Chaim Lasmar is a postdoc at Universidade Federal de Lavras. He is an ecologist with a particular interest in ants and their contribution to ecosystem function. Chaim shares his recent work on the variable foraging behaviour of ants across large spatial scales and across different ecoregions in the neotropics.
Chaim Lasmar in his typical habitat.
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Institute. Universidade Federal de Lavras, Brazil
Academic life stage. Postdoc
Research themes. Community Ecology, Macroecology, Biogeography, Landscape Ecology, Ants.
Current study system. Ants play important roles in the ecosystem by interacting with several abiotic and biotic factors to obtain resources. Through their foraging activities, ants are important components of terrestrial ecosystems as seed dispersers, granivores, scavengers, predators and for the cycling of nutrients. Additionally, they are mega abundant and diverse, easy to sample and present different feeding habits and diets by consuming several nutrients such as sugar, amino acids, lipids and sodium. Therefore, they are an excellent model organism to understand diversity patterns such as foraging behaviours that may give us insights into the ecosystem functioning.
Recent paper in JBI. Lasmar, C.J., Bishop, T.R., Parr, C.L., Queiroz, A.C.M., Schmidt, F.A. and Ribas, C.R. (2021), Geographical variation in ant foraging activity and resource use is driven by climate and net primary productivity. J Biogeogr. https://doi.org/10.1111/jbi.14089
Motivation behind this paper. Studies in the lab and a few in the field have demonstrated how ants can change their resource use according to the climate and the availability of plant resources. However, most field studies have been performed at small spatial scales. The remaining large spatial scales studies mainly focused on effects of temperature and productivity in similar habitats or evaluated only a few resource types (e.g., sugar and amino acids or sugar and sodium). Thus, there are still knowledge gaps in terms of whether previous findings hold when assessing foraging behaviour at large spatial scales in different ecoregions. Thus, we decided to assess ant foraging behaviour at large spatial scales and in different ecoregions in the neotropics, which are generally poorly studied in terms of ant foraging behaviour.
Chaim placing baited tubes in the Cerrado savannah forest.
Key methodologies. We used a classic baiting approach to assess the influence of climate and productivity on ant foraging activity and resource use. We provided ants four types of resources, sugar, lipids, amino acids and sodium in 60 transects distributed in six Brazilian biomes that were distinct in terms of climate and productivity. By placing 1500 baited tubes for ants, we obtained estimates of overall ant foraging activity and we could also assess the relative use of each resource type in comparison to the other three. We also assessed the current weather and annual and monthly climate and productivity for each of our transects.
Major results. We made a step forward in our understanding of foraging behaviour by demonstrating how ant foraging activity and resource use was driven by climate and primary productivity at large spatial scales. We suggest that precipitation, temperature seasonality and productivity influence the availability of resources. This resulted in patterns of relative resource use that we considered largely as a trade-off between sugar (where energy availability was low), and amino acids and sodium (where energy availability was high). Temperature likely influenced relative amino acid and lipid use by acting on the physiology of ants. Given that ant foraging activity and resource use involves numerous biotic and abiotic interactions, we suggest that it is conceivable that global climate change and changes in productivity may shift these patterns in foraging behaviour. In turn, changes to foraging could result in changes in ant-mediated ecosystem functions.
Pheidole fracticeps workers (left) and Ectatomma brunneum (right) visiting baited tubes with a cotton ball soaked with lipids in Pantanal
Challenges overcome. Although I had a lot of fun traveling to, and experiencing, the Brazilian biomes, it was challenging to perform the fieldwork at some places. Our research required a huge sampling effort. Sometimes it was not easy to walk along a 750 m transect in the forest while carrying heavy bags full of baited tubes. Some study areas were in very remote places. In the Amazon, for example, there was no road to access the areas and we had to set all transects by foot. This research would not have been possible without the help of many other researchers in the field, and I would like to thank them for their efforts.
Next steps. There are some remaining knowledge gaps concerning the foraging behaviour of ants at large spatial scales. Ant foraging activity is intimately liked to species richness and we were not able to disentangle the direct influence of ecological drivers on foraging activity from the influence of ant species richness. Additionally, it is known that ant resource use also changes across different habitat strata at local scales. Thus, disentangling the relationship between ant species richness, foraging activity and their relation to ecological drivers across habitat strata will certainly contribute to understanding ant foraging behaviour.
Pampa forest habitat.
Pantanal wetland.
If you could study any organism on Earth, what would it be? Well, I think I am very satisfied studying ants and intend to keep studying them for a long time. Recently I started to study (besides ants) other invertebrates (e.g., other insects and spiders) and large mammals, which I also enjoyed. But it would really be great if one day I could also study trees to comprehend more broadly the ecosystems through different taxa.
Anything else to add? As ecologists, we are used to travelling to incredible wild places all over the world, as we try to understand the systems and processes of our natural environments. Yet once our fieldwork is done and our samples are collected, we leave little for the people who live in and around the natural areas we have visited. It was with this in mind that, in addition to our ecological data collection on ant communities in protected areas, we also included scientific dissemination of our work to local people living around these areas. We targeted rural and municipal schools, speaking to students about the importance of biodiversity conservation in Brazil and highlighting the significant role ants play in the ecosystem. We feel this is critical work, particularly as we face a strong wave of science denialism and because Brazil hosts between 15-20% of the world’s biodiversity which has been under severe attacks.
(left) Amazon forest. (right) Atlantic forest.