Aldrich Entomology Club

 Lethocerus americanus:

Lethocerus americanus is a giant water bug in the order Hemiptera.  It is native to North America and is one of our largest insects.

• They are 1-2 inches in length, brown or tan colored, with an oval, flattened body.
• They live in ponds, marshes, at the edges of lakes, and slow moving streams.
• They feed on small crustaceans, tadpoles, snails, other insects, and even small fish.

AKA: toe biters.  They can inflict one of the most painful bites of any insect!

AKA: electric light bug. They are attracted to electric lights when they fly at night.

They are fierce predators that stalk their prey.  They use their front forelimbs to capture and hold onto prey.  Then, using a retractable proboscis, they can inject prey with digestive toxins before consuming them.  Adults breathe using two short tubes at the tip of their abdomen. These tubes help exchange air from the atmosphere into a bubble trapped under their wings.  Adults lay eggs on vegetation located at the water’s edge and the eggs are often guarded by an adult.

 Lethocerus americanus can make good aquarium pets.  However, the aquarium lid must be completely closed or the insect could escape!

Two other interesting giant water bugs!

In the giant water bug species Abedus indentatus, females lay their eggs on the backs of males for protection!

And in Thailand, Lethocerus indicus is a popular dish when deep fried!

- Jessica Rendon

Pterostichus melanarius (Coleoptera: Carabidae)

Exotic… but not that kind of exotic.

When most of us hear about an exotic insect our minds quickly go to images of large brightly colored insects indigenous to far off tropical places; not a dull, monochromatic, mostly flightless beetle. However, P. melanarius is an exotic introduction. Originally from Europe, P. melanarius is quickly spreading on both the Atlantic and Pacific coasts. Other insects may beat P. melanarius in a beauty contest; but what this flightless, ordinary, lack luster insect lacks in aesthetics, it makes up for with stealth, brute strength and a tremendous appetite.

An eating machine.

A relatively large beetle ranging in size from 12-17mm P. melanarius are said to feed on anything they can subdue including; caterpillars, fly larvae and pupae, earwigs, aphids, crickets, lacewing eggs and larvae, other immature beetles, meal worms, earthworms, slugs, snails, young salamanders, and carrion.  Adults are voracious feeders and have even been recorded killing prey when satiate.

Although P. melanarius is largely carnivorous, it won’t shy away from a vegetarian meal in a pinch. Tree seeds, grass tissue, and strawberries are also on the menu.

Squish or Spare?

If/when you encounter this bug, definitely spare it. Because of their voracious appetites and feeding practices, P. melanarius are helpful to people and play an important role in pest suppression.

Where can I find it?

This beetle is common in a variety of habitats and may be easily found by turning over stones, logs, or pieces of wood. Be careful, P. melanarius may produce a foul smelling spray from specialized glands in their rear (pygidial glands) when disturbed or alarmed, but are otherwise harmless.

- Kristin Daku

This fly belongs to the Tephritidae “Fruit Fly” family.  Unlike the majority of its family members, it does not feed on the fruit or seeds of its host plant.  Instead, U. cardui is known as the thistle stem gall fly.  It spends most of its life in larval form feeding on nutritive tissue inside Canada thistle stems.  The larvae have the ability to “trick” the host plant using chemical signals, to produce an ellipsoid shaped structure on the stem called a gall. It will grow into an adult inside this protective and nutritive housing.  Once a larva matures to an adult fly, it can shimmy its way out of the gall where it will shrink its head, pump up its abdomen, and spread its wings!  The adult fly will compensate for any nutrition deficit occurred as a larva by feeding on the syrupy liquid produced by flowers.

The unique wing pattern found in this family can be used by the male for courtship of the female on the host plant.  The banded “W” pattern of this fly may imitate spider legs as it moves the wings in a pattern like that of a jumping spider.   This would be very useful in thistle patches, which are filled with spiders, for scaring away predators.

U. cardui is important to humans for its potential to biologically control its host plant, Canada thistle (Cirsium arvense).  This thistle (despite its name) is not native to North America and is considered by many to be a problematic weed.  The galls the larvae form can absorb much of the plants needed nutrients resulting in stunted growth and reduced ability of the plant to compete with other plants.  Any additional tool in the fight to control weeds is considered significant.  I consider this fly significant!

- Joel Price