Good Bugs, Bad Bugs?
"Don't touch it!! It's a BUG!!"
"It's a SPIDER, step on it!!"
All, most likely, common ways to react when a "bug" is encountered, particularly when the bug is in that most secure of our places - our home.
What is it about a bug that elicits such a response from people in many of the "advanced" cultures? Is it necessarily true that bugs are bad and should be avoided? Absolutely not! In fact, the majority of the bugs you may encounter in your yard, or even inside your home, are not going to cause any kind of a problem, and may actually be of benefit to you. Let's take a look at some.
In a natural environment, where humans have not imposed and introduced structures and landscapes filled with exotic, non-native plantings, all insects and other arthropods have activities that contribute to a relatively efficient environment. Changes happen continually as weather or other major influences affect the environment. The "Balance of Nature" took a pretty heavy blow in the 1970's, when Mount St. Helens erupted in Washington, but, ultimately, it may return to pretty much the same condition it was in prior to the explosion. In general however, all bugs help the flow. Even some of the peskiest of the "pests" - mosquitoes, fleas, ticks, and other disease carriers - probably are important in maintaining populations of animals at reasonable levels.
The scourge of our most beloved possession - our HOME - is the termite, and what bug could possibly be more deserving of the label "pest" than a termite? And yet, in nature, the role of the termite is critical, in recycling dead trees and other plant material, reducing a dead tree to sawdust and humus that are necessary for a forest to function properly.
So, while many of the bugs are "pests" when they interact with humans, there also are many that must be considered BENEFICIAL regardless of where they are. These are the many, many species that eat other pests, pollinate our flowers, aerate our soil, or work to decompose and recycle Nature's leftovers. While it is absolutely impossible to discuss and depict all of these in this short program, let's take a look at some of those that most commonly are encountered in our urban world.
Given enough time, everything in nature is recycled. Most obvious to humans, in our short 100-year life spans, is the decomposition of plant material. In fact, more and more we have learned to accelerate this process for our own uses, and we call this "composting". Nature excels at this but, perhaps, with a bit more patience. Let's look at the life (as it were) of a dead tree.
Trees die - bark beetles, drought, fire, old age, or a lightening strike if you live in northern Wisconsin. Immediately that tree sends out signals, new odors that signal to the decomposers that work is to be done. The first on the scene may be Long Horned Beetles or Wood Wasps, whose females lay eggs on the bark of the tree. The eggs hatch, and the larvae spend the next 1 to 10 years boring through and eating the solid wood. Finally, they pupate and then emerge as an adult insect, which may repeat the process until the wood is no longer suitable for their kind, and they move on to other, newer dead trees.
Unfortunately, on occasion the dead tree is cut down, milled, and used for lumber to build homes, with these recyclers already inside. When they emerge through the sheetrock and wall paper in your home it can be frightening and a concern. While it is an irritation having to fill the holes and repair this minor damage, the vast majority of the species that may appear like this are of no further danger to the home. They simply leave.
Once these first inhabitants have opened up the solid tree, the next wave enters - termites, carpenter ants - and the dead, still standing tree gets more and more hollowed out, and loses more of its ability to stay upright. Eventually, perhaps in a wild storm, the tree falls, and now, laying on the ground, it is accessible to many other insects that work their way in. It becomes wetter, and fungi feed on it. Small mammals may dig into it to create a home, bears tear it apart to eat the insects. Eventually, although it may have taken many decades, the once solid tree is a long line of sawdust, with new trees growing from it, thriving on the nutrition that was locked in the tree, and now has been returned to the soil.
All of the various insects that inhabited the tree, eating it and boring in it, were of benefit to the forest. Our problem, of course, is that they all may attempt to do the same thing to our home, and this is when we label them as pests.
Without a doubt, this is one of the best known examples of how insects benefit humans. With few exceptions, in order for a plant to produce a fruit, nut, or vegetable, pollination is required, and almost always is done by insects. There are some minor players here - ants, butterflies, beetles, and other bugs that may visit a flower and accidentally carry some of the pollen off with it.
However, the Queens of the Pollinating Industry are BEES. All kinds of Bees, as almost all species of bees do gather pollen as a food source for their larvae. Now, there are some REALLY pesky critters we lovingly call "Meat Bees", but in reality these are not bees, but are yellow jackets - wasps that are convinced that the picnic lunch you just set out was meant for them.
Why did I call the pollinators "Queens"? It simply is because the most obvious of the bees around our yards are "social" bees such as Honeybees and Bumblebees. These kinds maintain a very complex society, composed entirely of females, in which they care for their Queen, her eggs, and all the larvae. The female workers are adept at gathering pollen, packing it onto their hind legs, and creating "bee bread" for the larvae to feed on. In this process they transfer large amounts of pollen from one flower to another.
There are many other kinds of bees, most of them looking pretty "bee-like", but coming in sizes ranging from the tiny Mining Bees to the enormous Carpenter Bees. There are sweat bees, mason bees, cuckoo bees, digger bees, and the common and relatively harmless Leaf-Cutting Bees. These colorful little workaholics seek out little holes or crevices that are suitable for holding a cell the adult bees construct from pieces of green leaves. The use their jaws like scissors to cut off a large piece, roll it up with other pieces into a tube, and then pack the tube with pollen and an egg. Their larva lives inside the tube with all the comforts of home, finally emerging as a new adult months later.
Now, sure bees can sting, and there really isn't anything pleasant about the experience. But, given the benefit to be gained from the activity of bees, hopefully we all can forgive them for protecting their colonies or themselves in such a violent fashion.
Keeping the Soil Tilled
For those of you who have lived with the Red Imported Fire Ant, it must be hard to imagine that there is ANYTHING positive to say about it. In fact, given that it is a foreign invader in the United States, and has a huge negative impact on the natural environment it has invaded, ultimately it is not beneficial to us. However, ants in general are of tremendous benefit, and in tropical countries, such as those in the Amazon Rain Forest, it generally is conceded that ants are THE DOMINANT animal, and control much of what goes on there. From my numerous trips to South America, clearly the Army Ants and Bullet Ants are the animals you need to watch out for.
Most ants nest in the soil, and over time, as they create larger and deeper galleries, they bring huge amounts of soil to the surface and huge amounts of organic matter down into the ground - insects they prey on or plant materials they use for food. The leaf cutting ants are well-known for burying millions of tons of leaves in the soil, adding nutrients to the otherwise nutrient-poor soils of the rainforest.
Many other ants - Argentine Ants, Pavement Ants, Harvester Ants, Honey Ants - make their homes in the soil, turning over the dirt as they do so. Many bees and wasps do the same thing, and it is common to find little piles of dirt in your lawn one morning, the result of Digger Wasps, Sand Wasps, or Spider Wasps digging chambers in the soil, in which they deposit a paralyzed bug and one of their eggs, the larvae soon feeding on the food provided by Mom.
The Predators and Parasites
Finally, and those we may love the most, we come to the Bugs that Eat Bugs. These likely represent most of the insects and other bugs that we are familiar with as Beneficials, but I can guarantee you that there are hundreds of kinds that you see regularly and do not realize are your friends. There is no possible way to hit them all, but let's list a few of the ones that I see most commonly in and around homes.
~ SPIDERS ~
These marvelous animals are all predators. They all feed on meat, usually in the form of other arthropods but, sometimes, in the form of small rodents or birds that they are able to capture. These may be the enormous Bird Spiders in South America, Tarantulas that climb into the trees or crawl into rodent holes in the soil.
It is a fact that all spiders are venomous, but also a fact that very few are capable of biting or causing harm to humans. Really, the only species considered dangerous to people in the United States is the infamous Black Widow. Most other kinds can be enjoyed - with the appropriate caution. For example, Jumping Spiders are almost comical. They are small, colorful hunters that run around on your walls looking for bugs to eat. These are some of the most advanced of the spiders, and can see you pretty well from a few inches away. They will jump back and forth trying to avoid you if at all possible.
The Predators and Parasites
~ LADYBIRD BEETLES ~
Commonly called "Ladybugs" these popular beetles are sold in stores and used for bio-control programs on some very important agricultural pests. While we think of ladybugs as the common red ones with black spots, there actually are dozens of kinds, some black, some orange, some white. However, all are predators, feeding as adults and larvae on nasty plant pests such as aphids, mealybugs, and scale insects. Most people recognize the adults, but few people know what the larva looks like, and refer to it as that "tiny alligator" just before they smash it. These tiny alligators should be protected and cherished.
Other beetles also are common and of benefit to us, while posing no hazard whatsoever. For example, the Soldier Beetles (also called Leatherback) eat other insects. Ground Beetles are great predators, as are Rove Beetles, Water Scavenger Beetles, Checkered Beetles, Tiger Beetles, and others.
~ PRAYING MANTIDS ~
These popular insects are named due to the appearance they have of being in deep thought, or prayer. Actually, many predatory insects hold their front legs in a similar manner - called raptorial - as it is the most effective way for them to grab another bug and hold onto it while they consume it. As with the ladybird beetles, part of the life cycle of Praying Mantids may be seen often, but not recognized, and this is the egg cases. The female exudes the case onto a branch or fence rail, and it looks like a big blob of something that obviously ought to be disposed of. Learn to understand what the bug world offers, and you will enhance your environment because of it.
~ LACEWINGS AND SNAKEFLIES ~
These are somewhat related, and also feed heavily on plant pests such as aphids and scale insects. Once again, while you may recognize the adults, it is the larvae which are much maligned, and actually feared simply because they move around and are bugs. The larvae of the Green Lacewing is such a voracious predator that it is given the nickname "Aphid Lion". From my own experience a single one can clean the aphids off of a rosebud in about 30 minutes, as it pierces the aphid with its sickle-like jaws, lifts it off the plant, drains it of the tasty juices, and throws the carcass away so it won't be in the way while going after the next treat.
The Predators and Parasites
~ FLIES ~
And, finally, we come to the beneficial flies. Yes, believe it or not, even flies can be beneficial and, in fact, most kinds of flies probably are. We just have to have the opportunity to find out. There are parasitic flies like the Tachinid Flies and Bee Flies. There are predators like the Robber Flies and the larvae of the Horse Flies.
However, the ones we will look at here today are the "Syrphid" flies, also called Bee Flies (because they resemble bees and wasps), Hover Flies (because they fly much like hovering hummingbirds), and Flower Flies (because the adult flies visit flowers for the nectar).
These are tremendous mimics of stinging bees and wasps, and are apparently afforded some protection from their own enemies because of this. There are many, many kinds that are common to your backyard and it pays to recognize them, because their larvae are excellent predators of aphids. So, how do you tell a fly from a bee? Well, there are 2 easy ways:
- Flies have only 2 wings, while bees and wasps have 4 wings
- The antenna of a fly usually is very short and fat, while bees and wasps have long antennae
It is the larvae of the Syrphid Flies that does all the beneficial foraging on aphids, and yet it looks like a little caterpillar, and you might be tempted to kill it when you see it. However, having a few of these on your infested roses or trees is a good thing, and you can pretty much watch and enjoy.
So, we'll end it here, even though we have only skimmed the surface when it comes to touting the benefits of insects and other bugs. Hopefully the information we've provided will tempt you to get a simple, inexpensive Field Guide to the Insects, and begin learning about the critters you see in and around your home. If we develop a tolerance for the Good Guys it will make the garden a better place to be.
Please look for more of these short stories on Bugs, on Buginfo.com . We will be adding new articles on a regular basis, and hope that it becomes your means for acquiring ACCURATE information about the world of pests. Let us know what you think and what you'd like to hear about.