Effect of temperature on the post-diapause development rate, survival, and body mass of the solitary wasp Isodontia elegans  

We examined the relationship of post-diapause rearing temperature to developmental rate, survival, and adult body mass of the solitary wasp Isodontia elegans using prepupae from trap-nests. Isodontia elegans is a member of a genus often found in trap-nests in North America and Europe. Trap-nests are commonly used tools for studying cavity-nesting solitary wasps and bees. In temperate zones, progeny in nests usually overwinter as fully prepupae before pupating and emerging as adults. An important aspect of properly using trap-nests is determining temperatures that affect survival and health of developing offspring.  After overwintering >600 cocoons containing prepupae after the summers of 2015 and 2016, we placed cocoons on a laboratory thermal gradient where offspring experienced one of 19 constant temperatures from 643°C; emergence of adults was monitored for 100 days.  Our conservative estimate for the critical thermal minimum for development is 14°C, whereas that for the critical ..., Source of the wasps  
Isodontia elegans cocoons were obtained from trap-nests placed at sites within several km of Hillsboro, Oregon (45°31’ N, 122°59’ W; Spendal et al., 2021). Cocoons were removed from nests in late September in 2015 and early October in 2016. Cocoons were stored at ambient temperature in a barn in Oregon, before transport to Montana State University (Bozeman, MT) in November where they were kept at 8°C, 80% relative humidity until the following April 20 of each year. Cocoons were placed in #00 gelatin capsules, each with its long axis parallel to the capsule; the ends of the capsules had been punctured with pinholes to provide ventilation. In 2016, we measured cocoon mass (MC) prior to overwintering with a Metler AT 250 analytical balance accurate to 0.1 mg, and gave each gelatin capsule a unique numerical code.  
Rearing wasps on Thermal Gradient
On 20 April of 2016 and 2017, we removed gelatin capsules containing I. elegans cocoons from winter storage, at which tim...,