干旱区生态环境知识资源中心

Daily rainfall at climatological-data weather stations near collection localities of adult Oliarces clara Banks was examined to determine if spring emergences occurred in years following rainfall regimes favoring spring vegetative growth by desert shrubs including Larrea tridentata (De Candolle) Coville, the insect’s suspected larval host. Thirteen of 18 emergences examined were preceded by individual rains with total rainfall exceeding thresholds (25 mm during autumn [21 September-10 December] or 50 mm during winter-early spring [11 December-10 April]) stimulating plant development, and this proportion was higher than expected compared with the historical occurrence of similar high-rainfall events. The remaining five emergences were preceded by individual rains associated with plant growth during spring being variable or absent. Emergence by O. clara adults coincident with physiological development by desert shrubs may directly or indirectly provide soil-inhabiting larval offspring with a food supply of required abundance and quality.