Observations on the Bionomics of Euborellia annulipes (Dermaptera: Labiduridae)1

Abstract

The ring-legged earwing, Euborellia annulipes (Lucas), was studied in the laboratory, at 68°–84°F and with a daily light period of about 10 hr. Plastic refrigerator boxes and Pyrex crystallization dishes, containing a 3:1 mixture of moist soil and coarse sand, were used for rearing. Powdered dog meal, supplemented occasionally with freshly killed insects and sowbugs, served as food for nymphs and adults. Details considered include distribution in the United States, economic importance, habits, reflex immobilization, autotomy, cleaning, function of the forceps, parasites and predators, and control, as well as mating behavior, nidification, oviposition, maternal care, and the several life-history stages. Oviposition began 1–23 days after mating, occurred throughout the year (usually at night), and averaged 52.7 eggs/clutch. Some females laid 4 clutches, on successive days. Minimum incubation periods in different clutches were 6–17 days, and hatching continued 2–4 days. Usually there were 5 nymphal stadia with average durations as follows: first, 10 days; second, 9.5 days; third, 11.5 days; fourth, 14.1 days; and fifth, 18.3 days. Four out of 33 individuals had a sixth nymphal stadium which averaged 20.2 days. Characters useful for distinguishing the nymphal instars include body length, width of head, length of prosternum, length and width of pronotum, total number of antennal segments, and number of segments in the “middle region” of the antennae, though considerable overlap between instars was found in some of these.