Publications (45)132.86 Total impact
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Article: Evidence for intersexual chemical mimicry in a dioecious plant.
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ABSTRACT: The dioecious Mediterranean fig, Ficus carica, displays a unique phenology in which males sometimes bloom synchronously with females (in summer), and sometimes not (in spring). Ficus carica is engaged in an obligatory mutualism with a specific pollinating wasp, which reproduces only within figs, localising them by their specific scents. We show that scents emitted by male figs show seasonal variation within individual trees. Scents of summer male figs resemble those of the co-flowering females, and are different from those of the same male trees in spring, when female figs are absent. These differences hold even if only compounds electrophysiologically active for pollinators are considered. The similar scents of summer males and females may explain why the rewardless females are still pollinated. These results offer a tractable model for future studies of intersexual chemical mimicry in mutualistic pollination interactions.Ecology Letters 07/2012; 15(9):978-85. · 17.56 Impact Factor -
Article: Floral scents: their roles in nursery pollination mutualisms
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ABSTRACT: Mutualisms are interspecies interactions in which each participant gains net benefits from interacting with its partner. In nursery pollination mutualisms, pollinators reproduce within the inflorescence they pollinate. In these systems, each partner depends directly on the other for its reproduction. Therefore, the signal responsible for partner encounter is crucial in these horizontally transmitted mutualisms, in which the association between specific partners must be renewed at each generation. As in many other interspecies interactions, chemical signals are suspected to be important in the functioning of these mutualisms. We synthesized and compared the published data available on the role of floral scents in the functioning of the 16 known independently evolved nursery pollination mutualisms. So far, attraction of pollinators to their specific hosts has been investigated in only seven of these systems, and the majority of the studies have been conducted on one of them, fig/fig wasp interactions. While such unevenness of the information limits the potential for meta-analysis, some patterns emerge from this review concerning the role of flower volatiles in maintaining the specificity of pollinator attraction, in signaling the appropriate phenological stage for pollinator visit, in attracting the pollinator toward the rewardless sex in dioecious plant species and in aiding the location and exploitation of resources by parasites and predators associated with these mutualisms. Finally, we highlight new perspectives on the evolution of signals in these diversified systems depending on the age and the degree of specificity of the interaction, and on the effect of phylogenetic inertia on the evolutionary dynamics of plant signals. KeywordsChemical mediation–Specific pollination–Pollination by deceit–Community ecology–Pollinator behavior–Evolutionary ecologyChemoecology 04/2012; 20(2):75-88. · 1.56 Impact Factor -
Article: Fine‐scale Population Genetic Structure of Two Dioecious Indian Keystone Species, Ficus hispida and Ficus exasperata (Moraceae)
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ABSTRACT: Although Ficus (Moraceae) is a keystone plant genus in the tropics, providing resources to many frugivorous vertebrates, its population genetic structure, which is an important determinant of its long-term survival, has rarely been investigated. We examined the population genetic structure of two dioecious fig species (Ficus hispida and Ficus exasperata) in the Indian Western Ghats using co-dominant nuclear microsatellite markers. We found high levels of microsatellite genetic diversity in both species. The regression slopes between genetic relationship coefficients (fij) and spatial distances were significantly negative in both species indicating that, on average, individuals in close spatial proximity were more likely to be related than individuals further apart. Mean parent–offspring distance (σ) calculated using these slopes was about 200 m in both species. This should be contrasted with the very long pollen dispersal distances documented for monoecious Ficus species. Nevertheless, overall population genetic diversity remained large suggesting immigrant gene flow. Further studies will be required to analyze broader scale patterns.Biotropica 04/2011; 43(3):309 - 316. · 2.23 Impact Factor -
Article: Insights into the biogeographical history of the Lower Guinea Forest Domain: evidence for the role of refugia in the intraspecific differentiation of Aucoumea klaineana.
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ABSTRACT: Determining the biogeographical histories of rainforests is central to our understanding of the present distribution of tropical biodiversity. Ice age fragmentation of central African rainforests strongly influenced species distributions. Elevated areas characterized by higher species richness and endemism have been postulated to be Pleistocene forest refugia. However, it is often difficult to separate the effects of history and of present-day ecological conditions on diversity patterns at the interspecific level. Intraspecific genetic variation could yield new insights into history, because refugia hypotheses predict patterns not expected on the basis of contemporary environmental dynamics. Here, we test geographically explicit hypotheses of vicariance associated with the presence of putative refugia and provide clues about their location. We intensively sampled populations of Aucoumea klaineana, a forest tree sensitive to forest fragmentation, throughout its geographical range. Characterizing variation at 10 nuclear microsatellite loci, we were able to obtain phylogeographic data of unprecedented detail for this region. Using Bayesian clustering approaches, we demonstrated the presence of four differentiated genetic units. Their distribution matched that of forest refugia postulated from patterns of species richness and endemism. Our data also show differences in diversity dynamics at leading and trailing edges of the species' shifting distribution. Our results confirm predictions based on refugia hypotheses and cannot be explained on the basis of present-day ecological conditions.Molecular Ecology 01/2011; 20(1):131-42. · 5.52 Impact Factor -
Article: Geographic variation of floral scent in a highly specialized pollination mutualism.
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ABSTRACT: Floral scents are important signals for communication between plants and pollinators. Several studies have focused on interspecific variation of these signals, but little is known about intraspecific variation in flower scent, particularly for species with wide geographic distributions. In the highly specific mutualism between Ficus species and their pollinating wasps, chemical mediation is crucial for partner encounter. Several studies show that scents, i.e. blends of volatiles, are species-specific, but no studies address interpopulation variation of scents in fig pollination mutualisms, which often have broad geographic distributions. In this study, using absorption/desorption headspace techniques, we analyzed variation in floral scent composition among three populations of each of two widely distributed Asian Ficus species. We identified more than 100 different volatile organic compounds, predominantly terpenes. In both species, significant differences were found between scent bouquets of East Asian and Indian populations. These differences are discussed in relation to geographical barriers that could disrupt gene exchange between these two areas, thereby isolating Indian populations from those of Eastern Asia.Phytochemistry 01/2011; 72(1):74-81. · 3.35 Impact Factor -
Article: A case study of modified interactions with symbionts in a hybrid mediterranean orchid.
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ABSTRACT: • Premise of the study: Most studies on orchid hybrids examine separately the effects of hybridization on interactions with pollinators or with mycorrhizal fungi. Here, we simultaneously investigated both interactions in the mediterranean food-deceptive Orchis simia, O. anthropophora, and their hybrid (O. ×bergonii) and tested a possible breakdown of coevolution using a multidisciplinary approach. • Methods: We compared leaf growth, seed viability, emitted scent, and mycorrhizal fungi (species and rate of infection) among these three taxa. • Key results: We show that leaf surface is greater in adult hybrids than in the parental species, suggesting a heterosis effect for vegetative growth. We demonstrate that flowers of the two parental species emit well-differentiated bouquets of volatile organic compounds, while hybrids emit larger quantities, accumulating most compounds of the two parental species. However, hybrids fail to attract pollinators and have a 10 times lower fruit set. We determined that closely related Tulasnellales are mycorrhizal in the three taxa, suggesting that the mycorrhizal partner does not impair hybrid survival. We propose an interpretative model for O. ×bergonii compared with its parents. • Conclusions: In hybrids, carbon resources normally devoted to reproduction may be reallocated to the mycorrhizal symbiosis as a result of the disruption of the pollination interaction in hybrids. Higher mycorrhizal infection may in turn enhance vegetative growth and scent emission. Such interplay between the two obligate biotic interactions yields new insights into hybridization among orchids.American Journal of Botany 08/2010; 97(8):1278-88. · 2.66 Impact Factor -
Article: Private channels in plant-pollinator mutualisms.
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ABSTRACT: Volatile compounds often mediate plant-pollinator interactions, and may promote specialization in plant-pollinator relationships, notably through private channels of unusual compounds. Nevertheless, the existence of private channels, i.e. the potential for exclusive communication via unique signals and receptors, is still debated in the literature. Interactions between figs and their pollinating wasps offer opportunities for exploring this concept. Several experiments have demonstrated that chemical mediation is crucial in ensuring the encounter between figs and their species-specific pollinators. Indeed, chemical messages emitted by figs are notably species- and developmental stage-specific, making them reliable cues for the pollinator. In most cases, the species-specificity of wasp attraction is unlikely to result from the presence of a single specific compound. Nevertheless, a recent paper on the role of scents in the interaction between Ficus semicordata and its pollinating wasp Ceratosolen gravelyi showed that a single compound, 4-methylanisole, is the main signal compound in the floral scent, and is sufficient by itself to attract the obligate pollinator. Mainly focusing on these results, we propose here that a floral scent can act as a private channel, attracting only the highly specific pollinator.Plant signaling & behavior 07/2010; 5(7):893-5. -
Article: Can chemical signals, responsible for mutualistic partner encounter, promote the specific exploitation of nursery pollination mutualisms? – The case of figs and fig wasps
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ABSTRACT: In nursery pollination mutualisms, where pollinators reproduce within the inflorescence they pollinate, floral scents often play a major role in advertizing host location and rewards for the pollinator. However, chemical messages emitted by the plant that are responsible for the encounter of mutualist partners can also be used by parasites of these mutualisms to locate their host. Each species of Ficus (Moraceae) is involved in an obligatory nursery pollination mutualism with usually one pollinating fig wasp (Hymenoptera: Chalcidoidea: Agaonidae). In this interaction, volatile compounds emitted by receptive figs are responsible for the attraction of their specific pollinator. However, a large and diverse community of non-pollinating chalcidoid wasps can also parasitize this mutualism. We investigated whether the chemical message emitted by figs to attract their pollinator can promote the host specificity of non-pollinating fig wasps. We analysed the volatile compounds emitted by receptive figs of three sympatric Ficus species, namely, Ficus hispida L., Ficus racemosa L., and Ficus tinctoria G. Forster, and tested the attraction of the pollinator of F. hispida (Ceratosolen solmsi marchali Mayr), and of one species of non-pollinating fig wasp [Philotrypesis pilosa Mayr (Hymenoptera: Chalcidoidea: Pteromalidae)] to scents emitted by receptive figs of these three Ficus species. Analysis of the volatile compounds emitted by receptive figs revealed that the three Ficus species could be clearly distinguished by their chemical composition. Behavioural bioassays performed in a Y-tube olfactometer showed that both pollinator and parasite were attracted only by the specific odour of F. hispida. These results suggest that the use by non-pollinating fig wasps of a specific chemical message produced by figs could limit host shifts by non-pollinating fig wasps.Entomologia Experimentalis et Applicata 02/2009; 131(1):46 - 57. · 1.53 Impact Factor -
Article: Colonization processes and the maintenance of genetic diversity: insights from a pioneer rainforest tree, Aucoumea klaineana.
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ABSTRACT: Despite recurrent episodes of range expansion and contraction, forest trees often harbour high genetic diversity. Studies of temperate forest trees suggest that prolonged juvenile phase and high pollen flow are the main factors limiting founder effects. Here, we studied the local colonization process of a pioneer rainforest tree in central Africa, Aucoumea klaineana. We identified 87% of parents among trees up to 20-25 years old and could thus compare direct parentage structure data with classical population genetics estimators. In this species, genetic diversity was maintained during colonization. The absence of founder effects was explained by (i) local random mating and (ii) local recruitment, as we showed that 75% of the trees in the close neighbourhood participated in the recruitment of new saplings. Long-distance pollen flow contributed little to genetic diversity: pollen and seed dispersal was mainly within stand (128 and 118 m, respectively). Spatial genetic structure was explained by aggregated seed dispersal rather than by mother-offspring proximity as assumed in classical isolation-by-distance models. Hence, A. klaineana presents a genetic diversity pattern typical of forest trees but does not follow the classical rules by which this diversity is generally achieved. We suggest that while high local genetic variability is of general importance to forest tree survival, the proximate mechanisms by which it is achieved may follow very different scenarios.Proceedings of the Royal Society B: Biological Sciences 07/2008; 275(1647):2171-9. · 5.41 Impact Factor -
Article: Small-scale spatial genetic structure in the Central African rainforest tree species Aucoumea klaineana: a stepwise approach to infer the impact of limited gene dispersal, population history and habitat fragmentation.
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ABSTRACT: Under the isolation-by-distance model, the strength of spatial genetic structure (SGS) depends on seed and pollen dispersal and genetic drift, which in turn depends on local demographic structure. SGS can also be influenced by historical events such as admixture of differentiated gene pools. We analysed the fine-scale SGS in six populations of a pioneer tree species endemic to Central Africa, Aucoumea klaineana. To infer the impacts of limited gene dispersal, population history and habitat fragmentation on isolation by distance, we followed a stepwise approach consisting of a Bayesian clustering method to detect differentiated gene pools followed by the analysis of kinship-distance curves. Interestingly, despite considerable variation in density, the five populations situated under continuous forest cover displayed very similar extent of SGS. This is likely due to an increase in dispersal distance with decreased tree density. Admixture between two gene pools was detected in one of these five populations creating a distinctive pattern of SGS. In the last population sampled in open habitat, the genetic diversity was in the same range as in the other populations despite a recent habitat fragmentation. This result may due to the increase of gene dispersal compensating the effect of the disturbance as suggested by the reduced extent of SGS estimated in this population. Thus, in A. klaineana, the balance between drift and dispersal may facilitate the maintenance of genetic diversity. Finally, from the strength of the SGS and population density, an indirect estimate of gene dispersal distances was obtained for one site: the quadratic mean parent-offspring distance, sigma(g), ranged between 210 m and 570 m.Molecular Ecology 05/2008; 17(8):2041-50. · 5.52 Impact Factor -
Article: Fig Wasps: A Staple Food for Ants on Ficus
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ABSTRACT: Mutualisms involve the exchange of resources and these resources attract exploiters and predators. Because predators may have a stronger effect either on mutualists or on exploiters, their net effect on the mutualism may be positive or negative. Ants and Ficus-associated wasps are a potential example. These wasps could represent sufficient food to ensure a permanent presence of predators. If this is the case then we may expect divergent selection (dependent on fig species) on traits facilitating or impeding ant predatory activity. Dioecious Ficus species in Brunei present the opportunity to determine whether presence of fig wasps on a tree ensures increased presence of ants because: (1) wasps are mainly present on male trees, thus allowing study of the effect of wasp abundance on ant presence; and (2) preliminary observations showed that ants present on trees were mainly predatory species that do not tend hemipterans. We show here, for several dioecious Ficus species, that many more ants were present on male trees than on female trees. Furthermore, these ants were mainly dominant predatory taxa that often nested in the male trees. Hence, wasps on male trees provide a sufficient resource in terms of quantity and reliability to ensure the continuous presence of dominant ants on the trees.ABSTRAKMutualisme melibatkan pertukaran sumber-sumber dan sumber-sumber ini memikat peneroka-peneroka dan pemangsa-pemangsa. Kerana pemangsa-pemangsa mungkin mempunyai kesan yang kuat pada mutualis-mutualis atau peneroka-peneroka, maka akibatnya terhadap mutualisme boleh menjadi positif atau negatif. Semut-semut dan penyengat-penyengat yang hidup rapat dengan Kayu ara adalah contoh yang berpotensi. Penyengat-penyengat ini boleh menjadi makanan yang mencukupi untuk mempastikan ketetapan kehadiran pemangsa-pemangsa. Jika ini sebenarnya berlaku maka kita boleh mengharapkan pemilihan penyibaran berbagai hala (bergantung pada spesis Kayu ara) yang menjurus kepada pemudahan atau penghalangan dan kegiatan pemangsaan. Spesis Kayu ara dioecius di Brunei merupakan satu peluang untuk menentukan samada kehadiran penyengat-penyengat Kayu ara pada pokok tersebut dapat menentukan bertambahnya kehadiran semut-semut kerana: 1) Penyengat-penyengat terutamanya didapati pada pokok-pokok jantan, maka itulah kajian diteruskan pada kesan penyengat yang banyak kepada kehadiran semut, and 2) Penelitian awal menunjukkan bahawa kehadiran semut-semut pada pokok-pokok tersebut adalah kebanyakannya spesis pemangsa yang tidak akan menjadi hemipteron. Ini menunjukkan bahawa bagi beberapa spesis Kayu ara dioecius kehadiran semut adalah lebih banyak lagi pada pokok-pokok jantan daripada yang terdapat di pokok-pokok betina. Malahan semut-semut tersebut adalah kebanyakannya taxa pemangsa yang dominan dan lazimnya bersarang pada pokok-pokok jantan. Oleh yang sedemikian, penyengat-penyengat yang berada di pokok-pokok jantan menyediakan sumber-sumber yang mencukupi berdasarkan pada jumlah dan keupayaan untuk mempastikan kehadiran semut-semut dominan berada di pokok-pokok tersebut secara berterusan.Biotropica 02/2008; 40(2):190 - 195. · 2.23 Impact Factor -
Article: Fungal sex as a private matter: odour signals in a specialized pollination-like insect-fungus mutualism.
New Phytologist 02/2008; 178(2):225-7. · 6.64 Impact Factor -
Article: Anthropogenic effects on population genetics of phytophagous insects associated with domesticated plants.
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ABSTRACT: The hypothesis of isolation by distance (IBD) predicts that genetic differentiation between populations increases with geographic distance. However, gene flow is governed by numerous factors and the correlation between genetic differentiation and geographic distance is never simply linear. In this study, we analyze the interaction between the effects of geographic distance and of wild or domesticated status of the host plant on genetic differentiation in the bean beetle Acanthoscelides obvelatus. Geographic distance explained most of the among-population genetic differentiation. However, IBD varied depending on the kind of population pairs for which the correlation between genetic differentiation and geographic distance was examined. Whereas pairs of beetle populations associated with wild beans showed significant IBD (P < 10(-4)), no IBD was found when pairs of beetle populations on domesticated beans were examined (P= 0.2992). This latter result can be explained by long-distance migrations of beetles on domesticated plants resulting from human exchanges of bean seeds. Beetle populations associated with wild beans were also significantly more likely than those on domesticated plants to contain rare alleles. However, at the population level, beetles on cultivated beans were similar in allelic richness to those on wild beans. This similarity in allelic richness combined with differences in other aspects of the genetic diversity (i.e., IBD, allelic diversity) is compatible with strongly contrasting effects of migration and drift. This novel indirect effect of human actions on gene flow of a serious pest of a domesticated plant has important implications for the spread of new adaptations such as resistance to pesticides.Evolution 12/2007; 61(12):2986-96. · 5.15 Impact Factor -
Article: Consequences of protecting flowers in a fig: a one‐way trip for pollinators?
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ABSTRACT: Fig trees (Ficus) have closed inflorescences. Closure is an efficient protection of flowers against non-specialist predators and harsh external environmental conditions. Each Ficus species is pollinated by a single insect species, an agaonid wasp, capable of forcing its way through a bract-covered pore, the ostiole, to gain access to the flowers. Figs also provide oviposition sites for the wasps. The fig/pollinator interaction is a classic example of mutualism. It has been widely assumed that, once pollinators have entered a fig, oviposited and pollinated, they die trapped within the fig. In this paper, we present observations under natural conditions and results of field experiments on three very different fig species (Ficus aurea Nutt., F. carica L. and F. microcarpa L.) showing that some pollinators do exit or try to exit from the fig after pollination and oviposition. Moreover, experimental results demonstrate that in at least one species (F. carica), the pollinator is able to oviposit successively in two different figs.The frequency of re-emergences from figs after pollination varies among species and this may be related to variations in pollination dynamics depending on environmental constraints such as the abundance of trees and tree phenology. Several factors that may favour pollinators that leave figs after pollination and oviposition are discussed. They include competition between pollinators for oviposition sites, and minimising of the risk of vertical transmission of parasites and pathogens.Journal of Biogeography 04/2007; 23(4):425 - 432. · 4.54 Impact Factor -
Article: Chemical mediation and niche partitioning in non-pollinating fig-wasp communities.
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ABSTRACT: 1. The parasitic chalcidoid wasps associated with the species-specific and obligatory pollination mutualisms between Ficus spp. and their agaonid wasp pollinators provide a good model to study the functional organization of communities. 2. However, communities of non-pollinating fig wasps (NPFWs) remain little characterized, and their functioning and evolutionary dynamics are still poorly understood. 3. We studied the communities of NPFWs associated with the monoecious F. racemosa and the dioecious F. hispida. Associated with these two fig species are a total of seven wasp species belonging to three genera. These species present contrasts in life history traits and in timing of oviposition. The species studied are thus broadly representative of the communities of NPFWs associated specifically with fig-pollinator mutualisms. 4. In our study systems, there is temporal segregation of oviposition time among members of NPFW communities. 5. We tested the role of volatile chemicals in the attraction of NPFWs associated with these two fig species, and tried to determine if chemical mediation can explain the organization of the communities. 6. We conducted odour choice tests using a Y-tube olfactometer. All the NPFWs studied were shown to use volatile chemicals produced by the fig to locate their host. Furthermore, the signals used by each species depended on the phenological stage of the fig they exploit. 7. Results demonstrated that the pattern of oviposition results from the utilization of volatile signals produced by figs that vary in their composition at different stages of fig development. Thus, chemical mediation allows resource partitioning in the NPFW communities associated with fig-pollinator mutualisms, and suggests hypotheses to explain coexistence in other parasite communities.Journal of Animal Ecology 04/2007; 76(2):296-303. · 4.94 Impact Factor -
Article: Complex interactions on fig trees: ants capturing parasitic wasps as possible indirect mutualists of the fig–fig wasp interaction
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ABSTRACT: Like other mutualisms, pollination mutualisms attract parasites, as well as opportunistic and specialist predators of the pollinators and parasites. These associated species influence the evolutionary dynamics of pairwise mutualisms. Predatory ants are frequent associates of pollination mutualisms, but their effects on the complex interactions between plants, pollinators and parasites have not yet been clearly established, even in the case of the well-described obligate interaction between figs and fig wasps. We attempted to quantify such effects for ants associated with three fig species, two dioecious (Ficus condensa [Bruneï], F. carica [France]) and one monoecious (F. racemosa [India]). In all these cases, ant presence on a fig tree strongly reduced the number of parasitic wasps on the figs. Experimental exclusion of ants resulted in an increase in the number of non-pollinating fig wasps on F. condensa and F. racemosa. Experimental ant supplementation led to a decrease in the number of non-pollinating fig wasps on F. carica. Moreover, on F. condensa, the level of reduction of the number of parasitic wasps depended on the number and identity of the ants. On F. carica, non-pollinating fig wasps even avoided trees occupied by the dominant predatory ant. The consistency of the effect of ants in these three cases, representing a geographically, ecologically, and taxonomically broad sample of figs, argues for the generality of the effect we observed. Because reduction of parasitism benefits the pollinator, ants may be considered as indirect mutualists of plants and pollinators in the network of complex interactions supported by fig trees.Oikos 04/2006; 113(2):344 - 352. · 3.06 Impact Factor -
Article: Phylogeographic support for horizontal gene transfer involving sympatric bruchid species.
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ABSTRACT: We report on the probable horizontal transfer of a mitochondrial gene, cytb, between species of Neotropical bruchid beetles, in a zone where these species are sympatric. The bruchid beetles Acanthoscelides obtectus, A. obvelatus, A. argillaceus and Zabrotes subfasciatus develop on various bean species in Mexico. Whereas A. obtectus and A. obvelatus develop on Phaseolus vulgaris in the Mexican Altiplano, A. argillaceus feeds on P. lunatus in the Pacific coast. The generalist Z. subfasciatus feeds on both bean species, and is sympatric with A. obtectus and A. obvelatus in the Mexican Altiplano, and with A. argillaceus in the Pacific coast. In order to assess the phylogenetic position of these four species, we amplified and sequenced one nuclear (28S rRNA) and two mitochondrial (cytb, COI) genes. Whereas species were well segregated in topologies obtained for COI and 28S rRNA, an unexpected pattern was obtained in the cytb phylogenetic tree. In this tree, individuals from A. obtectus and A. obvelatus, as well as Z. subfasciatus individuals from the Mexican Altiplano, clustered together in a unique little variable monophyletic unit. In contrast, A. argillaceus and Z. subfasciatus individuals from the Pacific coast clustered in two separated clades, identically to the pattern obtained for COI and 28S rRNA. An additional analysis showed that Z. subfasciatus individuals from the Mexican Altiplano also possessed the cytb gene present in individuals of this species from the Pacific coast. Zabrotes subfasciatus individuals from the Mexican Altiplano thus demonstrated two cytb genes, an "original" one and an "infectious" one, showing 25% of nucleotide divergence. The "infectious" cytb gene seems to be under purifying selection and to be expressed in mitochondria. The high degree of incongruence of the cytb tree with patterns for other genes is discussed in the light of three hypotheses: experimental contamination, hybridization, and pseudogenisation. However, none of these seem able to explain the patterns observed. A fourth hypothesis, involving recent horizontal gene transfer (HGT) between A. obtectus and A. obvelatus, and from one of these species to Z. subfasciatus in the Mexican Altiplano, seems the only plausible explanation. The HGT between our study species seems to have occurred recently, and only in a zone where the three beetles are sympatric and share common host plants. This suggests that transfer could have been effected by some external vector such as a eukaryotic or viral parasite, which might still host the transferred fragment. This article was reviewed by Eric Bapteste, Adam Eyre-Walker and Alexey Kondrashov.Biology Direct 02/2006; 1:21. · 4.02 Impact Factor -
Article: Consequences of a One-male Harem Reproductive System and Inbreeding in a Captive Group of Cercopithecus solatus
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ABSTRACT: In closed captive populations, where dispersal is not possible, kin recognition and behavioral avoidance are the only mechanisms by which closely related individuals can avoid inbreeding. In the absence of avoidance, a loss of genetic diversity is inevitable in successive generations.In the 1980s, the CIRMF in Gabon established a small breeding group of sun-tailed monkeys (Cercopithecus solatus) with 4 individuals, and subsequently 17 births have been registered. We aimed to describe via microsatellite genotyping the reproductive system in the colony of Cercopithecus solatus, to evaluate the loss of genetic diversity with succeeding generations, and to evaluate consequences of inbreeding depression on a measure of the lifespan reproductive success of females giving birth to inbred vs. noninbred offspring. During the 11-yr period for which data are available, only alpha males sired offspring, confirming a one-male social organization. They reproduced only during their period of tenure. Two of the 3 alpha males were responsible for all the infants born. Genetic diversity decreased and inbreeding coefficients increased with successive generations. Interbirth interval was increased following the birth of an inbred infant, indicating possible increased maternal costs of rearing inbred infants. Loss of genetic variability in this captive group of sun-tailed monkeys has led to significant inbreeding depression and demonstrates the importance of male-mediated gene flow in restricted one-male harem breeding groups.International Journal of Primatology 05/2005; 26(3):697-710. · 1.54 Impact Factor -
Article: Ancient and recent evolutionary history of the bruchid beetle, Acanthoscelides obtectus Say, a cosmopolitan pest of beans.
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ABSTRACT: Acanthoscelides obtectus Say is a bruchid species of Neotropical origin, and is specialized on beans of the Phaseolus vulgaris L. group. Since the domestication and diffusion of beans, A. obtectus has become cosmopolitan through human-mediated migrations and is now a major pest in bean granaries. Using phylogeographic methods applied to mitochondrial DNA (mtDNA) and nuclear microsatellite molecular markers, we show that the origin of this species is probably further south than Mesoamerica, as commonly thought. Our results also indicate that A. obtectus and its Mesoamerican sister species Acanthoscelides obvelatus, two morphologically close species differing principally in voltinism, speciated in allopatry: A. obtectus (multivoltine) arising in Andean America and A. obvelatus (univoltine) in Mesoamerica. In contrast to Mesoamerica where beans fruit once yearly, wild beans in Andean America fruit year-round, especially in regions showing little or no seasonality. In such habitats where resources are continuously present, multivoltinism is adaptive. According to existing hypotheses, multivoltinism in A. obtectus is a new adaptation that evolved after bean domestication. Our data suggest the alternative hypothesis that multivoltinism is an older trait, adapted to exploit the year-round fruiting of wild beans in relatively aseasonal habitats, and allowed A. obtectus to become a pest in bean granaries. This trait also permitted this species to disperse through human-mediated migrations associated with diffusion of domesticated beans. We also show that diversity of Old World A. obtectus populations can be quite well explained by a single colonization event about 500 bp. Human-mediated migrations appear not to be rare, as our results indicate a second more recent migration event from Andean America to Mexico.Molecular Ecology 05/2005; 14(4):1015-24. · 5.52 Impact Factor -
Article: Constraints on control: factors influencing reproductive success in male mandrills (Mandrillus sphinx)
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ABSTRACT: Over the last decade, paternity analysis using molecular markers has revealed that observed mating systems do not necessarily correlate with reproductive systems and thus cannot provide reliable information about male reproductive success (RS). This is especially true for primate species with a complex multimale-multifemale social organization, such as mandrills (Mandrillus sphinx). Using molecular markers for the measurement of individual RS and a comprehensive data set comprising 193 offspring from 27 birth cohorts over a 20-year period of sampling, we investigated the social, genetic, and demographic factors that may influence the probability of paternity by dominant male mandrills, living in a semi--free-ranging colony. We observed a significant skew in RS towards dominant males, with their probability of paternity increasing as the number of adult males in the group increased, and when they were closely related to subordinate adolescent males. Conversely, the probability of dominant males siring infants decreased when the number of simultaneously tumescent females increased. Fewer offspring were sired by dominant males when female partners were closely related to them and when the relatedness between dominant and subordinate adult males increased. These two last points suggests particularly that mechanisms of kin recognition are operating to avoid the costs of inbreeding and may also reflect the lower costs to dominant males of losing conception opportunities to more closely related subordinate adult males. This study is, to our knowledge, one of the first in primates to use an integrative approach and multivariate analysis to show that multiple factors are involved in determining the probability of paternity by dominant males. Copyright 2005.Behavioral Ecology. 01/2005; 16(3):614-623.
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- Ecological Entomology (2)
- Molecular Ecology (2)
- Ecology Letters (2)
Institutions
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2009
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University of KwaZulu-Natal
- School of Biological Sciences
Durban, KwaZulu-Natal, South Africa
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2001–2008
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Centre d'Ecologie Fonctionnelle et Evolutive
Montpellier, Languedoc-Roussillon, France
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2005–2007
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Université de Neuchâtel
- Laboratoire d'entomologie évolutive
Neuchâtel, NE, Switzerland
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1995–2007
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University of Miami
- Department of Biology
Coral Gables, FL, USA
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2002–2003
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French National Centre for Scientific Research
- Centre d'Ecologie Fonctionnelle et Evolutive
Paris, Ile-de-France, France
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