Jumping spiders in space: movement patterns, nest site fidelity and the use of beacons

We studied movement patterns and the use of navigational beacons in the jumping spider Phidippus clarus (Salticidae). Phidippus clarus does not build prey-capture webs, but does construct thick silken nests used as nighttime retreats. We measured the degree of nest site fidelity with individually marked spiders and a grid of artificial nest tubes. Females in August were most site-faithful, followed by July females and then by males. Spiders moved long distances through complexly structured habitats, suggesting that nests are likely to be out of sight of the spiders during the day, and that spiders must use cues other than their nest to navigate. We then tested whether females used beacons to find their nests. In one experiment, spiders colonized nest tubes that were either associated with beacons (orange wooden dowels) or not. They were then released near a test beacon. Spiders experienced with beacons readily approached either their own beacon or a similar, novel beacon in a different location. In contrast, spiders with no experience with beacons were significantly less likely to approach the test beacon. In a second test, spiders tested with novel beacons of the same colour as their own were significantly more likely to approach it than were spiders tested with novel beacons of a different colour. We conclude that P. clarus are likely to need navigational skills and are able to use beacons as a method of navigation. Jumping spiders provide a new and tractable model system for the study of navigation and space use.