The influence of water velocity on the display behavior of male guppies, Poecilia reticulata

Abstract

The objective of this experiment was to determine if different water velocities during ontogeny affect male physical condition, male signal intensity and female mating preference in the guppy (Poecilia reticulata). Guppies were raised in aquaria in either high on low water velocities and fed in excess. Analysis of 72 males from four replicates indicated that high velocity males had longer mean displays and spent more total time displaying than low velocity males. These males also had significantly faster swimming speed, wider caudal peduncle, and were attractive to females than low velocity male. There were no differences in display rates, body widths, standard lengths, or copulation attempts between high and low velocity males. These results indicate that water velocity condition during ontogeny act as a proximal factor that influences the display behavior of guppies. Water velocity caused an direct increase in the power of the male display to produce a female sexual response. The morphometric measurements suggest that the proximal mechanism behind the increased display intensity was the increased muscle development of male raised in high water velocities, which resulted in longer prolonged swimming speed and more intense display. Therefore, display behavior of guppy may be a general indication of overall male physical condition.