Discovering marine biodiversity in the 21st century

We review the current knowledge of the biodiversity of the ocean as well as the levels of decline and threat for species and habitats. The lack of understanding of the distribution of life in the ocean is identified as a significant barrier to restoring its biodiversity and health. We explore why the science of taxonomy has failed to deliver knowledge of what species are present in the ocean, how they are distributed and how they are responding to global and regional to local anthropogenic pressures. This failure prevents nations from meeting their international commitments to conserve marine biodiversity with the results that investment in taxonomy has declined in many countries. We explore a range of new technologies and approaches for discovery of marine species and their detection and monitoring. These include: imaging methods, molecular approaches, active and passive acoustics, the use of interconnected databases and citizen science. Whilst no one method is suitable for discovering or detecting all groups of organisms many are complementary and have been combined to give a more complete picture of biodiversity in marine ecosystems. We conclude that integrated approaches represent the best way forwards for accelerating species discovery, description and biodiversity assessment. Examples of integrated taxonomic approaches are identified from terrestrial ecosystems. Such integrated taxonomic approaches require the adoption of cybertaxonomy approaches and will be boosted by new autonomous sampling platforms and development of machine-speed exchange of digital information between databases.

Alternaria alternata as endophyte and pathogen

Alternaria alternata is a common species of fungus frequently isolated from plants as both an endophyte and a pathogen. Although the current definition of A. alternata rests on a foundation of morphological, genetic and genomic analyses, doubts persist regarding the scope of A. alternata within the genus due to the varied symbiotic interactions and wide host range observed in these fungi. These doubts may be due in large part to the history of unstable taxonomy in Alternaria, based on limited morphological characters for species delimitation and host specificity associated with toxins encoded by genes carried on conditionally dispensable chromosomes. This review explores the history of Alternaria taxonomy, focusing in particular on the use of nutritional mode and host associations in species delimitation, with the goal of evaluating A. alternata as it currently stands based on taxonomic best practice. Given the recombination detected among isolates of A. alternata, different symbiotic associations in this species should not be considered phylogenetically informative.

Molecular inferences about the genus Hypostomus Lacépède, 1803 (Siluriformes: Loricariidae): a review

This review compiles and discusses the use of genetic markers applied in the study of the fish genus Hypostomus Lacépède, 1803 (Siluriformes: Loricariidae). The database comprises 51 peer-review articles that were published in the last 52 years (1968-2020) and that approach analysis based on different classes of genetic markers. The use of cytogenetic and enzymatic markers was predominantly especially in population studies with the genus Hypostomus, while mitochondrial markers were the majority in phylogenetic studies. Although significant methodological advances have occurred for molecular evaluation, they are still modestly applied to the study of neotropical fish genera, in which Hypostomus is included. New perspectives, especially on integrative approaches, are needed to improve our knowledge of the genetic functionality of fishes.

The genome of the sea anemone Actinia equina (L.): Meiotic toolkit genes and the question of sexual reproduction

The beadlet anemone Actinia equina (L.) (Cnidaria: Anthozoa: Actiniaria: Actiniidae) is one of the most familiar organisms of the North European intertidal zone. Once considered a single, morphologically variable species across northern Europe, it is now recognised as one member of a variable species complex. Previous studies of distribution, aggression, allozymes and mitochondrial DNA suggest that the diversity in form and colour within A. equina may hide still unrecognised species diversity. To empower further study of A. equina population genetics and systematics, we sequenced (PacBio Sequel) the genome of a single A. equina individual to produce a high-quality genome assembly (contig N₅₀ = 492,607 bp, 1485 contigs, number of protein coding genes = 47,671, 97% BUSCO completeness). There is debate as to whether A. equina reproduces solely asexually, since no reliable, consistent evidence of sexual reproduction has been found. To gain further insight, we examined the genome for evidence of a 'meiotic toolkit' - genes believed to be found consistently in sexually reproducing organisms - and demonstrate that the A. equina genome appears not to have this full complement. Additionally, Smudgeplot analysis, coupled with high haplotype diversity, indicates this genome assembly to be of ambiguous ploidy, suggesting that A. equina may not be diploid. The suggested polyploid nature of this species coupled with the deficiency in meiotic toolkit genes, indicates that further field and laboratory studies of this species is warranted to understand how this species reproduces and what role ploidy may play in speciation within this speciose genus.

ALLOZYME VARIATION IN A SNAIL (LITTORINA SAXATILIS)-DECONFOUNDING THE EFFECTS OF MICROHABITAT AND GENE FLOW

It is commonly observed that a restricted gene flow among populations of a species generates genetic differentiation in, for example, allozyme markers. However, recent studies suggest that microhabitat-specific variation may contribute to the total differentiation. To appreciate the relative contributions of geographic variation and habitat-specific variation, we sampled 42 subpopulations of the intertidal snail Littorina saxatilis from three different microhabitats (boulders, low and high rocky intertidal) on five small islands within a distance of 15 km. We used a modified orthogonal version of Nei's gene diversity analysis with a modified analysis of variance (ANOVA) that estimated the significance of habitat and geographic separation and the interaction between them. Between subpopulation differentiation (G_ST ) was usually in the range of 5% to 10% but was exceptionally high in one locus (Aat; 53%). Genetic differentiation attributable to different habitats accounted for 10% to 81% (mean 35%) of the between subpopulation variation and was significant (P < 0.05) in six loci. Differentiation due to geographic separation accounted for 11% to 61% (mean 36%) and was significant (P < 0.05) in seven loci. Furthermore, three loci showed interactions between habitat and island, suggesting varying effects of habitat in different islands. Microhabitat-specific variation, probably through spatially varying fitness, seems particularly likely in Aat and Pgm-2. Moderate levels of habitat associated variation added to the observed differentiation due to gene flow in Pgi, Pnp, and Pgm-1, whereas in the remaining three loci either the habitat effect was confused by strong habitat-island interaction (Ark) or was virtually absent (Pep and Mpi).

DOES COSMOPOLITANISM RESULT FROM OVERCONSERVATIVE SYSTEMATICS? A CASE STUDY USING THE MARINE SPONGE CHONDRILLA NUCULA

The sponge species Chondrilla nucula has a simple morphology and a very wide geographical distribution. To verify whether the latter might be an artifact of the former, samples of this species were collected across 10,000 km of its range, in the Mediterranean, the Caribbean, and the southwestern atlantic. The classical (spicule morphology) and molecular (allozymes) systematic approaches were compared, to try to define the geographic limits between populations and detect possible cryptic species. We found five distinct genetic forms within C. nucula that sometimes showed morphological homogeneity and other times plasticity. The difference in size of spicules could not be related to the clear-cut genetic differences, suggesting that the use of spicule sizes for sponge systematics should be reappraised. The population of one of the genetic forms along 3000 km of the Brazilian coast was highly structured (F_ST = 0.21; N_e m = 0.96). Our results reject the null hypothesis of cosmopolitanism of C. nucula and indicate that the putative worldwide distribution of some marine sponges, and possibly many other benthic invertebrates, may be the result of overly conservative systematics. Cryptic species appear to be particularly prevalent when genera are well defined but species are characterized by only a few morphological characters.

Genetic variability in the natural populations of Lasioderma serricorne (F.) (Coleoptera: Anobiidae), detected by RAPD markers and by esterase isozymes

Lasioderma serricorne (F.) is a small cosmopolitan beetle regarded as a destructive pest of several stored products such as grains, flour, spices, dried fruit and tobacco. Chemical insecticides are one of the measures used against the pest. However, intensive insecticide use has resulted in the appearance of resistant insect populations. Therefore, for the elaboration of more effective control programs, it is necessary to know the biological aspects of L. serricorne. Among these aspects, the genetic variability knowledge is very important and may help in the development of new control methods. The objective of this study was to evaluate the genetic variability of 11 natural populations of L. serricorne collected respectively in three and four towns in the states of Paraná and São Paulo, Brazil, using 20 primers random amplified polymorphic DNA (RAPD) and polymorphisms of esterases. These primers produced 352 polymorphic bands. Electrophoretic analysis of esterases allowed the identification of four polymorphic loci (Est-2, Est-4, Est-5 and Est-6) and 18 alleles. Results show that populations are genetically differentiated and there is a high level of genetic variability within populations. The high degree of genetic differentiation is not directly correlated to geographical distance. Thus, our data indicate that movement of infested commodities may contribute to the dissemination of L. serricorne, facilitating gene flow.

Lock, stock and two different barrels: comparing the genetic composition of morphotypes of the indo-pacific sponge Xestospongia testudinaria

The giant barrel sponge Xestospongiatestudinaria is an ecologically important species that is widely distributed across the Indo-Pacific. Little is known, however, about the precise biogeographic distribution and the amount of morphological and genetic variation in this species. Here we provide the first detailed, fine-scaled (<200 km(2)) study of the morphological and genetic composition of X. testudinaria around Lembeh Island, Indonesia. Two mitochondrial (CO1 and ATP6 genes) and one nuclear (ATP synthase β intron) DNA markers were used to assess genetic variation. We identified four distinct morphotypes of X. testudinaria around Lembeh Island. These morphotypes were genetically differentiated with both mitochondrial and nuclear markers. Our results indicate that giant barrel sponges around Lembeh Island, which were all morphologically identified as X. testudinaria, consist of at least two different lineages that appear to be reproductively isolated. The first lineage is represented by individuals with a digitate surface area, CO1 haplotype C5, and is most abundant around the harbor area of Bitung city. The second lineage is represented by individuals with a predominantly smooth surface area, CO1 haplotype C1 and can be found all around Lembeh Island, though to a lesser extent around the harbor of Bitung city. Our findings of two additional unique genetic lineages suggests the presence of an even broader species complex possibly containing more than two reproductively isolated species. The existence of X. testudinaria as a species complex is a surprising result given the size, abundance and conspicuousness of the sponge.

Diversity and distribution patterns in high southern latitude sponges

Sponges play a key role in Antarctic marine benthic community structure and dynamics and are often a dominant component of many Southern Ocean benthic communities. Understanding the drivers of sponge distribution in Antarctica enables us to understand many of general benthic biodiversity patterns in the region. The sponges of the Antarctic and neighbouring oceanographic regions were assessed for species richness and biogeographic patterns using over 8,800 distribution records. Species-rich regions include the Antarctic Peninsula, South Shetland Islands, South Georgia, Eastern Weddell Sea, Kerguelen Plateau, Falkland Islands and north New Zealand. Sampling intensity varied greatly within the study area, with sampling hotspots found at the Antarctic Peninsula, South Georgia, north New Zealand and Tierra del Fuego, with limited sampling in the Bellingshausen and Amundsen seas in the Southern Ocean. In contrast to previous studies we found that eurybathy and circumpolar distributions are important but not dominant characteristics in Antarctic sponges. Overall Antarctic sponge species endemism is ∼43%, with a higher level for the class Hexactinellida (68%). Endemism levels are lower than previous estimates, but still indicate the importance of the Polar Front in isolating the Southern Ocean fauna. Nineteen distinct sponge distribution patterns were found, ranging from regional endemics to cosmopolitan species. A single, distinct Antarctic demosponge fauna is found to encompass all areas within the Polar Front, and the sub-Antarctic regions of the Kerguelen Plateau and Macquarie Island. Biogeographical analyses indicate stronger faunal links between Antarctica and South America, with little evidence of links between Antarctica and South Africa, Southern Australia or New Zealand. We conclude that the biogeographic and species distribution patterns observed are largely driven by the Antarctic Circumpolar Current and the timing of past continent connectivity.

Sponge ecology in the molecular era

Knowledge of the functioning, health state, and capacity for recovery of marine benthic organisms and assemblages has become essential to adequately manage and preserve marine biodiversity. Molecular tools have allowed an entirely new way to tackle old and new questions in conservation biology and ecology, and sponge science is following this lead. In this review, we discuss the biological and ecological studies of sponges that have used molecular markers during the past 20 years and present an outlook for expected trends in the molecular ecology of sponges in the near future. We go from (1) the interface between inter- and intraspecies studies, to (2) phylogeography and population level analyses, (3) intra-population features such as clonality and chimerism, and (4) environmentally modulated gene expression. A range of molecular markers has been assayed with contrasting success to reveal cryptic species and to assess the genetic diversity and connectivity of sponge populations, as well as their capacity to respond to environmental changes. We discuss the pros and cons of the molecular gene partitions used to date and the prospects of a plentiful supply of new markers for sponge ecological studies in the near future, in light of recently available molecular technologies. We predict that molecular ecology studies of sponges will move from genetics (the use of one or some genes) to genomics (extensive genome or transcriptome sequencing) in the forthcoming years and that sponge ecologists will take advantage of this research trend to answer ecological and biological questions that would have been impossible to address a few years ago.

Sponge systematics facing new challenges

Systematics is nowadays facing new challenges with the introduction of new concepts and new techniques. Compared to most other phyla, phylogenetic relationships among sponges are still largely unresolved. In the past 10 years, the classical taxonomy has been completely overturned and a review of the state of the art appears necessary. The field of taxonomy remains a prominent discipline of sponge research and studies related to sponge systematics were in greater number in the Eighth World Sponge Conference (Girona, Spain, September 2010) than in any previous world sponge conferences. To understand the state of this rapidly growing field, this chapter proposes to review studies, mainly from the past decade, in sponge taxonomy, nomenclature and phylogeny. In a first part, we analyse the reasons of the current success of this field. In a second part, we establish the current sponge systematics theoretical framework, with the use of (1) cladistics, (2) different codes of nomenclature (PhyloCode vs. Linnaean system) and (3) integrative taxonomy. Sponges are infamous for their lack of characters. However, by listing and discussing in a third part all characters available to taxonomists, we show how diverse characters are and that new ones are being used and tested, while old ones should be revisited. We then review the systematics of the four main classes of sponges (Hexactinellida, Calcispongiae, Homoscleromorpha and Demospongiae), each time focusing on current issues and case studies. We present a review of the taxonomic changes since the publication of the Systema Porifera (2002), and point to problems a sponge taxonomist is still faced with nowadays. To conclude, we make a series of proposals for the future of sponge systematics. In the light of recent studies, we establish a series of taxonomic changes that the sponge community may be ready to accept. We also propose a series of sponge new names and definitions following the PhyloCode. The issue of phantom species (potential new species revealed by molecular studies) is raised, and we show how they could be dealt with. Finally, we present a general strategy to help us succeed in building a Porifera tree along with the corresponding revised Porifera classification.

Allozyme differentiation of two populations of the genus Neoplecostomus Eigenmann & Eigenmann, 1888 (Teleostei, Loricariidae) from the upper Paraná River basin, Brazil

Allozyme electrophoresis was used to examine 12 enzymatic systems in two populations of the genus Neoplecostomus from the Paraná River basin. Samples of Neoplecostomus sp. 1 were collected in Paraitinguinha stream of the Tietê River basin, in the municipality of Salesópolis, São Paulo State, and those of Neoplecostomus sp. 2 from São Domingos stream of the Rio Grande River basin, in the municipality of Muzambinho, Minas Gerais State. The genetic variability of the two populations was estimated by Nei’s expected heterozygosity and was considered lower than average for populations of freshwater fish. The proportion of polymorphic loci was low (only 5.26% for the locus Idh). The low frequency of heterozygosity for both populations revealed a high fixation of alleles for each locus. Homozygote excess was observed in both populations. The values of Nei’s genetic identity and the presence of loci with different allele frequencies in both populations may imply that the two populations belong to different species. The genetic variability between populations was compared to other data for loricariids.

Comparative analysis of Trypanosoma rangeli histone H2A gene intergenic region with distinct intraspecific lineage markers

This study shows the characterization of the histone H2A intergenic region sequences (H2A IR) from Trypanosoma rangeli KP1(+) and KP1(-) strains isolated from distinct hosts and geographic regions. Also, a comparative unweighted pair-group method using arithmetic averages (UPMGA) analysis with polymerase chain reaction profiles of the 24Salpha rDNA and the miniexon genes was performed. Detailed H2A IR sequence analysis revealed a discrete size polymorphism among T. rangeli strains and the presence of single-nucleotide polymorphisms and minisatellite repeats, exclusively allowing an interspecific differentiation from T. cruzi strains representing the main parasite lineages. Differently from the H2A IR, UPMGA analysis of the 24Salpha rDNA and the miniexon genes profiles clearly branched T. rangeli strains into KP1(-) and KP1(+) lineages, clustering separately the Brazilian and Colombian KP1(-) strains. The evolutionary implications of these findings are discussed.

Allozyme comparison of two populations of Rineloricaria (Siluriformes, Loricariidae) from the Ivaí River, upper Paraná River basin, Brazil

Two allopatric morphotypes of the genus Rinelocaria were compared through the allozyme electrophoresis technique: one morphotype, R. pentamaculata, from the Keller River in the middle stretch of the Ivaí River basin and the other, R. aff. pentamaculata, from the São João River in the upper portion of the Ivaí River basin. The morphotype from the São João River was collected upstream from the São João waterfall, which is about 80 m deep. Twelve enzymatic systems (AAT, ADH, EST, GCDH, G3PDH, GPI, IDH, LDH, MDH, ME, PGM and SOD) were analyzed, which allowed to score 22 loci. Only lociAat-2, Est-3 and Mdh-C showed polymorphism. The two samples differed in allele frequencies at the three polymorphic loci. The average expected heterozygosity for all loci was 0.0806 ± 0.0447 in the Keller River sample. For the São João River morphotype, this value was 0.0489 ± 0.0350. Nei' s genetic identity and distance between the two populations were respectively 0.9789 and 0.0213. Wright's F_IS , F_IT and F_ST over all loci were estimated as 0.3121, 0.4021 and 0.1309, respectively. We consider that the two morphotypes represent species in statunascendi.

Genetic variability in three species of Gymnotus Linnaeus, 1758 (Gymnotiformes: Gymnotidae) from Caracu stream of the upper Paraná River basin, Brazil

The genetic variability of three Gymnotus species from the Caracu stream, a small tributary of the left margin of Paraná River (Brazilian upper Paraná River floodplain), was estimated with data of 17 putative allozyme loci, which were obtained by using corn starch gel electrophoresis of 10 enzymatic systems: Aspartate aminotransferase (E. C. 2.6.1.1), Alcohol dehydrogenase (E. C. 1.1.1.1), Esterase (E. C. 3.1.1.1), Glucose dehydrogenase (E. C. 1.1.1.118), Glycerol-3-phosphate dehydrogenase (E. C. 1.1.1.8), Isocitrate dehydrogenase (E. C. 1.1.1.42), L-Lactate dehydrogenase (E. C. 1.1.1.27), Malate dehydrogenase (E. C. 1.1.1.37), Superoxide dismutase (E. C. 1.15.1.1) and Sorbitol dehydrogenase (E. C. 1.1.1.14). The genetic diversity was estimated as He = 0.3458 for G. pantanal, He = 0.2481 for G. inaequilabiatus, and He = 0.3152 for G. sylvius. The most divergent species were G. sylvius and G. pantanal (D = 0.117), and the most similar were G. inaequilabiatus and G. pantanal (D = 0.051). The data indicates that the observed genetic variability was very low and the expected variability estimated for these three species is very high, and the genetic differences among them are small. The data suggest that the process of speciation which produced these three species is recent.

Biochemical comparison of two Hypostomus populations (Siluriformes, Loricariidae) from the Atlântico Stream of the upper Paraná River basin, Brazil

Two syntopic morphotypes of the genus Hypostomus - H. nigromaculatus and H. cf. nigromaculatus (Atlântico Stream, Paraná State) - were compared through the allozyme electrophoresis technique. Twelve enzymatic systems (AAT, ADH, EST, GCDH, G3PDH, GPI, IDH, LDH, MDH, ME, PGM and SOD) were analyzed, attributing the score of 20 loci, with a total of 30 alleles. Six loci were diagnostic (Aat-2, Gcdh-1, Gpi-A, Idh-1, Ldh-A and Mdh-A), indicating the presence of interjacent reproductive isolation. The occurrence of few polymorphic loci acknowledge two morphotypes, with heterozygosity values He = 0.0291 for H. nigromaculatus and He = 0.0346 for H. cf. nigromaculatus. F_IS statistics demonstrated fixation of the alleles in the two morphotypes. Genetic identity (I) and distance (D) of Nei (1978) values were I = 0.6515 and D = 0.4285. The data indicate that these two morphotypes from the Atlântico Stream belong to different species.

Genetic structure of natural populations of the sand fly Lutzomyia longipalpis (Diptera: Psychodidae) from the Brazilian northeastern region

In Latin America, Lutzomyia longipalpis is the principal vector of Leishmania chagasi, and is associated with the majority of active foci of visceral leishmaniasis. In spite of the fact that this sand fly is spread practically throughout the entire Neotropical Region, its distribution is not uniform due to geographic and environmental barriers. Geographic isolation coupled with reduced flight abilities may contribute to the appearance of cryptic species of Lutzomyia longipalpis, which may differ in their capacity to transmit L. chagasi. In this work, we describe the genetic structuring patterns based on polymorphism analysis of 24 RAPD-PCR loci of 7 natural populations of Lutzomyia longipalpis obtained from Brazil's northeastern region. The estimated degree of genetic differentiation between populations, based on the population subdivision index theta(ST) (0.136), suggests a moderate degree of genetic structuring as a result of geographical isolation and restricted gene flow. Genetic distances were found to be compatible with those found between members of a single species, suggesting a taxonomic uniformity of Lutzomyia longipalpis in the region studied.

Molecular research and the control of Chagas disease vectors

Chagas disease control initiatives are yielding promising results. Molecular research has helped successful programs by identifying and characterizing introduced vector populations and by defining intervention targets accurately. However, researchers and health officials are facing new challenges throughout Latin America. Native vectors persistently reinfest insecticide-treated households, and sylvatic triatomines maintain disease transmission in humid forest regions (including Amazonia) without colonizing human dwellings. In these scenarios, fine-scale vector studies are essential to define epidemiological risk patterns and clarify the involvement of little-known triatomine taxa in disease transmission. These eco-epidemiological investigations, as well as the planning and monitoring of control interventions, rely by necessity on accurate taxonomic judgments. The problems of cryptic speciation and phenotypic plasticity illustrate this need - and how molecular systematics can provide the fitting answers. Molecular data analyses also illuminate basic aspects of vector evolution and adaptive trends. Here we review the applications of molecular markers (concentrating on allozymes and DNA sequencing) to the study of triatomines. We analyze the suitability, strengths and weaknesses of the various techniques for taxonomic, systematic and evolutionary investigations at different levels (populations, species, and higher taxonomic categories).

Allozyme relationships in hypostomines (Teleostei: Loricariidae) from the Itaipu Reservoir, Upper Rio Paran� basin, Brazil

In an allozyme electrophoresis survey of 15 hypostomine species from the Itaipu Hydroelectric Reservoir, 25 loci from 14 enzyme systems were scored. Allozyme data allowed recording diagnostic genetic markers for all species analyzed and for some species groups within Hypostomus, a taxon which is taxonomically still unresolved in the Upper Rio Paraná basin. The mean expected heterozygosity of the species was considerably variable and hypotheses to tentatively explain this variation are discussed. A cladogram based upon the allelic frequencies of the species analyzed was produced by the continuous maximum likelihood method: Rhinelepis aspera and M. parananus were separated from the species of Hypostominae by a long branch length. Pterygoplichthys anisitsi was the sister of all the representatives of the genus Hypostomus. Within Hypostomus, two main clades were produced: in the first, H. cochliodon was the sister of the species comprising the H. plecostomus group, and in the second, the tree showed the following relationships: (H. albopunctatus (H. regani + Hypostomus sp. 3) + (H. margaritifer (H. microstomus (Hypostomus sp. 1 (H. ternetzi + Hypostomus sp. 2)). Hypostomus ternetzi and Hypostomus sp. 2 are referred to here as representatives of the H. ternetzi group.

Genetic structure of sylvatic, peridomestic and domestic populations of Triatoma dimidiata (Hemiptera: Reduviidae) from an endemic zone of Boyaca, Colombia

Randomly amplified polymorphic DNA (RAPD) technique was used to study the genetic structure of sylvatic, peridomestic and domestic populations of Triatoma dimidiata. The genetic flow among them was calculated to establish the epidemiological risk of non-domiciliated populations in the transmission of Chagas disease in an endemic area of Boyaca, Colombia. A total of 83 adult specimens were studied: 26 sylvatic, 27 peridomestic and 30 domestic insects. Wright's Fst was 0.071 and the effective migration rate (Nm) 3.3, suggestive of low genetic differentiation and a movement of at least three insects per generation. The calculated percentage of polymorphic loci was 99%, confirming a large average heterozygosity due to a permanent contact between insects of the three populations. These results imply that non-domiciliated populations of T. dimidiata represent an epidemiological risk in the transmission of Chagas disease owing to the fact that they can colonize human dwellings. Close surveillance of non-strictly domiciliated species of triatomines such as T. dimidiata should entail not only the domicile but also the peridomicile and should include control programs of animal reservoirs. Houses enhancement, educational programs, surveillance of reinfestation and of individuals at risk of infection should be priorities in the control policies in endemic regions such as Boavita, Boyaca.

Altitudinal variation in morphometric and molecular characteristics of Phlebotomus papatasi populations

Four populations of the phlebotomine sandfly Phlebotomus (Phlebotomus) papatasi (Scopoli) (Diptera: Psychodidae), in different ecoregions at altitudes between 368 and 1117 m in the Sanliurfa Province of Turkey, were compared using morphometric and isoenzyme analyses. A similarity phenogram obtained from allozyme data showed that heterozygosity was extremely low, particularly for the alleles which were found to be completely fixed in populations at Hamdun (HMD) and Alitas (ALT). Populations at Akcakale (AKL) and ALT branched as a separate group from populations at Hayatiharrani (HHR) and HMD. The ALT population at the highest altitude (1117 m), and the HHR population (488 m) were clustered distinctly when linear measurements of 46 morphological characteristics were examined. A UPGMA (unweighted pair-group method using arithmetic averages) phenogram also showed that ALT and HHR clustered separately, whereas AKL and HMD formed another group.

COMPARATIVE POPULATION GENETIC STRUCTURES AND LOCAL ADAPTATION OF TWO MUTUALISTS

Similar patterns of dispersal and gene flow between closely associated organisms may promote local adaptation and coevolutionary processes. We compare the genetic structures of the two species of a plant genus (Roridula gorgonias and R. dentata) and their respective obligately associated hemipteran mutualists (Pameridea roridulae and P. marlothi) using allozymes. In addition, we determine whether genetic structure is related to differences in host choice by Pameridea. Allozyme variation was found to be very structured among plant populations but less so among hemipteran populations. Strong genetic structuring among hemipteran populations was only evident when large distances isolated the plant populations on which they live. Although genetic distances among plant populations were correlated with genetic distances among hemipteran populations, genetic distances of both plants and hemipterans were better correlated with geographic distance. Because Roridula and Pameridea have different scales of gene flow, adaptation at the local population level is unlikely. However, the restricted gene flow of both plants and hemipterans could enable adaptation to occur at a regional level. In choice experiments, the hemipteran (Pameridea) has a strong preference for its carnivorous host plant (Roridula) above unrelated host plants. Pameridea also prefers its host species to its closely related sister species. Specialization at the specific level is likely to reinforce cospeciation processes in this mutualism. However, Pameridea does not exhibit intraspecific preferences toward plants from their natal populations above plants from isolated, non-natal populations.

Isoenzimatic analysis of four Anopheles (Kerteszia) cruzii (Diptera: Culicidae) populations of Brazil

Anopheles cruzii is a small sylvatic mosquito and primary human Plasmodium vector in Southern Brazil. The distribution of this bromeliad-breeding mosquito follows the Atlantic forest coastal distribution, where bromeliads are abundant. Morphological, genetic, and molecular polymorphisms among different populations have been reported and it has recently been suggested that An. cruzii is a complex of cryptic species. The aim of this work is to analyze the gene flow between different populations of An. cruzii collected in four localities within the geographic distribution range of the species, and to examine if An. cruzii is a complex of cryptic species. The genetic distances show that populations of the states of Santa Catarina, Sao Paulo, and Rio de Janeiro are genetically closer (0.032 to 0.083) than populations of Bahia (0.364 to 0.853) based on profiles from 10 distinct isoenzyme loci. The Fst was lower (0.077) when the Bahia population was excluded than when it was included (0.300) in the analyses. The inferred number of migrants per generation was 2.99 individuals among populations from the states of Santa Catarina, Sao Paulo, and Rio de Janeiro and 0.58 migrants per generation among all populations. Results suggest that An. cruzii is a complex of species and that the specimens of state of Bahia can be considered as belonging to a species that is distinct from other three closely-related populations studied.

Isoenzymatic analysis of four Anopheles (Kerteszia) bellator Dyar & Knab (Diptera: Culicidae) populations

Anopheles bellator is a small silvatic bromelia-breeding mosquito and is a primary human malaria vector species in Southern Brazil. The bromelia-breeding habitat of the species should accompany the Atlantic forest coastal distribution, where bromeliads are abundant. Nonetheless, records on An. bellator collections show a gap in the species geographical distribution. An. bellator has been recorded in Southern Brazil and in the Brazilian states of Bahia and Paraíba. It appears again in the island of Trinidad, in Trinidad and Tobago. The aim of this work was to measure gene flow between different populations of An. bellator collected in the northern and southern extremes of the geographic distribution of this species. Mosquitoes were captured in forest borders in Santa Catarina, São Paulo, and Bahia states in Brazil and in the island of Trinidad in Republic of Trinidad and Tobago. Genetic distances varied between 0.076 and 0.680, based on enzymatic profiles from 11 distinct isoenzymes. Results indicate the existence of low-level gene flow between Brazilian populations of An. bellator, and a gene flow was even lower between the Brazilian and the Trinidad populations. This finding lead us to hypothesize that An. bellator did not spread along the coast, but reached northeastern areas through inland routes.

Differentiation and gene flow among island and mainland populations of the true armyworm,Pseudaletia unipuncta(Haworth) (Lepidoptera: Noctuidae)

The genetic structure of populations of the true armyworm, Pseudaletia unipuncta (Haworth) (Lepidoptera: Noctuidae), in the Azores archipelago was studied using polyacrylamide-gel electrophoresis. Four enzyme systems (aldehyde oxidase, esterase, phosphoglucomutase, and phosphoglucose isomerase) were examined in six populations from islands in the Azores (Santa Maria, São Miguel, Terceira, Pico, Faial, Flores) and compared with those from populations from mainland Portugal and Canada. The North American and European populations are not clearly separated from the Azorean ones. Similarly, studies of different enzyme systems (aldehyde oxidase, esterase, malic enzyme, sorbitol dehydrogenase, manose-6-phosphate isomerase, and phosphoglucomutase) over 2 years (1997 and 1998) at different times of the year (spring, summer, and autumn) and at three different altitudes (0, 250, and 500 m above sea level) on three different islands (Santa Maria, São Miguel, and Faial) uncovered no distinct differences. These results, obtained from classically used loci, suggest that there is still some gene flow between sites or that island populations have not been isolated for sufficient time to have diverged from founder populations.