Abstract

Temperature can affect the predation potential of predators. The temperature-dependent development of Nabis capsiformis (Geram) was studied in the laboratory in six constant temperatures (18, 22, 24, 28, 31 and 33 °C) on green pods of bean (Phaseolus vulgaris, L.) infested with pea aphid, Acyrthosiphon pisum (Harris). Developmental times in days for separate immature and total development (egg to adult) were inversely proportional to temperature between 18 and 28 °C but increased at 31 °C. Bugs did not manage to complete development at 33 °C. Thermal parameters were estimated by fitting two linear (common and Ikemoto- Takai) models and four non-linear (Taylor, Hilbert – Logan, Briere and Lactin) models to the data. The lower developmental thresholds, calculated using the common linear model and Ikemoto- Takai model for egg, total nymph, and total development were 15.91, 10.01, and 11.76 °C and 14.74, 10.55, and 12.07 °C respectively. The thermal constants for total development were estimated 341.29° – days with common linear model and 313.40° – days with Ikemoto – Takai model. Four non linear models, Taylor, Hilbert and Logan, Briere and Lactin fitted the data well as measured by the ‘‘z weight’’ indicator. Temperature threshold parameters for these non linear models (T(min), T(opt), and T(max)) were estimated for eggs, total nymphal stages, and total development time (egg to adult). The Taylor model is recommended for the description of temperature-dependent development of N. capsiformis. The optimal temperature for the development of eggs, the five nymphal instars and the egg-adult period predicted by this model ranged between 29 and 30 °C. Results from this study will provide basic information for the development of predictive models of the seasonal progress of this natural enemy.

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