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Beneficial Insects

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The only good bug is a dead bug, right? Although most people feel this way, less than 1% of all insect species are pests. Most of these bugs are outside, minding their own business, and doing what bugs do.  A lot of the time what they do is very useful for us. Even pest insects can be beneficial, but for safety concerns or aesthetic reasons they are not welcome around the home. Paper wasps, for example, will keep your vegetable garden caterpillar-free, while mud daubers spend most of their waking hours capturing spiders for their hungry young (and most people wouldn’t argue over fewer spiders).

In a world without humans, there would be no pests - “pest” is a human concept. I’m not downplaying the importance of these pest species. They cause all sort of problems for us: life-threatening allergic reactions, catastrophic property damage, disfiguring and debilitating diseases, and contamination and loss of food, just to name a few. There are many insects out there doing us a whole lot of good, so I thought we’d take a minute to discuss and appreciate them.

We all know that pollinators are beneficial. Pollinators are not just bees, but also butterflies, moths, wasps, beetles, and flies. Together, they help our food crops grow, they propagate the wildflowers that fill the fields, and some provide us with honey. They’re the reason we have chocolate, melons, cashews, apricots, and raspberries! Although some pollinators can sting – bees and wasps, primarily – their services outweigh their potential for harm, and most people will tell you that they care about pollinators to some degree.

Most people also consider praying mantises and ladybugs to be beneficial insects. They are, but their services can be a double-edged sword. Mantises will capture and eat pest insects, like house flies and paper wasps, but they are indiscriminate killers. Butterflies and honey bees are also on the menu. In fact, pretty much anything that isn’t toxic is on the menu. Large mantises, like the Chinese mantis, have been known to capture and eat small snakes… as well as hummingbirds.

The invasive multi-colored Asian lady beetle is a voracious hunter of aphids and other plant-damaging insects. The larvae and adult beetles both consume large quantities of small plant pests. Their downside is that the adult beetle is a home-invading pest. They often take refuge in houses by the thousands when the weather begins to cool. And if they die in our houses, they become a breeding source for carpet beetles, another household pest. Our native ladybugs, however, do not typically overwinter in houses, which makes them more of a truly beneficial bug. Most people wouldn’t call mantises and ladybugs “repulsive” or “gross.” Their presence is often a welcome sight in the wild, and most people appreciate catching a glimpse of these creatures in their yards and gardens.

Lacewing larvae provide services similar to ladybugs but without the nuisance of flocking to your house by the droves to spend the winter. The larvae, called aphidlions, look somewhat like a tiny alligator with long, curved mandibles. The larvae of some species will camouflage themselves by piling debris and the carcasses of their prey on their back – these are called trashbugs or junkbugs. If you’ve ever seen a slow-moving clump of dirt and fuzz, then you’ve probably seen a trashbug.

The adult lacewing is green or brown with delicate wings held over the body like an A-frame home. The complex network of veins on the wing gives rise to their common name – the lacewing. Green lacewings in particular have beautiful, iridescent eyes, and many macro photographers focus on this feature – just search online for “green lacewing eyes” to see for yourself. Lacewings are attracted to porch lights at night and can sometimes make their way inside, but they are completely harmless to humans. They cannot bite, nor do they attempt to, and they are weak fliers that can barely outfly a swatting hand.

Some insects bring us joy by simply existing (fireflies and butterflies). Others intrigue us with their hunting prowess (mantises) or display of physical power (ants carrying prey much bigger than themselves and stag beetles with their mighty mandibles). Many are beautiful (butterflies, ladybugs, and dragonflies), but most are useful in some way (pollination, pest control, and decomposition). The next time you see bugs outside, I hope you will remember that not every bug is a bad bug.