Bees and Fish Warn: What Are the Unexpected Effects of Pesticides? The "Invisible Chain" of Crop Protection Agents

"The Same Field Spray Shakes Both Nest and Stream"

A study reported by Phys.org on November 6, 2025, visualized the impact of plant protection products (PPP: insecticides, herbicides, fungicides) on "non-target organisms" across two habitats: land and water. The model organisms were the pollinating honeybee (Apis mellifera) and the aquatic standard species zebrafish (Danio rerio). When exposed to "concentrations that could realistically occur in the environment," both showed significant behavioral changes—this is the conclusion of the study.Phys.org

How Was It Verified

The paper was published in Environment International (peer-reviewed). In the beehives, behavior was observed over time using a snapshot method from days 3 to 10 of exposure. For fish embryos, the VAMR method was applied to continuously screen 26 motor responses to visual and acoustic stimuli. The substances exposed were insecticide flupyradifurone, fungicide boscalid, and herbicide terbuthylazine, all representative components detected in European farmlands and small streams.

Observed "Discrepancies in Ways of Life"

In bees, foraging and nectar processing declined with insecticides, while caregiving (brood care) behaviors diminished with fungicides and herbicides, showing different "weakening" patterns for each agent. In fish embryos, movement patterns reflecting learning, memory, and neural activity were altered. The crucial point is "when mixed." In cocktails close to the composition ratios found in German small streams (e.g., boscalid 41.54%, flupyradifurone 0.013%, terbuthylazine 58.45%), a phenomenon was observed where dominant behavior "slides" from herbicide-like at low concentrations to fungicide-like at higher concentrations.Phys.org

Why "Non-Lethal" is Important

Current risk assessments tend to focus on endpoints like mortality and growth inhibition. However, ecological services of organisms—such as pollination, feeding, avoidance, and learning—are supported by behavior itself. The authors of this study propose institutionalizing complex behavioral tests at low concentrations and setting permissible values based on cumulative risks (mix effects).Phys.org

Social Media Reactions: What Voices Spread

• Science Aggregators: On news aggregation services like SciURLs, this topic spread in the environment and ecology categories, accompanied by commentary highlighting the importance of behavioral indicators.SciURLs

• Facebook Shares: The article was shared on Phys.org's official page, where comments reflected interest in the "sub-lethal" effects of pesticides.facebook.com

• Related Discussions on Reddit: In threads about individual components and pollinator decline, many voices emphasized "widespread effects on non-target organisms even at low doses" and the need to evaluate mixed exposures. Participants acknowledged the new measure of "behavioral changes" indicated by this study.Reddit

※The social media reactions in this article are summarized from recent public posts and related topic threads, with representative points highlighted (specific names and personal post details are omitted).

Background Context: Detection Reality and Current Regulations

Residues of boscalid and terbuthylazine, among others, have been repeatedly reported from bee bread and pollen in various countries. In the EU, these are still in use with organized applications and MRLs, making "cumulative environmental exposure" unavoidable. Hence, evaluation axes beyond single-agent and acute assessments are needed.PMC

Where Policy Measures Can Be Taken

1. Evaluation Updates: Incorporate "behavioral indicators" and "mixture evaluation" as mandatory items during registration and re-evaluation (authors' suggestion).Phys.org

2. Watershed-Based Monitoring: Combine regular monitoring in small streams with water sampling after peak runoff (post-rainfall) to grasp the "real cocktail."ufz.de

3. Implementation Innovations: Enforce existing best practices such as drift-reducing nozzles, adherence to wind speed and direction, setting river buffer zones, and timing considerations for spraying around hives (avoiding flowering periods and daytime).

4. Producer-Pollination Service Collaboration: Systematize operations to reduce exposure through prior communication with beekeepers and sharing of flowering calendars.

5. Addressing Research Gaps: Long-term tracking at the hive and colony levels, reproduction under semi-natural field conditions, and elucidation of interactions with other stresses (e.g., warming, parasitic mites). Scaling up from behavior to community to services (pollination, feeding) is key.ACS Publications

Limitations and Interpretation of the Study

This study was conducted under strict lab (/semi-natural) conditions and does not encompass all "complex stresses" in the wild. However,the fact that "behavior" at the organism level changes even at low concentrationswas simultaneously demonstrated in both bees and fish, the dual pillars of ecosystems. This aligns with preceding and concurrent studies (e.g., long-term neurobehavioral effects in fish), underscoring the necessity of behavioral toxicology.PubMed

Conclusion: Changing What We Measure Increases What We Can Protect

The era of "safe if not lethal" is over. If foraging slows, the hive will eventually weaken. If learning slows, juvenile fish find it harder to survive. Including "behavior" in the evaluation metrics is not about imposing undue burdens on the field, buta shortcut to protecting the functions we truly want to safeguard (pollination, resource cycling). The insights from this study clearly point in that direction.Phys.org