Like all adult wasps, bees, and ants, adult paper wasps are limited to liquid diets – they have no chewing mouthparts, and the passageway between their head and abdomen, where food is digested, is so narrow that pieces of food wouldn’t fit through it. Wasp larvae (the white grub-like organisms in the upper third of the pictured wasp nest cells) are able to eat a wider range of food, due to mouthparts and their body structure. Adult paper wasps capture and feed caterpillars and other insects to their larvae. The larvae then digest their food and produce saliva rich in nutrients. The adult wasp proceeds to scrape her abdomen across the nest, producing a vibration that signals to the larvae to release some of their carbohydrate-rich saliva which the adult then drinks. (Cells covered with white paper nest material contain wasp pupae.)
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Abbott’s Sphinx Moth larvae feed on grape and Virginia creeper leaves during the night. During the day they tend to rest on the woody vines of the plants they are eating, and because they are well camouflaged, they remain hidden from most humans’ eyes. Both as larvae and adults, these moths are well equipped for survival. Older larvae have two color forms, one resembling unripe green grapes (in photo), and the other is brown and looks much like a branch. In their last stage, or instar, both forms have a rear eyespot which looks like a human eye, right down to the white reflection spot in it, which scares off potential predators. If the caterpillar is pinched or prodded, it squeaks and tries to bite the attacker. The adult moths, which emerge next summer after pupating all winter, also defend themselves with both color and behavior. They are brown with yellow bands on their underwings, which make them look something like a bumblebee, and when they fly, they create a buzzing noise. (Thanks to Heidi, Tom and Simmy Wetmore for photo op.)
The larvae of moths and butterflies are very susceptible to predation, especially by birds, and they utilize many different strategies to protect themselves. Shapes, colors and behavior all contribute to their survival. Some larvae take on the appearance of less appetizing things, such as bird droppings, twigs or leaves. Some have large eye spots which presumably scare predators. Others have cryptic coloration which makes them all but invisible. The pictured green caterpillar uses both color and behavior to visually disappear on the fern it is consuming.
Butterflies in the family Nymphalidae are also referred to as brush-footed butterflies (their front pair of legs are much reduced, brush-like and nonfunctional). Several species of Admiral butterflies belong to this family, and one of the most common in New England is the White Admiral, also known as the Red-spotted Purple. White Admirals overwinter as caterpillars and emerge in late April to feed for several weeks on the young leaves of cherries, willows, poplars and birches, as well as other trees, before forming chrysalises and transforming into butterflies. It is relatively easy to recognize the larva of any species of Admiral butterfly, as they are our only horned bird-dropping mimics. Quite an effective way to discourage predators!
You could hardly be blamed for not recognizing that this bright yellow-green, half-inch-long, oval creature is the larval stage of a moth! Possessing suction cups rather than prolegs, the Yellow-shouldered Slug (Lithacodes fasciola) glides, rather than crawls, over the leaf it is consuming. Perhaps this is why these caterpillars show a preference for smooth-leaved trees and shrubs such as basswood, beech, cherry, maple and oak (although this particular individual was found on a witch-hazel leaf). The Yellow-shouldered Slug pupates inside a cocoon all winter, and in the spring a small, brown moth emerges.
The Spined Soldier Bug is a predatory stink bug which preys on a variety of other insects (over 90 species), especially the larvae of butterflies, moths and beetles. It is one insect that farmers actually welcome, as it preys heavily on the larvae of the European corn borer, Mexican bean beetle, cabbage looper, Colorado potato beetle, flea beetles and many other crop pests. The adult Spined Soldier Bug has a prominent spine on each “shoulder.” It also has piercing-sucking mouthparts which it uses to impale prey and suck out their internal juices. The photograph shows a Spined Soldier Bug dining on the innards of a monarch caterpillar.
Milkweed is in full bloom right now, presenting the perfect opportunity for young and old alike to discover the multitude of butterflies, beetles, bees and other insects that are attracted to these magnificent flowers. If you visit a milkweed patch, don’t leave before getting a good whiff of the flowers’ scent – one of the sweetest on earth. How many of the insects you find are carrying milkweed’s yellow pollen “saddlebags” on their feet? You might want to check out my children’s book, MILKWEED VISITORS, which I wrote after spending the better part of one summer photographing the various insects I found visiting a milkweed patch. ( http://basrelief.org/Pages/MV.html )
Many plants practice “delayed greening” of their leaves, including this Red Maple (Acer rubrum). An initial lack of chlorophyll prevents the leaves from photosynthesizing and making food, which means they have little nutritive value, and thus, appeal, to an herbivore. Most plants that delay greening have reddish leaves due to the presence of anthocyanin, a pigment which appears reddish. A majority of herbivorous insects and invertebrates cannot detect colors in the red range of the color spectrum. Young leaves suffer the greatest predation from invertebrate herbivores. Red leaves would be perceived by these leaf eaters as somewhat dark and possibly dead – not a choice food material. It is possible that the red coloration of new leaves allows the plant to make them unappealing to the herbivores that would otherwise eat them.