Curious Oviposition Behavior in Phyllium westwoodii (Phasmatodea: Phylliidae): Preliminary Observations.
Bottom Line: We report that in a leaf insect, Phyllium westwoodii Wood-Mason (Phasmatodea: Phylliidae), two differing apertures can be used for oviposition, the color of eggs being affected by which aperture is used.Eggs which are forcibly propelled from the internal space within the valvulae of the abdomen are brown, whereas white eggs emerge slowly from the opening between the eighth sternite and the valvulae, and are deposited close to the ventral surface of the female.This unusual oviposition system does not appear to have been previously reported in phasmatids or in other insects.
Affiliation: Shirayuri Gakuen Junior High School, 2-4-1 Kudanshita, Chiyoda-ku, Tokyo 102-0073, Japan.Show MeSH
Mentions: Among the reared females of P. westwoodii, 14 d after commencing the laying of brown eggs, we allowed one of the females to copulate with the male. Two days after this, the female produced white eggs from the intersegmental region between the eighth sternite (subgenital plate) and the anterior valvulae (Fig. 2B). These white eggs were similar in size and texture to the brown eggs. However, the white eggs were not flung away using the valvulae but instead emerged slowly from the opening between the eighth sternite and the anterior valvulae. After a short time, they were laid close to and almost underneath the female (3.5 ± 1.6 cm, mean ± SD, n = 10). About 10 min after oviposition, the white eggs darkened to a pale brown with an orange tint and then remained unchanged in color after that point. They were clearly different form the dark-brown eggs laid through the valvulae (Fig. 3). This female laid 18 white eggs over 21 d and simultaneously continued to lay 45 brown eggs from within the valvulae during this period (Fig. 4).Fig. 3.
Affiliation: Shirayuri Gakuen Junior High School, 2-4-1 Kudanshita, Chiyoda-ku, Tokyo 102-0073, Japan.