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Intraspecific Relationships and Nest Mound Shape Are Affected by Habitat Features in Introduced Populations of the Red Wood Ant Formica paralugubris. INSECTS 2022; 13:insects13020198. [PMID: 35206771 PMCID: PMC8875456 DOI: 10.3390/insects13020198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 02/03/2022] [Accepted: 02/10/2022] [Indexed: 02/05/2023]
Abstract
Simple Summary Red wood ants (Formica rufa goup) are dominant ant species widespread in the Eurasian continent. These species have a strong ecological impact on the habitats they dwell in, being top-ranked predators. One of the most striking features of these ants is represented by the large nest mounds they build. In this study, we investigated how nest mound shape and colony organization of imported populations of Formica paralugubris varied in three different habitat types. We found that nest mounds differed in size, number and shape in the three habitats. In all the three sites, nests were connected by trails of workers, but the size of these nest-networks differed. We also investigated the pattern of intraspecific aggression among ants from different nests, and we showed that aggressiveness was higher within each population than between separate populations, a finding in line with a ‘nasty neighbor’ behavior. Abstract Ants belonging to the Formica rufa group build large nest mounds, which aid their survival during severe winters. We investigated whether different environmental features of the habitats affected the nest mound shape and the population structure. We assessed the shape of all the nest mounds and mapped inter-nest trails connecting mounds for three imported populations of Formica paralugubris in three forest habitats: fir-dominated, beech-dominated, and a mixture of fir and beech. Single-nest mounds were averagely smaller and flatter in the beech-dominated forest, probably because of lighter building materials. Nonetheless, by summing the volumes of all interconnected nests, the size was similar among all three sites. In fir- and beech-dominated forests, large nests were also central in the networks, suggesting a central place foraging model with these nests as reference. We finally performed aggression tests, and found that aggressiveness was significantly higher among nests belonging to the same population than between populations. The results highlight the plasticity of the species to adapt nest and colony structure to different environments. Additionally, it appears that none of these populations is unicolonial, as observed in various alpine sites, there and the observed patterns of aggression are coherent with the ‘nasty neighbor’ effect.
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Lecheval V, Larson H, Burns DDR, Ellis S, Powell S, Donaldson-Matasci MC, Robinson EJH. From foraging trails to transport networks: how the quality-distance trade-off shapes network structure. Proc Biol Sci 2021; 288:20210430. [PMID: 33878925 PMCID: PMC8059596 DOI: 10.1098/rspb.2021.0430] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Biological systems are typically dependent on transportation networks for the efficient distribution of resources and information. Revealing the decentralized mechanisms underlying the generative process of these networks is key in our global understanding of their functions and is of interest to design, manage and improve human transport systems. Ants are a particularly interesting taxon to address these issues because some species build multi-sink multi-source transport networks analogous to human ones. Here, by combining empirical field data and modelling at several scales of description, we show that pre-existing mechanisms of recruitment with positive feedback involved in foraging can account for the structure of complex ant transport networks. Specifically, we find that emergent group-level properties of these empirical networks, such as robustness, efficiency and cost, can arise from models built on simple individual-level behaviour addressing a quality-distance trade-off by the means of pheromone trails. Our work represents a first step in developing a theory for the generation of effective multi-source multi-sink transport networks based on combining exploration and positive reinforcement of best sources.
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Affiliation(s)
| | - Hannah Larson
- Department of Biology, Harvey Mudd College, Claremont, CA, USA
| | | | - Samuel Ellis
- Centre for Research in Animal Behaviour, University of Exeter, UK
| | - Scott Powell
- Department of Biological Sciences, George Washington University, Washington, DC, USA
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Chang J, Powell S, Robinson EJH, Donaldson-Matasci MC. Nest choice in arboreal ants is an emergent consequence of network creation under spatial constraints. SWARM INTELLIGENCE 2021. [DOI: 10.1007/s11721-021-00187-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
AbstractBiological transportation networks must balance competing functional priorities. The self-organizing mechanisms used to generate such networks have inspired scalable algorithms to construct and maintain low-cost and efficient human-designed transport networks. The pheromone-based trail networks of ants have been especially valuable in this regard. Here, we use turtle ants as our focal system: In contrast to the ant species usually used as models for self-organized networks, these ants live in a spatially constrained arboreal environment where both nesting options and connecting pathways are limited. Thus, they must solve a distinct set of challenges which resemble those faced by human transport engineers constrained by existing infrastructure. Here, we ask how a turtle ant colony’s choice of which nests to include in a network may be influenced by their potential to create connections to other nests. In laboratory experiments with Cephalotes varians and Cephalotes texanus, we show that nest choice is influenced by spatial constraints, but in unexpected ways. Under one spatial configuration, colonies preferentially occupied more connected nest sites; however, under another spatial configuration, this preference disappeared. Comparing the results of these experiments to an agent-based model, we demonstrate that this apparently idiosyncratic relationship between nest connectivity and nest choice can emerge without nest preferences via a combination of self-reinforcing random movement along constrained pathways and density-dependent aggregation at nests. While this mechanism does not consistently lead to the de-novo construction of low-cost, efficient transport networks, it may be an effective way to expand a network, when coupled with processes of pruning and restructuring.
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Ecological Monitoring with Spy Satellite Images—The Case of Red Wood Ants in Romania. REMOTE SENSING 2021. [DOI: 10.3390/rs13030520] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Dynamics of habitat conditions drive important changes in distribution and abundance of animal species making monitoring an important but also a challenging task when data from the past are scarce. We compared the distribution of ant mounds in the 1960s with recent inventories (2018), looking at changes in canopy cover over time, in a managed forest. Both historical and recent sources of information were used. Habitat suitability at present was determined using a Normalized Difference Vegetation Index (NDVI) image as a proxy for stand canopy cover. The NDVI product was obtained using Google Earth Engine and Sentinel 2 repository. For past conditions (no spectral information available), presence of edges and more open canopies was assessed on a Corona spy-satellite image and based on information from old forest management plans. A threshold distance of 30 m was used to assess location of ant nests compared to favorable habitats. Both old and new information sources showed that ants prefer intermediate canopy cover conditions in their vicinity. Nests remained clustered because of the heterogeneous habitat conditions, but spatial distribution has changed due to canopy alteration along time. The analysis on the NDVI was effective for 82% of cases (i.e., nests occurred within 30 m from favorable habitats). For all the remaining nests (18%), the Google Earth high resolution satellite image revealed in their vicinity the presence of small canopy gaps (undetected by the NDVI). These results show that historical satellite images are very useful for explaining the long-term dynamics of ant colonies. In addition, the use of modern remote sensing techniques provides a reliable and expedite method in determining the presence of favorable small-scale habitat, offering a very useful tool for ecological monitoring across large landscapes and in very different areas, especially in the context of ecosystem dynamics driven and exacerbated by climate change.
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Consequences of Climate Change-Induced Habitat Conversions on Red Wood Ants in a Central European Mountain: A Case Study. Animals (Basel) 2020; 10:ani10091677. [PMID: 32957527 PMCID: PMC7552266 DOI: 10.3390/ani10091677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 09/11/2020] [Accepted: 09/15/2020] [Indexed: 11/21/2022] Open
Abstract
Simple Summary The red wood ants are considered to be one of the main ecosystem engineers and keystone species of the habitats in which they exist. Most of the species from this species group inhabit coniferous forests, which, due to the consequences of anthropogenic climate change, are continuously cut down. Therefore, the main habitat of these important species is rapidly disappearing. We investigated the consequences of the absence of conifers (clear-cut area and deciduous forest) on one of the members of this species group, namely Formica polyctena. We have found that compared with the mixed-coniferous forest stand, the absence of coniferous species resulted in significant changes in the colony and nest structure of F. polyctena. In addition, the colony size was also smaller in these sites. These changes suggest that although F. polyctena is able to survive in suboptimal habitats, still their population decline is expected and urges conservation managers to apply necessary action plans for their protection. Abstract The consequences of anthropogenic climate change are one of the major concerns of conservation biology. A cascade of negative effects is expected to affect various ecosystems, one of which is Central European coniferous forests and their unique biota. These coniferous forests are the primary habitat of many forest specialist species such as red wood ants. Climate change-induced rising of temperature allows trees to skip winter hibernation, making them more vulnerable to storms that cause wind felling, and in turn, promotes bark beetle infestations that results in unscheduled clear-cuttings. Red wood ants can also be exposed to such habitat changes. We investigated the effects of bark beetle-induced clear-cutting and the absence of coniferous trees on colonies of Formica polyctena, including a mixed-coniferous forest as a reference. Our aim was to investigate how these habitat features affect the nest characteristics and nesting habits of F. polyctena. Our results indicate that, in the absence of conifers, F. polyctena tend to use different alternatives for nest material, colony structure, and food sources. However, the vitality of F. polyctena colonies significantly decreased (smaller nest mound volumes). Our study highlights the ecological flexibility of this forest specialist and its potential to survive under extreme conditions.
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Juhász O, Bátori Z, Trigos-Peral G, Lőrinczi G, Módra G, Bóni I, Kiss PJ, Aguilon DJ, Tenyér A, Maák I. Large- and Small-Scale Environmental Factors Drive Distributions of Ant Mound Size Across a Latitudinal Gradient. INSECTS 2020; 11:insects11060350. [PMID: 32512838 PMCID: PMC7348728 DOI: 10.3390/insects11060350] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 05/30/2020] [Accepted: 06/01/2020] [Indexed: 11/16/2022]
Abstract
Red wood ants are keystone species of forest ecosystems in Europe. Environmental factors and habitat characteristics affect the size of their nest mounds, an important trait being in concordance with a colony’s well-being and impact on its surroundings. In this study, we investigated the effect of large-scale (latitude and altitude) and small-scale environmental factors (e.g., characteristics of the forest) on the size of nest mounds of Formica polyctena in Central Europe. We predicted that the change in nest size is in accordance with Bergmann’s rule that states that the body size of endotherm animals increases with the higher latitude and/or altitude. We found that the size of nests increased along the latitudinal gradient in accordance with Bergmann’s rule. The irradiation was the most important factor responsible for the changes in nest size, but temperature and local factors, like the perimeter of the trees and their distance from the nest, were also involved. Considering our results, we can better understand the long-term effects and consequences of the fast-changing environmental factors on this ecologically important group. This knowledge can contribute to the planning of forest management tactics in concordance with the assurance of the long-term survival of red wood ants.
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Affiliation(s)
- Orsolya Juhász
- Department of Ecology, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary; (Z.B.); (G.L.); (G.M.); (I.B.); (P.J.K.); (D.J.A.); (I.M.)
- Doctoral School in Biology, Faculty of Science and Informatics, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary
- Correspondence:
| | - Zoltán Bátori
- Department of Ecology, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary; (Z.B.); (G.L.); (G.M.); (I.B.); (P.J.K.); (D.J.A.); (I.M.)
| | - Gema Trigos-Peral
- Museum and Institute of Zoology, Polish Academy of Sciences, Wilcza Street 64, 00-679 Warsaw, Poland;
| | - Gábor Lőrinczi
- Department of Ecology, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary; (Z.B.); (G.L.); (G.M.); (I.B.); (P.J.K.); (D.J.A.); (I.M.)
| | - Gábor Módra
- Department of Ecology, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary; (Z.B.); (G.L.); (G.M.); (I.B.); (P.J.K.); (D.J.A.); (I.M.)
- Doctoral School of Environmental Sciences, University of Szeged, Rerrich Béla Square 1, H-6720 Szeged, Hungary
| | - Imola Bóni
- Department of Ecology, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary; (Z.B.); (G.L.); (G.M.); (I.B.); (P.J.K.); (D.J.A.); (I.M.)
| | - Péter János Kiss
- Department of Ecology, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary; (Z.B.); (G.L.); (G.M.); (I.B.); (P.J.K.); (D.J.A.); (I.M.)
- Doctoral School of Environmental Sciences, University of Szeged, Rerrich Béla Square 1, H-6720 Szeged, Hungary
| | - Dianne Joy Aguilon
- Department of Ecology, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary; (Z.B.); (G.L.); (G.M.); (I.B.); (P.J.K.); (D.J.A.); (I.M.)
- Doctoral School of Environmental Sciences, University of Szeged, Rerrich Béla Square 1, H-6720 Szeged, Hungary
- Department of Forest Biological Sciences, College of Forestry and Natural Resources, University of the Philippines Los Baños, Laguna 4031, Philippines
| | - Anna Tenyér
- Department of Physical Geography and Geoinformatics, University of Szeged, Egyetem Street 2-6, H-6722 Szeged, Hungary;
| | - István Maák
- Department of Ecology, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary; (Z.B.); (G.L.); (G.M.); (I.B.); (P.J.K.); (D.J.A.); (I.M.)
- Museum and Institute of Zoology, Polish Academy of Sciences, Wilcza Street 64, 00-679 Warsaw, Poland;
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Ellis S, Snyder-Mackler N, Ruiz-Lambides A, Platt ML, Brent LJN. Deconstructing sociality: the types of social connections that predict longevity in a group-living primate. Proc Biol Sci 2019; 286:20191991. [PMID: 31822256 PMCID: PMC6939919 DOI: 10.1098/rspb.2019.1991] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 11/14/2019] [Indexed: 12/16/2022] Open
Abstract
Many species use social interactions to cope with challenges in their environment and a growing number of studies show that individuals which are well-connected to their group have higher fitness than socially isolated individuals. However, there are many ways to be 'well-connected' and it is unclear which aspects of sociality drive fitness benefits. Being well-connected can be conceptualized in four main ways: individuals can be socially integrated by engaging in a high rate of social behaviour or having many partners; they can have strong and stable connections to favoured partners; they can indirectly connect to the broader group structure; or directly engage in a high rate of beneficial behaviours, such as grooming. In this study, we use survival models and long-term data in adult female rhesus macaques (Macaca mulatta) to compare the fitness outcomes of multiple measures of social connectedness. Females that maintained strong connections to favoured partners had the highest relative survival probability, as did females well-integrated owing to forming many weak connections. We found no survival benefits to being structurally well-connected or engaging in high rates of grooming. Being well-connected to favoured partners could provide fitness benefits by, for example, increasing the efficacy of coordinated or mutualistic behaviours.
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Affiliation(s)
- Samuel Ellis
- Centre for Research in Animal Behaviour, University of Exeter, Exeter, UK
| | | | - Angelina Ruiz-Lambides
- Caribbean Primate Research Center, University of Puerto Rico, San Juan, Puerto Rico, USA
| | - Michael L. Platt
- Department of Neuroscience, University of Philadelphia, Philadelphia, PA, USA
- Department of Psychology, University of Philadelphia, Philadelphia, PA, USA
- Department of Marketing, University of Philadelphia, Philadelphia, PA, USA
| | - Lauren J. N. Brent
- Centre for Research in Animal Behaviour, University of Exeter, Exeter, UK
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Pérez-Lachaud G, Klompen H, Poteaux C, Santamaría C, Armbrecht I, Beugnon G, Lachaud JP. Context dependent life-history shift in Macrodinychus sellnicki mites attacking a native ant host in Colombia. Sci Rep 2019; 9:8394. [PMID: 31182745 PMCID: PMC6557818 DOI: 10.1038/s41598-019-44791-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 05/22/2019] [Indexed: 11/21/2022] Open
Abstract
Ant parasitoidism has been reported in seven of the 26 recognized species of the mite genus Macrodinychus (Machrodynichidae). Macrodynichus sellnicki, previously reported as a parasitoid of the invasive ant Nylanderia fulva in Colombia, is now reported, in the same region, as attacking a native host, Ectatomma sp. 2 (E. ruidum complex). The mite develops within the protective silk cocoon of an Ectatomma pupa and waits for the emergence of the young ant before leaving the cocoon, unmolested. Overall nest prevalence was relatively high (34.6% of the 52 nests containing cocoons) but pupae prevalence was low (4.0%, n = 1401 cocoons). Mite life-history (parasite or parasitoid) was context dependent, shifting according to the intensity of the attack on a same host. Contrary to the strictly parasitoidic association of M. sellnicki with N. fulva, single mite attacks against E. ruidum did not result in host killing and solitary M. sellnicki (78.6% of the cases) behaved as parasites. However, in 21.4% of the attacks (0.9% of all available host pupae) more than one mite was involved and behaved as parasitoids, draining the host of its internal fluids and killing it. This is the first association of a macrodinychid mite with a species of the subfamily Ectatomminae, and the first ant associated mite for which such a context dependent life-style shift is described.
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Affiliation(s)
- Gabriela Pérez-Lachaud
- Departamento de Conservación de la Biodiversidad, El Colegio de la Frontera Sur, Chetumal, 77014, Quintana Roo, Mexico
| | - Hans Klompen
- Department of Evolution, Ecology and Organismal Biology, Ohio State University, Columbus, OH, 43212, USA
| | - Chantal Poteaux
- Laboratoire d'Éthologie Expérimentale et Comparée, EA 4443, Sorbonne Paris Cité, 93430, Villetaneuse, France
| | - Carlos Santamaría
- Departamento de Biología, Grupo GEAHNA, Universidad del Valle, Cali, Colombia
| | - Inge Armbrecht
- Departamento de Biología, Grupo GEAHNA, Universidad del Valle, Cali, Colombia
| | - Guy Beugnon
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, Université de Toulouse UPS, CNRS-UMR5169, UPS, 31062, Toulouse, Cedex 09, France
| | - Jean-Paul Lachaud
- Departamento de Conservación de la Biodiversidad, El Colegio de la Frontera Sur, Chetumal, 77014, Quintana Roo, Mexico.
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, Université de Toulouse UPS, CNRS-UMR5169, UPS, 31062, Toulouse, Cedex 09, France.
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9
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Ellis S, Franks DW, Nattrass S, Cant MA, Weiss MN, Giles D, Balcomb KC, Croft DP. Mortality risk and social network position in resident killer whales: sex differences and the importance of resource abundance. Proc Biol Sci 2018; 284:rspb.2017.1313. [PMID: 29070720 PMCID: PMC5666093 DOI: 10.1098/rspb.2017.1313] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 09/29/2017] [Indexed: 02/05/2023] Open
Abstract
An individual's ecological environment affects their mortality risk, which in turn has fundamental consequences for life-history evolution. In many species, social relationships are likely to be an important component of an individual's environment, and therefore their mortality risk. Here, we examine the relationship between social position and mortality risk in resident killer whales (Orcinus orca) using over three decades of social and demographic data. We find that the social position of male, but not female, killer whales in their social unit predicts their mortality risk. More socially integrated males have a significantly lower risk of mortality than socially peripheral males, particularly in years of low prey abundance, suggesting that social position mediates access to resources. Male killer whales are larger and require more resources than females, increasing their vulnerability to starvation in years of low salmon abundance. More socially integrated males are likely to have better access to social information and food-sharing opportunities which may enhance their survival in years of low salmon abundance. Our results show that observable variation in the social environment is linked to variation in mortality risk, and highlight how sex differences in social effects on survival may be linked to sex differences in life-history evolution.
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Affiliation(s)
- S Ellis
- Centre for Research in Animal Behaviour, University of Exeter, Exeter EX4 4QG, UK
| | - D W Franks
- Department of Biology, University of York, York YO10 5GE, UK
| | - S Nattrass
- Department of Biology, University of York, York YO10 5GE, UK
| | - M A Cant
- Centre for Ecology and Conservation, University of Exeter in Cornwall, Penryn, Cornwall TR10 9FE, UK
| | - M N Weiss
- Centre for Research in Animal Behaviour, University of Exeter, Exeter EX4 4QG, UK
| | - D Giles
- Center for Whale Research, 355 Smugglers Cove Road, Friday Harbor, WA 98250, USA
| | - K C Balcomb
- Center for Whale Research, 355 Smugglers Cove Road, Friday Harbor, WA 98250, USA
| | - D P Croft
- Centre for Research in Animal Behaviour, University of Exeter, Exeter EX4 4QG, UK
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Ellis S, Franks DW, Robinson EJH. Ecological consequences of colony structure in dynamic ant nest networks. Ecol Evol 2017; 7:1170-1180. [PMID: 28303187 PMCID: PMC5306006 DOI: 10.1002/ece3.2749] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 11/15/2016] [Accepted: 12/21/2016] [Indexed: 11/22/2022] Open
Abstract
Access to resources depends on an individual's position within the environment. This is particularly important to animals that invest heavily in nest construction, such as social insects. Many ant species have a polydomous nesting strategy: a single colony inhabits several spatially separated nests, often exchanging resources between the nests. Different nests in a polydomous colony potentially have differential access to resources, but the ecological consequences of this are unclear. In this study, we investigate how nest survival and budding in polydomous wood ant (Formica lugubris) colonies are affected by being part of a multi-nest system. Using field data and novel analytical approaches combining survival models with dynamic network analysis, we show that the survival and budding of nests within a polydomous colony are affected by their position in the nest network structure. Specifically, we find that the flow of resources through a nest, which is based on its position within the wider nest network, determines a nest's likelihood of surviving and of founding new nests. Our results highlight how apparently disparate entities in a biological system can be integrated into a functional ecological unit. We also demonstrate how position within a dynamic network structure can have important ecological consequences.
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Affiliation(s)
- Samuel Ellis
- Centre for Research in Animal BehaviourUniversity of ExeterExeterUK
| | - Daniel W. Franks
- York Centre for Complex Systems Analysis & Department of BiologyUniversity of YorkYorkUK
| | - Elva J. H. Robinson
- York Centre for Complex Systems Analysis & Department of BiologyUniversity of YorkYorkUK
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Procter DS, Cottrell JE, Watts K, A'Hara SW, Hofreiter M, Robinson EJH. Does cooperation mean kinship between spatially discrete ant nests? Ecol Evol 2016; 6:8846-8856. [PMID: 28035273 PMCID: PMC5192893 DOI: 10.1002/ece3.2590] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Revised: 10/04/2016] [Accepted: 10/06/2016] [Indexed: 11/26/2022] Open
Abstract
Eusociality is one of the most complex forms of social organization, characterized by cooperative and reproductive units termed colonies. Altruistic behavior of workers within colonies is explained by inclusive fitness, with indirect fitness benefits accrued by helping kin. Members of a social insect colony are expected to be more closely related to one another than they are to other conspecifics. In many social insects, the colony can extend to multiple socially connected but spatially separate nests (polydomy). Social connections, such as trails between nests, promote cooperation and resource exchange, and we predict that workers from socially connected nests will have higher internest relatedness than those from socially unconnected, and noncooperating, nests. We measure social connections, resource exchange, and internest genetic relatedness in the polydomous wood ant Formica lugubris to test whether (1) socially connected but spatially separate nests cooperate, and (2) high internest relatedness is the underlying driver of this cooperation. Our results show that socially connected nests exhibit movement of workers and resources, which suggests they do cooperate, whereas unconnected nests do not. However, we find no difference in internest genetic relatedness between socially connected and unconnected nest pairs, both show high kinship. Our results suggest that neighboring pairs of connected nests show a social and cooperative distinction, but no genetic distinction. We hypothesize that the loss of a social connection may initiate ecological divergence within colonies. Genetic divergence between neighboring nests may build up only later, as a consequence rather than a cause of colony separation.
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Affiliation(s)
- Duncan S. Procter
- York Centre for Complex Systems Analysis & Department of BiologyUniversity of YorkYorkUK
- Centre for Exercise, Nutrition and Health SciencesSchool for Policy StudiesUniversity of BristolBristolUK
| | | | | | | | - Michael Hofreiter
- Institut für Biochemie und BiologieUniversität PotsdamPotsdamGermany
| | - Elva J. H. Robinson
- York Centre for Complex Systems Analysis & Department of BiologyUniversity of YorkYorkUK
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