The architectural design of smart ventilation and drainage systems in termite nests

Singh, Kamaljit; Muljadi, Bagus P; Raeini, Ali Q; Jost, Christian; Vandeginste, Veerle; Blunt, Martin J; Theraulaz, Guy; Degond, Pierre; Singh, Kamaljit

Abstract

Termite nests have been widely studied as effective examples for ventilation and thermoregulation; however, the mechanisms by which the nest properties are controlled by the micro-structure of the outer walls remain unclear. Here, we combine multi-scale X-ray imaging with three-dimensional flow field simulations to investigate the impact of the architectural design of nest walls on CO2 and heat transport as well as on water drainage. We show that termites construct an outer wall that contains both small and percolating large pores at the micro-scale. The network of larger micro-scale pores in the outer wall provides a permeability that is 1-2 orders of magnitude greater than that of the smaller pores, and a CO2 diffusivity that is a factor of up to eight times larger. The larger pores and resultant high porosity also reduce the solid mass required for nest construction by ~11-14%. This is energetically favorable and reduces the overall weight of the nest, thus lowering the risk of collapse. In addition, the pore network offers enhanced thermal insulation to the inner parts of the nest and allows quick drainage of rainwater thereby restoring the ventilation and providing structural stability to the wet nest. One Sentence Summary: Ventilation and drainage in termite nests are controlled by micro-scale morphological features of the outer walls.

Citation

Singh, K., Muljadi, B. P., Raeini, A. Q., Jost, C., Vandeginste, V., Blunt, M. J., Theraulaz, G., Degond, P., & Singh, K. (2019). The architectural design of smart ventilation and drainage systems in termite nests. Science Advances, 5(3), Article eaat8520. https://doi.org/10.1126/sciadv.aat8520

• Journal Article Type: Article
• Acceptance Date: Jan 7, 2019
• Online Publication Date: Mar 22, 2019
• Publication Date: Mar 1, 2019
• Deposit Date: Jul 17, 2020
• Publicly Available Date: Jul 17, 2020
• Electronic ISSN: 2375-2548
• Publisher: American Association for the Advancement of Science
• Peer Reviewed: Peer Reviewed
• Volume: 5
• Issue: 3
• Article Number: eaat8520
• DOI: https://doi.org/10.1126/sciadv.aat8520
• Public URL: https://nottingham-repository.worktribe.com/output/1626393
• Publisher URL: https://advances.sciencemag.org/content/5/3/eaat8520