Insect Facts: 3 Reasons We Need Them
Most of us aren't crazy about insects. They're creepy and crawly, and we usually only think about them when they're bugging us. But while we're not paying attention, they're doing lots of work to keep our natural world functioning. Read on, and you'll learn about some insects, both familiar and unfamiliar, that are surprisingly important.
Many insects work hard at pollinating our plants. The honeybee may get all the publicity, but in some cases, other insects do an even better job.
There are flies that pollinate apples, peppers, mangoes and cashews. Many beetles are also important pollinators. And there's one major crop that's pollinated by tiny midges — one that many of us might find particularly important: cacao. The cocoa beans from inside the pods of these trees are refined into chocolate.
Although honeybees are significant because of the wide variety of foodstuffs they pollinate, other pollinators are important because they're specially adapted to specific plants. In fact, the honeybee, which is an introduced species (non-native to North America), isn't as good at pollinating native North American plants as the species of bee that evolved along with them. Tomatoes, for instance, only release their pollen if the flowers are vibrated in a certain way. Honeybees don't know how to do this, but native bees do.
And what about plants that bloom at night when bees are asleep? Flowers like the evening primrose and night-blooming jasmine rely on moths. In fact, one of our native moths is another of those highly specialized pollinators: The yucca plant relies on the yucca moth for its survival. These plants are so specifically adapted that there's more than one species of yucca, each with its own species of pollinating moth.
The female yucca moth has specially evolved mouthparts that allow her to gather pollen from a yucca flower, form it into a ball and stuff it into the center of another yucca flower. If no insect knew how to do this, the yucca wouldn't develop seeds and wouldn't be able to reproduce.
Without insects, the world would be knee-deep in all kinds of refuse. Lots of stuff that you might think just rots away is actually cleaned up by insects.
You've probably heard of dung beetles — you know, those huge bugs in Africa that roll elephant dung into balls. But you might not know that we have them here, too. "We've got dozens of species of dung beetles right here in Maryland that are out working busily every day," says Michael J. Raupp, Ph.D., professor of entomology at the University of Maryland and Bug of the Week blogger.
They're not huge like the African ones — after all, without elephants and rhinos, we don't have such enormous piles of dung to deal with. But perhaps surprisingly for a creature that finds poop tasty and a comfy place to raise a family, some of these beetles are quite beautiful. And they certainly make the world more beautiful.
There are also insects that are crucial for getting rid of dead wood, a job that microbes can't do alone. Bess beetles have strong jaws to gnaw through wood and can digest it into droppings that they feed to their young. They'll only use wood that has started to decay, so they're no danger to your house.
And, of course, there's another sort of dead stuff that nature needs to clean up, and insects play an important role here as well.
People may think that when a deer gets hit on a highway, Dr. Raupp says, "there's a little bunch of leprechauns that come out in the nighttime and cart it away."
If transportation authorities don't get to the animal first, it's not just bacteria that decompose a dead critter. It's eaten by the young of many kinds of flies, such as blowflies and flesh flies.
"These maggots are recycling this animal protein and returning it to the ecosystem," Dr. Raupp says. "On all fronts, insects play this vital role in terms of recycling animal and plant waste materials."
Predators and Prey
Some insects get rid of pests that wreak havoc on crops and other plants.
Ladybugs are one of the few insects people have fond feelings about, because they're so pretty. But behind that compelling exterior lies a mighty hunter. As both larvae and adults, ladybugs are meat eaters, and while satisfying their hunger, they're doing us a favor, too.
"They're ubiquitous, voracious predators that are major factors in regulating populations of pest insects like aphids, scale insects and spider mites," Dr. Raupp says.
We talk about ladybugs as if there's just one kind, but there are actually more than 450 species of ladybugs (or lady beetles) in North America. A couple of them are introduced species that cause trouble by feeding on plants and getting into homes, but most of them help get rid of other insects that we can do without.
In fact, one of their favorite meals is another insect that's important for how much trouble it makes. Aphids are tiny, but that doesn't stop them from being a huge bother.
"Aphids are major pests of many vegetable crops," Dr. Raupp says. "They suck the plant juice out and weaken it by removing the products of photosynthesis. They're also very common on ornamental plants — they're all over roses in the springtime and make shade trees drip with their sticky excretion called honeydew."
A ladybug may eat as many as a thousand aphids during its larval development and then several hundred more while it's an adult as it produces its eggs, he says.
So be thankful for ladybugs, not just for how pretty they are, but also for their appetite for these pesky little critters.