The effect of food type on phenotypic plasticity of sword tail, Xiphophurus helleri, during early ontogeny

Phenotypic plasticity is an important mechanism of phenotypic adaptation in response to environmental conditions. This study was conducted to investigate the effect of food type on the body shape of swordtail, Xiphoohurus helleri, during early development using geometric morphometric method. For this purpose, two treatments including feed by Artemia naupli and commercial Biomar diet were used in three replicated during two months. The results showed that feeding by Artemia naupli is led to (1) more ventral position of the snout (terminal mouth), (2) decreasing body depth, (3) elongation of dorsal fin and (4) increasing tail length in compared to those fed by commercial diet. Therefore, the results revealed that food type has a significant effect on the body shape of swordtail during early development and body shape can be changed due to feed type.