Very rapid multi-odour discrimination learning in the ant Lasius niger

Czaczkes, Tomer J.; Kumar, P. Girish

doi:10.1007/s00040-020-00787-0

Cited by 16 publications

(19 citation statements)

References 27 publications

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“…3 & table 1). These findings are again comparable to results from Lasius niger (Czaczkes et al 2014; Czaczkes and Kumar 2020). Somewhat surprisingly, results from both the short-term and long-term learning experiments showed that punishing the alternative odour with quinine does not improve response accuracy.…”

Section: Discussionsupporting

confidence: 89%

A systematic examination of learning in the invasive antLinepithema humilereveals very rapid development of short and long-term memory

Wagner

Galante

Czaczkes

2022

Preprint

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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 information transfer might be a potential tool for achieving this goal. Here, we conducted a detailed and systematic investigation of olfactory learning and side learning in Argentine ants. The ants showed very strong and rapid side learning, choosing the correct arm in a Y-maze 65% of time after just one visit, and 84% correct after two. Odour learning was even more rapid, with just one visit to a flavoured food source, reached by a scented runway, leading to 85% choices for the corresponding scent on a Y-maze. Further experiments demonstrated that having two cues (runway odour and food flavour) does not improve learning significantly over just one cue. This rapid learning is long-lasting, with one exposure to a runway odour associated with a reward resulting in a strong preference (73%) for this odour even after 48 hours. Food flavour information is transferred efficiently between nestmates in the nest, driving preference: naive ants housed with ants fed on flavoured food show a strong preference (77%) for that odour after 24 hours. Our results demonstrate the impressive learning abilities of Linepithema humile, which coupled with efficient intranidal information transfer and strong use of pheromonal recruitment may help explain their ability to discover and then dominate resources. However, these strengths could potentially be used against them, by exploiting learning and information transfer to increase toxic bait uptake during control efforts. Steering ant preference by leveraging learning might be an underappreciated tool in invasive alien species control.

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Section: Discussionsupporting

confidence: 89%

A systematic examination of learning in the invasive antLinepithema humilereveals very rapid development of short and long-term memory

Wagner

Galante

Czaczkes

2022

Preprint

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“…It appears that the effects of hydrocarbon learning are less distinct than those of learning volatile odours (cf. Czaczkes and Kumar, 2020), perhaps because the detection of hydrocarbon cues is possible only over very short distances.…”

Section: Associating Hydrocarbons With a Sucrose Rewardmentioning

confidence: 99%

“…Here, we studied reward learning in the black garden ant Lasius niger. This species has previously been shown to rapidly associate floral odours with sucrose rewards (Czaczkes and Kumar, 2020) and to acquire a preference for food of certain odours (Beckers et al, 1994). It can even be taught to ignore its own trail pheromones through differential conditioning (Wenig et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Appetitive olfactory learning suffers in ants when octopamine or dopamine receptors are blocked

Wissink

Nehring

2021

Journal of Experimental Biology

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Associative learning relies on the detection of coincidence between a stimulus and a reward or punishment. In the insect brain, this process is carried out in the mushroom bodies under control of octopaminergic and dopaminergic neurons. It was assumed that appetitive learning is governed by octopaminergic neurons, while dopamine is required for aversive learning. This view has been recently challenged: Both neurotransmitters are involved in both types of learning in bees and flies. Here, we test which neurotransmitters are required for appetitive learning in ants. We trained Lasius niger workers to discriminate two mixtures of linear hydrocarbons and to associate one of them with a sucrose reward. We analysed the walking paths of the ants using machine learning and found that the ants spent more time near the rewarded odour than the other, a preference that was stable for at least 24 hours. We then treated the ants before learning with either epinastine, an octopamine receptor blocker, or with flupentixol, a dopamine receptor blocker. Ants with blocked octopamine receptors did not prefer the rewarded odour. Octopamine signalling is thus necessary for appetitive learning of olfactory cues, likely because it signals information about odours or reward to the mushroom body. In contrast, ants with blocked dopamine receptors initially learned the rewarded odour but failed to retrieve this memory 24 hours later. Dopamine is thus likely required for long-term memory consolidation, independent of short-term memory formation. Our results show that appetitive olfactory learning depends on both octopamine and dopamine signalling in ants.

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“…L. niger foragers can distinguish between the three presented molarities (Wendt et al 2019). Moreover, in a pilot experiment, we observed that when presented with three different molarities ants do learn all three molarities and their associated odours (see ESM2, Czaczkes and Kumar 2020). Each ant was tested on the Y-maze 5 times, but as in experiment 1, only data from the first test were ultimately used (see ESM2).…”

Section: Experiments 2 -Risk Preference Between Options Of Different Absolute Valuementioning

confidence: 96%

Irrational risk aversion in an ant

et al. 2021

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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 collective decisions based on resource evaluations from many individuals. Previously, colonies of the ant Lasius niger were found to be risk-neutral, but the risk preference of individual foragers was unknown. Here, we tested individual L. niger in a risk sensitivity paradigm. Ants were trained to associate one scent with 0.55 M sucrose solution and another with an equal chance of either 0.1 or 1.0 M sucrose. Preference was tested in a Y-maze. Ants were extremely risk-averse, with 91% choosing the safe option. Based on the psychophysical Weber–Fechner law, we predicted that ants evaluate resources depending on their logarithmic difference. To test this hypothesis, we designed 4 more experiments by varying the relative differences between the alternatives, making the risky option less, equally or more valuable than the safe one. Our results support the logarithmic origin of risk aversion in ants, and demonstrate that the behaviour of individual foragers can be a very poor predictor of colony-level behaviour.

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Very rapid multi-odour discrimination learning in the ant Lasius niger

Cited by 16 publications

References 27 publications

A systematic examination of learning in the invasive antLinepithema humilereveals very rapid development of short and long-term memory

A systematic examination of learning in the invasive antLinepithema humilereveals very rapid development of short and long-term memory

Appetitive olfactory learning suffers in ants when octopamine or dopamine receptors are blocked

Irrational risk aversion in an ant

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