[On the Preferred Temperature and water economy of Oncopeltus fasciatus Dall. (Heteroptera: Lygaeidae)].

The "Preferred Temperature" of Oncopeltus fasciatus has been investigated. In a temperature gradient the bugs disperse within a broad range from 12,5 to 35°C (=Range of Preferred Temperature). Within this special range each individual selects its own smaller Preferred Temperature (P.T.), depending on its physiological condition. After water deficiency for 48 hrs. the bugs choose a P.T. of a range between 15-17,5°C. At temperatures below 30°C Oncopeltus fasciatus forms aggregations because the bug exhibits a "subsocial" behaviour. At temperatures above 30°C no aggregation is formed. At a range between 35-100% the Relative Humidity (R.H.) has no meaning for the duration of life, also in combination with water deficiency. But the active uptake of water seems to be the dominant factor for the survival of the seed-sucking bug Oncopeltus fasciatus.