An online resource based on the award-winning nature guide

Insects

Fire-colored Beetle Larvae

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Peek under the loose bark of rotting logs, both deciduous and coniferous, and you’re bound to find the larva of a beetle known as a Fire-colored Beetle (family Pyrochroidae).  Its common name is derived from the Greek word pyros (“fire”) + chroma (“’color”), a reference to the bright color, often red, of the adults of some species.   From one to several years are spent in the larval stage. Adults of the Pyrochroinae emerge from late spring to midsummer and are primarily nocturnal.

Many adult Fire-colored Beetles are attracted to cantharidin, a toxic compound produced by Blister Beetles.  Males locate a Blister Beetle, climb onto it and lick off the cantharidin that Blister Beetles exude and use the blistering agent to impress a female of their own species. When mating takes place, most of the cantharidin is transferred to the female in the form of a sperm packet.  The eggs the female subsequently lays are coated with cantharidin to protect them from being eaten before they hatch. (Bugguide.net)

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Woolly Bears Seeking Hibernacula

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The Isabella Tiger Moth typically has two broods during the summer.  The caterpillars (Woolly Bears) in the first brood pupate and emerge as adult moths mid-summer.  The second brood overwinters as caterpillars and pupate in the spring.  The Woolly Bears we see crossing roads at this time of year are second-brood caterpillars in search of protective hibernation sites (hibernacula).

Old-timers predicted the severity of the coming winter by the relative lengths of the black and brown bands of the caterpillars when they became easy to observe in the fall – the longer the black sections and narrower the brown section, the harder a winter they were in for.  In fact, this may have had some validity, as brown hairs (setae) are added to the middle band every time the caterpillar molts. Therefore, the older the caterpillar, the wider the brown band.  If winter comes early, the caterpillar’s brown band would be relatively narrow due to the fact it didn’t have time to mature fully and develop a wider brown section before hibernating.

The adult stage of the Isabella Tiger Moth is often overlooked, due to the appeal of the larval stage.  This tan moth, with a wingspan of 1 ½ – 2 inches, has tiny black markings on its wings.  Male and female are sexually dimorphic and can be distinguished by the color of their hind wings.  Males have yellow-pale orange hind wings while the hind wings of females are rosy. (Photo:  Woolly Bear; photo inset: female Isabella Tiger Moth)

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Stinkhorns Maturing

10-5-18 dog stinkhorn IMG_9973There are a group of fungi known as stinkhorns — aptly named, as their foul odor can be detected even by the human nose. All stinkhorns first appear as an “egg” which can be up to two inches high. When the eggs rupture, the appearance of the different species of fungi in this family (Phallaceae) can differ dramatically, but many have a phallic-like shape. At maturity, all stinkhorns produce an olive-green to olive-brown slimy substance that has a putrid smell (to humans), but is very appealing to many insects.  This slime is loaded with the fungi’s spores. Insects landing on a stinkhorn get their feet covered with the spore-laden slime while they are busy ingesting it.  Once the insects depart, the spores are dispersed far and wide.

Stinkhorns appear suddenly, and their growth can almost be observed, as they go from the egg stage to maturity with impressive speed. While these fungi are not poisonous, it is doubtful that having smelled them, anyone would desire to eat them.  (Photo:  Dog Stinkhorn aka Devil’s Dipstick, Mutinus caninus)

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Grasshoppers Laying Eggs

10-3-18 grasshopper_U1A0275Being cold-blooded, a female dew-covered grasshopper, plump with eggs, basks on a cold morning in the early morning light in order to warm her muscles up enough to allow her to jump down to the ground below.  She then inserts her abdomen into the ground with the help of an egg-laying organ called an ovipositor that is shaped like a knife, and proceeds to dig down an inch or two. It is here where her eggs will spend the winter, clustered together in a protective case of hardened foam (pod) that the grasshopper secretes while laying her eggs.  While most males perish soon after mating, females have a longer life, not dying until after laying their eggs in the fall.

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Black Blister Beetles Consuming Asters

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Blister beetles are so-called because they contain a chemical in their hemolymph, or blood, called cantharidin.  If rubbed or pressed the beetles release cantharidin as a defense mechanism, which causes blistering on human skin.  The Black Blister Beetle (Epicauta pennsylvanica) belongs to a genus of beetles that are highly toxic to horses — a few beetles fed in a single feeding of alfalfa can be lethal.

As larvae, most blister beetles are predators, often invading wild bee colonies and consuming bee larvae, as well as nectar and pollen.  Black Blister Beetle larvae and other blister beetles in the genus Epicauta prey on the eggs of grasshoppers.  Female Black Blister Beetles lay clusters of eggs in the soil in late summer. The small, active larvae that hatch from these eggs crawl over the soil surface entering cracks in search of grasshopper egg pods which are deposited in the ground. After finding an egg mass, the blister beetle larvae become immobile and spend the rest of their developmental time as legless grubs. The following summer they transform into the pupal stage and soon emerge in the adult stage. This is why blister beetle numbers increase dramatically following high grasshopper populations.

Once they mature into adulthood, Black Blister Beetles feed on plants (phytophagus) and are commonly found on flowers, especially those in the Aster/Composite family. They are said to be there for the nectar and pollen, but the Black Blister Beetle pictured denuded several aster blossoms of all petals during the time it was observed.

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Fall Webworms

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For several weeks white webs on the tips of branches have been apparent on many trees.  These silken tents are the work of the Fall Webworm (Hyphantria cunea), a moth most associated with its larval stage. Fall Webworm caterpillars construct a web over the end of a branch, enclosing leaves on which they feed.  As the hairy, white caterpillars grow, they enlarge the web to encompass more leaves, with tents sometimes extending two to three feet.

Often mistaken as the work of Eastern Tent Caterpillars, the tents of these two moths can be distinguished by the season they appear (ETC are active in the spring, Fall Webworms in the fall) as well as the location of the tents (ETC are usually in the crotches of trees, Fall Webworms at the tip of branches). As soon as the eggs hatch in early summer, the Fall Webworm larvae begin to spin small silk webs over the foliage of the deciduous trees on which they feed (over 90 species). By fall the tents are conspicuous. A look inside one  reveals caterpillars, dead partially-eaten leaves, and fecal droppings.

The larvae feed together inside the increasingly large web for roughly six weeks, at which point they often start feeding independently before pupating in the ground over the winter and emerging as adult white moths the following summer.

If your favorite tree has one or more Fall Webworm nests in it, there’s no cause for alarm. These caterpillars may defoliate a tree occasionally, but rarely kill it, and usually only build tents on a handful of branches, if that. The larvae have more than 50 natural predators and 36 parasites that help control them. Also bear in mind that Fall Webworms do not eat the buds of next year’s leaves and the leaves they are feeding on will soon to drop to the ground. Next year leaves will appear on the currently affected branches with no sign of last year’s damage.

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Second Brood of Snowberry Clearwing Moths In Flight

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Clearwing moths are strong and fast fliers with a rapid wingbeat, like the other members of the Sphingidae family. Most species in the group are active at dusk and feed much like hummingbirds, hovering in front of a flower and sipping nectar through their extended proboscis.  In most species, the larval stage is called a “hornworm” because the caterpillar’s posterior end has a horn-like appendage protruding upward.

Like its close relative, the Hummingbird Clearwing (Hemaris thysbe), the Snowberry Clearwing (Hemaris diffinis) is a day-flying moth, has transparent wings and is a mimic.  While they both hover at flowers, the Hummingbird Clearwing is said to mimic a hummingbird, while the Snowberry Clearwing is considered a bumblebee mimic.  To distinguish these two clearwings, if it has black legs and a black band that crosses the eye and travels down the side of the thorax, it’s a Snowberry Clearwing.

In addition to thistle, adult Snowberry Clearwings feed on honeysuckles, snowberry, hawkweed, lilacs and Canada violets. (Thanks to Barbara and Knox Johnson for photo op.)

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