Table 1.
Results from the competition experiments using isotope labelled males (i.e. 15N or 13C) to determine insemination in spermathecae. Treatments were 1) 15N un-irradiated males : 13C un-irradiated males : females (i.e. control), 2) 15N irradiated males : 13C un-irradiated males : females, 3) 15N un-irradiated males : 13C irradiated males : females. Males were irradiated with 70 or 120 Gy in the pupal stage. For the control treatment 1, the proportion and the number (in between brackets) of spermathecae positive for 15N or 13C, are indicated. For the radiation treatments, spermathecae inseminated by irradiated or un-irradiated males are shown. Spermathecae positive for both isotopes are classified as inseminated by "Both". Those with amounts of isotopes below the detection threshold are classified as 'Neither". N is the total number of spermathecae analysed per row. Individual and pooled (when replicates could be grouped) G-test results for each competition experiment are given (see text for details) with significant differences at * p < 0.05 and ** p < 0.01. Average values for competition experiments (insemination by irradiated or un-irradiated males only) are only given when replicates could be grouped.
| Control | Exp. | Treatment 1 | % 15N (N) | % 13C (N) | % Both isotopes (N) | % Neither isotope (N) | N | G-test 15N vs 13C |
| 1 | 1 | 65 (13) | 20 (4) | 15 (3) | 0 (0) | 20 | 3.62 | |
| 2 | 1 | 60 (12) | 10 (2) | 30 (6) | 0 (0) | 20 | 3.95* | |
| 3 | 1 | 25 (5) | 60 (12) | 10 (2) | 5 (1) | 20 | 2.38 | |
| 4 | 1 | 45 (9) | 45 (9) | 0 (0) | 10 (2) | 20 | 0 | |
| average | n/a | n/a | 14 ± 6 | 4 ± 2 | n/a | |||
| 70 Gy | Exp. | Treatments 2–3 | % Irrad. (N) | % Un-irrad. (N) | % Both isotopes (N) | % Neither isotope (N) | N | G-tests 70 vs 0 Gy |
| 1 | 2 15N | 35 (7) | 35 (7) | 30 (6) | 0 (0) | 20 | 0 | |
| 1 | 3 13C | 15 (3) | 65 (13) | 20 (4) | 0 (0) | 20 | 4.30* | |
| 3 | 2 15N | 15 (3) | 65 (13) | 0 (0) | 20 (4) | 20 | 6.74** | |
| 3 | 3 13C | 35 (7) | 55 (11) | 10 (2) | 0 (0) | 20 | 0.73 | |
| average | 25 ± 6 | 55 ± 7 | 15 ± 6 | 5 ± 5 | 6.63* | |||
| 120 Gy | Exp. | Treatments 2–3 | % Irrad. (N) | % Un-irrad. (N) | % Both isotopes (N) | % Neither isotope (N) | N | G-tests 120 vs 0 Gy |
| 2 | 2 15N | 18 (3) | 65 (11) | 18 (3) | 0 (0) | 17 | 3.29 | |
| 2 | 3 13C | 42 (8) | 53 (10) | 5 (1) | 0 (0) | 19 | 0.20 | |
| 4 | 2 15N | 0 (0) | 95 (19) | 5 (1) | 0 (0) | 20 | 21.07** | |
| 4 | 3 13C | 30 (6) | 65 (13) | 5 (1) | 0 (0) | 20 | 2.38 | |
| average | n/a | n/a | 8 ± 3 | 0 | n/a | |||
n/a: not applicable (replicates could not be grouped based on G-test results)