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James C Nieh - One of the best experts on this subject based on the ideXlab platform.
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honey bee inhibitory signaling is tuned to threat severity and can act as a colony alarm signal
PLOS Biology, 2016Co-Authors: Shihao Dong, Xinyu Li, Chao Wang, Jianjun Li, James C NiehAbstract:Alarm communication is a key adaptation that helps social groups resist predation and rally defenses. In Asia, the world’s largest hornet, Vespa mandarinia, and the smaller hornet, Vespa velutina, prey upon Foragers and nests of the Asian honey bee, Apis cerana. We attacked Foragers and colony nest entrances with these predators and provide the first evidence, in social insects, of an alarm signal that encodes graded danger and attack context. We show that, like Apis mellifera, A. cerana possesses a vibrational “stop signal,” which can be triggered by predator attacks upon Foragers and inhibits waggle dancing. Large hornet attacks were more dangerous and resulted in higher bee mortality. Per attack at the colony level, large hornets elicited more stop signals than small hornets. Unexpectedly, stop signals elicited by large hornets (SS large hornet) had a significantly higher vibrational fundamental frequency than those elicited by small hornets (SS small hornet) and were more effective at inhibiting waggle dancing. Stop signals resulting from attacks upon the nest entrance (SS nest) were produced by Foragers and guards and were significantly longer in pulse duration than stop signals elicited by attacks upon Foragers (SS Forager). Unlike SS Forager, SS nest were targeted at dancing and non-dancing Foragers and had the common effect, tuned to hornet threat level, of inhibiting bee departures from the safe interior of the nest. Meanwhile, nest defenders were triggered by the bee alarm pheromone and live hornet presence to heat-ball the hornet. In A. cerana, sophisticated recruitment communication that encodes food location, the waggle dance, is therefore matched with an inhibitory/alarm signal that encodes information about the context of danger and its threat level.
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Long distance foraging and recruitment by a stingless bee, Melipona mandacaia
Apidologie, 2009Co-Authors: Brunno Kuhn-neto, Felipe A.l. Contrera, Marina S. Castro, James C NiehAbstract:Body size is hypothesized to play a major role in animal foraging, particularly in pollinators. In general, species with larger bodies forage over greater distances. Studies have found support for this body size-foraging range hypothesis across a wide variety of pollinator species, but have not investigated the possibility that this effect also applies within a pollinator species. We trained Foragers of the stingless bee Melipona mandacaia to feeders in their native habitat under natural conditions, and found that larger Foragers forage at and recruit to significantly greater distances than smaller Foragers. The maximum foraging and recruitment distances are significantly greater (by 24% and 48% respectively) for larger as compared to smaller Foragers. We also provide the first direct evidence that stingless bees can forage in their native habitat at distances up to 2.1 km and recruit over 1 km from their nest, recruiting more than 230% farther than previously reported for any stingless bee feeder experiments. Natural size variation among colonies within the same species may play a role in foraging range, and could thus influence plant gene flow and population structure.
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bumble bee olfactory information flow and contact based foraging activation
Insectes Sociaux, 2008Co-Authors: M A Renner, James C NiehAbstract:Nestmate foraging activation and interspecific variation in foraging activation is poorly understood in bumble bees, as compared to honey bees and stingless bees. We therefore investigated olfactory information flow and foraging activation in the New World bumble bee species, Bombus impatiens. We (1) tested the ability of Foragers to associate Forager-deposited odor marks with rewarding food, (2) determined whether potential Foragers will seek out the food odor brought back by a successful Forager, and (3) examined the role of intranidal tactile contacts in foraging activation. Bees learned to associate Forager-deposited odor marks with rewarding food. They were significantly more attracted to an empty previously rewarding feeder presented at a random position within an array of eight previously non-rewarding feeders. However, Foragers did not exhibit overall odor specificity for short-term, daily floral shifts. For two out of three tested scents, activated Foragers did not significantly prefer the feeder providing the same scent as that brought back by a successful Forager. Finally, bees contacted by the successful Forager inside the nest were significantly more likely to leave the nest to forage (38.6% increase in attempts to feed from empty feeders) than were non-contacted bees. This is the first demonstration that tactile contact, a hypothesized evolutionary basal communication mechanism in the social corbiculate bees, is involved in bumble bee foraging activation.
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multi source odor marking of food by a stingless bee melipona mandacaia
Behavioral Ecology and Sociobiology, 2003Co-Authors: James C Nieh, Santiago Ramrez, Paulo NogueiranetoAbstract:Social bees can deposit specialized glandular secretions, or signals, that allow Foragers to revisit rewarding and to avoid unrewarding food sources. However, it is not known if bees can orient towards olfactory cues such as excreta deposited near food sources. We report that Melipona mandacaia Foragers (stingless bees) deposit an odor cue, anal droplets, and a previously undescribed ventro-abdominal odor on food sources. Surprisingly, Foragers deposited attractive odor marks on good food sources to which they recruited and on poor food sources to which they did not recruit. Foragers left the most anal droplets on dilute food sources to which they did not recruit (1.25-M sucrose solution), yet returning Foragers were attracted to anal droplets obtained on poor food sources and presented in bioassays. Foragers were attracted to ventro-abdominal odors obtained on good food sources (2.5-M sucrose solution). Chemical extractions suggest that odor marks contain attractive polar compounds. We also provide the first detailed description of Forager waggling and spinning behavior on poor and good food sources. Waggling may be a method of dispersing anal droplets and spinning may help Foragers learn local landmarks.
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the food recruitment dance of the stingless bee melipona panamica
Behavioral Ecology and Sociobiology, 1998Co-Authors: James C NiehAbstract:Foragers of the stingless bee Meliponapanamica can communicate the location of a good food source to nestmates and evidently communicate part of this information inside the nest. However there is no careful description of within-nest recruitment behavior for this species or for any other stingless bee. Therefore the goal of this paper is to provide a detailed description of the behaviors of recruiting M. panamica Foragers within the nest. A recruiting Forager enters the nest, begins producing pulsed sounds as food-unloading bees collect her food (unloading phase), and then performs a dance by rapidly executing clockwise and counterclockwise turns while continuing to produce sound pulses (dance phase). To investigate whether directional information is encoded in the dance, I alternately recorded the behavior of Foragers trained to two food sources, each 175 m from the colony but in opposite directions (north and south). I examined the following parameters and found no differences between the dances of Foragers feeding in opposite directions: (1) order of clockwise and counterclockwise turns, (2) turn direction, (3) angular start position, (4) angular stop position, (5) turn magnitude, and (6) turn angular velocity. Foragers recruiting for a rich food source (2.5 M) initially unloaded food with their bodies oriented 180° from the entrance. They began turns at random orientations, but tended to end these turns facing the nest entrance (0°). Dancers for poor food sources (1.0 M sucrose solution) turned at significantly lower velocities than dancers for good food sources (2.5 M sucrose solution), and exhibited random initial, start-turn, and stop-turn orientations. Throughout her stay inside the nest, the recruiting Forager produced sounds. During sound production, her folded wings vibrated dorsoventrally over her abdomen and she attracted the attention of follower bees who positioned their antennae closely around her body. Foragers recruiting for 1.0 M and 2.5 M food sources attracted the same number of food-unloading bees, but 1.0 M recruiters attracted significantly fewer followers around their abdomens.
Thomas D Seeley - One of the best experts on this subject based on the ideXlab platform.
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honey bees use social information in waggle dances more fully when foraging errors are more costly
Behavioral Ecology, 2012Co-Authors: Margaret K Wray, Barrett A Klein, Thomas D SeeleyAbstract:Social animals can obtain valuable information from group members, but sometimes experience conflicts between this social information and personal information obtained through their own experience. Experienced honey bee Foragers (Apis mellifera) have personal information about familiar food sources, and can also obtain social information by following waggle dances. However, it is unclear whether temporarily unemployed Foragers whose visits to a food source have been interrupted make full use of social information from dancers or rely primarily on their own personal information to determine whether their familiar food source is active again. We hypothesized that experienced Foragers should pay more attention to the social information in waggle dances when foraging errors that can arise from ignoring social information are more costly. We manipulated the cost of mistakenly flying to a familiar but unprofitable food source by training bees to visit feeders that were either close (100 m) or far (1000 m) from the hive and found that temporarily unemployed Foragers who had been trained to forage at more distant feeders were more likely to pay attention to social information about food source location. Our findings demonstrate that experienced Forager bees can flexibly alter the extent to which they rely on social, as opposed to personal, information and are more likely to fully utilize social information from dancers when foraging errors are more costly. Key words: Apis mellifera, communication, dance language, reactivation, social information, waggle dance. [Behav Ecol]
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the use of waggle dance information by honey bees throughout their foraging careers
Behavioral Ecology and Sociobiology, 2005Co-Authors: Jacobus C. Biesmeijer, Thomas D SeeleyAbstract:We studied the extent to which worker honey bees acquire information from waggle dances throughout their careers as Foragers. Small groups of Foragers were monitored from time of orientation flights to time of death and all in-hive behaviors relating to foraging were recorded. In the context of a novice Forager finding her first food source, 60% of the bees relied, at least in part, on acquiring information from waggle dances (being recruited) rather than searching independently (scouting). In the context of an experienced Forager whose foraging has been interrupted, 37% of the time the bees resumed foraging by following waggle dances (being reactivated) rather than examining the food source on their own (inspecting). And in the context of an experienced Forager engaged in foraging, 17% of the time the bees initiated a foraging trip by following a waggle dance. Such dance following was observed much more often after an unsuccessful than after a successful foraging trip. Successful Foragers often followed dances just briefly, perhaps to confirm that the kind of flowers they had been visiting were still yielding forage. Overall, waggle dance following for food discovery accounted for 12–25% of all interactions with dancers (9% by novice Foragers and 3–16% by experienced Foragers) whereas dance following for reactivation and confirmation accounted for the other 75–88% (26% for reactivation and 49–62% for confirmation). We conclude that Foragers make extensive use of the waggle dance not only to start work at new, unfamiliar food sources but also to resume work at old, familiar food sources.
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the wisdom of the hive the social physiology of honey bee colonies
1995Co-Authors: Thomas D SeeleyAbstract:PART I. INTRODUCTION 1. The Issues 1.1. The Evolution of Biological Organization 1.2. The Honey Bee Colony as a Unit of Function 1.3. Analytic Scheme 2. The Honey Bee Colony 2.1. Worker Anatomy and Physiology 2.2. Worker Life History 2.3. Nest Architecture 2.4. The Annual Cycle of a Colony 2.5. Communication about Food Sources 2.6. Food Collection and Honey Production 3. The Foraging Abilities of a Colony 3.1. Exploiting Food Sources over a Vast Region around the Hive 3.2. Surveying the Countryside for Rich Food Sources 3.3. Responding Quickly to Valuable Discoveries 3.4. Choosing among Food Sources 3.5. Adjusting Selectivity in Relation to Forage Abundance 3.6. Regulating Comb Construction 3.7. Regulating Pollen Collection 3.8. Regulating Water Collection Summary PART II. EXPERIMENTAL ANALYSIS 4. Methods and Equipment 4.1. The Observation Hive 4.2. The Hut for the Observation Hive 4.3. The Bees 4.4. Sugar Water Feeders 4.5. Labeling Bees 4.6. Measuring the Total Number of Bees Visiting a Feeder 4.7. Observing Bees of Known Age 4.8. Recording the Behavior of Bees in the Hive 4.9. The Scale Hive 4.10. Censusing a Colony 5. Allocation of Labor among Forage Sites How a Colony Acquires Information about Food Sources 5.1. Which Bees Gather the Information? 5.2. Which Information Is Shared? 5.3. Where Information Is Shared inside the Hive 5.4. The Coding of Information about Profitability 5.5. The Bees' Criterion of Profitability 5.6. The Relationship between Nectar-Source 5.7. The Adaptive Tuning of Dance Thresholds 5.8. How a Forager Determines the Profitability of a Nectar Source Summary How a Colony Acts on Information about Food Sources 5.9. Employed Foragers versus Unemployed Foragers 5.10. How Unemployed Foragers Read the Information on the Dance Floor? 5.11.
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honey bee Foragers as sensory units of their colonies
Behavioral Ecology and Sociobiology, 1994Co-Authors: Thomas D SeeleyAbstract:Forager honey bees function not only as gatherers of food for their colonies, but also as sensory units shaped by natural selection to gather information regarding the location and profitability of forage sites. They transmit this information to colony members by means of waggle dances. To investigate the way bees transduce the stimulus of nectar-source profitability into the response of number of waggle runs, I performed experiments in which bees were stimulated with a sucrose solution feeder of known profitability and their dance responses were videorecorded. The results suggest that several attributes of this transduction process are adaptations to enhance a bee's effectiveness in reporting on a forage site. (1) Bees register the profitability of a nectar source not by sensing the energy gain per foraging trip or the rate of energy gain per trip, but evidently by sensing the energetic efficiency of their foraging. Perhaps this criterion of nectar-source profitability has been favored by natural selection because the foraging gains of honey bees are typically limited by energy expenditure rather than time availability. (2) There is a linear relationship between the stimulus of energetic efficiency of foraging and the response of number of waggle runs per dance. Such a simple stimulus-response function appears adequate because the range of suprathreshold stimuli (max/min ratio of about 10) is far smaller than the range of responses (max/min ratio of about 100). Although all bees show a linear stimulus-response function, there are large differences among individuals in both the response threshold and the slope of the stimulus-response function. This variation gives the colony a broader dynamic range in responding to food sources than if all bees had identical thresholds of dance response. (3) There is little or no adaptation in the dance response to a strong stimulus (tonic response). Thus each dancing bee reports on the current level of profitability of her forage site rather than the changes in its profitability. This seems appropriate since presumably it is the current profitability of a forage site, not the change in its profitability, which determines a site's attractiveness to other bees. (4) The level of forage-site quality that is the threshold for dancing is tuned by the bees in relation to forage availability. Bees operate with a lower dance threshold when forage is sparse than when it is abundant. Thus a colony utilizes input about a wide range of forage sites when food is scarce, but filters out input about low-reward sites when food is plentiful. (5) A dancing bee does not present her information in one spot within the hive but instead distributes it over much of the dance floor. Consequently, the dances for different forage sites are mixed together on the dance floor. This helps each bee following the dances to take a random sample of the dance information, which is appropriate for the foraging strategy of a honey bee colony since it is evidently designed to allocate Foragers among forage sites in proportion to their profitability.
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collective decision making in honey bees how colonies choose among nectar sources
Behavioral Ecology and Sociobiology, 1991Co-Authors: Thomas D Seeley, Scott Camazine, James SneydAbstract:A honey bee colony can skillfully choose among nectar sources. It will selectively exploit the most profitable source in an array and will rapidly shift its foraging efforts following changes in the array. How does this colony-level ability emerge from the behavior of individual bees? The answer lies in understanding how bees modulate their colony's rates of recruitment and abandonment for nectar sources in accordance with the profitability of each source. A Forager modulates its behavior in relation to nectar source profitability: as profitability increases, the tempo of foraging increases, the intensity of dancing increases, and the probability of abandoning the source decreases. How does a Forager assess the profitability of its nectar source? Bees accomplish this without making comparisons among nectar sources. Neither do the Foragers compare different nectar sources to determine the relative profitability of any one source, nor do the food storers compare different nectar loads and indicate the relative profitability of each load to the Foragers. Instead, each Forager knows only about its particular nectar source and independently calculates the absolute profitability of its source. Even though each of a colony's Foragers operates with extremely limited information about the colony's food sources, together they will generate a coherent colonylevel response to different food sources in which better ones are heavily exploited and poorer ones are abandoned. This is shown by a computer simulation of nectar-source selection by a colony in which Foragers behave as described above. Nectar-source selection by honey bee colonies is a process of natural selection among alternative nectar sources as Foragers from more profitable sources “survive” (continue visiting their source) longer and “reproduce” (recruit other Foragers) better than do Foragers from less profitable sources. Hence this colonial decision-making is based on decentralized control. We suggest that honey bee colonies possess decentralized decision-making because it combines effectiveness with simplicity of communication and computation within a colony.
Jacobus C. Biesmeijer - One of the best experts on this subject based on the ideXlab platform.
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the use of waggle dance information by honey bees throughout their foraging careers
Behavioral Ecology and Sociobiology, 2005Co-Authors: Jacobus C. Biesmeijer, Thomas D SeeleyAbstract:We studied the extent to which worker honey bees acquire information from waggle dances throughout their careers as Foragers. Small groups of Foragers were monitored from time of orientation flights to time of death and all in-hive behaviors relating to foraging were recorded. In the context of a novice Forager finding her first food source, 60% of the bees relied, at least in part, on acquiring information from waggle dances (being recruited) rather than searching independently (scouting). In the context of an experienced Forager whose foraging has been interrupted, 37% of the time the bees resumed foraging by following waggle dances (being reactivated) rather than examining the food source on their own (inspecting). And in the context of an experienced Forager engaged in foraging, 17% of the time the bees initiated a foraging trip by following a waggle dance. Such dance following was observed much more often after an unsuccessful than after a successful foraging trip. Successful Foragers often followed dances just briefly, perhaps to confirm that the kind of flowers they had been visiting were still yielding forage. Overall, waggle dance following for food discovery accounted for 12–25% of all interactions with dancers (9% by novice Foragers and 3–16% by experienced Foragers) whereas dance following for reactivation and confirmation accounted for the other 75–88% (26% for reactivation and 49–62% for confirmation). We conclude that Foragers make extensive use of the waggle dance not only to start work at new, unfamiliar food sources but also to resume work at old, familiar food sources.
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exploration and exploitation of food sources by social insect colonies a revision of the scout recruit concept
Behavioral Ecology and Sociobiology, 2001Co-Authors: Jacobus C. Biesmeijer, Han De VriesAbstract:Social insect colonies need to explore and exploit multiple food sources simultaneously and efficiently. At the individual level, this colony-level behaviour has been thought to be taken care of by two types of individual: scouts that independently search for food, and recruits that are directed by nest mates to a food source. However, recent analyses show that this strict division of labour between scouts and recruits is untenable. Therefore, a modified concept is presented here that comprises the possible behavioural states of an individual Forager (novice Forager, scout, recruit, employed Forager, unemployed experienced Forager, inspector and reactivated Forager) and the transitions between them. The available empirical data are reviewed in the light of both the old and the new concept, and probabilities for the different transitions are derived for the case of the honey-bee. The modified concept distinguishes three types of Foragers that may be involved in the exploration behaviour of the colony: novice bees that become scouts, unemployed experienced bees that scout, and lost recruits, i.e. bees that discover a food source other than the one to which they were directed to by their nest mates. An advantage of the modified concept is that it allows for a better comparison of studies investigating the different roles performed by social insect Foragers during their individual foraging histories.
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the response of the stingless bee melipona beecheii to experimental pollen stress worker loss and different levels of information input
Journal of Apicultural Research, 1999Co-Authors: Jacobus C. Biesmeijer, M Born, S Lukacs, Marinus J. SommeijerAbstract:SUMMARYIn honey bees, both the allocation of Foragers to pollen collecting and the behaviour of the pollen Foragers depends on the colony's need for pollen, the mortality rate of Foragers and the input of information regarding pollen availability in the field. The response of stingless bees to these factors is not known. Therefore, we studied the response of Melipona beecheii to experimental pollen deprivation, worker loss and controlled information input. Following pollen stress M. beecheii did not increase its Forager force, but allocated more Foragers to pollen foraging. There was an indication that individual foraging was intensified. During the first 10 days after the reduction of the pollen reserve, pollen availability in the field was low and pollen foraging almost stopped. The increase in pollen foraging occurred after these 10 days. M. beecheii did not respond to daily variation in worker mortality or experimentally induced 50% worker loss. Behaviour of pollen Foragers was related to previous day...
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The role of internal and external information in foraging decisions of Melipona workers (Hymenoptera : Meliponinae)
Behavioral Ecology and Sociobiology, 1998Co-Authors: Jacobus C. Biesmeijer, Mark G. L. Van Nieuwstadt, Saskia Lukács, Marinus J. SommeijerAbstract:Social insect Foragers have to make foraging decisions based on information that may come from two different sources: information learned and memorised through their own experience (“internal” information) and information communicated by nest mates or directly obtained from their environment (“external” information). The role of these sources of information in decision-making by Foragers was studied observationally and experimentally in stingless bees of the genus Melipona. Once a Melipona Forager had started its food-collecting career, its decisions to initiate, continue or stop its daily collecting activity were mainly based upon previous experience (activity on previous days, the time at which foraging was initiated the day(s) before, and, during the day, the success of the last foraging flights) and mediated through direct interaction with the food source (load size harvested and time to collect a load). External information provided by returning Foragers advanced the start of foraging of experienced bees. Most inexperienced bees initiated their foraging day after successful Foragers had returned to the hive. The start of foraging by other inexperienced bees was stimulated by high waste-removal activity of nest mates. By experimentally controlling the entries of Foragers (hence external information input) it was shown that very low levels of external information input had large effect on the departure of experienced Foragers. After the return of a single successful Forager, or five Foragers together, the rate of Forager exits increased dramatically for 15 min. Only the first and second entry events had large effect; later entries influenced Forager exit patterns only slightly. The results show that Melipona Foragers make decisions based upon their own experience and that communication stimulates these Foragers if it concerns the previously visited source. We discuss the organisation of individual foraging in Melipona and Apis mellifera and are led to the conclusion that these species behave very similarly and that an information-integration model (derived from Fig. 1) could be a starting point for future research on social insect foraging.
Marinus J. Sommeijer - One of the best experts on this subject based on the ideXlab platform.
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the response of the stingless bee melipona beecheii to experimental pollen stress worker loss and different levels of information input
Journal of Apicultural Research, 1999Co-Authors: Jacobus C. Biesmeijer, M Born, S Lukacs, Marinus J. SommeijerAbstract:SUMMARYIn honey bees, both the allocation of Foragers to pollen collecting and the behaviour of the pollen Foragers depends on the colony's need for pollen, the mortality rate of Foragers and the input of information regarding pollen availability in the field. The response of stingless bees to these factors is not known. Therefore, we studied the response of Melipona beecheii to experimental pollen deprivation, worker loss and controlled information input. Following pollen stress M. beecheii did not increase its Forager force, but allocated more Foragers to pollen foraging. There was an indication that individual foraging was intensified. During the first 10 days after the reduction of the pollen reserve, pollen availability in the field was low and pollen foraging almost stopped. The increase in pollen foraging occurred after these 10 days. M. beecheii did not respond to daily variation in worker mortality or experimentally induced 50% worker loss. Behaviour of pollen Foragers was related to previous day...
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The role of internal and external information in foraging decisions of Melipona workers (Hymenoptera : Meliponinae)
Behavioral Ecology and Sociobiology, 1998Co-Authors: Jacobus C. Biesmeijer, Mark G. L. Van Nieuwstadt, Saskia Lukács, Marinus J. SommeijerAbstract:Social insect Foragers have to make foraging decisions based on information that may come from two different sources: information learned and memorised through their own experience (“internal” information) and information communicated by nest mates or directly obtained from their environment (“external” information). The role of these sources of information in decision-making by Foragers was studied observationally and experimentally in stingless bees of the genus Melipona. Once a Melipona Forager had started its food-collecting career, its decisions to initiate, continue or stop its daily collecting activity were mainly based upon previous experience (activity on previous days, the time at which foraging was initiated the day(s) before, and, during the day, the success of the last foraging flights) and mediated through direct interaction with the food source (load size harvested and time to collect a load). External information provided by returning Foragers advanced the start of foraging of experienced bees. Most inexperienced bees initiated their foraging day after successful Foragers had returned to the hive. The start of foraging by other inexperienced bees was stimulated by high waste-removal activity of nest mates. By experimentally controlling the entries of Foragers (hence external information input) it was shown that very low levels of external information input had large effect on the departure of experienced Foragers. After the return of a single successful Forager, or five Foragers together, the rate of Forager exits increased dramatically for 15 min. Only the first and second entry events had large effect; later entries influenced Forager exit patterns only slightly. The results show that Melipona Foragers make decisions based upon their own experience and that communication stimulates these Foragers if it concerns the previously visited source. We discuss the organisation of individual foraging in Melipona and Apis mellifera and are led to the conclusion that these species behave very similarly and that an information-integration model (derived from Fig. 1) could be a starting point for future research on social insect foraging.
Deborah M Gordon - One of the best experts on this subject based on the ideXlab platform.
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effect of interactions between harvester ants on Forager decisions
Frontiers in Ecology and Evolution, 2016Co-Authors: Jacob D Davidson, Deborah M Gordon, Sam P Crow, Roxana P Araucoaliaga, Mark S GoldmanAbstract:Harvester ant colonies adjust their foraging activity to day-to-day changes in food availability and hour-to-hour changes in environmental conditions. This collective behavior is regulated through interactions, in the form of brief antennal contacts, between outgoing Foragers and returning Foragers with food. Here we consider how an ant, waiting in the entrance chamber just inside the nest entrance, uses its accumulated experience of interactions to decide whether to leave the nest to forage. Using videos of field observations, we tracked the interactions and foraging decisions of ants in the entrance chamber. Outgoing Foragers tended to interact with returning Foragers at higher rates than ants that returned to the deeper nest and did not forage. To provide a mechanistic framework for interpreting these results, we develop a decision model in which ants make decisions based upon a noisy accumulation of individual contacts with returning Foragers. The model can reproduce core trends and realistic distributions for individual ant interaction statistics, and suggests possible mechanisms by which foraging activity may be regulated at an individual ant level.
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interactions increase Forager availability and activity in harvester ants
PLOS ONE, 2015Co-Authors: Evlyn Pless, Jovel Queirolo, Noa Pinterwollman, Sam P Crow, Kelsey R Allen, Maya B Mathur, Deborah M GordonAbstract:Social insect colonies use interactions among workers to regulate collective behavior. Harvester ant Foragers interact in a chamber just inside the nest entrance, here called the 'entrance chamber'. Previous studies of the activation of Foragers in red harvester ants show that an outgoing Forager inside the nest experiences an increase in brief antennal contacts before it leaves the nest to forage. Here we compare the interaction rate experienced by Foragers that left the nest and ants that did not. We found that ants in the entrance chamber that leave the nest to forage experienced more interactions than ants that descend to the deeper nest without foraging. Additionally, we found that the availability of Foragers in the entrance chamber is associated with the rate of Forager return. An increase in the rate of Forager return leads to an increase in the rate at which ants descend to the deeper nest, which then stimulates more ants to ascend into the entrance chamber. Thus a higher rate of Forager return leads to more available Foragers in the entrance chamber. The highest density of interactions occurs near the nest entrance and the entrances of the tunnels from the entrance chamber to the deeper nest. Local interactions with returning Foragers regulate both the activation of waiting Foragers and the number of Foragers available to be activated.
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harvester ants use interactions to regulate Forager activation and availability
Animal Behaviour, 2013Co-Authors: Noa Pinterwollman, Susan Holmes, Jovel Queirolo, Ashwin Bala, Andrew Merrell, Martin C Stumpe, Deborah M GordonAbstract:Social groups balance flexibility and robustness in their collective response to environmental changes using feedback between behavioural processes that operate at different timescales. Here we examine how behavioural processes operating at two timescales regulate the foraging activity of colonies of the harvester ant, Pogonomyrmex barbatus, allowing them to balance their response to food availability and predation. Previous work showed that the rate at which Foragers return to the nest with food influences the rate at which Foragers leave the nest. To investigate how interactions inside the nest link the rates of returning and outgoing Foragers, we observed outgoing Foragers inside the nest in field colonies using a novel observation method. We found that the interaction rate experienced by outgoing Foragers inside the nest corresponded to Forager return rate, and that the interactions of outgoing Foragers were spatially clustered. Activation of a Forager occurred on the timescale of seconds: a Forager left the nest 3–8 s after a substantial increase in interactions with returning Foragers. The availability of outgoing Foragers to become activated was adjusted on the timescale of minutes: when Forager return was interrupted for more than 4–5 min, available Foragers waiting near the nest entrance went deeper into the nest. Thus, Forager activation and Forager availability both increased with the rate at which Foragers returned to the nest. This process was checked by negative feedback between Forager activation and Forager availability. Regulation of foraging activation on the timescale of seconds provides flexibility in response to fluctuations in food abundance, whereas regulation of Forager availability on the timescale of minutes provides robustness in response to sustained disturbance such as predation.
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the regulation of ant colony foraging activity without spatial information
PLOS Computational Biology, 2012Co-Authors: Balaji Prabhakar, Katherine N Dektar, Deborah M GordonAbstract:Many dynamical networks, such as the ones that produce the collective behavior of social insects, operate without any central control, instead arising from local interactions among individuals. A well-studied example is the formation of recruitment trails in ant colonies, but many ant species do not use pheromone trails. We present a model of the regulation of foraging by harvester ant (Pogonomyrmex barbatus) colonies. This species forages for scattered seeds that one ant can retrieve on its own, so there is no need for spatial information such as pheromone trails that lead ants to specific locations. Previous work shows that colony foraging activity, the rate at which ants go out to search individually for seeds, is regulated in response to current food availability throughout the colony's foraging area. Ants use the rate of brief antennal contacts inside the nest between Foragers returning with food and outgoing Foragers available to leave the nest on the next foraging trip. Here we present a feedback-based algorithm that captures the main features of data from field experiments in which the rate of returning Foragers was manipulated. The algorithm draws on our finding that the distribution of intervals between successive ants returning to the nest is a Poisson process. We fitted the parameter that estimates the effect of each returning Forager on the rate at which outgoing Foragers leave the nest. We found that correlations between observed rates of returning Foragers and simulated rates of outgoing Foragers, using our model, were similar to those in the data. Our simple stochastic model shows how the regulation of ant colony foraging can operate without spatial information, describing a process at the level of individual ants that predicts the overall foraging activity of the colony.
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how site fidelity leads to individual differences in the foraging activity of harvester ants
Behavioral Ecology, 2009Co-Authors: Blair D Beverly, H Mclendon, Serban Nacu, Susan Holmes, Deborah M GordonAbstract:We examined how differences in activity among individual Foragers of the red harvester ant, Pogonomyrmex barbatus, could arise from site fidelity. Using observations of individually marked Foragers, we found that each day most Foragers made a few foraging trips, whereas only a few Foragers made many trips. To determine whether only particular individuals are capable of high foraging activity, we removed the Foragers that made the most foraging trips on 1 day and examined the frequency distribution of foraging the subsequent day. The most active Foragers were replaced by other individuals. We then examined site fidelity of Foragers. Though foraging trails extend up to 20 m from the nest, observations of marked individuals showed that on successive trips, a Forager returns to sites within about 0.5 m. Foraging trip duration depended on search time and not on the distance from the nest of the final destination. Thus, the more food available, the shorter the search time and the shorter the trip. Because Foragers return to the same site over and over within a day, a Forager making many short trips to a high-quality patch can make more foraging trips per day. Thus, variation in patch quality, rather than individual variation in foraging ability, could produce the observed distribution of trip number. These results show that regulation of foraging in harvester ants does not require any individuals to show others a particular location with abundant food. Instead, a decentralized system of interactions tunes the numbers foraging to current food availability. Copyright 2009, Oxford University Press.