BIOLOY AND BEHAVIOUR OF Dysdercus ruficollis (LINNAEUS, 1764) (HEMIPTERA: PYRRHOCORIDAE IN LABORATORY CONDITIONS

ABSTRACT

The objective of this work was to study the biology and the behaviour of Dysdercus ruficollis (Linnaeus, 1764) (Hemiptera: Pyrrhocoridae), one important pest of cotton (Gossypium spp.). In laboratory conditions, 50 insects were reared at temperature of 25 ± 1 ^oC, 80 ± 3 % RH and photoperiod 12 L : 12 D. The females realized postures during the day and night periods. The eggs that gave origin to the males and the eggs that gave origin to the females presented the same incubation period, 6.00 days. Five nymphal stages occurred. The nymphal period, the longevity and the males life cycle were 31.35; 44.25 and 81.60 days, respectivilly and the females were of 32.50; 49.17 and 87.67 days, respectivilly. The median period of precopula was of 3.70 days, the copula one was 2.34 days and the no copula one was 3.64 days. The median period of pre-posture was of 9.60 days, the posture one was 12.70 days and the post-posture one was 3.40 days. The females realized in average 3.65 postures and there was a decrease of the total number of eggs from 1^st to the 5^th posture. The fecundity average was 273.35 eggs and the median number of eggs per posture was 74.89. The fertility average was of 5.30 eggs per female, the median number of fertile eggs per posture was 1.45 and the fertility rate was 1.94 %.

Key words
pest; cotton-tree; bug.