Researchers have identified two new endemic Hawaiʻi spiders—the Argyrodes ilipoepoe on Kauaʻi and Argyrodes laha on Oʻahu, Molokaʻi and Maui. The third Hawaiian member of that genus, A. hawaiiensis, was found previously on the Big Island.
All three species are kleptoparasitic, dining on prey caught in webs built by other spiders. Their restaurant of choice: the sheet web of the large nocturnal Orsonwelles spider, says University of Hawaiʻi at Mānoa zoologist Malia Rivera.
As many as 60 have been found on the upper scaffolding of a web while the host Orsonwelles hangs beneath.
Their dependence on the endemic host spider for meals may explain why the genus has not diversified like the 10 free living endemic Ariamnes spider species earlier identified by Rivera and former UH colleague Rosemary Gillespie.
Characterized by their small rounded abdomens and variably long fangs, the tiny Argyrodes spiders were identified using dissecting and scanning electron microscopes and camera lucida.
The findings were reported in the University of Hawaiʻi Press journal Pacific Science. Read the abstract.