Monarch butterflies (Danaus plexippus) lay eggs on milkweed (Asclepias spp.) throughout the northern portion of their range during the breeding season, but the reduction in milkweed abundance is thought to partly contribute to the declines observed in the northeastern population of monarchs. Pictured here is the final instar of the last breeding generation of the monarch butterfly, eating away at swamp milkweed (A. incarnata), for the 2017 field season taken in North Perth, Ontario. As part of the monarch research team in the Norris Lab at the University of Guelph, we were fortunate to spend the day out looking for breeding butterflies in order to obtain eggs that will be used for studies examining the effect of the neonicotinoid pesticide clothianidin on their development and behaviour.
