Tomer Joseph Czaczkes

Tomer Joseph Czaczkes
Universität Regensburg | UR · Institute of Zoology

Doctor of Philosophy

About

82
Publications
21,045
Reads
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1,284
Citations
Introduction
My research falls into four overlapping categories, all using ants (mainly Lasius niger and Linepithema humile) as a model system: - Strategic information use - Comparative psychology - Collective decision making - Other cool stuff I feel like looking at: pooping behaviour, web building, pheromone following
Additional affiliations
April 2016 - present
Universität Regensburg
Position
  • Group Leader
January 2013 - present
Universität Regensburg
Position
  • PostDoc Position
Description
  • http://www-evolution.uni-regensburg.de/Staff/TomerCzaczkes/index.html or http://scholar.google.com/citations?user=5fY0Y6oAAAAJ&hl=en
October 2008 - October 2012
University of Sussex
Position
  • Foraging organisation in ants
Description
  • for more details, see my complete thesis, which I have uploaded onto Researchgate. There is an abstract of the thesis in there too.

Publications

Publications (82)
Article
Full-text available
Cooperative transport, defined as multiple individuals simultaneously moving an object, has arisen many times in ants, but is otherwise extremely rare in animals. Here we review the surprisingly sparse literature available on cooperative transport. Cooperative transport abilities in ants are a continuum, but three general syndromes are described: u...
Article
Trail pheromones do more than simply guide social insect workers from point A to point B. Recent research has revealed additional ways in which they help to regulate colony foraging, often via positive and negative feedback processes that influence the exploitation of the different resources that a colony has knowledge of. Trail pheromones are ofte...
Article
Full-text available
Humans usually assess things not according to their absolute value, but relative to reference points – a main tenant of Prospect Theory. For example, people rate a new salary relative to previous salaries and salaries of their peers, rather than absolute income. We demonstrate a similar effect in an insect: ants expecting to find low-quality food s...
Article
When personally gathered and socially acquired information conflict, animals often prioritize private information. We propose that this is because private information often contains details that social information lacks. We test this idea in an ant model. Ants using a food source learn its location and quality rapidly (private information), whereas...
Preprint
Full-text available
How we treat animals is strongly influenced by our understanding of their cognitive abilities, and thus accurately assessing cognitive abilities has large ethical and policy implications. Bees have become perhaps the most important model group for studying complex cognition in invertebrates, and show a broad variety of impressive cognitive abilitie...
Preprint
Full-text available
Behavioural economists have identified many psychological manipulations which affect perceived value, although value in humans is not a unitary experience, with “liking” and “wanting” being neurologically separate processes. A prominent example of this is bundling, in which several small gains (or costs) are experienced as more valuable (or costly)...
Preprint
Full-text available
The Argentine ant ( Linepithema humile ) is one of the most damaging and widespread invasive ant species worldwide. However, control attempts often fail due to insufficient bait uptake, or bait abandonment. Increasing preference for, and consumption of, is thus an important requirement for successful control. Associative learning and within-nest in...
Article
Full-text available
Animals must often decide between exploiting safe options or risky options with a chance for large gains. Both proximate theories based on perceptual mechanisms, and evolutionary ones based on fitness benefits, have been proposed to explain decisions under risk. Eusocial insects represent a special case of risk sensitivity, as they must often make...
Article
Response conflicts occur when the correct goal-congruent response is weaker than an alternative but incorrect response. To overcome response conflicts, the stronger response has to be inhibited, making the study of response conflicts an important research topic in higher order cognition. Response conflicts often result in conflict interference-an i...
Article
Full-text available
Learning allows animals to respond to changes in their environment within their lifespan. However, many responses to the environment are innate, and need not be learned. Depending on the level of cognitive flexibility an animal shows, such responses can either be modified by learning or not. Many ants deposit pheromone trails to resources, and inna...
Article
Full-text available
• In insect societies, the balance between exploitation of known resources and exploration of new ones is important to ensure sufficient resources. • Mass recruiting ants, such as Lasius niger, use pheromone trails to recruit nestmates to a newly discovered food source. Pheromone following, however, shows characteristic non‐following (lapse) rates...
Article
Full-text available
Insects can be very good learners. For example, they can form associations between a cue and a reward after only one exposure. Discrimination learning, in which multiple cues are associated with different outcomes, is critical for responding correctly complex environments. However, the extent of such discrimination learning is not well explored. St...
Article
Full-text available
Comparing the value of options is at the heart of economic decision-making. While an option may have an absolute quality (e.g. a food source has a fixed energy content), the perceived value of the option may be malleable. The factors affecting the perceived value of an option may thus strongly influence which option is ultimately chosen. Expectatio...
Article
We humans sort the world around us into conceptual groups, such as 'the same' or 'different', which facilitates many cognitive tasks. Applying such abstract concepts can improve problem-solving success and is therefore worth the cognitive investment. In this study, we investigated whether ants (Lasius niger) can learn the relational rule of 'the sa...
Article
In order to make effective collective decisions, ants lay pheromone trails to lead nest-mates to acceptable food sources. The strength of a trail informs other ants about the quality of a food source, allowing colonies to exploit the most profitable resources. However, recruiting too many ants to a single food source can lead to over-exploitation,...
Article
Full-text available
Humans usually assess options not in terms of absolute value, but relative to reference points. The framing of alternatives can strongly affect human decision-making, leading to different choices depending on the context within which options are presented. Similar reference-point effects have been recently reported in ants, in which foragers show c...
Article
Engineered paths increase efficiency and safety but also incur construction and maintenance costs, leading to a trade-off between investment and gain. Such a trade-off is faced by Australian meat ants, which create and maintain vegetation-free trails between nests and food sources, and thus their trails are expected to be constructed selectively. T...
Article
Animals may gather information from multiple sources, and these information sources may conflict. Theory predicts that, all else being equal, reliance on a particular information source will depend on its information content relative to other sources. Information conflicts are a good area in which to test such predictions. Social insects, such as a...
Preprint
Full-text available
Humans usually assess things not in terms of absolute value, but relative to reference points. The framing of alternatives can strongly affect human decision-making, leading to different choices depending on the context within which options are presented. Similar reference-point effects have been recently reported in ants, in which foragers show a...
Article
Full-text available
Foraging animals use a variety of information sources to navigate, such as memorised views or odours associated with a goal. Animals frequently use different information sources concurrently, to increase navigation accuracy or reliability. While much research has focussed on conflicts between individually learned (private) information and social in...
Article
Waste disposal is important for maintaining the health of animal societies. Adults and off; spring produce large amounts of waste and feces that could contain pathogens or toxins and may need to be stored away from the young or adult individuals. In social insects, the worker caste is responsible for nest maintenance, including sanitary behavior, an...
Preprint
Full-text available
Animals must often decide between exploiting safe options or risky options with a chance for large gains. While traditional optimal foraging theories assume rational energy maximisation, they fail to fully describe animal behaviour. A logarithmic rather than linear perception of stimuli may shape preference, causing animals to make suboptimal choic...
Article
Communication is the foundation of all social systems, and learning is perhaps the most important cognitive tool. But how do these two critical faculties interact? With social insects being some of the best learners of the invertebrate world, and indisputably the most communicative, we examine the role of learning and experience in social insect co...
Preprint
Full-text available
Animals may gather information from multiple sources, and these information sources may conflict. Theory predicts that, all else being equal, reliance on a particular information source will depend on its information content relative to other sources. Information conflicts are a good area in which to test such predictions. Social insects, such as a...
Preprint
Animals have access to many alternative information sources when making decisions, such as private information (e.g. memory) and social information. Social insects make extensive use of social information. However, when intentional social information (e.g. pheromone trails in ants) conflicts with private information (e.g. route memories), insects o...
Article
Increased urbanisation is leading to a rise in light pollution. Light pollution can disrupt the behaviour and physiology of animals resulting in increased mortality. However, animals may also benefit from artificial light sources, as these may aggregate prey or signal suitable environments. For example, spiders are commonly seen congregating around...
Article
Full-text available
Social insects frequently make important collective decisions, such as selecting the best food sources. Many collective decisions are achieved via communication, for example by differential recruitment depending on resource quality. However, even species which only rarely recruit can respond to a changing environment on a collective level by tracki...
Article
Full-text available
Underground ant nests are constructed by decentralised self-organisation wherein the ants respond to local stimuli and produce coordinated structures through globally regulated behaviours. One such regulation is the reduction in digging effort that occurs when available nest space has reached an adequate size. Tunnels have a distinct configuration...
Article
Full-text available
To make sensible decisions, both humans and other animals must compare the available options against a reference point-either other options or previous experience. Options of higher quality than the reference are considered good value. However, many perceptible attributes of options are value-neutral, such as flower scent. Nonetheless, such value-n...
Article
Full-text available
In the original publication of the article, the ORCID ID of author Stefan Popp was incorrect. The correct ORCID ID is given below: © 2018 International Union for the Study of Social Insects (IUSSI)
Article
Full-text available
When faced with multiple competing goals, individuals must decide which goal to attend to. Voluntary task switching is an important paradigm for testing cognitive flexibility and spontaneous decision-making when competing tasks are present. Of particular importance is the study of how reward affects task switching, as reward is perhaps the most com...
Preprint
Full-text available
When choosing between two options, a sensible strategy is to choose the highest value option. To do this, both options must be evaluated and compared. The way value is judged and utility is perceived therefore has strong effects on which option is chosen. Traditionally, value was considered absolute. However, research on human decision-making sugge...
Chapter
Full-text available
Ant Colony Optimization (ACO) is a widespread optimization technique used to solve complex problems in a broad range of fields, including engineering, software development and logistics. It was inspired by the behaviour of ants which can collectively select the shorter of two paths leading to a food source. They are able to do so even without any s...
Article
T- and Y-mazes are powerful tools for studying the behavioural ecology and cognition of animals, especially ants. Such mazes are cheap, easy to deploy, and very flexible, allowing diverse subjects to be studied. These include cue and route learning, pheromone following, and testing for cognitive abilities such as associative and concept learning. H...
Article
Expending effort is generally considered to be undesirable. However, both humans and vertebrates will work for a reward they could also get for free. Moreover, cues associated with high-effort rewards are preferred to low-effort associated cues. Many explanations for these counterintuitive findings have been suggested, including cognitive dissonanc...
Article
Full-text available
Chemical signals play a crucial role in reproduction as a means for locating mates and/or gaining information about their quality, ultimately affecting mating system dynamics and mate choice. In spiders, one of the potential sources of chemical signalling is silk. However, while female silk is known to attract mates and/or elicit courtship, due to...
Preprint
Social insects frequently make important collective decisions, such as selecting the best food sources. Many collective decisions are achieved via communication, for example by differential recruitment depending on resource quality. However, even species without recruitment can respond to a changing environment on collective level by tracking food...
Article
Reproductive division of labor is a defining feature of all eusocial organisms. In the eusocial insects, non-reproductive labor is often also divided into safe tasks within the nest, such as nursing, and risky extranidal tasks, such as scouting and foraging. Within-nest (intranidal) tasks are usually performed by younger workers while older workers...
Article
Full-text available
The idea that ants communicate when meeting on a trail is beguiling, but evidence for this is scarce. Physical communication in ants has been demonstrated to play a role as a modulator of behaviours such as alarm and recruitment. Honeybees can communicate the location of a resource using an advanced motor display—the waggle dance. However, no equiv...
Article
The study of how animals respond to risk has had a strong influence on our understanding of animal behaviour. By risk, we refer to a situation where organisms must exploit a resource with an unstable quality. Animals may have different risk preferences: they may be risk seeking (e.g. prefer a gamble of 2 or 4 versus a safe bet of 3), risk averse or...
Article
Often, the first option is not the best. Self-control can allow humans and animals to improve resource intake under such conditions. Self-control in animals is often investigated using intertemporal choice tasks—choosing a smaller reward immediately or a larger reward after a delay. However, intertemporal choice tasks may underestimate self-control...
Article
Information asymmetry is common in many aspects of natural and economic systems. Collective self-organized behaviour in social insects may involve asymmetries in which an individual may possess information but only another individual is able to act on it. We examined this phenomenon on foraging trails of leaf-cutting ants (Atta colombica) to determ...
Article
Full-text available
The use of pheromone trails in ant colony organization is an important model for understanding collective decision-making and complex adaptive systems. The ant Lasius niger L. (Hymenoptera: Fomicidae) is one of the main model organisms used for such studies. Key to understanding pheromone trail use by ants is knowing how well trails are followed. T...
Article
Full-text available
Route learning is key to the survival of many central place foragers, such as bees and many ants. For ants which lay pheromone trails, the presence of a trail may act as an important source of information about whether an error has been made. The presence of trail pheromone has been demonstrated to support route learning, and the effect of pheromon...
Data
Supplementary figures, and full statistical output. (PDF)
Article
Ant colonies are famous for using trail pheromones to make collective decisions. Trail pheromone systems are characterised by positive feedback, which results in rapid decision making. However, in an iconic experiment ants were shown to become 'trapped' in exploiting a poor food source, if it was discovered earlier. This has conventionally been exp...
Article
Animals must contend with an ever-changing environment. Social animals, especially eusocial insects such as ants and bees, rely heavily on communication for their success. However, in a changing environment, communicated information can become rapidly outdated. This is a particular problem for pheromone trail using ants, as once deposited pheromone...
Article
Individual animals are adept at making decisions and have cognitive abilities, such as memory, which allow them to hone their decisions. Social animals can also share information. This allows social animals to make adaptive group-level decisions. Both individual and collective decision-making systems also have drawbacks and limitations, and while b...
Article
Full-text available
We quantified insect visitation rates by counting how many flowers/inflorescences were probed per unit time for five plant species (four native and one garden: California lilac, bramble, ragwort, wild marjoram, and ivy) growing in Sussex, United Kingdom, by following individual insects (n=2987) from nine functional groups (honey bees (Apis mellifer...
Article
Full-text available
Sanitary behaviour is an important, but seldom studied, aspect of social living. Social insects have developed several strategies for dealing with waste and faecal matter, including dumping waste outside the nest and forming specialised waste-storage chambers. In some cases waste material and faeces are put to use, either as a construction material...
Article
Social animals rely heavily on social cues to make foraging decisions. In social insects such as ants, perceived use of paths by nestmates is an important cue which allows ants to adjust foraging behaviours. Ants that encounter other ants on a trail reduce trail pheromone deposition. This has been predicted to allow ants to preferentially select un...
Article
Ant foraging is an important model system in the study of adaptive complex systems. Many ants use trail pheromones to recruit nestmates to resources. Differential recruitment depending on resource quality coupled with positive feedback allows ant colonies to make rapid and accurate collective decisions about how best to allocate their work-force. H...
Article
Full-text available
Ants are key model organisms in the study of navigation and memory formation. Many ants learn food locations very quickly and with high accuracy. But can individual ants learn multiple separate food locations, associate them with a cue, and then correctly recall the food location and navigate towards it when later presented with that cue? In this e...
Article
Full-text available
During foraging, ant workers are known to make use of multiple information sources, such as private information (personal memory) and social information (trail pheromones). Environmental effects on foraging, and how these interact with other information sources, have, however, been little studied. One environmental effect is trail bifurcation asymm...
Article
Full-text available
Social insects often respond to signals and cues from nest-mates, and these responses may include changes in the information they, in turn, transmit. During foraging, Lasius niger deposits a pheromone trail to recruit nestmates, and ants that experience trail crowding deposit pheromone less often. Less studied, however, is the time taken for signal...
Article
Full-text available
The longhorn crazy ant Paratrechina longicornis is a pest ant species with worldwide distribution. It tends honeydew-producing Hemiptera to obtain carbohydrates and is also an effective predator and scavenger. What strategies does P. longicornis use to aid in hunting and scavenging? Our results show that as well as long-term recruitment to stable f...
Article
Full-text available
Crowding in human transport networks reduces efficiency. Efficiency can be increased by appropriate control mechanisms, which are often imposed externally. Ant colonies also have distribution networks to feeding sites outside the nest and can experience crowding. However, ants do not have external controllers or leaders. Here, we report a self-orga...
Article
Full-text available
Ants are central place foragers and use multiple information sources to navigate between the nest and feeding sites. Individual ants rapidly learn a route, and often prioritize memory over pheromone trails when tested on a simple trail with a single bifurcation. However, in nature ants often forage at locations which are reached via more complex ro...
Article
Full-text available
Positive feedback plays a major role in the emergence of many collective animal behaviours. In many ants pheromone trails recruit and direct nestmate foragers to food sources. The strong positive feedback caused by trail pheromones allows fast collective responses but can compromise flexibility. Previous laboratory experiments have shown that when...
Data
The raw data for the tests presented in Table 2 . (XLSX)
Data
Smallest colony size still showing flexibility under high crowding conditions (8 vs. 24 agents). Proportions of agents foraging at the two food patches, in which the second patch (red line) allowed three times as many agents to feed simultaneously but was made available 900 times steps after agents started foraging at the first food patch (blue lin...
Data
Photo showing the feeder (petri-dish, 5 cm diameter) standing on 2 cm wooden legs. The feeder contained 1 M sucrose solution. Ants could gain access to the solution via 1 mm feeding holes (27 in this situation). (TIF)
Data
Colony size needed for flexibility under low crowding conditions (72 vs. 216 agents). Proportions of agents foraging at the two food patches, in which the second patch (red line) allowed three times as many agents to feed simultaneously but was made available 900 times steps after agents started foraging at the first food patch (blue line). Data av...
Data
The NetLogo computer code of the agent-based simulation model. The file extension “.txt” can be renamed to “.nlogo” to open the file. (TXT)
Data
Model 1 with the different behavioural states being updated in reversed sequence (unloading agents→recruiting agents→dissatisfied agents→feeding agents→foraging agents→idle agents). Proportions of agents visiting two identical food patches each with space for 8, 24, 72 or 216 foraging agents. The blue line represents the patch that had more agents...
Data
The effect of the arm length on flexibility under high crowding conditions (8 vs. 24 agents). Proportions of agents foraging at the two food patches, in which the second patch (red line) allowed three times as many agents to feed simultaneously but was made available 1800 time steps after agents started foraging at the first food patch (blue line)....
Data
The effect of the main branch length on flexibility under high crowding conditions (8 vs. 24 agents). Proportions of agents foraging at the two food patches, in which the second patch (red line) allowed three times as many agents to feed simultaneously but was made available 14000 time steps after agents started foraging at the first food patch (bl...
Data
The effect of the probability of dissatisfied agents to walk to the nest versus to the second feeder on collective flexibility under high crowding conditions (8 vs. 24 agents). Proportions of agents foraging at the two food patches, in which the second patch (red line) allowed three times as many agents to feed simultaneously but was made available...
Article
Communication of feeding locations is widespread in social animals. Many ants use pheromone trails to guide nestmates to food sources, but trail properties and how they are used vary. The ant Pheidole oxyops retrieves prey cooperatively using multiple workers. The recruited workers are guided to the prey by a pheromone trail laid by the initial dis...