Life history and captive rearing of the Wekiu bug (Nysius wekiuicola, Lygaeidae), an alpine carnivore endemic to the Mauna Kea volcano of Hawaii

The hemipteran family Lygaeidae contains species that are overwhelmingly plant and seed feeders. The Wekiu bug, Nysius wekiuicola, a candidate endangered species endemic to the summit of the 4,205 m volcano, Mauna Kea, and the closely related A’A bug, Nysius aa, are the only obligate carnivore scavengers of the family. Despite its unique diet, remarkable ecology, and high profile due to conservation concerns, there is still little known about the Wekiu bug. We present the first detailed observations and descriptions of the Wekiu bug, including a complete life history. The Wekiu bug lays eggs singly or in small loose clutches, matures after five nymphal instars, and can survive and reproduce at constant temperatures never found in its natural habitat. Our results clearly demonstrate the importance of behaviour, rather than pure physiological adaption, in an insect’s persistence in a harsh environment. The Wekiu bug’s shift to carnivory from a suite of herbivorous congeners is a remarkable adaptive shift in an aeolian system bereft of vascular plants. Finally, we relate the specialized life history of the Wekiu bug to its conservation on the arid, frigid summit of the Mauna Kea volcano. This unique habitat is increasingly impacted by tourism and telescope facilities.