insects, Spiders & Their Kin
For the United States & Canada
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Order Strepsiptera - Twisted-winged Insects

Wasp - Xenos Wasp parasite - Xenos Strepsiptera - Triozocera - male Corioxenidae - male Mystery pool bug Sphex with Strepsipteran parasite - Paraxenos Red-marked Pachodynerus with Twisted-winged Parasite. - Xenos Strepsitera- unknown family - male
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Strepsiptera (Twisted-winged Insects)
Synonyms and other taxonomic changes
group that may be sister to beetles(1) and used to be included in beetles by some workers(2)
Explanation of Names
Greek streptos (στρεψισ) 'twisted' + pteron (πτερον) 'wing'(3)
84 spp. in 11 genera of 5 families in our area(4); worldwide, ~600 spp. in 43 genera of 10 families(5) arranged in 2 suborders, Mengenillidia (a single family, Mengenillidae of a dozen spp.) and Stylopidia (7 families)(6)(7)
Overview of our fauna (* –taxa not yet in the guide; classification per(5))
Order Strepsiptera
Family Corioxenidae
Family *Elenchidae
Family Stylopidae
0.5-4 mm(8)
Adult females are larviform/neotenic endoparasites; adult males are free-living, and their sole mission is to find and fertilize a female. They have reduced forewings and fan-shaped hind wings, branched antennae, and raspberry-like eyes, unique among living insects and somewhat similar to the eyes of trilobites.(7)
Key to families (adult males) in Kathirithamby & Taylor (2005)(4)
worldwide; suborder Stylopidia is cosmopolitan (2 families of 2 spp. each are restricted to the Neotropical and Oriental regions, respectively), Mengenillidia is an Old World group(7), the recently discovered monotypic Bahiaxenidae is a "living fossil" from Brazil(5)
obligate parasites of insects (hosts include members of 7 orders and 34 families)(7)
Life Cycle
Apart from the adult males, the only free-living stages are the viviparous 1st instar host-seeking larvae(7); the larvae hatch as free agents from eggs laid on flowers. When a suitable host visits the flower, the first stage larvae attach themselves to it and become parasitic.(8)
They were once thought to be related to the beetle families Meloidae and Ripiphoridae. Its taxonomic position among Insecta is still unresolved. Molecular data may settle the issue. (ToL)
Internet References
Fact sheets from Virginia Tech(9) and Discover Life