Monday, March 23, 2015

Banded Ash Borer

This seems to be the week for longhorn borers as our woodpile came to life on Saturday with dozens of these long-legged, longhorn beauties. I had never seen this particular species before and after inquiring on facebook, one of my friends knew right away that is was a Banded Ash Borer (Neoclytus caprea). Like the Painted Hickory Borer I posted last week, this one is also a wasp mimic which is easy to see why by the image to the right. Their black and yellow (or white) striped markings and long legs are very wasp-like in appearance.Their movements are also erratic like wasps. It was very difficult to get clear images of these beetles as they are very fast moving and prone to flight when you get anywhere near them. I spent well over an hour just trying to get a few passable images. Insect photography will certainly teach you patience....or drive you buggy, not sure which. 

Banded Ash Borers are found throughout Eastern Canada and most of the United States. They use Ash, Mesquite, Hickory, and Elm to lay their eggs in. Rarely do they infest healthy trees, instead they prefer trees that are stressed or dying. Adults emerge early in the spring, typically in April, but obviously as early as March if the weather is warm enough. They will also be found in firewood and emerge from logs in your homes, sometimes in large numbers which can be worrisome if you aren't familiar with them. They are harmless and will not bite, sting or otherwise harm us. They will also not harm your woodwork or furniture. They look for trees or firewood with the bark still intact in order to lay their eggs. If you are overly concerned about finding these beetles in your home, removing the bark from your firewood will solve the issue. 

Females lay their eggs in the cracks or crevices in the bark of host trees or firewood. The eggs hatch and the larvae, called round-headed borers, burrow into the sapwood where they feed until late summer at which time they form pupal chambers in the wood just below the bark and spend the winter in this stage. In the spring the adults emerge and look for mates. They complete one generation per year, but if the female chooses firewood to lay their eggs it may take as long as 2 years to complete their lifecycle.

There are few insects active this time of year, so when warm days bring out pretty beetles like this, it is hard to not get somewhat excited.

Tuesday, March 10, 2015

Painted Hickory Borer

The Painted Hickory Borer (Megacyllene caryae) in the family Cerambycidae, is one of the most frequently misidentified beetles in their range (more about this later). Each spring, usually in March or April this beetle emerges from hickory trees and other closely related trees. In some cases if you burn wood in your fireplace or wood stove you may find one of these colorful beetles flying or crawling through your house as early as January or February. Hickories and Pecans in the genus Carya are the main host tree for this species, but they will also be found emerging from hackberry trees in the genus Celtis. My husband cuts and burns hackberry in our wood stove as well as other species of wood like black locust, hedge and oak. I've found close to a dozen of these longhorn beetles in my house in the past few weeks. They have most certainly come from the hackberry logs since we don't burn pecan or hickory. The one pictured here I took outside and placed on the closest available tree, which happened to be a cherry. I'm sure it will make it's way into our timber where it will find a mate and lay eggs on the hickory trees that are there. We discovered two recently deceased shagbark hickories that will make a great host for them.

                                (For comparison Left: Locust Borer; Right: Painted Hickory Borer)

As I mentioned above these particular beetles are one of the most misidentified beetles in their range. So what beetle are they confused with? Another longhorn beetle called the Locust Borer (Megacyllene robinae) which looks nearly identical to the PHB. So how do we tell the difference? Well it can be difficult, even for experts sometimes, but the easiest way is based on seasons. The Painted Hickory Borer is found in the spring, whereas the Locust Borer is found in the fall. Locust borers are frequently found feeding on goldenrod which blooms in autumn. Their host trees are locust trees as their common name would suggest, especially Black Locust. PHB use trees that are already dead as their host, whereas Locust Borers often use viable, live trees. They are considered a major pest of the Black Locust, but some would say that is a good thing. I know several individuals who consider the black locust tree a pest itself. So I guess the pest classification of the black locust borer is all relative to how you feel about the black locust tree. I don't have an opinion one way or the other about black locust trees. I know their blooms smell fantastic in the spring and when I am hiking in the timber it is a welcome treat in the spring to catch a whiff of their blossoms on the breeze. Not only do they smell wonderful, they are edible too!  Black locust wood burns well as firewood and common enough to be easy to come by. But to many they are thought of as invasive.
Other identification characteristics:  PHB have reddish colored legs which Locust borers do not have. PHB also have yellow and white, broken lines on their wings. Locust borers have wider yellow lines on their wings without breaks in them.Use the above photos to compare the two species and notice the locust borer is on goldenrod....their favorite autumn food source.

                                                            (Do I look like a wasp?)

Both species are sometimes referred to as wasp mimics because of their superficial resemblance to certain species of wasps. One can assume this provides them a measure of protection from predation from potential predators that may not be keen on eating a wasp. After all stings hurt, and a good sting to the mouth would be even more reason to avoid them.

PHB are found in the Eastern United States with records from New Mexico as well. They reach lengths up to 20 mm and are a welcome site to anyone who loves bugs as they are often one of the first species spotted in the spring after a cold, long winter of no bugs. In my case they were a beautiful winter visitor which was fine with me. I know they are harmless and will not bite or chew on any wood furniture or woodwork in my house. 

PHB was first described by a man by the name of Charles Joseph Gahan in 1908. Gahan was born in Ireland and went onto become the Keeper of the Department of Entomology at the British Museum of Natural History. His specialty was beetles in the family Cerambycidae. He originally classified the PHB as Cyllene Caryae and it was later changed to it's current scientific name.

Sunday, March 1, 2015

Red Velvet Mite

Red Velvet Mites in the family Trombidiidae include more than a 1,000 species Worldwide. They are classified as arachnids, but differ from spiders in many ways. Spiders possess 6 or 8 eyes, mites only have 2. Spiders have two body segments, whereas mites have only one. Mites also have a unique leg arrangement. There are two legs located in four separate sections on the underside of their body. There are many other differences which are too technical for me, but suffice it to say, while related, they are like distant cousins on the spider family tree.

They are sometimes called rain bugs as they are active after heavy rains especially in the early spring or fall. The one pictured here was found after a spring rain while mushroom hunting. It was actively hunting for prey on a rotting log. I knew it was a velvet mite, but had no idea its identity beyond that. It is next to impossible to differentiate one species from another without a microscope with exception to a few Palearctic species like the giant red velvet mite (Trombidium grandissimum). This particular red velvet mite is found in India, and may reach lengths up to 1/2 inch. This species is a true giant in the mite world where most species are nearly microscopic in size. They get their common name of red velvet mite from the fine red hairs all over their body which resembles velvet and gives them the ability to sense their surroundings. In addition to using those fine body hairs, they also sense their environment through vibrations and pheromone responses. Their front legs aid in guiding them through the habitats where they live by acting as a sensory organ. Having only 2 eyes gives them a serious disadvantage in the eyesight department, so instead they rely on delicate vibrations and pheromones that cue them in on food and mates. The bright red color warns potential predators that they taste bad and therefore they have few enemies with exception to their own kind which may cannibalize them. The 2nd stage nymphs have also been known to parasitize them.

Even though they taste terrible, it seems humans have found a use for them in medicine. Oils from some species, like the Giant Red Velvet Mite are used in traditional medicine to treat paralysis. In some cultures they are used as an aphrodisiac, earning them the name of "Indian Viagra." They are also used in a treatment to improve the immune system. Like any creature that finds itself useful to humans it can often be removed from the environment in such drastic numbers as to affect the overall balance of the ecosystem where they were found. Red Velvet Mites are an integral part of the ecosystem as a biological control agent feeding on harmful arthropods such as spider mites, spring cankerworm, cabbage moth, lace bug, and other arthropods that may damage crops. As nymphs they act as ecto-parasites and also control many harmful insects.

Mating between red velvet mites is an involved process which includes the male performing a bit of a dance to impress the female. He will deposit a spermatophore nearby on a small twig, piece of bark, or blade of grass. He then forms a chemical trail made of silk that he guide her across, essentially walking her to his "gift." If she is receptive to his advances she will position her body on top of the spermatophore and remain there until she has taken all his sperm into her body, becoming impregnated. If another male happens upon this scent trail he will follow it to the spermatophore and break it open, he will then leave his own spermatophore in place of his competitors. Essentially ensuring his genes are passed on without all the work of finding the female, dancing his 8 tiny legs off, and walking his female to his present. What a lazy little trickster!

The female will lay her eggs, from 60-100,000 depending upon species, in the soil, leaf litter or other organic matter. When the eggs hatch the newly born pre-nymphs stay very close to the area where they were born. After a few days they leave and take on the life of an ecto-parasite feeding on various arthropods, including grasshoppers, crickets, arachnids, aphids, etc. (pictured: mites feeding on Harvestman)

In most case their feeding does not kill the host, but in some cases their numbers are so large the host cannot survive. The next stage, called protonymphs   are calyptostatic and develop inside the cuticle of the larvae. They lie inactive like a pupa. After emerging from the cuticle of the host they now possess eight legs and are more active hunters, searching out prey, rather than attaching themselves to a host. They generally complete their lifecycle and become adults in the fall. It is common to see them after the first heavy rain in autumn. Any eggs that hatch in the late summer or early fall will not have time to complete their lifecycle to adulthood. Those individuals will overwinter and complete their lifecycle the next year or in some cases the following year.

These fuzzy little arachnids are common, yet rarely seen, brightly colored, yet harmless to humans, voracious predators, yet excellent biological pest control. When the spring rains return, head to the timber and search for these unique, fascinating, brightly colored arachnids as they hunt for food and mates among the forest floor. These tiny mites are a true treasure of the woodlands.