Strepsiptera

Who's that peeking from between the abdominal plates of this female paper wasp? It's Xenos peckii, a member of the weirdest group of insects out there, the Strepsipterans.

Also called the twisted-wing parasites, these insects lead extraordinary lives.

It is a boiling hot August day. Yellowjackets, paper wasps, and mud daubers jostle for access to bright yellow flowers. In the middle of this mad dash, a paper wasp, weaving as she flies, overshoots a flower and crash-lands on a stem. Something is off. A closer look at her abdomen reveals female Strepsipterans poking their heads out from between the abdominal plates of their wasp host. This represents the farthest they will stray from their food source. These mature females will leave the adventuring to the next generation.

Since Strepsipterans feed through their skin, a newborn Strepsipteran must use its mother’s non-functional mouth to enter the world. After this auspicious start, the larvae either invade wasp larvae of the same colony to which their mother’s host belongs or hitch a ride on an uninfected wasp to a new nest. Once inside a wasp larva, the larvae wait until their wasp host has metamorphosized into an adult. This is where brothers must leave their sisters behind. Males metamorphosize inside their hosts, transforming into odd-looking winged creatures. Using their newfound wings and powerful eyes, they leave their wasps to see the world for a few short hours. The females remain in their larval form, poking their heads out of their adult host and releasing airborne chemicals called pheromones to attract males.

As any entomologist who has tried searching for this species can tell you, hopeful male suitors have their work cut out for them! Mature females are small bumps on the back half of a flying blur. When night falls and the host wasps have gathered on the nest to wait out the night, males follow scent trails and use their enlarged, unusually complex eyes to find a female before their time runs out. Even under stable lab conditions, males perish two to three hours after hatching (James et al., 2016)!

There is still so much to learn about these incredible insects. To find this species, practice looking at the abdomens of northern paper wasps for odd bulges.

Photo credit: Benjamin Burgunder

The Lifecycle of Xenos Peckii, Michael Habrar et al., 2014

References

Hrabar, Michael, Adela Danci, Sean Mccann, P.W. Schaefer, and Gerhard Gries. “New Findings on Life History Traits of Xenos Peckii (Strepsiptera: Xenidae).” The Canadian Entomologist 146 (February 13, 2014). https://doi.org/10.4039/tce.2013.85.

James, Marisano, Sri Pratima Nandamuri, Aaron Stahl, and Elke K. Buschbeck. “The Unusual Eyes of <em>Xenos Peckii</Em> (Strepsiptera: Xenidae) Have Green- and UV­-Sensitive Photoreceptors.” The Journal of Experimental Biology 219, no. 24 (December 15, 2016): 3866. https://doi.org/10.1242/jeb.148361.