Meeting Abstract

23.1  Monday, Jan. 4  Size matters: seasonal plasticity of development in a diapause-destined moth, Helicoverpa zea. CLEMMENSEN, S F*; HAHN, D A; University of Florida; University of Florida sclemmensen@ufl.edu

Seasonality presents a problem for organisms because inhospitable conditions like cold temperatures can adversely affect survival, development, and reproduction. Many species mitigate this environmental stress by undergoing a dormant phase, or an arrested period of development – insect diapause is one example of this type of dormancy. While diapause is advantageous it also has costs. For example, if diapause occurs in a stage where an insect can not feed, such as the pupal stage, the individual must contain all the resources needed to both maintain diapause and finish development. One potential strategy for reducing the costs of diapause is accumulating more resources (e.g., lipid stores) prior to entering the non-feeding diapause stage. We expect that there are several different ways that lipid stores may be increased: 1) becoming both larger and proportionally fatter, 2) becoming proportionally fatter without increasing size, and 3) becoming smaller and proportionally fatter. We examined lipid storage and lean mass accumulation in diapause-bound Helicoverpa zea (Lepidoptera: Noctuidae) moths compared to non-diapause individuals. Our results support our first possible scenario, wherein diapause-destined pupae were both larger and proportionally fatter. We also showed that the critical weight for pupation was increased in diapause-inducing conditions, and diapause incidence increased with peak larval weight. Our results indicate that H. zea adjust their developmental trajectory when entering the diapause preparatory program.