Late summer and early fall is the time spiders and daddy-long-legs become active, at least more noticeable around the house and yard. Daddy-longlegs are not spiders, but are placed in their own Order, called Phalangidae (from the Greek Phalangida, meaning a finger or toe). These long-legged cousins to spiders are common throughout the country. They are characterized by their long legs and oval body, and perhaps by their slow, methodical walking behavior. Most species of daddy-long-legs feed on plant juices, some feed on dead insects, and some are predators of living insects (quite a range in diet!). They are not a threat to man, as none of them will bite. There are numerous species in Virginia, and they are found from spring to fall. The eggs are laid beneath rocks or in some other protected place; they over-winter in the egg stage. I know of nothing that would be effective in controlling them, short of trying to spray all of them with an aerosol or compressed-air sprayer. Why bother, they are not a threat to anything.
A question that is often asked is whether there are tarantulas in eastern U.S.-because someone has seen a very large spider and considered that it must be a tarantula. There are large species with the dense covering of setae over the legs and body--that most of us think of as tarantulas (the kind they use in the movies!). However, there are some very large species of wolf spiders in this state that can be mistaken for a tarantula (especially if you have never seen a real tarantula). The Carolina wolf spider is a very large species that is often found living near small streams. This spider can be found around and inside houses at times. Like other wolf spiders, it does not make a web but moves around to hunt for its prey. They are no threat to man, but you can get a nasty bite if you handle one (can't imagine anyone actually doing that).
The Allegheny mound ant builds the largest anthills of any of the North American ants. This is not a common ant species in eastern U.S., but it can be found in most areas of this region, except perhaps the coastal regions. The mounds are small to large cones, 12 to 36 inches high and several feet in diameter. The vegetation around the mound is usually cleared away, and the surface of the mound may be littered with dead plants. This species, Formica exectoides, is red and black, and a rather large ant. The colonies can be very large, with more than a thousand queens and 200,000 workers. Unfortunately, these ants are just a little aggressive! If you stand idly near they nest, it is not uncommon for them to attack, and they can deliver a nasty bite. Control is best achieved by drenching the nest thoroughly with a liquid insecticide.
Toward the end of summer cicada killers become most active. Their prey are the annual or "dog day" cicadas (so named because they emerge and sing during the time the dog star Sirius rises and sets with the sun. These are very large wasps, and large they must be to handle their prey--annual cicadas, which are large insects. The wasp typically grabs the cicada from the branches of trees where it is sitting and singing (if a male), stings the cicada (immobilizes it), then carries it back to the gallery it has constructed in the soil. The wasp must take the cicada from a tree branch, since it needs the height to take off and fly with it. If the cicada is dropped the wasp will have to carry it up the tree trunk to find a location from which it can take off! This dropping and climbing is not uncommon for the cicada killer--a cicada is a difficult thing to carry and hold on to! Once at the nest site the cicada is tugged below ground and an egg is laid on the cicada body. The immature wasp that hatches from the egg penetrates the cicada and feeds on the cicada body. When full grown it spins a cocoon and pupates. The adult cicada will not emerge until the following summer--then start hunting cicadas. While the cicada killer is a big and frightening wasp, it rarely poses a threat to man. It is not very aggressive toward humans, and it rarely stings. Sometimes there can be several cicada killer nests in one location. They seem to prefer soil that is easily worked and well drained.
These insects have piercing mouth-parts and can deliver a severe bite to the unsuspecting person that handles them. They are often found associate with vegetable and flower gardens, where they can find other insects to attack and feed on during their development and in the adult stage. These insects grow slowly during the summer, and do not become adults until fall (but they can bite you as immatures!). They don't seek to bite people, but will if they are picked up or brushed against. The wheel bug has a characteristic shape. The "wheel" (what looks like part of a wheel with spokes) is located on the region just behind the head. When they are encountered just leave them alone--let them continue to feed on the insects found in the garden! They may do some good.
Homeowners/pet owners often encounter horsehair worms in their pet's food or water dish this time of year. Usually causes a panic--they figure their cat or dog got some sort of parasite! Well, the truth is that these worms are parasites of crickets and grasshoppers--not pets. They complete their development inside the cricket during the late summer and exit the host. The exit usually occurs when the parasitized insect lands in a water dish or a small pool of water. Certainly, there is no need for control of these critters.