Misdirected courtship in a community of colorful jumping spiders

Dramatic and costly male courtship display is common in many animals.  In some cases, males engage in courtship indiscriminately, spending significant time and energy courting heterospecifics with whom they have no chance of mating or producing viable offspring.  Due to high costs and no clear benefits, we might expect mechanisms to evolve to reduce such misdirected courtship (or ‘reproductive interference’).  In Habronattus jumping spiders, males frequently court heterospecifics with whom they do not mate or hybridize; females are larger and are voracious predators, posing a severe risk to males who court indiscriminately.  In this study, we examine how misdirected courtship plays out in a natural community of four sympatric species of Habronattus (H. clypeatus, H. hallani, H. hirsutus, and H. pyrrithrix).  Using direct observations of spiders in the field, we weigh support for two potential hypotheses to explain how these species co-exist and how they reduce the costs associated with misdirected courtship.  Our first hypothesis is that heterospecific interaction rates are effectively reduced by differential use of the microhabitat (i.e., substrate, light environment) by the four different species.  Our second hypothesis is that these species are not segregated in the microhabitat, but rather, they interact frequently and must rely solely on communication with every individual that they encounter to identify appropriate mates and to mitigate the costs associated with misdirected courtship.  Our data show that, while the four species of Habronattus do show some differences in microhabitat use, all four species still overlap substantially.  As a result, for three of the four species, individuals were just as likely to encounter a heterospecific as they were to encounter a conspecific.  Males courted females at every opportunity, regardless of the species of the female.  In some cases, this heterospecific courtship led to aggression and predation by the female.  These results suggest that, while differences in microhabitat use might reduce misdirected courtship to some extent, co-existence of these four species is possible due to complex communication between both conspecifics and heterospecifics.  To our knowledge, this is the first study to examine misdirected courtship in a system where such behavior presents the severe risk of predation from the female being courted.  To date, studies of misdirected courtship and its consequences in the field are limited and may broaden our understanding of how biodiversity is maintained within a community.