Eric J. Villavaso

CO2 Release in Groups of Reticulitermes virginicus (Isoptera: Rhinotermitidae)

Abstract CO2 release rates were measured from groups of 10 Reticulitermes virginicus Banks workers, soldiers, and nymphs. For workers, Vijco2, (μl·mg−1·h−1) increased linearly with temperature between 16.2 - 30.4°C. Vijco2 recorded at ≈20°C was 0.177 ± 0.005 μl·mg−1·h−1 for soldiers and 0.219 ± 0.027 (μl·mg−1·h−1 tor nymphs. Assuming a similar slope of temperature increase in Vijco2 for all castes, predicted mass-corrected CO2 release values for grouped R. virginicus workers, soldiers and nymphs at 23.6°C were 27, 52 and 27% lower than literature values for the same castes of R. flavipes measured individually at that temperature. CO2 release rate (μl·mg−1·h−1) for R. virginicus nearly doubled over the 20°C to 30°C temperature range (Q10 = 1.91), similar to literature values for Zootermopsis nevadensis (Hagen) over the same range. For all temperatures except 25.2°C, CO2 release rate (in μl·h−1) increased significantly with mass, with coefficients ranging from 0.123 (16.2°C) to 0.599 (30.4°C).

Effect of Release Time on Recovery of Tagged Irradiated Boll Weevils

Irradiated Anthonomus grandis Boheman, tagged with 32P, were hand-released in cotton fields during the morning, noon, and evening. Equal numbers of boll weevils were recovered irrespective of release time. Within 1 day after release, ca. ⅓ of all released weevils had disappeared from the field; by the 4th day, only 38.0% live weevils were recovered. Tagging did not reduce survival of irradiated weevils.