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box elder bug boom

Bebblog_1Large aggregations of insects — a crop of periodical cicadas, overwhelming hatches of mayflies, or the sudden synchronous appearance of many colonies of winged ants — are most often a summertime phenomena. But fall can be an excellent time to observe — even without intending to — equally impressive bunches of bugs.  Within the last few days in my region, the annual assemblege of Eastern Box Elder Bugs (Boisea trivittatus) has begun.

Despite the ubiquity of Box Elders (Acer negundo) around here, I don’t see boatloads of Box Elder Bugs most of the summer.  As the name suggests, they feed primarily on Box Elders, but will also utilize other maples. Box Elder Bugs (let’s call them BEBs) are Hemipterans, or true bugs, with piercing mouthparts. They suck juices from young leaves and stems, but really prefer the newly developing seeds of A. negundo. Since Box Elders are dioecious (male and female flowers are on separate trees), large populations of BEBs really only occur on female Box Elders, which have all the seeds. BEBs rarely do any damage to trees.

Beblight_2Mature BEBs are about 12 mm long. BEBs overwinter as full-grown adults, so now is the time of year when they begin looking for sheltered places in which to hibernate. First they gather en masse on or near tree trunks. Then they may fly up to two miles prospecting for a cozy, dry location to pass the winter months. In nature, rock piles or loose bark might do the trick, but buildings also offer excellent refugia.  BEBs wedge their way under shingles, into vents, and various other cracks and crevices. If it has been a warm, dry summer — like this one in the Midwest — there might be thousands of BEBs on the sunny sides of buildings, just taking a break from their search, or looking for entry into an appropriate hibernacula.  When they get into residential buildings, people get all freaked out, although they are completely harmless to humans.

Although I have an enormous geriatric female Box Elder in my yard, I have few BEBs, and none have ever sought sanctuary in my house.  They have, however, begun to accumulate on the outside walls of our campus parking structure.  Many will crawl under light fixtures and signs, to emerge on warm winter days to bask a little before retreating once again. On these brisk winter afternoons, I welcome the sight of these handsome little bugs, with their pleasing geometric pattern of black and red. Their tentative exploration of a January thaw provides a reminder of the richness and plenty of summer during a time of year when that fecundity seems furthest away. I like to think that perhaps, like me, they turn themselves to the winter sun, and imagine the lush abundance of a summer past, and one yet to come.

Filed in Insects, Natural history

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  • Kris October 5, 2005, 1:20 pm

    We have quite a few box elder bugs in our house, which afford no end of amusement to our younger cat, Sekhmet. We get them every autumn, and we don't mind them at all. We try to take them outdoors and we try not to let the cats mutilate them … not always easy. Sekhmet will sit and stare at one for a long time, moving to different vantage points, and then eventually she'll pounce (if we let her). But she seems more afraid of the bugs than anything!

  • TroutGrrrl October 5, 2005, 5:50 pm

    I was ruminating on a similar post – we are also experiencing a BEB boom, but there are a couple of other species booming with them. I think I should also tie in the ecological relationship with our cat population as Kris alluded to…

  • Pamela Martin October 5, 2005, 7:55 pm

    Three or four years ago we had an enormous number of these bugs in the house–too many to live with. For the last couple of years though our fall visitors have been millipedes. Interesting that you call this tree "box elder." I am familiar with this name for it, and "ash-leaved maple" as well, but I know it as the Manitoba maple. Only in Canada?

  • Nuthatch October 5, 2005, 8:49 pm

    I've also heard "ash-leaved maple", although only in books and reference material — virtually everybody here calls it box elder. And Manitoba maple…that must be Canadian, but I haven't even heard it in Windsor!

  • Clare October 5, 2005, 9:58 pm

    It is certainly called the Manitoba Maple back home in Manitoba. Can't remember the BEBs though

  • Nuthatch October 6, 2005, 6:26 am

    I can surely say I've never seen a reference where Boisea trivittatus is called the Manitoba Maple Bug!

  • Clare October 6, 2005, 7:53 am

    Yeah, but you've got to admit, it does have a nicer ring to it.

    Manitoba Maple Bug – MMB

  • Pamela Martin October 6, 2005, 10:39 am

    I just wish I could remember what the person who first named the bug for me called it. I think she did say "Manitoba maple bug," but I've been calling it the ash-leaved maple bug, because I've been using the name for the tree lately in an attempt to liberate it from its reputation as a "weed" tree. (It hasn't worked.)

  • beetlecat October 13, 2005, 12:23 pm

    Box elder bugs are swarming here in MI.

  • John October 2, 2006, 5:10 pm

    Hi All
    Manitoba Maple is the Tree and BoxElder Bug is the problem…How do we get rid of them???
    I can't even go onto my deck, they are everywhere, though not inside, as of yet.

  • Nuthatch October 2, 2006, 5:21 pm

    Not much you can do — sweep them off, blow them off with a leaf blower, or attract them to a nice place, such as a piece of plywood propped up fairly snugly against a south or west facing wall. They'll gather on and under that to keep warm and perhaps stay away from the house. They seem pretty numerous here this year, so it may have been a good year from them. But, they are harmless, don't bite or stink or anything.

  • Kelly Kasten April 9, 2008, 9:30 pm

    We live in Frankford,On. Canada. We just bought the house in Aug.07 for a steel…any wonder the people left…..these &*%$#%^..bugs drove them out!! Its now the beginning of spring after a long snowy winter and we already have them in multiples+++ IN our house. HELP!!!!!

  • Nuthatch April 10, 2008, 6:31 am

    I think this tells you that you have a "leaky" house with a number of places where the bugs can get in. Vacuum them out this spring, and over the summer get an energy audit; usually utility companies will do them for free or a small fee. In particular, an infared image of your house will show you where heat/cooling is escaping, and where to plug the gaps. That should help keep the bugs out in the future, and save you energy dollars as well.

  • David Farmer June 2, 2008, 11:24 pm

    I have lived in a house that had these bugs (and the tree next door) and man was that ever a nightmare. Pest control companies would not come out and spray because they knew that the problem would not go away until the tree was removed. We sprayed on our own but eventually the bugs just became immune to the pesticide. There were hoards of them everywhere inside and out. There was no relief until after the landlord struck a deal with the neighbor to have the boxelder tree cut down. It is as simple as this, if you have an infestation problem with these bugs you have to chop down the boxelder tree before it will get better.

  • Nuthatch June 4, 2008, 12:48 pm

    Yes, cutting down the tree will help. In fact, if you get rid of all trees, you also won't have a problem with noisy cicadas or kadydids, or birds making sounds or pooping on your property. Filling in wetlands will also reduce mosquito populations. My suggestion, however, is that if you don't want to be inconvenienced by the natural world, just move to a downtown area that is entirely concrete.

  • Angela August 26, 2009, 5:59 pm

    Hahaha… ever so entertaining… but anyways, please folks, let us respect nature as it is meant to be… just take to observing these insects with awe and amusement… don't let them bug you!!!

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