{"id":38322,"date":"2025-04-25T00:01:58","date_gmt":"2025-04-25T04:01:58","guid":{"rendered":"https:\/\/beyondpesticides.org\/dailynewsblog\/?p=38322"},"modified":"2025-04-25T09:05:57","modified_gmt":"2025-04-25T13:05:57","slug":"male-fertility-and-reproduction-in-bee-species-threatened-with-systemic-insecticide-exposure-study-finds","status":"publish","type":"post","link":"https:\/\/beyondpesticides.org\/dailynewsblog\/2025\/04\/male-fertility-and-reproduction-in-bee-species-threatened-with-systemic-insecticide-exposure-study-finds\/","title":{"rendered":"Male Fertility and Reproduction in Bee Species Threatened with Systemic Insecticide Exposure, Study Finds"},"content":{"rendered":"

(Beyond Pesticides<\/em>, April 25, 2025) A novel study in Chemosphere<\/em><\/a> finds impacts on male fertility in a bee species (Osmia bicornis<\/em>) with exposure to sulfoxaflor<\/a>, a systemic sulfoximine insecticide with similar mechanisms to neonicotinoids<\/a>. \u201cFor the first time, we demonstrate that short-term chronic, field-realistic exposure to a common pesticide reduced pre-copulatory display (36%) and sounds (27%) [courtship behaviors], increased the number of copulations (+110%) and the mating duration (+166%), while finally reducing sperm quantity (25%) and mating success (43%),\u201d the researchers report. They continue, \u201cOur research raises considerable concern on the impact of field-realistic, low sublethal pesticide levels on the fertility and reproductive success of pollinators<\/a>.\u201d<\/p>\n

Mating behaviors and the ability to successfully reproduce determines the survival of species. As the authors state: \u201cMating disorders may therefore contribute to the recent decline in insect and pollinators’<\/a> health worldwide. While the impact of pesticides on pollinators is widely considered as a driving factor for reducing pollinators’ health, their effect on mating behaviour and male fertility remains widely overlooked.\u201d<\/p>\n

The red mason bee (O. bicornis<\/em>) can \u201cprovide essential pollination service for both crops and wild plants sustaining food production and biodiversity while serving as a bioindicator of environmental health.\u201d The abundance and diversity of pollinators has been declining globally, as documented<\/a> in scientific literature, which puts biodiversity and the production of pollination-dependent crops at considerable risk. The researchers also reference mounting evidence (see here<\/a>, here<\/a>, here<\/a>, and here<\/a>) that \u201csuggests that environmental pesticide pollution can negatively affect insect biomass and diversity, including bees.\u201d<\/p>\n

They continue by saying: \u201cPesticides can cause both lethal and sublethal negative effects on bees, individually or in combination with other stressors<\/a>. These effects include impairments in learning and memory, decision time, feeding behaviour, ovary development, colony functionality, nesting behaviour, immune response, motor functions and phototaxis, respiratory rhythm, thermoregulation, orientation and navigation, and flight abilities. However, our understanding of how pesticide exposure may affect insect mating, fertility and reproductive physiology remains scarce, in particular for solitary bees.\u201d (See studies here<\/a>, here<\/a>, here<\/a>, here<\/a>, here<\/a>, here<\/a>, here<\/a>, and here<\/a>.)<\/p>\n

Within the study, the experiment was conducted over the course of seven weeks and evaluated mating behaviors that include mating choice, pre-copulatory display, pre-copulatory sound, mating success, post-copulatory display, and post-copulatory vibrations, as well as other behaviors such as food consumption. The results highlight that sulfoxaflor exposure alters the pre-mating behaviors of O. bicornis<\/em> males and subsequent mating success.<\/p>\n

By reducing males\u2019 mating displays and sounds, this lowers the likelihood of males being accepted by females. Observed successful mating also requires almost three times longer for the pesticide-exposed males within the experiment, which could endanger the bees and increase the risk of predation during the process. \u00a0<\/p>\n

The authors report: \u201cOverall, there was a significant negative effect of sulfoxaflor on the mating success of male bees, resulting in 43% fewer successes in the pesticide group (50%) as compared to the control group (87%). Consequently, sulfoxaflor exposure significantly reduced the occurrence of post-copulatory display and post-copulatory vibrations… Our novel results demonstrate that sublethal, field-realistic pesticide exposure can turn mating into a long, risky, and unsuccessful process in solitary bees.\u201d<\/p>\n

The data reveals that sulfoxaflor can negatively affect mating behavior, mating success, and male fertility, which is \u201clikely explained by the pesticide altering the central nervous system of bees, thereby impairing their cognitive, sensory, and motor abilities as well as reproductive behaviour and physiology.\u201d (See studies here<\/a>, here<\/a>, and here<\/a>.) The researchers continue, saying: \u201cThe observed findings highlight that pesticides can reduce male fitness which may inevitably lead to drastic consequences at the population level. The data offer a plausible mechanistic explanation for the ongoing decline of wild bee populations and underscore the urgent need to find sustainable solutions in agriculture that safeguard pollinators and biodiversity<\/a>.\u201d<\/p>\n

Behavior impairments not specific to reproduction, such as the observed increased hyperactivity and food consumption, are also of concern, as locomotion and coordination are essential for flight ability and the success of foraging. \u201c[T]he behavioural impairments shown here may impact the quality of the pollination service provided by bees. The increased hyperactivity caused by pesticide-treated bees may have consequently increased bee energy \u2013and thus food \u2013 consumption,\u201d the researchers postulate.<\/p>\n

As a result, the authors conclude by saying: \u201cWe reveal that pesticides alter bee behaviours before, during, and after mating. This may translate to wider fitness impairments, including alterations on the ability of bees to forage, defend territories against competing males, and find females.\u201d<\/p>\n

Previous research supports these findings, which the researchers reference from the following studies:<\/p>\n