Rhagoletis tabellaria (Fitch, 1855)

Yee, W. L., Forbes, A. A. & Feder, J. L., 2020, Eclosion and adult longevity traits of Rhagoletis tabellaria (Diptera: Tephritidae) and Utetes tabellariae (Hymenoptera: Braconidae) in the laboratory, The Canadian Entomologist 152 (2), pp. 145-158 : 149-151

Eclosion of Rhagoletis tabellaria and Utetes tabellariae , 150-day and 120-day chill

When R. tabellaria puparia were chilled at 2.7 °C for 150 days and held at 24.3 °C ( Fig. 1B ), eclosion occurred at 20–30 days (11-day span) for females and 18–31 days (14-day span) for males, peaking at 23 days for both sexes. Both sexes eclosed significantly earlier than female and male U. tabellariae (Χ 2 = 28.67; df = 3; P <0.0001) ( Table 1), which eclosed at 30–43 days (14-day span; sexes combined), with a peak at 30 days. Male wasps eclosed approximately five days earlier than females, although the difference was not significant ( Table 1).

When R. tabellaria puparia were chilled at 2.7 °C for 120 days and held at 24.3 °C ( Fig. 1C ), eclosion occurred at 19–32 days (14-day span) for females and at 20–29 days (10-day span) for males, peaking at 25 days for males and 26 days for females. Male flies eclosed earlier than females and both sexes eclosed significantly earlier than female and male U. tabellariae (F = 13.97; df = 3, 56; P <0.0001) ( Table 1, Fig. 1C ), which eclosed at 30–45 days (16-day span), with peaks at 30–45 days (due to low sample size). Male wasps eclosed approximately five days earlier than females, but the difference was not significant ( Table 1). However, when 195-day, 150-day, and 120-day chill treatments were each considered an observation and analysed using a paired t -test, male wasps eclosed significantly earlier (34.3 ± 0.6) than female wasps (39.5 ± 0.6) (t = 101.29; df = 2; P <0.0001).

To test for differences between the 150-day and 120-day chill treatments, data for female and male R. tabellaria (P> 0.05) were combined. Flies eclosed on average 1.4 days earlier in the 150-day than 120-day chill treatment, with means of 23.3 ± 0.3 versus 24.7 ± 0.4 days, respectively (rank, 150 days: 57.3; 120 days: 75.4) (Χ 2 = 7.47; df = 1; P = 0.0063). In addition, 74.8% of 150-day chill puparia (n = 103) produced flies, whereas only 51.0% of 120-day chill puparia (n = 100) did (Χ 2 = 12.29; df = 1; P = 0.0005).

There was no significant difference in mean days to eclosion between U. tabellariae experiencing 150-day versus 120-day chill treatments (sexes combined) (F = 2.86; df = 1, 18; P = 0.1082), although numerically wasps eclosed earlier in the 150-day chill treatment ( Table 1; Fig. 1B–C ). In contrast to fly eclosion rates, there was no significant difference in wasp eclosion rates per fly puparium (per cent of fly puparia producing U. tabellariae ) in the 150-day (10.7%) versus 120-day chill treatment (9.0%) (P> 0.05).

Days puparia at

4.8 °C or 2.7 °C °C for eclosion

R. tabellaria

Females Males

U. tabellariae

Females Males 195 23.2 22.6 ± 0.2 (195.7b) 21.4 ± 0.3 (154.9c) 39.6 ± 0.9 (379.6a) 34.3 ± 0.9 (361.1a) n 186 165 13 27 150 24.3 23.6 ± 0.4 (41.6b) 23.1 ± 0.5 (36.5b) 38.5 ± 2.9 (84.6a) 33.3 ± 1.2 (80.9a) n 39 38 4 7 120 24.3 25.5 ± 0.7b 23.8 ± 0.4c 40.5 ± 1.6a 35.3 ± 2.7a n 26 25 6 3 0 20–22 No fly eclosion No fly eclosion 28 ———— n 0 0 2 (plus 1 escaped) ————

Note: Values within rows (means,or ranks inside parentheses when data not normal) followed by the same letter are not significantly different (P> 0.05).

n, number of individual R. tabellaria or U. tabellariae that eclosed. Rhagoletis tabellaria puparia from Cornus sericea berries collected at three sites: one location in Roslyn (Washington);two or three in Nile (Washington);one in Montana.Numbers inside parentheses are ranks of days when data were not normal. Utetes tabellariae eclosion is reported in terms of the number of days after fly puparia formed.

Ninety-two and 77 fly puparia were recovered from soil in the 150-day and 120-day treatment cups, respectively. One live fly pupa was found in the 120-day chill treatment, while two dead adult U. tabellariae were found inside fly puparia in each treatment. Based on the number of dead and eclosed U. tabellariae ( Fig. 1 ), 84.6 and 81.8% of 150-day and 120-day chill U. tabellariae , respectively, survived the experimental treatments and eclosed in the study.

Figures

Fig. 1. Eclosion times of female and male Rhagoletis tabellaria and the parasitoid wasp Utetes tabellariae collected from Washington and Montana, United States of America, after (A) 195-day chill treatment at 4.8 °C and maintenance at 23.2 °C (three sites) and (B) 150-day (three sites) and (C) 120-day chill treatment (two sites) at 2.7 °C and maintenance at 24.3 °C. Puparia were held for 14 days at 22–24 °C before chilling. Numbers with asterisks above bars indicate peak eclosion days for R. tabellaria.