The impacts of the non-native Houdini fly on blue orchard bees

Commodities

• Animals: bees

Practices

• Animal Production: animal protection and health, parasite control
• Crop Production: pollinator health
• Education and Training: display, networking, participatory research
• Natural Resources/Environment: wildlife
• Pest Management: field monitoring/scouting, prevention
• Sustainable Communities: urban agriculture

The introduction of non-native species poses major risks in agriculture, with hundreds of new alien species recorded annually. Most efforts to understand the risks and effects of non-native species have focused on mitigating the impact of invasive crop pests. However, non-native species can also affect critical services and the organisms providing them. For example, honey bee (Apis mellifera) declines caused by Varroa mites have led to significant crop losses and increased management costs for beekeepers. Houdini flies (Cacoxenus indagator) were recently introduced to the United States and parasitize cavity-nesting native bees, including the blue orchard bee (Osmia lignaria), a managed solitary bee used to pollinate spring orchard trees. The introduction of Houdini flies poses an existential threat to the stability of the solitary bee industry and the livelihoods of orchard managers. To date, there are no published studies on Houdini flies in their introduced range. We must understand Houdini fly infection dynamics and dispersion capability to contribute meaningfully to management practices and bolster solitary bee populations, beekeepers, and orchard managers. This project aims to address this knowledge gap through a hierarchical series of approaches: O1) longitudinal field monitoring of parasitism rates to determine temporal patterns and long-term impacts of Houdini fly parasitism, O2) a semi-field experiment to assess population impacts on blue orchard bees, and O3) a manipulative chamber experiment to quantify the environmental tolerance and establishment potential of Houdini flies. We will determine how Houdini fly parasitism rates are changing over time, how they may impact cavity-nesting bee populations, and if management strategies should prioritize preventing the spread of Houdini fly or controlling existing populations. Educational efforts will include O4) online outreach to bee enthusiasts, O5) presentations to producers at two stakeholder meetings, and O6) academic publication and presentation.

Research Objectives:

1) Longitudinal field monitoring of Houdini fly parasitism rates: We will quantify the annual parasitism rates of Houdini flies on BOBs over multiple years to assess temporal patterns and long-term changes in parasitism at nest-block sites.

2) Semi-field experiment to assess BOB population impacts: We will conduct controlled semi-field experiments using flight cages to measure BOB vital rates when exposed to Houdini flies to assess population impacts on BOBs.

3) Manipulative chamber experiment to determine establishment potential: We will determine the environmental thresholds for Houdini fly survival by rearing them under various temperature and humidity conditions to understand their potential to establish in states neighboring infected areas.

Educational Objectives:

4) Online outreach to bee hotel owners and bee enthusiasts: We will perform online outreach to this group through six short form videos and two infographic social media posts.

5) Presentation of findings to bee producers at two stakeholder meetings: We will present research progress and findings to producers at the Orchard Bee Association annual meeting, which brings together many stakeholders and researchers to discuss industry related issues and management strategies for the sustainable production of BOBs. Additionally, we will create a fact sheet that can be shared by producers.

6) Academic publication and presentation to disseminate results to researchers: We will present findings from this project through a presentation at an academic conference and the publication of a peer-reviewed journal article. Through collaboration and discussion with others in our field, we hope to ensure the longevity of this research.