Species recognition can often play a key role in female mating preferences. Far less is known about conspecific mate recognition from the male perspective. In many closely related taxa, females exhibit few obvious visual differences and males might have to attend to chemical cues in mate recognition, a possibility that has rarely been explored in vertebrates. Here, we examine male species recog...

In Xiphophorus, the causative genetic information for melanoma formation has been assigned by classical genetics to chromosomal loci, which are located on the sex chromosomes. In our attempts to molecularly clone these melanoma-determining loci, named Tu, we have looked for restrictionfragment-length markers (RFLMs) linked to the Tu loci. These RFLMs should be useful in obtaining a physical map...

The knowledge of nutritional requirements in ornamental fish species is essential to improve the productive development; however, the nutritional information of these species is scarce and sometimes this information is extrapolated from results obtained from nonornamental fish species. In ornamental fish, a correct formulation of the diet improve the nutrient digestibility and supply the metabo...

Sperm competition is expected to favour the evolution of traits that influence the performance of sperm when they compete to fertilize a female's eggs. While there is considerable evidence that selection favours increases in sperm numbers, much less is known about how sperm quality contributes towards competitive fertilization success. Here, we determine whether variation in sperm quality influ...