Wednesday, February 18, 2009

Tettigoniidae

The following are two species of Katydid - the medium-sized one I thought was an instar of the larger one, but apparently they are different species. Each is about 3 inches long, wingspan about 4 or 5 inches. The largest and smallest specimens were caught in the San Diego area, and the medium specimen was caught in La Verne.



Orthoptera; Tettigoniidae; Phaneropterinae; Microcentrum rhombifolium
Common Name: Greater Angle-Wing Katydid



Orthoptera; Tettigoniidae; Phaneropterinae; Scudderia mexicana
Common Name: Mexican Bush Katydid



Orthoptera; Tettigoniidae; Phaneropterinae;
Unknown nymph - possibly Scudderia mexicana, Microcentrum retinerve (Lesser Angle-Wing Katydid), or Microcentrum rhombifolium.

Katydids communicate through song, and the subfamily Phaneropterinae is commonly called "False Katydids." They can vary in color from brown, to pink, to green, and often mimic leaves. The Greater Angle-Wing Katydid is differentiated from the Lesser Angle-Wing Katydid by a small tooth on the dorsal, frontal edge of the thorax - that part of the Lesser Angle-Wing Katydid is smooth. The Greater Angle-Wing Katydid is common in Southern California. They eat plant material and develop through several molts called instars, the final instar being winged. As a mating ritual, the male brings the female a nuptial meal, a spermatophylax, which is a gelatinous blob of carbohydrates, protein, and water. The male mates with the female while she is consuming the spermatophylax. As a result, the larger the meal, the longer it takes the female to consume it, and the longer time the male has to inseminate her, thereby producing more offspring.

As for the Mexican Bush Katydid, it is a member of the Scudderia genus, or Bush Katydids. Bush Katydids do not fly often, but glide from bush to bush and their forewing is noticeably shorter than the hind wing, with an elongate, narrow appearance relative to other genera. The species are mostly differentiated through male genitalia, and I did not key this specimen to species - I merely suspect it is Scudderia mexicana. The nymph may be a member of Scudderia because its femur is smooth, compared to Microcentrum which has spines on the femur.

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