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Environmental impacts on diapause and survival of the alfalfa leafcutting bee, Megachile rotundata

Citation

Wilson, Elisabeth et al. (2021), Environmental impacts on diapause and survival of the alfalfa leafcutting bee, Megachile rotundata, Dryad, Dataset, https://doi.org/10.5061/dryad.dfn2z3527

Abstract

Megachile rotundata exhibits a facultative prepupal diapause but the cues regulating diapause initiation are not well understood. Possible cues include daylength and temperature. Megachile rotundata females experience changing daylengths over the nesting season that may influence diapause incidence in their offspring through a maternal effect. Juvenile M. rotundata spend their developmental period confined in a nesting cavity, potentially subjected to stressful temperatures that may affect diapause incidence and survival. To estimate the impact of daylength and nest cavity temperature on offspring diapause, we designed a 3D printed box with iButtons that measured nest cavity temperature. We observed nest building throughout the season, monitored nest cavity temperature, and followed offspring through development to measure diapause incidence and mortality. We found that daylength was a cue for diapause, and nest cavity temperature did not influence diapause incidence. Eggs laid during long days had a lower probability of diapause. Siblings tended to have the same diapause status, explaining a lot of the remaining variance in diapause incidence. Some females established nests that contained both diapausing and nondiapausing individuals, which were distributed throughout the nest. Nest cavities reached stressful temperatures, which decreased survival. Mortality was significantly higher in nondiapausing bees and the individuals that were laid first in the nest. In conclusion, we demonstrate a maternal effect for diapause that is mediated by daylength and is independent of nest box temperature.

Methods

Temperature data was collected via iButtons placed in the nest block. The diapause status was each individual was determined by x-ray. Further details on the collection and processing of the data can be found in the manuscript, which is open access.

Usage Notes

The ReadMe file includes descriptions of the column headings in the dataframe.

Funding

National Science Foundation, Award: RII Track-2 FEC 1826834

National Science Foundation, Award: IOS-1557940

Agricultural Research Service, Award: 3060-21220-032-00D