For several years the BugLady has been photographing this nifty little bug at the edges of Riveredge prairies. She figured it was one of the (many) mirid plant bugs, but it’s been uninviting outside lately – damp and cloudy, with a chance of slush – so she applied herself and decided on the Clouded plant bug (Neurocolpus nubilus) (probably).
Miridae is a large family in the “true bug” order Hemiptera. If you have an older insect field guide, Miridae is part of the former order Homoptera, which has been folded into Hemiptera. With more than 10,000 species overall (about one-fifth of them in North America), mirids are the largest family of Hemipterans. Many mirids are plant eaters, and some are unwelcome in gardens and agricultural fields, but Tarnished plant bugs are singlehandedly responsible for much of the family’s bad reputation https://bugguide.net/node/view/1494218.
Like all “true bugs,” a mirid’s mouthparts are adapted for piercing its food source (be it animal or vegetable) and sucking the fluids from it (the mouthparts are tucked along its underside when not in use, which can be seen in one of the BugLady’s pictures). Its wings are membranous at the tips and more leathery where they attach to the body (Hemiptera means “half wings”). A small downward “fold” of the wings toward the bug’s posterior is a mirid field mark.
Clouded plant bugs resemble many other mirids in that they are small, angular, and cryptically colored in various shades of brown (there are some spectacular mirids, though: https://bugguide.net/node/view/1672242/bgimage, https://bugguide.net/node/view/284743/bgimage, https://bugguide.net/node/view/1016022/bgpage, https://bugguide.net/node/view/506088/bgpage, https://bugguide.net/node/view/399110/bgpage, https://bugguide.net/node/view/1294241/bgpage, and https://bugguide.net/node/view/1060593/bgimage).
The Clouded plant bug is found in the eastern and mid-western parts of North America, and Americaninsects.net describes it as “widespread, but not always common.” Of the 14 species in the genus, some are nearly identical and could be a “species complex,” a slippery assemblage of very similar-looking, closely-related species that may or may not be able to interbreed successfully and that confuse biologists (but not each other – they know who they are). Neurocolpus are less than ½” long, adults and nymphs have a swollen, bristly segment at the base of each antenna (https://bugguide.net/node/view/96507/bgpage), and they have heavy “thighs” on their third set of legs, which the BugLady didn’t even notice because she was so enthralled with the front end of the bug. Nymphs are greenish, and their antennae are red-and-white striped https://bugguide.net/node/view/192135.
Both the adults and the flightless nymphs are generalist feeders, and the list of plants that they’ve been seen on has more than 40 species on it, both woody and herbaceous (mints are near the top, along with composites and a variety of bedding and perennial plants). Cotton is on that list, too, and Clouded plant bugs are considered minor cotton pests that may be increasing as insecticide regimes have changed. Their feeding causes round spots of dead tissue on leaves, and in cotton, the shedding of small buds, but their populations peak too late in the growing season to have a big impact on cotton yields.
Along with camouflage, lots of mirid species dodge predators by secreting nasty chemicals through pores in their sides, but this doesn’t always deter hungry birds, spiders, and insects. Adults are quick to take flight, and nymphs dash around to the opposite side of a twig or under a leaf when danger threatens.
Females lay eggs deep in plant tissue. There are several generations each year in middle and southern states, and the final generation overwinters in the egg stage. Look for them here throughout the summer.
Kate Redmond, The BugLady
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