Supplemental diets containing yeast, sucrose, and soy powder enhance the survivorship, growth, and development of prey-limited cursorial spiders

Abstract

We examined the effects of a supplemental diet mixture (SDM) and its individual ingredients (sucrose, yeasts, and toasted soy flour) on the survivorship, growth, and development of a cursorial spider, Hibana futilis Banks (Anyphaenidae). Some treatments included limited numbers of Helicoverpa zea eggs, a favored prey. This approach highlighted the relative nutritional contributions of the supplemental diet ingredients, especially under conditions of prey limitation, and showed whether these spiders could be reared on minimal prey augmented with supplemental diet. Spiders fed either 5 or 15 eggs became prey-limited during their first and second molts, respectively. When deprived of prey but provisioned with either sucrose or SDM, spiders persisted as first instar nymphs for weeks, but while sucrose-fed nymphs never molted, those fed SDM typically molted 2–3 times. When SDM was added to the diet, spiders that had fed on as few as 50 eggs could reproduce successfully. Binary mixtures of sucrose plus either baker’s yeast (Saccharomyces cerevisiae Meyen ex E.C. Hansen) or toasted soy flour were more effective in promoting growth and development in prey-limited spiders than any of the three ingredients of SDM alone. Active baker’s yeast was more effective than dried powdered brewer’s yeast at supporting development. These results suggest two possibilities for managing cursorial spiders: (1) Supplemental diet mixtures could be applied as a food spray to promote their conservation in crops; and, (2) A mass rearing diet could be made from a minimal amount of prey plus two or three inexpensive, supplemental diet ingredients.