Many insect species are declining in abundance and diversity because of pollutants including pesticides, heavy metals and airborne particulate matter. The sources of these environmental pollutants and exposure pathways are summarised in the graphic below. These pollutants can increase the disease susceptibility of social insects, by impacting their physiology, especially their immune systems.
In their review paper, Feldhaar and Otti provide an overview of the current knowledge about how these pollutants affect physiology and the interactive effects with pathogens and parasites. Although the effects of pesticide exposure have been relatively well studied, the effects of other pollutants including particulate matter are still largely unknown.
Sources of the environmental pollutants and exposure pathways of social insects to pollutants. Pesticides (including insecticides) derive mostly from agricultural sources, while heavy metals are released into the environment through industrial processes, combustion, or traffic. Fine particulate matter includes both, pesticides (or their residues) and heavy metals bound to particles of 10 µm and smaller. Fine particulate matter is composed of many different potentially toxic chemical components. Social insects can take up pollutants orally during foraging and then transfer them to the brood or incorporate them into nest material. In bees, pollutants can also end up in stored food, such as honey or bee bread. In addition, pollutants may be deposited on the cuticles of insects and their nests directly via the air. Subsequently, these may again be incorporated into nest material or even enter the insect’s body, e.g., via the tracheal system.
Copyright: Authors: Feldhaar, H. & Otti, O. Publication: Insects. Date: March 2020.
Licensed under CC BY 4.0 https://creativecommons.org/licenses/by/4.0/
Source: Figure 1 https://doi.org/10.3390/insects11030153
Read the full paper:
Feldhaar, H. & Otti, O. (2020) Pollutants and Their Interaction with Diseases of Social Hymenoptera. Insects, 11(3), 153; https://doi.org/10.3390/insects11030153