four-spotted tree cricket

not listed

NNR - Unranked

not listed

Four-spotted tree cricket is a common singing insect. It occurs in the United States, southern Canada, and northern Mexico. In the U.S., it is the only Oecanthus species that is found in all 48 of the contiguous states. It is found in a variety of habitats, including gardens, roadsides, and borders of agricultural fields.

Though called a tree cricket, four-spotted tree cricket is usually found on grasses, shrubs, and weeds less than three feet above the ground, and often less than one foot above the ground. It is not found in trees. The genus name Oecanthus is Greek from “to inhabit” and “flower”.

Adult four-spotted tree crickets are active from August to November. They are omnivorous. They feed mostly on plant matter, including leaves, fruits, and flowers, but they also feed on smaller insects and other invertebrates, and on insect eggs.

Adults are 7⁄16″ to 11⁄16″ (11.5 to 18 mm) in length, which is small and slender for an orthopteran but medium-sized and robust for an Oecanthus.

The head is pale yellowish green. The compound eyes are yellowish. There are no small simple eyes (ocelli). The antennae are pale brown, thread-like, and very long, often two-and-a-half times as long as the body.

There are 18 Oecanthus species in North America north of Mexico. They are very similar in appearance and are usually identified by the markings on the first and second antennal segments. This character is difficult to observe in the field, or even from most photographs, but it is very useful in determining the species. On four-spotted tree cricket, the first and second segments are pale green and there are two black marks on the underside of each. This is the feature that gives the species its common name. On the first segment, the inner mark is about two-thirds the length of the segment. The upper end of the mark is bent outward, toward but not touching the outer mark. The outer mark is short and almost round. On the second segment, the marks are oblong and parallel. The inner mark is about twice as long as the outer mark.

The body is pale yellowish green.

The exoskeletal plate covering the thorax (pronotum) is longer than wide. It is slightly narrower in the front than in the rear. The corners of the lower lobes are rounded.

On the underside of the abdomen is entirely pale, with no black spots. On the female, the needle-like egg-laying tube at the end of the abdomen is straight.

The leathery front wings (tegmina) on the male are translucent, flat, and rigid. They are much wider than the abdomen. The tips are broadly rounded. The veins are greenish yellow. On the female, the tegmina are narrower and membranous. They are held tightly wrapped about the body.

On the female, the hindwings are as long or slightly longer than the tegmina. On the male they are always slightly longer than the tegmina.

The legs are very slender. They are dull greenish yellow. The third segment (femur) of all legs is unarmed. The fourth segment (tibia) on the hind legs is armed with two rows of three to six long spines with numerous minute teeth between the spines. There are also three pairs of strong spines near the tip of the hind tibia. The last part of each leg (tarsus), corresponding to the foot, has three segments. The basal segment is longer than the other two combined. The tarsi are often partly tinged with black.

The song is a shrill, continuous trill, whi-r-r-r-r, repeated several times with varying lengths, the entire song lasting several minutes. The pulse rate of the song varies with the air temperature.

At 65° F (20° C) there are about 28 pulses per second.

At 75° F (25° C) there are about 38 pulses per second.

A variety of habitats, including gardens, roadsides, and borders of agricultural fields

One generation per year: August to November (adults)

Males sing both day and night.

Mating begins in August. Eggs are laid from September through November. The eggs overwinter and hatch in June the following year. The nymphs undergo paurometabolous development (gradual metamorphosis) and look like small adults. They take 13 months to mature into adults.

Same as adults

Mostly plant leaves, fruits, and flowers, but also smaller insects and other invertebrates, and insect eggs,

Sources

27, 29, 30, 82, 83.

Walker TJ. 1963. The taxonomy and calling songs of United States tree crickets (Orthoptera: Gryllidae: Oecanthinae). II. The nigricornis group of the genus Oecanthus.  Ann. Entomol. Soc. Am. 56: 772-789.

Common and widespread

Four-spotted tree cricket is very similar to black-horned tree cricket (Oecanthus nigricornis). It was once treated by some entomologists as the subspecies Oecanthus nigricornis quadripunctatus, and by others as a mere color variation of Oecanthus nigricornis.