Demography of the Leafminer ParasitoidGanaspidium utilisBeardsley (Hymenoptera: Eucoilidae) at Different Temperatures

Demographic parameters, reproductive pattern, and heterogeneity for the leafminer parasitoidGanaspidium utilisBeardsley (Hymenoptera: Eucoilidae) were determined in the laboratory at 16, 27, and 32°C usingLiriomyza trifolii(Burgess) with “Henderson” bush lima beans as the host. Development and progeny production did not occur at 16°C. Mean developmental time was significantly shorter (13.2 days) at 32°C than at 27°C (18.4 days). Preadult cumulative survival rates at 27°C (62%) and 32°C (43%) were significantly different. Male and female longevities were similar. AdultG. utilislived a maximum of 23 days at 16°C, 13 days at 27°C, and 8 days at 32°C. Total mean lifetime progeny production per femaleG. utilisranged from 68.50 progeny at 32°C to 115.10 progeny at 27°C. Heaviest progeny production occurred during Days 2 and 3 of a femaleʹs life at 32 and 27°C, respectively. Of the total progeny produced, the female percentage ranged from 47 at 27°C to 49 at 32°C. Mean generation time was 15 days at 32°C and 21 days at 27°C. Intrinsic rate of increase varied from 0.19 at 27°C to 0.23 at 32°C. In the stable age distribution, egg percentage was highest (56–58) followed by larval stage (36–37), whereas pupal and adult stages each only represented 3 to 4. Age-by-parity relations demonstrated that timing and magnitude of reproduction were influenced by temperature.