Cold storage of the predatory bugs Podisus maculiventris (Say) and Podisus sagitta (Fabricius) (Heteroptera : Pentatomidae)
1993
Clercq, P. de | Degheele, D. (Gent Univ. (Belgium). Faculteit van de Landbouwkundige en Toegepaste Biologische Wetenschappen. Lab. of Agrozoology)
In optimizing the mass rearing of predatory bugs of the genus Podisus different conditions of temperature (4 and 9 degree Celsius) and relative humidity (50-100 per cent R.H.) were evaluated for cold storage in continuous darkness of eggs of Podisus sagitta and of adults of Podisus maculiventris and P. sagitta from laboratory cultures at 23 degree Celsius. Survival of both eggs and adults was reduced when stored at a lower R.H. (50 per cent) and at a lower temperature (4 degree Celsius); humidity proved to be the most critical factor. Survival of P. sagitta eggs during storage was related to egg age. A temperature of 9 degree and a R.H. close to 100 per cent yielded best results. Under these conditions, 1 to 4 day-old eggs could be kept up to 6 days without an adverse effect on viability; however, survival of 0-day-old eggs was low, even for short storage periods. At 9 degree and 75 per cent R.H., adults of P. sagitta could be held for at least 1 month with no negative effects on survival and on post-storage longevity and reproduction. Under similar conditions, adults of P. maculiventris could be stored up to 2 months with a good survival; however, their post-storage longevity and oviposition were reduced in comparison with longevity and oviposition of unstored bugs. In the laboratory, adults of these pentatomids passed cold, dark periods in a quiescent state, rather than in a true diapause.
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