|Bowsher, Julia - North Dakota State University|
|Slater, Garett - North Dakota State University|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/14/2017
Publication Date: 11/5/2017
Citation: Bowsher, J., Slater, G., Yocum, G.D. 2017. Diet quantity influence phenotypic dimorphism during honey bee (Apis mellifera) caste determination [abstract]. Entomological Society of America Annual Meeting. Denver, CO. November 5-8, 2017. Poster SD1857.
Interpretive Summary: .
Technical Abstract: Queen and worker honey bees are genetically analogous, but morphologically and physiologically different. Nutritional differences in larval diets regulate caste determination. Our recent work indicates diet quantity has a strong influence on caste in honeybees, and that queen induction can occur in the final instar if larvae are fed ad lib. The aim of this study is to determine whether queen induction during the final instar uses the same cellular mechanisms as had been identified in hive-reared queens. In vitro rearing was used to control for both diet quantity and quality. We quantified transcript levels for target of rapamycin (TOR), and insulin like-receptor-2 (INR-2), juvenile hormone esterase (JHE), forkhead box (FOXO), and S6 kinase 2 (S6K2). In addition, we tested for the presence of a critical weight for inducing metamorphosis. Caste was confirmed using a principal component analysis (PCA) on multiple morphological indicators of caste. Feeding larvae different amounts during the final instar generated queens, intercastes and workers. Our preliminary results indicate the expression levels of TOR, FOXO, INR-2, JHE, and S6K2 were invariant over larval weights from 40mg to 240mg, which included both queen-destined and worker-destined larvae. Constant gene expression suggests these transcripts do not regulate caste determination during the final instar. Honey bee larvae do not have a critical weight, and induce metamorphosis within a day of food being removed over a wide range of larval weights. These results suggest that body size is tightly associated with food quantity, and that caste remains flexible until the final instar. This research has implications for commercial beekeeping because poor larval nutrition may impact queen quality.