Habitat use is shaped by pressures including the need to avoid predation and the need to successfully reproduce, which often requires communication with conspecifics. Jumping spider males of several species use simultaneous visual and vibrational signals when courting females. These vibrations travel via substrate, not air, and so substrate choice can affect signal intensity. Jumping spiders also actively hunt and stalk prey, rather than using the sit-and-wait predation strategy of web-building spiders. This in turn means that foraging jumping spiders are exposed to any predators in the area.
To test for effects of predation pressure and signaling efficiency on habitat choice, we surveyed density of active Menemerus bivittatus individuals and a common predator, Anolis lizards, on oaks, palms, and concrete to determine habitat use. We also measured the relative ability of each substrate to transmit the frequencies used in M. bivittatus courtship signaling.
Results/Conclusions
M. bivittatus is rarely found on either tree trunk type, but is common on concrete pillars. This is likely the result of predation, as several Anolis lizard species are abundant on the tree trunks but rare on the pillars. While this could mean spiders are forced into a sub-optimal signaling environment, we instead found that concrete is a very efficient signaling substrate for this jumping spider species, suggesting there is no signaling cost to being forced from tree trunks, a known habitat for this species in other parts of their range.