The first, tantalizing signs of something special!

 

Ignoring the multiple ant stings on my finger, I want to direct your attention to the vials sitting on the laboratory bench behind. These were primarily samples that I collected in Palo Verde, Costa Rica, both Bagheera spiders and Pseudomyrmex ants. A few non-Bagheera (and probably carnivorous) jumping spiders were included for comparison. In this case, my goal is to search for symbiotic bacteria that might allow Bagheera to thrive on its 90% vegetarian diet, a shift that is rare in the animal world.

In fact, I can only think of one group of animals that even comes close to this sort of dietary diversity: bears.

 

Of course, this comparison isn't perfect, since most bears (excluding the polar bear) subsist on diets that are comprised of more than half plant material. The black bear, in fact, is 85% vegetarian, and the brown bear (a.k.a. the grizzly bear in North America) is up to 90% vegetarian (sound familiar?). This is in stark contrast to its close relative, the polar bear, which is almost entirely carnivorous, and the giant panda (which is, in fact, a bear) at 99% vegetarian.

Recent research has shown that the panda uses symbiotic bacteria to process its plant-based diet, and brown bears use bacteria in their gut to help process nitrogen. Since animal proteins and other meat components are generally easier to process than plant material, polar bears don't necessarily need to benefit from such associations. Considering that most spiders are also 100% carnivorous, it seems unlikely that they would need the help of bacteria to digest their food.

Which leads me to the exciting news--one of my collaborators might have found symbiotic bacteria in a sample of Bagheera! Even more astounding is that these bacteria are similar (or identical) to the symbiotic bacteria already found in Pseudomyrmex ants! All the more reason for this research to continue--and for more samples to be collected in coming months.