In a recent poll of BCI frugivores 13 out of 15 species agreed – Attalea palm fruit restaurants are much better than Astrocaryum palms. The two hold outs, rodents agouti and spiny-rat, both prefer the uncrowded atmosphere at Astrocaryums, but are also known to grab a bite at Attalea’s when they’re in the neighborhood.
The results of this surprising poll were recently presented by Vivian Maas as she defended her MSc degree in Forest and Nature Conservation at Wageningen University. Vivian took the poll by using camera traps to record the frequency and behavior of animal visitors to fruiting palms of two species: Astrocaryum standleyanum and Attalea butyracea. These have long been considered keystone restaurants for the mammal community on Barro Colorado Island. Although researchers frequently see animals loitering around these establishments, there had been no systematic poll of their opinion of these two restaurant chains.
“I just love chomping Attalea fruits”, said one macho tapir, “their flavor puts me at ease and lets my mind wander to happy times”. A coati matriarch agreed, “The open understory under their big fronds is a perfect place to let my kids play while I catch a bite to eat. Under an Astrocaryum I’m constantly worried they’ll put there eye out on a spine.”
For each mammal species, Vivian calculated how often they visited the trees, how much time they spent at the trees, and was even able to tell how many fruits they took by watching the videos. She also compared the animal activity under palms with that of random sites. In total, both restaurant chains attracted nearly 10x more animal visitors than a typical random place on BCI. Agoutis and squirrels were the primary patrons of Astrocaryum, while Attalea was also popular with coatis, tapirs, peccaries, opossums, and other species.
However, not all species like the Palm restaurants, Brocket deer seemed to avoid the trees, and when they did wander by, didn’t eat any fruits. “I don’t need to fight through the crowds only to break my teeth on this sugary fast-food” commented one Brocket deer, “they don’t even have a salad bar!” Pacas, another fruit eating mammal, also visited the fruiting palms less than expected given their overall abundance on BCI.
A primary hypothesis of the study was to test if the mammal community varied with the abundance of the palms: do isolated restaurants attract a different suite of animals than those clusters? Do palm restaurants get the most business by follow the Starbuck’s strategy of one on every corner? To find out, Vivian choose palms ranging from isolated to clustered individuals and used multivariate statistics to determine how community composition varied with palm abundance. She found that agoutis were more dominant visitors as the palms were more isolated in Attalea, while in Astrocaryum, the reverse was true.
Spokespersons for both restaurant chains had no comment, because they are plants, and can not talk.