Nutritional value of pupae versus larvae of Tenebrio molitor (Coleoptera: Tenebrionidae) as food for rearing Podisus maculiventris (Heteroptera: Pentatomidae)

Authors: Morales Ramos, Juan; Rojas, Maria - Guadalupe; Shelby, Kent; Coudron, Thomas

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/7/2015
Publication Date: 11/30/2015
Citation: Morales Ramos, J.A., Rojas, M.G., Shelby, K., Coudron, T.A. 2015. Nutritional value of pupae versus larvae of Tenebrio molitor (Coleoptera: Tenebrionidae) as food for rearing Podisus maculiventris (Heteroptera: Pentatomidae). Journal of Economic Entomology. 109(2):564-571.

Interpretive Summary: The spined soldier bug is an important predator of caterpillar and beetle pests and it is used as a biological control agent in the United States. The spined soldier bug is produced commercial and sold by many biocontrol companies in the U. S. and the European Union. Currently this important biological control agent is being reared using caterpillars as prey. Production of caterpillars can be expensive and labor intensive. An alternative prey that can be produced cheaply could benefit the biological control industry and provide with inexpensive alternatives to chemical control of caterpillar pests. In our study we tested the viability of the yellow mealworm as factitious prey item to produce the spined soldier bug. We compared the value of larvae and pupae of the yellow mealworm providing nutrition for development and reproduction of the spined soldier bug. Chemical analyses of larvae and pupae of the yellow mealworm provided information on nutrient content to correlate the prey's nutrient profile with the biological response of the predator. Our results show that pupae were superior to larvae as prey for the predators. Pupae had higher content of protein and carbohydrates and lower content of fat as compared with larvae of the yellow mealworm. The yellow mealworm is cheaper to grow than caterpillars and provides an inexpensive prey alternative to grow the spined soldier bug. Additionally, the yellow mealworm is commercially produced in the U. S. and Europe providing a reliable source of prey to grow this predator. Results of this study could benefit the biological control industry and provide economic alternatives to chemical pest control to growers.

Technical Abstract: Factitious prey are often more suitable for use in mass production of beneficial insects than natural prey. Life table analysis yielded demographic parameter values that indicate Tenebrio molitor (L.) pupae are promising as factitious prey to mass produce Podisus maculiventris (Say) and are more suitable prey than the larvae. P. maculiventris developed faster (23.2 vs. 25.5 d), weighed more (females 80.9 vs. 66.6 mg and males 64.7 vs. 53.7 mg), and had a higher survival rate (0.88 vs. 0.7), fecundity and reproductive output (87.1 vs. 22.8 eggs/female) when reared on pupae compared with larvae of T. molitor. The total protein and soluble protein contents were higher in T. molitor pupae (60.2 and 23 %) than larvae (53.1 and 14.4 %). In contrast, the lipid content was lower in pupae (32.1 %) than larvae (35.9 %) and larvae had more polyunsaturated fatty acids (83.6 vs. 56.6 mg/g) and less oleic (0.1 mg/g) and steric (6.1 mg/g) acids than pupae (37.3 and 12.3 mg/g, respectively). Pupae also had more sugar content than larvae. Differences in chemical composition, chemical structure and the absence of gut content are potential factors that make the pupal stage a better food source.