Variation in Opsius stactogalus (Homoptera: Cicadellidae) egg density among Tamarix ramosissima (Tamaricaceae) trees

Tamarix ramosissima Ledebour trees at three localities in southern Nevada were sampled for overwintering Opsius stactogalus Fieber eggs. Localities contained trees next to abandoned pasture, a perennial river, or treated wastewater. Eggs were sampled once in each of two years on stems cut from two branches on each of eight dormant trees at each locality. Egg densities (eggs per stem surface area) varied among localities and among trees within localities but not between branches within trees. Variance in egg density among localities was 23-times greater than among trees within localities, suggesting leathopper abundance was influenced more by environmental factors (probably soil moisture and nitrogen concentration) than by genetic differences among trees. Correlation of egg densities on Tamarix trees between years indicates the dispersion of O. stactogalus among trees was continual, potentially influencing oviposition by the leafhopper's insect parasites.