Predatory behavior of a social spider, Stegodyphus sarasinorum (Araneae: Eresidae): why attack first?

1993 ◽  
Vol 71 (11) ◽  
pp. 2220-2223 ◽  
Author(s):  
Marianne B. Willey ◽  
Robert R. Jackson
Keyword(s):  
Group Size ◽  
Predatory Behavior ◽  
Feeding Time ◽  
Sri Lankan ◽  
Social Spider ◽  
Stegodyphus Sarasinorum ◽  
Communal Predation

Stegodyphus sarasinorum Karsch is a Sri Lankan social spider that exhibits communal predation and feeding. A spider's feeding time is dependent on its position in the feeding sequence, with early feeders feeding longer than those arriving later. Feeding time per spider does not decrease with increasing group size when compared with a given feeding position, temporally speaking. The first spider to feed is the only individual whose feeding time is not shortened by conspecifics.

Relationships between group size, feeding time, and agonistic behavior of mountain goats

1985 ◽  
Vol 63 (11) ◽  
pp. 2501-2506 ◽  
Author(s):  
Kenneth L. Risenhoover ◽  
James A. Bailey
Keyword(s):  
Group Size ◽  
Agonistic Behavior ◽  
Alpine Tundra ◽  
Feeding Time ◽  
Oreamnos Americanus ◽  
Movement Rates ◽  
Average Group ◽  
Risk Of Predation ◽  
Mountain Goats ◽  
Average Group Size

Relationships between group size, intragroup spacing, movement rates, foraging behavior, and frequency of agonistic behavior of mountain goats (Oreamnos americanus) using alpine tundra were examined during summer. Feeding time of goats increased with group size to about 12 goats because of a reduction in time devoted to alert behavior. Rates of movement by foraging goats increased with group size, whereas rates of agonistic behavior between goats declined with increased group size. Intragroup spacing declined as group size increased. Nannies and 2-year-old goats were more aggressive than were other sex- or age-classes. Two-year-old goats, yearlings, and billies received more threatening displays than did other classes. In Colorado, nannies with kids form large nursery bands on alpine tundra. This behavior can reduce the risk of predation to individuals while allowing nannies with kids to exploit forage away from precipitous terrain. Average group size may be a useful index to forage abundance and continuity on summer goat range.

Food Competition in Brown Capuchin Monkeys (Cebus Apella): Quantitative Effects of Group Size and Tree Productivity

Behaviour ◽  
1988 ◽  
Vol 105 (1-2) ◽  
pp. 53-76 ◽  
Author(s):  
Charles H. Janson
Keyword(s):  
Food Intake ◽  
Group Size ◽  
Food Competition ◽  
Capuchin Monkeys ◽  
Feeding Time ◽  
Net Energy ◽  
Large Trees ◽  
Capita Food ◽  
Per Capita ◽  
Large Groups

AbstractThe effects of group size and fruit availability in tree crowns on per-capita food intake was examined for wild brown capuchin monkeys living in groups of 3-12 individuals. Per-capita feeding time was nearly exactly inversely proportional to group size in small-crowned trees with little fruit, but was essentially independent of group size in large-crowned trees with abundant fruit. Despite the use of such productive trees, per-capita feeding time in the average tree visited decreased by 50% over a 4-fold range of group sizes. This cost of indirect food competition in large groups was not compensated by increased rates of ingestion, preferential use of large trees, of a higher rate of fruit tree encounter per distance travelled. Instead, foraging effort (distance travelled, number of minutes devoted to foraging, total activity minutes per day) increased at large group sizes. Estimates of total energy intake and expenditure suggest that net energy gain is constant for individuals in group sizes of 5-12. I suggest that the upper limit to group size is set by the daylength available for foraging in large groups. Aggression in food trees increased in frequency in larger groups, but the relative feeding rates of dominants and subordinates of a given rank did not appear to depend on group size. Observed decreases in per-capita food intake due to either indirect or aggressive food competition within large groups are substantially greater than the 4% gain in mean food intake that large groups achieve by displacing smaller groups from fruit trees.

scholarly journals Trait overdispersion and the role of sociality in the assembly of social spider communities across the Americas

2018 ◽  
Vol 115 (23) ◽  
pp. 6010-6015 ◽  
Author(s):  
Philippe Fernandez-Fournier ◽  
Jennifer Guevara ◽  
Catherine Hoffman ◽  
Leticia Avilés
Keyword(s):  
Body Size ◽  
Group Size ◽  
Abiotic Factors ◽  
Social Systems ◽  
Null Model ◽  
Niche Space ◽  
Social Spider ◽  
The Social ◽  
Size And Morphology

Among the factors that may lead to differences in resource use among closely related species, body size and morphology have been traditionally considered to play a role in community assembly. Here we argue that for animals that live and forage in groups, level of sociality, reflecting differences in group size and cooperative tendencies, can be an additional and powerful dimension separating species in niche space. We compare 50+ communities of the social spider genus Anelosimus across the Americas against a null model that accounts for known effects of biotic and abiotic factors on the distribution of social systems in the genus. We show that these communities are more overdispersed than expected by chance in either or both body size and level of sociality, traits we have previously shown to be associated with differences in resource utilization (prey size, microhabitat, and phenology). We further show that the contribution of sociality to differences in the size of the prey captured is two to three times greater than that of body size, suggesting that changes in group size and cooperative tendencies may be more effective than changes in body size at separating species in niche space.

scholarly journals Behaviour of domestic rabbits during 2 weeks after weaning

2019 ◽  
Vol 62 (1) ◽  
pp. 49-57
Author(s):  
Sandra Kaźmierczak ◽  
Aleksandra Cwojdzińska ◽  
Marcin T. Górecki
Keyword(s):  
Local Time ◽  
Group Size ◽  
Time Of Day ◽  
Feeding Time ◽  
Agonistic Behaviour ◽  
Domestic Rabbits

Abstract. Thirty three rabbits from five litters that were weaned at the age of 5 weeks were observed. The animals were kept in pens that were enriched with an elevation made of bricks. In total, 150 h of observations made at feeding time (07:30–10:00 and 18:00–20:30 LT, local time) were analysed. A number of affiliative, exploratory, comfort, eating, resting and locomotor behaviours were observed. Agonistic behaviour was not observed. Rabbits showed companion and location preferences: 56 % of animals had a preferred companion, and 84 % preferred a particular place in the pen. Significant effects of group size and time of day on the frequency of some forms of behaviour were found, e.g. rabbits performed comfort behaviours more often in the morning. Sex did not influence the rabbits' behaviour. Correlations were also found between different forms of behaviour, e.g. animals that performed more exploratory behaviours also showed more locomotor behaviours and affiliative interactions.

Web architecture, dynamics and silk investment in the social spider Stegodyphus sarasinorum

2021 ◽  
Vol 179 ◽  
pp. 139-146
Author(s):  
Thejasvi Beleyur ◽  
Tejas G. Murthy ◽  
Saurabh Singh ◽  
Hema Somanathan ◽  
Divya Uma
Keyword(s):  
Social Spider ◽  
Web Architecture ◽  
The Social ◽  
Stegodyphus Sarasinorum

scholarly journals Personality composition is more important than group size in determining collective foraging behaviour in the wild

2014 ◽  
Vol 281 (1796) ◽  
pp. 20141424 ◽  
Author(s):  
Carl N. Keiser ◽  
Jonathan N. Pruitt
Keyword(s):  
Group Size ◽  
Foraging Behaviour ◽  
Collective Behaviour ◽  
Nest Architecture ◽  
Social Spider ◽  
The Social ◽  
In The Wild ◽  
Behavioural Phenotypes ◽  
Collective Foraging ◽  
Animal Societies

Describing the factors that shape collective behaviour is central to our understanding of animal societies. Countless studies have demonstrated an effect of group size in the emergence of collective behaviours, but comparatively few have accounted for the composition/diversity of behavioural phenotypes, which is often conflated with group size. Here, we simultaneously examine the effect of personality composition and group size on nest architecture and collective foraging aggressiveness in the social spider Stegodyphus dumicola . We created colonies of two different sizes (10 or 30 individuals) and four compositions of boldness (all bold, all shy, mixed bold and shy, or average individuals) in the field and then measured their collective behaviour. Larger colonies produced bigger capture webs, while colonies containing a higher proportion of bold individuals responded to and attacked prey more rapidly. The number of attackers during collective foraging was determined jointly by composition and size, although composition had an effect size more than twice that of colony size: our results suggest that colonies of just 10 bold spiders would attack prey with as many attackers as colonies of 110 ‘average’ spiders. Thus, personality composition is a more potent (albeit more cryptic) determinant of collective foraging in these societies.

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