![]() ![]() In parallel, some orangutans have been observed to occasionally add to their nest, branches from a different species having mosquito-repellent activity 11. A more recent study in the Sebitoli community 10, shows that essential oils from leaves of seven out of ten tree species commonly used by chimpanzees for nesting possess spatial repellent activity against Anopheles gambiae, an African mosquito, vector of Plasmodium falciparum, a parasite responsible of malaria. On the other hand, in the Toro-Semliki Wildlife Reserve in Uganda, individuals are shown to choose one specific tree species that experimentally deters flying arthropods in the field 9. These studies did not examine the possible influence of the tree species itself. In addition, a preliminary study in Kibale National Park in Uganda has shown that chimpanzees chose sites for nesting in altitude and at a height in trees where mosquitoes are less abundant 7, unlike the results obtained in Nimba Mountain in Guinea where no correlation was found between height of nests and mosquito abundance 8. One explanation, inspired by “the pathogen avoidance hypothesis”, is that individuals may prefer trees that release aromatic substances to mask their odor or repel annoying insects that may be vectors of parasites 6. Yet, increasing the time spent in active sleep could lead to better memory consolidation 4, which could be one of the crucial steps in the evolution of hominids and their mental and manipulative abilities 5. Identifying the determinants of tree species choice could help us understand how chimpanzees improve sleep quality in their nest. This behavior has raised questions about the drivers of this tree species selectivity. Interestingly, some chimpanzee and orangutan communities studied appear to choose particular tree species to build their nests 1, 3. Weaned individuals bend, break and intertwine leafy branches and twigs to form a circular platform or bowl-shaped structure 2. Finally, a comparison across chimpanzee communities would be relevant to understand whether these choices are not only ecological but also cultural.Įvery evening, great apes build sleeping platforms commonly called ‘nests’ usually in trees in which they spend the night 1. These tree properties may provide a comfortable sleeping environment enhancing sleep quality. In addition, most tree species with such mechanical and morphological properties also have mosquito repellent activity. Chimpanzees chose tree species with medium-sized and elongated foliar units, high foliar density and branch with stiffer wood. Their spatial repellent activity, previously tested against Anopheles gambiae was incorporated into the analysis. ![]() For these 20 tree species, we determined their biomechanical and morphological characteristics such as foliar density, foliar units form (shape and size) and branch rigidity. ![]() The ten tree species most frequently used for nesting were compared with ten abundant in their environment but not preferred for nesting. We investigate these hypotheses, or a trade-off between both, though study of tree species preference based on their biomechanical and/or biochemical properties in the Sebitoli chimpanzee community in Kibale National Park, Uganda. In some studied communities, individuals appear to be selective about the tree species used, which has led researchers to hypothesize whether chimpanzees prefer trees that repel troublesome insects or/and that provide comfortable and stable structures. Every evening, chimpanzees build sleeping “nests” in trees. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |