Osmia cornifrons invasion risk is increased by commercially produced populations of Osmia lignaria deployed in the Sacramento Valley, California

Authors: HEINER, SHANNON - University Of Utah; McCabe, Lindsie; Koch, Jonathan

Submitted to: Biological Invasions
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/22/2025
Publication Date: 7/5/2025
Citation: Heiner, S., Mccabe, L.M., Koch, J. 2025. Osmia cornifrons invasion risk is increased by commercially produced populations of Osmia lignaria deployed in the Sacramento Valley, California. Biological Invasions. https://doi.org/10.1007/s10530-025-03597-2.
DOI: https://doi.org/10.1007/s10530-025-03597-2

Interpretive Summary: Osmia cornifrons, a mason bee indigenous to Northern Asia, has been used as a non-native alternative pollinator for early spring orchard crops in the eastern United States of America (USA) since the 1980s. Since their introduction, O. cornifrons has become established in the mid-Atlantic region of the USA, and most recently in Toronto, Canada and the Pacific northwest of the USA. Recently, we identified O. cornifrons co-nesting in an almond orchard in the Sacramento Valley, California, USA after the deployment of a commercially reared population of O. lignaria. The origin of the intercepted O. cornifrons is from a commercially produced O. lignaria population from Washington state. From the O. cornifrons population, we identified two genetic haplotypes that are identical to haplotypes found in Ohio, Virginia, and South Korea. Our results suggests that commercially produced O. lignaria is a pathway that may facilitate the spread of non-native O. cornifrons in the western USA unintentionally.

Technical Abstract: Osmia cornifrons, a mason bee indigenous to Northern Asia, has been used as a non-native alternative pollinator for early spring orchard crops in the eastern United States of America (USA) since the 1980s. Since their introduction, O. cornifrons has become established in the mid-Atlantic region of the USA, and most recently in Toronto, Canada and the Pacific northwest of the USA. Recently, we identified O. cornifrons co-nesting in an almond orchard in the Sacramento Valley, California, USA after the deployment of a commercially reared F0 population of O. lignaria. The origin of the intercepted O. cornifrons is from a commercially produced O. lignaria population from Washington state. From the O. cornifrons population, we identified two mitochondrial haplotypes that are identical to haplotypes found in Ohio, Virginia, and South Korea. Haplotypes 1 and 2 were recovered from the F1 generation that were produced in the almond orchards at the end of the pollination season by the F0 generation. Furthermore, the F1 generation was recovered from nests that were constructed <1 to 4 km away from the orchard were the F0 generations were deployed. Contrary to earlier studies, our results demonstrate that O. corniforns females can disperse farther than 1 km from their natal site in search of suitable nesting sites, exceeding the known dispersal distance of a closely related Osmia species. Our results suggests that commercially produced O. lignaria is a pathway that may facilitate the spread of non-native O. cornifrons in the western USA unintentionally.