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Author Dreier, S.; van Zweden, J.S.; D'Ettorre, P.
Title Long-term memory of individual identity in ant queens Type Journal Article
Year 2007 Publication Biology Letters Abbreviated Journal Biol Lett
Volume 3 Issue 5 Pages 459-462
Keywords Aggression; Animals; Ants/*physiology; Conditioning, Operant; Evolution; Female; *Memory; *Recognition (Psychology); Social Dominance
Abstract Remembering individual identities is part of our own everyday social life. Surprisingly, this ability has recently been shown in two social insects. While paper wasps recognize each other individually through their facial markings, the ant, Pachycondyla villosa, uses chemical cues. In both species, individual recognition is adaptive since it facilitates the maintenance of stable dominance hierarchies among individuals, and thus reduces the cost of conflict within these small societies. Here, we investigated individual recognition in Pachycondyla ants by quantifying the level of aggression between pairs of familiar or unfamiliar queens over time. We show that unrelated founding queens of P. villosa and Pachycondyla inversa store information on the individual identity of other queens and can retrieve it from memory after 24h of separation. Thus, we have documented for the first time that long-term memory of individual identity is present and functional in ants. This novel finding represents an advance in our understanding of the mechanism determining the evolution of cooperation among unrelated individuals.
Address Institute of Biology, Department of Population Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark. sdreier@bi.ku.dk
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1744-9561 ISBN Medium
Area Expedition Conference
Notes PMID:17594958 Approved no
Call Number Equine Behaviour @ team @ Serial 4649
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Author Sigurjónsdóttir, H.; Haraldsson, H.
Title Significance of Group Composition for the Welfare of Pastured Horses Type Journal Article
Year 2019 Publication Animals Abbreviated Journal Animals
Volume 9 Issue 14 Pages
Keywords horse welfare; aggression; allogrooming; pastured horses; Icelandic horse
Abstract We explore how herd composition and management factors correlate with frequencies of social interactions in horse groups. Since the welfare of horses correlates with low aggression levels and social contact opportunities, information of this kind is important. The data are a collection of records of social interactions of 426 Icelandic horses in 20 groups of at least eight horses. The complexities and limitations of the data prohibit useful statistical modelling so the results are presented descriptively. Interesting and informative patterns emerge which can be of use both in management and in future studies. Of special interest are the low levels of agonistic behaviours in breeding groups where one stallion was present. The horses were less agonistic when in groups with young foals and where group membership was stable. Unfamiliar yearlings in peer groups were especially aggressive. Allogrooming was most frequent in groups with relatively more young horses and in unstable and small groups. Interestingly, the horses allogroomed more if they had few preferred allogrooming partners. The findings show that composition (age/sex) and stability of groups are of great importance with respect to aggression levels and opportunities for establishing bonds.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title Animals
Series Volume 9 Series Issue 1 Edition
ISSN (up) 2076-2615 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 6510
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Author Flauger, B; Möstl, E.; Krueger., K.
Title The introduction of horses into new groups: Social interactions and cortisol release Type Conference Article
Year 2012 Publication Proceedings of the 2. International Equine Science Meeting Abbreviated Journal Proc. 2. Int. Equine. Sci. Mtg
Volume in press Issue Pages
Keywords Introduction technique; Aggression; Injury risk; Endocrine response; Stress; Integration horse
Abstract Domestic horses are kept in so-called “fate societies” where they have to deal with frequent mixing. Several studies have evaluated and discussed the aggression level and injury risk during the introduction of horses into new groups, but nothing is known about the endocrine responses and thus if horses experience stress during introduction.

In this study we analysed the efficiency of four approved introduction techniques and evaluated the introduction of 30 horses into 11 different groups. Horses were introduced: 1) immediately, 2) after observing the new group for several days, 3) together with an “integration horse” after several days of observation, or 4) with a mixed strategy. Aggressive as well as positive social behaviour between the introduced horses and the group members were analysed the two hours following the introduction event. In addition, we focussed on the glucocorticoid production of the newcomer horses by measuring faecal cortisol metabolites (FCM) on the day of the introduction as well as the following three days.

For the four introduction techniques we found significant differences in the horses’ aggressive and submissive behaviour as well as in their total interactions. The introduction together with an integration horse led to significantly lower levels of aggression and less total interactions than the immediate introduction of single horses.

Horses which were introduced immediately or after an observation period showed significantly elevated levels of FCM on the first, second and third day after the introduction. For horses introduced together with an integration horse FCM were already significantly higher on the day of the introduction, indicating a stressful event before the introduction itself. In contrast, FCM levels were always very low when using the mixed technique.

In sum, horses have the ability to deal with conflict when they are introduced to new group members. The introduction event itself appears not to be as stressful as previously assumed. Standing together with an “integration horse” on a separate paddock and not being able to integrate immediately into a new group appears to be stressful for the newcomer. Based on the findings of our study we suggest to introduce new horses in group management together with a new group mate, a so-called “integration horse”. This would reduce the number of total social interactions as well as the aggression level. While this technique may be stressful for the newcomer, it lowers aggressive behaviour between the introduced horse and the group members and consequently reduces injury risks.
Address
Corporate Author Flauger, B. Thesis
Publisher Xenophon Publishing Place of Publication Wald Editor Krueger, K.
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 978-3-9808134-26 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5551
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