Male mate choice in a gift giving spider: do males adjust their sexual investment according to females' body condition?

Abstract

Male mate choice occurs when sexual investment by males in either mating of parental effort is very high. Among gift giving species, it is expected that males would be choosy during mate selection because the gift is costly to produce. In this research, we tested whether males of the gift giving spider Paratrechalea ornata adjust their reproductive investment (i.e., gift size, courtship intensity, and quantity of sperm transferred to the female) according to females' body condition. According to the positive differential allocation hypothesis, males are expected to invest more in females in good body condition. In turn, according to the negative differential allocation hypothesis, males are expected to invest more in females with poor body condition. We will test these concurrent hypotheses using a laboratory experiment in which we will manipulate females' body condition and record males' responses. From a general perspective, this research will be an empirical test on the generality of the differential allocation hypotheses, which are concentrated exclusively on vertebrates. Furthermore, the research will provide new information on male mate choice in a gift giving species. (AU)