Sites chosen by diapausing or quiescent stage quino checkerspot butterfly, Euphydryas editha quino, (Lepidoptera: Nymphalidae) larvae

摘要

This study examines whether in nature endangered quino checkerspot (Euphydryas editha quino) larvae will return to diapause and if so where they choose to hide. Multiple years of diapause probably help larvae survive drought years and sites chosen have high survival value to the species. Ninety square meters of habitat were created by removing non native plants and replacing them with natives found at checkerspot occupied sites. During the 2005-2006 winter 1,000 post-diapause larvae were released. From these larvae 31 adults (20 males and 11 females) developed over a 2.5 month period (March 20-June 6) from 41 pupae. One chrysalis was parasitized by a parasitic wasp Pteromalus puparum (L.) in the family Pteromalidae, one was partially eaten by an animal, while the remaining eight pupae died of unknown causes. Thirty quadrats (1 square meter each) were cleared of vegetation, leaf and branch litter, rocks, and checkerspot larvae from July 5 to August 1, 2006. Forty-nine larvae were found that returned to diapause. Most larvae (31) chose to make shelters on California buckwheat, which is not a checkerspot food plant, two to five cm above the ground. One shelter had 22, another had seven, and two others had single larvae. Five of 10 larvae found in leaf litter below California buckwheat were crawling and not associated with shelters suggesting they had been dislodged from shelters. California buckwheat may be important in habitat restoration for the checkerspot, particularly at sites below 900 meters elevation where summer conditions are hot and dry. No additional larvae were found the following spring, when they should have exited diapause. Therefore 910 (91%) larvae were lost to some undocumented form of mortality.