Monday, November 13, 2017

Winter Signs of Insects

     Only the warm-blooded birds and mammals are active and noticed in the Middle Atlantic States in winter.  Cold-blooded creatures, including insects, are not seen much during that harshest of seasons.  But in winter we see several signs of the insect activities that happened during the warmer months when they were active.  Those signs of insects make being outdoors in winter more interesting.  Those signs indicate the presence of insects, and a bit of their life histories that we can read in winter.
     The nests of two kinds of wasps and a related hornet are seen in winter with little effort.  Northern paper wasps live in sunny, open habitats.  Adults of this species sip nectar, and juice from rotting fruit, while their larvae in their six-sided, paper cells consume insects caught, pre-chewed and brought to the larvae by adult wasps.
     In spring, about a dozen reddish-brown and yellow-ringed female paper wasps work together to make an uncovered paper nest of several cells that they attach up-side-down to an overhanging boulder, roof or other sheltering place.  Cell openings point down to shed rain.  Each paper nest of these wasps is constructed of chewed wood and the wasps' saliva.         
     Worker female black and yellow mud dauber wasps gather small bits of mud and shape them into a few vertical, side-by-side, tubular cells, each over two inches long, under roofs, cliffs and other protective niches.  Each tube has a few compartments.  A paralyzed spider is deposited in each cell, a wasp egg is laid on each spider and the cell is closed off with mud.  Each larva eats its spider, pupates in its cell and emerges as an adult.  Adult wasps ingest flower nectar.
     Worker female bald-faced hornets chew wood and mix it with their saliva to make football-sized, paper nests in deciduous trees on lawns and in woods and meadows.  Each hornet nest is composed of many six-sided cells inside, completely covered by a few layers of gray paper with an entrance in the bottom of that nursery.  All adult hornets sip flower nectar, but larvae eat pre-chewed insects, delivered to them in their cells by the adults.  In fall, males and female workers die and the queen of each colony burrows into the soil to await spring.  Therefore, each decorative nest is empty in mid-winter and can be safely collected with no harm to hornets or people.  The hornets will never use that nursery again.
     Small groups of female eastern carpenter bees are so-named because each one of them chews round holes the size of their bodies and a few inches deep in the undersides of dead wood in trees and human-made structures, including fence railings and covered bridges.  Each female places a ball of pollen and nectar in the back of the tube she chewed out and lays an egg on that ball.  Then she seals off that chamber with wood chips and places another ball of pollen and nectar in the next chamber to the front, lays an egg on it and seals it.  She continues that until her burrow is full and sealed off.  Each larva consumes its food, pupates in its chamber and emerges as an adult.
     The predatory praying mantises survive winter in the egg stage in round, beige-colored, styrofoam-like masses, each about one inch across and attached to a weed or twig in an overgrown field.  Each female exudes froth as she lays eggs at some time in October.  That froth hardens and protects the embryos inside until they hatch the next May.
     One can see the tunnels of carpenter ants in standing dead trees in winter.  Piles of sawdust grow under the entrances to their homes as the ants throw that waste wood out of their burrows.  Those excavations protect the ant colonies where they live and rear young.  But pileated woodpeckers chip vertically rectangular holes in dead wood of trees to extract and consume carpenter ants.
     Various kinds of bark beetles are small, and live and pupate between the dead wood and bark of standing trees.  They chew elaborate tunnels under the protective bark, which, to us, are beautifully intricate patterns when the bark falls away.  Woodpeckers chip many bark beetles out of the wood and consume them.
     Rounded galls on goldenrod stems were made by the larvae of spot-winged flies.  Female flies lay eggs on new stems in late May.  Each larva burrows into a stem and eats out a chamber.  The irritated plant forms a gall around that chamber.  The larva overwinters in that form, and in spring chews a tunnel to the surface wall of its home, pupates in its chamber and pushes through the final thin wall as an adult fly.  We see the swollen part of the stem and the hole in it.
     Elliptical goldenrod galls are formed by the larvae of a kind of small moth.  In autumn, each adult, female moth lays eggs singly on the lower leaves and stems of goldenrods where those eggs overwinter.  In the warmth of spring, the larvae hatch, crawl to new goldenrod shoots and dig into end buds to the stems where they feed on that vegetable material.  The stem forms an elongated gall around each larva.  In late July, each larva bores an exit hole in the upper end of its chamber and plugs it with its silk, and plant material.  Then each larva pupates and emerges late in August as an adult moth.  Elliptical galls are empty in winter.     
     In the middle of April, colonies of sibling tent caterpillars build webs in crotches of limbs on various kinds of cherry trees to protect themselves from birds and other insects that would consume them.  Each day they leave their webbed nests to eat leaves.  Their homes grow as they do and are soon littered with feces and shed skins.  By late May they leave that webbing to pupate in the ground, later emerging as small moths ready to breed.  The tattered webs remain in the trees until winter.
     In August, colonies of sibling fall webworms build large webbed nests, mostly in black walnut trees.  Webworms construct webs at the ends of leafy branches and enclose the foliage in those protective homes.  They ingest leaves inside the web where they are better protected from birds and other critters that would eat them.  The larvae leave the webs late in fall and pupate in the soil, leaving empty homes behind as reminders to us of their late-summer activities.
     The one-inch-long bagworms are the larvae of a kind of small moth.  These caterpillars carry their protective cocoons with them as they eat vegetation.  Each larva covers its home with bits of the vegetable material, including that of northern white cedars and red junipers, it ingests, which camouflages that creature.  Eventually it fastens its home to a twig and pupates inside it. 
     Emerging adult males have one-inch wingspans.  Females don't develop wings or legs and never leave their cocoons.  No adult eats anything.  Males find females in the latters' homes and mate with them.  Each female lays eggs in her cocoon and dies.  The eggs overwinter in their mother's cocoon that reminds us of the moths' summer activities as caterpillars.
     The summer activities of insects are fascinating, and we can see remnants of those life histories in winter.  All we have to do is get out and look for them in any and every habitat.                        

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