Why be cryptic? Choice of host urchin is not based on camouflage in the caridean shrimp Gnathophylloides mineri

The caridean shrimp Gnathophylloides mineri lives among the spines of various species of sea urchins. The shrimp has cryptic coloration that closely matches the coloration of the Caribbean urchin Tripneustes ventricosus. Despite this camouflage, in Jamaica, G. mineri is three times more abundant on the urchin Lytechinus variegatus than on T. ventricosus. L. variegatus exhibits more pronounced covering behavior than T. ventricosus. In laboratory choice experiments, the shrimp exhibited no preference between live, uncovered T. ventricosus or L. variegatus. Similarly, there was no preference between models (the tests, with spines attached, of hollowed out urchins) of T. ventricosus or L. variegatus without cover, or between models of T. ventricosus or L. variegatus with switched cover (i.e., each model was covered with the debris that had belonged to its partner when collected). There was, however, a significant preference for L. variegatus models with their natural covering over T. ventricosus with their natural covering. The shrimp may prefer L. variegatus with its extensive covering over T. ventricosus with extensive covering because the spines of the former are typically erect, as opposed to the spines of T. ventricosus, which usually lay flat across the test and would not give the shrimp much room to maneuver under the debris layer. Our study indicates that despite effective morphological and behavioral traits that render an organism highly cryptic, other, more effective, means of concealment may undermine the usefulness of this crypsis.     

Abundance and life cycle of Zonocerus variegatus (Orthoptera: Pyrgomorphidae) in the humid forest zone of southern Cameroon

Weekly captures from January 2000 to January 2002 enabled us to study the abundance and life cycle of the variegated grasshopper, Zonocerus variegatus (Orthoptera: Pyrgomorphidae), in the humid forest zone of Southern Cameroon. We found that Z. variegatus was present throughout the year in the forest reserve and the human‐influenced zones of Yaounde and Mbalmayo in two univoltine populations, which had unequal abundance and durations. The separation of the two populations was clearer in the Yaounde and Mbalmayo developed zones than in the Mbalmayo forest reserve (undeveloped zone). The abundance of Z. variegatus varied according to the post‐embryonic stage, sex, year and season. Hatching and coupling took place during the dry and rainy seasons, whereas oviposition occurred only in the rainy season. In Cameroon, the type of life cycle of Z. variegatus observed in the humid forest zone of the south is different from that of the “Sudanian and Sahelian” zones.     

Speciation on the coasts of the new world: phylogeography and the evolution of bindin in the sea urchin genus Lytechinus

Abstract Beginning with E. Mayr's study in 1954, tropical sea urchins have played an important role in studies of speciation in the sea, but what are the processes of cladogenesis and divergence that give rise to new species in this group? We attempt to answer this question in the genus Lytechinus. Unlike the majority of other tropical sea urchin genera, which have circumtropical distributions, Lytechinus is mostly confined to the tropics and subtropics of the New World. We sequenced a region of mitochondrial cytochrome oxidase I and the entire molecule of nuclear bindin (a sperm gamete recognition protein) of nearly all species in the genus, and we assayed isozymes of three partially sympatric closely related species and subspecies. We found that in both mitochondrial DNA (mtDNA) and in bindin the genus Lytechinus is paraphyletic, encompassing Sphaerechinus granularis as the sister species of L. euerces. The rest of the species are arranged in an Atlantic clade composed of L. williamsi and L. variegatus, and a Pacific clade containing L. anamesus, L. pictus, L. semituberculatus, and L. panamensis. Divergence between these clades suggests that they were separated no later than the closure of the Isthmus of Panama, and possibly before this time. Our data confirm that L. anamesus and L. pictus from California are a single species, and provide no evidence of differentiation between L. variegatus variegatus from the Caribbean and L. variegatus atlanticus from Bermuda. Lytechinus variegatus variegatus mtDNA is distinct from that of L. variegatus carolinus from the North American seaboard and the Gulf of Mexico, whereas their bindins are very similar. However, there is clear evidence of introgression of mtDNA between the two subspecies and they share alleles in all sampled isozyme loci. Lytechinus williamsi from the Caribbean shares mtDNA haplotypes with L. variegatus variegatus, and they also share isozymes in all assayed loci. Their bindin, however, is distinct and coalesces within each morphospecies. A private clade of mtDNA in L. williamsi may be indicative of former differentiation in the process of being swamped by introgression, or of recent speciation. Recent sudden expansions in effective population size may explain the predominance of a few mitochondrial haplotypes common to the two species. Despite the high divergence of bindin (relative to differentiation of mtDNA) between L. variegatus and L. williamsi, comparison of amino acid replacement to silent substitutions by various methods uncovered no evidence for positive selection on the bindin of any clade of Lytechinus. With the possible exception of L. williamsi and L. variegatus, our results are consistent with a history of allopatric speciation in Lytechinus. The molecular results from Lytechinus, along with those of other similar studies of sea urchins, suggest that the general speciation patterns deduced in the middle of last century by Mayr from morphology and geography have held up, but also have uncovered peculiarities in the evolution of each genus.     

The sea urchin Lytechinus variegatus lives close to the upper thermal limit for early development in a tropical lagoon

Thermal tolerance shapes organisms' physiological performance and limits their biogeographic ranges. Tropical terrestrial organisms are thought to live very near their upper thermal tolerance limits, and such small thermal safety factors put them at risk from global warming. However, little is known about the thermal tolerances of tropical marine invertebrates, how they vary across different life stages, and how these limits relate to environmental conditions. We tested the tolerance to acute heat stress of five life stages of the tropical sea urchin Lytechinus variegatus collected in the Bahía Almirante, Bocas del Toro, Panama. We also investigated the impact of chronic heat stress on larval development. Fertilization, cleavage, morula development, and 4‐armed larvae tolerated 2‐h exposures to elevated temperatures between 28–32°C. Average critical temperatures (LT₅₀) were lower for initiation of cleavage (33.5°C) and development to morula (32.5°C) than they were for fertilization (34.4°C) or for 4‐armed larvae (34.1°C). LT₅₀ was even higher (34.8°C) for adults exposed to similar acute thermal stress, suggesting that thermal limits measured for adults may not be directly applied to the whole life history. During chronic exposure, larvae had significantly lower survival and reduced growth when reared at temperatures above 30.5°C and did not survive chronic exposures at or above 32.3°C. Environmental monitoring at and near our collection site shows that L. variegatus may already experience temperatures at which larval growth and survival are reduced during the warmest months of the year. A published local climate model further suggests that such damaging warm temperatures will be reached throughout the Bahía Almirante by 2084. Our results highlight that tropical marine invertebrates likely have small thermal safety factors during some stages in their life cycles, and that shallow‐water populations are at particular risk of near future warming.     

The first records of Stylodrilus heringianus (Oligochaeta: Lumbriculidae) from the Southern Hemisphere

Abstract

The oligochaete family Lumbriculidae is well represented in the Northern Hemisphere, but for the Southern Hemisphere only Lumbriculus variegatus (Müller) is recorded, from Africa, Australia, and New Zealand; no species are known from South America (Brinkhurst & Jamieson 1971). According to Brinkhurst (1971), L. variegatus may be a recent introduction to New Zealand, where it is now widely distributed in a range of inland waters.     

Characterization of serine proteases of Lumbriculus variegatus and their role in regeneration

Serine proteases, ubiquitous enzymes known to function in digestion and immune protection in both vertebrates and invertebrates and implicated in regeneration in some species, were investigated in the California blackworm, Lumbriculus variegatus. Several serine proteases, rather than a single enzyme with broad specificity, were present in tissue extracts from the worms. Extracts were treated with a fluorescein‐labeled peptide chloromethyl ketone that specifically binds to trypsin/thrombin‐like proteases. Denaturing gel electrophoresis of labeled extracts showed several serine proteases with their molecular weight ranging 28,000–38,000 daltons. The trypsin/thrombin‐like activity was localized, using the fluorescein‐conjugated reagent, to the pharynx and digestive tract of L. variegatus. Movement of cells labeled by the reagent into regenerating tissues suggests that some differentiated endodermal tissues were used for reformation of digestive structures during regeneration in L. variegatus. The types of serine proteases in the extracts were further characterized by inhibitor studies. Presence of plasmin‐like activity was indicated by degradation of fibrin by tissue homogenates from the worms and the inhibitory effect of aprotinin on enzymes in these extracts. The ability of L. variegatus extracts to generate clots when incubated with rabbit plasma and partial inhibition of extract activity by phenylmethylsulfonyl fluoride and hirudin indicated presence of thrombin‐like activity. Consistent with the detection of trypsin, chymotrypsin, and plasmin‐like enzymes in the extracts was partial inhibition of L. variegatus serine protease activity by aminoethyl benzenesulfonyl fluoride and soybean trypsin inhibitor. Selective inhibition of chymotrypsin‐like activity by N‐tosyl‐l ‐phenylalanine chloromethyl ketone and chymostatin as well as trypsin‐like activity by N‐tosyl‐l ‐lysine chloromethyl ketone was observed. A potential role during regeneration for serine proteases is suggested by blockage of formation of head and tail structures by aminoethyl benzenesulfonyl fluoride, an inhibitor of these proteases.     

The relationship of diet to growth and ammonium excretion in salt marsh fish

Synopsis Detritus is an abundant but poor quality food source for consumers in salt marsh ecosystems. Here we present results of feeding experiments to determine the ability of Fundulus heteroclitus, Cyprinodon variegatus, and Mugil cephalus, three major detritivores in Great Sippewissett Marsh, Massachussetts, to assimilate detritus and use it for growth. C. variegatus, the sheepshead minnow, gained weight on a detrital diet, but F. heteroclitus, the marsh killifish, and juvenile M. cephalus, the striped mullet, lost weight and suffered high mortality on detrital diets. C. variegatus is a herbivore with morphological adaptations for ingesting plant material. F. heteroclitus is a carnivore poorly suited to effectively assimilate detritus from the diet. Although adult M. cephalus are adapted for ingesting and assimilating detrital material, the young may lack these adaptations and thus do not assimilate detritus. C. variegatus excretes ammonium at a lower rate than F. heteroclitus when fed animal food, or when starved for short periods of time. This protein sparing effect could be crucial for survival when detritus is the only food available at certain times of the year. While both C. variegatus and M. cephalus are visitors in the marsh and may leave to exploit food sources elsewhere, F. heteroclitus is a year-round resident and is the most abundant species of fish in the marsh. Yet when high quality food sources become scarce in late summer and fall, detritus, although plentiful, is apparently not a suitable alternative.To whom all correspondences should be addressed.     

The Pre-nervous Serotonergic System of Developing Sea Urchin Embryos and Larvae: Pharmacologic and Immunocytochemical Evidence

Forty serotonin-related neurochemicals were tested on embryos and larvae of Lytechinus variegatus and other sea urchin species. Some of these substances (agonists of 5-HT₁ receptors, antagonists of 5-HT₂, 5-HT₃ or 5-HT₄ receptors, and inhibitors of the serotonin transporter, SERT) perturbed post-blastulation development, eliciting changes in embryonic/larval phenotypes typical for each class of receptor ligand. These developmental malformations were prevented completely or partially by serotonin (5-HT) or 5-HT analogs (5-HTQ, AA-5-HT), providing evidence for the putative localization of cellular targets. Immunoreactive 5-HT, 5-HT receptors and SERT were found in pre-nervous embryos and larvae of both L. variegatus and Strongylocentrotus droebachiensis. During gastrulation, these components of the serotonergic system were localized to the archenteron (primary gut), mesenchyme-like cells, and often the apical ectoderm. These results provide evidence that pre-nervous 5-HT may regulate early events of sea urchin embryogenesis, mediated by 5-HT receptors or the 5-HT transporter.     

Impact of inter‐ and intra‐specific competition among larvae on larval,adult, and life‐table traits of Aedes aegypti and Aedes albopictus females

1. Few studies have taken a comprehensive approach of measuring the impact of inter‐ and intra‐specific larval competition on adult mosquito traits. In this study, the impact of competition among Aedes aegypti (L.) and A. albopictus (Skuse) was quantified over the entire life of a cohort. 2. Competitive treatments affected hatch‐to‐adult survivorship and the development time to adulthood of females for both species but affected the median wing length of females only for A. albopictus. Competitive treatments had no significant effect on the median adult female longevity nor were there any effects on other individual traits related to blood feeding and reproductive success. 3. Analysis of life table traits revealed no effect of competitive treatment on the net reproductive rate (R₀) but there were significant effects on the cohort generation time (T_c) and the cohort rate of increase (r) for both species. 4. Inter‐ and intra‐specific competition among Aedes larvae may produce individual and population‐level effects that are manifest in adults; however, benign conditions may enable resulting adults to compensate for some impacts of competition, particularly those affecting blood‐feeding success, fecundity, and the net reproductive rate, R₀. The effect of competition, therefore, affects primarily larva‐to‐adult survivorship and the larval development time, which in turn impacts the cohort generation time, T_c, and ultimately the cohort rate of increase, r. 5. The lack of effects of the larval rearing environment on adult longevity suggests that effects on vectorial capacity owing to longevity may be limited if adults have easy access to sugar and bloodmeals.     

Behavior,Growth, and Reproduction of Lumbriculus Variegatus (Oligochaetae) in Different Sediment Types

Lumbriculus variegatus is an oligochaete widely used in sediment toxicity tests. The locomotory behavior of adults from a normal and a clone population was studied in the Multispecies Freshwater Biomonitor? along with growth and reproduction to determine how different sediment types may affect this worm and forced clones during testing. Four different sand size classes were established by sieving: fine (< 1 mm), medium (1 < × < 2 mm), coarse (> 2 mm), and whole sediment. Locomotory activity was highest in fine and then in coarse sediment, while in whole and medium sediment size classes worms grew and reproduced less, and had lower locomotory activity levels. Fine sediment (< 1 mm) should be used as the negative control in L. variegatus whole sediment toxicity tests. A clone population, generated by cutting all worms over six generations, showed lower locomotory activity levels than normal worms. Artificial cloning is not recommended for obtaining additional test organisms.     

Survival and reproduction of Liposcelis paeta (Pearman) (Psocoptera: Liposcelididae) when irradiated by electron beams

Electron beam irradiation has been evaluated for the survival and reproduction of Liposcelis paeta Pearman (Psocoptera: Liposcelididae). All effects increased with increasing doses from 50 to 1000 Gy when the electron energy was 2 MeV. Eggs were unable to develop into adults following a dose of 100 Gy. Complete (100%) mortality was achieved about 5 weeks after adult emergence from nymphs irradiated at 300 Gy, whereas 100% mortality of adults was achieved 9 weeks after irradiation at 300 Gy. The fecundity was greatly reduced to 1.82% of that of control when L. paeta adults were irradiated at 250 Gy. A dose of 300 Gy caused complete reproductive sterility in adults. These results suggest that the most susceptible stage was the egg stage, then nymph and adult stages. A dose of 300 Gy is suggested for quarantine treatment of commodities infested by L. paeta.     

Dim light at night prior to adolescence increases adult anxiety-like behaviors

Dim light at night (dLAN) disrupts circadian organization and influences adult behavior. We examined early dLAN exposure on adult affective responses. Beginning 3 (juvenile) or 5 weeks (adolescent) of age, mice were maintained in standard light–dark cycles or exposed to nightly dLAN (5 lx) for 5 weeks, then anxiety-like and fear responses were assessed. Hypothalami were collected around the clock to assess core clock genes. Exposure to dLAN at either age increased anxiety-like responses in adults. Clock and Rev-ERB expression were altered by exposure to dLAN. In contrast to adults, dLAN exposure during early life increases anxiety and fear behavior.     

The ontogeny of the olfactory system in ceratophryid frogs (Anura,Ceratophryidae)

The aquatic‐to‐terrestrial shift in the life cycle of most anurans suggests that the differences between the larval and adult morphology of the nose are required for sensory function in two media with different physical characteristics. However, a better controlled test of specialization to medium is to compare adult stages of terrestrial frogs with those that remain fully aquatic as adults. The Ceratophryidae is a monophyletic group of neotropical frogs whose diversification from a common terrestrial ancestor gave rise to both terrestrial (Ceratophrys, Chacophrys) and aquatic (Lepidobatrachus) adults. So, ceratophryids represent an excellent model to analyze the morphology and possible changes related to a secondary aquatic life. We describe the histomorphology of the nose during the ontogeny of the Ceratophryidae, paying particular attention to the condition in adult stages of the recessus olfactorius (a small area of olfactory epithelium that appears to be used for aquatic olfaction) and the eminentia olfactoria (a raised ridge on the floor of the principal cavity correlated with terrestrial olfaction). The species examined (Ceratophrys cranwelli, Chacophrys pierottii, Lepidobatrachus laevis, and L. llanensis) share a common larval olfactory organ composed by the principal cavity, the vomeronasal organ and the lateral appendix. At postmetamorphic stages, ceratophryids present a common morphology of the nose with the principal, middle, and inferior cavities with characteristics similar to other neobatrachians at the end of metamorphosis. However, in advanced adult stages, Lepidobatrachus laevis presents a recessus olfactorius with a heightened (peramorphic) development and a rudimentary (paedomorphic) eminentia olfactoria. Thus, the adult nose in Lepidobatrachus laevis arises from a common developmental ‘terrestrial’ pathway up to postmetamorphic stages, when its ontogeny leads to a distinctive morphology related to the evolutionarily derived, secondarily aquatic life of adults of this lineage.     

Phagostimulation of Lytechinus variegatus (Lamarck) (Echinodermata: Echinoidea)

Artificial agarose foods containing either starch, glycogen, carragheenan, alginate, casein, gelatin, albumin, or peptones at a concentration of 1% dry weight were not phagostimulatory. Artificial foods containing sugars, especially galactose, at a concentration of 0.005 M were phagostimulatory. Of the common amino acids, only L‐phenylalanine was phagostimulatory at this concentration. The initiation of feeding postures (movement of the spines, tube feet, peristome, and Aristotle's lantern) of Lytechinus variegatus was little affected by the concentration of plant extracts. Many aspects of this behavior were attributable to physical rather than chemical stimulation. Feeding rates of L. variegatus upon artificial agarose foods containing either Thalassia testudinum or Gracilaria verrucosa were directly dependent upon plant tissue concentration. All artificial agarose food‐items were initially moved to the mouth and fed upon, however the time spent feeding was directly dependent upon plant type and tissue concentration. Retention of the artificial food‐items upon the test after feeding was not influenced by plant type or tissue concentration. Differences in consumption of foods by L. variegatus are determined by the degree of persistence in feeding upon encountered items and not be selection before initiating feeding or by retention of food‐items for subsequent feedings.     

Critical periods in the life cycle and the effects of a severe spate vary markedly between four species of elmid beetles in a small stream

1. The chief objectives were: (i) to describe quantitatively the life cycles of four species of Elmidae, Elmis aenea, Esolus parallelepipedus, Oulimnius tuberculatus and Limnius volkmari; (ii) to use life tables to identify critical periods for survival in the life cycle of each species; (iii) to evaluate the immediate and longer‐term effects of a severe spate on densities of the four species. Monthly samples were taken over 63 months at two contrasting sites in a small stream: one in a deep section with macrophytes abundant, and the other in a shallow stony section. 2. There were five larval instars for O. tuberculatus, seven for L. volkmari and six for the other two species. The life cycle of each species took 1 year from egg hatching (chiefly in June for E. aenea and O. tuberculatus, and July for the other species) to pupation in the stream bank and a further year before the adults in the stream matured and laid their eggs. Mature adults were present in most months, but were rare or absent in January and February and attained maximum densities in April for O. tuberculatus and May for the other species. 3. Laboratory experiments provided data on egg hatching and pupation periods and the number of eggs laid per female. Life tables compared maximum numbers per square metre for key life‐stages. Within each species, mortality rates between adjacent life‐stages were fairly constant among six cohorts and between sites, in spite of large differences in numbers. The only exception for all species was the high adult, but not larval, mortality during a severe spate. 4. Standardised life tables, starting with 1000 eggs, identified key life‐stages with the highest mortality, namely the early life‐stages for E. aenea (36% mortality), start of the overwintering period to pupation for O. tuberculatus (41%) and L. volkmari (51%), start of pupation to the maximum number of immature adults for E. parallelepipedus (41%) and between the maximum numbers of immature and mature adults for O. tuberculatus (41%). Therefore, critical periods for survival in the life cycle differed between species, presumably because of their different ecological requirements. Similarly, the effects of the spate on adult mortality, and hence egg production, varied between species, being most severe and long‐term for E. aenea and O. tuberculatus, less severe for E. parallelepipedus and least severe with a rapid recovery for L. volkmari. Possible reasons for these discrepancies are discussed, but more data are required on the food and microhabitat requirements of the elmids before satisfactory explanations can be found.     

Population studies ofCavelerius saccharivorus Okajima (Heteroptera: Lygaeidae): Adult dispersal in relation to the density

Two adjacent stations (H and L) were set up to study movement of C. saccharivorus adults in sugarcane fields. At the beginning of the study the density of C. saccharivorus including all stages of development was quite different between the two. The density of the first generation adult on Station H was about 5 times that on Station L. The number of C. saccharivorus on both the stations became almost the same one month after the beginning of the study. At the beginning of the study macropterous adults were more numerous in Station H than in Station L. However percentage of macropterous adults on Station L increased after one month whereas that on Station H declined. About 2,000 marked adults were released on each station during the early period of the emergence of the first generation adult. Marked insects were recaptured on both the stations one month after the release. The adults released on the dense population (H) tended to disperse more actively than those on the scarce population (L). Marked macropterous adults moved more actively than brachypterous ones. The density related dispersal of adults was considered to be an important factor to regulate the population density.     

Adoptive transfer of dendritic cells modulates immunogenesis and tolerogenesis in a neonatal model of murine cutaneous leishmaniasis

We evaluated the adoptive transfer of DCs on Leishmania (L.) mexicana-infected neonatal BALB/c mice. DCs were isolated and purified from the spleens of the following donor groups: a) Adult BALB/c mice infected during adulthood with L. (L) mexicana; b) Adult BALB/c mice infected during neonatal life; c) Healthy neonatal BALB/c mice; d) Healthy adult BALB/c mice. A neonatal model of infection, generated after inoculation with 5 × 10⁵ promastigotes of L. (L) mexicana, was used as the infection control group. Sixteen hours after intraperitoneal transfer of DCs (1 × 10³, 1 × 10⁵, or 1 × 10⁶ cells/ml), neonatal recipient BALB/c mice were infected. The adoptive transfer of DCs diminished disease progression in neonatal mice. This reduction depends on the quantity and provenance of transferred DCs, since the effect was more evident with high numbers of DCs from adult mice infected during adulthood and healthy neonatal mice. Protection was significantly reduced in animals receiving DCs from healthy adult mice but it was absent in mice receiving DCs from adult mice infected during neonatal life. These results suggest that genetic susceptibility to Leishmania infection can be modified during neonatal life, and that the period of life when antigens are encountered is crucial in influencing the capacity of DCs to induce resistance or tolerance.     

Biology of Nomioides variegatus (Olivier) (Hymenoptera: Halictidae)

The nesting biology, life history and pollen foraging of the minute Nomioides variegatus (Olivier) is described and illustrated. All Nomioides biological studies are reviewed. Nesting and foraging were observed over two years in a sandy natural area in the Rhône River delta region of southern France. Nest and cell structure was obtained from soil blocks removed from the nesting area and examined in the laboratory. Females, which were on average only 4.2 mm long, nested solitarily in loose aggregations in areas free of vegetation. Cells were placed from 6 to 12 cm deep, each terminating a lateral burrow off the main burrow. Cell walls were lined with a water proof wax-like lining. The pollen-nectar provision was a flattened sphere. The posterior end of the egg was embedded on the dorsal surface of the provision. Larval and pupal development was rapid, proceeding to adults by August, the over-wintering stage. Pollen foraging patterns were analyzed from both pollen provisions and fecal material for different nests (3) and cells (8). Nomioides variegatus is polylectic, but individuals bees exhibited a high degree of foraging consistency for the provisioning of single cells. Eleven different pollen types representing 10 plant families were found. In 1996, Ecballium elaterium (Cucurbitaceae) was the dominant pollen present in all samples but it was absent in 1997. Tamarix gallica (Tamaricaeae) was the dominant pollen type in 1997 and absent in 1996. A third pollen, Centaurium (Gentianaceae) was present in both years and represented 70% of some samples.     

Development of polymorphic microsatellite markers in barfin flounder (<Emphasis Type="Italic">Verasper moseri</Emphasis>) and spotted halibut (<Emphasis Type="Italic">Verasper variegatus</Emphasis>) by the cross-species amplification

Barfin flounder (Verasper moseri) and spotted halibut (Verasper variegatus) are two commercially important flatfish species in the Northeast Asia. In the present study, we reported polymorphic microsatellite markers in V. moseri and V. variegatus by the cross-species amplification of microsatellite primers developed previously in two other related marine fish species. A total of 244 polymorphic microsatellite markers were selected for cross-species amplification in V. moseri and V. variegatus, of which 182 markers deriving from Atlantic halibut (Hippoglossus hippoglossus) and 62 markers deriving from Japanese flounder (Paralichthys olivaceus). A sample of 10 individuals were detected. As a result, a total of 67 loci showed polymorphisms in V. moseri, and 62 loci showed polymorphisms in V. variegatus, with the observed number of alleles per locus ranging from two to five in V. moseri, and from two to seven in V. variegatus, respectively. This paper provided more candidate microsatellite markers which could be useful for construction of genetic linkage maps, evaluation of population genetic structure and stock management of V. moseri and V. variegatus.     

Corn Stunt Spiroplasma in Dicotyledonous Plants

Corn stunt spiroplasma (CSS) was transmitted by the leafhopper vector Euscelidius variegatus (Kirschbaum) and produced symptoms on four dicotyledonous plant species, Sinapis alba L. (mustard), Pisum sativitm L. (pea), Raphanus sativus L. (radish) and Spinacia oleracea L. (spinach). The vectors became infective by microinjection with a broth culture of CSS. This insect also acquired CSS from infected mustard plants and transmitted it to healthy ones.