I have for a long time been fascinated by the symbiotic relationship between some species of acacias and ants. Honestly, I have also for a long time been fascinated by ants alone. Now some researchers have observed interesting behavior by a species of jumping spider, Bagheera kiplingi, that lives on the same acacia plants.
In many of these ant-plant relationships, the ants are provided food -— called Beltian bodies -— by the acacia plant. The researchers observed the spider B. kiplingi “hunting” and eating the Beltian bodies as its primary source of food, making this spider the first known to have a primarily vegetarian diet.
Read a summary of the research here. The research manuscript is at doi:10.1016/j.cub.2009.08.049, but you will need an individual or institutional subscription to get the full text.