Comparative Studies of Reproductive Diapause in North American Populations of Three Hippodamia Species (Coleoptera: Coccinellidae)

Adult Hippodamia parenthesis were collected from McLean County, Illinois (40.34°N, 88.77°W), Johnson County, Iowa (41.67°N, 91.52°N), Onondaga County, New York (43.03°N, 76.00°W) and Jefferson County, New York (43.98°N, 75.91°W) (Supplemental Figure 1). Eggs were collected daily from 4 to 6 females in each population and placed in L:D 16:8, 14:10, 12:12,10:14, at 22°C ± 1.0°C. F1 offspring were individually reared in glass vials at each photoperiod on pea aphids and Ephestia kuehniella eggs to examine the effects of photoperiod on development (Data set: H. parenthesis Development times at LD).

Comparisons of the developmental responses of H. parenthesis, H. variegata and H. convergens were made: [data for H. variegata from Obrycki 2018; (Data set: H. parenthesis and H. convergens from three counties in Iowa)]

Pairs of F1 Hippodamia parenthesis adults from each population were maintained at the same larval photoperiod. Pairs were fed and maintained at each photoperiod for 120 days. The date of first oviposition was recorded for each female. (Data set: Four populations of H. parenthesis response to LD (McLean Cty, IL, Johnson Cty, IA, Jefferson Cty, NY, Onondaga Cty, NY)

Comparisons of the female responses to photoperiod between species collected from the same location or at similar latitudes included:
H. parenthesis and H. variegata from McLean County, IL, (Data set: H. parenthesis and H. variegata from McLean County, IL)
H. parenthesis and H. variegata from Jefferson County, NY, (Data set: H. parenthesis and H. variegata from Jefferson County, NY)
H. parenthesis and H. convergens from Boone, Polk, and Johnson Counties in IA. (Data set: H. parenthesis and H. convergens from three counties in Iowa)

Data for H. variegata are from Obrycki (2018); data for H. convergens are from Obrycki et al. (2018).