Geographic origin affects larval competitive ability in European populations of the blow fly, Lucilia sericata

The blow fly, Lucilia sericata (Meigen) (Diptera: Calliphoridae), is found throughout Europe. In northern areas, in addition to breeding in carrion, it can also commonly act as primary facultative ectoparasite of sheep, resulting in animal suffering and production losses. However, in the south of Europe, L. sericata is not usually implicated in myiasis and is found almost entirely in carrion. The causes of this behavioural difference are unclear. To begin to address the possible reasons for this difference, the present study examined the effects of competition on the survival and development of L. sericata populations derived from southern Spain, England, and a hybrid derived from a cross between Spanish females and UK males. Larvae were reared at a range of different initial densities and the mortality, development rate, and size of the resultant adults were measured. Mortality increased significantly with density, but the Spanish population had a significantly higher mortality rate than the UK population at all densities. Similarly, adult size declined with increased larval density, but individuals from the Spanish population were consistently larger than those from the UK population at all densities. The mortality and size of the hybrids was consistently intermediate between the Spanish and UK populations. No consistent effects on development rate were observed. This study demonstrates that insects from northwestern and southern European population have qualitatively different life history traits and competitive abilities and may contribute towards explaining the different behaviour of populations of this species in different part of its distribution range.     

Genetic differentiation of populations of Iberian rock‐lizards Iberolacerta (Iberolacerta) sensuArribas (1999)

The genetic structure and relationships of five populations of the Iberian group of Iberolacerta (sensu 6 ) were analysed by protein electrophoresis. In this study we confirmed the differentiation between the group of populations from Galicia/Cantabrian/S. Estrela versus the group of populations from de Spanish Central System, Gredos and Guadarrama that are included in the two different species by Arribas (Herpetozoa 9(1/2), 31–56, 1996; Russian J. Herpetol. 6, 1–22, 1999), Iberolacerta (I.) monticola and Iberolacerta (I.) cyreni, respectively. However, the differentiation level is not high enough to clearly prove their specific discrimination. On the other hand, we did not confirm the subspecific discrimination of the Gredos –Iberolacerta (I.) cyreni castiliana, and Guadarrama –Iberolacerta (I.) cyreni cyreni populations, proposed by 5 ). These two populations are genetically almost homogeneous. Interestingly, we found an unexpected high genetic similarity between the Galician and the Serra da Estrela populations, presently included into two different subspecies, Iberolacerta (I.) monticola cantabrica and Iberolacerta (I.) monticola monticola, respectively. Their genetic similarity is even higher than that between the populations of Galicia and the Cantabrian Mountains, which are both included in the same subspecies, cantabrica. This result suggests that the populations of Galicia and Serra da Estrela would have maintained contacts, possibly through the north of Portugal, until relatively recent times. Their separation is thus probably post‐glacial. Some evidence also points to the existence of relatively recent contacts between the population of Serra da Estrela and those of the Central System, particularly, with the neighbouring Peña de Francia population. With the cautions imposed by the reduced sample size of our analysis, the significant differentiation of the populations from Galicia and the Cantabrian Mountains allow us to suggest that this last population may not be the result of a recent expansion of the Galician population as 5 ) suggests, but, more likely, the result of a fragmentation process of a more ancient and wider north‐eastern distribution area of this group of rock‐lizards.     

Low genome‐wide homozygosity in 11 Spanish ovine breeds

The population of Spanish sheep has decreased from 24 to 15 million heads in the last 75 years due to multiple social and economic factors. Such a demographic reduction might have caused an increase in homozygosity and inbreeding, thus limiting the viability of local breeds with excellent adaptations to harsh ecosystems. The main goal of our study was to investigate the homozygosity patterns of 11 Spanish ovine breeds and to elucidate the relationship of these Spanish breeds with reference populations from Europe, Africa and the Near East. By using Ovine SNP50 BeadChip data retrieved from previous publications, we have found that the majority of studied Spanish ovine breeds have close genetic relatedness with other European populations; the one exception is the Canaria de Pelo breed, which is similar to North African breeds. Our analysis has also demonstrated that, with few exceptions, the genomes of Spanish sheep harbor fewer than 50 runs of homozygosity (ROH) with a total length of less than 350 Mb. Moreover, the frequencies of very long ROH (>30 Mb) are very low, and the inbreeding coefficients (F_ROH) are generally small (F_ROH < 0.10), ranging from 0.008 (Rasa Aragonesa) to 0.086 (Canaria de Pelo). The low levels of homozygosity observed in the 11 Spanish sheep under analysis might be due to their extensive management and the high number of small to medium farms.     

Genetic admixture despite ecological segregation in a North African sparrow hybrid zone (Aves,Passeriformes, Passer domesticus × Passer hispaniolensis)

Under different environmental conditions, hybridization between the same species might result in different patterns of genetic admixture. Particularly, species pairs with large distribution ranges and long evolutionary history may have experienced several independent hybridization events over time in different zones of overlap. In birds, the diverse hybrid populations of the house sparrow (Passer domesticus) and the Spanish sparrow (Passer hispaniolensis) provide a striking example. Throughout their range of sympatry, these two species do not regularly interbreed; however, a stabilized hybrid form (Passer italiae) exists on the Italian Peninsula and on several Mediterranean islands. The spatial distribution pattern on the Eurasian continent strongly contrasts the situation in North Africa, where house sparrows and Spanish sparrows occur in close vicinity of phenotypically intermediate populations across a broad mosaic hybrid zone. In this study, we investigate patterns of divergence and admixture among the two parental species, stabilized and nonstabilized hybrid populations in Italy and Algeria based on a mitochondrial marker, a sex chromosomal marker, and 12 microsatellite loci. In Algeria, despite strong spatial and temporal separation of urban early‐breeding house sparrows and hybrids and rural late‐breeding Spanish sparrows, we found strong genetic admixture of mitochondrial and nuclear markers across all study populations and phenotypes. That pattern of admixture in the North African hybrid zone is strikingly different from i) the Iberian area of sympatry where we observed only weak asymmetrical introgression of Spanish sparrow nuclear alleles into local house sparrow populations and ii) the very homogenous Italian sparrow population where the mitogenome of one parent (P. domesticus) and the Z‐chromosomal marker of the other parent (P. hispaniolensis) are fixed. The North African sparrow hybrids provide a further example of enhanced hybridization along with recent urbanization and anthropogenic land‐use changes in a mosaic landscape.     

Population genetics after fragmentation: the case of the endangered Spanish imperial eagle (Aquila adalberti)

The highly endangered Spanish imperial eagle, Aquila adalberti, has suffered from both population decline and fragmentation during the last century. Here we describe the current genetic status of the population using an extensive sampling of its current distribution range and both mitochondrial control region sequences and nuclear microsatellite markers. Results were evaluated in comparison to those obtained for the Eastern imperial eagle, Aquila heliaca, its nearest extant relative. Mitochondrial haplotype diversity was lower in the Spanish than in the Eastern species whereas microsatellite allelic richness and expected heterozygosity did not differ. Both allelic richness and expected heterozygosity were lower in the small Parque Nacional de Doñana breeding nucleus compared to the remaining nuclei. A signal for a recent genetic bottleneck was not detected in the current Spanish imperial eagle population. We obtained low but significant pairwise F_ST values that were congruent with a model of isolation by distance. F_ST and exact tests showed differentiation among the peripheral and small Parque Nacional de Doñana population and the remaining breeding subgroups. The centrally located Montes de Toledo population did not differ from the surrounding Centro, Extremadura and Sierra Morena populations whereas the latter were significantly differentiated. On the other hand, a Bayesian approach identified two groups, Parque Nacional de Doñana and the rest of breeding nuclei. Recent migration rates into and from Parque Nacional de Doñana and the rest of breeding nuclei were detected by assignment methods and estimated as 2.4 and 5.7 individuals per generation, respectively, by a Bayesian approach. We discuss how management strategies should aim at the maintenance of current genetic variability levels and the avoidance of inbreeding depression through the connection of the different nuclei.     

Blood biochemical polymorphisms as markers for genetic characteristics of wild Spanish and domestic rabbits

Seventeen blood proteins were studied in a sample of 412 Spanish wild rabbits and in 598 domestic rabbits belonging to various breeds. The wild rabbit populations showed a high level of genetic polymorphism. Six loci were monomorphic, while the remaining ten loci were segregating for at least two alleles. Two of the loci that were polymorphic in the wild rabbits were monomorphic in the domestic ones. Wright's inbreeding coefficient in the total Spanish wild rabbit population was F=5.66, indicating subdivision of the total population. Inbreeding coefficients, estimated by Kidd et al.'s method (Anim. Blood Grps, Biochem. Genet. 11: 21–38), differed significantly from zero, being 15.62%, in wild rabbits and 6–12% in domestic breeds, indicating consanguinity.Genetic distances between wild rabbit populations showed that factors other than geographic distance (e.g., bottlenecks, barriers such as rivers, mountains, etc.) may explain the result that a northern population forms a cluster with two central populations whereas the northeastern populations form a different cluster with another central population. Populations of the first cluster are more closely related to the captive populations than others.There are three population clusters of domestic rabbits, namely (1) New Zealand White and a hybrid combination; (2) Spanish Common, Butterfly, Burgundy, and Californian; and (3) Spanish Giant.     

The poor health of deep-water species in the context of fishing activity and a warming climate: will populations of Molva species rebuild or collapse?

Many deep-water fish populations, being K-selected species, have little resilience to overexploitation and may be at serious risk of depletion as a consequence. Sea warming represents an additional threat. In this study, the condition, or health, of several populations of common ling (Molva molva), blue ling (Molva dypterygia) and Mediterranean or Spanish ling (Molva macrophthalma) inhabiting different areas in the North Atlantic and the Mediterranean was evaluated, to shed light on the challenges these deep-water species are facing in the context of fishing activity and a warming climate. The data on the condition of Molva populations which are analysed here have been complemented with data on abundance and, for the southernmost species (Mediterranean ling), with two other health indicators (parasitism and hepato-somatic index). Despite some exceptions (e.g., common ling in Icelandic waters), this study shows that the condition of many populations of Molva species in the northeastern Atlantic and the Mediterranean Sea has worsened, a trend which, in recent decades, has usually been found to be accompanied by a decline in their abundance. In addition, the poor health status of most populations of common ling, blue ling and Mediterranean ling considered in this analysis points to a lower sustainability of these populations in the future. Overall, the health status and abundance of Molva populations in the northeastern Atlantic and the Mediterranean suggest that only some populations located in the North Atlantic may be able to rebuild, whereas the populations in southern North Atlantic and the Mediterranean, which are probably most at risk from sea warming, are facing serious difficulties in doing so. In the context of fisheries and global warming, this study's results strongly indicate that management bodies need to consider the health status of many of the populations of Molva species, particularly in southern European waters, before implementing their decisions.     

Evidence for the enemy release hypothesis in <Emphasis Type="Italic">Hypericum perforatum</Emphasis>

The enemy release hypothesis (ERH), which has been the theoretical basis for classic biological control, predicts that the success of invaders in the introduced range is due to their release from co-evolved natural enemies (i.e. herbivores, pathogens and predators) left behind in the native range. We tested this prediction by comparing herbivore pressure on native European and introduced North American populations of Hypericum perforatum (St Johns Wort). We found that introduced populations occur at larger densities, are less damaged by insect herbivory and suffer less mortality than populations in the native range. However, overall population size was not significantly different between ranges. Moreover, on average plants were significantly smaller in the introduced range than in the native range. Our survey supports the contention that plants from the introduced range experience less herbivore damage than plants from the native range. While this may lead to denser populations, it does not result in larger plant size in the introduced versus native range as postulated by the ERH.     

Range‐wide population genetic structure of the Caribbean sea fan coral,Gorgonia ventalina

The population structure of benthic marine organisms is of central relevance to the conservation and management of these often threatened species, as well as to the accurate understanding of their ecological and evolutionary dynamics. A growing body of evidence suggests that marine populations can be structured over short distances despite theoretically high dispersal potential. Yet the proposed mechanisms governing this structure vary, and existing empirical population genetic evidence is of insufficient taxonomic and geographic scope to allow for strong general inferences. Here, we describe the range‐wide population genetic structure of an ecologically important Caribbean octocoral, Gorgonia ventalina. Genetic differentiation was positively correlated with geographic distance and negatively correlated with oceanographically modelled dispersal probability throughout the range. Although we observed admixture across hundreds of kilometres, estimated dispersal was low, and populations were differentiated across distances <2 km. These results suggest that populations of G. ventalina may be evolutionarily coupled via gene flow but are largely demographically independent. Observed patterns of differentiation corroborate biogeographic breaks found in other taxa (e.g. an east/west divide near Puerto Rico), and also identify population divides not discussed in previous studies (e.g. the Yucatan Channel). High genotypic diversity and absence of clonemates indicate that sex is the primary reproductive mode for G. ventalina. A comparative analysis of the population structure of G. ventalina and its dinoflagellate symbiont, Symbiodinium, indicates that the dispersal of these symbiotic partners is not coupled, and symbiont transmission occurs horizontally.     

Update of genetic information for the white-clawed crayfish in Spain,with new insights into its population genetics and origin

The white-clawed crayfish is endemic to western and southern Europe and its populations have decreased over recent decades. Spanish populations are generally poorly represented in scientific reports and are usually studied only with a single molecular marker. Here, we use two mitochondrial markers (cytochrome oxidase subunit I and rDNA 16S genes) to examine levels and patterns of genetic structure across the range of the species’ distribution in Spain. Data reveal the existence of two main genetic groups of white-clawed crayfish in Spain with the Ebro basin as a possible contact zone. Processes occurred in historical and recent times, such as genetic drift and translocations, contribute greatly to this genetic structure. Levels of genetic variability and genetic structure of Spanish populations together with demographic inferences suggest that the species established in the Iberian Peninsula, at least since the Late Pleistocene. Knowing the true origin of the Spanish populations is crucial when deciding upon the management policies that should be followed. Given the lack of any clear evidence against its indigenous status, we propose that current protection and conservation measures should be maintained. From a management point of view, we suggest that Spanish population should be considered as a single evolutionary significant unit (ESU) with two management units (MUs) corresponding with the genetic clusters detected in the present study.     

Genetic structure of the white croaker, <Emphasis Type="Italic">Micropogonias furnieri</Emphasis> Desmarest 1823 (Perciformes: Sciaenidae) along Uruguayan coasts: contrasting marine,estuarine, and lacustrine populations

Micropogonias furnieri is widely distributed in the southwestern Atlantic Ocean. In Uruguay, Laguna de Rocha and Río de La Plata estuary have been reported as reproductive and nursery areas. In Laguna de Rocha, individuals reach maturity at smaller total length than their oceanic counterparts. It has been difficult to establish whether Laguna de Rocha represents a biologically distinct population or simply ecophenotypic variation. More generally, the possible presence of several distinct populations of white croakers in Uruguayan waters has been hypothesized, but limited data exist to substantiate them. A recent mitochondrial DNA analysis suggested divergence between the Río de La Plata and the Oceanic front populations. Using seven microsatellites loci, we studied the population structure of M. furnieri in the nursery areas suggested by the literature, as well as in three additional localities to test these hypotheses. The individuals of Laguna de Rocha showed a moderate genetic differentiation with respect to some of the other populations surveyed. Specimens of Montevideo showed the higher genetic distinctiveness. Given the apparent absence of geographical barriers, other factors may be responsible for the observed differentiation. The complex pattern of forces interacting in this system makes it difficult to disentangle the causes of the population structure found. The adaptation to local environmental conditions could be playing an important role in population differentiation, as well as the possible selective pressures imposed by fisheries. The results obtained in this work offer clues about the processes responsible for differentiation of fishes in estuarine and marine environments.     

Genomic diversity and population structure of Mexican and Spanish bovine Lidia breed

The Lidia bovine breed is distinguished for its low genetic exchangeability given its selection on aggressive behavior, its management uniqueness and its subdivided structure. In this study, we present a comprehensive genome‐wide analysis of genetic diversity, population structure and admixture of 468 animals from Mexican and Spanish Lidia breed populations and 64 samples belonging to 10 Spanish native and American‐creole breeds using 37 148 single nucleotide polymorphisms. We found similar average inbreeding values in the Lidia breed, with different distributions within groups; variability of inbreeding values among Spanish lineages was significant and no differences were found among the Mexican sub‐populations. Together, the high F_IS of the lineages and the behavior of the runs of homozygosity are consequences of the lineage's small effective population sizes, contributing to their inbreeding increase. Population admixture analysis discarded any influence on the genetic structure of the Lidia populations from the Spanish native and American‐creole breeds. In addition, both Lidia populations depicted different genetic origins, with the exception of some Mexican individuals whose origins traced back to recent Spanish importations.     

A study of palmar flexion creases in the Mediterranean Populations of Delta de l'Ebre and Murcia (Spain)

This brief report is part of an extensive research which aims to describe different somathoscopic and dermatoglyphic characters of the Spanish population of the Mediterranean. Palmar flexion creases are of a somathoscopic character, independent of dermatoglyphics, they have been scarcely studied in European populations compared to other geographical areas. In this study the results of two Spanish Mediterranean Populations (Delta de l'Ebre and Murcia) have been reported. In the Spanish variation range, Delta de l'Ebre shows the lowest DRBC frequencies, while Murcia presents the highest. Comparisons with various Indian samples also show extreme statistical differences, due to their opposite distribution of the SRBC and TRBC types with respect to Europeans, except for the Punjabi population, which seems to be more similar to the Europeans than to the Indians.     

Mating behaviour of the ‘cosmopolitan’ species Phyllognathopus viguieri (Copepoda: Harpacticoida) and its systematical significance

The mating behaviour was studied and recorded on video with individuals of four cultures of Phyllognathopus viguieri from different populations obtained from the interstitial water of a slow sand filter near the river Ruhr (Germany) (Ruhr population), from a compost heap in Bethesda (Maryland, USA) (Maryland population), from a rain gauge in Windsor Campbell farm (Jamaica) (Jamaica population), and a tree trunk with moss in a forest in the municipality of Rio de Janeiro (Brazil) (Brazil population). The mating behaviour was divided into the well‐known initial phase, copula phase and postcopulatory mate guarding phase. An additional phase prior to the initial phase serves to recognize the female, the recognition phase. The mating behaviour is identical in the males of the Jamaica and Brazil populations of P. viguieri. A postcopulatory mate guarding phase is not found in these two groups. Here, we refute the hypothesis, that a postcopulatory mate guarding phase is found in taxa in which only adult males grasp adult females. The males of the Ruhr and Maryland populations differ from each other in their mating behaviour. Generally, the males of all four populations do not mate with fertilized females which are equally unattractive to the males, i.e., females mate only once in their lifetime to produce offspring. These results corroborate the view that the different populations of P. viguieri do not belong to a single cosmopolitan species.     

Genetic diversity in Swiss goat breeds based on microsatellite analysis

Genetic diversity in eight Swiss goat breeds was estimated using PCR amplification of 20 bovine microsatellites on 20-40 unrelated animals per breed. In addition, the Creole breed from the Caribbean and samples of Ibex and Bezoar goat were included. A total of 352 animals were tested. The bovine microsatellites chosen amplified well in goat. The average heterozygosity within population was higher in domestic goat (0.51-0.58) than in Ibex (0.17) and Bezoar goat (0.19). Twenty-seven per cent of the genetic diversity in the total population could be attributed to differences between the populations. However, with the exclusion of Ibex from the total population, this proportion dropped to 17%. Principal component analysis showed that all Swiss goat breeds are closely related, whereas the Creole breed, Ibex and Bezoar goat are clearly distinct from all eight Swiss breeds.     

Effect of photoperiod and temperature on the life-cycle of different populations of the peacock butterfly Inachis io

The variation in response to photoperiod and temperature of different populations of the peacock butterfly, Inachis io (L.) (Lepidoptera: Nymphalidae), was investigated to test the extent to which species can adjust their response to the environment, and therefore maximise their reproductive potential. The photoperiodic (adult) diapause induction response varies between populations, and appears to be finely tuned to the local conditions. There is however variation within populations and the response can be adjusted in a population by selective breeding. The developmental rate is not significantly different between three latitudinally distinct populations, over the range of temperatures tested, and pupal weights are similar at given temperatures. However, pupal weights increase with decreasing development temperature. The implications of these findings are discussed with reference to modelling life history strategies.

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Résumé Inachis io (L.), observable dans une grande partie de l'Europe, y présente des différences quant au cycle biologique, au voltinisme et à la durée du développement. Trois populations provenant de la zone de transition entre monovoltinisme et bivoltinisme ont été échantillonnées pour examiner les différences de réponses à la photopériode et à la température, et pour évaluer l'étendue des possibilités d'adaptation de cette espèce à l'environnement et ainsi optimaliser son potentiel reproductif. L'induction photopériodique de la diapause est de type jour long pour toutes les souches examinées, mais la photopériode critique 50 (CPh50) varie suivant les populations et paraît étroitement ajustée aux conditions locales. Il y a cependant assez de variabilité à l'intérieur des populations pour que le seuil puisse être rapidement abaissé dans chaque population par des expériences d'élevage sélectif. Par contre, la vitesse de développement ne varie pas significativement entre les populations pour la gamme de température: 15–27°C. Les poids de chrysalides ne diffèrent pas suivant les populations, bien qu'ils augmentent quand la température de dévelppement diminue. On peut penser que des modèles, prédisant que la diminution du nombre de générations pendant une saison sera accompagnée d'une prolongation de la durée de développement et d'une augmentation de la taille, et que ceci est d'origine génétique et non le résultat seul du refroidissement de l'environnement, ne tiendront pas compte de l'absence de variation entre populations dans la relation entre température et développement.

     

Influence de l'hyperparasitisme sur les populations d'un hymenoptère encyrtidae,Epidinocarsis lopezi,parasitoide de la cochenille du manioc Phenacoccus manihoti introduit au Congo

Résumé Une étude au champ de la dynamique des populations de la cochenille du manioc Phenacoccus manihoti Matt.-Ferr. (Hom. Pseudococcidae) et des agents biologiques qui lui sont associés a été entreprise dans 4 parcelles de manioc Manihot esculenta Crantz (Euphorbiacée) situées dans 2 localités différents du Congo. Elle a essentiellement montré que les 7 à 16% de parasitisme développés par le parasitoïde exotique Epidinocarsis lopezi (De Santis) (Hym. Encyrtidae), 4 ans après son introduction, n'affectent pas significativement la dynamique des populations du ravageur. Les taux importants d'hyperparasitisme (67 à 100%) dont le parasitoïde primaire est l'objet limitent la reproduction de ses populations. Toutefois il est difficile de conclure quant à l'impact réel des hyperparasites sur l'efficacité de l'auxiliaire dans la lutte contre la cochenille.

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A field study of cassava mealybug Phenacoccus manihoti Mat.-Ferr. (Hom. Pseudococcidae) population dynamics, together with that of associated biological agents was made on 4 sample plots in cultivated manioc Manihot esculenta Crantz (Euphorbiacée) in two different areas of the Congo. It showed that four years after introduction, the 7 to 16% of parasitism attributable to the exotic parasitoid Epidinocarsis lopezi (De Santis) (Hym. Encyrtidae), did not significantly affect pest population dynamics. High levels of hyperparasitism (67% to 100%) to which the parasitoid is itself subject limits its population levels. It is, however, impossible to determine the real effect of hyperparasites on the efficiency of the auxiliary in the biological control of the mealybug.

     

Range limits,large‐scale biogeographic variation,and localized evolutionary dynamics in a polymorphic damselfly

Studies of heritable colour polymorphisms allow investigators to track the genetic dynamics of natural populations. By comparing polymorphic populations over large geographic areas and across generations, issues about both morph stability and evolutionary dynamics can be addressed, increasing our understanding of the potential mechanisms maintaining genetic polymorphisms. In the present study, we investigated population morph frequencies in a sex‐limited heritable colour polymorphic damselfly (Ischnura elegans, Vander Linden), with three discrete female morphs. We compared the frequencies of these three female morphs in 120 different populations from ten European countries at differing latitudes and longitudes. There were pronounced differences in morph frequencies both across the entire European biogeographic range, as well as at a smaller scale within regions. We also found considerable between‐population variation at the local scale within regions, particularly at the edges of the range of this species. We discuss these findings in the context of recent models of adaptive population divergence along the range of a species. This polymorphism is thus highly dynamic, with stable morph frequencies at the core of the species range but fluctuating morph dynamics at the range limits. We finish with a discussion of how local interactions and climatic factors can be expected to have a strong influence on the biogeographic patterns in this species and other sexually selected polymorphisms. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 775–785.     

North‐African house martins endure greater haemosporidian infection than their European counterparts

Afro‐Palearctic migrant species are exposed to parasites at both breeding and over‐wintering grounds. The house martin Delichon urbicum is one such migratory species facing high instances of blood parasite infection. In an attempt to determine whether breeding European house martins harbour similar blood parasite communities to populations breeding in North Africa, birds were sampled at their breeding grounds in Switzerland and Algeria. Moreover, haemosporidian prevalence and parasite communities were compared to published data sets on Spanish and Dutch breeding populations. This study furthermore wanted to establish whether co‐infection with multiple genera or lineages of parasites had negative e?ects on host body condition. Breeding house martins caught in Algeria showed a higher prevalence of avian haemosporidian parasites than did European populations. Swiss house martins showed a prevalence comparable to that of Spanish and Dutch populations. There were slight differences in the haemosporidian community between European and North‐African populations in terms of composition and abundance of each lineage. Similar to the Dutch house martins, but in contrast to the Spanish population, infection status and number of genera of parasites infecting single hosts did not in?uence Swiss house martin body condition.     

SPECIES-WIDE POPULATION STRUCTURE IN A SOUTHEASTERN U.S. FRESHWATER FISH,HETERANDRIA FORMOSA: GENE FLOW AND BIOGEOGRAPHY

The phylogeography of the freshwater fish fauna of the southeastern United States has almost achieved paradigm status in evolutionary biology (Avise 1992), and the major geographic features responsible for shaping species distributions are well-characterized. Nevertheless, variation among species in distributions of allele or haplotype frequencies suggests that species-specific processes (e.g., migration) may also play a role in establishing those distributions. There has also been relatively little investigation into how population structure may differ among subregions in the Southeast, for example, on the Florida peninsula versus the U.S. mainland to the northwest and/or northeast. The geology of the peninsula is such that both physical and biotic fluctuations may have been (and still be) particularly important in establishing the population structure of freshwater taxa. This possibility leads to two interesting questions in population genetics. (1) Does gene flow in freshwater species of the region better approximate a one- or two-dimensional pattern? (2) Are populations on the peninsula farther from migration-genetic drift equilibrium than their counterparts on the mainland? These questions were addressed by examining the population strucuture of a livebearing fish, Heterandria formosa; several features of the biology of the species make it particularly likely that recent gene flow has been important in its evolution. I surveyed electrophoretic variation in 34 populations distributed throughout the species range. The phylogeographic patterns observed are in general concordance with those found in other species, although with some differences. A two-dimensional hypothesis of gene flow on the Florida peninsula better explains the data than does a one-dimensional one. There is no evidence that populations on the peninsula are farther from migration-drift equilibrium than those to the northwest. Populations in the northeast have lower genetic diversity than those to the south and west and show no isolation by distance; those results are consistent with a recent range expansion into the northeast, although smaller historical effective population sizes could also explain the pattern.