Multiple animals, specifically invertebrates and insects, use various communication signals allowing them to mate only with the individuals of the same species. For example, many male insects use chemical signals, sounds, vibrations and other signs to attract females of the same species. As a result, the signals help females or males to distinguish mates from the related species that are similar by appearance and behaviour but produce different communication signals. This process prevents hybridization between the species. Sound communication by male wolf spiders is an example of reproductive isolation. Females respond to males that produce specific acoustic signals that induce receptivity. Females of the related species of the wolf spiders do not respond to the signals although no physical barriers are present and hybrids are viable. Some signals, specifically chemical attractants of insects, may reflect the features of male or female showing its viability and quality of genes. As a result, such individual signals inform the partner if the individual can give high-quality viable offspring.