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Other Ant Species (other + ant_species)

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Life Sciences	100%

Selected Abstracts

Elevated dominance of extrafloral nectary-bearing plants is associated with increased abundances of an invasive ant and reduced native ant richness

DIVERSITY AND DISTRIBUTIONS, Issue 5 2009
Amy M. Savage
Abstract Aim, Invasive ants can have substantial and detrimental effects on co-occurring community members, especially other ants. However, the ecological factors that promote both their population growth and their negative influences remain elusive. Opportunistic associations between invasive ants and extrafloral nectary (EFN)-bearing plants are common and may fuel population expansion and subsequent impacts of invasive ants on native communities. We examined three predictions of this hypothesis, compared ant assemblages between invaded and uninvaded sites and assessed the extent of this species in Samoa. Location, The Samoan Archipelago (six islands and 35 sites). Methods, We surveyed abundances of the invasive ant Anoplolepis gracilipes, other ant species and EFN-bearing plants. Results,Anoplolepis gracilipes was significantly more widely distributed in 2006 than in 1962, suggesting that the invasion of A. gracilipes in Samoa has progressed. Furthermore, (non- A. gracilipes) ant assemblages differed significantly between invaded and uninvaded sites. Anoplolepis gracilipes workers were found more frequently at nectaries than other plant parts, suggesting that nectar resources were important to this species. There was a strong, positive relationship between the dominance of EFN-bearing plants in the community and A. gracilipes abundance on plants, a relationship that co-occurring ants did not display. High abundances of A. gracilipes at sites dominated by EFN-bearing plants were associated with low species richness of native plant-visiting ant species. Anoplolepis gracilipes did not display any significant relationships with the diversity of other non-native ants. Main conclusions, Together, these data suggest that EFN-bearing plants may promote negative impacts of A. gracilipes on co-occurring ants across broad spatial scales. This study underscores the potential importance of positive interactions in the dynamics of species invasions. Furthermore, they suggest that conservation managers may benefit from explicit considerations of potential positive interactions in predicting the identities of problematic invaders or the outcomes of species invasions. [source]

Preliminary investigations into a potential ant invader in Kruger National Park, South Africa

AFRICAN JOURNAL OF ECOLOGY, Issue 3 2010
Hendrik Sithole
Abstract The super-abundance of Lepisiota incisa (Forel) in settlement areas of Kruger National Park, South Africa has raised concerns that it might be exotic and could negatively impact on natural ecosystems. We documented the current distribution of this ant species around the main settlement in Kruger, assessed how ant diversity varies across habitats, and investigated potential mechanisms facilitating dominance by L. incisa. Around the main camp of Skukuza, pitfall traps were set in five habitats differing in anthropogenic influence. Baiting trails were conducted to determine whether L. incisa and native ants differed in numerical and behavioural dominance. Aggression assays were performed on L. incisa to provide information on colony structure. Although L. incisa was found in all habitats, it had a significantly higher abundance in gardens and appears confined to human-disturbed areas. It was numerically dominant recruiting more workers to food baits than all other ant species combined. Aggression levels were low between most nests of L. incisa indicating a potential supercolony structure. More information is urgently needed on the genetics, physiology and origins of L. incisa, and monitoring of its current distribution is recommended. This species warrants attention because there may be significant potential for overseas invasion. Résumé La surabondance de Lepisiota incisa (Forel) dans des zones d'installations du Parc National Kruger, en Afrique du Sud, a suscité des inquiétudes quant au fait que cette espèce pourrait être exotique et avoir un impact négatif sur des écosystèmes naturels. Nous avons documenté la distribution actuelle de cette espèce de fourmi autour de la principale installation dans le Kruger, évalué comment la diversité des fourmis varie selon les habitats et étudié les mécanismes éventuels qui pourraient faciliter la dominance de L. incisa. On a installé des pièges autour du camp principal de Skukuza, dans cinq habitats où l'influence anthropogénique diffère. On a réalisé des pistes appâts pour déterminer si L. incisa et les fourmis indigènes différaient en matière de dominance numérique et comportementale. Nous avons fait des essais d'agression sur L. incisa pour donner des informations sur la structure de la colonie. Bien que l'on ait trouvéL. incisa dans tous les habitats, elle était beaucoup plus abondante dans les jardins et elle semble se confiner aux endroits perturbés par les hommes. Elle était numériquement dominante, recrutant plus d'ouvrières pour les appâts que toutes les autres espèces mises ensemble. Le niveau d'agression entre la plupart des nids de L. incisaétait bas, ce qui indique peut-être une structure de super-colonie. Il faut obtenir d'urgence d'autres informations sur la génétique, la physiologie et les origines de L. incisa et l'on recommande de faire le suivi de sa distribution actuelle. Cette espèce mérite l'attention parce qu'elle peut certainement être une espèce invasive outre-mer. [source]

Response of an open-forest ant community to invasion by the introduced ant, Pheidole megacephala

AUSTRAL ECOLOGY, Issue 3 2000
C. Vanderwoude
Abstract The introduced tramp ant, Pheidole megacephala, is a well-known pest of urban areas and coastal dune ecosystems in eastern Australia. Until recently, establishment and spread of P. megacephala colonies has been regarded as likely only in disturbed areas. Here we describe the extent of an established colony of P. megacephala in a long undisturbed open forest near Maryborough in southeast Queensland and compare ant community structure with those of nearby uninfested sites. Tuna baiting revealed three distinct zones: (i) a zone totally dominated by P. megacephala (at least 10 ha) where few other ant ant species were detected; (ii) a zone where P. megacephala was absent and many other ant species were found; and (iii) a zone where opportunists (species of Ochetellus and Paratrechina) competed with P. megacephala at baits. Pitfall trapping over a 9-month period resulted in 12 species being recorded at the infested site, compared with a mean of 25 species recorded at adjoining uninfested forest. Over 94% of ants recorded in pitfalls at the infested site were P. megacephala. Most notably, P. megacephala had completely displaced dominant Dolichoderines (species of Iridomyrmex), subordinate Camponotini (species of Camponotus, Opisthopsis and Polyrhachis) and other species of Pheidole which are common at forest sites. [source]

Mechanisms driving the specificity of a myrmecophyte,ant association

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2009
JULIEN GRANGIER
In the understory of pristine Guianese forests, the myrmecophyte Hirtella physophora almost exclusively shelters colonies of the plant-ant Allomerus decemarticulatus in its leaf pouches. We experimentally tested three non-mutually exclusive hypotheses concerning phenomena that can determine the species specificity of this association throughout the foundation stage of the colonies: (1) interspecific competition results in the overwhelming presence of A. decemarticulatus queens or incipient colonies; (2) exclusion filters prevent other ant species from entering the leaf pouches; and (3) host-recognition influences the choice of founding queens, especially A. decemarticulatus. Neither interspecific competition, nor the purported exclusion filters that we examined play a major role in maintaining the specificity of this association. Unexpectedly, the plant trichomes lining the domatia appear to serve as construction material during claustral foundation rather than as a filter. Finally, A. decemarticulatus queens are able to identify their host plant from a distance through chemical and/or visual cues, which is rarely demonstrated in studies on obligatory ant,plant associations. We discuss the possibility that this specific host-recognition ability could participate in shaping a compartmentalized plant-ant community where direct competition between ant symbionts is limited. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 90,97. [source]