2,014 research outputs found
Königgrätz / Entw u. gez. v. F. Handke, Terrain unter dessen Leitung v. Ant. Pohl ; Situation u. Schrift gest. v. H. Herzberg, Berge v. H. Petters i. Hildbghsn.
No full textKÖNIGGRÄTZ / ENTW U. GEZ. V. F. HANDKE, TERRAIN UNTER DESSEN LEITUNG V. ANT. POHL ; SITUATION U. SCHRIFT GEST. V. H. HERZBERG, BERGE V. H. PETTERS I. HILDBGHSN.
G. D. Reymann's topographische Special-Karte von Central-Europa (-)
Königgrätz / Entw u. gez. v. F. Handke, Terrain unter dessen Leitung v. Ant. Pohl ; Situation u. Schrift gest. v. H. Herzberg, Berge v. H. Petters i. Hildbghsn. (188) ( -
Predation success by a plant-ant indirectly favours the growth and fitness of its host myrmecophyte
No full textMutualisms, or interactions between species that lead to net fitness benefits for each species involved, are stable and
ubiquitous in nature mostly due to "byproduct benefits" stemming from the intrinsic traits of one partner that generate an indirect and positive outcome for the other. Here we verify if myrmecotrophy (where plants obtain nutrients from the refuse of their associated ants) can explain the stability of the tripartite association between the myrmecophyte Hirtella physophora, the ant Allomerus decemarticulatus and an Ascomycota fungus. The plant shelters and provides the ants with extrafloral nectar. The ants protect the plant from herbivores and integrate the fungus into the construction of a trap that they use to capture prey; they also provide the fungus and their host plant with nutrients. During a 9-month field study, we
over-provisioned experimental ant colonies with insects, enhancing colony fitness (i.e., more winged females were
produced). The rate of partial castration of the host plant, previously demonstrated, was not influenced by the experiment. Experimental plants showed higher δ¹⁵N values (confirming myrmecotrophy), plus enhanced vegetative growth (e.g., more leaves produced increased the possibility of lodging ants in leaf pouches) and fitness (i.e., more fruits produced and more flowers that matured into fruit). This study highlights the importance of myrmecotrophy on host plant fitness and the stability of ant-myrmecophyte mutualisms
Social integration of macroparasites in ant societies: ultimate and proximate mechanisms
No full textAnt colonies are commonly parasitized simultaneously by several species. While some parasites are recognized and attacked by their ant hosts, others have apparently cracked the ants’ recognition code and interact mainly peacefully with their hosts. Although such apparent differences in social integration among ant parasites have been described, the underlying mechanisms resulting in differential integration remain mostly unknown. Using Leptogenys army ants and their parasites, I studied ultimate mechanisms that might be responsible for differing integration levels by comparing the strength of host defence with the negative impact of parasites. In addition, I investigated proximate mechanisms of differing integration levels by evaluating the role of chemical deception by mimicry.
The interactions of several parasitic beetle species with their Leptogenys hosts revealed that particular species fed on host larvae, while others did not. The hosts’ aggressiveness was enhanced towards brood-killing species, while non-predatory species received almost no aggression, resulting in social integration. Accordingly, the fitness costs of parasites likely influence the evolution of host defences against them in a multi-parasite situation.
The role of chemical mimicry has been investigated in detail for two kleptoparasites, namely the silverfish Malayatelura ponerophila and the spider Gamasomorpha maschwitzi. By analyzing the transfer of a chemical label from the host ants to the parasites, I empirically demonstrated for the first time that ant parasites are able to acquire mimetic compounds from their host. Additional biosynthesis of mimetic compounds seems unlikely in both parasites, since the concentration of each cuticular hydrocarbon decreased in individuals that were isolated from the host. In addition, a high accuracy in chemical host resemblance was shown to be beneficial for the social integration of both parasites. Reduced accuracy in chemical host resemblance resulted either in aggressive host responses towards the silverfish or elevated host inspection behaviour towards the spider. The degree of dependency on chemical mimicry to achieve social integration differed considerably between the two parasites, however.
Accordingly, the parasites’ level of social integration is affected by ultimate mechanisms such as the negative impact on the host as well as by proximate mechanisms such as the degree of accuracy in chemical host resemblance
Trace metal concentrations during POLARSTERN cruise ANT-XXIII/1
No full textTrace metal concentrations during POLARSTERN cruise ANT-XXIII/
The microstructure morphology on ant footpads and its effect on ant adhesion
No full textAnts show a bionic application prospect due to their special climbing ability. However, different ant species living in different environments exhibit different adhesion abilities. In order to reveal their mechanical mechanisms, footpads of four representative ant species are investigated experimentally. Regular microstructures on the ventral side of ant footpads are clearly observed, which possess different shapes and sizes for different ant species. The normal adhesion force for each kind of ant is further measured with a spinning technique, which is significantly affected by the microstructure on the ventral surface of ant footpads. Theoretical models are established in order to disclose the mechanical mechanism, in which both the capillary force and the van der Waals interaction are considered. It is found that the real contact area depends significantly on the microstructures on the ventral side, which further affects the total adhesion force. The coexistence mechanism of wet and dry adhesion for ant footpads is proposed. The finding in the present paper should be useful for deep understanding of the adhesion mechanism of different ant species and helpful for the design of bio-inspired intelligent adhesion surfaces
Decision making during the scouting behaviour of the slave-making ant Protomognathus americanus
No full textCarpenter ant control
No full textTitle from PDF cover (viewed on December 14, 2017).This archived document is maintained by the State Library of Oregon as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposes.Mode of access: Internet from the Oregon Government Publications Collection.Text in English
The evolution of ant (Hymenoptera: Formicidae): head morphology
No full textAnts are the most speciose group of eusocial insects. Species of the family Formicidae are dominant in most terrestrial ecosystems and different ant species have widely different life habits. As diverse as ant lifestyles are also their body forms. This diversity is well documented in the systematic, taxonomic literature. However, while early ant systematists such as Carlo Emery and Auguste Forel incorporated anatomical features such as the proventriculus in their inferences, most of the taxonomic and phylogenetic work since then has focused almost exclusively on external characters. In recent years, the use of morphology for phylogenetic reconstruction has declined dramatically with the rise of molecular phylogenetics. While this has led to immense progress in inferring the relationships of the different ant clades, phenotypic evolutionary reconstruction has not progressed to the same degree. This is exemplified by the lack of a single morphological autapomorphy of the “formicoid clade” (Doryloformicia), a grouping containing most of extant ant diversity and consistently recovered in molecular analyses. To begin closing the gaps, I set out the following goals for this dissertation: 1) solidly documenting ant head anatomy across a wide taxon sample, 2) making the terminology compatible with that of other insect groups and develop morphological concepts where necessary, 3) reconstructing character evolution of the ant head, 4) contributing to our functional understanding of the head, and 5) optimizing the workflow for the anatomical study of ants and other insects. To reach this, I have mostly studied ant morphology using µCT-scan based 3d-reconstructions, but also other traditional morphological techniques. My goals were reached to varying degrees in the seven publications forming this thesis. Through my detailed anatomical studies of the ant head I have layed a new groundwork to understand ant phenotypic evolution
Odorant Binding Proteins of the Red Imported Fire Ant, Solenopsis invicta: An Example of the Problems Facing the Analysis of Widely Divergent Proteins
No full textPMCID: PMC3031547This is an open-access article distributed under the terms of the Creative Commons Public Domain declaration which stipulates that, once placed in the public domain, this work may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose
Convergence of ant colony multi-agent swarms
No full textAnt Colony algorithms are a set of biologically inspired algorithms used commonly to solve distributed optimization problems. Convergence has been proven in the context of optimization processes, but these proofs are not applicable in the framework of robotic control. In order to use Ant Colony algorithms to control robotic swarms, we present in this work more general results that prove asymptotic convergence of a multi-agent Ant Colony swarm moving in a weighted graph.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Team Tamas Keviczk
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