Howdy, BugFans,

These lovely, fragile-looking insects have fluttered around the edges of several BOTWs over the past 17-plus years, and it’s time for them to have an episode of their own. 

A bit about their pedigree: they are in the oddball order Neuroptera (“nerve-wing”), an order that’s undergone a fair amount of tinkering. Presently, it’s home to the doodlebugs/antlions, the owlflies, and a whole bunch of different varieties of lacewings; and it’s the former home of the snake, alder, fish, and Dobsonflies (hellgrammites). Neuropterans are soft-bodied insects with four, similarly-sized, conspicuously-veined wings, and chewing mouthparts, and they practice complete metamorphosis (going through egg, larva, pupa, and adult stages). Their larvae are predators.

A note about Green lacewing taxonomy – members of the genus Chrysoperla are frequently encountered across North America, as are members of the genus Chrysopa. They look a lot alike, their photographs can be confusing, and various species have been swapped back and forth between the two genera for a long time (and at one point, many species were lumped as a single species). When the BugLady looks at the Green lacewing shots she’s taken over the years, a number of different species seem to be represented – pale dorsal stripes on some, small thoracic spots on others, no definitive markings at all on still others – so she will keep this general. 

Green lacewings are in the suborder Hemerobiiformia, which includes the Dusty, Pleasing, Beaded, Brown, Giant and Moth, Mantid, Spoon-Winged, and Spongilla lacewing families as well as the Green lacewing family Chrysopidae (from the ancient Greek words for “gold” and “face”). They are also called Golden-eyed lacewings and “stinkflies” (because members of several genera release bad-smells when handled), and their larvae are known as aphid lions or aphid wolves. 

The “alligator-like” larvae live up to their nicknames, grabbing insects – including eggs, pupae, and caterpillars  but especially aphids – with their sickle-shaped jaws, injecting them with a paralyzing venom, and  (which, in the case of an aphid, takes about 90 seconds). They often hold their prey aloft as they’re draining it. Some sources report that the larvae wave their abdomens back and forth as they roam the leaf tops, and others say that they swing their heads back and forth, seizing prey when they bump into it (their sense of touch is well-developed). 

It’s also said that some species can account for 100 to 200 aphids a week, and if they can’t find their normal quota of prey, they have no qualms about eating other lacewing larvae. Depending on the species, adults may be predators, or they may be vegetarians that feed on nectar, pollen, and honeydew (the sugar water exuded by some bugs). 

Lots of insects and spiders eat lacewings. Adults are nocturnal and are poor flyers, but they can hear the echolocation calls of bats and avoid them by folding their wings (presenting a smaller target) and dropping to the ground. Some parasitic wasps search out lacewing cocoons and lay their eggs on them, and their larvae eat the cocoon’s contents.

Green lacewings court by “singing.” Males vibrate their abdomen and send a signal out through the substrate, and females hear/feel his song through their legs and respond with their own, identical song, the pair singing part duet/part call-and-response. Even though we may not be able to tell species apart visually, their songs differentiate them. 

Females make stalks by touching the underside of a leaf or twig with their abdomen and then pulling back, extracting a thread (manufactured in her reproductive system) that hardens immediately, and they  (and some create a cool, ). Eggs are laid where there are aphids nearby. It’s theorized that suspending the eggs protects them from predators, including their newly-hatched, immediately-hungry siblings. About three weeks after hatching, , and adults emerge about five days later. There are several broods per year, and they overwinter as adults or as pupae. 

Some species of Green lacewings have hairy/spiny, “trash-carrying” larvae – larvae that stick debris – and sometimes bits of dead prey – to their backs, creating a shield that they present to aggressors.  Does the disguise help them avoid aphid-farming ants? Hide them from predators? .   

Because of their dining habits, lacewing larvae are sold as a biological control of aphids, the Catch 22 being that when they’ve finished eating the aphids or mature as adults, they may move on. 

A Note from the Pulpit: Because of their nocturnal habits, adult lacewings are often attracted to and killed by bug zappers. The vast (vast) majority of insects killed by bug zappers (about 95% in one study and more than 99% in another) are NOT target species like mosquitoes and other biting flies (which are not attracted to the zapper’s UV light). The vast (vast) majority are pollinators like moths, or predators like lacewings, or just innocent passers-by. At a time when insect numbers are going down globally, and we recognize all the “ecosystem services” they provide (including feeding the birds), the idea of this degree of collateral damage is repugnant.

Fun Lacewing Facts (from the North Carolina State College of Agriculture and Life Sciences).

• For many years, biologists thought their eggs were the fruiting bodies of a fungus they called Ascophora ovalis. The true nature of these eggs was first discovered in 1737 by Rene Reaumur, a French physicist, biologist and inventor.

• As larvae, lacewings and antlions do not have a complete digestive system: the midgut ends in a dead end. Waste materials accumulate in the midgut throughout larval development and are finally expelled only after a connection is made with the anus near the end of the pupal stage. The accumulated fecal material is called a meconium. 

CICADA ADDENDA

Last week’s cicada story is the gift that keeps on giving.

ERRATUM – the quote about cicadas mistaking people for trees, mistakenly attributed to the EPA, was actually from Cicada Mania. The BugLady thought it sounded a bit un-EPA-ish, but she had just been on their site, and her brain hiccoughed.

AND – Thanks, BugFan Bob.

AND SUPER POWERS (Oh My!) – the wings of cicadas and a number of other groups like honey bees, butterflies, dragonflies and damselflies have what one scientists calls “anti-biofouling and antimicrobial” properties! Not chemically antimicrobial but structurally antimicrobial. How does that work? The surface of the wings is covered with “nanopillars” – columnar structures with a diameter of about 100 nanometers (one-one thousandth the diameter of a human hair), with “spikey” tips. Bacteria that land on them literally get impaled, tearing their cell walls, which kills them. The nanopillars are (somehow) self-cleaning, getting rid of the debris that might serve as a medium for more bacteria to grow. . Stay tuned.

The BugLady

The post Green Lacewings appeared first on Field Station.

One of the last bugs to grace the BugLady’s porch light in autumn is the brown lacewing (she sees its jewel-like cousin, the green lacewing, in mid-to-late summer). Because of this year’s long, mild fall, brown lacewings straggled on into early November.

Brown Lacewings

Brown lacewings belong to the order Neuroptera (“nerve-winged”). The order seems to be under constant review by taxonomists, and its inhabitants have been shuffled and re-dealt into suborders under the superorder Neuropterida, which embraces lacewings as well as oddballs like (yes, these occur in Wisconsin), (so do these), (and these), and . Snakeflies and the more familiar alderflies, fishflies, and dobsonflies (hellgrammites) have been dealt out and given their own orders but are sometimes included in discussions about the Neuropterida. Neuropterans are generally soft-bodied, weak-flying insects (they’ve been likened to drab, awkward damselflies) that are active in the dusk/dark and that have complete metamorphosis (egg-larva-pupa-adult). Brown lacewings are in the family Hemerobiidae, with about 500 species worldwide, 60 in the U.S.

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Adult brown lacewings have four-wings and are a half-inch-long(ish), with light brown wings, often patterned, and they are less conspicuous—and hairier—than green lacewings (family Chrysopidae). They have chewing mouthparts and conspicuous eyes, and they somewhat resemble caddisflies. Despite what some books say, the stiletto-shaped larvae of brown lacewings do not (cannot, because they lack dorsal setae and tubercles to stick things to), disguise themselves by fastening the dry shells of their prey to their backs (green lacewing larvae do and are sometimes called “trash bugs” for their troubles). Larvae use their long abdomen as an aid in climbing, and they have .

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Brown lacewing adults and larvae richly deserve their nicknames of “aphid lions” and “aphid wolves,” but they also prey on small critters like mealybugs, white flies, spider mites, scales, and on insect eggs (including those of their confreres). Despite their good camouflage, brown lacewings are eaten by birds, ladybugs (fellow aphid-eaters), dragonflies, and spiders.

Because their list of food items includes some agricultural pests, and because the adults are relatively long-lived (several months) and the females relatively fecund, they have been deployed to act as biological controls (you can buy them). In a 1923 “biography” of a brown lacewing named Micromus posticus (much of the brown lacewing literature is pretty dusty), Ohio Agricultural Station researcher Clifford R. Cutright noted that a brown lacewing may eat 41 aphids during its larval stage and an adult female may lay more than 450 eggs.

According to “The Life Histories and Stages of Some Hemerobiids and Allied Species (Neuroptera)” by Roger Smith, in the Annals of the Entomological Society of America, 1923,

A very noticeable feature of females ready to oviposit is the large and much-distended abdomen (the BugLady wonders if the plain-winged brown lacewing pictured here might be a female). The abdomen may assume a salmon or a light amber coloration between the sclerites because of the eggs within. They walk about excitedly, stop suddenly, and bend the abdomen forward, arching it in the middle. They walk about excitedly, stop suddenly, and bend the adomen forward, arching it in the middle. The egg… is deposited flat on the substratum to which it adheres. The time required for this performance is but a few seconds.

Green lacewing eggs are set like tiny knobs on the end of stiff stalks, but brown lacewing eggs are laid directly on leaf surfaces, buds, bark, etc. near aphid populations. The larvae are active and fleet of foot in the first instar but may become more sedentary in the second two instars. One reference said that larvae whip their heads from side to side, a behavior that the BugLady saw in a larva that ran through a herd of aphids, brandishing one of their fallen comrades. They often hunt on milkweed leaves, but they prefer aphids that feed on plant juices from milkweed species whose cardenolide (toxin) levels are low. Mature larvae spin loose, double-walled cocoons in sheltered areas; there may be several generations per year, and the (or as an adult in Southern climes).

The BugLady thinks that a few of her lacewings with streaky wings might be Micromus posticus, a species that’s found across North America but seems more common in the Great Lakes area. This species was featured in an article suggesting that an increasing number of sightings of the species in Quebec could be part of a northern migration made possible by global climate change. The authors pointed out that the status of fall-occurring species can be hard to determine because systematic insect collecting drops off after September.

Interesting brown lacewing factoids:

• Adults feign death when alarmed, tucking their “chins” down and their antennae between their stiffened legs.
• Their intestines are plugged and they don’t poop until they are adults (not uncommon in this group). A silk-spinning gland occupies the larval posterior.
• Larvae “glue” themselves to the substrate by the tip of the abdomen while molting so they won’t fall during ecdysis.
• Using their middle and rear pairs of legs, brown lacewings can jump into the air like a grasshopper on their way to becoming airborne. They leap first, and then they flap. Because they use four legs, they can launch from surfaces that might “give” beneath them, because their weight is spread out.

 
The BugLady

The post Brown Lacewing (Family Hemerobiidae) appeared first on Field Station.

These prehistoric-looking insects are members of the order Neuroptera (nerve-wing), named for the network of veins in their wings. The order embraces oddballs like mantisflies, snakeflies, antlions, and owlflies, but it also includes the more familiar alderflies, fishflies, and dobsonflies. These last three are, increasingly, split off into their own order—Megaloptera (mega-wings), but we’ll consider them together. Nerve-winged insects tend to be soft-bodied, nocturnal, awkward fliers. They have complete metamorphosis—egg to larva to pupa to adult—involving a complete change of appearance.

Green Lacewings

Green lacewings are small beauties found clinging to grass stalks or sitting near porch lights. Sometimes called “stinkflies,” they can release a bad smelling chemical when they are handled. For all their fragile appearance, both the immatures and adults are effective and ravenous predators. Referring to larval lacewings in his Field Guide to Insects of North America, Kaufman says that “with their tong-like jaws, aphid lions skewer their victims, and then suck them dry.” He goes on to describe the habit of some species whose larvae are hairy/spiny to “pile the dry carcasses atop their bristly backs or decorate themselves with other debris.” These “trophies” disguise the aphid lions and allow them to sneak in under the radar of the ants that farm aphids (more about that in a later episode). They are considered to be important controllers of pest insects. Lacewing eggs are laid on vegetation on the ends of hair-like stalks, and the larva eventually pupates in a spherical cocoon. The BugLady recognizes, in the picture of the lacewing larva in Kaufman’s book, the wee beastie that, during her entire life, has been dropping out of trees and biting her.

Fishflies

Fishflies, weighing in at 1 ½ inches in length with a 2-plus inch wingspan, are smaller than their more dramatic cousins, the 5 inch long dobsonflies, (the adult male dobson’s huge jaws are just for show, but the smaller-jawed female will bite, memorably, when handled). When startled into (weak) flight during the day, they might be mistaken for a mid-sized dragonfly.

Eggs are laid and are glued together (nocturnally) in damp spots—logs, rocks, twigs, the undersides of leaves—above/near quiet water, and when the young hatch (nocturnally) they drop/crawl into the water. The larvae of both dobsonflies and fishflies are called hellgrammites. Hellgrammites have a plan A, B, and C for breathing. A: When on land, they can breathe through spiracles like terrestrial insects (but they’re too smart to try that underwater); B: Underwater, they absorb, through their soft skin, oxygen that is present in the water; C: The filament-like fingers that protrude from their sides are gills. Some deluxe models include additional plans—gill-tufts at the base of the filaments, and/or breathing tubes that reach to the surface.

When, after one to three years, the hellgrammites are ready to pupate, they do it in synchrony with others in their age class. Within a few days, the whole cohort abandons the water (in a sometimes-dramatic migration) to pupate on land. They pupate underground in spaces that they excavate. In his excellent A Guide to Common Freshwater Invertebrates of North America, J. Reese Voshell, Jr. notes that vibrations caused by thunder storms may stimulate the exodus of mature hellgrammites that are ready to pupate!

Although the immatures are aquatic predators with impressive mandibles, the adults either do not feed or are vegans that feed minimally on liquids.

 
The BugLady

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