We know that Azteca ant colonies gallantly defend their nourishing Cecropia home-trees from leaf-eaters and choking vines. However, it turns out that some colonies defend more gallantly than others in a suite of behavioral traits measured in the field, revealing that colonies themselves have personalities. Trees that have more active, aggressive colonies have less leaf damage, suggesting that colony personality plays an important role in this intimate mutualism.
Read the paper here.
Cecropia seeds lay dormant on the rainforest floor, sometimes for years, awaiting a break in the canopy to spurt a ray of light. The seed senses the changing environment and germinates with explosive growth. Soon after, a new Azteca queen will colonize the plant, found a colony, and help protect it from other gap-growing competitors.
The Entomological Society of America holds a wonderful YouTube contest at their annual conference. For this year's contest, I submitted the video that Andrew Quitmeyer and I made about the general magic that is the Azteca-Cecropia mutualism - and we received first place! I give most of the credit to the level 10 charisma of the system and the amazing Quitmeyer. Watch the other superb video finalists here.
As a form of creative expression, experiencing my data in a different way, and relaying my scientific narrative with the public and other scientists, I have created the Forest of the Glowing Symbionts. These glowing tree sculptures represent specific Cecropia trees and their Azteca colonies from my collective personality field experiment. The timing of the blinking in each scaled tree is synced with real ant patrolling data from different colonies. When shaken, the lights ignite just as the colony did, with a data-based spurt of increased activity. By observing the trees' blinking patterns and how they respond to vibration, you can get a sense of the colonies' personality.
The best way to see a sloth in the tropics is to scan large Cecropia trees, looking for a still, amorphous lump. The common knowledge is that they spend most of their time in Cecropia trees, preferring their leaves. But do they? It may be just a simple observation bias given that the minimal, elegant structure of the tree provides the best chance to spot something that doesn't fit. Either way, what I'm really interested in is their interaction with Azteca ants. Do ants somehow ignore these slow moving beasts? Or do the sloths ignore the potential onslaught? Or perhaps colonies differ in their response to sloths. I've gathered minimal anecdotal evidence for any of these ideas because it's hard to get up close to observe whats happening. I have seen sloths get deterred from a tree before they even reach the leaves, and I've seen sloths eating at their leisure. Perhaps it is the sloths that vary in boldness or pain tolerance. Experiment planning is underway.
These howler monkeys have very different foraging approaches depending on which Cecropia tree they are feeding on. In the first shot, the monkey seems to be minimizing its contact with the plant by reaching out from a another tree, retreats quickly after snapping off the soft meristem, and presumably scratches off the attacking Azteca ants. In the second shot, the monkey is chomping at its leisure, lounging on the Cecropia tree itself. Perhaps these monkeys are being met with differing levels of aggression by the resident Azteca guardians . . .
So far, I've been focusing on medium-aged colonies in medium-sized tree for standardization reasons. In a recent experiment conducted with Karla Moeller, we expanded our sampling to include young saplings and old giants. Here's a sneak peak at how one of our sapling colonies responded to leaf damage. Note that as the ant that discovered the damage returns to the stem to rally her nestmates, she is dragging her abdomen, laying a guiding chemical trail.
All in all, there were 31,054 ants from 17 colonies in the greenhouse by the end of the study. At least 22,554 were born there. More specific stats forthcoming.