Insect attack

As many of you may know, not all insects are bad. In fact, some are actually quite beneficial. The groups I’m referring to are predators and parasitoids. These kinds of insects help maintain population balance in natural ecosystems. In agricultural systems, they can help suppress and manage pest populations and prevent outbreaks.

Predators
Predatory insects are the carnivores of the insect world, feeding on other insects and animals. Common predators include ladybugs, hover flies, and mantises. Arachnids, like spiders, are also great predators. My current favorite are predacious diving beetles in the family Dytiscidae. Specifically, the pair of sunburst diving beetles Thermonectus marmoratus (order Coleoptera) I have swimming around in the tank on my desk.

Photo from Arthropoda

Parasitoids
In explaining parasitoids, I must also differentiate between parasites. So I’ll start with the latter. Parasites are organisms, in this case insects, that feed on other organisms and depend on them for survival. They complete their reproductive cycle on the host without killing it. Lice are parasites for example. Their host specificity can vary from humans, cows, or birds in some cases. In contrast, parasitoids feed on other organisms and complete their reproductive cycle while killing their host. Many parasitoids include wasps or flies. A majority of parasitoids have specific hosts but some are generalist parasitoids and can use different host species. Parasitoids lay their egg(s) in their host, and the immature parasitoids develop within the live host. As parasitoids continues to develop, it slowly kills the host.  For the record, it’s one of my pet peeves when the terms “parasite” and “parasitoid” are used interchangeably.  They’re similar, but really not the same.

Photo courtesy of University of Florida Entomology

This video was shown in one of my classes.  From National Geographic, it’s a clip about parasitic wasps called “Body Invaders.”  Fascinating, and a little gruesome.

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