The University of Amsterdam wrote a short article about my work in Xishuangbanna Tropical Botanical Garden (XTBG) in Yunnan, China. Unfortunately it’s in Dutch, but I’ll give a short summary here.
In July and August I spent three weeks at XTBG and Kunming Institute of Botany to investigate the colour of palm fruits. XTBG is home to > 300 species of palms, and these show a high interspecific variation in fruit colour, ranging from black to purple to yellow, orange and red. Why does this variation in fruit colour exist? I hypothesise that fruit colour may be adaptive to frugivory – that is, fruit-eating and seed dispersal by animals.
Certain primates are ‘trichromatic’, which means that they can distinguish between red and green (such as humans) whereas other species of primates are dichromatic and can’t distinguish green from red (such as colourblind humans). These trichromatic primates can therefore easily detect reddish fruits against a background of greenish leaves in the rain forest, thereby having an advantage over dichromatic primates – which may have more difficulties finding food under these conditions. To test the hypothesis, I therefore expect that in areas where there is a dominance of trichromatic primates (such as chimpansees, gorillas and howler monkeys), palms with reddish fruits are also more common, as compared to areas dominated by dichromatic primates.
At XTBG I analysed the colour of palm fruits using a constant light source and software to quantify these colours (rather than a subjective classification of ‘green’, ‘red’ or ‘orange’). Together with my collaborators at the University of Amsterdam (my master student Daphne Vink, bachelor student Jorin Veen and Dr. Daniel Kissling) I aim to spend the coming months on analysing these data in a biogeographical context, using distribution and fruit colour data of > 2000 species of palms.
This research is important to better understand why fruits display such a wide range of colours – and to be able to predict how ongoing extinctions of primates may affect the future evolution of colours in the rain forest.
Besides sampling palms, I also presented my previous work at XTBG and Kunming, and had exciting discussions on ongoing work and future collaborations with the members of the Ecology and Biogeography group, led by Prof. Yaowu Xing.