Autumn is here, and with it the longer evenings and cooler air. The shield bugs are looking for somewhere to hibernate. I spent some time last evening switching them off the outside walls of the house with a twig broom. Otherwise they crawl inside, squeezing in through the window frames. Once inside, they do no harm. But they are annoying, insinuating themselves into the bedroom and living room, buzzing clumsily around the lights, crash-landing into your hair, your drink, your soup… If you brush one with your hand, it will open its stink gland and release a malodorous pong. Hence their other name: stink bug. On the Patch we have three types:
1: Western Conifer Seed Bug (Leptoglossus occidentalis). Up until about two years ago this was the only stink bug visitor. Entomologically it isn’t actually a stink bug, but when disturbed it behaves like one. In appearance it’s long and elongated, prone to losing legs (as the example in the photo). Temperamentally it is mild-mannered and unaggressive. It’s very slow-moving. They spend the mild days of summer in the Douglas firs outside the house, feeding up on the seeds. In autumn when the temperatures drop, they crawl indoors. They’re difficult to deter, especially if you live in an old house with less than weatherproof window frames. Native to the USA, they have been in Europe for 20 years or so. Populations seem to fluctuate. In 2015 we had none at all. This year, 2016, we are host to dozens of them.
2: Mottled Shield Bug (Rhaphigaster nebulosa). This is a true shield bug. They also feed mainly off trees (but not conifers) and are native to Europe. The name means ‘Cloudy rod-belly’. If you turn them over, you will see a long sort of spike between the legs. They are a nuisance, coming indoors in quite large numbers and crashing clumsily around the living room when they take flight.
3: Brown Marmorated Stink Bug (Halyomorpha halys). This is the dreaded BMSB, an invasive species, native to China and Japan, which has turned into a serious pest in the US, devastating crops of maize, tomatoes and soya beans. Its first confirmed sighting in Hungary (where I found the specimen pictured below) was in the autumn of 2013. The photograph is blurry but the diagnostic features can clearly be seen: the necklace of dots at the base of the head; the stippled legs; the distinct pattern of tooth-shaped white marks along the sides of the wing case (the European stink bug has
white and black markings too, but they are differently shaped, and it lacks the dots across its neck and shoulders).
BMSB is more or less omnivorous. It will eat tomatoes, apples, sunflowers, grapes, pears, peaches, cherries, aubergines, figs… There is a website dedicated to understanding and managing BMSB in the US. Its natural predator, a kind of wasp, has not yet made the journey from Southeast Asia. Does that mean I need to kill all the BMSBs I find? Perhaps not. This article on Entomology Today suggests that katydids eat their eggs. I have plenty of katydids on the Patch.