Some of our most un-bug-like bugs are the scale insects. There are lots of them worldwide \u2013 about 8,400 species in 36 families.\u00a0They\u2019re called scales because they (the females, anyway) cling, limpet-like, to their food plant, protected under a waxy covering that looks fish-scale-ish. They\u2019re sexually dimorphic (\u201ctwo forms<\/em>\u201d), and adult males \u2013 in the species where males exist – are often tiny and gnat-like.\u00a0If your basic definition of an insect is \u201csix legs, some wings, and three body parts that are divided in segments<\/em>\u201d you\u2019ll have to suspend it a bit for the scales.\u00a0<\/p>\n\n\n\n Their nearest relatives are aphids, whiteflies, jumping plant lice, and phylloxera<\/em> bugs.<\/p>\n\n\n\n They hatch from eggs that the female lays under her body (or they are viviparous – popped out \u201clive\u201d), sometimes fertilized with the help of a male and sometimes produced by parthenogenesis (\u201cvirgin birth\u201d), and a very few species are hermaphroditic (they have dual equipment and can self-fertilize, and so a single individual can create a whole population).\u00a0Six-legged when they hatch, scales enjoy two short, mobile instars (they\u2019re called \u201ccrawlers\u201d), during which they disperse, but their legs are short, so they don\u2019t go far without help (crawlers may also be blown around by the wind).\u00a0Then the tiny females settle down, attach to a host, and lose their legs, generally staying put for the rest of their lives.\u00a0The short-lived males must find females where they sit, and although he may be winged, his wings are not good for much, so he comes on foot.\u00a0There are generally several generations per year.<\/p>\n\n\n\n Scales are vegetarians, feeding on plant sap that they suck from leaves or branches.\u00a0Some are found only on specific hosts and others are more generalist feeders, and although a very few species feed on mosses, lichens, and algae, as a group, they\u2019re fond of the woody plants. Their predators include some ladybugs and lacewings, and a few parasitoid wasps whose larvae consume the insect (they target younger scales) or the eggs under the scale.\u00a0There are scale insects that are serious plant pests, scale insects that are used to control invasive plants, and scale insects that are \u201ccultivated\u201d because they\u2019re used to produce shellacs, waxes, and red dyes.\u00a0<\/p>\n\n\n\n The two, big divisions of scale insects are \u201ccushiony\u201d and \u201carmored\u201d scales.\u00a0Cushiony scales tend to be lumpier than armored scales, and they\u2019re permanently attached to their waxy covering. The excess sap that they consume, released as a sweet fluid called \u201choneydew,\u201d attracts other insects to feed on it, and some species of scale are cared for by ants that protect the scales from predators, harvest the honeydew, and help the crawlers find fresh twigs.\u00a0The downside of honeydew is that sooty mold grows on leaves where its sticky sweetness falls, which interferes with photosynthesis and isn\u2019t very wholesome looking.\u00a0A species of cottony scale was featured in a BOTW years ago<\/a>.<\/p>\n\n\n\n Dogwood scurfy scales are armored scales, and armored scales are in the family Diaspididae, the largest scale family (2650 species). Armored scales feed on hosts from 180 plant families.\u00a0They\u2019re not attached to their waxy cover, are smaller and flatter than cottony scales, and they don\u2019t produce honeydew. Their tough \u2013 armored- coverings may be round, elliptical, or oyster shell-shaped and may have concentric rings\/ridges.\u00a0The female incorporates the shed skins from her crawler stage into her growing shell, and the wax is made and shaped by a structure called the pygidium at the rear of the abdomen.\u00a0The critter below the scale has knob-like antennae, no legs, and little distinction between head and thorax. \u00a0<\/p>\n\n\n\n Not surprisingly, with so many species of armored scales, there are many different lifestyles. In general, she lays her eggs or live young under her scale, which has a slit at the rear that allows them to exit.\u00a0Her eggs overwinter under the shelter of her scale, though she\u2019s no longer alive when they hatch.<\/p>\n\n\n\n The BugLady saw a paper that said that some armored scales may get around by phoresy \u2013 hitchhiking \u2013 sticking to their six-legged taxi cabs (the study identified a fly, a ladybug, and an ant) with the help of a few \u201csuction-cup\u201d-tipped hairs on each of their legs<\/p>\n\n\n\n Fun Fact About Ant Partnerships<\/p>\n\n\n\n An odd relationship has evolved between a species of African ant and a species of armored scale (which, remember, have no honeydew to trade for ant favors).\u00a0The ants shelter the scales in the galleries\/tunnels they live in under tree bark \u2013 the ants are so specialized that they spend their whole lives there. The scales no longer need protection from the elements or from predators, so most of them are \u201cnaked,\u201d though some still make wax and other scale-building materials that the ants eat along with the crawlers\u2019 shed skins and various scale \u201cexcretions<\/em>.\u201d\u00a0The whole thing hinges on the ant queen finding a suitable host tree\u00a0and<\/em>\u00a0rounding up crawler-aged scales during her brief nuptial flight.<\/p>\n\n\n\n As the poet Muriel Rukeyser once said, \u201cThe world is made of stories, not atoms<\/em>.\u201d<\/p>\n\n\n\n Scurfy Dogwood Scale\/Red-Osier Scale Insect<\/p>\n\n\n\n The BugLady started nibbling around the edges of this episode at least three years ago and hit a brick wall pretty fast.\u00a0The Extension and Horticultural sites mostly said \u2013 \u201cYup, dogwoods get scales<\/em>\u201d but offered no names or biographies, so, the original iteration of this BOTW was something like, \u201cThese are dogwood scurfy scales \u2013 they\u2019re everywhere, but no one\u2019s written anything about them \u2013 thanks as always to PJ at the Insect Diagnostic Lab in Madison for pointing the BugLady toward an ID<\/em>.\u201d\u00a0<\/p>\n\n\n\n But the BugLady could never do that, so\u2026..<\/p>\n\n\n\n In her initial search for a name, the BugLady came across the pine leaf scale (Chionaspis pinifoliae\u00a0<\/em>https:\/\/bugguide.net\/node\/view\/361628\/bgimage<\/a>) that looked similar, but she thought it was unlikely to be her scale because, well, pine needles.\u00a0The dogwood scale suggested by PJ is\u00a0Chionaspis corni;\u00a0<\/em>in the same genus, but when you Google\u00a0Chionaspis corni,\u00a0<\/em>most hits are for\u00a0Chionaspis pinifoliae.<\/em>\u00a0Bugguide.net lists no other genus members and although the dogwood scurfy scale is common here, does not even show the genus as occurring in Wisconsin (buggide\u2019s caveat about its range maps is \u201cThe information below is based on images submitted and identified by contributors. Range and date information may be incomplete, overinclusive, or just plain wrong<\/em>\u201d).<\/p>\n\n\n\n![\"bugs](\"https:\/\/uwm.edu\/field-station\/wp-content\/uploads\/sites\/380\/2024\/11\/scale-dogwood22-1rz.webp\")
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