Study explores little-understood effects of soil exposure on subterranean colonies — ScienceDaily
The results of a new study suggest that bees may be exposed to pesticides in more ways than we think, and may significantly affect their development.
This study, published in Nature's Science Report examines the non-target effects of pesticides on nesting bees on the ground, which actually constitute the majority of bee species. Non-target effects refer to the effects on organisms other than expected. Much of the current research on the non-target effects of pesticides is limited to honey and bumblebees and exposure to pesticides when collecting pollen and nectar.
While these previous studies have shown that pesticide consumption by honey and bumblebees may have important ecological consequences, this new study is one of the first to determine the effects of exposure to pesticides, such as those occurring in the soil. Other bee species may be encountered.
"This is an important job because it is one of the first studies to study the actual concentration of pesticides. You will find that they will act as a pathway for bees in the soil. This is an inexperienced route, especially Nick Anderson, an entomologist, led his research with his consultant, entomology professor Alex Harmon-Threatt.
The key difference between ground nesting bees and their honey and bumblebee cousins is the smaller nest size (including size and number of bees) they form by excavating the soil. Bee species that nest in this way can stay underground for up to 49 weeks in a year, and can only feed, mate and lay eggs within 3 weeks. This allows the bees to have a lot of exposure to chronic low levels of pesticides found in the soil after use in agricultural land.
Researchers are particularly interested in a class of insecticides called neonicotinoids. Neonicotinoid is derived from nicotine and is widely used for its effectiveness against insects such as Japanese beetles and jade mites, but they are toxic to pollinators. Their half-life is also very long, which means they can stay in the soil for a long time. The bees used by Anderson and Harmon-Threatt are very close to ground nesting species because they are more suitable for testing in the laboratory and have been used in previous studies to approximate the effects of ground nesting species.
When bees were exposed to neonicotinoids in the laboratory, the levels observed by the researchers were similar to those found in the wild. The results showed that the female became larger, the growth time was not longer, the male was smaller, and the life span was longer. This conclusion suggests that long-term and low-level exposure to pesticides may cause bees to respond, and in the case of low levels of pesticide exposure, bees seem to benefit in a smaller way. However, the long-term effects of some of these changes may not be obvious. Researchers believe that these lower doses are causing changes in the development of bees, such as transferring energy from normal developmental processes to enhance physical and biochemical barriers against the effects of pesticides.
"When you are working on neonicotinoids like bees, I think people expect the conclusions to be good or bad, but many of the relationships we see are more complicated than this. Many factors and developments The process can be affected," Harmon-Threatt said.
"When we develop new pesticides, we must be able to understand the effects," Anderson said. “Our work is part of this risk assessment. We want to know what impact it has on the ground nesting bees so that when we use the land for agriculture or try to recover it, we can minimize the impact on these species. "
This study laid the foundation for the Harmon-Threatt laboratory to expand its work in the field over the next five years. In 2018, Harmon-Threatt received a $1 million grant from the US Department of Agriculture's National Institute of Food and Agriculture for research to better understand the role of soil pollution in the diversity and conservation of bees.
Important note :