Distribution Of Sibling Species Research Articles

Molecular and morphological studies on Contracaecum rudolphii A and C. rudolphii B in great cormorants (Phalacrocorax carbo sinensis) from Italy and Israel.

The distribution of parasites is shaped by a variety of factors, among which are the migratory movements of their hosts. Israel has a unique position to migratory routes of several bird species leaving Europe to winter in Africa, however, detailed studies on the parasite fauna of birds from this area are scarce. Our study investigates occurrence and distribution of sibling species among Contracaecum rudolphii complex in Phalacrocorax carbo sinensis from Italy and Israel, to acquire further information on the geographical range of these species to gain deeper knowledge on the ecology of these parasites and their bird host. A total of 2383 Contracaecum were collected from the gastric mucosa of 28 great cormorants (18 from Israel and 10 from Italy). A subsample was processed for morphological analyses in light and scanning electron microscopy (SEM), and for molecular analyses through amplification and sequencing of the ITS rDNA and the cox2 mtDNA, and through PCR-RFLP. All the 683 Contracaecum subjected to molecular identification belonged to C. rudolphii s.l., (300 C. rudolphii A and 383 C. rudolphii B). SEM micrographs provided, for the first time, details of taxonomic structures in male specimens from both sibling species, and the first SEM characterization of C. rudolphii B. This work presents the first data on the occurrence of sibling species of C. rudolphii in Israel and provides additional information on the distribution of C. rudolphii A and B in Italy, confirming the high prevalence and intensity of infection observed in Ph. carbo sinensis from other Italian areas.

Potential malaria vector Anopheles minimus (species A) still persisting in North East India

Vector borne infectious diseases affect two third of the world’s human population and cause millions of deaths every year. Among these, malaria remains one of the major killer in the Indian sub-continent and transmitted uninterruptedly by many efficient vectors and their sibling species. In North East India (NE), Anopheles minimus has been recognized as an important vector which transmits majority of malaria cases. This study primarily focuses on to recognize the presence and distribution of sibling species of An. minimus in certain endemic areas of NE India. Anopheles mosquitoes collected were identified using available morphological keys. The genomic DNA was extracted from the mosquitoes and used to perform species specific PCR (ss PCR) for molecular identification of major malaria vector An. minimus sibling species. Morphological identification suggested the presence of An. minimus sl in low density in the study area. The specimen of An. minimus subjected to ss PCR confirmed the prevalence of only one sibling species namely An. minimus ‘A’ in Sialmari and Chandubi areas. Though in low density, but malaria vector An. minimus is still present in certain endemic areas of NE India. The ss PCR assay used presently suggested that An. minimus sibling species A is prevailing in the region. Presently used ss PCR assay was simpler, faster, cheaper and more readily interpretable than the earlier assays. This information could be useful in understanding of current prevalence and distribution of malaria vector An. minimus and its sibling species complex in NE region of India.

Genetic analysis and population structure of the Anopheles gambiae complex from different ecological zones of Burkina Faso

The Anopheles gambiae complex (Diptera: Culicidae) is the most important vector for malaria in Sub-Saharan Africa, besides other vectors such as Anopheles funestus. Malaria vector control should encompass specific identification, genetic diversity and population structure of An. gambiae to design vector control strategies.The aim of this study was to determine the distribution of sibling species of the An. gambiae complex according to climatic regions related to cotton-growing or cotton-free areas by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Then, variation in mitochondrial cytochrome c oxidase 1 (COI) was used to assess the genetic structure within and between populations from our selected ecological zones.At the sibling species level, the following proportions were found across all samples (n = 180): An. coluzzii 65.56%, An. gambiae stricto sensu (s.s). 21.11%, and An. arabiensis 3.33%. Hybrids between An. gambiae s.s. and An. coluzzii (7.78%) and hybrids between An. coluzzii and An. arabiensis (2.22%) were found. The phylogenetic tree and Integer Neighbour-Joining (IntNJ) haplotype network did not reveal any distinct genetic structure pattern related to climatic or agricultural conditions in Burkina Faso. The Fst (Wright's F-statistic) values close to zero showed a free gene flow and no differentiation in An. gambiae complex populations. Furthermore, neutrality indices calculated by Tajima's D, Fu and Li's D⁎, Fu and Li's F⁎, Fu's Fs tests suggested an excess of rare mutations in the populations.Overall, variation in the proportions of An. gambiae s.s., An. coluzzii and An. arabiensis was found according to climatic regions, but COI analysis did not evidence any population structuring of the An. gambiae complex. These scientific contributions can be used as a basis for further in-depth study of the genetic diversity of the An. gambiae complex for epidemiological risk assessment of malaria in Burkina Faso.

The identity of some specimens previously (mis)identified as Rhinoleucophenga obesa (Loew) (Diptera: Drosophilidae) in Brazil, based on morphological and molecular data, with implications on distribution.

Rhinoleucophenga Hendel is an endemic genus of the New World with most species recorded in Brazil. Rhinoleucophenga obesa (Loew) seemed to be the most widespread species, being recorded in the United States of America, Mexico and Brazil. In the Neotropical region, identifications of R. obesa were commonly based on the description of non-type specimens determined by Costa Lima (1935) and Malogolowkin (1946), although their identities were doubtful. However, the recent redescription of R. obesa from the type-series from Texas, USA, confirmed a long period of misidentifications and a new species, R. cantareira Vilela Bächli, was proposed based on Brazilian specimens. Thus, review of morphological and molecular traits of specimens previously identified as R. obesa in Neotropical biomes are necessary to check the identity and distribution of a group of sibling species: R. obesa, R. cantareira, R. gigantea (Thomson), R. pallida Hendel and R. pampeana Poppe et al. In the present paper, specimens previously determined as R. obesa, sampled in different Brazilian localities, were compared by morphological and molecular traits. Plates of female terminalia of R. cantareira and R. gigantea are presented for the first time. The spermathecal capsules (as well as the male epandrium) revealed useful characteristics to differentiate those species; these morphological differences were corroborated by a sequence fragment of COI. The specimens on which were based the descriptions of Rhinoleucophenga obesa sensu Costa Lima (1935) and sensu Malogolowkin (1946) were reviewed and confirmed as R. cantareira. Other Brazilian specimens from different localities, previously misidentified as R. obesa, were determined as R. gigantea or R. cantareira, with new records for both species. Therefore, the present study corresponds to the advance of identity definition and distribution of sibling species of Rhinoleucophenga commonly sampled in Neotropical inventory studies.

Species Composition and Distribution of Sibling Species of the Genus Chironomus Meigen (Diptera: Chironomidae) in the Curonian and Vistula Lagoons, Baltic Sea

The species compositions of the genus Chironomus in the Curonian and Vistula lagoons are very similar, represented by Ch. plumosus and Ch. balatonicus. In the Curonian Lagoon, in addition to these two species, Ch. muratensis and the first-generation interspecific hybrid Ch. muratensis × Ch. plumosus are also found. In this lagoon, Ch. plumosus occurs most frequently (84%); Ch. balatonicus is considered a subdominant species (24%). In the Vistula Lagoon, on the contrary, the high frequency of occurrence is typical of Ch. balatonicus (89%); for Ch. plumosus, it reaches only 11%. The Ch. plumosus population occupies most of the Curonian Lagoon; Ch. balatonicus is present only in its northern part, from the village of Juodkrante to the city of Klaipeda. In the Vistula Lagoon, Ch. balatonicus is distributed over almost its entire area, while Ch. plumosus is found locally, only near the mouth of the Nogat River. The distribution of the sibling species in the lagoons is determined by the salinity gradient.

New data on chromosomal variability, distribution of sibling species, and hybridization of 46-chromosomal forms of Microtus arvalis sensu lato (Rodentia, Arvicolinae) in the Upper Volga basin

New data are presented on the composition, intraspecific structure, and geographic distribution of the sibling species of common voles in the Upper Volga basin and on the occurrence frequency and temporal dynamics of the complex chromosomal rearrangement of autosome pair 5 in Microtus arvalis f. obscurus in populations from Nizhny Novgorod region. A total of 100 M. arvalis s. l. from 18 localities of the region have been identified by methods of chromosomal analysis (routine and AgNOR staining, C- and G-banding). The forms of M. arvalis s. l. distinguished in the sample include M. rossiaemeridionalis (n = 4), M. arvalis f. obscurus (n = 82), M. arvalis form arvalis (n = 11), and F1 hybrids between the last two forms (n = 3). These results confirm the concept of M. arvalis s. l. taxonomic diversity in the Upper Volga basin and contribute to the cadasters of M. rossiaemeridionalis, M. arvalis f. arvalis and M. arvalis f. obscurus. In addition, they allow a more accurate delimitation of the distribution boundaries of 46-chromosomal M. arvalis s. l. forms in the Upper Volga basin and are indicative of hybridization between them in Nizhny Novgorod region (Sokolsky district), where M. arvalis f. arvalis and F1 hybrids have been recorded for the first time.

Composition and distribution of sibling species of Chironomus Meigen, 1803 (Diptera, Chironomidae) in Curonian Lagoon of the Baltic Sea

The species composition of Chironomus in the Curonian Lagoon has been investigated. It was shown that three sibling species of the plumosus group, namely, Ch. plumosus, Ch. balatonicus, and Ch. muratensis, and a first-generation interspecific hybrid Ch. muratensis × Ch. plumosus lived here. The occurrence frequency in the lagoon was 87, 19, 6, and 3% for Ch. plumosus, Ch. balatonicus, Ch. muratensis × Ch. plumosus, and Ch. muratensis, respectively. The species Ch. plumosus was recorded in all the areas (southern, central, and northern), while Ch. balatonicus was found only in the northern area in the village of Juodkrante near the city of Klaipeda. Presumably, the distribution of these sibling species is due to the presence of a salinity gradient in the lagoon.

Coal fly ash effluent affects the distributions of Brachionus calyciflorus sibling species

Fly ash, a coal combustion residue of thermal power plants and a source of multiple pollutants, has been recognized as an environmental hazard all over the world. Although it is known that fly ash effluent affects density, diversity and distribution of rotifers in drainage systems and receiving water bodies, the effect of fly ash effluent on the distributions of highly similar rotifer species remains unknown. In this study, the mtDNA COI genes of 90 individuals in Brachionus calyciflorus complex from Lake Hui (as a fly ash discharge water pond) and other two neighboring lakes (Lake Fengming and Lake Tingtang) were sequenced and analyzed, and the responses in selected life table demographic parameters (life expectancy at hatching, net reproductive rate, intrinsic rate of population increase and proportion of sexual offspring) of different rotifer populations to fly ash effluent were investigated. Overall, 72 mtDNA haplotypes were defined, and were split into two clades by the phylogenetic trees. The divergence of COI gene sequences between the two clades ranged from 11.8% to17.8%, indicating the occurrence of two sibling species (sibling species I and sibling species II). Sibling species I distributed in all the three lakes, showing strong capabilities for dispersal and colonization, which were supported by its higher level of gene flow (2.60–4.04) between the populations from Lake Hui and each of the other two lakes, longer life expectancy at hatching (101.6–148.2h), and higher net reproductive rate (4.4–16.4 offspring/female) and intrinsic rate of population increase (0.60–0.98/d) when cultured in aerated tap water and fly ash effluent. Sibling species II distributed in both Lake Tingtang and Lake Fengming, showing that its dispersal existed between the two lakes. Considering that the distance between Lake Hui and Lake Fengming is shorter than that between Lake Tingtang and Lake Fengming, sibling species II is able to disperse at least from Lake Fengming to Lake Hui. The restricted distribution of sibling species II in Lake Hui might be attributed to its lower intrinsic rate of population increase (0.34–0.39/d) when cultured in aerated tap water and fiy ash effluent, which might be further lowered by the lower algal food level and quality in Lake Hui.

Genetic Structure of Lutzomyia longipalpis Populations in Mato Grosso Do Sul, Brazil, Based on Microsatellite Markers

Background Lutzomyia longipalpis (Diptera: Psychodidae) is the major vector of Leishmania (Leishmania) infantum and thus plays a crucial role in the epidemiology of American visceral leishmaniasis (AVL). This vector is the best studied species of sand fly in the Neotropical region. Many studies claim that this vector is in fact a species complex; however there is still no consensus regarding the number of species that belong into this complex or the geographical distribution of sibling species. The aim of the present study was to analyze the genetic relationships within Lu. longipalpis populations in the state of Mato Grosso do Sul (MS), Brazil.Methodology/Principal FindingsWe collected 30 Lu. longipalpis (15 females and 15 males) from five localities (Campo Grande, Três Lagoas, Aquidauana, Miranda and Bonito) and 30 Lu. Cruzi from Corumbá, totaling 180 sandflies from MS, and 30 Lu. longipalpis from Estrela de Alagoas, state of Alagoas (AL), Northeast Brazil. We show that eight previously described microsatellite loci were sufficient in distinguishing Lu. longipalpis from Lu. Cruzi, which is a closely related species, and in differentiating between Lu. longipalpis collected in MS versus Estrela de Alagoas. Analyses of the genotypes revealed introgression between sympatric Lu. longipalpis and Lu. Cruzi. Conclusions/SignificanceOur findings support the hypothesis of cryptic species within the Lu. longipalpis complex. Furthermore, our data revealed introgression between Lu. longipalpis and Lu. cruzi. This phenomenon should be further investigated to determine the level and incidence of hybridization between these two species. We also demonstrated that microsatellite markers are a powerful tool for differentiating sand fly populations and species. The present study has elucidated the population structure of Lu. longipalpis in MS and, by extension, the Neotropical Lu. longipalpis complex itself.

Identification and distribution of sibling species of Anopheles maculipennis complex (Diptera: Culicidae) in north-eastern Poland

Identification and distribution of sibling species of Anopheles maculipennis complex (Diptera: Culicidae) in north-eastern Poland

Distribution of sibling species of Anopheles culicifacies s.l. and Anopheles fluviatilis s.l. and their vectorial capacity in eight different malaria endemic districts of Orissa, India

The study was undertaken in eight endemic districts of Orissa, India, to find the members of the species complexes of Anopheles culicifacies and Anopheles fluviatilis and their distribution patterns. The study area included six forested districts (Keonjhar, Angul, Dhenkanal, Ganjam, Nayagarh and Khurda) and two non-forested coastal districts (Puri and Jagatsingpur) studied over a period of two years (June 2007-May 2009). An. culicifacies A, B, C and D and An. fluviatilis S and T sibling species were reported. The prevalence of An. culicifacies A ranged from 4.2-8.41%, B from 54.96-76.92%, C from 23.08-33.62% and D from 1.85-5.94% (D was reported for the first time in Orissa, except for occurrences in the Khurda and Nayagarh districts). The anthropophilic indices (AI) were 3.2-4.8%, 0.5-1.7%, 0.7-1.37% and 0.91-1.35% for A, B, C and D, respectively, whereas the sporozoite rates (SR) were 0.49-0.54%, 0%, 0.28-0.37% and 0.41-0.46% for A, B, C and D, respectively. An. fluviatilis showed a similarly varied distribution pattern in which S was predominant (84.3% overall); its AI and SR values ranged from 60.7-90.4% and 1.2-2.32%, respectively. The study observed that the co-existence of potential vector sibling species of An. culicifacies (A, C and D) and An. fluviatilis S (> 50%) was responsible for the high endemicity of malaria in forested districts such as Dhenkanal, Keonjhar, Angul, Ganjam, Nayagarh and Khurda (> 5% slide positivity rate). Thus, the epidemiological scenario for malaria is dependent on the distribution of the vector sibling species and their vectorial capacity.

Molecular phylogeny of the Greek populations of the genus Ligidium (Isopoda, Oniscidea) using three mtDNA gene segments

The phylogeny of Greek populations of the terrestrial isopod genus Ligidium is reconstructed based on three mtDNA gene segments: 12S rRNA, 16S rRNA and COI. Two widely distributed European species, as well as three outgroups belonging to different isopod genera, were also included in the analyses. The samples used represent almost all Ligidium species known to occur in Greece, as well as several populations of unknown specific status plus some new records. Phylogenetic analyses of the combined data set were performed using Bayesian inference and maximum parsimony. The two main sister clades with good support indicate the sympatric differentiation of two lineages in southern continental Greece (Peloponnisos), where Ligidium populations exhibit a mosaic distribution of sibling species. The insular populations of the Aegean Islands show increased genetic divergence and form separate clades. The presence of a third lineage of Asiatic origin is strongly suggested by both the molecular phylogeny and morphology. The only presumably valid diagnostic morphological character exhibits only partial correspondence to well supported clades of the molecular phylogeny. Genetic differentiation between populations is very high, a fact that can be attributed to the strict ecological specialization of these animals that leads to increased levels of isolation even between populations that are in close proximity. As a consequence, Greek Ligidium populations, especially those present on islands, are unique genetic pools and extremely vulnerable to extinction.

Spatiotemporal distribution of insecticide resistance in Anopheles culicifacies and Anopheles subpictus in Sri Lanka

The malaria situation in Sri Lanka worsened during the 1990s with the emergence and spread of resistance to the drugs and insecticides used for control. Chloroquine resistance has increased rapidly over this period, but adverse changes in malaria transmission are more closely associated with insecticide use rather than drug resistance. Insecticide susceptibility tests were routinely carried out in key anopheline vectors across the country for more than a decade. These sentinel data were combined with data collected by other research programmes and used to map the spatial and temporal trends of insecticide resistance in the main vectors, Anopheles culicifacies and A. subpictus, and to examine the relationship between insecticide resistance, changes in national spraying regimens and malaria prevalence. Both species had widespread resistance to malathion, the insecticide of choice in the early 1990s. Both species were initially susceptible to the organophosphate and pyrethroid insecticides used operationally from 1993, but some resistance has now been selected. The levels of malathion and fenitrothion resistance in A. subpictus were higher in some ecological regions than others, which may be related to the distribution of sibling species, agricultural pesticide exposure and/or environmental factors. The study highlights that the emergence and spread of insecticide resistance is a constant threat and that active surveillance systems are vital in identifying key vectors and evidence of resistance.

New method for field studies on the parapatric distribution of sibling species

Spatial segregation (parapatry) often occurs between closely related species. The distributions of the two species are sometimes defined with a small overlapping zone (called a `sympatric area') which generally shifts. Exclusion is necessary to explain the persistence and shift of such a spatial pattern. Field studies are carried out to identify the type of interaction that leads to the required exclusion. This is usually achieved by estimating competition and predation parameters to define the type of interaction strong enough to imply exclusion. But interaction parameters are estimated by quantitative methods which require prolonged observation (5–10 years). These estimations are thus difficult to obtain and are open to criticism because of the spatial and temporal variations in the biotic context. Now the study of these variations requires estimation of several other interaction parameters (for different times and sites); therefore, we are unable to discuss these criticisms from a study of realistic duration. We have, therefore, developed a faster study method using the spatial properties of the sympatric area (width and velocity). We used a between-species competition and a predation model, spatially extended with coupled map lattice formalism (CML), to generate substitution waves corresponding to the `moving sympatric area' and to study their spatial properties (asymptotic width and velocity). The relationships between the asymptotic width and the interaction level had different shapes with competition and predation parameters. We used this difference to define a rapid study method that does not use quantitative estimations of the interaction parameters. This method is more reliable than the usual method with respect to the above criticisms. These findings may have considerable consequences for field studies of parapatry.

The Distribution of Hydroid Sibling Species on Hermit Crabs in Estuaries in the Gulf of Maine

Estuaries in the Gulf of Maine contain disjunct, isolated populations of a number of invertebrate taxa typically distributed only sound of Cape Cod. These estuarine populations may either be remnants of a southern fauna that were stranded by Quaternary changes in water temperature, or they may have been established more recently via larvae that entered the estuaries from the open ocean. We tested these hypotheses by examining the distribution of sibling species of hydroids that are symbiotic on paguriid hermit crabs. These crab-hydroid species pairs differ greatly in their ability to colonize new areas through the water column. The hermit crabs possess a planktonic larva that can disperse great distances, while the hydroids have a crawling planula larva that is extremely limited in its dispersal capabilities. Consequently, estuarine hermit crab populations that lack their native hydroid symbiont are likely to have originated by larval colonization. Hydroid sibling species were identified on the basis of MDH electromorphs. Species identifications were confirmed through a limited number of test matings with colonies of known species identity. In three out of the four estuaries that we examined, shells inhabited by the southern hermit crab,Pagurus longicarpus, were occupied only by the local northern hydroid,Hydractinia polyclina. This pattern is consistent with a more recent establishment of the hermit crab populations through larval dispersal or transport. However, in Casco Bay, shells inhabited byP. longicarpus were occupied by a mixture of the northern hydroid,H. polyclina, and the southern hydroid,H. symbiolongicarpus, that is associated withP. longicarpus throughout the southern part of its range. Thus, theP. longicarpus population in Casco Bay may either be a relict of a former, more broadly distributed population of this crab in the Gulf of Maine, or if recently established, is likely to have originated by the introduction of adult crabs with hydroid-covered shells.