Local dispersal pathways during the invasion of the cactus moth, Cactoblastis cactorum, within North America and the Caribbean

Cactoblastis cactorum, a species of moth native to Argentina, feeds on several prickly pear cactus species (Opuntia) and has been successfully used as a biological control of invading Opuntia species in Australia, South Africa and native ruderal Opuntia species in some Caribbean islands. Since its introduction to the Caribbean its spread was uncontrolled, invading successfully Florida, Texas and Louisiana. Despite this long history of invasion, we are still far from understanding the factors determining the patterns of invasion of Cactoblastis in North America. Here, we explored three non-mutually exclusive explanations: a) a stepping stone model of colonization, b) long distance colonization due to hurricanes, and/or c) hitchhiking through previously reported commercial routes. Genetic diversity, genetic structure and the patterns of migration among populations were obtained by analyzing 10 nuclear microsatellite loci. Results revealed the presence of genetic structure among populations of C. cactorum in the invaded region and suggest that both marine commercial trade between the Caribbean islands and continental USA, as well as recurrent transport by hurricanes, explain the observed patterns of colonization. Provided that sanitary regulations avoiding humanmediated dispersal are enforced, hurricanes probably represent the most important agent of dispersal and future invasion to continental areas.Fil: Andraca Gómez, Guadalupe. Universidad Nacional Autónoma de México. Instituto de Ecología; MéxicoFil: Lombaert, Eric. Université Côte d'Azur; Francia. Centre National de la Recherche Scientifique; FranciaFil: Ordano, Mariano Andrés. Fundación Miguel Lillo; Argentina. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; ArgentinaFil: Pérez Ishiwara, Rubén. Universidad Nacional Autonoma de Mexico. Departamento de Ecología Evolutiva; MéxicoFil: Boege, Karina. Universidad Nacional Autonoma de Mexico. Departamento de Ecología Evolutiva; MéxicoFil: Domínguez, César A.. Universidad Nacional Autonoma de Mexico. Departamento de Ecología Evolutiva; MéxicoFil: Fornoni, Juan. Universidad Nacional Autonoma de Mexico. Departamento de Ecología Evolutiva; Méxic

A comparison of floral integration between selfing and outcrossing species: A meta-analysis

Background and Aims Floral integration is thought to be an adaptation to promote cross-fertilization, and it is often assumed that it increases morphological matching between flowers and pollinators, increasing the efficiency of pollen transfer. However, the evidence for this role of floral integration is limited, and recent studies have suggested a possible positive association between floral integration and selfing. Although a number of explanations exist to account for this inconsistency, to date there has been no attempt to examine the existence of an association between floral integration and mating system. This study hypothesized that if pollinator-mediated pollen movement among plants (outcrossing) is the main factor promoting floral integration, species with a predominantly outcrossing mating system should present higher levels of floral integration than those with a predominantly selfing mating system. Methods A phylogenetically informed meta-analysis of published data was performed in order to evaluate whether mating system (outcrossing vs. selfing) accounts for the variation in floral integration among 64 species of flowering plants. Morphometric floral information was used to compare intra-floral integration among traits describing sexual organs (androecium and gynoecium) and those corresponding to the perianth (calix and corolla). Key Results The analysis showed that outcrossing species have lower floral integration than selfing species. This pattern was caused by significantly higher integration of sexual traits than perianth traits, as integration of the latter group remained unchanged across mating categories. Conclusions The results suggest that the evolution of selfing is associated with concomitant changes in intra-floral integration. Thus, floral integration of sexual traits should be considered as a critical component of the selfing syndrome.Fil: Fornoni, Juan. Universidad Nacional Autónoma de México; MéxicoFil: Ordano, Mariano Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación Miguel Lillo; ArgentinaFil: Pérez Ishiwara, Rubén. Universidad Nacional Autónoma de México; MéxicoFil: Boege, Karina. Universidad Nacional Autónoma de México; MéxicoFil: Domínguez, César A.. Universidad Nacional Autónoma de México; Méxic

Evolutionary transition between bee pollination and hummingbird pollination in Salvia: Comparing means, variances and covariances of corolla traits

Covariation among traits can modify the evolutionary trajectory of complex structures. This process is thought to operate at a microevolutionary scale, but its long-term effects remain controversial because trait covariation can itself evolve. Flower morphology, and particularly floral trait (co)variation, has been envisioned as the product of pollinator-mediated selection. Available evidence suggests that major changes in pollinator assemblages may affect the joint expression of floral traits and their phenotypic integration. We expect species within a monophyletic lineage sharing the same pollinator type will show not only similarity in trait means but also similar phenotypic variance-covariance structures. Here, we tested this expectation using eighteen Salvia species pollinated either by bees or by hummingbirds. Our findings indicated a nonsignificant multivariate phylogenetic signal and a decoupling between means and variance-covariance phenotypic matrices of floral traits during the evolution to hummingbird pollination. Mean trait value analyses revealed significant differences between bee- and hummingbird-pollinated Salvia species although fewer differences were detected in the covariance structure between groups. Variance-covariance matrices were much more similar among bee- than hummingbird-pollinated species. This pattern is consistent with the expectation that, unlike hummingbirds, bees physically manipulate the flower, presumably exerting stronger selection pressures favouring morphological convergence among species. Overall, we conclude that the evolution of hummingbird pollination proceeded through different independent transitions. Thus, although the evolution of hummingbird pollination led to a new phenotypic optimum, the process involved the diversification of the covariance structure.Fil: Benitez-Vieyra, Santiago Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Pérez-Alquicira, Jessica. Instituto de Ecología; MéxicoFil: Sazatornil, Federico David. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Domínguez, César A.. Instituto de Ecología; MéxicoFil: Boege, Karina. Instituto de Ecología; MéxicoFil: Pérez Ishiwara, Rubén. Instituto de Ecología; MéxicoFil: Fornoni, Juan Enrique. Instituto de Ecología; Méxic

A potential invasion route of Cactoblastis cactorum within the Caribbean region matches historical hurricane trajectories

The cactus moth, Cactoblastis cactorum mainly distributed throughout central and northeastern Argentina was intentionally introduced in the Caribbean region in 1957 as a biological control agent of cacti species of the genus Opuntia. This moth invaded during the last 20–30 years the North American continent, threatening the major center of biodiversity of native Opuntia species. Although human induced and natural dispersal have been invocated to explain its expansion in the non-native distribution range, there is still no evidence to support natural dispersal. In particular, hurricanes are one of the major environmental factors affecting species dispersal in the region. In this study we used mitochondrial DNA to examine whether the spatial distribution of haplotype variation of C. cactorum is at least partially explained by hurricane trajectories within the Caribbean region. DNA sequences for the mitochondrial gene cytochrome oxidase I were obtained for a sample of 110 individuals from the Antillean islands. This information was combined with existing sequences in the GenBank for the same gene for the Caribbean and Florida (N = 132 sequences). Genetic diversity descriptors, a haplotypic network, a spatial analyses of molecular variance and a landscape genetic analysis of migration conditioned by hurricane tracks were conducted to test our hypothesis. Our results revealed a significant spatial grouping of haplotypes consistent with the more frequent hurricane trajectories in the Caribbean region. Significant isolation by distance conditioned by hurricane tracks was detected. Populations of Florida were genetically closer to those of Cuba than to the rest of the population sampled. Within the region, Cuba appears as a reservoir of genetic diversity increasing the risk of invasion to Mexico and the US. Despite commercial transportation of Opuntia promoted dispersal to Florida, our results support the hypothesis that natural disturbances such as hurricanes played a role dispersing this invasive insect. Future conservation programs of North American Opuntia species requires taking into account hurricane mediated dispersal events and permanent whole regional monitoring and international control policies to prevent future range expansions of C. cactorum.Fil: Andraca Gómez, Guadalupe. Universidad Nacional Autónoma de México; MéxicoFil: Ordano, Mariano Andrés. Fundación Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Boege, Karina. Universidad Nacional Autónoma de México; MéxicoFil: Domínguez, César A.. Universidad Nacional Autónoma de México; MéxicoFil: Piñero, Daniel. Universidad Nacional Autónoma de México; MéxicoFil: Pérez Ishiwara, Rubén. Universidad Nacional Autónoma de México; MéxicoFil: Pérez Camacho, Jacqueline. Ministerio de Ciencia, Tecnología y Medio Ambiente. Instituto de Ecología y Sistemática; CubaFil: Cañizares, Maikel. Ministerio de Ciencia, Tecnología y Medio Ambiente. Instituto de Ecología y Sistemática; CubaFil: Fornoni, Juan. Universidad Nacional Autónoma de México; Méxic