An online resource based on the award-winning nature guide

July

Robber Fly Mimics Bumblebee

8-4-14  robber fly like bumblebee2 054Milkweed leaves make excellent platforms for all kinds of insects, particularly those such as dragonflies and robber flies, which sit, wait and watch, surveying the landscape for prey to ambush. This robber fly could quite easily be mistaken for a bumblebee. However, the short, straight antennae and the presence of only two wings (instead of four) tell you it’s in the order Diptera (true flies). The pointed, stout proboscis, bearded face, fleshy feet and long, tapering abdomen narrow it down to a species of robber fly. Robber flies in the genus Laphria resemble bumblebees – they are typically quite hairy, with black bodies and yellow stripes on their abdomens. Like other species of robber flies, they hunt by perching and snagging prey such as other robber flies, bees, wasps or beetles. They often return to their perch, inject the prey with enzymes that dissolve its innards, and then have a long drink. Why mimic a bumblebee? To deceive unsuspecting honeybees, wasps and other insects that would make a good meal.

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Tortoise Beetle Larvae Making Fecal Shields

8-1-14  tortoise beetle larva with fecal shield 049Instead of discarding feces, or frass, some insects save their waste matter for defensive purposes such as “fecal shields.” These are coverings over the back of the larvae that are made largely of feces and provide either physical or chemical barriers to predation. Adult Tortoise Beetles have a type of shield (hence, their name), but it is formed from expanded, hardened forewings, and is not a fecal shield. The larvae of these beetles have fecal shields which serve as chemical deterrents, preventing most predators from even touching them. The deterrent in the feces comes from the beetles’ food source — plants in the order Solanales. Tortoise Beetle larvae have what is known as a “fecal fork” on their last abdominal segment, which they hold over their body. The larvae maneuvers its muscular, telescopic anus, or “anal turret” in such a manner as to excrete its feces and bits of shed exoskeleton onto the fecal fork, forming an umbrella-like fecal shield.

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Black-throated Blue Warblers Incubating Second Brood

8-1-14 -female black-throated blue warbler on nest 054Male and female Black-throated Blue Warblers differ strikingly in appearance, so much so that the two sexes were considered separate species by early naturalists, including John J. Audubon. While the male is a brilliant blue, the female is dull gray which makes her practically invisible when she’s on a nest.

Black-throated Blue Warblers have anywhere from one to three broods in a summer, the first usually in June, a second, if there is one, in July and rarely a third in late July or early August. The nest is usually within three feet of the ground, and is built out of thin strips of birch bark and bits of rotten wood bound together by cobwebs and saliva. Fibers, rootlets, needles and mammalian hair line the nest. Female Black-throated Blue Warblers are known for sitting tightly on a nest until a potential threat is very close, at which point they drop to the ground, and, similar to Killdeer, engage in a distraction display, feigning injury to their wing.

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Common Wood Nymphs Mating

7-28-14 mating common wood nymphs 066If you’ve walked in a shrubby meadow lately, you are probably well aware that Common Wood Nymphs (Cercyonis pegala) are everywhere. Each step seems to flush one, which, after some erratic flying, settles back down beneath the grasses, hidden from view. These butterflies are in a group called “satyrs” which consists of mainly medium-sized, brown butterflies. They belong to the Nymphalidae family, also known as brush-footed butterflies, or four-footed butterflies. The reason for these common family names is immediately apparent when examining a Common Wood Nymph (or Monarch, Painted Lady, fritillaries or checkerspots). Butterflies in this family look as though they only have four feet. Being insects, however, they have six. The front two legs are folded up in front of its head, and are extremely small and bristly. These reduced legs are present in all brush-footed butterflies, and are not used for walking or clinging. Rather, the bristles on these legs are sensory organs, used for detecting smells and for tasting. The butterfly’s proboscis is coiled up between this front pair of legs.

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Bunchberry Fruiting

7-24-14 bunchberry fruit IMG_8240Bunchberry, Cornus canadensis, is among the smallest of a genus of mostly shrubs and trees, and the only dogwood species that is herbaceous. The white flowers (resembling one flower, but actually consisting of many flowers , each 2 mm in diameter, surrounded by four modified leaves, called bracts) develop into red fruits which some people and a few birds, including ruffed grouse, veeries and vireos, find tasty. Bunchberry prefers cool, acidic soil — look for it where you find partridgeberry, goldthread and twinflower. If you find it, look closely, as Nashville warblers sometimes nest beneath it.

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Twelve-spotted Tiger Beetle Larva at Work

7-24-14 tiger beetle adult and larva 040Without doubt, I have one of the most erudite readerships in the land of blogs. Several people recognized this uncommon phenomenon. To clear up a few misconceptions, however, being a male, this dragonfly was not laying eggs. Neither was it fertilizing them – male dragonflies perform this act when coupled with a female. This Chalk-fronted Corporal had the misfortune to sun itself on a tiger beetle-inhabited patch of sand. One of the most aggressive groups of insect predators is the tiger beetle family. They are especially known for their speed – up to 5.6 mph, which is comparable to a human running 480 mph. If you watch an adult tiger beetle hunting, you’ll notice that it stops and starts frequently. This is because it runs so fast it goes blind — its brain has trouble processing the information it sees, and the beetle must stop to regain its sight.

The larvae of the Twelve-spotted Tiger Beetle live in tunnels that they dig in the sand (some of you noticed tiny holes near the dragonfly) that can be up to a foot deep. The larvae have hooks located on the back of their abdomen to anchor them to the side of the burrow. Tiger beetle larvae are also predators, and after digging a tunnel the Twelve-spotted Tiger Beetle will crawl up it until just the top of its head is visible. From this position the larva watches for prey wandering by. When it sees a potential meal, such as yesterday’s dragonfly, it flips backwards faster than you can blink an eye and grabs its prey, pulling it down as far as it can into its tunnel, where it safely feasts on its catch. The portion of the Chalk-fronted Corporal’s abdomen that was inside the tiger beetle tunnel was completely consumed except for the outer skeleton.

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Least Sandpipers Migrating

7-22-14 least sandpiper IMG_7923Least Sandpipers are the smallest shorebirds in the world, weighing only an ounce and measuring 5 – 6 inches long. Their fall migration has already begun, with individuals leaving their breeding grounds in the subarctic tundra and far northern boreal forest for their wintering grounds in Central and South America. Banding has revealed that the eastern population of Least Sandpipers undertakes nonstop transoceanic migrations of about 1,800 to 2,500 miles from the Gulf of St. Lawrence and New England to northeastern South America. Not much bigger than a sparrow, this common but declining shorebird can be seen refueling on mud flats throughout New England during its fall migration.

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