I am not a plant person. It doesn’t mean that I don’t like plants, or that I don’t find them interesting, but just that I don’t know enough about their properties, their physiology or their specific role in an ecosystem. Consequently, the first days at Barro Colorado Island (BCI) were quite challenging and really interesting for me because we talked a lot about the specificity of the tropical forests, with the central question being about the enormous diversity of plants that compose it. The different explanations of this diversity highlight for example the importance of plant-herbivore interactions or microbial soil composition.
What struck me the most while listening to the STRI researchers is that one could expect a huge variety of food source for the herbivores that live in those forests. It is true for the invertebrates, but when you look at the vertebrates, at this time of the year, there’s only one species of tree providing fruits to all the frugivores. This tree is the Dipteryx, and you can easily spot its seeds that are chewed by the monkeys and that are approximately the size of a flat kiwi.
Some species are feeding on other parts of plants, like the howler monkey Alouatta palliata that is eating young leaves, but species like the capuchin Cebus capucinus of BCI rely almost entirely on the fruit of this tree for food in the dry season. Dr Meg Crofoot was explaning to us this morning that two years ago, the capuchin monkeys experienced high mortality due to a late fruiting period of Dipteryx. Considering the big el niño event this year, and especially the following big wet season next year that should also delay the fructification, let’s hope for the capuchin monkeys to find some other source of food!