Multi-level analysis of reproductive changes in honey bee queens (Apis mellifera L.)
Open Access
- Author:
- Niño, Elina Lastro
- Graduate Program:
- Entomology
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- March 02, 2012
- Committee Members:
- Christina M Grozinger, Dissertation Advisor/Co-Advisor
Diana Lynn Cox Foster, Committee Member
James Harold Marden, Committee Member
James Homer Tumlinson Iii, Committee Member
Anita Collins, Special Member - Keywords:
- honey bee queen
mating
reproduction
pheromone
semen
instrumental insemination - Abstract:
- Mating is an intricate process that causes many changes on behavioral, physiological, and molecular level in females of sexually-reproducing species. Here, I study factors involved in triggering and maintaining reproductive changes in honey bee queens. These changes can be regulated by multiple factors including manipulation of the reproductive tract, insemination volume, and seminal fluids. In honey bees, carbon dioxide, which is used as an anesthetic during instrumental insemination, can also trigger post-mating changes. Previous studies on honey bees suggest that insemination volume and seminal fluid components both play a role in triggering queen post-mating changes. However, these studies only examined changes in newly mated/inseminated queens and did not directly uncouple the effects of volume and substance. The long-term effects on queens that have reached their final reproductive state – egg-laying – had not been previously characterized. By manipulating the mating process I examined the factors causing immediate behavioral changes and longer-term physiological and molecular changes in queens that reached their final reproductive state of high ovary activation. In chapter 1, I examined the behavioral (mating flights and egg-laying), physiological (ovary activation), and molecular (gene expression) changes in the queens treated with CO2 alone and queens treated with both CO2 and physical manipulation. In chapter 2, I used the same parameters to characterize the queens inseminated with low and high volumes of either semen or saline. My data indicate that CO2, physical manipulation of the genital tract, and insemination volume cause early behavioral changes, while seminal fluid components play a role in maintaining long-term physiological and transcriptional changes. Mating also causes changes in production of queen pheromones which are important for regulating the behavior and physiology of workers, as well as overall colony organization. Therefore, an important question is whether or not mating quality can have long-term effects on pheromone production as well as on queen-worker interactions. Indeed, in chapter 3 I found that the above mentioned factors have distinct effects on two different pheromone producing glands in queens, and workers can detect these differences. Furthermore, in chapter 4 I demonstrated that the queen insemination volume affected worker behavior and physiology in colonies, as well as queen overwintering survival. In conjunction with previous studies, my results show that multiple factors are involved in regulating short- and long-term post-mating changes in honey bee queens. More importantly, in social insects, this not only affects the reproductive female, but can alter social interactions in entire colony by altering pheromone communication systems. The results of my dissertation will lead to improved breeding techniques of honey bees and other agriculturally important insects, and it will also provide fundamental insights into insect reproduction in general.