Shoaling Behavior and Boldness in Guppies Descended from High and Low Predation Populations

Open Access
Cooper, Hannah Marie
Area of Honors:
Bachelor of Science
Document Type:
Thesis Supervisors:
  • Victoria Anne Braithwaite Read, Thesis Supervisor
  • Lester C Griel Jr., Honors Advisor
  • Dr James Marden, Faculty Reader
  • shoaling behavior
  • boldness
  • temperament
  • Poecilia reticulata
  • guppies
  • predation
This experiment examined the behavioral and cognitive traits impacted by predation pressure using female guppies descended from fish originally obtained at high and low predation sites from rivers in Trinidad. Previous studies have shown that guppies will preferentially shoal with larger groups, and are able to differentiate between groups of two and three fish. We evaluated the impact of high and low predation ancestry and temperament on the ability to, and preference for, selecting a larger shoal. Domesticated guppies were also evaluated for these traits and compared to those descended from wild-caught fish. Temperament was assessed using an open field trial prior to shoaling trials to determine whether the fish preferred to shoal with a group of two guppies or a group of three guppies. We hypothesized that the different populations would vary in their temperament, and that temperament would affect shoaling preferences. We also predicted that shoaling preference in high predation descendants would be to shoal with the larger group because it provides protection from predators (Seghers 1974). The temperament trials showed there was no difference in the boldness of the high and low predation populations and the domestic guppies, nor were there population differences in shoaling behaviors. Our results did show, however, that bolder guppies spend less time shoaling with the larger group, and prefer smaller groups of conspecifics. Due to the small sample size, additional trials are needed to confirm that there are no population differences in temperament or shoaling behavior between these groups. This will indicate whether shoaling behavior is strongly selected for in nature or whether the shoaling preferences are lost when animals are removed from a pressured environment.