scholarly journals Negative feedback: ants choose unoccupied over occupied food sources and lay more pheromone to them

2020 ◽  
Vol 17 (163) ◽  
pp. 20190661 ◽  
Author(s):  
Stephanie Wendt ◽  
Nico Kleinhoelting ◽  
Tomer J. Czaczkes
Keyword(s):  
Food Intake ◽  
Negative Feedback ◽  
Visual Cues ◽  
Food Source ◽  
Mate Recognition ◽  
Food Sources ◽  
Lasius Niger ◽  
Surface Lipid ◽  
Feedback Systems ◽  
Pheromone Trails

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, queuing, and thus decreased food intake for the colony. The nonlinear nature of pheromonal recruitment can also lead colonies to become trapped in suboptimal decisions, if the environment changes. Negative feedback systems can ameliorate these problems. We investigated a potential source of negative feedback: whether the presence of nest-mates makes food sources more or less attractive. Lasius niger workers were trained to food sources of identical quality, scented with different odours. Ants fed alone at one odour. At the other odour ants fed either with other feeding nest-mates, or with dummy ants (black surface lipid-coated glass beads). Ants tended to avoid food sources at which other nest-mates were present. They also deposited less pheromone to occupied food sources, suggesting an active avoidance behaviour, and potentiating negative feedback. This effect may prevent crowding at a single food source when other profitable food sources are available elsewhere, leading to a higher collective food intake. It could also potentially protect colonies from becoming trapped in local feeding optima. However, ants did not avoid the food associated with dummy ants, suggesting that surface lipids and static visual cues alone may not be sufficient for nest-mate recognition in this context.

scholarly journals Same length, different shapes: ants collectively choose a straight foraging path over a bent one

2018 ◽  
Vol 14 (3) ◽  
pp. 20180070 ◽  
Author(s):  
Olivier Bles ◽  
Thibault Boehly ◽  
Jean-Louis Deneubourg ◽  
Stamatios C. Nicolis
Keyword(s):  
Food Source ◽  
Abrupt Change ◽  
Food Sources ◽  
Lasius Niger ◽  
Straight Path ◽  
Change Of Direction ◽  
Collective Decisions ◽  
Different Shapes ◽  
Theoretical Results ◽  
Pheromone Trail

In socials insects, exploration is fundamental for the discovery of food resources and determines decision-making. We investigated how the interplay between the physical characteristics of the paths leading to food sources and the way it impacts the behaviour of individual ants affects their collective decisions. Colonies of different sizes of Lasius niger had access to two equal food sources through two paths of equal length but of different geometries: one was straight between the nest and the food source, and the other involved an abrupt change of direction at the midway point (135°). Both food sources were discovered simultaneously, but the food source at the end of the straight path was preferentially exploited by ants. Based on experimental and theoretical results, we show that a significantly shorter duration of nestbound travel on the straight path, which rapidly leads to a stronger pheromone trail, is at the origin of this preference.

scholarly journals Recruitment in Swarm-Founding Wasps:Polybia occidentalisDoes not Actively Scent-Mark Carbohydrate Food Sources

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Benjamin J. Taylor ◽  
Erik V. Nordheim ◽  
Teresa I. Schueller ◽  
Robert L. Jeanne
Keyword(s):  
Visual Cues ◽  
Food Source ◽  
Sucrose Solution ◽  
Search Time ◽  
Scent Marking ◽  
Food Sources ◽  
Foraging Efficiency ◽  
Scent Mark ◽  
Social Bees ◽  
Left Behind

Scent marking food resources is expected to enhance foraging efficiency reducing search time. Many social bees exhibit this behavior, but scent-marking is absent in social wasps, except forVespa mandarinia. We tested for scent marking in the swarm-founding wasp,Polybia occidentalis. This wasp has moderately large colonies and utilizes resources that are concentrated in time and space, making scent marking profitable. Also, this wasp uses chemical markings to lead nestmates to a new nest site during swarm emigration, making it possible that it could use the same behavior to recruit nestmates to a food source. Foragers from 11 colonies were given a choice between a previously visited feeder and an unvisited one, both containing a rich, unscented sucrose solution. There was no difference in the number of visits to the two treatments. However, some individuals chose the feeder on one side more often. We conclude that foragers of this species of wasp do not use odor marks left behind by nestmates to find food, but they do exhibit the tendency, when returning to a food source that has not been depleted, to choose a resource based on its relative position, presumably by using visual cues.

scholarly journals Copy when uncertain: Lower light levels result in higher trail pheromone deposition and stronger reliance on pheromone trails in the ant Lasius niger

2018 ◽  
Author(s):  
Sam Jones ◽  
Tomer J. Czaczkes ◽  
Alan J. Gallager ◽  
Jonathan P. Bacon
Keyword(s):  
Information Content ◽  
Visual Information ◽  
Food Source ◽  
Information Sources ◽  
Information Use ◽  
Information Provision ◽  
Conflict Theory ◽  
Lasius Niger ◽  
Light Levels ◽  
Pheromone Trails

AbstractAnimals 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 ants, make extensive use of both private information (e.g. visual route memories) and social information (e.g. pheromone trails) when attempting to locate a food source. Importantly, eusocial insects collaborate on food retrieval, so both information use and information provision may be expected to vary with the information content of alternative information sources. Many ants, such as Lasius niger, are active both day and night. Variation in light levels represents an ecologically important change in the information content of visually-acquired route information. Here, we examine information use and information provision under high light levels (3200 lux), moderate light levels simulating dusk (10 lux) and darkness (0.007 lux). Ants fail to learn the location of a food source in darkness. As light levels decrease, ants show decreasing reliance on private visual information, and increasing pheromone trail following, consistent with a ‘copy when uncertain’ strategy. In moderate light levels and darkness, pheromone deposition increases, presumably to compensate for the low information content of visual information. Varying light levels for cathemeral animals provides a powerful and ecologically meaningful method for examining information use and provision under varying levels of information content.

scholarly journals Small differences in learning speed for different food qualities can drive efficient collective foraging in ant colonies

2018 ◽  
Author(s):  
F. B. Oberhauser ◽  
A. Koch ◽  
T. J. Czaczkes
Keyword(s):  
Food Quality ◽  
Food Source ◽  
Food Sources ◽  
Lasius Niger ◽  
Agent Based Model ◽  
High Quality ◽  
Agent Based ◽  
Quality Food ◽  
Learning Speed ◽  
Collective Decisions

AbstractSocial 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 source quality.We hypothesised that an apparent collective decision to focus on the highest quality food source can be explained by differential learning of food qualities. Ants may learn the location of higher quality food faster, with most ants finally congregating at the best food source.To test the effect of reward quality and motivation on learning in Lasius niger, we trained individual ants to find a reward of various sucrose molarities on one arm of a T-maze in spring and in autumn after one or four days of starvation.As hypothesised, ants learned fastest in spring and lowest in autumn, with reduced starvation leading to slower learning. Surprisingly, the effect of food quality and motivation on the learning speed of individuals which persisted in visiting the feeders was small. However, persistence rates varied dramatically: All ants in spring made all (6) return visits to all food qualities, in contrast to 33% of ants in autumn under low starvation.Fitting the empirical findings into an agent-based model revealed that even a tendency of ants to memorise routes to high quality food sources faster can result in ecologically sensible colony-level behaviour. Low motivation colonies are also choosier, due to increasing sensitivity to food quality.Significance statementCollective decisions of insects are often achieved via communication and/or other interactions between individuals. However, animals can also make collective decisions in the absence of communication.We show that foraging motivation and food quality can affect both route memory and the likelihood to return to the food source and thus mediate selective food exploitation. An agent-based model, implemented with our empirical findings, demonstrates that, at the collective level, even small differences in learning lead to ecologically sensible behaviour: mildly starved colonies are selective for high quality food while highly starved colonies exploit all food sources equally.We therefore suggest that non-interactive factors such as individual learning and the foraging motivation of a colony can mediate or even drive group level behaviour. Instead of accounting collective behaviour exclusively to social interactions, possible contributing individual processes should also be considered.

Risk Assessment of Sulphite Exposure through Foods Among Adolescents of Delhi (India)

2019 ◽  
Vol 15 (7) ◽  
pp. 685-693
Author(s):  
Arushi Jain ◽  
Pulkit Mathur
Keyword(s):  
Risk Assessment ◽  
Food Intake ◽  
Daily Intake ◽  
Food Sources ◽  
Acceptable Daily Intake ◽  
Food Record ◽  
Government Schools ◽  
Adverse Health Effects ◽  
Food Items ◽  
Permissible Levels

Background: Sulphites added as preservatives in food have been associated with adverse health effects in humans. Objective: The present study was designed with an objective of assessing the risk of sulphite exposure through food in adolescents (12-16 years old) of Delhi, India. Methods: A total of 1030 adolescents selected from four private and four government schools of Delhi, were asked to record their food intake using a 24 hour food record, repeated on three days, for assessing exposure to sulphites. The risk was assessed using six different scenarios of exposure. Results: The actual intake for sulphites for average consumers was 0.15 ± 0.13 mg / kg b.w. / day which was 21.4% of acceptable daily intake (ADI). For high consumers (P95), it was 65% of the ADI. However, for 2 respondents, the actual intake exceeded the ADI. The major food contributors to sulphite intake were beverage concentrates (46%), ready to serve beverages (22%) followed by miscellaneous food items (16%), mainly ice creams and snowballs. Estimation of sulphite intake using different exposure scenarios revealed that for certain scenarios where the highest reported sulphite level or maximum permissible levels were considered for calculation, the high consumers exceeded the ADI, though, for average consumers, intake was well below the ADI. Conclusion: Actual intake of sulphite for average consumers was well below the ADI but for high consumers was approaching the ADI. People with sulphite sensitivity need to be aware of hidden food sources of sulphites.

scholarly journals The magnitude and colour of noise in genetic negative feedback systems

2012 ◽  
Vol 40 (15) ◽  
pp. 7084-7095 ◽  
Author(s):  
Margaritis Voliotis ◽  
Clive G. Bowsher
Keyword(s):  
Negative Feedback ◽  
Feedback Systems

RED JUNGLE FOWL HAVE MORE CONTRAFREELOADING THAN WHITE LEGHORN LAYERS: EFFECT OF FOOD DEPRIVATION AND CONSEQUENCES FOR INFORMATION GAIN

Behaviour ◽  
2002 ◽  
Vol 139 (9) ◽  
pp. 1195-1209 ◽  
Author(s):  
Per Jensen ◽  
Karin Schütz ◽  
Christina Lindqvist
Keyword(s):  
Food Deprivation ◽  
Food Source ◽  
Information Gain ◽  
High Gain ◽  
Alternative Food ◽  
Food Sources ◽  
Production Environment ◽  
White Leghorn ◽  
Wood Shavings ◽  
Red Jungle Fowl

AbstractContrafreeloading (CFL), i.e. choosing food which requires work over free food, occurs at a higher rate in red jungle fowl (Gallus gallus) compared to White Leghorn layers. We examined whether this difference between breeds was altered by food deprivation and whether it affected the information gained about alternative food sources. In a first experiment, twenty birds of each breed were deprived for zero, three and six hours and then allowed a choice of feeding from freely available food or food mixed with wood shavings. In both breeds, CFL tended to decrease after deprivation, but jungle fowl consistently showed more CFL than Leghorns also after food deprivation. This shows that differences in CFL between breeds were not altered by food deprivation, and the larger CFL in jungle fowl may represent a genetically based difference in feeding strategy. In a second experiment, we examined whether the differences in CFL affected how the birds acquired information about alternative food sites of different quality. Twenty birds of each breed were allowed to forage during three 10 min sessions in a four armed maze, where symbols in each end of the arms indicated the location of four different quality food sources; 'high gain' (freely available food), 'medium gain' (70% food, 30% wood shavings), 'low gain' (30% food), and 'no gain' (100% wood shavings). Each bird was then tested in the same maze when the 'high gain' food source and its symbol had been removed, and the other three sources contained only the symbols and wood shavings. Jungle fowl chose the symbol indicating the best available food source significantly more often than the Leghorns. The results indicate that Leghorn gain less information during foraging, which may have consequences for their adaptation capacity in a production environment. This could either be a consequence of Leghorns showing less CFL, or a generally impaired learning capacity of Leghorns compared to jungle fowl.

scholarly journals Negative feedback in ants: crowding results in less trail pheromone deposition

2013 ◽  
Vol 10 (81) ◽  
pp. 20121009 ◽  
Author(s):  
Tomer J. Czaczkes ◽  
Christoph Grüter ◽  
Francis L. W. Ratnieks
Keyword(s):  
Negative Feedback ◽  
Trail Pheromone ◽  
Distribution Networks ◽  
Feedback Mechanism ◽  
Lasius Niger ◽  
Feedback Signal ◽  
Control Mechanisms ◽  
Negative Feedback Mechanism ◽  
Self Organized ◽  
Fold Reduction

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-organized negative feedback mechanism, based on local information, which downregulates the production of recruitment signals in crowded parts of a network by Lasius niger ants. We controlled crowding by manipulating trail width and the number of ants on a trail, and observed a 5.6-fold reduction in the number of ants depositing trail pheromone from least to most crowded conditions. We also simulated crowding by placing glass beads covered in nest-mate cuticular hydrocarbons on the trail. After 10 bead encounters over 20 cm, forager ants were 45 per cent less likely to deposit pheromone. The mechanism of negative feedback reported here is unusual in that it acts by downregulating the production of a positive feedback signal, rather than by direct inhibition or the production of an inhibitory signal.

scholarly journals The contribution of the Canary Island date palm (Phoenix canariensis) to the winter diet of frugivores in novel ecosystems

2019 ◽  
Vol 5 (1) ◽  
pp. 27-37 ◽  
Author(s):  
Dirk HR Spennemann
Keyword(s):  
Urban Areas ◽  
Canary Island ◽  
Food Source ◽  
Date Palm ◽  
Food Sources ◽  
Novel Ecosystems ◽  
Date Palms ◽  
Phoenix Canariensis ◽  
Winter Diet ◽  
Native Foods

Abstract With the increasing expansion in urban areas, many species have adapted to utilising horticulturally used plants as alternate or augmentary food sources, in particular, during winter – when native foods are largely absent. Ornamental palms, particularly Canary Island Date Palms, fruit continuously during most of the year and thus provide a stable food supply. Based on observational, metric and bio-chemical data, this paper examines the role Canary Island Date Palms can and do play in the nutrition of frugivorous animals, in particular, for birds. It demonstrates that with its nearly year-round provisioning of drupes, the palm plays a major role as a ‘staple’ and backup food source for several species.

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