Researchers from Purdue University have discovered that honey bees are exposed to high levels of pesticides when they collect pollen from flowering plants placed near agricultural fields.
On May 30, Elizabeth Long and Christian Krupke published a study in which they demonstrate that bees inhabiting near from corn crops collect pollen from plants containing pesticides. The study, published in the journal Nature Communications, used pollen samples from 3 different hives in West Lafayette, Indiana.
According to former research, there is not a single agent related to the decline of honey bees and pollinators, a fact that has lately raised concerns in scientists. On the contrary, the factor may lie in pesticides presented in corn and soybean fields.
Insecticides, such as neonicotinoids, have been widely used in maize and oilseed crops and this substance is widely toxic for environment and bees exposed to it.
Even if the effect of this insecticide has not yet been proved, it is a toxic chemical, which can spread its toxicity beyond the crop field where it is poured. So, the study entitled “Non-cultivated plants present a season-long route of pesticide exposure for honey bees” centered its objectives on determining the exposure of pollinators to pesticides, especially the neonicotinoids. Also, researchers aimed to elucidate the high risks of insecticides in pollen-foraging honey bees and to identify and analyse different sorts of these chemical substances found in crop field environments. Pollen samples were collected and analyzed for crop pesticides during a period of 16 weeks.
Pollen is full with pesticides
Long and Krupke found out that bees collect their pollen from non-cultivated plants, but still contaminated, due to their proximity to crops, and if those non-cultivated plants are contaminated, honey bees get infected too when they try to collect pollen. Scientists analyzed pollen sample from thirty different plant families.
The analysis produced amazing results concerned with high amounts of pesticides found in pollen. The greatest amounts of pesticide were associated to pyrethroids, a household substance generally used to repel insects. Among other pesticides found, researchers have named: phenothrin (ticks’ and fleas repellent), DEET (mosquito repellant) and prallethrin (wasps’ and hornets repellent).
Regarding recent bees decline, Krupke has said that agricultural chemicals are playing a decisive role in this issue. According to him, the pesticide pyrethroids is extremely toxic to bees, even if the quantities found of this pesticide were not high enough to kill bees, it is likely to contribute to their health and subsequently on their decline.
Bee-collected pollen was contaminated by 32 different pesticides, belonging to 9 chemical classes and the most common ones were fungicides and pesticides.