Table 5. Comparison of lateral dispersal of Heterorhabditis bacteriophora and Steinernema carpocapsae in the presence of mobile and non-mobile hosts.
| Species | H. bacteriophora | S. carpocapsae | Linear term | Quadratic term |
|---|---|---|---|---|
| Host insect | Dead G. mellonella baits (Mean ± SE) | |||
| Non-mobile | 0.16 ± 0.02 | 0.40 ± 0.06 | ** | ** |
| (Y = 0.025 + 0.002 Time + 0.173 x 10-4 Time2; r2 = 0.06; P < 0.01) | (Y = 0.144 + 0.018 Time - 0.221 x 10-3 Time2; r2 = 0.03; P = 0.36) | |||
| Mobile | 0.29 ± 0.04 | 0.49 ± 0.04 | NS | NS |
| (Y = 0.062 + 0.015 Time - 1.764 x 10-4 Time2; r2 = 0.03; P = 0.24) | (Y = 0.464 + 0.005 Time - 8.132 x 10-5 Time2; r2 = 0.02; P = 0.39) | |||
| Linear term | ** | NS | ||
| Quadratic term | ** | NS | ||
| Host insect | Percentage of infective juveniles (Mean ± SE) | |||
| Non-mobile | 2.71 ± 0.94 | 26.62 ± 12.57 | ** | ** |
| (Y = 0.021 + 6.318 x 10-4 Time - 1.176 x 10-5 Time2; r2 = 0.04; P = 0.61) | (Y = 0.848–0.022 Time + 0.141 x 10-3 Time2; r2 = 0.05; P = 0.15) | |||
| Mobile | 6.64 ± 1.75 | 14.92 ± 4.21 | ** | ** |
| (Y = 0.293–0.011 Time + 9.517 x 10-5 Time2; r2 = 0.21; P < 0.01) | (Y = 0.631–0.022 Time + 1.891 x 10-4 Time2; r2 = 0.20; P < 0.01) | |||
| Linear term | ** | NS | ||
| Quadratic term | ** | NS | ||
Mean (±SE) number of dead Galleria mellonella baits from the collected soil core samples and mean (±SE) percentage of infective juveniles (IJs) of Heterorhabditis bacteriophora and Steinernema carpocapsae dispersed to 2 cm wide annuli at all three distances, 3.8, 7.6 and 11.4 cm over a period of 12 to 72 hr in the presence of mobile and non-mobile host in the microcosms containing autoclaved field soil with vegetation. Quadratic regression lines fitted for the mean number of dead G. mellonella baits and mean percentage of IJs of each of the two species dispersed up to 11.4 cm distance from the source cadaver over a period of 72 hr in the presence of mobile and non-mobile hosts are bracketed. Double asterisk (**) indicates the significant difference in the estimated linear and quadratic coefficients between the two species, horizontally and the type of host within a species, vertically (from regression analyses, P ≤ 0.05). NS = P > 0.05.