When a male detects signs of a female nearby he checks whether she is of the same species and whether she is ready to mate ; for example in species that produce webs or `` safety ropes '' , the male can identify the species and sex of these objects by `` smell '' .
When a male detects signs of a female nearby he checks whether she is of the same species and whether she is ready to mate ; for example in species that produce webs or ` safety ropes ' , the male can identify the species and sex of these objects by smell .