The effect of light during embryonic development on laterality and exploration in Western Rainbowfish

Several factors affect the development of lateralization such as hormones and light exposure during early development. Laterality also often correlates with other behavioral traits. To examine whether there is a common mechanism underlying the development of laterality and other behaviors, we manipulated laterality by exposing embryos of the Western rainbowfish (Melatotaenia australis) to light or continuous darkness during early development and determined whether a shift in laterality was associated with a change in behavior in a novel environment test at two different ages. We found that exposing eggs to darkness led to offspring that displayed significantly less lateralized behavior in the mirror test two weeks after hatching than offspring from eggs exposed to light. Interestingly, the effects of rearing condition were lost by 3 months of age. These data suggest that exposure to light can influence laterality very early in development, but such bias can be overwritten by developmental processes post-hatch. Moreover, our manipulation of laterality apparently had no influence on exploration suggesting independent causal mechanisms. The experimental manipulation of light exposure during development could be a useful tool for enhancing individuals with a specific laterality and behavioral traits to aid future research into the causes and consequences of laterality.

Automated summary

Several factors, such as hormones and light exposure, affect the development of lateralization. The study manipulated laterality by exposing embryos to light or darkness and examined the association between a shift in laterality and behavior in a novel environment test. It was found that light exposure influenced early development of laterality, but this bias was lost by 3 months of age. The study suggests that light exposure during early development can influence laterality and provides a useful tool for future research on the causes and consequences of laterality.