Various biological characteristics of the soybean pest Riptortus Iinearis (F.) were studied in a series of laboratory and greenhouse experiments. The premating period lasted 89 hours with most of the mating taking place between 12:00 and 20:00 hours. The preoviposition period lasted 118 hours, and most oviposition occurred between 12:00 and 20:00 hours, with a peak between 14:00 and 18:00 hours. Oviposition took place between seven to twelve days after emergence of adult. Eggs were laid singly mostly on leaves and only on soybean plants having pods. Daily removal of eggs from soybean plants resulted in insects laying three times as many eggs as when none were removed. The durations of egg incubation and each nymphal stadium decreased proportionately as temperature increased from 20°C to 35°C. At 20°C durations of egg incubation' and nymphal stadia were 12.75 and 35.47 days, respectively, whereas at 35°C, these periods were 4.13 and 11.52 days, respectively. Fifth instars suffered greater mortality than other instars. The first instar did not feed but feeding activity of the second through the fifth instars progressively increased. The seed size and seed germination rate decreased when R. linearis adults fed on developing seeds from R2 to R7 growth stages. When no food was provided, all adults died within 8 days; provision of green pods or dry seeds lengthened survival periods to as long as 28 to 31 days. Highly significant positive correlations were found between the number of instars and body and antennal lengths.
Fecundity, Temperature effect, Damage, Mating, Feeding habits
