52 research outputs found
Cultural differences in ant-dipping tool length between neighbouring chimpanzee communities at Kalinzu, Uganda.
Cultural variation has been identified in a growing number of animal species ranging from primates to cetaceans. The principal method used to establish the presence of culture in wild populations is the method of exclusion. This method is problematic, since it cannot rule out the influence of genetics and ecology in geographically distant populations. A new approach to the study of culture compares neighbouring groups belonging to the same population. We applied this new approach by comparing ant-dipping tool length between two neighbouring communities of chimpanzees (Pan troglodytes schweinfurthii) in the Kalinzu Forest, Uganda. Ant-dipping tool length varies across chimpanzee study sites in relation to army ant species (Dorylus spp.) and dipping location (nest vs. trail). We compared the availability of army ant species and dipping tool length between the two communities. M-group tools were significantly longer than S-group tools, despite identical army ant target species availabilities. Moreover, tool length in S-group was shorter than at all other sites where chimpanzees prey on epigaeic ants at nests. Considering the lack of ecological differences between the two communities, the tool length difference appears to be cultural. Our findings highlight how cultural knowledge can generate small-scale cultural diversification in neighbouring chimpanzee communities
Hybridization in East African swarm-raiding army ants
<p>Abstract</p> <p>Background</p> <p>Hybridization can have complex effects on evolutionary dynamics in ants because of the combination of haplodiploid sex-determination and eusociality. While hybrid non-reproductive workers have been found in a range of species, examples of gene-flow via hybrid queens and males are rare. We studied hybridization in East African army ants (<it>Dorylus </it>subgenus <it>Anomma</it>) using morphology, mitochondrial DNA sequences, and nuclear microsatellites.</p> <p>Results</p> <p>While the mitochondrial phylogeny had a strong geographic signal, different species were not recovered as monophyletic. At our main study site at Kakamega Forest, a mitochondrial haplotype was shared between a "<it>Dorylus molestus</it>-like" and a "<it>Dorylus wilverthi</it>-like" form. This pattern is best explained by introgression following hybridization between <it>D. molestus </it>and <it>D. wilverthi</it>. Microsatellite data from workers showed that the two morphological forms correspond to two distinct genetic clusters, with a significant proportion of individuals being classified as hybrids.</p> <p>Conclusions</p> <p>We conclude that hybridization and gene-flow between the two army ant species <it>D. molestus </it>and <it>D. wilverthi </it>has occurred, and that mating between the two forms continues to regularly produce hybrid workers. Hybridization is particularly surprising in army ants because workers have control over which males are allowed to mate with a young virgin queen inside the colony.</p
Evolutions- und Verhaltensökologie von Dorylus Treiberameisen
1\. Title 1
2\. Acknowledgements 3
3\. Table of contents 4
4\. Introduction 5
5\. Chapter 1 8
6\. Chapter 2 25
7\. Chapter 3 43
8\. General conclusions 58
9\. Summary 61
10\. Zusammenfassung 62
11\. References 64
12\. Curriculum vitae 75Dorylus army ants are considered to be keystone predator species in many
afrotropical ecosystems. Yet our knowledge of the evolutionary and behavioural
ecology of this fascinating group is still very sparse. Members of the
subgenera Alaopone, Dichtadia, Dorylus s.str., Rhogmus and Typhlopone hunt and
nest in the soil (hypogaeic life-style), while some Anomma species hunt in the
leaf-litter (members of the gerstÀckeri group, intermediate life-style) and
the others conduct massive swarm raids on the surface and up into the
vegetation (the fierce and famous driver ants, epigaeic life-style). According
to an evolutionary scenario the hypogaeic life-style is the ancestral state in
this group. To identify possible selection pressures driving the evolution of
worker morphology in this genus, I have analysed the allometries of
functionally important body traits in relation to life-style. There is a
clear-cut trend of increasing relative size of eight out of nine studied
characters from hypogaeic to intermediate to epigaeic species. The results
strongly suggest that the ecological niche shifts necessitated adaptations in
these traits. The degree of overall differentiation among species is more
pronounced in larger than in smaller workers. The pattern of division of
labour in the epigaeic D. molestus indicates that two factors that may have
caused this phenomenon are new food habits and an increased need for colony
defence of intermediate and epigaeic species respectively. In an attempt to
clarify the functional value of long front and long hind legs which are among
the traits that are very likely to represent adaptations to epigaeic foraging
I analysed the food spectrum and food transport by the two epigaeic species D.
molestus and D. wilverthi. I show that even within the category of epigaeic
species front and hind legs correlate with foraging stratum use. While D.
molestus searches in the vegetation, on the surface and intensely in the leaf-
litter and top soil layers, the longer-legged D. wilverthi appears to restrict
its hunting efforts to the vegetation and surface. D. wilverthi workers do not
carry relatively larger food items and so it is concluded that other factors
such as energy efficiency in locomotion or climbing ability may have selected
for longer legs in this species. The migration behaviour of the army ant
Dorylus molestus was studied in the montane forest of Mt Kenya. I found that
stay duration in a nest is highly variable so that brood cycle as an
underlying endogenous pattern generator can be ruled out. Local food depletion
is likely to be the ultimate cause for migrations in this species, because
migration distance is larger than foraging range and colonies move away from
their nearest neighbours. A small percentage of migrations is triggered by
pangolin attacks of nests. Despite fierce intraspecific competition colonies
do not fight other colonies contrary to the prediction of a recently developed
mathematical model for epigaeic swarm raiding Dorylus species.Treiberameisen der Gattung Dorylus werden als SchlĂŒsselarten fĂŒr verschiedene
afrotropische Ăkosysteme angesehen. Trotzdem ist unser Wissen ĂŒber die
Evolutions- und Verhaltensökologie dieser faszinierenden Gruppe sehr begrenzt.
Arten der Untergattungen Alaopone, Dichtadia, Dorylus s.str., Rhogmus und
Typhlopone jagen und nisten in der Erde (hypogÀischer Lebensstil), wohingegen
manche Anomma Arten in der Laubstreuschicht jagen (Arten der gerstĂ€ckeri ïżœ
Gruppe, intermediÀrer Lebensstil) und andere massive Schwarm-jagden auf der
BodenoberflÀche sowie bis hoch in die Vegetation unternehmen (die bekannten
und gefĂŒrchteten Treiberameisen, epigĂ€ischer Lebensstil). GemÀà eines
evolutionÀren Szenarios ist der hypogÀischer Lebensstil in dieser Gruppe der
ursprĂŒngliche Zustand. Um mögliche SelektionsdrĂŒcke zu identifizieren, die
eine Rolle in der Evolution der Arbeiterinnenmorphologie spielen, habe ich die
Allometrien verschiedener funktionell relevanter Körpermerkmale im
Zusammenhang mit den jeweiligen Lebensstilen analysiert. Dabei finde ich einen
klaren Trend von zunehmender relativer GröĂe von hypogĂ€ischem zu intermediĂ€rem
zu epigÀischem Lebensstil bei acht von neun untersuchten Merkmalen. Die
Ergebnisse deuten sehr stark darauf hin, dass die Wechsel der ökologischen
Nische Anpassungen in den entsprechenden Merkmalen notwendig machten. Die
Differenzierung zwischen den Arten ist bei den gröĂeren Arbeiterinnen stĂ€rker
ausgeprÀgt als bei kleineren. Das Muster der Arbeitsteilung in der epigÀischen
Art Dorylus molestus deutet darauf hin, dass dieses PhÀnomen durch
Erfordernisse des neuen Futterspektrums und der Kolonieverteidigung von
intermediÀren und epigÀischen Arten hervorgerufen wurde. Sowohl lange Vorder-
als auch lange Hinterbeine gehören zu den Merkmalen, die als Anpassungen an
epigÀische Lebensweise anzusehen sind. Um ihren funktionellen Wert
aufzuzeigen, habe ich das Futterspektrum und den Futtertransport der beiden
epigÀischen Arten D. molestus and D. wilverthi untersucht. Dabei konnte ich
zeigen, dass auch innerhalb der epigÀischen Kategorie Vorderbein- und
HinterbeinlÀngen mit Jagdstratumnutzung korrelieren. WÀhrend D. molestus in
der Vegetation, auf dem Boden sowie intensiv in der Laubstreuschicht und
oberen Bodenschicht nach Beute sucht, beschrÀnkt die langbeinigere D.
wilverthi ihre JagdaktivitÀten auf die Vegetation und BodenoberflÀche. Trotz
ihrer lÀngeren Beine tragen D. wilverthi Arbeiterinnen aber nicht relativ
gröĂere Beutetierfragmente, so dass sich folgern lĂ€sst, dass andere Faktoren
wie Energieeffizienz in der Lokomotion oder KletterfÀhigkeit die lÀngeren
Beine selektiv gefördert haben mĂŒssen. Das Wanderverhalten der Art Dorylus
molestus wurde in dem Bergwald am Mt Kenya untersucht. Ich fand heraus, dass
die Aufenthaltsdauer in einem Nest sehr variabel war, so dass ein Brutzyklus
als endogener Rhythmusgenerator fĂŒr die Migrationen ausgeschlossen werden
kann. Lokale Erschöpfung der Futterressourcen ist sehr wahrscheinlich die
entscheidende Ursache fĂŒr Wanderungen, weil Wanderdistanzen gröĂer als
Futterjagddistanzen sind, und Kolonien von ihren nÀchsten Nachbarn
fortwandern. Ein kleiner Prozentsatz der Wanderungen wird durch Angriffe von
Schuppentieren auf Nester verursacht. Trotz starker intraspezifischer
Konkurrenz kÀmpfen Kolonien nicht gegeneinander im Gegensatz zu den
Vorhersagen eines kĂŒrzlich fĂŒr epigĂ€ische schwarmjagende Dorylus-Arten
entwickelten mathematischen Modells
Does the afrotropical army ant <em>Dorylus</em> (<em>Anomma</em>) <em>molestus</em> go extinct in fragmented forests?
Temporal and spatial patterns in the emigrations of the army ant <em>Dorylus</em> (<em>Anomma</em>) <em>molestus</em> in the montane forest of Mt Kenya
SNP dataset for 148 Kenyan, African and Eurasian honey bees (part 5)
This dataset contains the 13+ million SNPs that were detected between 148 Kenyan, African and Eurasian honey bees using FreeBayes and that passed quality filtering. Details for SNP processing, sample labels and quality control is provided in the paper and its supplementary information.
The original 148_honeybees.vcf.gz input file has been split into fourteen numbered parts (0 to 13). After downloading all parts, they can be joined to recreate the original file using the follwing UNIX command: cat 148_honeybees.vcf.gz.{0..13}.split > 148_honeybees.vcf.gz
The VCF file can then be unzipped using the UNIX command: gunzip 148_honeybees.vcf.g
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