Biology subjects

Feinerman, O.

Publications and source records attributed to Feinerman, O..

5 recordsLinked to original sources

bioRxiv2024

Colony demographics shape nest construction in ants

The ant nest serves as the skeleton of the ant superorganism. Similar to a skeleton, the nest expands as the colony grows and requires repair after catastrophic events. We experimentally compared nest excavation in colonies seeded from a single mated queen and allowed to grow for six months to excavation triggered by a catastrophic event in colonies with fixed demographics, where the age of each worker, including the queen, is known. The areas excavated by equal group sizes differed significantly between these conditions: heterogeneous populations in naturally growing colonies as well as cohorts of young ants dig larger areas than old ant cohorts. Moreover, we find that younger ants tend to dig slanted tunnels while older ants dig straight down. This is a novel form of age polyethism, where an ants age dictates not only her likelihood to engage in a task but also the way she performs the task. We further present a quantitative model that predicts that under normal growth, digging is predominantly performed by the younger ants while after a catastrophe all ants dig to restore lost nest volume. The fact that the nests of naturally growing colonies exhibit slanted tunnels strengthens this prediction. Finally, our results indicate how a colonys demographic and physical history are sketched into the current structure of its nest.

animal behavior and cognition↗

bioRxiv2023

Leaderless consensus decision-making determines cooperative transport direction in weaver ants

Animal groups need to achieve and maintain consensus to minimise conflict among individuals and prevent group fragmentation. An excellent example of a consensus challenge is cooperative transport, where multiple individuals cooperate to move a large item together. This behavior, regularly displayed by ants and humans only, requires individuals to agree on which direction to move in. Unlike humans, ants cannot use verbal communication but most likely rely on private information and/or mechanical forces sensed through the carried item to coordinate their behaviour. Here we investigated how groups of weaver ants achieve consensus during cooperative transport using a tethered-object protocol, where ants had to transport a prey item that was tethered in place with a thin string. This protocol allows the decoupling of the movement of informed ants from that of uninformed individuals. We showed that weaver ants pool together the opinions of all group members to increase their navigational accuracy. We confirmed this result using a symmetry-breaking task, in which we challenged ants with navigating an open-ended corridor. Weaver ants are the first reported ant species to use a wisdom of the crowd strategy for cooperative transport, demonstrating that consensus mechanisms may differ according to the ecology of each species.

animal behavior and cognition↗

bioRxiv2022

Emergent regulation of ant foraging frequency through a computationally inexpensive forager movement rule

1Ant colonies regulate foraging in response to their collective hunger, yet the mechanism behind this distributed regulation remains unclear. Previously, by imaging food flow within ant colonies we showed that the frequency of foraging events declines linearly with colony satiation ([1]). Our analysis implied that as a forager distributes food in the nest, two factors affect her decision to exit for another foraging trip: her current food load and its rate of change. Sensing these variables can be attributed to the foragers individual cognitive ability. Here, new analyses of the foragers trajectories within the nest imply a different way to achieve the observed regulation. Instead of an explicit decision to exit, foragers merely tend toward the depth of the nest when their food load is high and toward the nest exit when it is low. Thus, the colony shapes the foragers trajectory by controlling her unloading rate, while she senses only her current food load. Using an agent-based model and mathematical analysis, we show that this simple mechanism robustly yields emergent regulation of foraging frequency. These findings demonstrate how the embedding of individuals in physical space can reduce their cognitive demands without compromising their computational role in the group.

animal behavior and cognition↗

bioRxiv2019

Colony entropy - Allocation of goods in ant colonies

Allocation of goods is a key feature in defining the connection between the individual and the collective scale in any society. Both the process by which goods are to be distributed, and the resulting allocation to the members of the society may affect the success of the population as a whole. One of the most striking natural examples of a highly successful cooperative society is the ant colony which often acts as a single superorganism. In particular, each individual within the ant colony has a \"communal stomach\" which is used to store and share food with the other colony members by mouth to mouth feeding. Sharing food between communal stomachs allows the colony as a whole to get its food requirements and, more so, allows each individual within the colony to reach its nutritional intake target. The vast majority of colony members do not forage independently but obtain their food through secondary interactions in which food is exchanged between individuals. The global effect of this exchange is not well understood. To gain better understanding into this process we used fluorescence imaging to measure how the collected food is distributed and homogenized within a Camponotus sanctus ant colony. Using entropic measures to quantify food-blending, we show that while collected food flows into all parts of the colony it homogenizes only partly. We show that mixing is controlled by the ants interaction rule in which only a fraction of the maximal potential is actually transferred. This rule leads to a robust blending process: i.e., neither the exact food volume that is transferred, nor the interaction schedule are essential to generate the global outcome. Finally, we show how the ants interaction rules may optimize a trade-off between fast dissemination and efficient mixing.\n\nAuthor summaryWe study how food is distributed in colonies of ants. Food collected by a small fraction of ants is distributed throughout the colony through a series of mouth-to-mouth interactions.\n\nAn interesting interplay exists between food dissemination and food mixing within the colony. High levels of dissemination are important as they ensure that any food type is available to any ant. On the other hand, high dissemination induces mixing and this reduces the required variety of nutritional choices within the colony.\n\nTracking fluorescent-labelled food and interpreting the results within concepts of information theory, we show that food collected by each forager reaches almost every ant in the colony. Nonetheless, it is not homogenized across workers, resulting in a limited level of mixing.\n\nWe suggest that the difference in food mixture held by each individuals can provide ants the potential to control their nutritional intake by interacting with different partners.

animal behavior and cognition↗

bioRxiv2018

Demography and behavior of polygyne nests of the supercolonial Cataglyphis niger: Does kinship matter?

The basic ant colony is presumed to have evolved through kin selection. However, ants show a remarkable diversity in their social organization, from a monogynous-monandrous queen to the more derived states of polygyny with polyandrous queens. The existence of polygyny is an evolutionary enigma, since kin selection theory predicts that while queens should strive for reproductive monopoly, workers are predicted to favor their own matriline in rearing gynes. Using a barcoding system that enables tracking of individual interactions, along with polymorphic DNA microsatellite markers that indicate the matriline and patriline of all individuals, we demonstrate the complex social interactions in polygyne nests of Cataglyphis niger. C. niger is not only polygyne but also constitutes a supercolony at the study site. Our pioneering findings that both queens and workers are not necessarily related to each other support the supercolony structure of the population. Also in line with supercoloniality, we demonstrate that the workers contribute equally to the nest production and rearing of the queens. Unlike invasive supercolonial species, C. niger is native to Israel, raising questions about the driving forces, apart from kin selection, that stabilize this society.

animal behavior and cognition↗