Ecomorphological comparisons of sagittae in Mullus barbatus and M. surmuletus

For both Mullus barbatus and M. surmuletus , the relationship between sagitta area (O), sulcus acusticus area (S) throughout postlarval growth was characterized by their negative allometric growth. The adjusted mean S: O ratio differed between the two species. This may be associated with the difference in size and shape of the sagittae, a difference in somatic growth, and differences in food and spatial niches. The inner ear of Mullus cannot be considered as specialized and the interaction of stimuli detected by the sensory barbels and the inner ear together could be a compensatory mechanism that helps in the food search.     

The foraging ecology of two pairs of congeneric demersal fish species: importance of morphological characteristics in prey selection

The feeding habits of two sympatric species pairs of demersal fish ( Mullus barbatus-Mullus surmuletus, Serranus cabrilla-Serranus hepatus ) which occupy the shallow coastal area (25–30 m) in Iraklion Bay were investigated from samples collected on a monthly basis (August 1990 to August 1992). Stomach content analyses revealed that all of them were carnivores, feeding mainly on benthic invertebrates, and that each species consumed a narrow range of prey species with no significant dietary overlap. The morphology of their feeding apparatus was compared to examine the effect of any morphological differences on food selection and resource partitioning between the fish species. The species could be distinguished on the basis of the size of their mouth gape, the number of gill rakers and the length of their intestine. This study shows that each species pair follows a different strategy segregating along food niche dimensions. In particular, M. barbatus and M. surmuletus segregate their feeding niche consuming different prey taxa with similar sizes whereas S. cabrilla and S. hepatus differ considerably with respect to the degree to which prey species contribute to their diets coupled with differences in mean prey sizes.     

Difference in diet and size‐related trophic level in two sympatric fish species,the red mullets Mullus barbatus and Mullus surmuletus,in the Gulf of Lions (north‐west Mediterranean Sea)

Stable‐isotope ratios (δ¹⁵N and δ¹³C) and diet of the red mullets Mullus barbatus and Mullus surmuletus were analysed in two zones differently subjected to the Rhône River runoff in the Gulf of Lions (north‐west Mediterranean sea) in May and October 2004. δ¹⁵N and δ¹³C increased significantly with fish size in M. barbatus in both zones and seasons, whereas no significant trend was evidenced in M. surmuletus. A clear size‐related shift in diet was observed in M. barbatus, with an increase in polychaete and shrimp consumption with size and a decrease in small crustacean consumption. In M. surmuletus, a diet shift was observed only between medium and large individuals. Large M. surmuletus preyed on shrimps, polychaetes, bivalves, ophiurids and amphipods, and ingested prey of lower mean mass than M. barbatus of similar size. Difference in size‐related increase in δ¹⁵N between the two mullid fish species were related to difference of trophic level of their main prey. Sub‐surface deposit‐feeding polychaetes, carnivorous polychaetes, shrimps and brachyurans presented higher δ¹⁵N values than bivalves, small crustaceans and ophiurids. The lower δ¹³C values observed in M. barbatus compared to M. surmuletus were related to a higher consumption of sub‐surface polychaetes in the former species. Significantly, lower δ¹³C were recorded in fishes collected off the Rhône River, particularly in spring, suggesting an influence of river inputs as a source of particular organic matter for mullids in this zone after the flooding season. Thus, these closely related sympatric fish species displayed diet divergences that were reflected in their stable isotopic signatures.     

Niche separation between colonizing and indigenous goatfish (Mullidae) along the Mediterranean coast of Israel

The present study assesses the resource partitioning between two Red Sea colonizers, the goldband goatfish Upeneus moluccensis and the brownband goatfish U. pori , and the two indigenous Mediterranean goatfishes, the red mullet Mullus barbatus and the striped mullet M. surmuletus , along the Mediterranean coast of Israel.
Niche separation was studied along three axes: habitat selection, feeding habits and spawning season. Habitat selection is the most significant parameter separating the species. The two colonizing species occupy a shallow habitat, U. pori dominating the primarily sandy bottom at 20–30 m and U. moluccensis at 40–50 m, at which depth the sea bottom becomes increasingly silty. Of the two indigenous species, M. barbatus is dominant in depths below 55 m, while M. surmuletus appears at low abundance in all depths.
Niche separation by feeding habits is much less evident. All four species feed primarily on macrurid crustaceans and thus the values of diet overlap are rather high (0·666≤ T ≤0·928). Prey size is not an important factor in niche separation. Young fishes (S.L>,115 mm) of all four species feed upon prey of similar size (20–160 mg). Among older individuals (S.L.>115 mm) three species continue to feed upon the same size prey, while U. moluccensis feeds upon considerably larger prey (600–2200 mg).
The difference between the spawning seasons of the colonizing vs indigenous species and consequent timing of benthic settling may contribute to niche separation.
The results of this study suggest that success in colonization by Red Sea goatfish may be due to the existence of unexploited niches in the eastern Mediterranean ecosystem.     

Exploitation patterns of the European hake Merluccius merluccius, red mullet Mullus barbatus and striped red mullet Mullus surmuletus in the western Mediterranean

The exploitation patterns of three target species ( Merluccius merluccius , L. 1758 , Mullus barbatus , L. 1758, Mullus surmuletus , L. 1758) of the western Mediterranean demersal fisheries were compared. The study was carried out in five ports along the Italian and Spanish coasts. These three species are fished simultaneously or sequentially by a number of gears, their use during the year being different depending on the area. The trawl catches dominated the landings, both in number and weight, but varied greatly during the year. The size ranges of specimens in the catches were in their major part different among the types of gear. Artisanal methods (gillnet and long line for M. merluccius , trammel net for Mullus spp.), used seasonally, contributed primarily to landings of larger, adult specimens, whereas trawl catches consisted mainly of smaller sized individuals, recently recruited to the fishery. In M. merluccius, individuals of less than 20 cm total length accounted for 80 to 95% of the annual catch in numbers, and between 15 and 60% of the catch in weight, depending on the port. This situation indicates a substantial over-exploitation and a high risk of long-term unsustainability in stock development and production.     

Taxonomic relationships between four species of the Mullidae family revealed by three genetic methods: allozymes, random amplified polymorpic DNA and mitochondrial DNA

Genetic distances were lower between Upeneus moluccensis and Pseudopeneus prayensis than between those species and Mullus barbatus and Mullus surmuletus . However, for allozymes, the two Mullus species were found genetically more distinct from U. moluccensis than from P. prayensis , but RAPD and mtDNA analysis showed the opposite. RAPDs revealed less interspecific divergence compared with allozymes and the results they produced were more consistent with mtDNA analysis. Although RAPDs did not add any supplementary taxonomic information, they proved valuable tools for quick and reliable species discrimination compared with allozymes and mtDNA.     

Hummingbird-Syndrome Traits, Breeding System, and Pollinator Effectiveness in Two Syntopic Penstemon Species

Red-flowered, tubular Penstemon barbatus and Penstemon pinifolius, which have probably adapted independently to hummingbird pollinators, coflower on recently burned high-elevation slopes in the Chiricahua Mountains in Arizona. Hummingbirds visit both species but visit P. barbatus at a higher rate. We compared several traits and asked whether the species differed in specialization for hummingbird pollination. The corollas of P. pinifolius were 30% narrower than those of P. barbatus, but they were similar in tube length. Although a narrower corolla appeared to decrease access by large insects, small halictid bees were the only common insect visitors, and they gathered nectar from both species. Species differences in nectar production rate and concentration were minor, being smaller than within-species differences between dry and rainy periods. Taller inflorescences and a wider corolla tube may contribute to greater hummingbird use of P. barbatus. Penstemon pinifolius was fully self-compatible and weakly autogamous, whereas P. barbatus was strongly self-incompatible and had a longer flower life. Exclusion of hummingbirds reduced seed set fourfold in both species, supporting the inference from morphology and rewards that hummingbirds are the primary pollinators. In the absence of hummingbirds, halictids increased the seed set of P. barbatus relative to exclusion of all visitors, but they did not increase the seed set of P. pinifolius. Despite sharing the basic set of hummingbird-syndrome traits, the two species differed in degree of investment in individual flowers and in adaptations for outcrossing.     

Differential selection on floral traits of Ipomopsis aggregata growing in contrasting environments

Interactions for pollination between co-flowering plant species have been hypothesized to shape the evolution of their floral traits, but this hypothesis has rarely been tested. I tested the prediction that the presence of a co-flowering plant species influences the strength and/or direction of pollinator-mediated selection on floral traits. I measured phenotypic selection via female fitness on four floral traits of Ipomopsis aggregata in five populations. Three contained only conspecifics ( I only ) and two also contained the co-flowering species Penstemon barbatus ( P + I ). Directional selection via fruits/plant on corolla length and width differed in both strength and direction between P + I and I only populations. On average, selection on corolla length and width (1) was stronger in P + I than I only populations and (2) was consistently negative in P + I populations, but consistently positive in I only populations. However, these differences in selection on I . aggregata between P + I and I only populations were not caused by interactions for pollination with P . barbatus . Although plants in P + I populations received approximately 31% less conspecific pollen/flower than plants in I only populations, this difference in pollination did not translate into differences in reproductive success, which indicates that P . barbatus and I . aggregata do not strongly compete for pollination. In addition, selection via fruits/plant and conspecific pollen deposited/flower was not congruent. For example, selection on corolla length via pollen/flower was uniformly positive and did not differ between P + I and I only populations. These data suggest that the presence of P . barbatus does influence selection on floral traits of I . aggregata , but not by influencing pollination. Instead, differences in selection between P + I and I only populations appear to be the result of post-pollination modification of selection by a factor correlated with the presence of P . barbatus .     

Habitat related differences in lipid reserves of some exploited fish species in the north‐western Mediterranean continental shelf

At a large‐scale, the lipid content in the muscle of Pagellus acarne and Pagellus erythrinus was higher in the Gulf of Lions than in the Catalan Sea. Furthermore, there was a significant effect of depth on lipid content of Mullus barbatus, Mullus surmuletus and P. acarne , fishes with the highest lipid levels inhabiting the shallowest parts of the Gulf of Lions (all three species) and the Catalan Sea (last two species). At a small‐scale, the study revealed differences in the condition of Diplodus sargus sargus between protected (Natural Park of Cap de Creus) and the unprotected habitats. Total lipid content in the muscle of D. s. sargus during spawning was higher within the protected area than in adjacent unprotected rocky areas. Because lipids play a critical role in the health, growth and reproduction of fishes, results from this study support the relative importance of some habitats (shallow v . deeper parts of the continental shelf, the Gulf of Lions v . the Catalan Sea, and the protected bottom areas of the Natural Park of Cap de Creus v . the unprotected bottom areas) for the productivity of different Mediterranean fishes.     

Behavioural response of Mullus surmuletus to habitat modification by the invasive macroalga Caulerpa taxifolia

Densities of red mullet Mullus surmuletus have declined since 1996 at Cap Martin, Alpes‐Maritimes, France, following colonization by Caulerpa taxifolia . Foraging M. surmuletus were rarely observed over C. taxifolia or the seagrass Posidonia oceanica , but were observed over bare sand and endemic macroalgae. Within colonized sites (where the mean cover of C. taxifolia was 30–100%), fish were concentrated on areas with low cover of C. taxifolia (<21%). A difference in the frequency of observations of foraging groups (17%) was observed between sites with and without C. taxifolia . The observed patterns were probably due to a physical barrier to foraging that is presented by meadows of C. taxifolia . Changes to habitat structure that occur when the substratum is colonized by C. taxifolia influence the accessibility to benthic food resources, and consequently the foraging activities of fish that feed on benthic invertebrates. The decline in density of M. surmuletus at Cap Martin could be the result of fish emigration from colonized sites (unfavourable to the species) to uncolonized sites.     

Foraging interactions among three benthic fish in a Posidonia oceanica reef lagoon along the Tyrrhenian Coast

Three benthic predators Coris julis, Symphodus cinereus and Mullus surmuletus in a Posidonia oceanica reef lagoon of the Tyrrhenian coast had a broad diet, including hard-bodied invertebrates such as crustaceans and molluscs, but revealed consistent interspecific differences. Diet overlap was greater between C. julis and M. surmuletus in comparison to other combinations. All three species were diurnal feeders, but with diVerent daily patterns of foraging based on diVerent prey availability. There was a general spatio-temporal correlation in non-foraging activity among the three species, but foraging activity was correlated only between C. julis and the other two species, but not between S. cinereus and M. surmuletus .There was heterospecific aggregation during foraging between C. julis and M. surmuletus , and possibly a scrounger–producer relationship between them. Fights between C. julis specimens related to foraging activity were common, but not between species. These results support the view that diVerences in spatio-temporal organization of activity, and interactions during foraging, can contribute to resource partitioning among syntopic populations of fish belonging to the same trophic group.     

热带雨林不同生态习性树种幼苗光合作用和抗氧化酶对生长光环境的反应

于雨季研究了西双版纳热带雨林后期演替树种思茅木姜子(Litsea pierrei var.szemaois)、五桠果叶木姜子(L．alilleniifolia)和先锋树种毛果桐(Mallotus barbatus)幼苗的光合、荧光特征和抗氧化酶等对3种光水平(50％、25％和8％)的适应特性。结果表明,毛果桐的最大光合速率(Pmx)随光水平升高呈增加趋势,而两种木姜子则在50％光水平下Pmax最小,Fv／Fm的日变化表明,3个种在25％和50％光水平下发生可逆光抑制,两种木姜子较重,50％光水平下,五桠果叶木姜子受到长期光抑制．思茅木姜子和毛果桐的丙二醛(MDA)和H2O2含量,以及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)活性随光水平升高而增加,表明光水平升高,致使植物受光胁迫的影响加剧,增强抗氧化酶系统则减轻了其伤害,两种木姜子的濒危现状可能和它们对强光生境的适应性较差有一定关系。     

Review of Papillostrongylus Johnston & Mawson, 1939 (Nematoda: Strongyloidea) from wallabies and kangaroos (Marsupialia: Macropodidae) using morphological and molecular techniques,with the description of P. barbatus n. sp.

The strongyloid nematode genus Papillostrongylus Johnston & Mawson, 1939, from kangaroos and wallabies, is reviewed using morphological and molecular methods. P. labiatus Johnston & Mawson, 1939 is re-described from material from the type-host, the black-striped wallaby Macropus dorsalis, from eastern Queensland, Australia, in which it is a relatively common parasite. Additional records from M. parryi and Thylogale thetis are confirmed and considered to represent examples of host-switching. A geographically disjunct population of the nematode species occurs in M. bernardus and Petrogale brachyotis in Arnhem Land, Northern Territory, but assessment of its status requires additional material. Nematodes from M. rufus, M. giganteus, M. fuliginosus and M. robustus from inland regions of Australia, formerly attributed to P. labiatus, are here assigned to a new species, P. barbatus, distinguished by the presence of an external leaf-crown, larger size, by greater spicule length in the male and by a sinuous vagina in the female. Additional hosts of P. barbatus n. sp. are Petrogale assimilis and Pet. lateralis purpureicollis. Sequence analyses of the second internal transcribed spacer of ribosomal DNA (ITS-2) also showed that P. barbatus n. sp. differed at 40 (16.7%) of the 240 alignment positions when compared with P. labiatus. Most of these interspecific sequence differences occurred in loops or bulges of the predicted precursor rRNA secondary structure, or represented partial or total compenstory base pair changes in stems.     

RFLP Analysis of Mitochondrial DNA to Evaluate Genetic Variation in Striped Red Mullet (Mullus surmuletus L.) and Red Mullet (Mullus barbatus L.) Populations

The genetic differentiation of striped red mullet (Mullus surmuletus) and red mullet (Mullus barbatus) was investigated in 6 Mediterranean populations of each species by means of restriction fragment length polymorphism analysis of mitochondrial DNA. Three segments amplified by polymerase chain reaction (control region, COI, and 12S–16S ribosomal RNA) were digested with 20 restriction endonucleases, revealing 71 haplotypes for M. surmuletus and 30 for M. barbatus. For the two species nucleotide diversity was equally distributed within and among populations, leading to N _ST values of 0.545 and 0.500 for M. surmuletus and M. barbatus, respectively. However, intrapopulation and interpopulation genetic structuring appeared to be much higher for M. surmuletus than for M. barbatus (1.88% vs. 0.46% of mean intrapopulation nucleotide diversity; 1.94% vs. 0.47% of mean interpopulation nucleotide diversity; 0.055% vs. 0.002% of net interpopulation divergence). Furthermore, 81.69% of the haplotypes observed for M. surmuletus were unique, whereas 70.29% of M. barbatus individuals were grouped in 3 common haplotypes. Given that fishing pressure and population sizes are similar for both species, this differentiation could be attributed to differences in biological parameters and life histories between the two species, coupled with oceanographic conditions prevailing in the studied area. Received July 25, 2000; accepted December 29, 2000     

西班牙加泰罗尼亚CERDANYA地区晚中新世轮藻植物LYCHNOTHAMNUS BARBATUS的分类学与古生态学意义

轮藻纲植物Lychnothamnus barbatus的化石在西班牙加泰罗尼亚地区比利牛斯山脉东部Cerdanya盆地上中新统(Turolian阶)发现。通过与现生L．barbatus的比较研究,发现两者在藏卵器大小方面存在较大差别,据此建立新亚种Lychnothamnus barbatus ssp．megalicarpus subsp．nov．,其藏卵器的各项特征均与器官属Rhabdochara(Madler)Grambast一致,证实两者为同物异名。Lychnothamnus barbatus在盆地上部湖相沉积层中的大量存在,表明湖盆演化史后期发生过营养状况由富营养化向贫营养化转变的现象。     

A comparison of glycan expression and adhesion of mouse-adapted strains and clinical isolates of Helicobacter pylori

The role of Mycoplasma pneumoniae infection as a trigger for asthma exacerbations is well supported in previous studies. This study was designed to investigate the role of M. pneumoniae infection in acute exacerbation of asthma in children. A total of 150 patients (110 males, 40 females) were studied and immunoglobulin M (IgM) antibodies to M. pneumoniae were detected by enzyme-linked immunosorbent assay (ELISA), and PCR amplification was performed for the P1 gene to associate M. pneumoniae infection with asthma. As compared with 33 children with asthma, only two of the control subjects had positive IgM titers for M. pneumoniae , which was statistically significant ( P =0.002). A total of 15 children with asthma were positive by PCR for the P1 gene while none of the controls had a positive PCR. Of these positive cases, 24 cases were positive only by ELISA, six were positive only by PCR and nine patients were found to be positive by both ELISA and PCR. All the clinical characteristics of the patients at baseline were comparable between the moderate and the severe group of patients statistically, except for the peak expiratory flow rate. Mycoplasma pneumoniae infection was found to have a significant association with acute exacerbation in the moderate group of asthma patients by PCR ( P =0.01). These data suggest that M. pneumoniae infection may contribute to asthma exacerbation.     

The interactive effects of climate, life history, and interspecific neighbours on mortality in a population of seed harvester ants

Abstract.  1. Fifteen years of census data from a population of the red harvester ant ( Pogonomyrmex barbatus ), 5 years of census data from populations of Aphaenogaster cockerelli and Myrmecocystus mimicus at the same site, and long-term precipitation data from a nearby weather station were used to examine how nearest interspecific neighbours, climate, and life history influence P. barbatus colony mortality.
2. It was found that more P. barbatus colonies die following dry summers than following wet summers, but there is no relationship between the establishment of new colonies and rainfall.
3.  Aphaenogaster cockerelli , but not M. mimicus , nearest neighbours influence P. barbatus colony mortality in some years and for some ages.
4. The effects of nearest A. cockerelli neighbours are usually most severe following dry summers, when resource availability is reduced.     

沈阳市居民乙肝感染状况调查

对不同性别、年龄的沈阳市居民乙型肝炎病毒血清标志物进行检测,分析HBV感染状况。采集3 780名健康体检者血清标本检测乙肝5项、ALT和TBIL,统计分析后的结果显示:乙肝感染率为3.28%,不同性别间结果无明显差异(P>0.05),但不同年龄组间乙肝感染率有显著差异(P<0.01),41～50岁年龄组感染率是6.23%,30岁以下和50岁以上感染率较低,分别为2.94%和1.84%;1、4、5感染模式占总感染例数的69.4%,HBV感染者中ALT或TBIL单项升高及二者均升高者占22.6%。沈阳市居民乙肝感染率低于全国平均水平,慢性乙肝感染较多,肝功能与乙肝感染病程不呈平行关系,疫苗接种可有效预防乙肝感染。