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!
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.
The Viceroy Butterfly closely resembles the Monarch Butterfly, but is smaller, and has a black line that runs across the veins of its back wings, which the Monarch lacks. While Viceroys don’t contain the poisonous cardiac glycosides that Monarchs do, they do contain salicylic acid due to fact that the larvae feed on willows. This acid not only causes the Viceroy to taste bad, but makes whatever eats it sick. So not only do these two butterflies look alike, but they discourage predators in the same way. This is not a coincidence. The fact that they are both toxic if eaten and are preyed upon by some of the same predators has led to their similar appearance. This phenomenon is referred to as Müllerian mimicry, and essentially it means if two insects resemble each other, they both benefit from each other’s defense mechanism — should a predator eat one insect with a certain coloration and find it inedible, it will learn to avoid catching any insects with similar coloration.
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 )
If you’ve been traveling on sunny dirt roads lately, chances are that you have seen White Admiral butterflies all over them. They are in the road to obtain salts and minerals that have leached from the soil into standing puddles and moist dirt. Because butterflies do not have chewing mouthparts as adults, they must drink their meals. While nectar is their main source of nutrition, males often supplement their diet with these minerals. The act of acquiring nutrients in this manner is referred to as “puddling.” If there’s no water around, a butterfly may regurgitate into the soil and then drink in the hope of retrieving minerals. In addition to finding butterflies on dirt roads, look for them puddling on animal scat.
The male Eastern Tiger Swallowtail butterfly (pictured) is yellow with four “tiger stripes” on each of its forewings. The female can be yellow or black, and has more blue on the hind wings than the male. Eastern Tiger Swallowtails are currently mating and laying eggs on plants which their larvae eat, which include black cherry, red maple and American hornbeam. When the caterpillars first hatch, they resemble bird droppings – an effective way of decreasing predation. As they get older, the larvae turn green and have a large head and bright eyespots.
With the warm temperatures this week, mourning cloak butterflies have been seen gliding through the leafless woods. Like eastern commas, question marks and red admirals, mourning cloaks overwinter as adults. They resemble dead leaves so much that from a distance the entire insect seems to disappear. Up close you can see the velvety texture of the wing scales, said to resemble the clothing mourners used to wear; hence, their common name. Mourning cloaks live up to ten months — an impressive life span for a butterfly. As they age, the yellow border of their wings fades to an off-white.
It’s hard to believe, but even after Irene, several inches of snow and an occasional night that’s below freezing, there are still butterflies and moths to be seen. Yesterday this sulphur butterfly (probably clouded, Colias philodice) was flying from dandelion to dandelion, sucking up nectar with its long, black proboscis. Clouded sulphur and orange sulphur butterflies, two different species, are similar looking, and on top of that, they even hybridize, so distinguishing between the two is often difficult, at best. Both species have several broods in a summer; you can see them flying in fields and along roadsides from spring to fall.
We think of monarch larvae as being impervious to the ills of milkweed, but they are very vulnerable when it comes to the sticky latex in the sap of their host plant. The mandibles of young monarch caterpillars are often glued together by this latex, preventing them from eating. Research shows that about 30 percent of monarch larval loss results from miring in this glue-like substance. One strategy young larvae use is to chew a near circle in a milkweed leaf, blocking the flow of latex to the enclosed surface area, which they then eat. If a monarch survives the first few stages, or instars, of its larval life, it uses yet another strategy to circumvent the latex. Older, larger larvae often cut through the midvein of a leaf they wish to consume, which dams the latex flow to the entire leaf beyond the cut. Look for limp leaves as you peruse a milkweed patch. If you find one, you may be rewarded with the nearby presence of a monarch caterpillar.
Unlike spiders, whose spinnerets, or silk-spinning spigots, are located at the tips of their abdomens, caterpillars’ spinnerets are located underneath their heads. The most prominent white structure with a black band around it is the monarch caterpillar’s spinneret, in which its silk glands are located. The smaller structures are called maxillary palps and are antennae-like sensory devices. Prior to metamorphosing into a chrysalis/pupa, the monarch caterpillar draws silk through its spinneret, and forms a small, well-anchored button of silk. The caterpillar clasps this button with a structure called a cremaster, located at the tip of its abdomen, from which it suspends itself upside down. Soon thereafter its skin splits, revealing a gold-dotted, green chrysalis from which an adult monarch butterfly will emerge in two weeks.
This 15-minute-old monarch butterfly that emerged yesterday will live for 2 to 5 weeks, long enough to mate and produce the next generation of monarchs. The generation of monarchs that emerges a month or more from now will live six to nine months, and not mate until next March or so – after flying to one of about a dozen locations in the Transvolcanic Mountains of central Mexico (a flight of up to 3,000 miles) and spending the winter. Late summer-emerging monarchs live longer than monarchs that emerge earlier in the summer because they do not immediately expend energy on breeding and the cool winter temperature in Mexico slows their metabolism, allowing them a longer life.
Five years ago the U. S. Senate designated the last week of June as “Pollinator Week” in honor of all the bees, bats, butterflies, beetles, birds and other creatures responsible for transporting pollen from one plant to another plant of the same species for over 75% of all flowering plants (wind does most of the rest). In the U.S. pollination produces nearly $20 billion worth of products annually – think chocolate, almonds, apples, coffee, blueberries, etc.