Title: Impact of Adult Weight, Density, and Age on Reproduction of Tenebrio molitor (Coleoptera: Tenebrionidae) Authors
Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 19, 2012
Publication Date: July 2, 2012
Citation: Morales Ramos, J.A., Rojas, M.G., Kay, S., Tedders, W., Shapiro Ilan, D.I. 2012. Impact of adult weight, density, and age on reproduction of Tenebrio molitor (Coleoptera: Tenebrionidae). Journal of Entomological Science. 47:208-220. Interpretive Summary: The yellow mealworm, Tenebrio molitor, is mass produced commercially in the US for a varied of purposes. One potential use of the yellow mealworm is as a host for insect-killing (entomopathogenic) nematodes that could be commercialized and used against important agricultural pests such as the plum curculio, the pecan weevil, and the hive beetle. The aim of this study was to improve the rearing technology of this beetle by reducing labor and space to make it economically competitive. This could enable small companies to produce insect-killing nematodes at a reduced price. Our research findings provided information for optimal beetle densities for maximizing mealworm production and optimal cut-out dates to replace reproductive females. Application of these findings to commercial operations could reduce substantially the space required for production while at the same time reducing the labor required for colony maintenance.
Technical Abstract: The impact of adult weight, age, and density on reproduction of Tenebrio molitor L. (Coleoptera: Tenebrionidae) was studied. The impact of adult weight on reproduction was determined in two ways: 1) counting the daily progeny of individual adult pairs of known weight and analyzing the data with linear regression and 2) creating 5 weight classes of 10 mg intervals starting at 60 mg (60-69.9mg) and ending at 100 mg (100-109.9 mg), then the progeny of 10 groups of 5 males and 5 females of each weight class were compared using ANOVA. To determine the impact of adult density on reproduction, adults were grouped at 8 different densities by increasing numbers per box (at 1:1 sex ratio). Weekly progeny production of 8 groups per density treatment was compared using ANOVA. There was no significant relationship between female weight and progeny production in the individual pair analysis. Fecundity was significantly different among weight classes, but the relationship was not linear. Adult density had a significant impact on progeny per female and progeny per unit area. Reproductive output per female decreased as adult density increased. Progeny per unit area increased to a maximum at a density of 14 adults / dm2 and then declined sharply. Adult age had a significant impact on reproduction. The highest reproductive output occurred at 2 and 3 wk of age and was significantly higher than at any other age. The potential to manipulate adult density and age to maximize production of T. molitor larvae is discussed