Description of Equipment and Needs: For experiments planned to begin in the early summer months of 2025, a temperature regulated incubator is needed to provide an environment where temperature and light can be controlled while monitoring honey bee and mite survival in the days following the new management tool exposure, the bioinsecticide Spear-T®. This incubator will be placed in a room adjacent to our laboratory, located at the Cornell AgriTech campus in Geneva, NY. This room is designed to house incubators and temperature-controlled chambers. Our lab is located ~4 miles from the research farms where hives for this research are located. Additionally, 1 Eppendorf® Repeater™ E3/E3x is required to perform serial dilutions to prepare concentrations of Spear-T® and highly concentrated positive controls (amitraz and thiamethoxam) with precision for laboratory bioassays.

Impact of Equipment on Beekeeping Research: Varroa prevalence is one of the primary factors attributed to honey bee colony collapse. There is an urgent need for new tools to manage these mites as well as Tropilaelaps, the next ectoparasite threat expected to affect the honey bees, beekeepers, and fruit and vegetable growers in North America. Current tools are not always convenient, can be hazardous, and often become ineffective as mites develop resistance. In 2025, we will assess the potential of Spear-T® bioactive peptide, an eco-friendly alternative to synthetic chemical pesticides, pollinator-safe, and already FDA-approved product, for use in the hive environment against Varroa. An Eppendorf® Repeater™ E3/E3x and Incubator will make for more controlled experiments with enhanced precision when carrying out the bioassays.

Spear-T® is a commercial biopesticide on the market to manage small field pests including thrips and aphids. The active ingredient is a peptide, GS-omega/kappa-Hxtx-Hv1a, found in the venom of the Australian Blue Mountains Funnel Web spider (Hadronyche versuta). Research by Nakasu et al. (2014) found that the peptide itself is not harmful to foraging bees, thus inspiring the idea that Spear-T® could be a promising tool for in-hive management of Varroa. Our work will test the formulated, commercially available product and will conduct toxicity bioassays, informed by OECD protocols, on nurse bees in addition to the targeted pest, mature female Varroa mites. Four experiments will be carried out to meet the following three objectives: i) Assess efficacy of Spear-T® bioinsecticide on Varroa destructor mortality, ii) assess the acute and chronic oral toxicity of Spear-T® on honey bee health, iii) determine the Spear-T® peptide degradation in hive products including honey, pollen, and wax.

To measure chronic and acute oral toxicity on honey bees to ensure that the product is safe for future in-hive application, bees will be collected from hives in groups of 10. These bees will be placed in a dark incubator set to ~25°C and ~70% relative humidity. After a short starvation period, bees will be allowed to feed ad libitum on a designated concentration of Spear-T®, positive control (Thiamethoxam), or sugar syrup. For the acute oral toxicity experiment, feeders will be replaced with sugar syrup after 24 hours. Survival of bees in each treatment group will be recorded in the days following initial feeding to determine the product’s acute and chronic oral LD50 for nurse honey bees. The cuticular toxicity of Spear-T® on Varroa mites will be assessed by putting groups of 10 mites into vials coated with varying concentrations of product. Similarly, mite mortality will be assessed in the days following exposure and compared to positive (amitraz) and negative (weak Tween 20 solution) controls.

Preliminary results: A cuticular toxicity bioassay was performed on nurse bees during the summer of 2024 and supports that nurse bee survival is not impacted by cuticular contact with even high concentrations of Spear-T®. This is encouraging as we embark on further study of this biological insecticide.

Budget Justification:
Materials and Supplies: Funds ($7,500, in Year 1) are required for supplies to carry out the proposed research for the cuticular toxicity bioassay of Spear-T® on nurse bees and Varroa mites as well as acute oral toxicity experiment of Spear-T® on nurse bees during the spring and summer of 2025. The incubator will provide sufficient space to house all containers of bees for a single replicate of either the acute or chronic oral toxicity bioassay. This will ensure that all treatment groups of a single replicate will be exposed to the same environmental conditions. This equipment grant will provide the space capacity necessary to carry out the multiple experiments (with replicates) that we have planned for the summer of 2025. The electronic pipette Eppendorf® Repeater™ E3/E3x will allow the researchers to add small and precise amounts product (Spear-T®, amitraz, and thiamethoxam) when preparing treatments of varying concentrations. Precision is important as fresh solutions will be made between replicate trials.

PI Information: Christophe Duplais, Associate Research Professor, Department of Entomology, Cornell University, c.duplais@cornell.edu

Co-Investigator Information: Peta Hafker, Entomology PhD student conducting described experiments, Cornell University, pfh44@cornell.edu
Nakasu, E. Y., Williamson, S. M., Edwards, M. G., Fitches, E. C., Gatehouse, J. A., Wright, G.
A., & Gatehouse, A. M. (2014). Novel biopesticide based on a spider venom peptide
shows no adverse effects on honeybees. Proceedings of the Royal Society B: Biological
Sciences, 281(1787), 20140619. https://doi.org/10.1098/rspb.2014.0619