Aberrant cocoons found on honey bee comb cells are found to be Osmia cornifrons (Radoszkowski) (Hymenoptera: Megachillidae)

Authors: POSADA-FLOREZ, FRANCISCO - Volunteer; BLOETSCHER, BARBARA - Ohio Department Of Agriculture; Lopez, Dawn; PAVA-RIPOLL, MONICA - Us Food & Drug Administration (FDA); Rogers, Curtis; Evans, Jay

Submitted to: Journal of Apicultural Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/4/2020
Publication Date: 4/14/2020
Citation: Posada-Florez, F., Bloetscher, B., Lopez, D.L., Pava-Ripoll, M., Rogers, C.W., Evans, J.D. 2020. Aberrant cocoons found on honey bee comb cells are found to be Osmia cornifrons (Radoszkowski) (Hymenoptera: Megachillidae). Journal of Apicultural Research. https://doi.org/10.1080/00218839.2020.1740405.
DOI: https://doi.org/10.1080/00218839.2020.1740405

Interpretive Summary: Apiary inspector Bloetscher was alerted to an unusual cluster of insect casings within an Ohio honey bee colony. Pupal cases for a holometabolous insect (the group including bees, wasps, flies, and beetles) were observed as part of the honey bee comb. This potential risk to honey bees was investigated and the inhabitants of these cells were found to be mason bees, Osmia cornifrons. These are not seen as a threat for honey bees, but the viability of these cells (which were developing normally into pupal bees) suggests nestsite use by mason bees in honey bee hives, and potentially coexistence. The results are important for regulators and the viability of these bees suggests a novel means for raising solitary bees like Osmia, assuming the bees can emerge healthy and in the appropriate sex ratios.

Technical Abstract: The importance of identifying potential invasive species using morphological and molecular procedures is imperative for the prevention of possible threats and must be performed quickly, before making disruptive and costly decisions. Recently, a solitary bee, Osmia cornifrons (Hymenoptera: Megachillidae) , was found nesting within cells comb of Apis mellifera (Hymenoptera:Apidae) shedding light on the diversity of biological behaviors and interactions with other bee species. O. cornifrons females have some plasticity when selecting nesting resources, and, upon discovering honey bee comb, could use this resource for nesting cavities. They may even use stored pollen resources to help provision offspring. This might happen in abandoned honey bee combs. Another possibility is that resident honey bees do not object to the presence of solitary bees nesting in the combs, and therefore acted as surrogates. Here we described numerous Osmia cornifrons cocoons in honey bee cells from one bee hive in Ohio. Since the cocoons were attached to one another with honey bee wax it is conceivable that honey bee hosts were present as this nest sharing took place. This diagnosis demonstrates a possibility for mass production of O. cornifrons pollinators using flat sheets with holes, similar to honey bee comb, luring them with pollen for O. cornifrons nesting and reproduction.