Microplastic ingestion alters the expression of some sexually selected traits in a model fish guppy (Poecilia reticulata Peters 1859)

A study was conducted to investigate the effects of microplastics (<5 mm) and macroplastics (>5 mm) on some phenotypic traits of guppy (Poecilia reticulata). Juvenile male guppies, fed with a commercial diet, were reared for 70 days in aquariums under three different experimental treatments: 1) control (no plastic); 2) microplastic; and 3) macroplastic. The findings revealed that microplastic-treated males had significantly higher mortality, shorter standard length, smaller body area, a limited number of sperm bundles and sigmoid displays, and less sexual interest than macroplastic and no-plastic treated males. The analyses showed no significant variation in tail length, gonopodial thrusts, or different color patterns among the treatments. Taken together, these findings show how microplastic pollution can influence the survival, growth, and reproductive traits of a fish species; this must be considered seriously, as other aquatic animals could be saved by reducing the amount of plastic waste in different aquatic environments.