Jh. Lee et Nc. Elliott, COMPARISON OF DEVELOPMENTAL RESPONSES TO TEMPERATURE IN APHELINUS-ASYCHIS (WALKER) FROM 2 DIFFERENT GEOGRAPHIC REGIONS, The Southwestern entomologist, 23(1), 1998, pp. 77-82
Aphelinus asychis (Walker) was imported to the United States for class
ical biological control of the Russian wheat aphid, Diuraphis noxia (M
ordvilko). Temperature effects on development of A. asychis colonies f
rom two geographic regions (hereafter referred to as strains) were mea
sured at four different temperatures (14, 18, 22, and 26 degrees C) us
ing the Russian wheat aphid as the host species. Developmental thresho
lds for development from egg to the adult stage were 8.2 and 9.3 degre
es C, respectively, for strains collected near Pingluo, China, and Set
te, Morocco. Corresponding degree-day requirements were 229 and 198 fo
r the two strains. The Chinese strain required less time than the Moro
ccan strain to develop from egg to mummy, while the Moroccan strain re
quired less time to develop from mummy to adult. Differences in charac
teristics of stage-specific development in relation to temperature are
discussed in relation to the climate of the place of origin of the st
rains.