Microsatellite Evidence for High Frequency of Multiple Paternity in the Marine Gastropod Rapana venosa

Background

Inferring of parentage in natural populations is important in understanding the mating systems of a species, which have great effects on its genetic structure and evolution. Muricidae, a large group (approximately 1,600 species) of marine gastropods, are poorly investigated in patterns of multiple paternity and sperm competition based on molecular techniques. The veined Rapa whelk, Rapana venosa, a commercially important muricid species with internal fertilization, is an ideal species to study the occurrence and frequency of multiple paternity and to facilitate understanding of their reproductive strategies.

Methodology/Principal Findings

We developed five highly polymorphic microsatellites in R. venosa and applied them to identify multiple paternity in 19 broods (1381 embryos) collected from Dandong, China. Multiple paternity was detected in 17 (89.5%) of 19 broods. The number of sires per brood ranged from 1 to 7 (4.3 on average). Of the 17 multiply sired broods, 16 (94.1%) were significantly skewed from equal paternal contributions, and had a dominant sire which was also dominant in each assayed capsule.

Conclusions

Our results indicate that a high level of multiple paternity occurs in the wild population of R. venosa. Similar patterns of multiple paternity in the 2–6 assayed capsules from each brood imply that fertilization events within the body of a female occur mostly (but not entirely) as random draws from a “well-but-not-perfectly blended sperm pool” of her several mates. Strongly skewed distributions of fertilization success among sires also suggest that sperm competition and/or cryptic female choice might be important for post-copulatory paternity biasing in this species.     

Molecular Evidence for High Frequency of Multiple Paternity in a Freshwater Shrimp Species Caridina ensifera

Background

Molecular genetic analyses of parentage provide insights into mating systems. Although there are 22,000 members in Malacostraca, not much has been known about mating systems in Malacostraca. The freshwater shrimp Caridina ensifera blue, is a new species belonging to Malacostraca which was discovered recently in Sulawesi, Indonesia. Due to its small body size and low fecundity, this species is an ideal species to study the occurrence and frequency of multiple paternity and to understand of how the low fecundity species persist and evolve.

Methodology/Principal Findings

In this study, we developed four polymorphic microsatellites from C. ensifera and applied them to investigate the occurrence and frequency of multiple paternity in 20 C. ensifera broods caught from Lake Matano, Sulawesi. By genotyping the mother and all offspring from each brood we discovered multiple paternity in all 20 broods. In most of the 20 broods, fathers contributed skewed numbers of offspring and there was an apparent inverse correlation between reproductive success of sires and their relatedness to mothers.

Conclusions/Significance

Our results in combination with recent reports on multiple paternity in crayfish, crab and lobster species suggests that multiple paternity is common in Malacostraca. Skewed contribution of fathers to the numbers of offspring and inverse correlation between reproductive success of sires and their relatedness to mothers suggest that sperm competition occurred and/or pre- and postcopulatory female choice happen, which may be important for avoiding the occurrence of inbreeding and optimize genetic variation in offspring and for persistence and evolution of low fecundity species.     

A laboratory study of host use by the cuckoo catfish <Emphasis Type="Italic">Synodontis multipunctatus</Emphasis>

The only known non-avian vertebrate obligate brood parasite is the cuckoo catfish (Synodontis multipunctatus), a Lake Tanganyikan endemic. The cuckoo catfish parasitizes Tanganyikan mouthbrooding cichlids, and under captive conditions, will also parasitize cichlids from other Rift Valley lakes. Here we examine the frequency of parasitism by the cuckoo catfish of Ctenochromis horei from Lake Tanganyika and three species from Lake Malawi and the greater Lake Victorian system in a laboratory setting. C. horei was parasitized significantly less (17%) than the allopatric species Haplochromis latifasciatus, Haplochromis nubilus, and Metriaclima estherae (combined parasitism rate of 28%). The lower rates of parasitism in C. horei may be due to differences in the mating ritual, oviposition (e.g., long periods of pseudo-spawning before actual oviposition), and behavioral adaptations (e.g., increased aggression towards the cuckoo catfish). The number of catfish eggs per parasitized brood was similar between C. horei, H. latifasciatus, H. nubilus, and M. estherae. Our results are comparable to findings from the field for C. horei parasitism frequency and number of cuckoo catfish per brood. We also analyzed the parasitism rate of the albino morph of Metriaclima zebra, a domestic strain. Parasitism rates and number of catfish per brood were the highest in the albino morphotype suggesting that the higher levels of parasitism may be related to lower aggressive behavior, lower visual acuity, or captive influence. Cuckoo catfish and mouthbrooding cichlids provide a model system for testing brood parasitism in a laboratory setting.     

Cladogenesis and reticulation in <Emphasis Type="Italic">Cuscuta</Emphasis> sect. <Emphasis Type="Italic">Denticulatae</Emphasis> (Convolvulaceae)

As traditionally circumscribed, Cuscuta sect. Denticulatae is a group of three parasitic plant species native to the deserts of Western USA (Cuscuta denticulata, Cuscuta nevadensis) and the central region of Baja California, Mexico (Cuscuta veatchii). Molecular phylogenetic studies confirmed the monophyly of this group and suggested that the disjunct C. veatchii is a hybrid between the other two species. However, the limited sampling left the possibility of alternative biological and methodological explanations. We expanded our sampling to multiple individuals of all the species collected from across their entire geographical ranges. Sequence data from the nuclear and plastid regions were used to reconstruct the phylogeny and find out if the topological conflict was maintained. We obtained karyotype information from multiple individuals, investigated the morphological variation of the group thorough morphometric analyses, and compiled data on ecology, host range, and geographical distribution. Our results confirmed that C. veatchii is an allotetraploid. Furthermore, we found previously unknown autotetraploid population of C. denticulata, and we describe a new hybrid species, Cuscuta psorothamnensis. We suggest that this newly discovered natural hybrid is resulting from an independent (and probably more recent) hybridization event between the same diploid parental species as those of C. veatchii. All the polyploids showed host shift associated with hybridization and/or polyploidy and are found growing on hosts that are rarely or never frequented by their diploid progenitors. The great potential of this group as a model to study host shift in parasitic plants associated with recurrent allopolyploidy is discussed.     

Evaluations of the Removal of <Emphasis Type="Italic">Varroa destructor</Emphasis> in Russian Honey Bee Colonies that Display Different Levels of <Emphasis Type="Italic">Varroa</Emphasis> Sensitive Hygienic Activities

The removal of Varroa destructor was assessed in Russian honey bee (RHB) colonies with known levels of Varroa Sensitive Hygienic (VSH) and brood removal activities. The expression of grooming behaviour using individual bees was also measured using three groups of RHB displaying different VSH levels: low hygiene (RHB-LH, < 35% VSH), medium hygiene (RHB-MH, 35–70%) and high hygiene (RHB-HH, > 70%). Italian colonies (5.43–71.62% VSH) served as control. Our results demonstrated, for the first time, significant relationships between two hygienic responses (VSH activity measured as percent change in infestation and the actual brood removal of Varroa-infested donor comb) and two measurements of mite fall (trapped old mites/trapped mites or O/T and trapped young mites/trapped mites or Y/T). However, these relationships were only observed in RHB colonies. In addition, the RHB colonies that displayed the highest levels of hygiene (RHB-HH) also groomed longer in response to the presence of a V. destructor mite based on individual bee assays. The positive regressions between the two hygienic measurements and O/T and their negative regressions with Y/T suggest that the removal of infested brood prevented successful mite reproduction, ultimately suppressing V. destructor infestations in the RHB colonies. In addition, it is demonstrated that RHB resistance to V. destructor rests on both an increased hygienic response and the removal of phoretic mites, released by hygienic behaviour, through grooming. Both resistance traits are reflected in the O/T and Y/T ratios found in trapped mites from RHB colonies. None of the measurements involving mite injuries were associated with any measurements of hygiene and colony infestations.     

Taxonomy and phylogeny of <Emphasis Type="Italic">Cryptocoryneum</Emphasis> (Pleosporales,Dothideomycetes)

Species of Cryptocoryneum were taxonomically reassessed on the basis of morphological observations and the results of molecular phylogenetic analysis. Eighteen isolates of Cryptocoryneum species, namely two strains from Africa, three from Europe, and 13 from Japan, were phylogenetically analysed using sequences of nuclear rDNA internal transcribed spacers (ITS) and the partial sequence of the translation elongation factor 1α gene (TEF1). The phylogenetic analysis indicated that Cryptocoryneum species formed a monophyletic clade and were closely related to Lophiotrema (Lophiotremataceae) and Aquasubmersa (incertae sedis) in the Pleosporales (Dothideomycetes). We examined holotype specimens of C. fasciculatum, C. hysterioides, and Torula uniformis and concluded that these species are conspecific, with C. hysterioides having priority. Although C. hysterioides has long been regarded as a synonym of C. condensatum, we consider C. hysterioides to be a distinct species within the genus. We found several cryptic species that were morphologically similar to C. condensatum sensu lato, but that could be separated on the basis of conidial size and the number of conidial arms and conidial septa, characters that seem to be informative for species delimitation within Cryptocoryneum. A total of seven new species, namely C. akitaense, C. brevicondensatum, C. congregatum, C. japonicum, C. longicondensatum, C. paracondensatum, and C. pseudorilstonei, are described and illustrated. A key to species accepted in Cryptocoryneum is provided.     

Higher phenotypic plasticity does not confer higher salt resistance to <Emphasis Type="Italic">Robinia pseudoacacia</Emphasis> than <Emphasis Type="Italic">Amorpha fruticosa</Emphasis>

A greenhouse experiment was conducted in which two leguminous species commonly used in the Yellow River Delta for vegetation restoration, Robinia pseudoacacia and Amorpha fruticosa, were subjected to five salt treatments: 0, 50, 100, 150, and 200 mmol L^?1. We aimed to determine which of the two species would be better suited for growth in a saline environment, and whether the acclimation capacity to salinity resulted from an inherently higher phenotypic plasticity. The results showed that salinity affected most growth and biomass parameters but had no effects on most leaf traits and physiological parameters of the two species. Height, relative growth rate of crown area, root biomass, and leaf mass ratio of R. pseudoacacia were reduced by higher salinity, while A. fruticosa was not affected. Chlorophyll a-to-chlorophyll b ratio and total antioxidative capacity of A. fruticosa increased with higher salinity, whereas those of R. pseudoacacia remained unchanged. Root mass ratio and vitamin C concentration of both species were not affected by salinity, whereas vitamin C concentration of A. fruticosa was higher than that of R. pseudoacacia. The root-to-shoot ratio of A. fruticosa was higher than that of R. pseudoacacia in most salt treatments. Of all leaf traits, only leaf area differed between treatments. R. pseudoacacia generally exhibited a greater plasticity than A. fruticosa in response to salinity, but A. fruticosa was more resistant to the higher salinities than R. pseudoacacia, and was thus a better candidate for vegetation restoration in saline areas.     

More than royal food - <Emphasis Type="Italic">Major royal jelly protein</Emphasis> genes in sexuals and workers of the honeybee <Emphasis Type="Italic">Apis mellifera</Emphasis>

Background

In the honeybee Apis mellifera, female larvae destined to become a queen are fed with royal jelly, a secretion of the hypopharyngeal glands of young nurse bees that rear the brood. The protein moiety of royal jelly comprises mostly major royal jelly proteins (MRJPs) of which the coding genes (mrjp1-9) have been identified on chromosome 11 in the honeybee’s genome.

Results

We determined the expression of mrjp1-9 among the honeybee worker caste (nurses, foragers) and the sexuals (queens (unmated, mated) and drones) in various body parts (head, thorax, abdomen). Specific mrjp expression was not only found in brood rearing nurse bees, but also in foragers and the sexuals.

Conclusions

The expression of mrjp1 to 7 is characteristic for the heads of worker bees, with an elevated expression of mrjp1-4 and 7 in nurse bees compared to foragers. Mrjp5 and 6 were higher in foragers compared to nurses suggesting functions in addition to those of brood food proteins. Furthermore, the expression of mrjp9 was high in the heads, thoraces and abdomen of almost all female bees, suggesting a function irrespective of body section. This completely different expression profile suggests mrjp9 to code for the most ancestral major royal jelly protein of the honeybee.

     

Thermal tolerance of potential <Emphasis Type="Italic">Trichogramma</Emphasis> strains for mass-production and paddy field release in the Greater Mekong Subregion

In order to identify suitable Trichogramma strains for mass production and successful control of key lepidopteran pests in paddy fields in the Greater Mekong Subregion, the effects of high temperatures on wasp life history traits were compared among three strains of Trichogramma chilonis Ishii and two strains of Trichogramma ostriniae Pang et Chen, collected from paddy fields in the region. At a rearing temperature of 25 °C, life history traits differed significantly among the five strains tested and the three T. chilonis strains and a T. ostriniae strain were of high performance. When female wasps were exposed to higher temperatures commonly encountered in the region, negative effects were observed on key life history parameters of adult females and their offspring at 34 °C, which became even more serious at 37 °C. In particular, the two T. ostriniae strains were not able to successfully develop to adulthood at all at 37 °C while for the T. chilonis strains adult emergence was significantly reduced. In addition, the emerged offspring females lived only around one day and no parasitism was observed. When the three T. chilonis strains were exposed to 37 °C for 4 to 12 h at prepupal and pupal stages, reflecting heat shocks that the released Trichogramma may experience in the field, adult emergence was significantly reduced after an exposure time of 12 h. In summary, the three T. chilonis strains show a relatively high potential for incorporation in a biological control program in the target region. Our results also highlight that tests at both rearing and field temperatures are necessary in selection of potential Trichogramma strains for an inundative release program where there is significant difference between rearing and field temperatures.     

Stable,fertile somatic hybrids between <Emphasis Type="Italic">Sinapis alba</Emphasis> and <Emphasis Type="Italic">Brassica juncea</Emphasis> show resistance to <Emphasis Type="Italic">Alternaria brassicae</Emphasis> and heat stress

Wild relatives of Brassica are a rich reservoir of genes that are invaluable for the improvement of cultivated species. Sinapis alba is a close relative of crop Brassicas that possesses several desirable traits such as tolerance to Alternaria black spot disease, heat stress, insect pests and nematodes. This study is aimed at developing and characterizing hybrids between Brassica juncea and S. alba with the ultimate goal of transferring genes for tolerance to Alternaria brassicae and heat stress, the traits that are lacking in cultivated Brassica. We generated three hybrids between B. juncea and S. alba through protoplast fusion. The hybridity was confirmed through cytology and molecular markers. While two of the hybrids were symmetric, the third one was asymmetric and had greater resemblance to B. juncea. Hybrids showed some characteristic features of the parents and were fully male and female fertile and also set seeds upon back crossing with the parent species. In vitro leaf assay and field inoculation studies revealed that the hybrids are highly resistant to A. brassicae. Besides, hybrids set seeds at temperature of >?38 °C when parents failed to produce seeds indicating that hybrids possess heat tolerance. These stable hybrids provide a reliable genetic resource for transfer of genes from S. alba into cultivated Brassica species.     

Phylogeny of the Neotropical sages (<Emphasis Type="Italic">Salvia</Emphasis> subg. <Emphasis Type="Italic">Calosphace</Emphasis>; Lamiaceae) and insights into pollinator and area shifts

Salvia subg. Calosphace (Lamiaceae, Lamiales) is a highly diverse clade endemic to the New World. The phylogenetic relationships of Calosphace have been previously investigated using DNA sequences of nuclear ITS region and plastid psbA–trnH intergenic spacer, but the resulting trees lack resolution and support for many clades. The present paper reassesses the phylogenetic relationships of subgenus Calosphace, including a broader taxon sampling, with a special focus on representing previously unsampled sections, and using an additional plastid marker (trnL–trnF region). Our results show increased resolution and overall patterns of support, recovering ten main clades. Within core Calosphace, the most inclusive of these main clades, 17 new subclades were identified. Of the 42 sections for which more than one species was analysed, only 12 are monophyletic. Our biogeographical analysis identified at least twelve migrations to South America from Mexican and Central American lineages, in agreement with previous suggestions of multiple origins of South American Calosphace diversity. This analysis also confirmed a colonization of the Antilles by Andean lineages. The reconstruction of ancestral states of pollination syndromes showed multiple shifts to ornithophily from melittophily and one reversal to the latter.     

Genetic drift and uniform selection shape evolution of most traits in <Emphasis Type="Italic">Eugenia dysenterica</Emphasis> DC. (Myrtaceae)

Knowing how microevolutionary processes, such as genetic drift and natural selection, shape variation in adaptive traits is strategic for conservation measures. One way to estimate local adaptation is to compare divergences in quantitative traits (Q_ST) and neutral loci (F_ST). Therefore, we have assessed the pattern of phenotypic and molecular genetic divergence among natural subpopulations of the fruit tree Eugenia dysenterica DC. A provenance and progeny test was performed to assess the quantitative traits of the subpopulations collected in a wide distribution area of the species in the Brazilian Cerrado. The sampled environments are in a biodiversity hotspot with heterogeneous soil and climate conditions. By associating quantitative trait variation in initial seedling development with neutral microsatellite marker variation, we tested the local adaptation of the traits by the Q_ST–F_ST contrast. Genetic drift was prevalent in the phenotypic differentiation among the subpopulations, although the traits seedling emergence time and root green mass, which are relevant for adaptation to the Cerrado climate, showed signs of uniform selection. Our results suggest that E. dysenterica has a spatial genetic structure divided into two large groups, separated by a line that divides the Cerrado biome in a southwestern to northeastern direction. This structure must be taken into account for managing E. dysenterica genetic resources both for conservation and breeding purposes.     

Clinical relevance of infections with zoonotic and human oral species of <Emphasis Type="Italic">Campylobacter</Emphasis>

Genus Campylobacter has been recognized as a causative bacterial agent of animal and human diseases. Human Campylobacter infections have caused more concern. Campylobacters can be classified into two groups in terms of their original host: zoonotic and human oral species. The major zoonotic species are Campylobacter jejuni and Campylobacter coli, which mostly reside in the intestines of avian species and are transmitted to humans via consumption of contaminated poultry products, thus causing human gastroenteritis and other diseases as sequelae. The other campylobacters, human oral species, include C. concisus, C. showae, C. gracilis, C. ureolyticus, C. curvus, and C. rectus. These species are isolated from the oral cavity, natural colonization site, but have potential clinical relevance in the periodontal region to varying extent. Two species, C. jejuni and C. coli, are believed to be mainly associated with intestinal diseases, but recent studies suggested that oral Campylobacter species also play a significant role in intestinal diseases. This review offers an outline of the two Campylobacter groups (zoonotic and human oral), their virulence traits, and the associated illnesses including gastroenteritis.     

Multiple plant traits influence community composition of insect herbivores: a comparison of two understorey shrubs

Structural and nutritional plant traits influence the ability of insect herbivores to locate, consume and persist on their hosts yet it is uncommon for ecologists to consider how multiple plant traits influence insect community composition. We sampled herbivorous insects on two understorey shrub species common to eucalypt forests of south-eastern Australia, namely Cassinia arcuata (Asteraceae) and Daviesia ulicifolia (Fabaceae). Regression analyses were used to assess the relative influence of plant structure (canopy volume), nutritional quality (macronutrients and total phenolics) and plant productivity (leaf litter) on insect abundance and species richness. Total N content of D. ulicifolia was significantly higher than C. arcuata, while the concentrations of P, K, Ca and Mg were higher in C. arcuata. Total phenolics and leaf litter were significantly lower in D. ulicifolia compared to C. arcuata. Insect composition was similar between the two shrubs but C. arcuata supported greater abundances. Canopy volume and the macronutrients P and Ca were important predictors of insect abundance on C. arcuata, whereas canopy volume alone, but neither plant productivity nor macronutrients, influenced the abundance of insects on D. ulicifolia. Ca was an important predictor of insect species richness on C. arcuata and P was an important predictor on D. ulicifolia. By quantifying a range of plant traits, we have provided an understanding of factors likely to influence the composition of herbivorous insects inhabiting these two shrubs. Traits including leaf architecture, foliar morphology and volatile terpenoids may yet explain the greater number of insects on C. arcuata since they influence the availability of microhabitats and apparency of host plants.     

Heat and hypoxia give a global invader, <Emphasis Type="Italic">Gambusia holbrooki,</Emphasis> the edge over a threatened endemic fish on Australian floodplains

Deciphering the mechanisms by which climate change interacts with invasive species to affect biodiversity is a major challenge of global change biology. We conducted experiments to determine whether the global invader, Gambusia holbrooki, was more resistant to high water temperature (heat) and low dissolved oxygen (hypoxia) than a threatened native fish, Nannoperca australis. Metabolic experiments conducted at 25 and 29 °C showed that G. holbrooki had at least four times the capacity for metabolic depression during hypoxia than N. australis. An increase in environmental temperature from 25 to 29 °C had no significant impact on the critical oxygen tension, P _crit, of G. holbrooki, but significantly and strongly increased P _crit of N. australis. Gambusia holbrooki also had a lower Q ₁₀ of standard metabolic rate than N. australis. Our results indicate that G. holbrooki have physiological traits conferring greater resistance to hypoxia than N. australis, and as temperature increases, the resistance of N. australis to hypoxia was more eroded than that of G. holbrooki. Intensive monitoring of the temperature and dissolved oxygen dynamics of wetlands showed that contemporary heat waves are already causing conditions that might give G. holbrooki the edge over N. australis on Australian floodplains. Our study adds weight to recent anecdotal reports of drought and heat waves causing localised extinction of N. australis, but the proliferation of G. holbrooki.