Alstad, D.N., Edmunds, G.F., & Johnson, S.C. 1980 Host adaptation, sex ratio, and flight activity in male black pineleaf scale.. Annals of the Entomological Society of America 73: 665-667.

Notes: Abstract: Field studies of Nuculaspis californica revealed a biased sex ratio which varied from tree to tree; male frequency correlated with insect density and adaptation to a single individual ponderosa pine, Pinus ponderosa; sticky-trap capture data showed a diurnal pattern of male flight activity. Keywords: males.