How much of a pesticide do you think it takes to cause harm? For insects, the amount to cause harm is even smaller than scientists could have ever hoped to imagine. New research has highlighted just how dangerous chemical pesticides really are, yet for some reason these literal poisons continue to sit on store shelves and are carelessly sprayed on yards and farms across the planet. In Germany, bug populations are experiencing a steep decline. The state of North Rhine-Westphalia has seen a devastating drop; insect populations have decreased by nearly 75 percent in just the last 25 years. How do you think the rest of the world is faring?
The harms of pesticides are nothing to sneeze at, though their manufacturers and other mainstream proponents would probably like for you to believe otherwise.
Chemical pesticides are, no doubt, the scourge of the earth. And as biologists from Bielefeld University have now shown, even the smallest amounts of pesticides can have a tremendous impact on insects.
One of the research team’s findings was that leaf beetles showed a dramatic drop in the number of eggs laid after coming into contact with a popular form of pesticides known as pyrethroids. On average, beetles laid 35 percent fewer eggs after being exposed to a pyrethroid. The team also found that female offspring developed malformations as a result of their parents’ exposure.
Germany’s mustard leaf beetles are a prime example of how chemical pesticides can interfere with nature in all the wrong ways. The beetles use a special chemical signature to find mates, and the Bielefeld team has found that pesticides can disrupt that. Dr. Thorben Müller, the study’s primary author, explains, “‘For the first time, we have been able to show that contact with pesticides changes this chemical signature on the body surface. As a consequence, beetles may fail to recognize suitable mating partners for reproduction. This alone may already reduce the number of offspring.”
Further, the impact of chemical pesticide exposure can effect future generations — even if they themselves never come into contact with a pesticide. “The offspring of beetles that have eaten leaves contaminated with pesticides develop more slowly than the offspring of beetles that have fed on untreated leaves,” says Dr. Müller. “Female leaf beetles whose parents had contact with such chemicals develop antennae of different length. This malformation can impair partner choice and the choice of egg laying places,” he added.
Research published earlier in 2017 also indicated that the harms of genetic pollution can extend for up to 14 generations past the point of exposure.
Past research has pointed to pesticides, in particular, as a vehicle for dangerous, multi-generational issues. Chemical pesticides have been linked to causing health problems in humans for up to three generations after initial exposure — what do you think they are doing to smaller, more delicate creatures?
As Dr. Caroline Müller, a professor and head of the Department of Chemical Ecology, notes, green leaf beetles are not the only insects that use chemical signatures to communicate. Bees and wasps use a similar method of communication, which suggests they too would be vulnerable to the pitfalls of pesticides. Certainly, the rapidly deteriorating bee populations ought to be indicative of that.
Clearly, pesticides are not doing the environment any favors. [Related: Learn more about the dangers of pesticides in all their forms at Pesticides.news.]
Sources for this article include: