Study links acetamiprid exposure to honey bee queen ovary damage

A newly published study in Veterinary Sciences suggests that sublethal exposure to acetamiprid, a neonicotinoid still permitted in the European Union, may damage the ovaries of honey bee queens and trigger overexpression of HSP70 and HSP90, two well-known stress-response proteins. That matters because queen health is a bottleneck for colony survival: when queen fertility slips, the downstream effects can include weaker brood patterns, reduced colony stability, and higher replacement pressure for beekeepers. (food.ec.europa.eu)

The study builds on a long-running shift in pollinator toxicology away from simple mortality endpoints and toward sublethal effects. Acetamiprid has often been described as less acutely toxic to honey bees than some other neonicotinoids, which helped shape its regulatory treatment and reputation. But that “safer” framing has increasingly been challenged by studies showing that low-dose exposure can still alter behavior, development, physiology, and reproduction. The European Commission notes that acetamiprid is among the neonicotinoids approved in the EU, while bee-risk oversight continues to evolve. (food.ec.europa.eu)

That broader literature is especially relevant here because queens remain under-studied compared with worker bees. Earlier research found neonicotinoid pesticides can impair honey bee queen performance and reproductive anatomy, and more recent work has reported that sublethal acetamiprid exposure can suppress pathways linked to juvenile hormone synthesis in queens. Separate recent research has also found chronic neonicotinoid exposure can disrupt survival, development, digestive enzymes, gut microbiome composition, and reproductive quality in queen larvae. Taken together, the new ovarian pathology findings fit an emerging picture in which queen-specific effects may be a meaningful but underappreciated part of pesticide risk. (pmc.ncbi.nlm.nih.gov)

The stress-protein signal is notable in its own right. Heat shock proteins such as HSP70 and HSP90 are part of the honey bee stress response and are known to rise under thermal, infectious, and chemical challenges. Other honey bee studies have reported higher heat shock protein expression after exposure to stressors including pesticides, and a 2026 paper found that simulated heat waves combined with sublethal acetamiprid intensified immune and physiological responses. That suggests the queen findings may have implications beyond a single pesticide-only model, especially as colonies face overlapping burdens from chemicals, parasites, pathogens, and heat stress. (mdpi.com)

Industry and expert commentary on this exact paper appears limited so far, but the surrounding scientific reaction has been consistent on one point: queen and colony-level endpoints deserve more weight in bee risk assessment. A comparative review of bee-testing approaches has argued that short-term lab assessments and microcolony models are insufficient on their own for insecticide risk assessment, while recent reviews focused on acetamiprid say reproductive toxicity remains incompletely characterized. In other words, the new paper doesn’t settle the regulatory question, but it does strengthen the case for looking past acute worker mortality when evaluating pollinator safety. (sciencedirect.com)

Why it matters: For veterinary professionals involved in apiculture, food-animal systems, environmental health, or One Health work, the practical takeaway is that queen-centered reproductive endpoints may be early warning markers of colony compromise. A queen can survive exposure without obvious clinical collapse, yet still show physiological changes that affect egg production, brood quality, or replacement timing. That has implications for advising beekeeper clients on apiary placement, pesticide exposure history, residue awareness, and interpretation of “queen failure” cases where infectious disease alone doesn’t explain colony decline. (pmc.ncbi.nlm.nih.gov)

The paper also reinforces a more general point about sublethal toxicology: low-dose exposure doesn’t have to kill bees outright to become operationally important. Research on acetamiprid has linked exposure with worker developmental effects, altered microbiota, impaired behavior, and immune or endocrine disruption, all of which can interact with queen health and colony performance. For veterinary teams, that means pesticide history belongs in the differential when evaluating chronic colony underperformance, poor brood patterns, or repeated queen turnover. (mdpi.com)

What to watch: The next key question is whether these histologic and molecular findings in queens predict field-level outcomes, including brood viability, supersedure rates, overwinter survival, and productivity, and whether regulators incorporate more queen-specific and multi-stressor endpoints into future pollinator risk assessment frameworks. (food.ec.europa.eu)