Age-stage, two-sex life table of <i>Parapoynx crisonalis</i> (Lepidoptera: Pyralidae) at different temperatures

<div><p><i>Parapoynx crisonalis</i> is an important pest of many aquatic vegetables including water chestnuts. Understanding the relationship between temperature variations and the population growth rates of <i>P</i>. <i>crisonalis</i> is essential to predicting its population dynamics in water chestnuts ponds. These relationships were examined in this study based on the age-stage, two-sex life table of <i>P</i>. <i>crisonalis</i> developed in the laboratory at 21, 24, 27, 30, 33 and 36°C. The results showed that the values of <i>S</i>_<i>xj</i> (age-stage–specific survival rate), <i>f</i>_<i>xj</i> (age-stage-specific fecundity), <i>l</i>_<i>x</i> (age specific survival rate) and <i>m</i>_<i>x</i> (age-specific fecundity) increased as the temperature rose from 21 to 27°C, then decreased from 30 to 36°C. Temperature also had a significant effect on the net reproductive rate (<i>R</i>₀), gross reproductive rate (<i>GRR</i>), intrinsic rate of increase (<i>r)</i> and finite rate of increase (<i>λ</i>). The value of these parameters were at low levels at 21, 33, and 36°C. Further, the <i>r</i> value decreased as the temperature rose from 24 to 30°C, while the <i>GRR</i> reached its highest level at 27°C. The results indicated that optimal growth and development of <i>P</i>. <i>crisonalis</i> occurred at temperatures between 24°C to 30°C when compared to the lowest temperature (21°C) and higher temperatures of 33°C and 36°C.</p>