Phylogenetic relationships of Deschampsia antarctica (Poaceae): Insights from nuclear ribosomal ITS

Deschampsia antarctica E. Desv. is the only monocot in the Antarctic floristic zone. We evaluated the phylogenetic relationships of Deschampsia antarctica to other grasses using parsimony as the optimality criterion. Five different sets of gap, transversion and transitions costs were explored to analyze the effect of parameter choice on the phylogenetic results. Both internal transcribed spacers (ITS1 and ITS2) and the 5.8S subunit of nuclear ribosomal DNA were included in the analysis. A total of 43 species were analyzed including seven species of Deschampsia. Deschampsia antarctica forms a well supported group with five species of Deschampsia. Deschampsia does not appear monophyletic as D. flexuosa (L.) Trin. is not included in this clade. The clade to which D. antarctica belongs is sister to some Aveneae in all analyses. This study is the first contribution that evaluates the phylogenetic position of D. antarctica in relation to other species of Deschampsia.     

High diversity of pipistrelloid bats (Vespertilionidae: Hypsugo,Neoromicia, and Pipistrellus) in a West African rainforest with the description of a new species

The pipistrelloid bats (genera Hypsugo, Neoromicia, and Pipistrellus) of Africa have been poorly studied, partly as a result of problems associated with species identification. This paper examines the diversity of pipistrelloid bats from Mount Nimba, a biodiversity hotspot in the Upper Guinean rainforest zone. Traditional morphometrics, the structure of the baculum, and sequences of the cytochrome oxidase subunit I (COI) gene were used to identify taxa. Species richness was exceptionally high and included at least ten taxa identifiable on molecular grounds. Of these, existing names could be assigned to six taxa. A seventh taxon was described as a species new to science, Neoromicia roseveari sp. nov. , and was distinguished on molecular grounds, craniodental morphology, and baculum structure. The remaining taxa may refer to as‐yet undescribed species but we lacked sufficient material to formally describe them here. The high species richness of pipistrelloid bats on Mount Nimba may be associated with the transition zone from lowland rainforest to moist savannah. © 2013 The Linnean Society of London     

Phylogenetic Position of the Subgenus Lordiphosa of the Genus Drosophila (Diptera: Drosophilidae) Inferred from Alcohol Dehydrogenase (Adh) Gene Sequences

We analyzed the phylogenetic relationship between the species of Lordiphosa and other Drosophilidae using alcohol dehydrogenase (Adh) gene sequences. The phylogenetic trees consistently show that the four species Drosophila kurokawai, D. collinella, D. stackelbergi, and D. clarofinis, which include three species groups of Lordiphosa, form a monophyletic clade. This clade is placed as a sister group to the willistoni and saltans groups of Sophophora. On the other hand, three species of Lordiphosa, D. tenuicauda, D. pseudotenuicauda, and D. acutissima, all of which belong to the tenuicauda group, are not shown to be related to the major Lordiphosa lineage. In the phylogenetic trees, these species are included into the clade comprised of Drosophila and Hirtodrosophila, although it remains uncertain whether the tenuicauda group is a monophyletic group or not. These results indicate that Lordiphosa is polyphyletic and that most of the members of the subgenus have a close relationship to the neotropical groups of Sophophora. The above conclusion is compatible with the hypothesis of Okada (Mushi [1963] 37:79–100) and Lastovka and Máca (Acta Ent Bohemoslov [1978] 75:404–420) that Lordiphosa is most closely related to Sophophora; in contrast, our results contradict the hypothesis of Grimaldi (Bull Am Mus Nat Hist [1990] 197:1–139) that Lordiphosa is a sister group to the genus Scaptomyza. Received: 12 May 1999 / Accepted: 14 April 2000     

Adult feeding habits of three Perloidea species (Plecoptera: Perlidae and Chloroperlidae)

The gut content composition of three species of the superfamily Perloidea, Marthamea selysii (Pictet, 1842), Dinocras cephalotes (Curtis, 1827), and Siphonoperla torrentium (Pictet, 1842), from northwestern Spain is analyzed and described. The quantity of food found in all adults of M. selysii and D. cephalotes was very low. Spores of fungi and pollen of angiosperms were the most abundant components in the diet of M. selysii. Pollen of angiosperms, followed by fungal spores, detritus, and animal matter were the most abundant components in the diet of both sexes of D. cephalotes. The adult diet of both sexes of S. torrentium consists mainly of pollen and agrees with data of the previous studies on this same species in other areas. Our results also show that the consumption of animal matter could be a way to get a nutritional complement and is more common than previously considered in adult stoneflies. The obtained data support the hypothesis that adult feeding is less important for large stoneflies (as M. selysii and D. cephalotes) than for other smaller Perloidea (as S. torrentium), but feeding habits in these large Plecoptera could not be as negligible as previously supposed.     

Cryptic speciation among intestinal parasites (Trematoda: Digenea) infecting sympatric host fishes (Sparidae)

In the north‐western (NW) Mediterranean, the teleosts Diplodus sargus, D. vulgaris and D. annularis coexist in infralittoral habitats. These fishes are infected by two species of the Digenea (Platyhelminthes, Trematoda): Macvicaria crassigula (Opecoelidae) and Monorchis parvus (Monorchiidae) for which we obtained Internal Transcribed Spacer rDNA sequences. Each parasite species represents a complex of two cryptic species, one restricted to D. annularis, and the other shared by D. sargus and D. vulgaris. Cytochrome b mtDNA sequences were used to infer host phylogenetic relationships which showed that the distribution of parasites in Diplodus hosts is not a consequence of coevolutionary interactions. We used diet analyses available for the fish hosts to assess the degree of overlap in the use of food among the three species. The feeding overlap was significant only between D. sargus and D. vulgaris, but not for the other fish pairs. The possible mechanisms involved in the speciation of the digenean fauna of Diplodus fishes are discussed.     

Isolation and characterization of nine polymorphic microsatellite markers in the two‐banded sea bream (Diplodus vulgaris) and cross‐species amplification in the white sea bream (Diplodus sargus) and the saddled bream (Oblada melanura)

We have developed nine new microsatellite markers for the two‐banded sea bream (Diplodus vulgaris) from an enriched genome library protocol. All these loci are polymorphic, with mean allelic diversity of 13 (range 5 –21), and expected and observed heterozygosities from 0.641 to 0.932 and 0.428 to 0.914, respectively. Cross‐species tests in two close‐related species of the genus Diplodus (D. sargus and O. melanura) revealed successful amplifications at 8 out of 9 loci, with mean allele number of 4.75 (range 2–8) and 5.50 (range 3 –10), respectively. These results are consistent with the close phylogenetic relationships between the three species, indicating this set of primers might prove useful for studying the levels of genetic diversity and population differentiation in these three species and in other phylogenetically close species of the genus Diplodus and Sparus.     

The distribution and abundance of species of Danthonia DC on the New England Tablelands (Australia)

The distribution and percent frequency of the 13 species and one variety of Danthonia recorded on the New England Tablelands were examined in a survey of 110 predominantly pastoral sites. The relationships between site factors and the presence and percent frequency of the different Danthonia species were subjected to canonical correlation analysis. Individual species were found to have particular sets of environmental factors associated with their distribution and percent frequency; a fact not well recognized in the past. The most common factor associated with the abundance of Danthonia was either a long time since the last cultivation or no cultivation at all. Other factors such as altitude, drainage, soil parent material, soil texture and total soil phosphorus status were also of some importance. The six species most commonly recorded throughout the New England Tablelands were D. racemosa RBr, D. pilosa RBr, D. laevis J. Vickery, D. linkii Kunth., D. richardsonii Cashmore and D. tenuior (Steud.) Conert. Of these the first three are ecologically wide species. The first two can coexist with other naturalized species under grazing while D. laevis tends to disappear with disturbance. D. linkii and D. richardsonii require fairly narrow habitat conditions but these conditions and consequently these species are common. Both species respond positively to disturbance. Danthonia linkii increases with cultivation and D. richardsonii colonizes eroded soil surfaces. Danthonia tenuior has more restricted requirements and is not so frequent The other seven species and one variety did not occur often enough for detailed study and the occurrence of two of these species, D. carphoides and D. caespitosa must be considered as rare.     

Comparative copulation anatomy of the Drosophila melanogaster species complex (Diptera: Drosophilidae)

The Drosophila melanogaster species complex consists of four species: D. melanogaster, D. simulans, D. sechellia and D. mauritiana. To identify these closely related species, researchers often examine the male genitalia, especially species‐specific shapes of the posterior process, as the most reliable and easily observable character. However, compared to genetic aspects, the evolutionary significance of the posterior process and other genital parts remains largely unexplained. By comparing genital coupling among these species, we revealed that the posterior processes, which are hidden under the female abdominal tergite VII when genital coupling is established, mesh with different parts of the intersegmental membrane between the tergite VIII and the oviscapts and that this membrane region broadens in a species‐specific manner. Furthermore, in D. simulans and D. sechellia, this membrane region is likely to incur wounds from the sharply pointed tip of the posterior process. On the basis of the use and functions of these and other genital parts, we discuss possible evolutionary forces underlying the diversification of genitalia in this group.     

Genetic divergence in Northamerican freshwater planarians of the Dugesia dorotocephala group (Turbellaria, Tricladida, Paludicola)

The genetic differentiation between the members of the Dugesia (Girardia) dorotocephala group was analyzed by means of multilocus electrophoresis, and comared to that of another planarian secies, D. tahitiensis, also belonging to the subgenus Girardia. The species examined were: D. dorotocephala s.s (2n = 16), D. arizonensis (2n = 8), D. jenkinsae (2n = 8), and the above mentioned D. tahitiensis (2n = 16). The former three species inhabit North America, and show different proportion of fissiparous and sexual individuals; the latter species inhabits Polynesia and is fully asexual. A total of 11 enzyme loci were genetically analyzed: Mdh-1, Mdh-2, Zdh-1, Idh-2, G3pdh, Got-1, Ck, Pgm-2, Ada, Mpi, and Gpi. Low values of observed mean heterozygosity per locus (Ho) were found in the populations studied, ranging from 0 to 0.18 (average 0.08. In asexual populations (except that of D. tahitiensis) fixed heterozygosity was observered in all the individuals for 1 or 2 loci. The genetic divergence between the species examined is very high, with many loci showing discriminating alleles in different taxa (Nei's genetic distance varies from 0.871 to 1.759). The populations of D. dorotocehala s.s., on the contrary, appear to be genetically quite homogenous average D= 0.019), and the genetic distance values are apparently unrelated to their geographic location and to their way of reproduction. The genetic distance between D. tahitiensis, a species not included in the D. dorotocephala group and D. dorotocephala s.s. is 1.314 and hence similar to the D value between two members of;he dorotocephala group: D. dorotocephala and D. jenkinsae (D = 1.303). The genetic relationships among the populations studied were established by UPGMA cluster analysis and multidimensional scaling. The descendence of the North American species with 2n = 8 from a dorotocephala-like ancestor with 2n = 16 is considered. It is suggested that the latter, as well as a tahitiensis-like line, also having 2n = 16, have originated from a common ancestor by geographic isolation.     

Study of Allelic Polymorphism of (GATA) n -Containing Loci in Parthenogenetic Lizards Darevskia unisexualis (Lacertidae)

The genesis of mini- and microsatellite loci, which is under extensive study in humans and some other bisexual species, has been virtually overlooked in species with clonal mode of reproduction. Earlier, using multilocus DNA fingerprinting, we have examined variability of some mini- and microsatellite DNA markers in parthenogenetic lizards from the genus Darevskia. In particular, mutant (GATA)n-restriction DNA fragments were found in Darevskia unisexualis. In the present study, we examined intraspecific polymorphism of three cloned loci of D. unisexualis—Du323, Du215, and Du281—containing (GATA)₇GAT(GATA)₂, GAT(GATA)₉, and (GATA)₁₀TA(GATA) microsatellite clusters, respectively. Different levels of intrapopulation and interpopulation variability of these loci were found. Locus Du281 showed the highest polymorphism—(six allelic variants in the sample of 68 DNA specimens). Three alleles were found for locus Du215. The Du323 locus was electrophoretically invariant. The primers chosen for loci Du323, Du215, and Du281 were also used for PCR analysis of homologous loci in two presumptive parental bisexual species, D. valentini and D. nairensis. The PCR products of the corresponding loci of the parental species had approximately the same size (200 bp) as their counterparts in D. unisexualis, but the polymorphism levels of the paternal, maternal, and hybrid species were shown to be somewhat different. These data on the structure of the D. unisexualis loci provide a possibility to study genetic diversity in the parthenogenetic species D. unisexualis and other related unisexual and bisexual species of this genus, which can provide new information on the origin of parthenogenetic species and on the phylogenetic relationships in the genus Darevskia. These data can also be used for resolving problems of marking the lizard genome, which is still poorly studied.     

Ultrastructural features of spermatozoa and their phylogenetic application in Zaprionus (Diptera,Drosophilidae)

The genus Zaprionus consists of approximately 60 species of drosophilids that are native to the Afrotropical region. The phylogenetic position of Zaprionus within the Drosophilidae family is still unresolved. In the present study, ultrastructural features of spermatozoa of 6 species of Zaprionus as well as the species Drosophila willistoni and Scaptodrosophila latifasciaeformis were analyzed. The ultrastructure revealed that the species have the same flagellar ultrastructure. Two mitochondrial derivatives, one larger than the other, close to the axoneme were present, primarily in D. willistoni (subgenus Sophophora). Except for Z. davidi and Z. tuberculatus, the analyzed species had paracrystalline material in both mitochondrial derivatives. Moreover, the testes showed 64 spermatozoa per bundle in all of the species. In the cluster analysis, 6 Zaprionus species were grouped closely, but there were some incongruent positions in the cladogram. The results indicated that sperm ultrastructure is an important tool for elucidating the phylogeny and taxonomy of insects.     

Laboratory culture and taxonomy of two species ofDerbesia (Class Chlorophyceae) in Japan

Two species ofDerbesia (Class Chlorophyceae),D. marina andD. tenuissima, have been studied for the purpose of obtaining a better understanding of their morphological details and life histories, using preserved and living specimens as well as laboratory cultures. The life histories of both species were completed in the laboratory, starting from both zoospores and zygotes. Specimens were collected at Asamushi, Aomori-ken, and Shimoda, Shizuoka-ken. Their life history types are fundamentally identical, zoospores giving rise upon germination toa Halicystis-phase, while zygotes grow into aDerbesia-phase. The thallus of theHalicystis-phase which alternates withD. marina is the same as that ofH. ovalis which grows in the northern regions of Japan. On the other hand, the thallus of theHalicystis-phase alternating withD. tenuissima is the same as that ofH. parvula known to occur in the temperate to subtropical regions of Japan. These results coincide with those obtained withD. marina andD. tenuissima in Europe, where the type localities of both species are located. Specimens assignable to these two species were collected at several localities in Japan and, as a result of detailed examination of the morphology, they are believed to be identical with eitherD. marina orD. tenuissima.     

The mitogenome of freshwater loach Homatula laxiclathra (Teleostei: Nemacheilidae) with phylogenetic analysis of Nemacheilidae

The complete mitogenome can provide valuable genetic information to reconstruct relationships between species. In this study, we sequenced a stone loach, Homatula laxiclathra (Teleostei: Nemacheilidae), which is found in the northern region of the Qinling Mountains in China. The size of the H. laxiclathra mitogenome is 16,570 bp, which contains 37 typical mitochondrial genes including 13 protein‐coding genes, 22 transfer RNAs, two ribosomal RNAs, and a control region (D‐loop) with a total AT content of 55.8%. This is similar to other Nemacheilidae sequences published in GenBank. Furthermore, a mito‐phylogenomic analysis of 46 Nemacheilidae species places H. laxiclathra in a robust monophyletic Homatula cluster with other Homatula species. Our results contribute toward a better understanding of a true phylogeny of these species based on large‐scale taxonomic samplings as well as to help grasp the evolution of fish mitogenomes.     

Polystomatidae (Monogenea) of Southern African Anura: Eupolystoma vanasi n. sp. parasitic in Schismaderma carens (Smith)

Eupolystoma vanasi is described as a new species of the Polystomatidae parasitic in the urinary bladder of Schismaderma carens in Northern Province and KwaZulu-Natal Province, South Africa. This is the third Eupolystoma species described from Africa and the first polystomatid from Schismaderma, an anuran genus that is primitive with respect to the other African bufonids in which Eupolystoma has been recorded. The species is distinguished by body size (this is the largest Eupolystoma known; mean length of adults 6 mm), by genital spine number (4 in comparison with 6-9 in other species), marginal hooklet length (greater than in other African species), and by the small size of the ovary and testis. In a sample of 27 toads, 37% were infected with up to 130 parasites per host (mean intensity 37). Worm burdens of this magnitude are exceptional amongst polystomatids in general but are characteristic of Eupolystoma, where there may be repeated re-infection of adult hosts and, uniquely, a direct, internal cycle of auto-infection.     

Relationships within the Melanogaster subgroup species of the genus Drosophila (Sophophora)

Five members of the melanogaster species subgroup of the subgenus Sophophora have been studied cytologically, their mitotic chromosomes analysed after Giemsa, C-banding and quinacrine staining. In all five species (D. yakuba, D. teissieri, D. erecta, D. orena and D. mauritiana) n=4 and all of the species except D. orena have a typical melanogaster like mitotic karyotype though there are clear differences between species in the distribution of both C⁺ and Q⁺ material. D. orena has large metacentric X and Y chromosomes due to the accumulation of intensively fluorescing material on these elements with respect to their homologues in melanogaster. This extra heterochromatin of D. orena correlates with a very high proportion of satellite DNA in its nuclear genome (S. Barnes, unpublished). The polytene chromosomes of these species were studied after quinacrine staining and Q⁺ material found to be restricted to the polytene fourth chromosomes, with the exception of D. orena which possesses considerable Q⁺ material in its chromocentre. These findings are discussed in the light of other studies of karyotype evolution in the genus Drosophila.     

An integrative approach to characterize Malagasy bats of the subfamily Vespertilioninae Gray, 1821, with the description of a new species of Hypsugo

Although important advances have been made in recent years in the taxonomy of different families and subfamilies of Malagasy bats, those belonging to the Vespertilioninae remain partially unresolved. Herein using a mitochondrial marker (cytochrome b) as the point of departure for 76 specimens of Malagasy vespers and appropriate African taxa, we diagnose the six taxa of this subfamily on the island by overlaying different morphological and bioacoustic characters on the clade structure of sequenced animals. The species include: endemic Neoromicia matroka, which is sister to African N. capensis; endemics N. malagasyensis and N. robertsi, which form sister species; a member of the genus Hypsugo, which is sister to African H. anchietae and described herein as new to science; Pipistrellus hesperidus for which Madagascar animals are genetically close but distinct from African populations of the same species; and endemic P. raceyi, which shows segregation of eastern (mesic) and western (dry) populations and its sister species relationships are unresolved. While the external and craniodental measurements, as well as bioacoustic variables, allow only partial differentiation of these six species of Vespertilioninae, molecular characters provide definitive separation of the taxa, as do male bacular morphology. © 2015 The Linnean Society of London     

GENETIC VARIABILITY AND MOLECULAR PHYLOGENY OF DINOPHYSIS SPECIES (DINOPHYCEAE) FROM NORWEGIAN WATERS INFERRED FROM SINGLE CELL ANALYSES OF rDNA1

The objectives of this study were to determine rDNA sequences of the most common Dinophysis species in Scandinavian waters and to resolve their phylogenetic relationships within the genus and to other dinoflagellates. A third aim was to examine the intraspecific variation in D. acuminata and D. norvegica, because these two species are highly variable in both morphology and toxicity. We obtained nucleotide sequences of coding (small subunit [SSU], partial large subunit [LSU], 5.8S) and noncoding (internal transcribed spacer [ITS]1, ITS2) parts of the rRNA operon by PCR amplification of one or two Dinophysis cells isolated from natural water samples. The three photosynthetic species D. acuminata, D. acuta, and D. norvegica differed in only 5 to 8 of 1802 base pairs (bp) within the SSU rRNA gene. The nonphotosynthetic D. rotundata (synonym Phalacroma rotundatum[Claparède et Lachmann] Kofoid et Michener), however, differed in approximately 55 bp compared with the three photosynthetic species. In the D1 and D2 domains of LSU rDNA, the phototrophic species differed among themselves by 3 to 12 of 733 bp, whereas they differed from D. rotundata by more than 100 bp. This supports the distinction between Dinophysis and Phalacroma. In the phylogenetic analyses based on SSU rDNA, all Dinophysis species were grouped into a common clade in which D. rotundata diverged first. The results indicate an early divergence of Dinophysis within the Dinophyta. The LSU phylogenetic analyses, including 4 new and 11 Dinophysis sequences from EMBL, identified two major clades within the phototrophic species. Little or no intraspecific genetic variation was found in the ITS1–ITS2 region of single cells of D. norvegica and D. acuminata from Norway, but the delineation between these two species was not always clear.     

Variation of wing shape in the Drosophila virilis species group (Diptera: Drosophilidae)

Wing shape variation was analysed with geometric morphometric methods in 17 laboratory strains, representing 11 closely related species (including two subspecies) of the Drosophila virilis group: D. virilis, D. lummei, D. novamexicana, D. americana americana, D. americana texana, D. montana, D. lacicola, D. flavomontana, D. borealis, D. littoralis, D. ezoana and D. kanekoi. Overall shape estimated using Procrustes coordinates of 14 landmarks was highly variable among strains and very similar in females and males. The landmarks in the distal part of the wing showed higher variation across strains than those in the proximal part. Procrustes distances between species were not consistent with phylogenetic distances previously suggested for the virilis group. Moreover, Procrustes distances between strains within species and within two major phylads (virilis and montana) were comparable with those between species and between phylads, respectively. The most different from other members of the group was the endemic D. kanekoi species, currently viewed as separate subphylad within the montana phylad. Allometric effects were found to be partly responsible for shape differences between the strains. Three most significant shape transformations were considered using the relative warp analysis and the strains were ordinated in accordance with transformation values. The pattern of relative warp scores could be easily interpreted only for the third warp explaining about 13% of shape variation. It separated the largest species, D. montana, D. ezoana and D. kanekoi, from other ones and was mainly associated with shape changes in the proximal region of the wing. The results of the present work suggest that wing shape in the virilis species group is not related to the speciation process. The observed proximal‐distal contrasts and allometric effects are in agreement with data of other studies, in which wing shape variation was analysed within Drosophila species.     

Predator satiation and extreme mast seeding in 11 species of Chionochloa (Poaceae)

Variation in annual flowering effort is described for 16 long datasets from 11 species of Chionochloa (Poaceae) in New Zealand. All populations exhibited extreme mast seeding. The most variable species was C. crassiuscula (coefficient of variation, CV=3.02) over 26 years at Takahe Valley, Fiordland, which is the highest published CV we know of worldwide. The other populations also had high CVs (lowest CV=1.42, mean CV=1.84) which were higher than for other well‐studied genera such as Picea, Pinus and Quercus. There were also frequent years of zero flowering (mean across all populations was 37.2% zero years; maximum 53% for C. rubra and C. crassiuscula over 19 years) whereas zero years are rare in other published masting datasets.Flowering was highly synchronous among species within a site (mean r=0.886), and also (though significantly less so) among sites. Among sites, synchrony was not significantly higher within‐species (mean r=0.711) than between‐species (r=0.690). Warm summer temperatures led to heavy flowering the following summer. Flowering synchrony increased with increasing synchrony in local deseasonalised summer temperatures, and decreased with increasing distance between sites.Mast seeding has been shown in Chionochloa to reduce losses to specialist flower or seed predators. Among‐species synchrony may be adaptive if species share a common seed predator. Developing seeds of at least 10 Chionochloa species are attacked by larvae of an undescribed cecidomyiid. In Takahe Valley, where masting is most pronounced, cecidomyiids attacked all six Chionochloa species in all four years studied. Mean annual losses were almost constant (10.0 to 13.4%) while flowering effort varied 100‐fold. The invariant losses are consistent with other evidence that the cecidomyiid may have extended diapause, which would make it harder to satiate by mast seeding. We hypothesise that one possible factor favouring such extremely high levels of mast seeding in Chionochloa is that its seed predator is very hard to satiate.     

Planktonic bloom of an introduced species of Polysiphonia (Ceramiales,Rhodophyta) along the coast of North Carolina,USA

Analysis was made of the species composition, egg number per female and the size-frequency of Amphipoda living on the dominating submerged macrophytes (Potamogeton perfoliatus and Myriophyllum spicatum) at 10 sampling stations of the northern and southern shoreline of Lake Balaton. The dominating Amphipoda at each sampling station was Corophium curvispinum (85.9–99.8%, mean: 96.6%). Besides this, two other species — Dikerogammarus haemobaphes and D. villosus — were also found in the samples. The two Dikerogammarus species were found in highest percentage near Keszthely (14.1 %); at the other places studied they were under 5%. The number of Amphipoda individuals per g macrophyte dry weight ranged from 5 to 574; the lowest value was found near Keszthely, the highest near B. Mária. The developmental stages of the C. curvispinum population differ in different parts of Lake Balaton: the adult (male and female) specimens occurred in highest percentage near Keszthely. The mean number of eggs per C. curvispinum female ranged from 2.4 to 6.3, showing differences at the different sampling stations. Regarding the two Dikerogammarus species, there were many more D. haemobaphes than D. villosus individuals at almost every station (mean: 75%). The mean number of eggs per egg-carrying female of D. haemobaphes was 11.7, being 19.1 for D. villosus.The total biomass of amphipods (in mg animal dry weight/g macrophyte dry weight) ranged from 1.2 to 59.8. The lowest value was observed near Keszthely (the most hypertrophic basin of Lake Balaton), the highest value near B. Maria