Temporal pattern of africanization in a feral honeybee population from Texas inferred from mitochondrial DNA

The invasion of Africanized honeybees (Apis mellifera L.) in the Americas provides a window of opportunity to study the dynamics of secondary contact of subspecies of bees that evolved in allopatry in ecologically distinctive habitats of the Old World. We report here the results of an 11-year mitochondrial DNA survey of a feral honeybee population from southern United States (Texas). The mitochondrial haplotype (mitotype) frequencies changed radically during the 11-year study period. Prior to immigration of Africanized honeybees, the resident population was essentially of eastern and western European maternal ancestry. Three years after detection of the first Africanized swarm there was a mitotype turnover in the population from predominantly eastern European to predominantly A. m. scutellata (ancestor of Africanized honeybees). This remarkable change in the mitotype composition coincided with arrival of the parasitic mite Varroa destructor, which was likely responsible for severe losses experienced by colonies of European ancestry. From 1997 onward the population stabilized with most colonies of A. m. scutellata maternal origin.PRODEP II - Medida 5/Acção 5.

Identification of africanized honey bee (Hymenoptera: apidae) mitochondrial DNA: validation of a rapid polymerase chain reaction-based assay

Polymerase chain reaction (PCR)-ampliÞed mitochondrialDNA(mtDNA)assays have been used in studies of the Africanization process in neotropical feral and managed honey bee populations. The approach has been adopted, in conjunction with morphometric analysis, to identify Africanized bees for regulatory purposes in the United States such as in California. In this study, 211 Old World colonies, representing all known introduced subspecies in the United States, and 451 colonies from non-Africanized areas of the southern United States were screened to validate a rapid PCR-based assay for identiÞcation of Africanized honey bee mtDNA. This PCR-based assay requires a single enzyme digestion (BglII) of a single PCR-ampliÞed segment of the cytochrome b gene. The BglII polymorphism discriminates the mitochondrial haplotype (mitotype) of Apis mellifera scutellata L. (ancestor of Africanized bees) from that of A. m. mellifera, A. m. caucasia, A. m. ligustica, A. m. carnica, A. m. lamarcki, A. m. cypria, A. m. syriaca, and some A. m. iberiensis, but not from that of A. m. intermissa and some A. m. iberiensis. Nonetheless, given the very low frequency ( 1%) of African non-A. m. scutellata mitotype present before arrival of Africanized bees in the United States, cytochrome b/BglII assay can be used to identify maternally Africanized bees with a high degree of reliability

A landscape genetics approach to unravel the complex evolutionary history of the Iberian honey bee hybrid zone

While landscape genetics is in its infancy, it is a rapidly growing research field in part owing to the increasing availability of powerful molecular and analytical tools. By integrating landscape ecology, spatial statistics and population genetics, landscape genetics is allowing an unprecedented understanding of the microevolutionary processes shaping genetic variation, which has important implications for the advance of ecological and evolutionary knowledge. The Iberian honey bee provides a great model system to address evolutionary questions using a landscape genetics framework. First, previous studies suggest that the Iberian honey bee has a hybrid origin and hybrid zones have been favored by evolutionary biologists as powerful natural laboratories to study evolutionary processes. Second, with the publication of the honey bee genome and development of high‐density SNP markers, powerful tools are now available to dissect the relative importance of neutral and adaptive forces in shaping the Iberian honey bee hybrid zone, a goal of central importance as it leads to more robust inferences of demographic history and to identification of adaptive divergence. Herein, we will present an ongoing research project on the Iberian honey bee hybrid zone where the tools of landscape genetics and population genomics will be combined to unravel the challenging evolutionary history of the Iberian honey bee

Signatures of selection in the Iberian honey bee: a genome wide approach using single nucleotide polymorphisms (SNPs)

Dissecting genome-wide (expansions, contractions, admixture) from genome-specific effects (selection) is a goal of central importance in evolutionary biology because it leads to more robust inferences of demographic history and to identification of adaptive divergence. The publication of the honey bee genome and the development of high-density SNPs genotyping, provide us with powerful tools, allowing us to identify signatures of selection in the honey bee genome. These signatures will be an important first step towards understanding the transition of genotype into phenotype and the basis of adaptive divergence. The Iberian Peninsula harbours the greatest honey bee genetic diversity and complexity in Europe. The challenge of deciphering the mechanisms underlying such complexity has led to numerous morphological and molecular marker-based surveys of the Iberian honey bee. Yet, in spite of the numerous studies, the evolutionary processes underlying patterns of Iberian honey bee genetic diversity remain poorly understood. The evolutionary process in the Iberian Peninsula has been dynamic and the genetic consequences are too complex to be addressed piecemeal, using few markers with unknown or poorly known linkage relationships. Accordingly, in 2010 more than 650 honey bee colonies were sampled across latitudinal and longitudinal clines in the Iberian Peninsula. The 650 honey bee samples were genotyped for 1536 SNPs – all equally distributed across the honey bee genome and all with known linkage relationships, based on the latest honey bee genome assembly. Herein we show the preliminary results of this genotyping, focusing on an Iberian honey bee genome inquiry on recent selective sweeps. We provide new insights into the evolutionary processes shaping the Iberian honey bee patterns

Signatures of selection in the Iberian honey bee: a genome wide approach using single nucleotide polymorphisms (SNPs)

Dissecting genome-wide (expansions, contractions, admixture) from genome-specific effects (selection) is a goal of central importance in evolutionary biology because it leads to more robust inferences of demographic history and to identification of adaptive divergence. The publication of the honey bee genome and the development of high-density SNPs genotyping, provide us with powerful tools, allowing us to identify signatures of selection in the honey bee genome. These signatures will be an important first step towards understanding the transition of genotype into phenotype and the basis of adaptive divergence. The Iberian Peninsula harbours the greatest honey bee genetic diversity and complexity in Europe. The challenge of deciphering the mechanisms underlying such complexity has led to numerous morphological and molecular marker-based surveys of the Iberian honey bee. Yet, in spite of the numerous studies, the evolutionary processes underlying patterns of Iberian honey bee genetic diversity remain poorly understood. The evolutionary process in the Iberian Peninsula has been dynamic and the genetic consequences are too complex to be addressed piecemeal, using few markers with unknown or poorly known linkage relationships. Accordingly, in 2010 more than 650 honey bee colonies were sampled across latitudinal and longitudinal clines in the Iberian Peninsula. The 650 honey bee samples were genotyped for 1536 SNPs – all equally distributed across the honey bee genome and all with known linkage relationships, based on the latest honey bee genome assembly. Herein we show the preliminary results of this genotyping, focusing on an Iberian honey bee genome inquiry on recent selective sweeps. We provide new insights into the evolutionary processes shaping the Iberian honey bee patterns

Spatial patterns of genetic variation in the Iberian honey bee hybrid zone: a comparison between mitochondrial and nuclear DNA

The Iberian honey bee (Apis mellifera iberiensis) has been intensely surveyed for genetic variation with different markers ranging from morphology, allozymes, mitochondrial DNA (mt DNA), to microsatellites. Some of these markers have revealed non-concordant complex patterns of genetic variation, which led scientists to evoke competing hypotheses for the origin of Iberian honey bees. While complex patterns and underlying historical processes are typical of hybrid zones, the use of more powerful molecular and analytical tools and the fine-scale sampling promised to help dissecting the complexities of the Iberian hybrid zone. In this study, we conducted a genome-wide sampling by genotyping over 384 SNPs (single nucleotide polymorphisms) and sequenced an intergenic fragment of the mt DNA in 711 georeferenced honey bee samples collected across three North-South transects in the Iberian Peninsula. Both mt DNA and SNP datasets were analyzed using spatial tools to represent the structure generated by both types of molecular markers. We found concordant spatial patterns between markers which led to rejection of the standing hypothesis of recent human introductions and selection as the processes shaping Iberian honey bees patterns. This study shows that the fine-scale genomic and spatial analyses can reveal patterns which would otherwise had been undetected.Fundação para a Ciência e Tecnologi

Padrões de variação genética em loci sob selecção na abelha ibérica: comparação da selecção balanceada e direccional

A Península Ibérica tem sido reconhecida como um "hotspot" de diversidade c endemismo para diversas espécies quer animais quer vegetais. Em parte esta grande diversidade encontrada na Península Ibérica deve-se ao flicto de este local ter sido utilizado como refúgio por diferentes espécies durante as glaciaçôes A abelha é um dos muitos casos onde este processo aconteceu. Na verdade, a Península Ibérica é umas das regiões da Europa onde esta espécie apresenta uma maior diversidade c complexidade genética. A abelha ibérica que está distribuída pela Península Ibérica é o fruto de uma hibridação natural entre a linhagem Africana c a linhagem da Europa ocidental. O estudo de zonas híbridas tem sido muito importante para compreender os processos evolutivos que levaram à complexidade genética tão característica dos refúgios O objectivo deste trabalho é fazer uma abordagem inicial para perceber como é que os diferentes tipos de selecção (balanceadora e direccional) influenciam a diversidade genética das abelhas na Península Ibérica e tentar perceber qual o papel da selecção na divergência adaptativa das populações. Para tal foram calculadas algumas cstatisticas sumárias e também toram utilizados diversos sothvares que implementam algoritmos Bayesianos de forma a verificar que estrutura é captada ao utilizar-se as regiões do genoma sob diferentes tipos de selecção (balanceadora ou direccional). No total foram detectados 22 loci sob selecção usando o Bayescan, 9 dos quais apresentavam aparentam estar sob de uma selecção balanceada c 13 sob selecção direccional. Neste trabalho é representado o padrão obtido utilizado software "STRUCTURE

Firm finances, weather derivatives and geography

This paper considers some intellectual, practical and political dimensions of collaboration between human and physical geographers exploring how firms are using relatively new financial products – weather derivatives – to displace any costs of weather-related uncertainty and risk. The paper defines weather derivatives and indicates how they differ from weather insurance products before considering the geo-political, cultural and economic context for their creation. The paper concludes by reflecting on the challenges of research collaboration across the human–physical geography divide and suggests that while such initiatives may be undermined by a range of institutional and intellectual factors, conversations between physical and human geographers remain and are likely to become increasingly pertinent. The creation of a market in weather derivatives raises a host of urgent political and regulatory questions and the confluence of natural and social knowledges, co-existing within and through the geography academy, provides a constructive and creative basis from which to engage with this new market and wider discourses of uneven economic development and climate change

Patrones de diversidad neutral y adaptativa de la abeja Ibérica

La península ibérica es conocida como un importante foco (hotspot) de diversidad y endemismos de numerosas especies de plantas y animales representando por ello una de las regiones prioritarias por la conservación en Europa. Varios factores geomorfológicos y ambientales contribuyen a esta riqueza, concretamente: la localización geográfica en el extremo sudoeste de Europa, el aislamiento en relación al resto de Europa por la barrera geográfica de los Pirineos, la complejidad fisiográfica y la diversidad climática resultante de la heterogeneidad fisiográfica y de las distintas influencias del Atlántico y del Mediterráneo. Una conjugación de estos factores hacen de la península ibérica no solo uno cuna de diferenciación y especiación sino también un importante refugio que albergó durante varios periodos glaciales del Pleistoceno muchas de las especies de plantos y animales que hoy colonizan el Norte y el Centra de Europa {Hewitt, 1999).Fundação para a Ciência e Tecnologi

Africanization of a feral honey bee (Apis mellifera) population in South Texas: Does a decade make a difference?

The arrival to the United States of the Africanized honey bee, a hybrid between European subspecies and the African subspecies Apis mellifera scutellata, is a remarkable model for the study of biological invasions. This immigration has created an opportunity to study the dynamics of secondary contact of honey bee subspecies from African and European lineages in a feral population in South Texas. An 11-year survey of this population (1991-2001) showed that mitochondrial haplotype frequencies changed drastically over time from a resident population of eastern and western European maternal ancestry, to a population dominated by the African haplotype. A subsequent study of the nuclear genome showed that the Africanization process included bidirectional gene flow between European and Africanized honey bees, giving rise to a new panmictic mixture of A.m.scutellata- and European-derived genes. In this study, we examined gene flow patterns in the same population 23 years after the first hybridization event occurred. We found 28 active colonies inhabiting 92 tree cavities surveyed in a 5.14 km2 area, resulting in a colony density of 5.4 colonies/km2. Of these 28 colonies, 25 were of A.m. scutellata maternal ancestry, and three were of western European maternal ancestry. No colonies of eastern European maternal ancestry were detected, although they were present in the earlier samples. Nuclear DNA revealed little change in the introgression of A.m.scutellata-derived genes into the population compared to previous surveys. Our results suggest this feral population remains an admixed swarm with continued low levels of European ancestry and a greater presence of African-derived mitochondrial genetic composition.Peer reviewedZoolog