Beetles are generally divided into carabids and non-carabids depending on whether they have developed trochanters on their hind pair of legs or not. Carabids have developed trochanters that resemble beans. These trochanters help carabid beetles to walk and run much quicker than non-carabids. Thus, most beetles that reside on the ground or trees are carabids because they have more maneuverability than non-carabids.
Beetles are one of the most common insects in the world, and they inhabit a wide variety of habitats. They occur both on land and under water, and their sizes can range from as small as 0.25mm to 20cm.
Beetles are one of the strongest group of animals on Earth. Even though they are small, they can lift objects many times heavier than themselves. For instance, the Hercules Beetles (Dynastes hercules) can lift more than 850 times their body weight. If an average adult weighing about 165 pounds (approx 75kg) was as strong as the Hercules Beetles, he could lift an object weighing over 60 metric tons! Incredible!
The order Coleoptera is easily my favorite one of the arthropod orders. It was a pair of stag beetles that got me seriously interested in insects, after all. Asian stag beetles are quite awesome in their appearance. Unlike most of the stag beetle species in North America, the male Asian stag beetles have much more developed mandibles. This gives them a more fearsome look and overall, makes them look much cooler, in my opinion.
The following are the Coleopteras that the GAS and I have found so far.
Cerambycidae - Megacyllene - Megacyllene robiniae (Locust Borer): Don't worry, they aren't bees! At a fleeting glance, you could easily mistake them for bees because of their yellow and black striped bodies. However, if you look closely, you will definitely see that it's a beetle. You can recognize these beetles by the ‘W’ marks across their elytra (wing covers). They have red-orange legs and antennae that are more than half their body length.
These beetles are considered to be pests in most cases
because the larvae live in and damage locust trees. The adult beetles lay their
eggs in the fall, which spend the winter under a shallow bark. When the larvae
hatch in the spring, they bore down into the wood and create ‘galleries’ that
weaken the wood’s structure.
For more detailed pictures that I took with a microscope camera, click here.
Coccinellidae - Harmonia - Harmonia axyridis (Halloween Ladybug): This species was the first beetle that I identified because there are so many of these in the main building of our school. I ended up writing a short article on it so that at least some interested people would find out why these beetles like our buildings so much. The details are in Article 2 that I wrote, so I will just summarize the important facts about these little jewels.
Also known as Asian Multi-colored ladybugs or Halloween ladybugs, they were introduced to America from Asia, as their name indicates. They are also called Halloween ladybugs because they appear in New Englands around Halloween. They tend to creep into households near the end of fall to stay warm. They are harmless to humans, so don't be afraid to study them up close! You can tell these apart from other ladybugs by the 'M' mark on the top of their pronotum.
For more detailed pictures that I took with a microscope camera, click here.
Lampyridae - Ellychnia - Ellychnia corrusca (Diurnal firefly): Fireflies are beetles that belong to the Lampyridae family. They are called fireflies or lightening bugs because of their ability to emit light from the end of their abdomens. The light that they produce are referred to as “cold light” because it doesn’t contain UV or IR rays and thus do not have heat.
Fireflies don’t really look like typical beetles at first because they do not have hard, rigid elytra (wing cover) that many other beetles have. The easiest way to distinguish a firefly from many other insects is of course, the lights. Most species of fireflies emit light, although some diurnal species don’t. This light that fascinates many people come from the reaction of the enzyme luciferase on the chemical luciferin in the presence of Mg+ ions, oxygen, and ATP. The reason that fireflies consume so much energy to emit light is to successfully mate with a member of their species. Usually the males fly around emitting light while the females stay on the ground and take their pick.
The light that fireflies emit is very efficient. Compared to typical light bulbs that convert less than 20% of energy into light, fireflies convert about 90% of energy into light. It’s a pretty cheap method of getting light, and in fact, a dedicated, but impoverished Korean scholar hundreds of years ago studied at night by the light of fireflies in a paper lantern.
For more detailed pictures that I took with a microscope camera, click here.
Scarabaeidae - Popillia - Popillia japonica (Japanese beetle):Popillia japonica, also known as Japanese beetle, is a scarab beetle about 15mm long and 9mm wide. Its elytra, or the hard, sheath-like wing cover, is copper colored whereas its thorax and head is metallic green. Scarab beetles can be distinguished from other families of Coleopteras by their clubbed antennae. Although there are other beetles with clubbed antennae, scrab beetles’ antennae have a distinct look to them, which you can see in the detailed pictures if you look closely. Simply put, their antennae end in a three-branched club. There are other beetles with clubbed antennae, but scarab beetles are the only ones with such branched clubs.
Like all beetles, P japonica start off as larvae and go through the pupa phase to become adult beetles. They usually live for a year, but in their native country, they can often live up to two years.
In the United States, P japonica are serious pests because they consume and skeletonize (leave only the transport veins in leaves) various plants, including grapes and rose bushes and also because they lack natural predators that are present in Japan but not in the States. Studies are currently being done to try to minimize their damage to plants.
