As I headed out to feed the chickens and harvest eggs, something caught my eye on the metal siding beside the door. It was a shady spot, as the door faces north. There was a large buff-colored praying mantis, moving ever so slightly. Because it was in the shade and autumn temperatures were in full effect, very slow movement was to be expected.
The mantis, after all, is cold-blooded (beyond the sense of its hunting habits), with no internal mechanism to maintain temperature at a certain metabolic rate. Whatever the outside temps are, the core heat of the insect will land in the same place without an external source of warmth. Yes, the mantis was at the end of its life, and the cold on its way would assure that. Nonetheless, I scooped it up and moved it to a sunny spot on a hollyhock spike. There, it would have couple more hours of heat, and perhaps would find some shelter before the sun set.
Perhaps you’ve asked yourself: what happens to insects through the winter and why don’t we ever have a shortage of bugs, friendly and not, in the spring, after very harsh winter conditions?
It’s common knowledge that insects live for a relatively short time. Some live longer than others — surprisingly so. For instance, cicadas live for around 17 years, almost all of it underground, in the nymph stage. The longest-living insect is believed to be the queen termite, which can live for decades. The queen honey bee can live for about five years, but produces the majority of her eggs within three years or even earlier. There are other examples of overwintering or multi-season insects, but for the most part, winter decimates the insect population you saw in your garden late in the summer and into the fall. So then, how does the species continue to flourish?
There are various coping mechanisms insects have, including a form of hibernation. Most insects change form throughout their development, so while the adult form may not overwinter, a different development stage in the insect’s species may be especially equipped to remain viable during very cold conditions.
That mantis I saw? While she herself won’t survive winter, her offspring most likely will. The mantis’ egg case is a familiar sight to most of us. It’s a tan, foam-like case you’ll find stuck to the sides of buildings and under ledges. The eggs in that case will remain dormant until warm weather returns. When they hatch, the mantis’ cycle of life begins all over again. While the adult form of the mantis can’t overwinter, the egg form can, and does, quite dependably.
The trait of going through stages of insect development, called metamorphosis, is what actually gives most insects the ability to continue the next generation. Depending on the insect, they can be found in egg, larvae, pupal, nymph or adult stages. Every insect does not go through all of these stages. Some species, such as grasshoppers, look essentially the same as juveniles as they will as adults, but are simply smaller. To reach adulthood, they have to create a new exoskeleton several times through the process of molting. Between each molting, they are instars. I’m not making this up, even if the term sounds like something from Star Trek.
There are other insects, besides grasshoppers, that change very little in form as they grow from young to adult size. This process is called simple metamorphosis. The young insects are called nymphs, and usually live in that same setting and eat the same thing as their adult counterparts. Nymphs are not sexually mature, nor do they have wings. Aphids, mites and squash bugs are a good example of the type of insects that reach adulthood through simple metamorphosis.
There are also insects that develop through complete metamorphosis. These types have young and adults that look very different from each other. In fact, they may live in different habitats as well. After hatching from eggs, the young become larvae. Most larvae possess food with chewing mouthparts, even though the adult form later may have sucking mouthparts that allow it to pierce the skin of a plant and extract juices. The larva will develop through several stages before transforming into a pupa and ultimately an adult. The pupa is usually inactive and doesn’t even eat. For many insects, it is in the pupal stage, when the insect is most dormant, that overwintering occurs before emerging as adults. Butterflies and moths are the most common examples of this.
Now that you’ve had a quick romp through some botany, zoology and biology, let’s look at some common insect citizens in our area and see how they will make it through the winter that is quickly approaching.
Squash bugs are prolific in our area, and are especially damaging to young squash-family plants. Many a gardener has experienced both zucchini and summer squash plants under attack. But, where do they come from? As the cold weather approaches, any nymphs (non-adults) that remain die. They are not winter-hardy. As any gardener that has done battle with squash bugs knows, the nymphs are much easier to control with pesticides than the adults.
The same goes for cold weather. Unmated adults seek shelter in the form of debris, dirt clods, wood and brick piles, and even adjacent buildings as the cold comes on. In spring, both sexes fly to new squash plantings or emerging seedlings, to feed and mate. Eggs are laid almost immediately and begin hatching about 10 days later. It takes four to six weeks for adulthood to be attained, and requires a lot of feeding (and resulting damage) along the way.
Knowing the squash bug’s habits and needs tells us a lot about how to control them. First, eliminate as many overwintering places as possible. All dead plants and leaves need to be raked off. Then, practice good rotation schedules. Emerging adults won’t have a nearby feeding and mating site. Why make it easy for them? Use pesticides early on, and under the leaves, as the nymphs are more easily controlled than adults. To control adults, put pieces of cardboard or flat boards down for them to hide under overnight. Collect them in the morning and dump them in a bucket of soapy water.
Aphids have another approach. They typically overwinter as eggs. As spring returns, they hatch and rapidly reproduce. Aphids generally produce multiple generations in a season. They are soft-bodied, and food for many other insect and bird species. Their most successful methods of species survival is producing astronomical amounts of offspring in a short period of time, once a ready and plentiful food supply is colonized. To control the overwintering population, horticultural oils may be used. This helps to smother the eggs and if applied early enough, denies access to hiding places for them to lay eggs in.
Aphids that are on plant surfaces during the growing season are effectively controlled using a soapy mixture both to rinse off the offenders and also to do them in. Their soft bodies, and the membranes that comprise them, cannot stand up to soapy water. Soap makes water “wetter” by reducing surface tension and allowing moisture to enter the aphid’s bodies. I like to imagine it’s somewhat like popping thousands of little-bitty water balloons, but that’s just my overactive imagination and desire to get even.
Bees, wasps and bumble bees all have methods of overwintering. Next week, we’ll delve into the fascinating world of the honey bee and how they thrive over the winter. Most honey bee colonies are maintained hives, although there are some wild colonies found in hollow trees, crevices in rock faces, abandoned buildings, and in some cases, cavities in occupied structures.
The Tooele County Beekeepers had a meeting last week in which we discussed practices to assure that our bee colonies survive the winter and have a strong start in the spring. Honeybees are social creatures that maintain a colony from year to year. Technically, a colony can live for many, many years, although any single bee will only live for a short time. But, I’m getting ahead of myself.
Be sure to “tune in” again next week, and I’ll pull back the curtain a bit on the mesmerizing world of beekeeping. Heck, who knows? Beekeeping may be in your future. I’m already looking forward to next spring and the summer crop of honey to come.
Jay Cooper can be contacted at firstname.lastname@example.org, or you can visit his channel at youtube.com/dirtfarmerjay for videos on the hands-on life of gardening, shop and home skills, culinary arts and landscaping.