Shawnee News-Star Wed July 6th 2016 Article Becky Emerson Carlberg Stop with the dramatics and think in terms of tree identification.   It's easy to locate a persimmon or pecan tree these days.   Most have gauzy webs that wrap around the branches like cotton candy, loose boxing gloves or even baby blankets. Don't get your boxers [...]

Shawnee News-Star Wed July 6th 2016 Article

Fall Webworm or Tent Caterpillar

Becky Emerson Carlberg

Stop with the dramatics and think in terms of tree identification.   It's easy to locate a persimmon or pecan tree these days.   Most have gauzy webs that wrap around the branches like cotton candy, loose boxing gloves or even baby blankets. Don't get your boxers in a knot.   The caterpillars inside indeed eat the leaves and often the tree winds up looking 'moth-eaten' (well yes, moths are the end result), but the tree usually bounces back.   You are seeing an important circle of life that happens every spring and fall.   With so much emphasis on butterflies, moths, bees and other pollinators, the caterpillar stage often goes unnoticed.   You can't say this about the caterpillars that spin massive webs.   Here they are!

The usual response when seeing web worms is go dig out the chemicals or, my dad's favorite, the torch.   My father and his brothers were pyromaniacs when it came to pests.   Honeysuckle vines, wild berry thickets or tents of webs, with enough gasoline the irritating natural lifeforms became toast.   Wait one minute.   The web caterpillars are part of an elaborate food chain and have been around for thousands of years. The spring tent caterpillars belong to the Malacosoma genus.   Malaco is Greek for soft and soma is South Asian for body. Soft-bodied and gregarious these caterpillars are.   The summer-fall webworms are in the genus Hyphantria which means weaver of threads.   These communal caterpillars build very strong webs.

Both types of caterpillars begin life crowded together within masses of hundreds of eggs.   The timing of the egg hatch coincides with bud break for the tentworms (thus they appear early in the spring) and webworms depend on the availability of mature leaves.   Both groups of siblings stay together, but their modus operandi is different.   Tentworms spin their multi-layered webs in a fork of the tree that receives the morning sun.   Webworms begin life at the outer ends of branches and wrap the leaf where they are born in silky webbing.   From here they extend the web network leaf by leaf as they eat and grow, sometimes enveloping a small tree.

Tent caterpillars go out on foraging trips for young leaves (plants in the rose family are especially adored) during the day and retreat into their shelters at night.   They leave a pheromone trail similar to those of ants.   The tentworms may stay indoors if weather becomes a problem or simply to rest. Since these larvae can't digest older leaves, time is of the essence.

The webworms munch leaves during the day inside their web shelters, and join with other relatives to build huge nests.   When the caterpillars are half grown (the orange headed race is dining around my house), they reverse activities and rest during the day inside their nests, but move out at night to eat.   Many species of deciduous trees are fair game, but since fall is imminent, their leaves are going to soon fall away and the impact is minimal.

Tent caterpillars pupate into small thick-bodied brown nocturnal moths with wings swung back at angles like fighter jets.   Fall webworms become ermine white nocturnal moths with similarly constructed wings. Tentworms produce one generation while fall webworms shoot for two or possibly more.

The black and yellow-billed cuckoos love hairy caterpillars, and relish both the tentworms and fall webworms.   Red-shouldered hawks prefer to line their nests with tent caterpillars. The brilliant orioles, bluejays, chickadees, scissor-tailed flycatchers, and nuthatches also find the packages of protein delectable as do bats, frogs, mice, skunks, squirrels, predatory assassin bugs, parasitic wasps and bears. One researcher reported, after spending days tethering out bear scat (poop), that a single bear apparently could eat 25,000 tent caterpillars in one day.   What a job.

Despite your feelings, webworms are at best a temporary nuisance.   Go close to one nest of webs and peer inside.   The caterpillars seem to levitate and form interesting designs.   Some may gather together and appear as flowing water (in slow motion.) Think of the patterns of fast moving birds in the sky or fish in the sea or even humans in cars or on foot.   Carefully examine these cooperative small occupants of nature and think:   We're all related and linked together on this Earth. Be kind.