Demographic parameters and reproductive performance of the assassin bug Sycanus dichotomus Stal. fed on mealworm Tenebrio molitor L.

The reproductive performance and demographic parameters of Sycanus dichotomus Stal. fed on mealworm Tenebrio molitor L. were studied in the laboratory under the ambient environment of 28 ± 2°C, 70%-90% RH and 12 hr photoperiod. Eggs that were laid in tight clusters of 15-130 eggs per cluster hatched within a mean of 19 days with 6.27% hatchability. The majority of the eggs that were in small clusters were infertile, while larger uniform clusters contained a higher percentage of fertile eggs. There were five nymphal instars. All nymphal stages were reddish in colour. The mean longevity was two to three weeks each for the first to third instars, while at least one week each was needed for the fourth and fifth instars. The total developmental time from egg to adult took 87 days with the females reaching adulthood three days sooner than the male. Adult females survived for an average of 197 days with a median natural mortality (NM50) value of 150 days, while the males endured for an additional 13 days with NM50 value of 165 days. Adults were observed to engage in repeated mating for one week before females proceeded to lay eggs by the third week of post-emergence, with oviposition duration lasting for 186 days. A mean total of 959 eggs were produced during a female’s life-span. The age-specific life table revealed a high rate of combined first and second nymphal mortality, amounting to 63.0%. Pertinent life table parameters, Ro of 137, rm of 0.190 and l of 1.138, were achieved within a generation time of 38.2 weeks, allowing the population to double in 5.4 weeks.