Sodium polyacrylamide polyacrylate, a gelling agent in diets for cabbage looper, omnivorous looper and western avocado leafroller

Abstract

AbstractIngredient substitutions for agar or carrageenan in artificial diets for lepidopterous larvae were evaluated. A sodium polyacrylamide polyacrylate gelling agent, Water‐Lock G‐400, was compared with agar for solidifying diets of the cabbage looper, Trichoplusia ni (Hübner), omnivorous looper, Sabulodes aegrotata (Gueneé), and the western avocado leafroller, Amorbia cuneana Walsingham. Water‐Lock G‐400 is considerably less expensive than agar or carrageenan, it does not require heating to gel, and it is made from a dependable supply of agricultural starch.Sabulodes aegrotata pupae from larvae reared on agar were significantly heavier than those reared on Water‐Lock G‐400. However, the remainder of the variables observed (larval survival, developmental times, fecundity, sex ratio and pupal weights for A. cuneana and T. ni) were all independent of diet. Decreasing the total amount of ingredients in a Water‐Lock‐G‐400 diet produced fewer and smaller T. ni pupae than did an agar diet when the larvae were reared using a mass production protocol. However, these lower values were still above acceptable levels for mass production and reduced the cost of diet production by 65%.Further ingredient substitutions impaired larval development (i.e., replacing pinto beans with soy protein or combinations of soy protein and α‐cellulose), while others did not (i.e., excluding pinto beans and reducing water content and replacing pinto beans with α‐ cellulose or corn cob grits). Moisture control by adding corn cob grits to diets increased the yield of pupae, while removing water from diets increased survivorship and the yield of pupae.