14/10: Ecology of social insects14/10 - Ecology of social insects
ORGANIZERS: Xim Cerda a, Ioan Tausan b a Estación Biológica Doñana, CSIC, Spain; b Lucian Blaga University of Sibiu, Romania
CONTACT: xim@edb.csic.es
SUMMARY: The ecology of social insect communities is a very classical research subject, but one that keeps moving forward. As an example, competitive dominance hierarchies have been a paradigm in ant ecology for decades, but recently their utility, if not existence, has been questioned. What, if anything, is the importance of competition in social insect communities? How does the structure of social insect communities vary in space and time, at what scales, and what contributes to that variation? More studies, at both local and global scales, of social insect communities are needed to elucidate the complex interactions that modulate community structure in different biogeographic regions, with the ultimate goal being to understand processes and patterns, and thus build a solid theory of social insect community ecology. In this symposium we will include both classical (e.g. spatial and temporal structure), modern (e.g. functional or phylogenetic diversity), and applied approaches (e.g. effects of climate change, changes of land use, or land management) to study social insect communities.
ZOOM LINK: https://univ-tlse3-fr.zoom.us/j/97390570715 PROGRAMME (London time: UTC+1):
ABSTRACTS:
Competition or dominance hierarchies and straw men in ant community ecology Kari Vepsäläinen Retuperä Biological Station, Nuuksio, Finland The role of competition in structuring of ant communities has been with us in publications from the 1950’s. Four decades ago Vepsäläinen and Pisarski (1982) suggested that a conceptual, explanatory framework based on dominance or competition hierarchies of ant species may help to understand patterns of ant communities and their structuring. The usefulness of such conceptual framework is tested by its capacity to generate meaningful, testable hypotheses to increase our understanding of patterns and processes. Useful explanatory frameworks are road maps to solutions, rather than solutions themselves. When indispensable elements like competition and the concept of competition hierarchies are understood as universal pattern accounts, no progress in understanding is gained. On the contrary, lack of understanding may lead to re-defining the conceptual framework of competition hierarchies as a monolithic process which governs community organisation. After re-definition it is easy to claim that it may be time for ant ecologists to move on from dominance hierarchies. In my talk I will show how awry this interpretation is from the original concept, and then explain why the original still may be useful.
Global evidence for taxa and community-level convergence in the ants Tom R. Bishop*1, Rob R. Dunn2, Heloise Gibb3, Catherine L. Parr1, Nathan J. Sanders4 & GlobalAnts authors 1 Dept of Earth, Ocean and Ecological Sciences, University of Liverpool, UK 2 Dept of Applied Ecology, NorthCarolina State University, Raleigh, NC, USA 3 Dept of Ecology, Environment and Evolution, La Trobe University, Australia 4 Dept of Ecology and Evolutionary, Biology, University of Michigan, Ann Arbor, USA * e-mail: thomasrhys.bishop@gmail.com Convergence is the phenomenon whereby Life repeatedly evolves similar phenotypes in response to similar selection pressures. These convergence events hint at an underlying determinism in biotic evolution, and as such, understanding them may allow us to predict future evolutionary and ecological dynamics. Convergence is typically studied at the taxa-level where distantly related lineages of organisms independently converge on the same set of phenotypic traits. However, convergence can also take place at the community-level where distantly located ecological communities converge on similar structures and trait distributions. Modern approaches focus on untangling fine-scale patterns in taxa convergence but we have limited understanding of how general both taxa and community convergence is at large taxonomic and geographic scales. Here, we provide a global, quantitative test of the prevalence and drivers of convergence in a functionally important insect group: the ants. Our analyses reveal that while ants have convergently evolved to specialise on various microhabitat and dietary niches, this level of convergence is not significantly different from a randomly evolving null model. At the community level, however, we find much higher levels of convergence than expected by chance. Furthermore, the degree of community convergence is most strongly linked to environmental similarity – ant communities in more similar environments tend to share similar trait distributions. These results highlight that at the global scale, taxa-level convergence can happen purely by chance, but that community-level convergence is real, widespread, and driven by the environment.
Evaluating the conservation value of sacred forests for ant taxonomic, functional and phylogenetic diversity in highly degraded landscapes Sabine S. Nooten * 1, 2, Roger H. Lee1 and Benoit Guénard1 1 IBBL, School of Biological Sciences, The University of Hong Kong 2 Current affiliation: Department of Animal Ecology and Tropical Biology, University of Würzburg, Würzburg, Germany * e-mail: sabine.nooten@gmail.com Land use changes and accelerating deforestation impact biodiversity worldwide. It is well established that the loss of primary forests is devastating, but considerably less is understood about the conservation value of sacred forests (e.g. Feng shui woods in China) as local biodiversity reservoirs in human-influenced landscapes. We address this knowledge gap by evaluating several dimensions of ant biodiversity in Hong Kong Feng shui woods. We compare taxonomic, phylogenetic and functional elements of leaf litter dwelling ants, collected over five years among Feng shui woods and two successional woody habitats. Ant assemblages in Feng shui woods presented higher species richness that were more resilient to invasions by tramp species, and encompassed specialist species with a distinct set of traits. Phylogenetic diversity was similar in Feng shui and successional woods, but functional diversity was clustered in early successional habitats. The scarcity of tramp species and presence of specialists in Feng shui woods despite their close proximity to human settlements highlights their conservation value for native species in degraded landscapes. Our results provide much needed insight on the faunal biodiversity of Feng shui woods. We highlight the conservation value and urgent need for a better protection of these widely overlooked sacred forests.
The role of Tetramoriom immigrans in monitoring urban biodiversity Martina Ghizzoni*, Fiorenza A. Spotti, Cristina Castracani, Donato A. Grasso, Alessandra Mori University of Parma - Department of Chemical Sciences of Life and Environmental Sustainability, Parco Area delle Scienze 11/a, 43124 Parma, Italy * e-mail: martina.ghizzoni@unipr.it Tetramorium immigrans (Santschi, 1927) is the most abundant ant species in several European and North American environments, including the urban ones. In Europe, a recent study analyzed the influence of urbanization on the distribution of T. immigrans in France, while the Italian situation remains unexplored. In this study, the first investigation on T. immigrans distribution in Italian urban environments was carried out collecting data from two categories of green areas in the city of Parma. For each species within the ant communities, abundance and occurrence were assessed using pitfall traps, whereas baits were used to study interspecific competition. Results outlined differences between the ant communities of the green areas and showed that although T. immigrans was the most abundant and frequent species, its abundance and occurrence differed according to the green areas. Moreover, T. immigrans discovered and monopolized the majority of baits, but aggression played a minor role among all observed interactions, suggesting thatits competitive success was achieved through its numerical dominance rather than the behavioral one. In conclusion, our results suggested that ants could be promising indicators of urban biodiversity and could give useful information for urban green areas management and a sustainable development of the city.
Succession of ant communities (Hymenoptera: Formicidae) in a limestone quarry from center of Romania Ioan Tăușan *, Maria Stănciugelu Department of Environmental Sciences and Physics, Faculty of Sciences, Lucian Blaga University of Sibiu, Romania * e-mail: ioan.tausan@ulbsibiu.ro Human impact is widely distributed and has raised up concerns in terms of biodiversity loss. Amongst the most important human impact we highlight forest clear-cuts, fires, habitat fragmentation and quarry exploitation. Ants are often use in monitoring studies, being considered a key component of terrestrial ecosystems. We conducted a field survey using pitfall traps in a limestone quarry from center of Romania in the summer of 2020. We applied the Space for Time Substitution in order to understand the overall mechanism of ecological succession of the ant communities in a limestone quarry. Four succession stages were used: T1 – no vegetation cover, T2 – vegetation cover installed after 5 years, T3 – vegetation cover installed after 10 years and T4 – forest habitats that were present before the exploration of the limestone quarry. Altogether, we identified 14 ant species belonging to for subfamilies. The most abundant species was Myrmica rubra and Formica cunicularia which are quite tolerant species. Most of the species are tolerant of high temperatures that characterized the first stages of succession where the vegetation was poorly represented. We highlight the presence of sub-Mediterranean elements such as Aphaenogaster subterranea. The most different stages was, as expected, the forest habitats, where T1 was also very different due to the lack of vegetation cover where ubiquitous species occurred.
Floral selection in mountain bumble bees and a test of the ‘target use hypothesis’ Douglas B. Sponsler * 1, Katharina Kallnik1, Fabrice Requier2, Alice Claßen1, A. Fabienne Maihoff1, Johanna Sieger 3, Ingolf Steffan-Dewenter1 1 Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, Würzburg, Germany * e-mail: douglas.sponsler@uni-wuerzburg.de Understanding patterns of resource use by animals, and the underlying selection processes that govern these patterns, can clarify how ecological communities have assembled in the past, how they currently function, and how they are likely to respond to future perturbations. Communities of bumble bees and their floral hosts provide a tractable and compelling system in which to study questions of resource use, and the answers to these questions have immediate relevance to the conservation of bumble bees and their mutualists under the forcings of climate and land use change, particularly in mountain ecosystems. Using a dataset consisting of ~13,000 interactions recorded along a 1400 m elevation gradient over three consecutive years, we analyze bumble bee resource selection in terms of floral morphotype. We find that most bumble bee species exhibit strong positive selection toward flowers of the bell, lip, and/or flag morphotypes. Species-level preferences for floral morphotypes were explained well by bumble bee tongue length, which is well-established a key matching trait that constrains bumble bee floral choice. Tongue length was a much stronger predictor of null-model-corrected visitation rates than of raw visitation rates, indicating that, contrary to the target use hypothesis, neutral effects of resource abundance function in conjunction with learned or innate floral biases to determine bumble bee floral choice. By modeling floral selection through elevation and time, we demonstrate strong dynamics of resource availability and resource selection, suggesting that bumble bees have evolved flexible morphotype preferences suited to the extreme spatiotemporal floristic turnover of mountain ecosystems. Patterns of resource availability and selection through elevation and time are likely to be distorted in coming decades by the simultaneous processes of climate and land use change, which together cause the displacement and redistribution of mountain floral communities.
Conflict of interest during nest selection is resolved through majority concession Harikrishnan Rajendran*, Amir Haluts, Nir Gov, Ofer Feinerman Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot, Israel * e-mail: harikrishnan.rajendran@weizmann.ac.il Performing collective decisions, whereby a consensus is reached between several available options, is crucial for many social animals. However, during group decision-making, the actions of certain individuals may lead to a conflict of interest, resulting in competition and social division. Such conflict arises, for example, if some group members do not align with the majority, and remain stubborn in their decisions. In this study, we impose a conflict of interest between individuals in an emigrating ant colony and elucidate the mechanisms of conflict resolution. The conflict is induced using an automatic gate system, which permits only a fraction of the colony to enter the superior nest, while complete colony cohesion is only possible in the inferior nest. We construct an empirically motivated model that reveals how independent decisions are integrated, and how the colony evolves to form collective stable states. The model predicts a dependence of the decision outcome on colony size, which we verify in experiments. We further show that the imposed conflict is resolved through 'majority concession', where a majority of permitted ants sacrifice the benefit of a better quality choice to reach a consensus. This decision emphasizes the importance of group cohesion in eusocial societies.
Are drone congregation areas real? Harmonic radar tracking reveals the mating flights of honeybee drones Joseph L. Woodgate* 1, James C. Makinson 1,3, Natacha Rossi 1, Ka S. Lim 2, Andrew M. Reynolds 2, Christopher J. Rawlings 2, Lars Chittka 1 1School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK. 2Department of Computational and Analytical Sciences, Rothamsted Research, Harpenden, AL5 2JQ, UK. 3Present address: Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales, Australia. * e-mail: j.woodgate@qmul.ac.uk Male honeybees (drones) are thought to congregate in large numbers in particular “drone congregation areas” to mate. This hypothesis remains controversial since most evidence comes from the use of caged queens or pheromone lures to attract drones and some authors argue that these lures could themselves be the cause of congregations. We used harmonic radar to record the flight paths of individual drones, for the first time, and found clear evidence that drones favoured certain locations within the landscape which were stable over two years. Surprisingly, drones often visit multiple potential lekking sites within a single flight and take shared flight paths between them. Flights between such sites are relatively straight and begin as early as the drone’s second flight, indicating familiarity with the sites acquired during initial learning flights. Arriving at congregation areas, drones display convoluted, looping flight patterns. We found a correlation between a drone’s distance from the centre of each area and its acceleration toward the centre, a signature of collective behaviour leading to congregation in these areas. Our study reveals that drones navigate between and within multiple aerial leks.
Phylogeography of the Neotropical soil-feeding termites Embiratermes neotenicus and E. chagresi Damien Gergonne * 1,2,3,4, Romain Fougeyrollas 2,3,4, Chantal Poteaux 1, Yves Roisin 5, Inge Armbrecht 6, Jan Šobotník 7, Cynthia S. Valladares Romero 8, Juliette M. Berthier 9, David Sillam-Dussès 1, Virginie Roy 2,3,4 1 Université Sorbonne Paris Nord, Laboratoire d’Ethologie Expérimentale et Comparée, LEEC, UR 4443, 99 avenue Jean-Baptiste Clément, F-93430, Villetaneuse, France 2 Paris Est Créteil, CNRS, INRAE, IRD, IEES, F-94010 Créteil, France 3 Sorbonne Université, IEES, F-75005 Paris, France 4 Université de Paris, IEES, F-75013 Paris, France 5 Université Libre de Bruxelles, Evolutionary Biology and Ecology, avenue F.D. Roosevelt, 50, CP 160/12, B-1050 Brussels, Belgium 6 Universidad del Valle, Facultad de Ciencias Naturales y Exactas, Ciudadela Universitaria Meléndez, Edificio 320, Cali, Colombia 7 Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, Prague, Czech Republic 8 Departamento de Ciencias Biológicas, Universidad Técnica Particular de Loja, Loja, Ecuador 9 University of Kent, School of Anthropology and Conservation, Canterbury, Kent, CT2 7NR, United Kingdom * e-mail: gergonne.damien@gmail.com Among termites, the Syntermitinae subfamily is only known in South America, where termite taxonomy, biology and ecology have only recently been investigated. Here, we focus on the taxonomy and phylogeography of a particularly abundant Neotropical soil-feeding species Embiratermes neotenicus (Termitidae: Syntermitinae) and its sister-species in the literature, Embiratermes chagresi. E. neotenicus was described on a wide geographic range in South-America while E. chagresi was only described in Central-America. However, we recently identified E. chagresi on the pacific coast of Columbia, co-occurring with E. neotenicus. The two species are scarcely morphologically distinguishable but show very distinct mitochondrial lineages. In order to provide a better understanding of the evolutionary processes that act(ed) on the genetic structure of the populations of these termite species, we gathered sterile individuals of both species all around the sympatry zone (Panama, West and East Columbia, Ecuador). We analyzed morphology, mitochondrial (COI, COII, and 16S rRNA genes) and nuclear (ITS2 sequence, Wg gene, and microsatellites) DNA variation. We found mito-nuclear incongruences and highlighted a sympatry zone with admixed individuals. We used these results to infer a biogeographic scenario and we provide new components for the integrative taxonomy and evolutive history of E. neotenicus and E. chagresi.
Ant functional traits: Measuring what’s easy to measure vs. measuring what we need to know to predict community structure. Nathan J. Sanders University of Michigan, USA Spurred on by plant, and increasingly avian, ecologists, ant ecologists have turned to measuring functional traits in ants with the hope of being able to better understand ant community structure and how ant biodiversity might respond to global change. Plant ecologists have typically focused on six functional traits that are generally correlated with resource economics and plant size: adult plant height, leaf area, seed mass, leaf mass per area, leaf nitrogen, and leaf dry matter content. Importantly, these plant traits are clearly linked to performance and fitness, both within and among species, and influence a variety of ecosystem functions including primary productivity, carbon storage, and nutrient cycling. But what functional traits do we measure in ants? And what do those traits tell us, if anything? And are they related to any ecosystem functions? |
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