scholarly journals Mechanisms determining relationships between feeding group size and foraging success in food patch use by Japanese macaques (Macaca fuscata)

Behaviour ◽  
2010 ◽  
Vol 147 (11) ◽  
pp. 1481-1500 ◽  
Author(s):  
Nobuko Kazahari ◽  
Naoki Agetsuma
Keyword(s):  
Group Size ◽  
Feeding Rate ◽  
Japanese Macaques ◽  
Feeding Competition ◽  
Foraging Success ◽  
Feeding Groups ◽  
Social Monitoring ◽  
Monitoring Frequency ◽  
Feeding Group ◽  
Group Members

AbstractWe evaluated the effects of social monitoring and feeding competition on foraging success in relation to the feeding group size of wild Japanese macaques (Macaca fuscata). Social monitoring is visual scanning by group members that assists them in following their own group. Individuals in smaller feeding groups may frequently use social monitoring while foraging, because they have an increased risk of losing their group. Therefore, social monitoring could be a cost for group-foraging animals. We made four predictions: (1) individuals in smaller feeding groups tend to abandon food patches to follow group members; (2) social monitoring frequency is higher in smaller feeding groups; (3) feeding rate decreases with increased social monitoring frequency; and (4) feeding rate initially increases with feeding group size because decreased social monitoring outweighs increased feeding competition, but after the feeding group reaches a certain size, feeding rate declines with increasing feeding group size due to the high costs of feeding competition. These predictions were supported by our results. Thus, the relationship between feeding group size and feeding rate can show three patterns (positive, neutral and negative) in response to the balance between the costs of social monitoring and feeding competition.

scholarly journals The relationships between feeding-group size and feeding rate vary from positive to negative with characteristics of food items in wild Japanese macaques (Macaca fuscata)

Behaviour ◽  
2013 ◽  
Vol 150 (2) ◽  
pp. 175-197 ◽  
Author(s):  
N. Kazahari ◽  
Y. Tsuji ◽  
N. Agetsuma
Keyword(s):  
Group Size ◽  
Feeding Rate ◽  
Group Living ◽  
Japanese Macaques ◽  
Food Density ◽  
Food Items ◽  
Feeding Group ◽  
Negative Impacts ◽  
The Relationship ◽  
Negative Relationships

To understand the costs and benefits of group-living, it is important to clarify the impacts of other individuals on foraging success. Previous studies on group-living primates have focused on the relationship between feeding-group size and feeding rate in food patches, and have exhibited inconsistent results, showing positive, neutral, or negative relationships. The relationship realized will depend on the balance of positive and negative impacts of co-feeding on feeding rate. The intensity of negative impacts (i.e., feeding competition) may vary with some characteristics of food items such as (1) patch size, (2) within-patch food density, (3) within-patch distribution pattern of food, (4) the abundance and (5) distribution pattern of within-habitat food trees, and (6) the relative energy content among available food items. Thus, the balance of positive and negative impacts of co-feeding, and ultimately the relationship between feeding-group size and feeding rate, is expected to change with characteristics of food items. In this study of wild Japanese macaques (Macaca fuscata), the relationship between feeding-group size and feeding rate, and the above six characteristics of 12 main food items were assessed over six seasons. Positive, neutral, or negative relationships between feeding-group size and feeding rate were detected among these food items. Positive relationships were consistently associated with within-patch food density; higher food density within food patches was likely to lead to positive relationships. Thus, various relationships between feeding-group size and feeding rate should be attributed to these specific characteristics of food items, which alter the degree of feeding competition.

scholarly journals Sex differences in responsiveness to begging in a cooperative mammal

2008 ◽  
Vol 4 (4) ◽  
pp. 334-337 ◽  
Author(s):  
Sinead English ◽  
Hansjoerg P Kunc ◽  
Joah R Madden ◽  
Tim H Clutton-Brock
Keyword(s):  
Sex Differences ◽  
Parental Care ◽  
Group Size ◽  
Feeding Rate ◽  
Foraging Success ◽  
Sensitive Measure ◽  
Food Items ◽  
Suricata Suricatta ◽  
Cooperatively Breeding ◽  
Consistent Tendency

In species where young are provisioned by both parents, males commonly contribute less to parental care than females, and are less responsive to variation in begging rates. Similar differences in the care of young occur among adults in cooperative breeders, but fewer studies have investigated whether these are associated with differences in responsiveness. Here, we present results from a playback experiment investigating responsiveness to begging in the meerkat ( Suricata suricatta ), a cooperatively breeding mammal. Although increased begging rate raised the feeding rate of adults of both sexes, there was no consistent tendency for females to be more responsive than males. However, when we examined changes in the proportion of food items found that were fed to pups (generosity), we found that females were more responsive than males to increased begging rate. These results can be explained in terms of sex differences in dispersal: in meerkats, females are philopatric and receive considerable benefits from investing in young, both directly, by increasing group size, and indirectly, by recruiting helpers if they inherit the breeding position. In addition, they emphasize that generosity provides a more sensitive measure of responsiveness to begging than feeding rate, as it accounts for variation in foraging success.

Does crossing the road in a group influence pedestrians’ gaze behavior?

2020 ◽  
Vol 64 (1) ◽  
pp. 1938-1942
Author(s):  
Mirjam Lanzer ◽  
Martin Baumann
Keyword(s):  
Group Size ◽  
Situational Factors ◽  
Gaze Behavior ◽  
The Road ◽  
Road Users ◽  
Gender Influence ◽  
Vulnerable Road Users ◽  
Group Members ◽  
And Gender ◽  
Group Characteristics

So far, research on pedestrians’ gaze behavior while crossing roads has mainly focused on individual pedestrians rather than groups. However, pedestrians often travel in groups especially in downtown areas. This observational study investigated how group characteristics (group size and movement of the group), situational factors (presence of traffic), and demographic variables (age and gender) influence pedestrians’ gaze behavior towards traffic during road crossing. A total of N = 197 pedestrians were observed of whom n = 24 traveled alone, n = 128 traveled in groups of two or three, and n = 45 traveled in groups of four or more. Results indicated that with increasing group size, the odds to observe traffic decreased. Diffusion of responsibility among group members might explain this effect. Finally, pedestrians’ group characteristics should be considered when developing automated vehicles that interact with vulnerable road users.

Cultured Monkeys

2008 ◽  
Vol 17 (6) ◽  
pp. 410-414 ◽  
Author(s):  
Michael A. Huffman ◽  
Charmalie A.D. Nahallage ◽  
Jean-Baptiste Leca
Keyword(s):  
Comparative Study ◽  
Systematic Study ◽  
Japanese Macaques ◽  
Mediated Learning ◽  
Research Paradigm ◽  
Animal Kingdom ◽  
Integrative Research ◽  
Group Members ◽  
Term Maintenance

Sixty years ago, the notion that animals could have culture was unthinkable to most behavioral scientists. Today, evidence for innovation, transmission, acquisition, long-term maintenance, and intergroup variation of behavior exists throughout the animal kingdom. What can the longitudinal and comparative study of monkeys handling stones tell us about how culture evolved in humans? Now in its 30th year, the systematic study of stone-handling behavior in multiple troops of Japanese macaques has shown that socially mediated learning is essential to explain the spread, persistence, and transformation of individual behavioral innovations among group members. The integrative research paradigm presented here can be applied to the study of various candidate behavioral traditions in other species.

scholarly journals Fitness of breeders in social Damaraland mole-rats is independent of group size

2021 ◽  
Author(s):  
Jack Thorley ◽  
Hanna Bensch ◽  
Kyle Finn ◽  
Tim Clutton-Brock ◽  
Markus Zöttl
Keyword(s):  
Reproductive Success ◽  
Group Size ◽  
Survival Rates ◽  
Group Living ◽  
Adult Survival ◽  
High Survival ◽  
Successful Reproduction ◽  
Related Group ◽  
Group Members ◽  
Using Data

Damaraland mole-rats (Fukomys damarensis) are usually viewed as an obligatorily group living eusocial species in which successful reproduction is dependent on reproductive altruism of closely related group members. However, the reproductive ecology of social mole-rats in their natural environment remains poorly understood and it is unclear to what extent successful reproduction is dependent on assistance from other group members. Using data from a 7-year field study of marked individuals, we show that, after dispersal from their natal group, individuals typically settled alone in new burrow systems where they enjoyed high survival rates, and often remained in good body condition for several years before finding a mate. Unlike most other eusocial or singular cooperative breeders, we found that Damaraland mole-rats reproduced successfully in pairs without helpers and experimentally formed pairs had the same reproductive success as larger established groups. Overall there was only a weak increase in reproductive success with increasing group size and no effect of group size on adult survival rates across the population. Juveniles in large groups grew faster early in life but their growth rates declined subsequently so that they eventually plateaued at a lower maximum body mass than juveniles from small groups. Taken together, our data suggest that the fitness benefits of group living to breeders are small and we suggest that extended philopatry in Damaraland mole-rats has evolved because of the high costs and constraints of dispersal rather than because of strong indirect benefits accrued through cooperative behaviour.

Group Size and Feeding Rate in Bluegills

Copeia ◽  
1984 ◽  
Vol 1984 (4) ◽  
pp. 998 ◽  
Author(s):  
Gary Mittelbach
Keyword(s):  
Group Size ◽  
Feeding Rate

scholarly journals Fight tactics in wood ants: individuals in smaller groups fight harder but die faster

2011 ◽  
Vol 278 (1722) ◽  
pp. 3243-3250 ◽  
Author(s):  
Tim P. Batchelor ◽  
Mark Briffa
Keyword(s):  
Group Size ◽  
Negative Influence ◽  
Resource Holding Potential ◽  
Attrition Rates ◽  
Formica Rufa ◽  
Wood Ants ◽  
Social Animals ◽  
Group Members ◽  
Per Capita ◽  
The Individual

When social animals engage in inter-group contests, the outcome is determined by group sizes and individual masses, which together determine group resource-holding potential (‘group RHP’). Individuals that perceive themselves as being in a group with high RHP may receive a motivational increase and increase their aggression levels. Alternatively, individuals in lower RHP groups may increase their aggression levels in an attempt to overcome the RHP deficit. We investigate how ‘group RHP’ influences agonistic tactics in red wood ants Formica rufa . Larger groups had higher total agonistic indices, but per capita agonistic indices were highest in the smallest groups, indicating that individuals in smaller groups fought harder. Agonistic indices were influenced by relative mean mass, focal group size, opponent group size and opponent group agonistic index. Focal group attrition rates decreased as focal group relative agonistic indices increased and there was a strong negative influence of relative mean mass. The highest focal attrition rates were received when opponent groups were numerically large and composed of large individuals. Thus, fight tactics in F. rufa seem to vary with both aspects of group RHP, group size and the individual attributes of group members, indicating that information on these are available to fighting ants.

scholarly journals Prey synchronize their vigilant behaviour with other group members

2007 ◽  
Vol 274 (1615) ◽  
pp. 1287-1291 ◽  
Author(s):  
Olivier Pays ◽  
Pierre-Cyril Renaud ◽  
Patrice Loisel ◽  
Maud Petit ◽  
Jean-François Gerard ◽  
...  
Keyword(s):  
Predation Risk ◽  
Group Size ◽  
Prey Species ◽  
Group Members ◽  
The Individual ◽  
The Cost ◽  
Group Member

It is generally assumed that an individual of a prey species can benefit from an increase in the number of its group's members by reducing its own investment in vigilance. But what behaviour should group members adopt in relation to both the risk of being preyed upon and the individual investment in vigilance? Most models assume that individuals scan independently of one another. It is generally argued that it is more profitable for each group member owing to the cost that coordination of individual scans in non-overlapping bouts of vigilance would require. We studied the relationships between both individual and collective vigilance and group size in Defassa waterbuck, Kobus ellipsiprymnus defassa , in a population living under a predation risk. Our results confirmed that the proportion of time an individual spent in vigilance decreased with group size. However, the time during which at least one individual in the group scanned the environment (collective vigilance) increased. Analyses showed that individuals neither coordinated their scanning in an asynchronous way nor scanned independently of one another. On the contrary, scanning and non-scanning bouts were synchronized between group members, producing waves of collective vigilance. We claim that these waves are triggered by allelomimetic effects i.e. they are a phenomenon produced by an individual copying its neighbour's behaviour.

Age, Sex and Prior Site Experience Have Independent Effects On the Foraging Success of Wintering Snow Buntings

Behaviour ◽  
1994 ◽  
Vol 129 (1-2) ◽  
pp. 99-111 ◽  
Author(s):  
Richard D. Smith ◽  
Neil B. Metcalfe
Keyword(s):  
Competitive Ability ◽  
Feeding Rate ◽  
Prior Experience ◽  
Residual Effects ◽  
Flock Size ◽  
Foraging Success ◽  
Feeding Rates ◽  
North East ◽  
Independent Effects ◽  
Feeding Bout

AbstractIntraspecific variation in foraging success amongst birds is often associated with differences between individuals in competitive ability or experience. However, it is usually difficult to separate the importance of experience per se from that of age. Here we examined the feeding rates of wintering snow buntings (Plectrophenax nivalis) at Cairn Gorm, North-east Scotland in both competitive and non-competitive situations. Although flock-size/density and stage of the feeding bout accounted for most of the explainable variation in peck-rates, there remained significant and additive residual effects of both age and prior experience of the site (older/more experienced birds achieving higher feeding rates) and these effects were very similar for birds feeding alone or in flocks. Sex differences in feeding rates were only apparent in large flocks, where males (the dominant sex) had faster peck-rates than females. Birds without previous experience (whether age or site-related) showed increases in relative feeding rate during the course of the winter, whereas experienced birds did not. This suggests that the differences between experienced and inexperienced birds were due to learning rather than the disproportionate loss of poor foragers.

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