Evolution of DWV Virulence and Honey Bee Defensive Responses in Puerto Rico

Commodities

Practices

This project investigates how Deformed Wing Virus (DWV) has evolved in Puerto Rico and how gentle Africanized Honey Bees (gAHB) defend themselves against infection across developmental and behavioral contexts. Puerto Rico represents a unique natural system where DWV circulates widely, Varroa destructor is present, yet colony losses remain low and bees exhibit strong resistance. This project integrates viral genomics, immune responses, developmental susceptibility, and behavioral impacts to determine how DWV virulence, host defenses, and transmission pathways interact in this system. We will characterize DWV genetic variation using Illumina sequencing and Nanopore long‑amplicon sequencing to identify viral evolution and potential new variants. Controlled infection assays will quantify resistance across larval, pupal, and adult stages, including the potential role of Sacbrood Virus (SBV) in modulating DWV replication. Behavioral experiments will evaluate how DWV affects orientation, learning, memory, and neural viral loads, testing whether viral evolution favors subtle behavioral manipulation rather than Varroa‑dependent transmission. This project aims to identify the DWV variants circulating in Puerto Rico, determine how gAHB resist infection, and understand how viral evolution shapes the transmission dynamics. These findings will support sustainable beekeeping by reducing colony losses, minimizing chemical treatments, and strengthening pollination services essential for agriculture in the Southern SARE region.

Objective 1. Identify and characterize DWV genetic variation in Puerto Rican honey bees using Illumina NovaSeq and Nanopore sequencing. Determine whether DWV has evolved reduced virulence, whether new variants have emerged, and whether Puerto Rico have a distinct DWV lineage, which will refer to as DWV-PR.

Objective 2. Evaluate antiviral resistance mechanisms in gAHB across larval, pupal, and adult stages using controlled DWV infection assays. Measure viral titers, immune responses, and developmental susceptibility.

Objective 3. Determine how DWV affects adult honey bee orientation, learning, memory, and neural viral loads. Test whether DWV variants associated with reduced virulence exhibit behavioral manipulation strategies that influence transmission pathways.

Puerto Rico provides a uniquely powerful system for studying the coevolution of DWV, Varroa destructor, and gAHB. Unlike many temperate regions where DWV‑A and DWV‑B are strongly associated with colony collapse and high winter mortality (Martin et al., 2012; Barroso‑Arévalo et al., 2019), Puerto Rican colonies maintain high survival and productivity despite long‑term Varroa pressure and detectable viral loads (BIP & USDA, 2019a; 2020b; Fahey et al., 2019). Together, these factors make Puerto Rico an exceptional natural laboratory for investigating how viral evolution, host resistance, and behavioral impacts interact to modulate virulence.