Last weekend I received a message from a friend about a cluster of Boxelder bugs hanging out in the flower bed next to the house.
Boxelder bugs range in size from half to three-quarters inch long. They are narrow-shaped, flat-backed and dark gray or dark brownish black. They have three highly visible orangish-red stripes running lengthwise on the pronotum, the area behind the head.
The bugs are seed-feeders and are so-named because of a strong association with the Boxelder tree. However, both the adults and nymphs will commonly use their piercing-sucking mouthparts to draw juices from the seeds of other trees in the Maple family.
They have also been observed feeding on alder, apple, buckeye, cactus, geranium, grape, honeysuckle, lilac, linden, oak, peach, plum, spirea and strawberries. In the past entire Boxelder trees were cut down in an attempt to eliminate the bugs. However, because of their wide-ranging feeding activity, this management effort often met with failure.
In the world of insects, a nymph is an immature form. Nymphs undergo gradual metamorphosis before reaching their adult stage. During gradual metamorphosis a nymph’s overall form resembles the adult except for a lack of wings. Some other insects that undergo gradual metamorphosis are praying mantis, grasshoppers, and dragonflies. Gradual metamorphosis undergoes three types of changes before they reach the adult stage. The stages are egg, nymph and adult.
As we head into autumn, temperatures will begin to drop. This will no doubt convince fall home- invading insects that it’s time to seek winter quarters. These unwelcomed guests, besides the Boxelder Bugs (Boisea trivittatus), include the Western Conifer Seed Bugs (Leptoglossus occidentalis); Multicolored Asian Lady Beetles (Harmonia axyridis); and the most notorious of all, Brown Marmorated Stink Bugs (Halyomorpha halys).
Insect fall home invaders do not intend to trespass inside homes and other structures. In fact, those that make their way into the interior spaces of homes are doomed. As with all insects, the survival of home invaders is governed by a “cold-blooded” physiology meaning the speed of their metabolism is mostly governed by ambient temperature. The higher the temperature, the faster their metabolism, and the faster they “burn” fat. Yes, insects have fat, but it is confined by their hard exoskeletons, so they do not suffer embarrassing expanding waistlines.
The home invaders feed voraciously in late summer to accumulate fat. They then seek sheltered locations in the fall where cool temperatures slow their metabolism during the winter so they will not exhaust their stored fat reserves. This survival strategy keeps them alive since there is nothing for them to eat throughout the winter.
The insects are attracted to the solar heat radiating from southern or western facing roofs and outside walls of homes, as well as the warmth radiating from within. This can lead them into attics, exterior wall voids, and spaces around door jams and window frames. These all make perfect overwintering sites, and they stand a good chance of surviving the winter if they remain in these cool, protected locations.
However, they sometimes make a terrible error, for both the insect and the homeowner. Instead of staying put, they continue to follow the heat source and enter homes. This is accidental and disastrous for the insects because the high indoor temperatures cause them to burn through their fat reserves and starve to death.
The best defense against home invaders found inside a home is to prevent them from entering in the first place. An ounce of calking is worth a pound of bugs. Large openings created by the loss of old caulking around window frames or door jams provide easy access into homes. Such openings should be sealed using a good quality, flexible caulk or insulating foam sealant for larger openings.
Poorly attached home siding and rips in window screens also provide an open invitation. The same is true of worn-out exterior door sweeps including doors leading into attached garages. Both lady beetles and stink bugs commonly crawl upwards when they land on outside walls; gaps created by loose-fitting soffits are gateways into home attics.
Insects that find their way into a home should be dealt with carefully. Swatting, or otherwise smashing these insects, can cause more damage than leaving them alone since fluids inside their bodies can leave permanent stains. Also, mashing multicolored Asian lady beetles and brown marmorated stink bugs can release lingering eau de bug; lady beetles have stinky blood and stink bugs are called stink bugs for a reason.
The best way to remove these invaders is to use a dustpan and broom. Gently sweep up the insects and dump outside, preferably away from the home. Try not to use vacuum cleaners and shop vacs as they present their own sets of risks. If used on stink bugs and lady beetles, these insects will release their defense odor in response to swirling around inside the vacuum tank. This will also give you the lingering eau de bug scent.