Habitat alteration influences male signalling effort in the Australian desert goby

Male sexual signals provide vital information about the quality of the signaller and can have important consequences for male reproductive success. Habitat changes, however, are expected to affect male sexual displays. An important question, therefore, is to determine if and how such sexual displays are adjusted to changes in the signalling environment, especially in highly dynamic systems or those affected by human-induced environmental change. Desert, rivers, and springs are among the world’s most threatened habitats. Many of these fragile water bodies are being overwhelmed by invasive weeds and excess primary productivity as an indirect result of human agricultural demand for freshwater. Here, we investigated the effects of altered habitat on the courtship effort of male desert gobies, Chlamydogobius eremius. Male courtship effort was observed in an environment that was either dominated by bulrush (Typha sp.) or modified by increased algal turbidity (Scendesmus sp.). We found that males that were exposed to an environment dominated by bulrush spent more time courting in these environments compared with environments that were unaltered. In contrast, males that were exposed to environments modified by increased algal turbidity not only took longer to initiate courtship but also spent less time courting females. These results suggest that different habitat alterations can have important consequences for the reproductive behavior of affected organisms and, ultimately, the direction of sexual selection.