Developmental biology of an exotic scale, Acutaspis albopicta (Hemiptera: Diaspididae)

Acutaspis albopicta (Cockerell) is one of seven exotic scale species detected on shipments of'Hass' avocados entering California from Mexico. Here, we present the results of experiments to elucidate basic life history parameters of this species. The scale only reproduces sexually with unmated females producing no offspring. Unmated females survived up to 14 wk after settling on host fruits, whereas males survived for up to 62 h, with the majority dying within 46 h after emergence. Females laid a mean of 52.0 +/- 2.8 eggs (range, 5-171 eggs). Lower humidity (50%) was detrimental to the survival of male scales compared with high humidity (75%), especially during the pupal stage. The optimal temperature for development of both sexes was 25 degrees C. At this temperature, females developed from first instars to adults in approximately 28 d, whereas males emerged from their pupal cases after approximately 37 d. The adjusted lower developmental thresholds for females and males were 13.2 and 13.4 degrees C, respectively. The upper developmental threshold for both females and males was approximately 32 degrees C. Total development from first instar to adult female was 329 degree days and to emerged male, 433 degree days.