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Order Strepsiptera - Twisted-winged Insects

 Stylopized Sphecid - Eupathocera auripedis Wasp - Xenos peckii Twisted-winged Insect (Xenos sp.) parasites - Xenos peckii 3rd time's a charm - Halictoxenos - male - female 3rd time's a charm - Halictoxenos Xenos - Xenos peckii Paraxenos - Eupathocera westwoodi Leionotoxenos tigridis
Classification
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Strepsiptera (Twisted-winged Insects)
Synonyms and other taxonomic changes
probably sister to beetles(1) and used to be included in beetles by some workers(2)
Explanation of Names
Strepsiptera Kirby, 1813
'twisted wing'
Numbers
84 spp. in 11 genera of 5 families in our area(3); worldwide, ~600 spp. in 43 genera of 10 families(4) arranged in 2 suborders, Mengenillidia (3 extant families) and Stylopidia (7 families)(5)(6)
Overview of our fauna (* –taxa not yet in the guide; classification per(4))
Order Strepsiptera
Family Corioxenidae
Family *Elenchidae
Family Stylopidae
Size
0.5-4 mm(7)
Identification
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.(6)
Key to families (adult males) in (3)
Range
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(6), the recently discovered monotypic Bahiaxenidae is a "living fossil" from Brazil(4)
Food
obligate parasites of insects (hosts include members of 7 orders and 34 families)(6)
Life Cycle
Apart from the adult males, the only free-living stages are the viviparous 1st instar host-seeking larvae(6); the larvae hatch as free agents from eggs laid on flowers. When a suitable host visits the flower, the larva attach itself to it and become parasitic.(7)
Print References
Benda D, Pohl H, Nakase Y, Beutel R, Straka J (2022) A generic classification of Xenidae (Strepsiptera) based on the morphology of the female cephalothorax and male cephalotheca with a preliminary checklist of species. ZooKeys 1093: 1-134. https://doi.org/10.3897/zookeys.1093.72339
Internet References
Fact sheets from Virginia Tech(8) and Discover Life