Biology and demography of the dubas bug, Ommatissus lybicus (Hem.: Tropiduchidae), at three constant temperatures

Abstract

Biology and demography of Ommatissus lybicus de Bergevin was studied under controlled conditions at 25 ± 1, 30 ± 1 and 35 ± 1ËC and 60 ± 5% RH and 16: 8 L: D. Forty eggs of the pest (0-24 h old) were used in each temperature treatment. Developmental time was obtained 82.48 ± 0.72, 75.79 ± 0.55 and 89.85 ± 0.71 days at 25, 30 and 35ËC, respectively. Moreover, at 35ËC, most of the biological activities of the dubas bug were disrupted and individuals, especially females, incurred relatively high mortalities. Female life span was significantly higher at 25ËC (108.21 ± 1.33 days) comparing to that of the other temperatures. The net reproductive rate (R0) was 45.93 and 52.31 at 25 and 30ËC; however, it extremely decreased at 35ËC (5.82). The intrinsic rate of increase (rm) was 0.054, 0.062 and 0.029 at 25, 30 and 35ËC, respectively. Similarly, doubling time (DT) was also close at 25 and 30ËC (14.2 vs 12.3 days) but it increased dramatically at 35ËC (29.27 days). Based on life table parameters observed, it was concluded that 30ËC could be an optimum temperature for the biological activities of O. lybicus

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