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Saturday, August 28, 2021

Hoppin' Orthoptera

Grasshopper nymphs are often mini versions of the adults

Take a walk through a meadow on a late summer or early fall day, and you’ll no doubt encounter members of the insect order Orthoptera: grasshoppers, crickets, and katydids.  While their Greek name translates to ‘straight wings’, these insects are better known for their jumping ability and powerful hind legs that can propel them to 20 times their body length. 

Abundant, large, colorful, and often noisy, orthopterans are unlike other insects in that they undergo an incomplete or gradual metamorphosis.  Their simple lifecycle consists of an egg, nymph, and adult, where the nymphs look similar to adults, but lack completely developed wings.  Eggs typically hatch in the spring, nymphs develop through the summer, adults mate and reproduce in late summer and fall, with winter passing in the egg stage.  They have three basic body parts: the head, which contains sensory parts such as antennae, eyes, and mouthparts; the thorax, which contains the legs and wings required for movement; and the abdomen, which bears the digestive and reproductive organs.

The use of sound is crucial in courtship, with each species having its own distinct song.  Males attract mates through stridulation, or producing sounds by rubbing the upper and lower wings or the hind leg and wing together creating a vibration that is species-specific.  The auditory organs for orthopterans are not located on their heads, however, but on the abdomen for grasshoppers and the front legs of crickets and katydids.

Differential Grasshopper

Common throughout Texas is the Differential Grasshopper (Melanoplus differentialis), which is brown to olive-green and yellow and up to 1.8 inches long, with black herringbone markings on its legs.  It feeds on both grasses and broadleaf plants, although it prefers the latter, and is often found in areas of lush vegetation. Both nymphs and adults tend to aggregate together, and the adults are found from July to October.

Obscure Bird Grasshopper

Also found thoughout Texas is the Obscure Bird Grasshopper (Schistocerca obscura).  This large grasshopper, to 2.5 inches long, has olive-green forewings and typically a pale yellow-green dorsal stripe from the front of the head to the wing tips. While females can lack this stripe, both sexes have blackish-purple tibia with yellow, black-tipped spines.  This species prefers fields and open woodlands, and can sometimes feed on flowers and shrubs.

Green-striped Grasshopper

The Green-striped Grasshopper (Chortophaga viridifasciata) is found everywhere in Texas except for the southernmost portion of the Trans-Pecos.  Up to 1.5 inches long, it has both a green form (usually females) and a brown form (usually males). Between forms, the main difference is the coloring of the head, thorax, and outer face of the hind femora, with the abdomen always being reddish-brown. This grasshopper prefers wet areas with short grasses on which to feed.    

Narrow-winged Tree Cricket

More often heard than seen, Tree crickets (Oecanthus sp.) are whitish to light green, with long antennae and slender bodies.  In late summer from dusk into the evening hours, the males begin to chirp, with the rate of the chirp correlating to the outside temperature.  If you count how many chirps you hear in 15 seconds and add that to 40, you’ll come surprisingly close to the actual air temperature in degrees Fahrenheit.  

Field Cricket

Field crickets (Gryllus sp.) are dark brown to black, about 1 inch long, live in cool, dark areas, and normally emit high-pitched, continuous calls.  Those that live in caves are dark brown, have well-developed hind legs, and exhibit a hunchbacked appearance.

Fork-tailed Bush Katydid

The antennae of katydids are hair-like and at least as long as the body, superbly represented by the Fork-tailed Bush Katydid (Scudderia furcata).  This all-green katydid is often found in weedy fields, thickets, forest edges, and along roadsides. Up to 2.2 inches long, the first generation matures in late spring and the second in early fall.  Interestingly, the overall size of the adults varies and is directly related to how fast they must mature in order to fully use the growing season to produce the maximum number of generations.

Often, what you can’t identify by sight during the day becomes clear when it sings, calls, buzzes, or chirps at night.  Immerse yourself in the nighttime soundscape, and hear your way to discovery!