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Hervé Jourdan - One of the best experts on this subject based on the ideXlab platform.
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Cricket calling communities as an indicator of the invasive ant Wasmannia auropunctata in an insular biodiversity hotspot
Biological Invasions, 2018Co-Authors: A. Gasc, Jérôme Sueur, Jeremy Anso, Hervé Jourdan, L. Desutter-grandcolasAbstract:Invasive species are a major concern for the maintenance of ecosystem services and biodiversity but are difficult to mitigate. Upstream solutions to prevent their impact, including their detection, are needed. Wasmannia auropunctata, an invasive ant living in vagile supercolonies, is especially hard to track and is a major threat for tropical ecosystems and local animal communities. As part of such tropical communities, crickets are sensitive to ecological conditions, easy to collect, detectable and identifiable through their species-specific calls. Here, we evaluated the use of an acoustic community of crickets as an indicator of the presence of W. auropunctata in New Caledonia. We evaluated the dominance of the crickets in the soundscape, describe the cricket community structure and diversity along a shrubland to forest gradient, characterize these cricket communities structure and diversity in the light of ongoing invasion by W. auropunctata, and identify cricket species’ indicators of the invasion. Acoustic recordings collected on 24 sites were described using human-listening and spectrographic visualization. The results demonstrated a clear dominance of the cricket group in the New Caledonian nocturnal soundscapes. Each habitat harbored a specific acoustic cricket community related to specific environmental attributes including vegetation height, daily variation of humidity and temperature. The presence of W. auropunctata was significantly associated with a lower cricket acoustic activity and species richness at night. Of the 19 species detected, four nocturnal species were identified as indicator of non-invaded forests and preforests. This work supports the use of acoustic as an alternative method to detect invasion.
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Thermotolerance adaptation to human-modified habitats occurs in the native range of the invasive ant Wasmannia auropunctata before long-distance dispersal
Evolutionary Applications, 2013Co-Authors: Julien Foucaud, Hervé Jourdan, Olivier Rey, Benoit Facon, Anne Loiseau, Jérôme Orivel, Martin Kenne, Stéphanie Robert, Laurent Crespin, Paul Serge Mbenoun MasseAbstract:Key evolutionary events associated with invasion success are traditionally thought to occur in the introduced, rather than the native range of species. In the invasive ant Wasmannia auropunctata, however, a shift in reproductive system has been demonstrated within the native range, from the sexual non-dominant populations of natural habitats to the clonal dominant populations of human-modified habitats. Because abiotic conditions of human- modified habitats are hotter and dryer, we performed lab experiments on workers from a set of native and introduced populations, to investigate whether these ecological and genetic transitions were accompanied by a change in thermotolerance and whether such changes occurred before establishment in the introduced range. Thermotolerance levels were higher in native populations from human-modified habitats than in native populations from natural habitats, but were similar in native and introduced populations from human-modified habitats. Differences in thermotolerance could not be accounted for by differences in body size. A scenario based on local adaptation in the native range before introduction in remote areas represents the most parsimonious hypothesis to account for the observed phenotypic pattern. These findings highlight the importance of human land use in explaining major contemporary evolutionary changes.
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Ecologically heterogeneous populations of the invasive ant Wasmannia auropunctata within its native and introduced ranges
Ecological Entomology, 2009Co-Authors: Jérôme Orivel, Julien Foucaud, Hervé Jourdan, Denis Fournier, Julien Le Breton, Julien Grangier, Jacques H. C. Delabie, François‐xavier Andrès, Philippe Cerdan, Benoit FaconAbstract:The biology of most invasive species in their native geographical areas remains largely unknown. Such studies are, however, crucial in shedding light on the ecological and evolutionary processes underlying biological invasions. 2. The present study focuses on the little fire ant Wasmannia auropunctata, a species native to Central and South America that has been widely introduced and which has become invasive throughout the tropics. We characterise and compare several ecological traits of native populations in French Guiana with those in one of its introduced ranges, New Caledonia. 3. We found ecologically heterogeneous populations of W. auropunctata coexisting in the species' native geographical area. First, we found populations restricted to naturally perturbed areas (particularly floodplains) within the primary forest, and absent from the surrounding forest areas. These populations were characterised by low nest and worker densities. Second, we found dominant populations in recent anthropogenic areas (e.g. secondary forest or forest edge along road) characterised by high nest and worker densities, and associated with low ant species richness. The local dominance of W. auropunctata in such areas can be due to the displacement of other species (cause) or the filling-up of empty habitats unsuitable to other ants (effect). With respect to their demographic features and ant species richness, the populations of native anthropogenic habitats were to a large extent similar to the invasive populations introduced into remote areas. 4. The results point to the need for greater research efforts to better understand the ecological and demographic features of invasive species within their native ranges. © 2009 The Royal Entomological Society.
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Ecologically heterogeneous populations of the invasive ant Wasmannia auropunctata within its native and introduced ranges
Ecological Entomology, 2009Co-Authors: Jérôme Orivel, Julien Foucaud, Hervé Jourdan, Denis Fournier, Julien Le Breton, Julien Grangier, Jacques H. C. Delabie, Philippe Cerdan, François-xavier Andrès, Benoit FaconAbstract:The biology of most invasive species in their native geographical areas remains largely unknown. Such studies are, however, crucial in shedding light on the ecological and evolutionary processes underlying biological invasions.The present study focuses on the little fire ant 2. Wasmannia auropunctata, a species native to Central and South America that has been widely introduced and which has become invasive throughout the tropics. We characterise and compare several ecological traits of native populations in French Guiana with those in one of its introduced ranges, New Caledonia.We found ecologically heterogeneous populations of 3. W. auropunctata coexisting in the species’ native geographical area. First, we found populations restricted to naturally perturbed areas (particularly floodplains) within the primary forest, and absent from the surrounding forest areas. These populations were characterised by low nest and worker densities. Second, we found dominant populations in recent anthropogenic areas (e.g. secondary forest or forest edge along road) characterised by high nest and worker densities, and associated with low ant species richness. The local dominance of W. auropunctata in such areas can be due to the displacement of other species (cause) or the filling-up of empty habitats unsuitable to other ants (effect). With respect to their demographic features and ant species richness, the populations of native anthropogenic habitats were to a large extent similar to the invasive populations introduced into remote areas.4. The results point to the need for greater research efforts to better understand the ecological and demographic features of invasive species within their native ranges
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Intercontinental chemical variation in the invasive ant Wasmannia auropunctata (Roger) (Hymenoptera Formicidae): a key to the invasive success of a tramp species
Naturwissenschaften, 2005Co-Authors: Christine Errard, Hervé Jourdan, Jacques Delabie, Abraham HefetzAbstract:Unicoloniality emerges as a feature that characterizes successful invasive species. Its underlying mechanism is reduced intraspecific aggression while keeping interspecific competitiveness. To that effect, we present here a comparative behavioural and chemical study of the invasive ant Wasmannia auropunctata in parts of its native and introduced ranges. We tested the hypothesis that introduced populations (New Caledonia archipelago) have reduced intraspecific aggression relative to native populations (e.g., Ilhéus area, Brazil) and that this correlates with reduced variability in cuticular hydrocarbons (CHCs). As predicted, there was high intraspecific aggression in the Brazilian populations, but no intraspecific aggression among the New Caledonian populations. However, New Caledonian worker W. auropunctata remained highly aggressive towards ants of other invasive species. The chemical data corresponded with the behaviour. While CHCs of ants from the regions of Brazil diverged, the profiles of ants from various localities in New Caledonia showed high uniformity. We suggest that in New Caledonia W. auropunctata appears to behave as a single supercolony, whereas in its native range it acts as a multicolonial species. The uniformity of recognition cues in the New Caledonia ants may reflect a process whereby recognition alleles became fixed in the population, but may also be the consequence of a single introduction event and subsequent aggressive invasion of the ecosystem. Chemical uniformity coupled with low intraspecific but high interspecific aggression, lend credence to the latter hypothesis.
Abraham Hefetz - One of the best experts on this subject based on the ideXlab platform.
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Interspecific displacement mechanisms by the invasive little fire ant Wasmannia auropunctata
Biological Invasions, 2011Co-Authors: Merav Vonshak, Tamar Dayan, Abraham HefetzAbstract:Competition between invasive species and native ones in the new environment was found to be significant and to affect both animal and plant species. Invasive ants are notorious for displacing local ant species through competition. Competitive displacement of native species can occur through interference and or resource competition. However, for invasive ants, little is known about the relative importance of competitive displacement. We studied competitive interactions of the little fire ant, Wasmannia auropunctata, one of the most destructive invasive ant species, with two other ant species, Monomorium subopacum and Pheidole teneriffana. We compared the species’ foraging behavior and studied their aggressive interactions around food baits for the short (2 h) and long (21 days) term in the laboratory. Surprisingly we found that in short term experiments W. auropunctata had the poorest foraging abilities of the three species studied: it took the workers the longest to locate the bait and retrieve it; in addition they retrieved the lowest amount of food. When both W. auropunctata and M. subopacum were foraging the same bait, in the short term competition experiment, W. auropunctata workers did not defend the bait, and ceased foraging when encountered with competition. The long-term experiments revealed that W. auropunctata had the advantage in aggressive interactions over time; they eliminated seven of nine M. subopacum’s nests while consuming some of the workers and brood. According to our laboratory studies, W. auropunctata cannot be considered an extirpator species, unless it has a substantial numerical advantage, in contrast with previous assumptions. Otherwise it may behave as an insinuator species, i.e. the workers do not initiate aggression and by staying undetected they can continue foraging adjacent to dominant species.
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The little fire ant Wasmannia auropunctata: a new invasive species in the Middle East and its impact on the local arthropod fauna
Biological Invasions, 2009Co-Authors: Merav Vonshak, Tamar Dayan, Armin Ionescu-hirsh, Amnon Freidberg, Abraham HefetzAbstract:The little fire ant, Wasmannia auropunctata, probably arrived in Israel in ca. 1998 and was identified in 2005; this is the first record of this species from open areas outside the tropics and subtropics. It survives harsher conditions than in its native habitats, with minimal annual temperatures as low as 6°C, and 5–12 consecutive rainless months (under 15 mm rainfall per month). It is now known from 26 localities in Israel, mostly in irrigated gardens. As in other regions where they have invaded, these ants pose a serious threat to local biodiversity. At high densities they displaced almost all the local ant species sampled, affecting population abundances, species richness, and community structure. W. auropunctata seems to have a detrimental effect also on other ground arthropods, judging from the observed decline in spider and beetle abundances. We show here that this tropical species can pose a critical threat to local arthropods at a wider range of climatic conditions than was previously known.
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The interplay between genetic and environmental effects on colony insularity in the clonal invasive little fire ant Wasmannia auropunctata
Behavioral Ecology and Sociobiology, 2009Co-Authors: Merav Vonshak, Julien Foucaud, Arnaud Estoup, Tamar Dayan, Abraham HefetzAbstract:The little fire ant, Wasmannia auropunctata, constitutes one clonal supercolony throughout Israel, providing an opportunity to examine the effects of genotype versus environment on nestmate recognition. Intraspecific encounters among field-collected or among laboratory-maintained colonies were nonaggressive, but encounters between freshly collected and laboratory-maintained colonies were highly aggressive. Analyses of cuticular hydrocarbons revealed that freshly field-collected colonies had distinguishable profiles. Moreover, freshly collected colonies had profiles disparate from those of the same colonies after 4 months in the laboratory. These results indicate a strong interplay between genetic-based and environmentally based effects on the recognition cues. We propose that in the field the ants’ diet breadth is broad and consequently the incorporation of diet-borne substances is insufficient to mask the genetically determined cues. In the laboratory, however, the restricted diet promoted the incorporation of alien hydrocarbons at high levels, thus altering the genetically based cues to the point of alienation. These results shed a new light on the mechanisms by which environmental cues may affect label and/or template formation in ants.
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Intercontinental chemical variation in the invasive ant Wasmannia auropunctata (Roger) (Hymenoptera Formicidae): a key to the invasive success of a tramp species
Naturwissenschaften, 2005Co-Authors: Christine Errard, Hervé Jourdan, Jacques Delabie, Abraham HefetzAbstract:Unicoloniality emerges as a feature that characterizes successful invasive species. Its underlying mechanism is reduced intraspecific aggression while keeping interspecific competitiveness. To that effect, we present here a comparative behavioural and chemical study of the invasive ant Wasmannia auropunctata in parts of its native and introduced ranges. We tested the hypothesis that introduced populations (New Caledonia archipelago) have reduced intraspecific aggression relative to native populations (e.g., Ilhéus area, Brazil) and that this correlates with reduced variability in cuticular hydrocarbons (CHCs). As predicted, there was high intraspecific aggression in the Brazilian populations, but no intraspecific aggression among the New Caledonian populations. However, New Caledonian worker W. auropunctata remained highly aggressive towards ants of other invasive species. The chemical data corresponded with the behaviour. While CHCs of ants from the regions of Brazil diverged, the profiles of ants from various localities in New Caledonia showed high uniformity. We suggest that in New Caledonia W. auropunctata appears to behave as a single supercolony, whereas in its native range it acts as a multicolonial species. The uniformity of recognition cues in the New Caledonia ants may reflect a process whereby recognition alleles became fixed in the population, but may also be the consequence of a single introduction event and subsequent aggressive invasion of the ecosystem. Chemical uniformity coupled with low intraspecific but high interspecific aggression, lend credence to the latter hypothesis.
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Intercontinental chemical variation in the invasive ant Wasmannia auropunctata (Roger) (Hymenoptera Formicidae) : a key to the invasive success of a tramp species
Die Naturwissenschaften, 2005Co-Authors: Christine Errard, Hervé Jourdan, Jacques H. C. Delabie, Abraham HefetzAbstract:Unicoloniality emerges as a feature that characterizes successful invasive species. Its underlying mechanism is reduced intraspecific aggression while keeping interspecific competitiveness. To that effect, we present here a comparative behavioural and chemical study of the invasive ant Wasmannia auropunctata in parts of its native and introduced ranges. We tested the hypothesis that introduced populations (New Caledonia archipelago) have reduced intraspecific aggression relative to native populations (e.g., Ilheus area, Brazil) and that this correlates with reduced variability in cuticular hydrocarbons (CHCs). As predicted, there was high intraspecific aggression in the Brazilian populations, but no intraspecific aggression among the New Caledonian populations. However, New Caledonian worker W. auropunctata remained highly aggressive towards ants of other invasive species. The chemical data corresponded with the behaviour. While CHCs of ants from the regions of Brazil diverged, the profiles of ants from various localities in New Caledonia showed high uniformity. We suggest that in New Caledonia W. auropunctata appears to behave as a single supercolony, whereas in its native range it acts as a multicolonial species. The uniformity of recognition cues in the New Caledonia ants may reflect a process whereby recognition alleles became fixed in the population, but may also be the consequence of a single introduction event and subsequent aggressive invasion of the ecosystem. Chemical uniformity coupled with low intraspecific but high interspecific aggression, lend credence to the latter hypothesis.
Jacques H. C. Delabie - One of the best experts on this subject based on the ideXlab platform.
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Cytogenetic Studies on Workers of the Neotropical Ant Wasmannia auropunctata (Roger 1863) (Hymenoptera: Formicidae: Myrmicinae)
Annales de la Société entomologique de France (N.S.), 2011Co-Authors: Ana L B Souza, Cléa Dos Santos Ferreira Mariano, Jacques H. C. Delabie, Silvia Das Graças Pompolo, José Eduardo SerrãoAbstract:Abstract Wasmannia auropunctata is known as one of the worst invasive ants in the World. A cytogenetic study was conducted on two native populations from southeastern Bahia, Brazil. The analysis of the chromosomes observed in mitotic metaphases was made by a combination of methods: Giemsa conventional staining, chromomycin A3 (CMA3) and 4-6-diamidino-2-phenylindole (DAPI) fluorochrome staining, and acridine orange banding. The workers have all the karyotype 2n=32, with ten pairs of metacentric and six pairs of acrocentric chromosomes. One chromosome arm of the pair ten was positive for CMA3 and acridine orange, suggesting the occurrence of a nucleolar organizing region. This region is an interesting marker because is very conservative and seems to constitute an interesting specific taxonomic character. The pericentromeric region of many chromosomes was stained with DAPI, evidencing the occurrence of AT bases rich heterochromatin.
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Ecologically heterogeneous populations of the invasive ant Wasmannia auropunctata within its native and introduced ranges
Ecological Entomology, 2009Co-Authors: Jérôme Orivel, Julien Foucaud, Hervé Jourdan, Denis Fournier, Julien Le Breton, Julien Grangier, Jacques H. C. Delabie, François‐xavier Andrès, Philippe Cerdan, Benoit FaconAbstract:The biology of most invasive species in their native geographical areas remains largely unknown. Such studies are, however, crucial in shedding light on the ecological and evolutionary processes underlying biological invasions. 2. The present study focuses on the little fire ant Wasmannia auropunctata, a species native to Central and South America that has been widely introduced and which has become invasive throughout the tropics. We characterise and compare several ecological traits of native populations in French Guiana with those in one of its introduced ranges, New Caledonia. 3. We found ecologically heterogeneous populations of W. auropunctata coexisting in the species' native geographical area. First, we found populations restricted to naturally perturbed areas (particularly floodplains) within the primary forest, and absent from the surrounding forest areas. These populations were characterised by low nest and worker densities. Second, we found dominant populations in recent anthropogenic areas (e.g. secondary forest or forest edge along road) characterised by high nest and worker densities, and associated with low ant species richness. The local dominance of W. auropunctata in such areas can be due to the displacement of other species (cause) or the filling-up of empty habitats unsuitable to other ants (effect). With respect to their demographic features and ant species richness, the populations of native anthropogenic habitats were to a large extent similar to the invasive populations introduced into remote areas. 4. The results point to the need for greater research efforts to better understand the ecological and demographic features of invasive species within their native ranges. © 2009 The Royal Entomological Society.
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Ecologically heterogeneous populations of the invasive ant Wasmannia auropunctata within its native and introduced ranges
Ecological Entomology, 2009Co-Authors: Jérôme Orivel, Julien Foucaud, Hervé Jourdan, Denis Fournier, Julien Le Breton, Julien Grangier, Jacques H. C. Delabie, Philippe Cerdan, François-xavier Andrès, Benoit FaconAbstract:The biology of most invasive species in their native geographical areas remains largely unknown. Such studies are, however, crucial in shedding light on the ecological and evolutionary processes underlying biological invasions.The present study focuses on the little fire ant 2. Wasmannia auropunctata, a species native to Central and South America that has been widely introduced and which has become invasive throughout the tropics. We characterise and compare several ecological traits of native populations in French Guiana with those in one of its introduced ranges, New Caledonia.We found ecologically heterogeneous populations of 3. W. auropunctata coexisting in the species’ native geographical area. First, we found populations restricted to naturally perturbed areas (particularly floodplains) within the primary forest, and absent from the surrounding forest areas. These populations were characterised by low nest and worker densities. Second, we found dominant populations in recent anthropogenic areas (e.g. secondary forest or forest edge along road) characterised by high nest and worker densities, and associated with low ant species richness. The local dominance of W. auropunctata in such areas can be due to the displacement of other species (cause) or the filling-up of empty habitats unsuitable to other ants (effect). With respect to their demographic features and ant species richness, the populations of native anthropogenic habitats were to a large extent similar to the invasive populations introduced into remote areas.4. The results point to the need for greater research efforts to better understand the ecological and demographic features of invasive species within their native ranges
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Reproductive system, social organization, human disturbance and ecological dominance in native populations of the little fire ant, Wasmannia auropunctata
Molecular Ecology, 2009Co-Authors: Julien Foucaud, Anne Loiseau, Denis Fournier, Jérôme Orivel, Julien Le Breton, Jacques H. C. Delabie, Philippe Cerdans, Arnaud EstoupAbstract:The invasive ant species Wasmannia auropunctata displays both ecologically dominant and non-dominant populations within its native range. Three factors could theoretically explain the ecological dominance of some native populations of W. auropunctata: (i) its clonal reproductive system, through demographic and ⁄ or adaptive advantages; (ii) its unicolonial social organization, through lower intraspecific and efficient interspecific competition; (iii) the human disturbance of its native range, through the modification of biotic and abiotic environmental conditions. We used microsatellite markers and behavioural tests to uncover the reproductive modes and social organization of dominant and non-dominant native populations in natural and human-modified habitats. Microsatellite and mtDNA data indicated that dominant and non-dominant native populations (supercolonies as determined by aggression tests) of W. auropunctata did not belong to different evolutionary units. We found that the reproductive system and the social organization are neither necessary nor sufficient to explain W. auropunctata ecological dominance. Dominance rather seems to be set off by unknown ecological factors altered by human activities, as all dominant populations were recorded in human-modified habitats. The clonal reproductive system found in some populations of W. auropunctata may however indirectly contribute to its ecological dominance by allowing the species to expand its environmental niche, through the fixation over time of specific combinations of divergent male and female genotypes. Unicoloniality may rather promote the range expansion of already dominant populations than actually trigger ecological dominance. The W. auropunctata model illustrates the strong impact of human disturbance on species’ ecological features and the adaptive potential of clonal reproductive systems.
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Genetic variability of native populations of Wasmannia Forel (Hymenoptera: Formicidae) and their biogeographical implications.
Neotropical entomology, 2009Co-Authors: Ana L B Souza, José Eduardo Serrão, Mara Garcia Tavares, Jacques H. C. DelabieAbstract:Wasmannia auropunctata (Roger) and Wasmannia rochai Forel are economically important ants in the Southeast and Southwest regions of Bahia State, Brazil. Randomly Amplified Polymorphic DNA (RAPD) markers were used to distinguish and analyze the genetic variability of populations of both species from Ilheus, Jequie, BA and French Guyana. The genetic distances among W. auropunctata and W.rochai populations (55.8-71.4%) suggest genetic differentiation among them. Wasmannia auropunctata populations from sugarcane and banana plantations in Jequie were the most distant genetically (30.1-46.3%) and may represent populations restricted to isolated fragments. The high genetic distances among W. auropunctata populations from CEPLAC experimental areas, in Ilheus (26.8-34.6%) and the other populations from Ilheus (23.3-40.8%), suggest a multicolonial structure of W. auropunctata in southeast Bahia. The genetic proximity among the W. auropunctata populations from cocoa (14.1%) and coconut plantations (18.5%) in Ilheus with the populations from the French Guyanan forests suggest that there was recent and large expansion of populations derived from a single population, that are today distributed in habitats with similar environmental characteristics. The high polymorphism and the estimated heterozygosity values for the two species suggest that we studied native W. auropunctata and W.rochai populations.
Julien Foucaud - One of the best experts on this subject based on the ideXlab platform.
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Androgenesis is a maternal trait in the invasive ant Wasmannia auropunctata.
Proceedings. Biological sciences, 2013Co-Authors: Olivier Rey, Julien Foucaud, Benoit Facon, Anne Loiseau, Arnaud EstoupAbstract:Androgenesis is the production of an offspring containing exclusively the nuclear genome of the fathering male via the maternal eggs. This unusual mating system is generally considered a male trait, giving to androgenetic males a substantial fitness advantage over their sexually reproducing relatives. We here provide the first empirical study of the evolutionary outcomes of androgenesis in a haplo-diploid organism: the invasive ant Wasmannia auropunctata. Some of the populations of this species have a classical haplo-diploid sexual mating system. In other populations, females and males are produced through parthenogenesis and androgenesis, respectively, whereas workers are produced sexually. We conducted laboratory reciprocal-cross experiments with reproductive individuals from both types of populations and analysed their progenies with genetic markers, to determine the respective contribution of males and females to the production of androgenetic males. We found that androgenesis was a parthenogenetic female trait. A population genetic study conducted in natura confirmed the parthenogenetic female origin of androgenesis, with the identification of introgression events of sexual male genotypes into androgenetic/parthenogenetic lineages. We argue that by producing males via androgenesis, parthenogenetic queen lineages may increase and/or maintain their adaptive potential, while maintaining the integrity of their own genome, by occasionally acquiring new male genetic material and avoiding inbreeding depression within the sexually produced worker cast.
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Thermotolerance adaptation to human-modified habitats occurs in the native range of the invasive ant Wasmannia auropunctata before long-distance dispersal
Evolutionary Applications, 2013Co-Authors: Julien Foucaud, Hervé Jourdan, Olivier Rey, Benoit Facon, Anne Loiseau, Jérôme Orivel, Martin Kenne, Stéphanie Robert, Laurent Crespin, Paul Serge Mbenoun MasseAbstract:Key evolutionary events associated with invasion success are traditionally thought to occur in the introduced, rather than the native range of species. In the invasive ant Wasmannia auropunctata, however, a shift in reproductive system has been demonstrated within the native range, from the sexual non-dominant populations of natural habitats to the clonal dominant populations of human-modified habitats. Because abiotic conditions of human- modified habitats are hotter and dryer, we performed lab experiments on workers from a set of native and introduced populations, to investigate whether these ecological and genetic transitions were accompanied by a change in thermotolerance and whether such changes occurred before establishment in the introduced range. Thermotolerance levels were higher in native populations from human-modified habitats than in native populations from natural habitats, but were similar in native and introduced populations from human-modified habitats. Differences in thermotolerance could not be accounted for by differences in body size. A scenario based on local adaptation in the native range before introduction in remote areas represents the most parsimonious hypothesis to account for the observed phenotypic pattern. These findings highlight the importance of human land use in explaining major contemporary evolutionary changes.
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Distribution of endosymbiotic reproductive manipulators reflects invasion process and not reproductive system polymorphism in the little fire ant Wasmannia auropunctata
PLoS ONE, 2013Co-Authors: Olivier Rey, Arnaud Estoup, Benoit Facon, Anne Loiseau, Alexandre Aebi, Olivier Duron, Fabrice Vavre, Julien FoucaudAbstract:Endosymbiotic reproductive manipulators may have drastic effects on the ecological and evolutionary dynamics of their hosts. The prevalence of these endosymbionts reflects both their ability to manipulate their hosts and the history of the host populations. The little fire ant Wasmannia auropunctata displays a polymorphism in both its reproductive system (sexual versus clonal populations) and the invasive status of its populations (associated to a habitat shift). We first screened for the presence of a diverse array of reproductive parasites in sexual and clonal populations of W. auropunctata, as a means to investigate the role of endosymbionts in reproductive phenotypes. Wolbachia was the only symbiont found and we then focused on its worldwide distribution and diversity in natural populations of W. auropunctata. Using a multilocus scheme, we further characterized the Wolbachia strains present in these populations. We found that almost all the native sexual populations and only a few clonal populations are infected by Wolbachia. The presence of similar Wolbachia strains in both sexual and clonal populations indicates that they are probably not the cause of the reproductive system polymorphism. The observed pattern seems rather associated to the invasion process of W. auropunctata. In particular, the observed loss of Wolbachia in clonal populations, that recurrently emerged from sexual populations, likely resulted from natural heat treatment and/or relaxed selection during the shift in habitat associated to the invasion process.
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The interplay between genetic and environmental effects on colony insularity in the clonal invasive little fire ant Wasmannia auropunctata
Behavioral Ecology and Sociobiology, 2009Co-Authors: Merav Vonshak, Julien Foucaud, Arnaud Estoup, Tamar Dayan, Abraham HefetzAbstract:The little fire ant, Wasmannia auropunctata, constitutes one clonal supercolony throughout Israel, providing an opportunity to examine the effects of genotype versus environment on nestmate recognition. Intraspecific encounters among field-collected or among laboratory-maintained colonies were nonaggressive, but encounters between freshly collected and laboratory-maintained colonies were highly aggressive. Analyses of cuticular hydrocarbons revealed that freshly field-collected colonies had distinguishable profiles. Moreover, freshly collected colonies had profiles disparate from those of the same colonies after 4 months in the laboratory. These results indicate a strong interplay between genetic-based and environmentally based effects on the recognition cues. We propose that in the field the ants’ diet breadth is broad and consequently the incorporation of diet-borne substances is insufficient to mask the genetically determined cues. In the laboratory, however, the restricted diet promoted the incorporation of alien hydrocarbons at high levels, thus altering the genetically based cues to the point of alienation. These results shed a new light on the mechanisms by which environmental cues may affect label and/or template formation in ants.
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Ecologically heterogeneous populations of the invasive ant Wasmannia auropunctata within its native and introduced ranges
Ecological Entomology, 2009Co-Authors: Jérôme Orivel, Julien Foucaud, Hervé Jourdan, Denis Fournier, Julien Le Breton, Julien Grangier, Jacques H. C. Delabie, François‐xavier Andrès, Philippe Cerdan, Benoit FaconAbstract:The biology of most invasive species in their native geographical areas remains largely unknown. Such studies are, however, crucial in shedding light on the ecological and evolutionary processes underlying biological invasions. 2. The present study focuses on the little fire ant Wasmannia auropunctata, a species native to Central and South America that has been widely introduced and which has become invasive throughout the tropics. We characterise and compare several ecological traits of native populations in French Guiana with those in one of its introduced ranges, New Caledonia. 3. We found ecologically heterogeneous populations of W. auropunctata coexisting in the species' native geographical area. First, we found populations restricted to naturally perturbed areas (particularly floodplains) within the primary forest, and absent from the surrounding forest areas. These populations were characterised by low nest and worker densities. Second, we found dominant populations in recent anthropogenic areas (e.g. secondary forest or forest edge along road) characterised by high nest and worker densities, and associated with low ant species richness. The local dominance of W. auropunctata in such areas can be due to the displacement of other species (cause) or the filling-up of empty habitats unsuitable to other ants (effect). With respect to their demographic features and ant species richness, the populations of native anthropogenic habitats were to a large extent similar to the invasive populations introduced into remote areas. 4. The results point to the need for greater research efforts to better understand the ecological and demographic features of invasive species within their native ranges. © 2009 The Royal Entomological Society.
Luis A Calcaterra - One of the best experts on this subject based on the ideXlab platform.
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Linking thermo-tolerances of the highly invasive ant, Wasmannia auropunctata, to its current and potential distribution
Biological Invasions, 2019Co-Authors: Carolina Coulin, Gerardo J. Vega, Lucila Chifflet, Luis A Calcaterra, Pablo E. SchilmanAbstract:Species distribution models based on the correlation of bioclimatic variables and presence spatial data-points are useful for recognizing species habitat suitability. However, they have limitations in predicting the introduced ranges of invasive species that could be overcome by using species eco-physiological traits. By combining bioclimatic variables with thermal tolerance plasticity of the highly invasive little fire ant, Wasmannia auropunctata , we intend to better understand the mechanism underlying its current and future distributions. To this end, we performed: (1) laboratory physiological experiments to assess thermal tolerances (CTmin and CTmax) and evaluate the effect of acclimation (laboratory) and acclimatization (nature) on these variables, (2) behavioral foraging observations in the field, (3) a correlative and a simple mechanistic SDM. Briefly, physiological results showed a modulation of the CTmax and CTmin by different acclimation temperatures and by seasonal thermal acclimatization. In the field, worker foraging activity begins at environmental temperatures just above (less than 1 °C) the lowest CTmin recorded in the laboratory. At the global scale, CTmin constitutes a key physiological trait that, when linked with the minimum temperature of the coldest month, could explain the southernmost limit of W. auropunctata native distribution and its physiological capacity to expand in the Mediterranean region. The eco-physiological approach carried out here may help explain the current distribution and predict potential spread of populations when there is no certain information about the whole distribution of the species or under a changing environment. The latter is of great importance especially when analyzing invasive insects, pests or disease vectors.
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Southern expansion of the invasive ant Wasmannia auropunctata within its native range and its relation with clonality and human activity.
PloS one, 2018Co-Authors: Lucila Chifflet, Olivier Rey, Noelia Verónica Guzmán, Viviana A. Confalonieri, Luis A CalcaterraAbstract:The little fire ant Wasmannia auropunctata, native to the Neotropics, has become a serious pest worldwide over the past 100 years. It was originally distributed from Mexico to northern Argentina and new evidence suggests a recent southern range expansion during the last 60 years reaching central Argentina. This supercolonial ant species has a polymorphic reproductive system. Some populations, mostly found in undisturbed natural environments, are characterised by a classical sexual haplodiploid reproductive system. In other populations, which mainly occur in human-modified habitats, diploid queens and haploid males are produced clonally while workers are produced sexually. Here we studied the association between the recent southern range expansion of W. auropunctata in relation to human activity and clonality. We carried out an extensive survey within the southern limit of the species' native distribution and characterised the type of habitat where populations were found. Moreover, we genetically determined the type of reproductive system in 35 populations by genotyping at 12 microsatellite loci a total of 191 reproductive individuals (i.e. queens and/or males). Clonality was the most common reproductive system, occurring in 31 out of 35 populations analysed. All the populations found in the recently colonised area in central Argentina were clonal and established in human-modified habitats, suggesting that clonality together with human activity might have facilitated the southwards expansion of W. auropunctata.
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Evolutionary history of the little fire ant Wasmannia auropunctata before global invasion: inferring dispersal patterns, niche requirements and past and present distribution within its native range.
Journal of evolutionary biology, 2016Co-Authors: Lucila Chifflet, Luis A Calcaterra, Olivier Rey, Peter A. Follett, Marcela Silvina Rodriguero, P. A. Dinghi, Fabricio Beggiato Baccaro, Jorge L. P. Souza, Viviana A. ConfalonieriAbstract:The evolutionary history of invasive species within their native range may involve key processes that allow them to colonize new habitats. Therefore, phylogeographic studies of invasive species within their native ranges are useful to understand invasion biology in an evolutionary context. Here we integrated classical and Bayesian phylogeographic methods using mitochondrial and nuclear DNA markers with a palaeodistribution modelling approach, to infer the phylogeographic history of the invasive ant Wasmannia auropunctata across its native distribution in South America. We discuss our results in the context of the recent establishment of this mostly tropical species in the Mediterranean region. Our Bayesian phylogeographic analysis suggests that the common ancestor of the two main clades of W. auropunctata occurred in central Brazil during the Pliocene. Clade A would have differentiated northward and clade B southward, followed by a secondary contact beginning about 380,000 years ago in central South America. There were differences in the most suitable habitats among clades when considering three distinct climatic periods, suggesting that genetic differentiation was accompanied by changes in niche requirements, clade A being a tropical lineage and clade B a subtropical and temperate lineage. Only clade B reached more southern latitudes, with a colder climate than that of northern South America. This is concordant with the adaptation of this originally tropical ant species to temperate climates prior to its successful establishment in the Mediterranean region. This study highlights the usefulness of exploring the evolutionary history of invasive species within their native ranges to better understand biological invasions.
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Acute Exposure to Low-Dose Radiation Disrupts Reproduction and Shortens Survival of Wasmannia auropunctata (Hymenoptera: Formicidae) Queens
Journal of economic entomology, 2012Co-Authors: Luis A Calcaterra, Carolina Coulin, Juan A. Briano, Peter A. FollettAbstract:Irradiation is a postharvest quarantine treatment option to control ants and other hitchhiker pests on fresh horticultural products exported from Hawaii. The radiotolerance of the invasive little fire ant, Wasmannia auropunctata (Roger) (Hymenoptera: Formicidae: Myrmicinae), was studied to determine a dose sufficient for its control. Queens from each of five laboratory microcolonies started from five geographic locations in Argentina were irradiated at 20, 50, 70, or 100 Gy or left untreated as controls and then followed for 13 wk to observe colony growth. In general, queen survivorship, and the number of eggs, larvae, and pupae observed in the microcolonies decreased with increasing irradiation dose. In the 50-, 70-, and 100-Gy treatments, the number of eggs observed was reduced by 68, 66, and 76%, respectively, compared with untreated control microcolonies. The number of larvae in the 50-, 70-, and, 100-Gy treatments was reduced by 99.6%, and only one pupa was observed in the 50-Gy treatment and none in the 70- and 100-Gy treatments during the 13-wk experiment. Queens in the 100-Gy treatment had significantly reduced longevity compared with queens in the other treatments. Radiation doses ≥70 Gy stopped reproduction in W. auropunctata queens and should be sufficient as a phytosanitary treatment. Information from additional invasive ants in Myrmicinae and other subfamilies is needed before recommending a generic irradiation treatment for ants.