The Experts below are selected from a list of 2298 Experts worldwide ranked by ideXlab platform
Laurent Keller - One of the best experts on this subject based on the ideXlab platform.
-
genetic compatibility affects division of labor in the argentine ant Linepithema Humile
Evolution, 2013Co-Authors: Romain Libbrecht, Laurent KellerAbstract:Division of labor is central to the organization of insect societies. Within-colony comparisons between subfamilies of workers (patrilines or matrilines) revealed genetic effects on division of labor in many social insect species. Although this has been taken as evidence for additive genetic effects on division of labor, it has never been experimentally tested. To determine the relative roles of additive and nonadditive genetic effects (e.g., genetic compatibility, epistasis, and parent-of-origin imprinting effects) on worker behavior, we performed controlled crosses using the Argentine ant Linepithema Humile. Three of the measured behaviors (the efficiency to collect pupae, the foraging propensity, and the distance between non-brood-tenders and brood) were affected by the maternal genetic background and the two others (the efficiency to feed larvae and the distance between brood-tenders and brood) by the paternal genetic background. Moreover, there were significant interactions between the maternal and paternal genetic backgrounds for three of the five behaviors. These results are most consistent with parent-of-origin and genetic compatibility effects on division of labor. The finding of nonadditive genetic effects is in strong contrast with the current view and has important consequences for our understanding of division of labor in insect societies.
-
Multilevel genetic analyses of two European supercolonies of the Argentine ant, Linepithema Humile.
Molecular ecology, 2005Co-Authors: Julie Jaquiéry, Valérie Vogel, Laurent KellerAbstract:Some ants have an extraordinary unicolonial social organization, whereby individuals mix freely among physically separated nests. Recently, it was shown that the European population of Linepithema Humile consisted of two enormous unicolonial supercolonies. Workers of the same supercolony are never aggressive to each other. In contrast, aggressiveness is invariably high between workers from different supercolonies. Here we investigated whether gene flow occurs between two supercolonies. We identified a contact zone in which we sampled 46 nests. For each nest, aggression tests were conducted against workers from reference nests from both supercolonies. Workers were always very aggressive towards workers of one of the supercolonies but not to workers of the other. Thus, all nests could be clearly assigned to one of the two supercolonies. For 22 of the 46 nests, we genotyped 15–16 workers at five microsatellite loci. A four-level hierarchical analysis of variance revealed very strong genetic differentiation between the two supercolonies ( F SUPERCOLONY-TOTAL = 0.541) and low differentiation between sectors (i.e. group of nests connected together with trails) within supercolonies ( F SECTOR-SUPERCOLONY = 0.064). The very high differentiation between the two supercolonies indicates a lack of ongoing gene flow, a conclusion further bolstered by the finding that the two supercolonies share no common alleles at two of the five microsatellite loci. A Bayesian clustering method also revealed the occurrence of two distinct clusters. These clusters exactly match the grouping obtained by aggression tests. None of the 332 genotyped individuals were admixed despite the fact that some nests of the two supercolonies were separated by less than 30 m. These results demonstrate that the two supercolonies have completely separate gene pools.
-
Loss of Wolbachia infection during colonisation in the invasive Argentine ant Linepithema Humile.
Heredity, 2004Co-Authors: Max Reuter, Jes S. Pedersen, Laurent KellerAbstract:Wolbachia are maternally inherited bacteria, which are very common in arthropods and nematodes. Wolbachia infection may affect host reproduction through feminisation, parthenogenesis, male-killing, cytoplasmic incompatibility and increased fecundity. Previous studies showing discrepancies between the phylogenies of Wolbachia and its arthropod hosts indicate that infection is frequently lost, but the causes of symbiont extinction have so far remained elusive. Here, we report data showing that colonisation of new habitats is a possible mechanism leading to the loss of infection. The presence and prevalence of Wolbachia were studied in three native and eight introduced populations of the Argentine ant Linepithema Humile. The screening shows that the symbiont is common in the three native L. Humile populations analysed. In contrast, Wolbachia was detected in only one of the introduced populations. The loss of infection associated with colonisation of new habitats may result from drift (founder effect) or altered selection pressures in the new habitat. Furthermore, a molecular phylogeny based on sequences of the Wolbachia wsp gene indicates that L. Humile has been infected by a single strain. Horizontal transmission of the symbiont may be important in ants as suggested by the sequence similarity of strains in the three genera Linepithema, Acromyrmex, and Solenopsis native from South and Central America.
-
Lack of inbreeding avoidance in the Argentine ant Linepithema Humile
Behavioral Ecology, 2002Co-Authors: Laurent Keller, Denis FournierAbstract:Although workers might increase their inclusive fitness by favoring closer over more distant kin, evidence suggest that nepotism generally does not occur within colonies of social insects. It has been suggested that this may be due to the cost of recognition errors. We tested whether recognition occurs in a system where a better than random ability to recognize kin should be selected for. Using DNA microsatellites, we show that sexuals of the Argentine ant Linepithema Humile fail to use genetic cues to avoid sib-mating. When offspring of two queens were allowed to mate, the percentage of matings among siblings was not significantly lower than expected under the hypothesis of random mating. The finding that sexuals fail to use genetic cues to avoid sibmatings cannot be attributed to the cost of recognition errors because any recognition system that would lead to a better than random ability to avoid sib-mating should be selected for when there are costs to inbreeding. These data are thus consistent with the view that kin recognition mediated solely by genetic cues might be intrinsically error prone within colonies of social insects. Key words: Argentine ants, inbreeding, kin recognition, Linepithema Humile, recognition errors, sib-mating. [Behav Ecol 13:28–31 (2002)]
-
Kin structure and queen execution in the Argentine ant Linepithema Humile
Journal of Evolutionary Biology, 2001Co-Authors: Max Reuter, Francois Balloux, Laurent Lehmann, Laurent KellerAbstract:Every spring, workers of the Argentine Ant Linepithema Humile kill a large proportion of queens within their nests. Although this behaviour inflicts a high energetic cost on the colonies, its biological significance has remained elusive so far. An earlier study showed that the probability of a queen being executed is not related to her weight, fecundity, or age. Here we test the hypothesis that workers collectively eliminate queens to which they are less related, thereby increasing their inclusive fitness. We found no evidence for this hypothesis. Workers of a nest were on average not significantly less related to executed queens than to surviving ones. Moreover, a population genetic analysis revealed that workers were not genetically differentiated between nests. This means that workers of a given nest are equally related to any queen in the population and that there can be no increase in average worker–queen relatedness by selective elimination of queens. Finally, our genetic analyses also showed that, in contrast to workers, queens were significantly genetically differentiated between nests and that there was significant isolation by distance for queens.
Theresa C. Wossler - One of the best experts on this subject based on the ideXlab platform.
-
Controlling invasive Argentine ants, Linepithema Humile, in conservation areas using horizontal insecticide transfer.
Scientific reports, 2019Co-Authors: Grzegorz Buczkowski, Theresa C. WosslerAbstract:Invasive ants are major agricultural and urban pests and a significant concern in conservation areas. Despite long history of control and eradication efforts, invasive ants continue to spread around the globe driven by a multitude of synergistic factors. Lack of effective management tools is one of the biggest challenges in controlling invasive ants. The goal of the current study was to improve the efficacy and safety of ant management and to develop effective control strategies for sensitive conservation areas. We utilized the Argentine ant (Linepithema Humile) as a model system to evaluate a target-specific pesticide delivery system that exploits the interconnected nature of social insect colonies to distribute a toxicant effectively within the colony. The approach, based entirely on horizontal transfer, takes advantage of various levels of social interactions in ant colonies to disseminate a toxicant throughout the colony. Results of laboratory studies coupled with LC/MS/MS analysis demonstrate that fipronil is toxic to Argentine ants in extremely small (nanogram) quantities and is efficiently transferred from a single treated donor to multiple recipients, causing significant secondary mortality. A field study was conducted in native fynbos plots invaded by Argentine ants. The study consisted of collecting naive workers, treating them with fipronil, and releasing them within invaded plots. Results show that the release of fipronil-treated ants reduced Argentine ant abundance by >90% within 24 h. The horizontal transfer approach offers environmental benefits with regard to pesticide use in ecologically sensitive environments and appears ideally suited for ant management in conservation areas.
-
let them eat termites prey baiting provides effective control of argentine ants Linepithema Humile in a biodiversity hotspot
Journal of Applied Entomology, 2018Co-Authors: Grzegorz Buczkowski, Natasha P. Mothapo, Theresa C. WosslerAbstract:Invasive ants threaten biodiversity, ecosystem services and agricultural systems. This study evaluated a prey-baiting approach for managing Argentine ants in natural habitat invaded by Argentine ants. Blackmound termites (Amitermes hastatus) were topically exposed to fipronil and presented to Argentine ants (Linepithema Humile). In laboratory assays, L. Humile colonies were offered fipronil-treated termites within experimental arenas. The termites were readily consumed, and results demonstrate that a single termite topically treated with 590 ng fipronil is capable of killing at least 500 L. Humile workers in 4 days. Field studies were conducted in natural areas invaded by L. Humile. Fipronil-treated termites scattered within experimental plots provided rapid control of L. Humile and ant densities throughout the treated plots declined by 98 ± 5% within 21 days. Results demonstrate that the prey-baiting approach is highly effective against L. Humile and may offer an effective alternative to traditional bait treatments. Furthermore, prey-baiting offers environmental benefits by delivering substantially less toxicant to the environment relative to current control methods which rely on commercial bait formulations and may offer greater target specificity.
-
Let them eat termites—prey-baiting provides effective control of Argentine ants, Linepithema Humile, in a biodiversity hotspot
Journal of Applied Entomology, 2018Co-Authors: Grzegorz Buczkowski, Natasha P. Mothapo, Theresa C. WosslerAbstract:Invasive ants threaten biodiversity, ecosystem services and agricultural systems. This study evaluated a prey-baiting approach for managing Argentine ants in natural habitat invaded by Argentine ants. Blackmound termites (Amitermes hastatus) were topically exposed to fipronil and presented to Argentine ants (Linepithema Humile). In laboratory assays, L. Humile colonies were offered fipronil-treated termites within experimental arenas. The termites were readily consumed, and results demonstrate that a single termite topically treated with 590 ng fipronil is capable of killing at least 500 L. Humile workers in 4 days. Field studies were conducted in natural areas invaded by L. Humile. Fipronil-treated termites scattered within experimental plots provided rapid control of L. Humile and ant densities throughout the treated plots declined by 98 ± 5% within 21 days. Results demonstrate that the prey-baiting approach is highly effective against L. Humile and may offer an effective alternative to traditional bait treatments. Furthermore, prey-baiting offers environmental benefits by delivering substantially less toxicant to the environment relative to current control methods which rely on commercial bait formulations and may offer greater target specificity.
-
The attractiveness of toxic bait is not always accompanied by increased mortality in laboratory colonies of Argentine ants, Linepithema Humile(Hymenoptera: Formicidae)
African Entomology, 2016Co-Authors: Natasha P. Mothapo, Theresa C. WosslerAbstract:The Argentine ant, Linepithema Humile, is a globally known invasive ant species responsible for widespread biodiversity and economic loss, thus there is a growing need to control and preferably locally eradicate these ants from invaded environments and households. We evaluated the attractiveness and toxicity of six commercial baits containing hydramethylnon, imidacloprid and pyriproxyfen targeting Argentine ants, and differing in bait formulation. Hydramethylnon granular baits were most effective, killing workers (85–100% worker mortality) and queens (63–75 %) in the laboratory within 24 h. Workers were most attracted to and consumed the most of the imidacloprid gel bait, but, contrary to previous studies, mortality on this bait was low. The pyriproxyfen bait was least effective in killing workers, as was expected, and was the least consumed of all baits.We advocate the use of a fine granular hydramethylnon formulation for the effective control of Argentine ants. The attractiveness and consumption of the ...
-
Behavioural and chemical evidence for multiple colonisation of the Argentine ant, Linepithema Humile , in the Western Cape, South Africa
BMC ecology, 2011Co-Authors: Natasha P. Mothapo, Theresa C. WosslerAbstract:Background: The Argentine ant, Linepithema Humile, is a widespread invasive ant species that has successfully established in nearly all continents across the globe. Argentine ants are characterised by a social structure known as unicoloniality, where territorial boundaries between nests are absent and intraspecific aggression is rare. This is particularly pronounced in introduced populations and results in the formation of large and spatially expansive supercolonies. Although it is amongst the most well studied of invasive ants, very little work has been done on this ant in South Africa. In this first study, we investigate the population structure of Argentine ants in South Africa. We use behavioural (aggression tests) and chemical (CHC) approaches to investigate the population structure of Argentine ants within the Western Cape, identify the number of supercolonies and infer number of introductions. Results: Both the aggression assays and chemical data revealed that the Western Cape Argentine ant population can be divided into two behaviourally and chemically distinct supercolonies. Intraspecific aggression was evident between the two supercolonies of Argentine ants with ants able to discriminate among conspecific non-nestmates. This discrimination is linked to the divergence in cuticular hydrocarbon profiles of ants originating from the two supercolonies. Conclusions: The presence of these two distinct supercolonies is suggestive of at least two independent
Jules Silverman - One of the best experts on this subject based on the ideXlab platform.
-
Propagule pressure and climate contribute to the displacement of Linepithema Humile by Pachycondyla chinensis.
PloS one, 2013Co-Authors: Eleanor Spicer Rice, Jules SilvermanAbstract:Identifying mechanisms governing the establishment and spread of invasive species is a fundamental challenge in invasion biology. Because species invasions are frequently observed only after the species presents an environmental threat, research identifying the contributing agents to dispersal and subsequent spread are confined to retrograde observations. Here, we use a combination of seasonal surveys and experimental approaches to test the relative importance of behavioral and abiotic factors in determining the local co-occurrence of two invasive ant species, the established Argentine ant (Linepithema Humile Mayr) and the newly invasive Asian needle ant (Pachycondyla chinensis Emery). We show that the broader climatic envelope of P. chinensis enables it to establish earlier in the year than L. Humile. We also demonstrate that increased P. chinensis propagule pressure during periods of L. Humile scarcity contributes to successful P. chinensis early season establishment. Furthermore, we show that, although L. Humile is the numerically superior and behaviorally dominant species at baits, P. chinensis is currently displacing L. Humile across the invaded landscape. By identifying the features promoting the displacement of one invasive ant by another we can better understand both early determinants in the invasion process and factors limiting colony expansion and survival.
-
Impact of Linepithema Humile and Tapinoma sessile (Hymenoptera: Formicidae) on three natural enemies of Aphis gossypii (Hemiptera: Aphididae)
Biological Control, 2010Co-Authors: Bradford E. Powell, Jules SilvermanAbstract:Abstract Ants frequently protect honeydew-excreting hemipterans from their natural enemies in exchange for food, and these interactions can have a negative impact on biological control. Invasive ant species, such as the Argentine ant, Linepithema Humile (Mayr), enter into mutualisms with some hemipteran species and are generally regarded as more aggressive than native ants. Consequently, they may be more effective at protecting honeydew-producing hemipterans from natural enemy attack. We compared changes in populations of Aphis gossypii (Glover) tended by equal numbers of invasive L. Humile, and the North America native Tapinoma sessile (Say), when exposed to the natural enemies Chrysoperla carnea (Stephens), Hippodamia convergens (Guer.) and Aphidius colemani (Viereck). While more L. Humile than T. sessile workers foraged on plants with A. gossypii, both ants were equally effective at protecting A. gossypii from their natural enemies when aphid populations were relatively low. Using larger starting populations, A. gossypii were less negatively impacted by C. carnea or H. convergens when tended by L. Humile than T. sessile. In a field experiment, the number of Aphis gossypii on plants with L. Humile or T. sessile were greater than on plants without ants. We conclude that due to its higher foraging tempo L. Humile may more effectively patrol plant surfaces supporting honeydew-producing hemipterans than T. sessile, which may, in part, underlie the success of this invasive ant.
-
Diet-related modification of cuticular hydrocarbon profiles of the Argentine ant, Linepithema Humile, diminishes intercolony aggression.
Journal of chemical ecology, 2005Co-Authors: Grzegorz Buczkowski, Ranjit Kumar, Steven L. Suib, Jules SilvermanAbstract:Territorial boundaries between conspecific social insect colonies are maintained through a highly developed nestmate recognition system modulated by heritable and, in some instances, nonheritable cues. Argentine ants, Linepithema Humile, use both genetic and environmentally derived cues to discriminate nestmates from nonnestmates. We explored the possibility that intraspecific aggression in the Argentine ant might diminish when colonies shared a common diet. After segregating recently field-collected colony pairs into high or moderate aggression categories, we examined the effect of one of three diets: two hydrocarbon-rich insect prey, Blattella germanica and Supella longipalpa, and an artificial (insect-free) diet, on the magnitude of aggression loss. Aggression diminished between colony pairs that were initially moderately aggressive. However, initially highly aggressive colony pairs maintained high levels of injurious aggression throughout the study, independent of diet type. Each diet altered the cuticular hydrocarbon profile by contributing unique, diet-specific cues. We suggest that acquisition of common exogenous nestmate recognition cues from shared food sources may diminish aggression and promote fusion in neighboring colonies of the Argentine ant.
-
Effects of Interspecific Competition Between Two Urban Ant Species, Linepithema Humile and Monomorium minimum, on Toxic Bait Performance
Journal of economic entomology, 2005Co-Authors: Patricia Alder, Jules SilvermanAbstract:We evaluated the effects of interspeciÞc competition on ant bait performance with two urban pest ants, the Argentine ant, Linepithema Humile (Mayr), and the little black ant, Monomorium minimum (Buckley). In a laboratory study, the impact of a solid sulsuramid bait on M. minimum was diminished when L. Humile were present, whereas the presence of M. minimum reduced the perfor- mance of a liquid Þpronil bait against L. Humile. Argentine ants were not adversely affected by sulsuramid bait at any time, whereasM.minimum was unaffected by Þpronil bait until 14 d of exposure. In Þeld studies measuring diel foraging activity, M. minimum seemed to delay L. Humile foraging to food stations by 30 min during summer 2001. However, L. Humile subsequently recruited to food stations in very high numbers, thereby displacing M. minimum. L. Humile visited food stations over an entire 24-h period, whereasM.minimum was only observed visiting food stations during daylight hours. Adjusting the timing of bait placement in the Þeld may minimize any negative effects of interspeciÞc competition between these two species on toxic bait performance.
-
Hydrocarbon-released nestmate aggression in the Argentine ant, Linepithema Humile, following encounters with insect prey.
Comparative biochemistry and physiology. Part B Biochemistry & molecular biology, 2001Co-Authors: Dangsheng Liang, Gary J. Blomquist, Jules SilvermanAbstract:Argentine ants, Linepithema Humile, were attacked by their nestmates following contact with a particular prey item, the brown-banded cockroach, Supella longipalpa. Contact with prey, as brief as 2 min, provoked nestmate aggression. Argentine ants contaminated with hydrocarbons extracted from S. longipalpa also released nestmate aggression behavior similar to that released by the whole prey item, confirming the involvement of hydrocarbons. In contrast to S. longipalpa, little or no nestmate aggression was induced by other ant prey from diverse taxa. A comparison of prey hydrocarbon profiles revealed that all hydrocarbons of S. longipalpa were very long chain components with 33 or more carbons, while other prey had either less, or none, of the very long chain hydrocarbons of 33 carbons or greater. We identified the hydrocarbons of S. longipalpa and some new groups of long chain hydrocarbons of L. Humile. The majority of S. longipalpa hydrocarbons were 35 and 37 carbons in length with one to three methyl branches, and closely resembled two previously unidentified groups of compounds from L. Humile of similar chain length. The hydrocarbons of S. longipalpa and L. Humile were compared and their role in the Argentine ant nestmate recognition is discussed.
David A. Holway - One of the best experts on this subject based on the ideXlab platform.
-
The Introduced Argentine Ant (Linepithema Humile) on the California Channel Islands: Distribution and Patterns of Spread
Western North American Naturalist, 2018Co-Authors: Christina L. Boser, Ida Naughton, Korie Merrill, Robert N. Fisher, David A. HolwayAbstract:The Argentine ant (Linepithema Humile) is a widespread and abundant introduced species that disrupts ecosystems throughout its introduced range. This invader was inadvertently introduced to Santa Catalina, San Clemente, Santa Cruz, and San Nicolas Islands at various points during the past century but currently appears to be absent from the remaining Channel Islands. Multiple spatially disjunct infestations on each invaded island individually range in size from 427 ha and encompass a variety of habitats, including large areas that are entirely dominated by native perennial vegetation. The existence of multiple infestations on individual islands suggests that inadvertent introduction by humans serves as an important within-island dispersal mechanism. Multiyear surveys of individual infestations on San Clemente Island and Santa Cruz Island reveal approximately radial patterns of expansion (as a result of colony budding) away from the edge of each infestation. Rates of spread by budding on San Clemente Island range from 10 m/year to 57 m/year and are comparable to those on mainland California. Given the documented effects of Argentine ant invasions on Santa Cruz Island, the continued spread of the Argentine ant on the Channel Islands represents a serious environmental concern. Eradication programs underway on San Clemente and Santa Cruz Islands will hopefully result in island-wide elimination of this detrimental invader.
-
Argentine Ant (Linepithema Humile, Mayr) Eradication Efforts on San Clemente Island, California, USA
Western North American Naturalist, 2018Co-Authors: Korie C. Merrill, David A. Holway, Christina L. Boser, Cause Hanna, Ida Naughton, Dong-hwan Choe, Erin E. Wilson RankinAbstract:The Argentine ant, Linepithema Humile (Mayr), is a highly invasive ant species that has spread into urban, agricultural, and natural areas worldwide. The pervasive expansion of this species is detrimental both ecologically and economically, resulting in the allocation of vast amounts of resources for control. New efforts are underway to control the Argentine ant in ecologically sensitive habitats, such as those on the California Channel Islands. We tested the efficacy of thiamethoxam liquid bait at a concentration of 6 ppm on San Clemente Island, California, where the Argentine ant has spread into natural areas hosting protected endemic species. Applied by hand, helicopter, and ATV, hygroscopic polyacrylamide beads were used as a bait matrix to deliver the liquid bait (thiamethoxam and sucrose) for Argentine ant infestations at 5 sites (totaling 177 ha) on San Clemente Island. Treatments reduced the number of monitoring points at which the Argentine ant was detected 1 year posttreatment (17.91% vs. 3.65%), suggesting that these methods are a promising conservation tool. Continued monitoring to detect remaining infestations will be necessary for eventual eradication of the Argentine ant from San Clemente Island.
-
Relationships among native and introduced populations of the Argentine ant (Linepithema Humile) and the source of introduced populations
Molecular ecology, 2001Co-Authors: Neil D. Tsutsui, Andrew V. Suarez, David A. Holway, Ted J. CaseAbstract:The Argentine ant (Linepithema Humile) is a damaging invasive species that has become established in many Mediterranean-type ecosystems worldwide. To identify likely sources of introduced populations we examined the relationships among native Linepithema populations from Argentina and Brazil and introduced populations of L. Humile using mitochondrial cytochrome b sequence data and nuclear microsatellite allele frequencies. The mitochondrial phylogeny revealed that the populations in Brazil were only distantly related to both the introduced populations and the native populations in Argentina, and confirmed that populations in Brazil, previously identified as L. Humile, are likely a different species. The microsatellite-based analysis provided resolution among native and introduced populations of L. Humile that could not be resolved using the mitochondrial sequences. In the native range, colonies that were geographically close to one another tended to be genetically similar, whereas more distant colonies were genetically different. Most samples from the introduced range were genetically similar, although some exceptions were noted. Most introduced populations were similar to native populations from the southern Rio Parana and were particularly similar to a population from Rosario, Argentina. These findings implicate populations from the southern Rio Parana as the most likely source of introduced populations. Moreover, these data suggest that current efforts to identify natural enemies of the Argentine ant for biological control should focus on native populations in the southern Rio Parana watershed.
-
Distribution of the Argentine Ant (Linepithema Humile) in Northern California
Conservation Biology, 1995Co-Authors: David A. HolwayAbstract:The Argentine ant (Linepithema Humile Mayr, recently removed from the genus Iridomyrmex; Shattuck 1992) is a notorious tramp species. Argentine ants have been introduced throughout the world via human commerce and are most successful in Mediterranean and subtropical climates (Holldobler & Wilson 1990). Argentine ant invasions are ecologically devastating; they displace native ants (Erickson 1972) and other arthropods (Cole et al. 1992) and perturb ant-plant (Bond & Slingsby 1984) and ant-aphid (Way 1963) mutualisms. Although Argentine ants have been in California for at least 85 years (Woodworth 1908) and occur there widely (Knight & Rust 1990), relatively little is known about their invasion. Tremper (1976) and Ward (1987) conducted detailed surveys of ants in different portions of northern California and found L. Humile common in urban, agricultural, and disturbed riparian woodland habitats. In addition, both of these studies and Erickson (1972) documented little, if any, coexistence between L. Humile and epigeic (above-ground foraging) native ants. I repeated the surveys of Ward (1987) and Tremper (1976) to determine the degree to which Argentine ants are established and spreading in California. A large-scale, longitudinal survey such as this is important to clarify the temporal and spatial patterns of Argentine ant invasions in California and can be compared to such patterns elsewhere in the world.
Max Reuter - One of the best experts on this subject based on the ideXlab platform.
-
Loss of Wolbachia infection during colonisation in the invasive Argentine ant Linepithema Humile.
Heredity, 2004Co-Authors: Max Reuter, Jes S. Pedersen, Laurent KellerAbstract:Wolbachia are maternally inherited bacteria, which are very common in arthropods and nematodes. Wolbachia infection may affect host reproduction through feminisation, parthenogenesis, male-killing, cytoplasmic incompatibility and increased fecundity. Previous studies showing discrepancies between the phylogenies of Wolbachia and its arthropod hosts indicate that infection is frequently lost, but the causes of symbiont extinction have so far remained elusive. Here, we report data showing that colonisation of new habitats is a possible mechanism leading to the loss of infection. The presence and prevalence of Wolbachia were studied in three native and eight introduced populations of the Argentine ant Linepithema Humile. The screening shows that the symbiont is common in the three native L. Humile populations analysed. In contrast, Wolbachia was detected in only one of the introduced populations. The loss of infection associated with colonisation of new habitats may result from drift (founder effect) or altered selection pressures in the new habitat. Furthermore, a molecular phylogeny based on sequences of the Wolbachia wsp gene indicates that L. Humile has been infected by a single strain. Horizontal transmission of the symbiont may be important in ants as suggested by the sequence similarity of strains in the three genera Linepithema, Acromyrmex, and Solenopsis native from South and Central America.
-
Kin structure and queen execution in the Argentine ant Linepithema Humile
Journal of Evolutionary Biology, 2001Co-Authors: Max Reuter, Francois Balloux, Laurent Lehmann, Laurent KellerAbstract:Every spring, workers of the Argentine Ant Linepithema Humile kill a large proportion of queens within their nests. Although this behaviour inflicts a high energetic cost on the colonies, its biological significance has remained elusive so far. An earlier study showed that the probability of a queen being executed is not related to her weight, fecundity, or age. Here we test the hypothesis that workers collectively eliminate queens to which they are less related, thereby increasing their inclusive fitness. We found no evidence for this hypothesis. Workers of a nest were on average not significantly less related to executed queens than to surviving ones. Moreover, a population genetic analysis revealed that workers were not genetically differentiated between nests. This means that workers of a given nest are equally related to any queen in the population and that there can be no increase in average worker–queen relatedness by selective elimination of queens. Finally, our genetic analyses also showed that, in contrast to workers, queens were significantly genetically differentiated between nests and that there was significant isolation by distance for queens.