Age-stage, two-sex life table of the biocontrol agent, Altica cyanea on three Ludwigia species

Altica cyanea (Weber, 1801) (Coleoptera: Chrysomelidae) is a biocontrol agent of Onagraceae rice-field weeds, Ludwigia adscendens (L.) Hara, L. parviflora Roxb. and L. octovalvis (Jacq.) Raven in India. Hence, it is relevant to study the life history traits and population growth of A. cyanea on three Ludwigia species using age-stage, two-sex life table. The nutritional and antinutritional contents from leaves of the Ludwigia species were measured to comment on the role of nutrients and antinutrients on growth, development and fecundity of A. cyanea. Total larval developmental time was the shortest on L. adscendens (17.78 +/- 0.22 days), intermediate on L. parviflora (20.35 +/- 0.24 days) and the longest on L. octovalvis (21.98 +/- 0.24 days). Total fecundity was the highest on L. adscendens (147.22 +/- 4.74 eggs/female) followed by L. parviflora (119.28 +/- 4.70 eggs/female) and the lowest on L. octovalvis (89.62 +/- 3.45 eggs/female). The intrinsic rate of increase (r) ranged from 0.0639 to 0.0875 d(- 1), which was the lowest on L. octovalvis and the highest on L. adscendens. Population projection indicates that the population growth would be the fastest on L. adscendens and the slowest on L. octovalvis. The nutrients (lipids, amino acids and nitrogen) and antinutrients (tannins) were higher and lower, respectively, in L. adscendens than the other two Ludwigia species, which influenced faster larval development, higher adult longevity and greater fecundity of A. cyanea on L. adscendens. This study suggested that mass release of A. cyanea could be applied in biocontol program of these three Ludwigia weeds.