Wooly bear caterpillars are tiger moths in the family Erebidae and in the subfamily Arctiinae.\u00a0It\u2019s a diverse family that includes almost a thousand\u00a0species\u00a0of tiger, underwing, Zale, tussock moths, and more,\u00a0in North America,\u00a0and many more worldwide (except Antarctica).\u00a0If you have an older insect guide, tiger moths are in the family Arctiidae, but everything that was once in Arctiidae has been folded into Arctiinae. Tiger moths are unusual in that they have an organ on their thorax that vibrates to produce ultrasonic sound.\u00a0They \u201cvocalize\u201d to attract mates and to defend against predators. If you have sound-making ability, you also need \u201cears,\u201d and those are on the thorax, too.\u00a0Like tigers, the adults of many species are hairy and sport bold color patches, stripes or patterns.\u00a0<\/p>\n\n\n\n Many tiger moth caterpillars are fuzzy, earning a group name of wooly bears or wooly worms (two \u201clls\u201d or one \u201cl\u201d – take your pick.\u00a0Two lls is more common in Britain and one l is more common here). The wooly bear\u00a0du jour<\/em>\u00a0is the ultra-familiar rust-and-black-banded caterpillar whose grown-up name is Isabella Tiger Moth (Pyrrharctia isabella<\/em>)<\/a>. The caterpillar goes by the generic Wooly Bear, and also Black-ended Bear, and the Banded Wooly Bear.\u00a0Pyrrharctia<\/em>\u00a0is a \u201cmonotypic genus\u201d \u2013 there\u2019s only this single species in it, and they\u2019re only found in North America. There is an amazing amount of information out there about wooly bear caterpillars, and much of it is contradictory, a problem that is exacerbated by the fact that there are many different kinds of caterpillars that are called wooly bears.\u00a0<\/p>\n\n\n\n A mature female Isabella Tiger Moth \u201ccalls\u201d to males by emitting pheromones (chemical signals) at night, and the males zero in on her by using their sensory antennae. Isabella Tiger Moths lay their eggs on a wide variety of plants during the warm months.\u00a0While some caterpillars are known for their picky eating, wooly bears are generalists.\u00a0They feed during the day, munching on handy, low-growing plants like grasses, \u201cweeds\u201d and wildflowers (cannibalism has also been reported).\u00a0Their catholic eating habits ensure that they\u2019re constantly surrounded by food during their autumnal wandering in search of wintering sites. \u00a0<\/p>\n\n\n\n Wooly bears spend the winter as caterpillars, out of the weather under tree bark or debris, or in your garage. Do they become \u201cbug-cicles\u201d?\u00a0Yes, indeed \u2013 they\u2019ve even been found frozen in a chunk of ice.\u00a0But, like other organisms that are dormant in the dead of winter, wooly bears produce a chemical called a\u00a0cryoprotectant<\/em>\u00a0(antifreeze) that protects living tissue against damage from freezing and thawing. Wooly bears will stir and walk around on mild winter days and then go back into hiding when the temperatures drop again.\u00a0They wake up with the warm weather, resume eating, and pupate in late spring in a fuzzy cocoon into which they incorporate their own \u201csetae\u201d (hairs)<\/a>.\u00a0According to\u00a0Wikipedia<\/em>, Arctic summers are so short that wooly bears may need to live through several of them to become mature enough to pupate.\u00a0 \u00a0<\/p>\n\n\n\n One area of disagreement among references is whether the wooly bears\u2019 wool\/setae\/hairs\/bristles are irritants.\u00a0Having a bristly covering discourages some predators, although in the\u00a0Fieldbook of Natural History, E. L. Palmer says that \u201cskunks and a few other animals roll hairs off the caterpillars before they eat them<\/em>.\u201d\u00a0Certainly, the stiff hairs make it a harder to pick a wooly bear up, and when you do pick one up and it inevitably curls into a defensive ball, it\u2019s pretty slippery.\u00a0Some sources say that the wooly bears\u2019 setae contain a stinging\/irritating\/venomous chemical, and other sources specifically say they do not.\u00a0Still other references say the setae may cause dermatitis mechanically \u2013 that they might break off in your skin (like one of those wretched, furry cacti); and others say that that unlike many hairy caterpillars, wooly bears are harmless.\u00a0The BugLady has never suffered any ill effects from handling the familiar, rust-and-black wooly bears.<\/p>\n\n\n\n Wooly bears have been famous since Colonial times for two things: 1) their habit of crossing the roads in fall (the BugLady wonders what they crossed before the Colonists arrived and started making roads); and 2) their alleged ability to predict the weather. <\/p>\n\n\n\n The weather lore angle was initiated by those same, road-building Colonists, who needed some forecasting done in those pre-Weather Channel days so they could figure out when to plant and harvest crops.\u00a0If its rust-colored middle band is wide, says the\u00a0Almanac<\/em>, the winter will be a mild one; if there\u2019s lots of black, batten down the hatches (except for a few sources that say the opposite – that lots of rust means lots of cold).<\/p>\n\n\n\n A surprising number of scientists have felt obligated to leap in and deflate the weather story. To them the BugLady says \u201cLighten up, Party Poopers, and let a little fantasy into your lives<\/em>.\u201d They tell us that the widening middle band is a result of age, and that each time wooly bears molt, a black band becomes a rust band (except for a few who say the opposite \u2013 that rust turns to black). So, a rustier wooly bear is an older wooly bear.\u00a0The BugLady has been curious about why the early fall wooly bears seemed more pessimistic than the later fall wooly bears and is happy to have that one resolved. In spring, a blacker wooly bear is one that became dormant prematurely, and may indeed be telling the weather \u2013 of the previous fall.\u00a0Other research suggests that a wooly bear with lots of rust lived in dry conditions, and one source says that a wooly bear with wide black bands grew up where the habitat was wetter.\u00a0Still other scientists say that there is considerable variation in color within newly-hatched individuals from a single clutch of eggs, and that the variation persists as they age.<\/p>\n\n\n\n We have Dr. Curran, a curator of insects at the American Museum of Natural History, to thank for popularizing the wooly bear. Charmed by the old weather saying, Dr. Curran drove north from New York City along the Hudson to Bear Mountain State Park each year for eight years in the late 1940\u2019s and early 1950\u2019s to measure the coloration of the wooly bears he found there. During those years, the rusty bands predicted mild winters. He leaked the forecasts via a friend at a NYC newspaper, and the publicity his reports generated put wooly bears on the map.\u00a0But Dr. Curran\u2019s only real hypothesis was that Scientists Just Want to Have Fun.\u00a0He and his friends enjoyed the scenery, the foliage and the wooly bears on their annual fall forays and formed \u201cThe Original Society of the Friends of the Woolly Bear<\/em>.\u201d Thirty years after Dr. Curran\u2019s outings ceased, the folks at Bear Mountain State Park resurrected the Friends organization and the wooly bear count.<\/p>\n\n\n\n Wooly bears are embraced by children and adults alike, and Annual Wooly Bear Festivals are celebrated:<\/p>\n\n\n\n Clearly, Wisconsin is missing the boat, here (though Milwaukee had a third annual Wooly Bear Fest in January of 2015). <\/p>\n\n\n\n Go outside \u2013 chart wooly bears. <\/p>\n\n\n\n The BugLady<\/em><\/p>\n","protected":false},"excerpt":{"rendered":" Greetings, BugFans, The BugLady has been doing a little dance as she walks down the trail lately, trying to avoid stepping on wooly bear caterpillars (her mission statement, after all, is \u201cLess stepping on bugs\u201d).\u00a0She has been less successful when …<\/p>\n","protected":false},"author":32664,"featured_media":15382,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":"","uwm_wg_additional_authors":[]},"categories":[8],"tags":[],"class_list":["post-15381","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-bug-of-the-week"],"yoast_head":"\n![\"moth](\"https:\/\/uwm.edu\/field-station\/wp-content\/uploads\/sites\/380\/2024\/10\/Isabella-tiger-moth08-1.jpg\")
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