Friday, February 27, 2015

Long-tailed Dance Fly

Dance flies are a very diverse group of predatory flies mostly feeding on other flies. They often gather in 'dancing' swarms you can see backlit in forests and meadows, though many other fly groups show the same behaviour.

Much more unusual is the practice of 'gift-giving' by males of some species. They bring a dead insect to the female for her to dine on while they mate. Some species even wrap their gift in a silken cocoon and believe it or not, in some of those species shifty males offer empty cocoons.  Females of the Long-tailed Dance Fly (Rhamphomyia longicauda) are completely dependent on male food gifts for nourishment. Since males bring prey only to females they think have eggs, females inflate sacs in their abdomen to appear egg-laden even if they don't have any.

Thursday, February 26, 2015

Ground Crab Spider

Crab spiders got their name from the resemblance to crustacean crabs as they walk and and when they sit at rest. Their crab-like appearance comes from the longer sets of front legs than back legs. Ground Crab Spiders (Xysticus ellipticus) are able to walk sideways and backwards and of course forward.

Usually they sit on flowers and leaves waiting for their prey. Butterflies, bees, beetles and flies are their victims. The strong front legs are used to grab the insect which is then quickly bitten and paralyzed. 

The Ground Crab Spider does not belong to the spiders which build webs to trap their prey. The spiders of the entire crab spider family are not known to be harmful to humans.

The females lay their eggs in silken sacs that they guard until the little spiderlings hatch.

Tuesday, February 24, 2015

Flower longhorn beetle

Longhorn Beetles (Family Cerambycidae) have antennae that are as long or even longer than their entire body. They spend their larval life boring in wood. Some of the species can cause damage to live trees. Other species primarily bore into dead or down trees. The adults leave their protective tunnels and fly to find food, mates and colonize new trees.

Strophiona nitens is one of the so called flower longhorn beetles that frequently visits flowers to feed on pollen and nectar. The beetles do not damage the flowers. They contribute to the festive nature of a butterfly garden. Our insect of the day has distinctive black and yellow bands on its elytra (cover wings). A beautiful little beetle with many natural enemies, especially parasitic wasps and the larvae of certain other beetles. Many birds feed on adults and woodpeckers are fond of the larvae. Lizards sometimes lie in wait and capture adults when the beetles land on bark to mate or lay eggs.

Monday, February 23, 2015

Silver longjawed orbweaver

Long-jawed Orb Weavers are named because of their large chelicerae (fangs), which are, in some species, longer than the spider's cephalothorax (the fused head and thorax of spiders). This family and another one called true orb-weavers are the only kinds of spiders that make orb webs. The webs of most other kinds of spiders appear disorganized compared to orb webs.

Spiders like todays species (Tetragnatha laboriosa) build their webs in strategic locations to catch flies, moths, and other insects.  Birds and other small animals often eat these kinds of spiders. They are very common in tree branches that overhang lakes and streams.  Often, a long-jawed orb weaver will remain still in its web so that you can take a good picture.  If you are interested in collecting one of these spiders, remember that they can bite and should never be handled, although they aren't typically dangerous.

Friday, February 13, 2015

Handsome Fungus Beetle

Handsome fungus beetles (Endomychidae) are a family of beetles with representatives found everywhere on earth. There are about 1300 known species. One of the North American representatives is Phymaphora pulchella, a tiny insect (3-4mm long) with a dark spot above its head, and another dark band across its back. It has yellow legs and antennae, and the particularly ‘handsome’ males have antennae with swollen tips.

As said handsome fungus beetles occur all over the world, but this species is native to North America. These beetles feed on fungus that grows under the bark of trees. Phymaphora pulchella is most commonly collected at fresh wounds in trees, although the reason for that is still a mystery to entomologists.