For the jumping spider, it pays to live in a dangerous neighborhood. Researchers have discovered that wild Philippine jumping spiders (Phintella piantensis) erect their web-spun homes directly above nests of spider-eating weaver ants. Because weaver ants (Oecophylla smaragdina) enjoy snacking on jumping spiders, as seen in the above photo, the team wondered why the spiders would move in so close to their natural enemy. The scientists speculated that the ants serve as the jumping spider's home security against the spitting spider, another one of its predators. The spitting spiders (Scytodes) typically steer clear of weaver ants’ nests to avoid being swarmed and eaten. To test how the two spider species react to the presence of weaver ants, the team built transparent boxes complete with green-painted cardboard leaves. Spiders were placed in the boxes one at a time and presented with either live ants behind a transparent panel, ant scents, or no ant cues at all. In tests where ants were smelled or seen, jumping spiders built far more web nests while spitting spiders built substantially fewer, the researchers report this week in Behavioral Ecology and Sociobiology. The team believes the jumping spider's tightly woven nest, complete with protective door flaps, guards the spider from ant assaults while the spitting spider’s loosely constructed nest leaves it open for attack. Because the ants don't benefit from the close proximity of jumping spiders, it seems like the jumping spider gets its protection with no strings attached.

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