Body size and lifespan are condition dependent in the mealworm beetle, Tenebrio molitor, but not sexually selected traits

• Published in: Behavioral ecology and sociobiology Vol. 72; no. 3; pp. 1 - 8
• Main Authors: McConnell, Murray W., Judge, Kevin A.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer 01.03.2018; Springer Berlin Heidelberg; Springer Nature B.V
• Subjects: Animal behavior; Animal Ecology; Attraction; Beetles; Behavioral Sciences; Biomedical and Life Sciences; Body size; Diet; Fecundity; Females; Fitness; Insects; Larvae; Life history; Life Sciences; Life span; Males; Nutrient deficiency; Original Article; Pheromones; Predictions; Resource allocation; Sexual selection; Tenebrio molitor; Zoology; Direct benefits; Sexual selection; Condition dependence; Pheromones; Lifespan
• ISSN: 0340-5443; 1432-0762
• DOI: 10.1007/s00265-018-2444-3

Traits under strong directional selection are predicted to be condition dependent and thus increase in development when an organism acquires more resources. This prediction has been tested for a variety of traits, particularly those under precopulatory sexual selection. However, few studies compare the condition dependence of a variety of phenotypic traits, potentially subject to different selective forces. Here we examine the condition dependence of several important life history traits, including those under both pre- and postcopulatory sexual selection, in the mealworm beetle, Tenebrio molitor. We manipulated condition by randomly assigning larvae to one of high-, medium- or low-quality diets. For males reared on the three diets, we measured the following: (a) adult body size and lifespan, (b) pheromone attractiveness, (c) weight of their ejaculate transferred to females and (d) fecundity of their female mates. Males raised on a high-quality diet were larger and lived longer than males raised on mediumand low-quality diets. Although females were significantly attracted to male pheromones, there were no significant differences amongst condition treatments in male attractiveness nor ejaculate transfer. Furthermore, mates' fecundity was also not affected by male condition. We discuss these results considering previous work on trade-offs and condition dependence of life history traits.