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Facchini G, Rathery A, Douady S, Sillam-Dussès D, Perna A. Substrate evaporation drives collective construction in termites. eLife 2024; 12:RP86843. [PMID: 38597934 PMCID: PMC11006414 DOI: 10.7554/elife.86843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024] Open
Abstract
Termites build complex nests which are an impressive example of self-organization. We know that the coordinated actions involved in the construction of these nests by multiple individuals are primarily mediated by signals and cues embedded in the structure of the nest itself. However, to date there is still no scientific consensus about the nature of the stimuli that guide termite construction, and how they are sensed by termites. In order to address these questions, we studied the early building behavior of Coptotermes gestroi termites in artificial arenas, decorated with topographic cues to stimulate construction. Pellet collections were evenly distributed across the experimental setup, compatible with a collection mechanism that is not affected by local topography, but only by the distribution of termite occupancy (termites pick pellets at the positions where they are). Conversely, pellet depositions were concentrated at locations of high surface curvature and at the boundaries between different types of substrate. The single feature shared by all pellet deposition regions was that they correspond to local maxima in the evaporation flux. We can show analytically and we confirm experimentally that evaporation flux is directly proportional to the local curvature of nest surfaces. Taken together, our results indicate that surface curvature is sufficient to organize termite building activity and that termites likely sense curvature indirectly through substrate evaporation. Our findings reconcile the apparently discordant results of previous studies.
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Affiliation(s)
- Giulio Facchini
- Life Sciences Department, University of RoehamptonLondonUnited Kingdom
- Service de Chimie et Physique Non Linéaire, Université Libre de BruxellesBrusselsBelgium
- Laboratoire Matière et Systèmes Complexe, CNRS, Université Paris CitéParisFrance
| | - Alann Rathery
- Life Sciences Department, University of RoehamptonLondonUnited Kingdom
| | - Stéphane Douady
- Laboratoire Matière et Systèmes Complexe, CNRS, Université Paris CitéParisFrance
| | - David Sillam-Dussès
- Laboratoire d’Ethologie Expérimentale et Comparée, LEEC, UR 4443, Université Sorbonne Paris NordVilletaneuseFrance
| | - Andrea Perna
- Life Sciences Department, University of RoehamptonLondonUnited Kingdom
- Networks Unit, IMT School for Advanced Studies LuccaLuccaItaly
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Chiu CI, Chen BY, Chang FC, Kuan KC, Li HF. Functional Plasticity of Foraging Shelter Tubes Built by Termites. ENVIRONMENTAL ENTOMOLOGY 2022; 51:649-659. [PMID: 35861127 DOI: 10.1093/ee/nvac054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Indexed: 06/15/2023]
Abstract
Social insects' constructions are diverse and functionally flexible. We aimed to understand how termites modify their behavior and building material to change the function of a shelter tube. Construction behaviors of three termite species, Coptotermes formosanus Shiraki (Blattodea: Rhinotermitidae), Odontotermes formosanus (Shiraki) (Blattodea: Termitidae), and Nasutitermes takasagoensis (Nawa) (Blattodea: Termitidae), were recorded and analyzed. We measured the thickness and organic matter content of shelter tubes, and further tested their water loss and water drop resistance. All three termite species used a cement-brick construction procedure. The shelter tubes of C. formosanus and N. takasagoensis incorporating of woody material and feces present a strong resistance to water drops. Shelter tubes of the fungus-growing termite, O. formosanus, constructed using only soil and fluid secretion had a weak resistance to water drops. The trade-off between using feces to increase hydrophobicity of shelter tubes and using feces to grow fungus likely occurs in fungus-growing termites. Among intraspecific colonies, increasing the thickness of shelter tube improved resistance to water loss and water drops. This study demonstrated termites employed limited construction material and building behaviors to achieve functional plasticity of foraging shelter.
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Affiliation(s)
- Chun-I Chiu
- Department of Entomology, National Chung Hsing University, Taichung, Taiwan
- Department of Entomology and Plant Pathology, Faculty of Agriculture, Chiang Mai University, Muang District, Chiang Mai, Thailand
| | - Bo-Ye Chen
- Department of Entomology, National Chung Hsing University, Taichung, Taiwan
| | - Fang-Chih Chang
- The Experimental Forest, College of Bio-Resources and Agriculture, National Taiwan University, Zhushan Township, Nantou County, Taiwan
| | - Kuan-Chi Kuan
- Department of Entomology, National Chung Hsing University, Taichung, Taiwan
- Department of Applied Economics, National Chung Hsing University, Taichung, Taiwan
| | - Hou-Feng Li
- Department of Entomology, National Chung Hsing University, Taichung, Taiwan
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Kanyi NC, Karuri H, Nyasani JO, Mwangi B. Land use effects on termite assemblages in Kenya. Heliyon 2021; 7:e08588. [PMID: 34977409 PMCID: PMC8683729 DOI: 10.1016/j.heliyon.2021.e08588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 10/08/2021] [Accepted: 12/08/2021] [Indexed: 11/17/2022] Open
Abstract
Termites perform key ecological functions and they also cause crop damage. Land use change resulting from agricultural intensification can result in changes in termite species diversity and abundance. Termite species occurring in natural vegetation, maize monocrop and maize-beans intercrop macrohabitats were investigated in Embu and Machakos Counties, Kenya. Influence of soil properties and seasons was also evaluated. Across the two Counties, seven termite species were recorded with Machakos County having the highest number. Additive diversity partitioning of species richness and Simpson diversity showed that, α component contributed to 98.3% and 99.1% of the total diversity, respectively. Population densities of three termite species significantly varied between land use types in Machakos County but there were no differences in termite species abundance in Embu County. In addition, there were no significant differences in species richness between macrohabitats within each County. In Embu, season significantly influenced the abundance of Macrotermes subhyalinus, M. herus, and Coptotermes formosanus which occurred in greater numbers during the wet season. There was a significant influence of land use on Trinervitermes gratiosus and C. formosanus in Machakos with both species occurring in higher numbers in natural vegetation. Trinervitermes gratiosus was negatively associated with Mn and positively correlated to pH and sand. Macrotermes subhyalinus and M. herus showed a positive association with P and silt while C. formosanus was positively correlated to Ca and Mg. These findings provide an insight into the effects of land use change from natural vegetation to maize agro-ecosystems on termite diversity. It also provides a baseline for further studies on termite diversity in Kenya and their ecological significance.
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Wildermuth B, Oldeland J, Juergens N. A beneficial relationship: associated trees facilitate termite colonies (
Macrotermes michaelseni
) in Namibia. Ecosphere 2021. [DOI: 10.1002/ecs2.3671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- B. Wildermuth
- Institute of Plant Sciences and Microbiology University of Hamburg Hamburg Germany
| | - J. Oldeland
- Institute of Plant Sciences and Microbiology University of Hamburg Hamburg Germany
| | - N. Juergens
- Institute of Plant Sciences and Microbiology University of Hamburg Hamburg Germany
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The role of mound functions and local environment in the diversity of termite mound structures. J Theor Biol 2021; 527:110823. [PMID: 34217730 DOI: 10.1016/j.jtbi.2021.110823] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 05/26/2021] [Accepted: 06/27/2021] [Indexed: 11/23/2022]
Abstract
Mound structures that soil termites build have diverse morphologies. Previous observational studies documented that mounds are built to provide regulated environments for the termites that live within them and their structures are formed in ways to support this purpose under the influence of the mounds' immediate environment. The objective of this study is to provide a methodology and a predictive computational model to investigate the reason behind the different but systematic shapes of termite mounds, considering all the relevant forces imposed on them and their thermoregulatory and gas-exchange functions. The gas-exchange function accounts for the capacity of the mound to diffuse metabolic gases generated in the mound's underground nest, while the thermoregulatory function satisfies the connection between the underground nest and deep ground temperatures. The proposed predictive model is based on the principles of heat transfer and thermodynamics and allows optimized mechanically stable structures to freely emerge. The results indicate that, while the model is free to generate any mechanically stable structure, under the relevant environmental and metabolic conditions, it produces structures with forms and geometrical characteristics similar to those of natural mounds. Investigation of the connection between the local environment and the mound shapes indicated that the Sun and wind play an important role in the mound structural form. Mounds exposed to stronger solar irradiance exhibit cone-shaped structures that are pointed towards the Sun, while shaded mounds are observed to be vertical domes. The local wind is observed to affect the external shape of the mound by preventing them to grow tall while controlling the features of the internal structure. By investigating the similarities between structures in different regions (i.e., India, Namibia, and Brazil), it is revealed that, unlike mounds with a strong need for gas-exchange, mounds with a significant demand for thermoregulation exhibit deeper nests, thicker external walls, and well-defined cone- (as opposed to the dome-) shaped structures. Overall, the form of termite mounds is strongly correlated to both regulatory functions and local environments, and the resulting mound shape arises as a combination of these factors.
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Jolles JW. Broad‐scale applications of the Raspberry Pi: A review and guide for biologists. Methods Ecol Evol 2021. [DOI: 10.1111/2041-210x.13652] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Jolle W. Jolles
- Zukunftskolleg University of Konstanz Konstanz Germany
- Department of Collective Behaviour Max Planck Institute of Animal Behaviour Konstanz Germany
- Centre for Research on Ecology and Forestry Applications (CREAF) Barcelona Spain
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Carey NE, Bardunias P, Nagpal R, Werfel J. Validating a Termite-Inspired Construction Coordination Mechanism Using an Autonomous Robot. Front Robot AI 2021; 8:645728. [PMID: 33969004 PMCID: PMC8098689 DOI: 10.3389/frobt.2021.645728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 03/19/2021] [Indexed: 11/13/2022] Open
Abstract
Many species of termites build large, structurally complex mounds, and the mechanisms behind this coordinated construction have been a longstanding topic of investigation. Recent work has suggested that humidity may play a key role in the mound expansion of savannah-dwelling Macrotermes species: termites preferentially deposit soil on the mound surface at the boundary of the high-humidity region characteristic of the mound interior, implying a coordination mechanism through environmental feedback where addition of wet soil influences the humidity profile and vice versa. Here we test this potential mechanism physically using a robotic system. Local humidity measurements provide a cue for material deposition. As the analogue of the termite's deposition of wet soil and corresponding local increase in humidity, the robot drips water onto an absorbent substrate as it moves. Results show that the robot extends a semi-enclosed area outward when air is undisturbed, but closes it off when air is disturbed by an external fan, consistent with termite building activity in still vs. windy conditions. This result demonstrates an example of adaptive construction patterns arising from the proposed coordination mechanism, and supports the hypothesis that such a mechanism operates in termites.
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Affiliation(s)
- Nicole E Carey
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, United States.,Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, United States
| | - Paul Bardunias
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, United States.,Department of Civil and Environmental Engineering, South Dakota School of Mines, Rapid City, SD, United States
| | - Radhika Nagpal
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, United States.,Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, United States
| | - Justin Werfel
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, United States.,Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, United States
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Bardunias PM, Calovi DS, Carey N, Soar R, Turner JS, Nagpal R, Werfel J. The extension of internal humidity levels beyond the soil surface facilitates mound expansion in Macrotermes. Proc Biol Sci 2020; 287:20200894. [PMID: 32635873 DOI: 10.1098/rspb.2020.0894] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Termites in the genus Macrotermes construct large-scale soil mounds above their nests. The classic explanation for how termites coordinate their labour to build the mound, based on a putative cement pheromone, has recently been called into question. Here, we present evidence for an alternate interpretation based on sensing humidity. The high humidity characteristic of the mound's internal environment extends a short distance into the low-humidity external world, in a 'bubble' that can be disrupted by external factors like wind. Termites transport more soil mass into on-mound reservoirs when shielded from water loss through evaporation, and into experimental arenas when relative humidity is held at a high value. These results suggest that the interface between internal and external conditions may serve as a template for mound expansion, with workers moving freely within a zone of high humidity and depositing soil at its edge. Such deposition of additional moist soil will increase local humidity, in a feedback loop allowing the 'interior' zone to progress further outward and lead to mound expansion.
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Affiliation(s)
- Paul M Bardunias
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA.,Department of Civil and Environmental Engineering, South Dakota School of Mines, Rapid City, SD 57701, USA
| | - Daniel S Calovi
- Harvard School of Engineering and Applied Sciences, 33 Oxford Street, Cambridge, MA 02138, USA
| | - Nicole Carey
- Harvard School of Engineering and Applied Sciences, 33 Oxford Street, Cambridge, MA 02138, USA
| | - Rupert Soar
- School of Architecture, Design and the Built Environment, Nottingham Trent University, Burton Street, Nottingham, UK
| | - J Scott Turner
- Department of Environmental and Forest Biology, SUNY College of Environmental Science and Forestry, Syracuse, NY 13210, USA
| | - Radhika Nagpal
- Harvard School of Engineering and Applied Sciences, 33 Oxford Street, Cambridge, MA 02138, USA.,Wyss Institute for Biologically Inspired Engineering, Harvard University, 60 Oxford Street, Cambridge, MA 02138, USA
| | - Justin Werfel
- Wyss Institute for Biologically Inspired Engineering, Harvard University, 60 Oxford Street, Cambridge, MA 02138, USA
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