Cephalotes pusillus soldier and worker. Image cc Jon Sanders.
Today was my first real attempted collecting day -- Scott graciously drove me out to Panga (the preserve) to poke around looking for Cephalotes. Unfortunately, it was cool, drizzling, and overcast, during which time most Cephalotes would apparently rather just stay indoors. So we didn't rack up a huge species count.
But there were ants! Tons of ants! Camponotus, Azteca, Tetraponera, Pachycondyla, Dorymyrmex, and even some Cephalotes, despite the weather. Pachycondyla marginata is particularly cool, an insanely shiny and dangerous-looking Ponerine (viz. 'badass') that makes a living raiding termite mounds, carrying away their children, and eating them. A quick Google suggests that they may also have magnetite-based internal compasses, the better to find you with, my dearies.
Most of what recruited to our baits were Azteca, Dorymyrmex, and Cephalotes pusillus (pictured). C. pusillus is apparently one of the more common and widespread Ceph. species, and was certainly abundant today -- hundreds were swarming out of their nests, facilitating a nice starter collection for me to practice on. Randomly snapping dead twigs also netted us a few C. maculatus and C. grandinosus, both of which look pretty radically different from pusillus and which I'm excited to get under the microscope.
Like many ant species, C. pusillus shows some fairly apparent worker polymorphism, with some of the sterile, wingless, female workers belonging to larger 'soldier' castes, and others to smaller 'worker' castes. The photo above, which is just about the best of my sorry first attempts at macro photography, serves as a fairly good illustration. In many Cephalotes species (not pusillus), the soldiers have specially developed, door-like disks on the front of their heads, which are used to plug the nest entrance in defense against attack by other insects and the like (they're not very effective against twig-snapping entomologists). The evolution of this polymorphism, and its effect on the diversification and ecology of the genus, form a big chunk of Dr. Scott Powell's ongoing research program.
Tomorrow, we're back in the field collecting from yesterday's pitfall traps. Never have I been so excited about spending a day poking through insects floating in cups of two-day-old piss. I'll keep you posted.