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Caterpillar(?) in Leaf Cocoon identification - Missouri


A small chunk of leaves fell off of a potted tomato plant. We noticed our cats taking an interest in it once it started moving. Then a little caterpillar poked its head out. What kind of bug is this and should we worry about our plant?


This is the larvae (caterpillar) of a bagworm moth (family Psychidae).

Source: Wikimedia Commons; Credit: Bernard DUPONT

From Wikipedia:

The caterpillar larvae of the Psychidae construct cases out of silk and environmental materials such as sand, soil, lichen, or plant materials.

There are about 240 genera, so I will leave IDing to lower taxonomic levels up to you. However, based on the striations of the caterpillar and your lcoation, the Evergreen Bagworm Moth doesn't seem like a bad guess…


On Sunday as I was working in the garden, I noticed a few cocoons on the forsythia bushes by the driveway. One was familiar, but one was not. My husband asked, “Is it a bad bug? Or a good bug?”

A quick internet search later revealed it to be the cocoon of a familiar garden moth, a harmless creature who probably pollinated a few flowers each year and added color and liveliness to the garden. It would have been a shame to harm the cocoon but many gardeners, unaware that some good bugs spin cocoons too, might have destroyed


Caterpillar Species Included in this Guide

Tomato Hornworm

White-Lined Sphinx

Emperor Moths

Tiger Swallowtail

Polyphemus Moth

Cecropia Moth

Imperial Moth

European Puss Moth

Rustic Sphinx

Hickory Horned Devil

The Drinker

Eumorpha Sphinx Species

Oleander Hawk Moth

Elephant Hawk Moth


Ecosystem Connections

Moth caterpillars, which are soft and nutritious for potential predators, don’t move very fast and cannot fly, so generally speaking, they are prime dinner fare for many species of birds and other predators. Therefore, caterpillars of many species have developed ways to avoid being eaten. Camouflage is one typical defense strategy. But in this group, the bright color patterns of many species warn potential predators of stinging spines or hairs. This saves the caterpillar from expending time and energy building a leaf tent or other shelter, or from having to feed only at night.


Life Cycle

Moths, like beetles, bees, and flies, undergo complete metamorphosis: after a series of wormlike juvenile (larval) stages, they enter an inactive phase called a pupa, then emerge as sexually mature, winged adults. (Other insects, such as grasshoppers and true bugs, have juvenile stages that look more or less like the adult form, only smaller and minus the wings — their life cycle is called incomplete metamorphosis.)

Some species have only one brood a year, while others have two or more.

Moths begin life as eggs that are typically laid on or near the host plant or other larval food source. The larvae (caterpillars) hatch from the eggs and begin eating and growing. As they grow, caterpillars repeatedly molt into larger exoskeletons (“skins”). Each stage is called an instar. The caterpillars within a single species may look different upon each molt.

When the caterpillar has eaten and grown sufficiently, it typically burrows into the soil surface leaf litter and enters the pupal stage. The pupa is usually protected by a silken cocoon, often with bits of leaves or other materials incorporated into it.

Different moth species overwinter at different points in the life cycle: some overwinter as eggs, some at different points in the caterpillar development, and some as the pupa. A few overwinter in sheltered places as mature, winged adults. Most species only live a few days or a few weeks as winged adults.


Stag Beetle

While most people associate cocoons with moths, there are other insects that use cocoons during the pupa stage. Many beetles, including the stag beetle, spin a cocoon underground. The stag beetle lives underground during the larval stage, where it feeds on rotting wood. It may remain in the larval stage for up to six years. The larva then spins an underground cocoon in the autumn and becomes an adult beetle in the spring. It only lives a few weeks as an adult because the adult stag beetle does not eat. It only mates and then dies.


Corn earworm

Corn earworm (Figure 79), Helicoverpa (=Heliothis) zea (Boddie), Noctuidae, LEPIDOPTERA

DESCRIPTION

Adult corn earworm moths vary in color and markings, but the forewings are usually light yellow or yellowish brown, with dark irregular lines and a dark area near the tip. The hind wings, usually partially covered by the forewings, are white with irregular dark markings near the border. Wingspan is about 40 mm. The eyes of the moths are green.

When first laid, the hemispherical and ridged eggs are pale white. A pale reddish band develops around the egg, and then it darkens prior to hatching.

Larvae vary from pale green to dark brown, with alternating light and dark longitudinal stripes, generally brown or orange, running the length of the body. The head is dark yellow or reddish orange (Figure F). Newly hatched larvae are about 1.6 mm long and yellowish white with dark head capsules. Full-grown larvae are about 43 mm long.

Pupae are glossy brown and taper at one end. The pupa is about 32 mm long and 6 mm wide.

Distribution

The corn earworm feeds on many plants throughout the world. In the United States, the corn earworm is a destructive pest of corn, cotton, and tomato, especially in the South. The corn earworm also is referred to as the cotton bollworm or the tomato fruitworm. Two similar and related species, the tobacco budworm, Heliothis virescens (F.), and Heliothis phloxiphaga Grt. & Rob., may be confused with the corn earworm. Damage to the plant by each species is similar.

Host Plants

The corn earworm feeds on a wide variety of plant species. Ageratum, carnations, chrysanthemums, and roses are severely injured by the corn earworm in unscreened greenhouses. Additional hosts include amaranth, canna, cleome, dahlia, geranium, gladiolus, hibiscus, lathyrus, lupine, mint, morning glory, nasturtium, phlox, poppy, and sunflower. The tobacco budworm and H. phloxiphaga also feed on aster, columbine, delphinium, and snapdragon.

Corn earworm larvae feed on all exposed plant parts, particularly the buds and flowers, and may defoliate the plant. Infestations on flowering plants are more likely in the fall after many of the field crops and weeds are unattractive, unsuitable, or unavailable for moths. Moths, attracted to these flowering hosts, may feed on nectar and oviposit on the plant. Moths do not damage the plant.

Life History

Adult moths begin to emerge from overwintering sites in early May and are most active at night. Male and female corn earworms live about 10 to 14 days. During that period, each corn earworm female may lay 450 to 2,000 eggs singly on host plants. Eggs are laid on open foliage, but are usually densest on younger leaves. Eggs hatch in 2 to 5 days. The larval stage lasts about 2 to 3 weeks and has five or six instars. Smaller larvae tend to occur in new, still-rolled foliage, whereas larger larvae tend to feed on open leaves. All stages tend to feed on flowers, tender new leaves and fruit. Late-stage larvae tunnel 5 to 15 cm into the soil and pupate. The pupal stage lasts about 2 to 3 weeks. Adults then emerge from the soil. Duration from egg to adult emergence is 6 to 8 weeks under field conditions. Corn earworm overwinters as a diapausing pupa in the soil and undergoes several generations each year. In the North, the pupa can survive only during mild winters. Adults are strong fliers and, in the spring, are spread northward from warmer overwintering areas. Infestations in greenhouses occur when the corn earworm moths fly through open doors, windows, and vents and then deposit eggs on the plants. Corn earworm larvae are cannibalistic.

Damage by corn earworms in a greenhouse can be reduced by adequate screening of window and open areas, as well as proper sealing of door edges. Use of natural enemies (e.g., Trichogramma wasps and predatory insects) may help to reduce infestation by corn earworm. Chemical insecticides provide adequate control of corn earworm. For chemical control recommendations, consult the current Cooperative Extension publications on ornamental plant pest management.

Figure 79. Corn earworm. A, B. Adult. C. Eggs. D. Larva. E. Pupa.

Figure 79. Corn earworm. A, B. Adult. C. Eggs. D. Larva. E. Pupa.
Figure F. Corn earworm.

Injury caused by caterpillars

Healthy, well-established ornamental plants can usually tolerate caterpillar feeding.

  • Most caterpillar feeding only affects the plant's appearance.
    • There are a few exceptions, such as spruce budworm defoliation on spruce and balsam fir.

    Caterpillars can cause different patterns of damage to leaves. Sometimes different stages of the same caterpillar can create different types of damage.

    • General feeding: eating entire sections, even entire leaves.
    • Skeletonizing: feeding between the main veins of leaves.
    • Windowpane feeding: feeding on one layer of leaf tissue between the veins. The damage is translucent (semitransparent) before eventually turning brown.


    ‘Log House’ Like Cocoon of The Bagworm Moth

    The bagworm moth (Psychidae) of the family Lepidoptera might be a pest for Botanists, but for Lepidopterists they are one of the rare architects of the animal world. As soon as the caterpillar of the bagworm moth hatches, it weaves a silk cocoon around itself, inside which it will live until it grows into an adult moth. To make its life as a larva safe and protected from predators, the caterpillar reinforces its silk cocoon with pieces of twigs, leaves and other plant matter. Depending on what debris is on hand when they are forming the cocoon, the resulting shelter might look like a bunch of twigs, or in exceptional cases, a tiny log house. These strcutures are called cases, and bagworm moths are also known as "case moths”.

    The cocoon of the bagworm moth looks like a tiny log house. Photo credit: melvyn yeo/Flickr

    The cases of bagworm moths are attached to rocks, trees or leaves, but they do not stay rooted to the same spot. The caterpillar remains mobile as it hunts for food, and it carries the protective case along with it wherever it goes. They move somewhat like turtles, pushing their heads out of the opening at the top to advance forward and then drag the case behind. The case has another, smaller opening at the bottom. The caterpillar comes out from the top to feed and ejects the waste from the bottom end. The bottom opening is also the exit hatch for the emerging adult. If the caterpillar feels threatened it can seal off the end of the cocoon, cutting a new opening once the threat has passed.

    As the bagworm grows, it expands its case by adding more twigs to the top. They poke their head out of the top of their case, collect additional twig, cuts them off to appropriate size and attaches them temporarily to the top of the case. They then disappear inside to cut a slit where they plan to attach the new stick.

    The cases of the bagworm moth are incredibly tough and very difficult to break open. And since the cases are composed of materials from their habitat, they are naturally camouflaged from predators such as birds and other insects. The attachment substance used to affix the case to host plant, or structure, is also very strong, and in some case require a great deal of force to remove given the relative size and weight of the actual structure itself.

    Bagworm cases range in size from less than 1 cm to 15 cm among some tropical species. Each species makes a distinctive looking case. The cases of the more primitive species are flat, while specialized species exhibit a greater variety of case size, shape, and composition.

    Bagworm moths spend most of their lives in the caterpillar phase, and hence inside the case. The females continue to live in their cases after they’ve pupated into adult moths, but the males leave their cases after pupation to fly off in search of females to mate with. After they mate, the females lay their fertilized eggs in their old bags. Once the larvae hatch, they will create their own tiny log house.


    Butterflies and Skippers

    In North America, the Lepidoptera — the insect order comprising all the moths and butterflies — contains more than 30 superfamilies. All of them are various types of moths, except for one: superfamily Papilionoidea, which comprises the butterflies and skippers. Like moths, they have tiny, overlapping scales on their wings. These seem like dust when they rub off onto your fingers. The scales can be brightly colored, or they can be drab.

    About 700 species of butterflies (including the skippers) occur in North America north of Mexico. Most of us have a general idea of what a butterfly looks like, but to be certain, note the following characteristics:

    • Antennae, in butterflies, are filaments tipped with a club. In the skipper family of butterflies, the antennae tips are also hooked. (Meanwhile, moths’ antennae are filaments with no club tip, or else they are shaped like feathers.)
    • The typical wing position, when perched, is either straight out to the sides (“wings open”), or the wings are held together, straight up over the body. (There are exceptions, but moths typically fold their wings over their body like a tent, or hold them flat but swept back at an angle to the body, looking triangular from above.)
    • During metamorphosis, the chrysalis of butterflies is usually attached to a plant or other object, and it is not enclosed in a cocoon. (Some species may use silk to fold a leaf together, then enter metamorphosis in the tentlike shelter.) (Moth pupae are often wrapped in a silk cocoon, frequently are positioned in leaf litter, and the cocoons often incorporate bits of leaves, twigs, etc.)
    • When does it fly? Butterflies are usually active during daylight hours. Some species are most active at dusk and dawn. (Most moths are nocturnal, but there are exceptions.)
    • Butterflies often have relatively thinner bodies than moths, though members of the skipper family of butterflies have thicker, mothlike bodies.
    • The larvae (caterpillars) of butterflies are rarely considered destructive pests, although there are exceptions. (The larvae of several kinds of moths are agricultural and other pests.)
    • Coloration varies greatly, but many butterflies are more colorful than average moths. (There are plenty of exceptions, however!)

    Missouri’s Butterfly Families

    There have been different ways of grouping the butterflies into families. The overview of Missouri’s butterflies, below, follows one system currently in use.

    • Skippers (family Hesperiidae) Small to medium butterflies, fairly drab colored or orangish, usually with relatively large eyes, short antennae with hooked tips, and chunky body. They are named for their skipping flight. Missouri’s skippers can be divided into two groups: spread-wing skippers and grass skippers.
      • Spread-wing skippers typically rest with wings flat and spread to the side this group includes the silver-spotted skipper the cloudywing, duskywing, and sootywing species and the common checkered-skipper — plus others.
      • Grass skippers typically rest with hindwings held flat, parallel to the ground, and forewings positioned upright in a V shape — they look like tiny fighter jets. Missouri’s grass skippers include the Delaware, least, Peck’s, fiery, tawny-edged, and sachem skippers, and several more.
      • Examples include black, eastern tiger, spicebush, giant, and zebra swallowtails.
      • Among the whites, Missouri species include the checkered white, cabbage white, Olympia white, and falcate orangetip.
      • Among the sulphurs, Missouri has the clouded, cloudless, orange, and dainty sulphurs, the southern dogface, the sleepy orange, the little and Mexican yellows, and more.
      • Blues can be tiny with reflective blue on the upperside.
      • Coppers are similar but with reflective copper color.
      • Hairstreaks are usually gray or tan but have ornate (“hair”) streaks on the underside and have slender antenna-like tails on the hindwings.
      • The one harvester species on our continent is a small orangeish butterfly whose caterpillars prey on woolly aphids.
      • Many familiar butterflies are in this family: the monarch, fritillaries, checkerspots, crescents, anglewings (commas, question mark), leafwings, mourning cloak, buckeye, red admiral, ladies, red-spotted purple, viceroy, American snout, the emperors, and satyrs and wood-nymphs. In the past, the subfamilies of this large family have been treated as separate families.
      • Scales on wings
      • Antennae thin with clubbed tip (in skippers, also hooked)
      • Wings usually held open, or held closed together straight above the back
      • Chrysalis (not a cocoon), usually attached to a plant or structure
      • Usually active during daytime
      • Relatively thin body (skippers, however, are chunkier)
      • For in-depth identification, it helps to learn the names of a butterfly’s body parts, including the various regions of the wings (dorsal and ventral, as well as basal, median, postmedian, submarginal, marginal, costal, apical, subapical, and so on).

      Where do you find butterflies? Nearly anywhere, but here are some hints:

      • Butterflies typically fly near their host plants — the specific types of plants a species must lay eggs on, because their caterpillars can only eat that certain type of plant. Cabbage butterflies, for instance, lay eggs on cabbage and other members of the mustard family. Look for males perching or patrolling near the host plants, awaiting females to fly near.
      • Butterflies are often seen at nectaring or puddling sites: amid flowers, where they obtain nectar, or on mud, wet sand, or other damp ground where they obtain moisture and nutrients. Many butterflies visit rotting fruit, tree trunks where sap is oozing out, animal dung, or carrion for moisture and nutrients, too.

      Butterfly conservation involves the same issues as many other animals, chiefly centering around habitat disruption and loss. While many butterflies can live on a wide variety of plant hosts, others can only survive on very particular plant species, which occur in specific native habitats, such as high-quality tallgrass prairie. Another factor is the number of broods: some butterflies lay eggs all spring, summer, and fall, while other species never produce more than a single brood each year. Also, as with other insects, butterflies can be killed by indiscriminate use of pesticides. Another issue involves migratory butterflies, such as the monarch, whose survival depends on having appropriate food plants and nectar sources in all the places they must travel through.

      If you really get into butterflies and skippers, then you will end up learning basic plant identification. Different butterfly species have their own host plants, which the caterpillars must eat in order to survive. A famous example is the monarch, which lays eggs on milkweeds, and the caterpillars eat the milkweed leaves and flowers.

      Butterfly guidebooks usually include comments on caterpillar host plants. Many species have their larval food plants built into the name, such as the hackberry emperor and spicebush swallowtail. Some other host plant associations include:

      • The larvae of various fritillary species eat violets.
      • The Phaon crescent’s larvae eat northern fog fruit.
      • The red admiral’s larvae eat various types of nettles.
      • The host plants for satyrs, pearly-eyes, and wood-nymphs are usually different kinds of grasses.
      • The zebra swallowtail’s larvae eat pawpaw leaves.

      As adults, many buttterflies don’t live very long. Nearly all their growth occurs when they are caterpillars. The adults, therefore, generally only need moisture and nutrients to keep them going: nectar, rotting fruit, or tree sap, for sugar and energy salts and other minerals from mud puddles, damp stream banks, animal dung, and carrion. Different species focus on different nutrition sources. Some butterflies do not visit flowers.

      Statewide. Different butterflies occur in different habitats, which usually correspond to the locations of their larval food plants.

      Several Missouri butterflies and skippers are listed as Species of Conservation Concern, including the regal and Diana fritillaries, northern and swamp metalmarks, Appalachian eyed brown, Ozark woodland swallowtail, Linda’s roadside skipper, Duke’s skipper, and Ottoe skipper. Habitat loss, degradation, and fragmentation are the primary issues.

      Butterflies, like beetles, bees, and flies, undergo complete metamorphosis: after a series of wormlike juvenile (larval) stages, they enter an inactive phase called a pupa, then emerge as sexually mature, winged adults. (Other insects, such as grasshoppers and true bugs, have juvenile stages that look more or less like the adult form, only smaller and minus the wings — their life cycle is called incomplete metamorphosis.)

      Butterflies begin life as eggs that are typically laid on or near the host plant. The larvae (caterpillars) hatch from the eggs and begin eating and growing. As they grow, caterpillars repeatedly molt into larger exoskeletons (“skins”). Each stage is called an instar. Most butterfly caterpillars have four or five instars, and sometimes these can look different with each molt.

      The final juvenile stage is the pupa, which in butterflies is called a chrysalis. The chrysalis hangs from the tip by a silk pad, with hooks at the tip of the abdomen gripping the silk. Swallowtails, whites, and sulphurs also spin a silken sling that surrounds the chrysalis for additional support. Skippers often spin silk onto a leaf, causing it to fold over, then the pupa is attached inside this little shelter. The chrysalis of many butterfly species starts off green, then turns brown, especially if this is the stage in which they overwinter.

      Different butterfly species overwinter at different points in the life cycle: some overwinter as eggs, some at different points in the caterpillar development, and some as the chrysalis. A few overwinter in sheltered places as mature, winged adults.

      People love butterflies. They’re beautiful, and they delight us in ways other insects do not. They figure into poetry, song, literature, art, philosophy, religion, and more. If you love butterflies, there are many ways to increase your enjoyment:

      • Butterfly gardening: Plant native species that are eaten by butterfly caterpillars, and plant flowers that provide nectar for butterflies.
      • Butterfly watching: it’s a real thing, and a lot like bird watching plenty of information is online.
      • Rearing caterpillars: you’ll need to set up your enclosure carefully and make sure the larvae have appropriate moisture and the correct food plants. You can find instructions online. Kids love this activity!
      • Butterfly photography is challenging and rewarding. It becomes a sort of sport.
      • Collecting butterflies: decades ago, this was more popular, but many people today are not so interested in capturing, killing, and pinning specimens, and recording the many detailed field notes that make the collections scientifically meaningful. Still, many serious amateurs do this.
      • Butterfly organizations: there are several you can join, increasing your knowledge while having fun with friends.
      • “Citizen science” opportunities: participate in groups like Monarch Watch, a tagging program that helps scientists better understand monarch populations and habitats. Another program, at Iowa State University, encourages people to report sightings of red admirals and painted ladies, which, like the monarch, are also migratory.
      • Certain butterfly species that overwinter as adults may benefit from “butterfly houses,” which have narrow vertical openings where butterflies can take shelter.
      • Finally, learn about conservation issues and play a role in helping Missouri’s native habitats and species.

      Many butterflies play important roles as flower pollinators, but most of the feeding in a butterfly’s life is done in the caterpillar stage. Nearly all butterfly caterpillars are herbivores, eating leaves, stems, flowers, fruits, and other parts of plants.

      Butterflies play an important role early in the food chain, converting nutrients from plants into their own bodies, which then become food for other animals. Usually, only a small fraction of butterfly eggs survive to become adult butterflies.

      A wide variety of predators are ready to consume a butterfly during all stages of its life — egg, caterpillar, chrysalis, and adult. Butterfly predators include spiders, predaceous insects, fish, amphibians, reptiles, mammals, and birds.

      Butterflies are also eaten by parasitoids. Parasitoid insects are usually wasps or flies that lay their eggs on (or in) butterfly eggs or caterpillars the parasitoid larvae hatch and eat the caterpillar from within.

      Elaborate camouflage, and deceptive eyespots, false antennae, and warning colors are ways that butterflies deter or deflect their predators.

      Several types of butterflies eat toxic plants as caterpillars and therefore become toxic themselves. These species typically have distinctive bright colors, which predators — sickened once or twice — learn to avoid. Monarchs, which eat milkweeds, are an example. Then, other species, which may not be toxic at all, can have colors that mimic the toxic species, and gain some protection from “educated” predators. Warning systems can develop in which a number of toxic, distasteful, or perfectly edible species develop the same warning coloration. For example, several swallowtails in Missouri mimic the black coloration of the acrid-tasting pipevine swallowtail.


      Watch the video: CATERPILLAR CARE. oleander hawk moth daphnis nerii (January 2022).