"Current ecological risk assessments of pesticides on pollinators have primarily considered only laboratory conditions. For the larvae of solitary bees, ingestion of provisions contaminated with pesticides may increase the mortality rate of the larvae, decrease the collection rate and the population of adult solitary bees in the next year from a demographic perspective.
But there are limited studies on the effects of pesticides on the larvae of solitary bees. Therefore, understanding how pesticides influence the larvae of solitary bees should be considered an integral part of pesticide ecological risk assessment.
presents a method to expose the larvae of solitary bee, Osmia excavata, to lethal or sublethal doses of pesticide, tracking larval weight gain, developmental duration, eclosion ability, and food consumption efficiency conversion of ingested food.
To demonstrate the effectiveness of this method, the larvae of O. excavata were fed with provisions containing acute leth al and sublethal doses of chlorpyrifos. Then, the above indexes of the treated larvae were investigated.
This technique helps to predict and mitigate the risk of pesticides to pollinators." This is what the researchers of the study published in the Journal of visualized experiments, entitled Evaluating the Effect of Pesticides on the Larvae of the Solitary Bees, explained.
In addition to the direct role in honey production, the bee is a biological indicator of the quality of the environment and currently represents one of the ongoing ecological emergencies. The largest producer of honey is Argentina which has reduced its 75,000 tons per year by 27%.
In Italy in 2007 50% of bees died, 200,000 beehives lost and 250 million euros in the agricultural sector. Bees die from various causes, not always fully identified: environmental causes, climate change, varroa and other natural antagonists, the indiscriminate use of pesticides.
The hives are depopulated due to the phenomenon of Colony Collapse Disorder. In various countries, phytosanitary regulations and authorizations for the use of pesticides have imposed restrictions on plant protection treatments for decades in order to protect the activity of bees and pollinating insects in general.
One of the most frequent constraints for many active ingredients is the prohibition of performing treatments, even if they are not insecticides, during flowering.