Condition dependence of male nuptial gift construction in the spider Pisaura mirabilis (Pisauridae)

Pisaura mirabilis males offer a prey wrapped in silk as a nuptial gift that functions as a male mating effort. If nuptial gift construction is costly, males in poor feeding condition would invest less in this behaviour than males in good condition. We investigated frequencies and characteristics of gift construction in males under different sexual stimuli and different feeding conditions. We analysed gift construction behaviours of 17 males exposed sequentially to three treatments: female silk (S), female silk plus female (SF) and no female cues (control; C). The same individuals were first tested when in good feeding condition (young/satiated) and subsequently in poor feeding condition (old/starved). A separate group in good feeding condition controlling for effects of male age was also tested (old/satiated). Presence of female cues (S and SF) elicited much stronger gift construction response in males compared with the control group. Both groups of satiated males constructed nuptial gifts more frequently than starved males, spending more time on gift construction and using more silk. Our findings show that poor feeding condition affects pre-copulatory gift construction behaviour. Nuptial gift construction may be an honest indicator of male condition and therefore a target of female choice.