Large milkweed bugs (Oncopeltus fasciatus:Hemiptera) are widely distributed from Costa Rica to southern Canada. Most studies of the ecology of O. fasciautus, however, have been limited to a small number of sample sites within the species range, leading to ecological inferences that are spatially and temporally limited. Citizen science images provide a more comprehensive dataset, spanning the extent of the range and yearly activity period. We evaluated citizen science images from iNaturalist for the number of insect individuals depicted, their life stage, and reproductive status as well as the part of the plant the insects occupied. The goal was to confirm life history patterns related to moisture availability and temperature and their influence on clutch size and breeding phenology but also to test the assumptions over wider scale and finer gradients of abiotic factors.
Results/Conclusions
Our analysis of citizen science images depict O. fasciatus pairs naturally mating on previously undocumented species, suggesting broader host plant range. Mating pairs were most often observed on the immature milkweed pods (28.9%), followed by flowers (24.1%), and leaves (20.6%). Additionally, results confirm that the timing and duration of the breeding period of O. fasciatus varies along the longitudinal gradient of their range, with a single sharp peak in the northern extent of the range, two peaks in the mid-range, and near-continuous breeding throughout the year in the southern extent of the range. The images also reveal that the number of subadults in O. fasciatus clusters varies by the part of the plant the clusters occupy, with clutch sizes twice as large on immature pods compared with mature pods. These results provide a wide-ranging study of the breeding ecology of O. fasciatus across its range and demonstrate the potential of using citizen science contributed images to assess ecological and life history questions beyond species occurrence, range-shifts, or climate-related phenomena.