Question

How do communication signals participate in reproductive isolation? Give one example of a signal that is species-specific. Why are some signals individually specific?

Answer 1

Interpopulationalvariation in sexual chemical signalsmay provide the basis of premating reproductive isolation and speciation in many animals. As a way to maximise the efficiency of signals for communication in different environments phenotypic plasticity in sexual signals could play a key role in initial signal divergence. These differences can be later amplified by sexual selection leading to differences in mating preferences which could preclude mating between populations and lead to speciation processes.

In many lizards , intraspecific communication and sexual selection are based on chemical signals secreted by specific glands. For eg, chemical compounds secreted by femoral gland of males can convey information about social status and genetic quality of a male. We hypothesized that interpopulational variations in femoral gland secretions within the same species might lead to reproductive isolation and thus promote speciation processes.

The ​​​Podarcis hispanica, Iberian wall lizard is a small diurnal lozard living in rocky habitats . Chemosensory recognition is well developed in this .It can discriminate between sexes by chemical cues alone. Chemical cues of males mainly from femoral gland secretions are important un male-male interactions and in female mate choice decisions. This raises the possibility that this lizards use chemical sexual signals to discriminate between populations, which might lead to reproductive isolation.