An online resource based on the award-winning nature guide

Posts tagged “Invertebrates

Twelve-spotted Skimmers

Twelve-spotted Skimmers are classified as “King Skimmers,” all members of which are large and conspicuous, often with distinctive wing patterns.   Male Twelve-spotted Skimmers (pictured) have a grayish bloom on their abdomens and each wing has three dark spots with white spots in between them.  Females have brown abdomens and no white spots on their wings.  All summer you can see males flying back and forth short distances along the shores of ponds and over water, hovering as well as perching.  They are territorial and patrol over water, loop-de-looping with competing males.  A small number of Twelve-spotted Skimmers occasionally take part in Atlantic Coast migrations.


American Lady Larva

The American Lady larva is very distinctive with its branched spines and white bands across its abdomen.  One of its favorite foods is Pussytoes, a member of the Aster family.  The larva feeds inside a shelter it makes by tying up several leaves with silk.  In the photograph, the larva has incorporated the flower heads of Pussytoes into its shelter.  Not only is the larva feeding and growing inside this 1 ½ ”-long  cavity, it also shed its skin.  To see an adult American Lady butterfly, go to https://naturallycuriouswithmaryholland.wordpress.com/2012/07/08/american-lady-common-milkweed-pollinia/ .  Soon after the larva forms a chrysalis and pupates, a butterfly emerges and starts its migration south for the winter.


Earwigs

People used to believe that earwigs crawled into people’s ears while they were sleeping and proceeded to bore into their brains, thereby causing insanity and/or death. Fortunately, this isn’t, and never has been, true. Earwigs feed on leaves, flowers, fruits, mold and insects, but not human brains. Because they are nocturnal, during the day we often find them secreted away in some dark, damp crevice, often on a plant. These flat, elongated insects have a pair of pincers, or cerci, at the end of their abdomen which they use to capture prey, defend themselves and arrange their hind wings, if they have them. (Earwigs that possess wings can, but rarely do, fly.) You can actually determine the sex of an earwig, should you be so inclined, by the shape of its cerci – those of a male (pictured) are unequal in length, strongly curved and larger than the straight cerci of females.


Ant Mandibles

Ants go through complete metamorphosis, passing through four stages (egg, larva, pupa, adult). Like honeybees, there are queens, female workers and male drones in an ant colony. The female worker ants have a series of “jobs” that they perform in a certain order. A young worker spends the first few days of its life caring for the queen and young. After that she maintains the nest and eventually forages for food. Like most insects, ants lack grasping forelegs and compensate for this by using their mandibles as “hands.” When the nest is disturbed, workers rush to rescue the eggs, larvae (depicted in photograph) and pupae by clasping them in their mandibles and transporting them to safety. They also use their mandibles to carry food, construct nests, and for defense.


Common Milkweed Pollination

This slideshow requires JavaScript.

The structure of the Common Milkweed (Asclepias syriaca ) flower is such that its pollen, produced in two saddlebag-like sacs with a black appendage joining them, snaps onto an insect’s leg when the two come in contact with each other. To assure that the chances of this are high, the pollen sacs (pollinia) hang inside a slit that is located between each of the five cups, or hoods, that contain nectar. An insect lands on the slippery flower, attracted by both the scent and availability of nectar, and inadvertently one or more of its six legs slips down between the hoods into a slit, where the pollinia automatically attach to the leg. The insect withdraws the leg upon leaving to find more milkweed nectar, and the attached pollinia eventually falls off onto another milkweed flower, pollinating it. Unfortunately, about 5% of milkweed flowers visited trap insects because they cannot extract their legs from the slit. It is not uncommon to see an insect dangling from a Common Milkweed flower – during a 30 minute visit to a milkweed patch recently I released 2 flies, 3 skippers (butterflies) and one honeybee that were caught, but hadn’t yet perished.


Broad-necked Root Borer

This impressive egg-laden, 2-inch long female Broad-necked Root Borer (Prionus laticollis) was attempting to lay her eggs when I discovered her. She repeatedly extended and retracted her ovipositor (pointed, egg-laying structure at tip of abdomen) in an attempt to probe the packed dirt in my driveway, but finally moved on to softer soil. Female Broad-necked Root Borers insert clumps of eggs into the ground. When the eggs hatch, the larvae tunnel downward to feed on the roots of a variety of shrubs and trees. In the spring they pupate, and adults, such as this female, emerge. This whole life cycle is thought to take three years.


Red Grasshopper Mites

The next time you’re in a field, stop and take a close look at a few of the grasshoppers you find there. Chances are great that you will see tiny, red mites on some of them. These Red Grasshopper Mites, close relatives of ticks and spiders, go through three stages: larva, nymph and adult. The larvae (6-legged) attach to the base of a grasshopper’s wings, where they suck the grasshopper’s blood. The nymphs and adults (both 8-legged) are free-living and feed on grasshopper eggs. Each Red Grasshopper Mite nymph requires more than two grasshopper eggs to become an adult. An adult male Red Grasshopper Mite requires three grasshopper eggs for reproducing, and each female, seven to eight eggs. After breeding, a female mite deposits up to 4,000 eggs. Entomologists believe that mites reduce grasshopper survival and reproduction dramatically.