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Biology of the tenlined June beetle (Coleoptera: Scarabaeidae)

Van Steenwyk, R.A., Rough, D.
Journal of economic entomology 1989 v.82 no.6 pp. 1738-1742
soil fauna, Polyphylla decemlineata, oviposition, seasonal variation, sexual reproduction, insect traps, mating behavior, Prunus dulcis, California
The biology of the tenlined June beetle, Polyphylla decemlineata (Say), was studied over a 3-yr period in an almond, Prunus amygdalus Batsch, orchard in Manteca, Calif. The beetle has one generation every two years and passes through three instars. The beetle overwinters as a first instar during the first winter and as a third instar during the second winter. The majority of larvae are found 0.1-0.35 m deep in the soil. The percentage of first instars decreased with increasing soil depth from 77% of all larvae found at 0.05 m to 13% at 0.6 m. The percentage of third instars increased with increasing soil depth from 13% of all larvae found at 0.05 m to 58% at 0.6 m. Adult emergence begins in mid-June and continues through mid-October with peak emergence in early August. Adult male flight is crepuscular. Mating occurs at the female emergence site at sunset. Females laid an average of 11.6 eggs.