Romance in peril: pesticide exposure impacts bee courtship, mating, and fertility

A new international study led by the University of Turin has uncovered a sneakier side effect that pesticides may elicit on wild bees: they mess with courtship, mating, and fertility. Yep, even bee romance is in trouble because of chemical pollution.

Published in the journal Chemosphere, the study is the first to show that even low doses of pesticides can disrupt the love life of one of the world’s most important pollinators: the red mason bee (Osmia bicornis). After exposure to the chemical compound, bees became slower, less efficient in their mating rituals, and significantly less fertile — male bees, in particular, produced less sperm.

This research, featuring scientists from Italy, Spain, Switzerland, and Poland, was led by Luis Velez-Trujillo, a PhD student at UniTo’s BeeLab, and coordinated by Simone Tosi, professor in the Department of Agricultural, Forest, and Food Sciences.

But this goes way beyond bees. The findings highlight a deeply concerning impact of human-caused stressors — like pesticides — on animal behavior and health. When something as fundamental as courtship and sperm quantity gets altered, the ripple effects on reproduction, population growth, and ecosystem balance can be massive.

As Prof. Tosi puts it:

"These results raise serious concerns about the reproductive health of pollinators — and potentially many other animals — when exposed to low, common contaminant levels. Reducing environmental pollution isn’t just important anymore; it’s urgent if we want to protect biodiversity and safeguard life — ours and that of future generations.”

Vélez-Trujillo L, Carisio L, Popiela E, Straub L, Tosi S (2025). Romance in peril: A common pesticide impairs mating behaviours and male fertility of solitary bees (Osmia bicornis). Chemosphere, 377, 144335. https://doi.org/10.1016/j.chemosphere.2025.144335

https://www.otto.unito.it/it/articoli/la-riproduzione-delle-api-e-pericolo-causa-dei-pesticidi