Development of parasitic <Emphasis Type="Italic">Maculinea teleius</Emphasis> (Lepidoptera,Lycaenidae) larvae in laboratory nests of four <Emphasis Type="Italic">Myrmica</Emphasis> ant host species

Maculinea butterflies are social parasites of Myrmica ants. Methods to study the strength of host ant specificity in the Maculinea–Myrmica association include research on chemical and acoustic mimicry as well as experiments on ant adoption and rearing behaviour of Maculinea larvae. Here we present results of laboratory experiments on adoption, survival, development and integration of M. teleius larvae within the nests of different Myrmica host species, with the objective of quantifying the degree of specialization of this Maculinea species. In the laboratory, a total of 94 nests of four Myrmica species: M. scabrinodis, M. rubra, M. ruginodis and M. rugulosa were used. Nests of M. rubra and M. rugulosa adopted M. teleius larvae more readily and quickly than M. ruginodis colonies. No significant differences were found in the survival rates of M. teleius larvae reared by different ant species. Early larval growth of M. teleius larvae differed slightly among nests of four Myrmica host species. Larvae reared by colonies of M. rugulosa which were the heaviest at the beginning of larval development had the lowest mean larval body mass after 18 weeks compared to those reared by other Myrmica species. None of the M. teleius larvae was carried by M. scabrinodis or M. rubra workers after ant nests were destroyed, which suggests a lack of integration with host colonies. Results indicate that Myrmica species coming from the same site differ in their ability to adopt and rear M. teleius larvae but there was no obvious adaptation of this butterfly species to one of the host ant species. This may explain why, under natural conditions, all four ants can be used as hosts of this butterfly species. Slight advantages of particular Myrmica species as hosts at certain points in butterfly larval development can be explained by the ant species biology and colony structure rather than by specialization of M. teleius.     

Fen meadows on the move for the conservation of <Emphasis Type="Italic">Maculinea (Phengaris) teleius</Emphasis> butterflies

In the Netherlands, a single population of the obligate myrmecophilic butterfly Maculinea (Phengaris) teleius has survived on only 3 ha of habitat for more than 25 years, whereas at least 40 ha of habitat are thought to be required for a sustainable metapopulation. Therefore, 170 ha of farmland is being restored to wet meadows within a LIFE?+?project by large-scale soil excavation and hay inoculation. For successful restoration, the habitat requirements of the butterfly, with Sanguisorba officinalis as host plant and its particular life cycle as parasite of the ant species Myrmica scabrinodis, have to be taken into account. We tested whether colonization of nests of this ant species in the restoration areas is facilitated by translocation of sods collected from fen meadows. We divided 54 sods, each sized 1 m², randomly over six patches and measured vegetation development and ant presence in the sods and surrounding control plots for 2 years. In the first summer, significantly more Myrmica ants were found in the transplanted sods in comparison to the surrounding area. Herb cover had a significant positive effect on Myrmica ant presence while it did not affect the presence of the pioneer ant species Lasius niger. In the second year, Myrmica ants were found in the surrounding control plots as well. This study contributes to the knowledge-base required for the design of restoration projects aimed at expanding the habitat of the critically endangered butterfly Maculinea (Phengaris) teleius.     

All natural habitat edges matter equally for endangered <Emphasis Type="Italic">Maculinea</Emphasis> butterflies

An obvious consequence of habitat fragmentation is an increasing role of habitat edges for species survival. Recently it has been suggested that the endangered butterfly Maculinea nausithous prefers forested edges of its meadow habitats. However, the prevalence of forests in the study area used for this analysis makes it impossible to distinguish whether the effect detected is a genuine preference for forest edges or a preference for any natural patch edges as opposed to patch interiors. We investigated habitat selection by Maculinea nausithous and Maculinea teleius occurring sympatrically at five habitat patches surrounded by mosaic landscape. Butterfly capture positions were marked with GPS and subsequently analysed with GIS software. Both species avoided the interiors of their patches and concentrated in the edge zone, but these preferences were visible only at three larger patches exceeding 1 ha in area. Among different types of edges those bordering densely built-up areas were avoided, whereas all natural edges (adjacent to forests, reeds or grasslands) were similarly used. We hypothesise that preferences towards natural patch edges, regardless of their type, can be explained by the spatial interactions between Maculinea butterflies and Myrmica ants they parasitise. Patch surroundings constitute refuge space for the ants, and hence their densities may be expected to be higher near patch edges. Our findings indicate the importance of patch surroundings for the persistence of Maculinea populations. Regretfully, current legal framework makes it difficult to protect patch surroundings, where neither priority species nor their habitats occur.     

Distribution and habitats of <Emphasis Type="Italic">Phengaris</Emphasis> (<Emphasis Type="Italic">Maculinea</Emphasis>) butterflies and population ecology of <Emphasis Type="Italic">Phengaris</Emphasis><Emphasis Type="Italic">teleius</Emphasis> in China

Many species of the butterfly genus Phengaris are regarded as endangered in many parts of their distribution. Several species are also widely distributed across northern China. Due to land use change and overgrazing, their habitats are declining and many patches have been lost. This paper investigates the distribution and habitats of the Chinese Phengaris species (of the subgenus Maculinea). Shrub-grassland near forests seem the most frequent habitat for Phengaris, while flat open grasslands are mostly over-grazed and thus survival for Phengaris butterflies there seems difficult. Throughout Europe, P. teleius is an endangered species, while there is still no information on its status in China. To improve the knowledge on the population ecology of P. teleius, its population structure, adult behaviour and movement were studied through mark–release–recapture methods in the Qinling Mountains of Taibai County. Eight grassland patches which were potentially suitable were found in the area in 2013. In total, 480 individuals (274 females) were marked, resulting in an overall recapture rate of 16 %. The average daily population size was 44 butterflies (±23 SD) during the adult flight period. Sixty-seven percent of the females and 38 % of the males moved less than 50 m, and 17 % of recaptured females and 38 % of males moved more than 200 m. The mean movement distance was 107 ± 177 m for males and 182 ± 122 m for females. The majority of the recaptures (86 %) were made within the patches, only a few individuals (14 %) moved between patches. Due to human disturbance and destruction, all of the eight potentially suitable patches are becoming smaller and increasingly isolated, thus these populations of P. teleius may face an increasing risk of extinction, which may well be a tip of the iceberg of habitat loss and fragmentation of P. teleius in Taibai County and possibly beyond. Hence we hope our initial study of P. teleius could have positive impacts on the conservation of Phengaris butterflies in China.     

Effects of Host Interspecific Interaction in the <Emphasis Type="Italic">Maculinea</Emphasis>–<Emphasis Type="Italic">Myrmica</Emphasis> Parasite–Host System

A model of interspecific host competition in a system with one parasite (butterfly—Maculinea) and multiple potential hosts (ants—Myrmica) is presented. Results indicate that host interspecific competition increases the occurrence of multiple host behaviour in Maculinea natural populations but decreases the ability of the parasite populations to adapt to the most abundant host species. These qualitative predictions were compared with data on host specificity, with good agreement. Analysis of the data also indicates that Maculinea teleius and Maculinea arion respond differently to changes in relative host abundances. Maculinea teleius shows a larger fraction of sites where it displays multiple host behaviour and a larger fraction of sites where the niches of the hosts overlap. In some instances, Maculinea teleius is adapted to Myrmica hosts that are present in lower frequencies. Maculinea arion is locally more host-specific and occurs at sites where host interspecific competition is unlikely and is more frequently adapted to the most abundant host species.     

Conservation implications of source-sink dynamics within populations of endangered <Emphasis Type="Italic">Maculinea</Emphasis> butterflies

Conservation programmes are often based on snapshot information on animal abundance. However, land fragments with high numbers of individuals do not necessarily represent their natal areas, which are crucial for species persistence. A classic example of the above principle are source-sink systems, in which excess individuals emigrate from source areas during their lifetime and gather in sink areas. We demonstrated the existence of source-sink dynamics in two species of endangered Maculinea (=Phengaris) butterflies. Sympatrically occurring M. nausithous and M. teleius were investigated with mark-recapture sampling during the entire flight period. In the first half of the season a great majority of butterflies were captured within the relatively small central part of the site, while later their numbers became similar between the site centre and its peripheries. The analysis of movements indicated that most individuals captured in the peripheral zone eclosed in the central zone. Moreover, the timing of the sharp increase in movements from the site centre to its peripheries corresponded well with the period when the number of eggs laid in the former area reached carrying capacity, defined by the number of the Sanguisorba officinalis foodplant flowerheads available for oviposition. Within the peripheral zone the foodplant availability greatly exceeded the egg load, but in contrast the abundance of host ants (i.e. the other essential resource) was low, which presumably results in low Maculinea larval survival there. Our findings imply that setting conservation priorities over different land fragments should take into account dispersion of individuals among them.     

A mowing experiment to evaluate the influence of management on the activity of host ants of <Emphasis Type="Italic">Maculinea</Emphasis> butterflies

Maculinea butterflies obligatory parasitize certain species of Myrmica ants. Thus, the presence of the host ant species is a limiting factor for the survival of a Maculinea population. Here, we analyse the influence of vegetation structure and ground temperature on ant diversity and abundance on Maculinea habitats, with the final aim of identifying the environmental variables determining patterns of variation in species composition in order to recommend a mowing regime that will promote our three target species: Maculinea teleius, M. nausithous and M. alcon. Experimental plots with different mowing regimes were established at eight sites in South-Eastern Germany, a region which still contains a number of relatively large, stable populations of these threatened butterfly species. Among the seven different ant species recorded, four belong to the genus Myrmica (M. scabrinodis, M. rubra, M. ruginodis and M. vandeli). Among these, M. scabrinodis results most abundant at all sites. In a CCA analysis of environmental variables recorded at the studied plots, ant species diversity appears largely determined by litter cover, mean temperature, and mean grass cover. Mowing once a year, in the second half of September, after the larvae have left their host plants, enhances the abundance of Myrmica ants in the meadows, and would be the best management compromise for all three species.     

Reduced ant defenses in <Emphasis Type="Italic">Macaranga</Emphasis> myrmecophytes (Euphorbiaceae) infested with a winged phasmid <Emphasis Type="Italic">Orthomeria cuprinus</Emphasis>

Macaranga is a tree genus that includes many species of myrmecophytes, which are plants that harbor ant colonies within hollow structures known as domatia. The symbiotic ants (plant–ants) protect their host plants against herbivores; this defense mechanism is called ‘ant defense’. A Bornean phasmid species Orthomeria cuprinus feeds on two myrmecophytic Macaranga species, Macaranga beccariana and Macaranga hypoleuca, which are obligately associated with Crematogaster ant species. The phasmids elude the ant defense using specialized behavior. However, the mechanisms used by the phasmid to overcome ant defenses have been insufficiently elucidated. We hypothesized that O. cuprinus only feeds on individual plants with weakened ant defenses. To test the hypothesis, we compared the ant defense intensity in phasmid-infested and non-infested M. beccariana trees. The number of plant–ants on the plant surface, the ratio of plant–ant biomass to tree biomass, and the aggressiveness of plant–ants towards experimentally introduced herbivores were significantly lower on the phasmid-infested trees than on the non-infested trees. The phasmid nymphs experimentally introduced into non-infested trees, compared with those experimentally introduced into phasmid-infested trees, were more active on the plant surface, avoiding the plant–ants. These results support the hypothesis and suggest that ant defenses on non-infested trees effectively prevent the phasmids from remaining on the plants. Thus, we suggest that O. cuprinus feeds only on the individual M. beccariana trees having decreased ant defenses, although the factors that reduce the intensity of the ant defenses remain unclear.     

Adaptive loss of color polymorphism and character displacements in sympatric <Emphasis Type="Italic">Mnais</Emphasis> damselflies

A geographical survey of two Mnais damselfly species in the Kinki area of Japan showed evidence for character displacements when the two species were found in sympatry. Mnais costalis, a species that has polymorphic male mating types of orange-winged territorial and clear-winged non-territorial morphs (hereafter abbreviated to orange and clear morphs respectively) in allopatry often shifted to having monomorphic orange morphs in sympatry. The mean body size of orange morphs was consistently larger than that of clear morph in allopatry. The mean body size of the sympatric orange morphs was even larger than that of allopatric orange morphs. By contrast, Mnais pruinosa, a species that also has two morphs of large orange and small clear morphs in allopatry, shifted to having monomorphic clear morphs in sympatry. The mean body size of the sympatric clear morphs was smaller than that of allopatric clear morphs. Divergence was also detected in the preference for habitat insolation conditions between sympatric Mnais damselflies. Both species in allopatric regions prefer half-light forest habitats, while in sympatric regions they showed diversified habitat preference: M. costalis preferred sunny habitats while M. pruinosa preferred shady habitats. Multiple character displacements in signal traits and habitat preference emerged in heterogeneous forest light environments are likely to have synergistic effects on the reproductive isolation of the two species.     

Comparison of trophic function between the globally invasive crayfishes <Emphasis Type="Italic">Pacifastacus leniusculus</Emphasis> and <Emphasis Type="Italic">Procambarus clarkii</Emphasis>

Impacts of invasive species may manifest most strongly if these organisms are highly distinct functionally from the native species they often replace. Yet, should we expect functional differences between native and invasive species of generalist organisms like freshwater crayfish? Some existing evidence has pointed to native and invasive crayfish species as ecologically equivalent. We contribute to this literature by comparing the trophic niches of the globally invasive crayfishes Pacifastacus leniusculus and Procambarus clarkii, by applying carbon and nitrogen stable isotope analyses to replicated allopatric (alone) and sympatric (together) lake populations in western Washington State, USA, where P. clarkii has been recently introduced and P. leniusculus is presumed native. Our study corrected for potential inherent differences in lake food webs as a consequence of lake abiotic or biotic characteristics using random effects in linear mixed effects models. We found that although overall trophic niche size or area of these species was not significantly different, P. leniusculus was significantly higher in trophic position than P. clarkii when also accounting for the effects of body size, sex, and lakes as random effects. This pattern of increased trophic position of P. leniusculus over P. clarkii was conserved over time in one sympatric lake for which we had data over multiple years. Cumulatively, our findings point to trophic differences between the globally cosmopolitan crayfishes P. leniusculus and P. clarkii, particularly when accounting for the ways that ecosystem context can affect food web structure of communities and the trophic resources available to these consumers.     

The importance of resource distribution: spatial co-occurrence of host plants and host ants coincides with increased egg densities of the Dusky Large Blue <Emphasis Type="Italic">Maculinea nausithous</Emphasis> (Lepidoptera: Lycaenidae)

The occurrence of the Dusky Large Blue Butterfly (Maculinea nausithous) critically depends on the availability of two key resources: the Great Burnet (Sanguisorba officinalis) as primary nectar source for adults, for egg laying and early larval development, and the host ant Myrmica rubra as the food of late instar larvae. Thus, their distributions are key parameters shaping habitat suitability, and we expected that overlapping of both resources would have a strong impact on the size of local M. nausithous populations. Their egg density may be affected (a) by the fraction of host plants per site located within My. rubra activity ranges at the patch scale, or (b) by the availability of host plants with host ants in close range at the local scale, due to the potential ability of butterfly females to detect their host ants. To test the above hypothesis, we recorded spatial distribution patterns of host plants and host ants on 29 study sites in south-western Germany and related them to egg density data of M. nausithous. We found a positive relationship between co-occurence of host plant and host ant and M. nausithous egg density at the patch scale, whereas no correlation was found at the local scale. Thus, focal populations are strongly limited by the abundance of host plants, covered with My. rubra activity, as ant-mediated oviposition could not be proved. Our results underline the importance of resource distribution; the understanding of its impacts may provide useful insights into how M. nausithous habitats can be managed in order increase their carrying capacity.     

Yeast communities of <Emphasis Type="Italic">Formica aquilonia</Emphasis> colonies

Yeast abundance and species diversity in the colonies of Formica aquilonia ants in birch–pine grass forest near Novosibirsk, Russia, were studied. The average yeast number in the anthill material was 10³–10⁴ CFU/g, reaching 10⁵ CFU/g in the hatching chambers. Typical litter species (Trichosporon moniliiforme and Cystofilobasidium capitatum) were predominant in soil and litter around the anthills. Apart from these species, ascomycete species of the family Debaryomycetaceae, Debaryomyces hansenii, and Schwanniomyces vanrijiae were predominant in the anthill material. Yeast population of the ant’ bodies consisted exclusively of the members of the last two species. Thus, highly specific yeast communities formed in the colonies of Formica aquilonia ants differ from the communities of surrounding soil. These differences are caused by environment-forming activity of the ants.     

Parasitism rates and parasitoid complexes of the wheat midges, <Emphasis Type="Italic">Sitodiplosis mosellana</Emphasis>, <Emphasis Type="Italic">Contarinia tritici</Emphasis> and <Emphasis Type="Italic">Haplodiplosis marginata</Emphasis>

Three species of cecidomyiid midges (Diptera: Cecidomyiidae), whose larvae overwinter in the soil, can cause significant yield losses on wheat in Europe: the orange wheat blossom midge, Sitodiplosis mosellana (Géhin), the yellow wheat blossom midge, Contarinia tritici (Kirby), and the saddle gall midge, Haplodiplosis marginata (von Roser). The biological control of wheat midges by their parasitoids can contribute to reduce the midge populations. Soil samples were collected in several fields in Belgium in 2012–2014 in order to characterize the parasitism rates and parasitoid complexes in overwintering larvae. The parasitism rates varied greatly between the sampled fields: 3–100, 0–100 and 2% for S. mosellana, H. marginata and C. tritici, respectively. The parasitism rate was not related to the larval density of wheat midge. The three wheat midges have totally distinct parasitoid complexes in Belgium. Eight species (Hymenoptera: Pteromalidae and Platygastridae) were found as parasitoid of S. mosellana: Macroglenes penetrans (Kirby), Amblypasis tritici (Walker), Euxestonotus error (Fitch), Euxestonutus sp. Fouts, Leptacis sp. Foerster, Platygaster gracilipes (Huggert), Platygaster nisus Walker, and Platygaster tuberosula (Kieffer). According to their abundance, M. penetrans, E. error and P. tuberosula appeared as the main parasitoids of S. mosellana in Belgium. For the two other wheat midges, only one species of the family Platygastridae was found for each midge: Platygaster equestris (Spittler) for H. marginata and Synopeas myles (Walker) for C. tritici.     

Phylogenetic assessment and taxonomic revision of <Emphasis Type="Italic">Mariannaea</Emphasis>

Four new species of Mariannaea were described in this paper, namely M. chlamydospora, M. cinerea, M. fusiformis, and M. lignicola. Mariannaea chlamydospora is characterized by its cream-colored, zonate colonies on PDA, smooth conidiophores, fusiform conidia, and abundant chlamydospores. Mariannaea cinerea forms grey colonies and ellipsoidal to subglobose conidia. Mariannaea fusiformis forms purple colonies and fusiform to subglobose conidia. Mariannaea lignicola has brown conidiophores and broad hyphae. The molecular phylogeny was inferred using ITS, LSU, and TUB-2 loci. The type species of Mariannaea (M. elegans) is epitypified. The variety M. elegans var. punicea is raised to species rank. Mariannaea clavispora is excluded from Mariannaea because of its cylindrical phialides, straight conidial chains and deviating phylogenetic affinity. Mariannaea nipponica did not fit well the generic concept of Mariannaea based on their morphological characters, and its generic placement remains uncertain. A key to the currently accepted 15 species of Mariannaea is provided.     

Geographical variation of skull characters in pikas (<Emphasis Type="Italic">Ochotona</Emphasis>, Lagomorpha) of the<Emphasis Type="Italic">alpina-hyperborea</Emphasis> group

A multivariate analysis of 11 skull measurements, along with evaluation of the shape of maxill-premaxill suture at palatine foramina, was carried out in pikas of thealpina-hyperborea group. The study provided rational for recognition of three distinct species in this group:Ochotona alpina (Pallas, 1773),O. hyperborea (Pallas, 1811), andO. turuchanensis Naumov, 1934.O. turuchanensis is a species from central Siberia differing fromO. hyperborea in the chromosome number and type of palatine foramina and fromO. alpina in size of the skull. This species is allopatric withO. alpina and partly sympatric withO. hyperborea. The subspeciessvatoshi is reportedly allocated toO. hyperborea. The taxonomic status ofmantchurica (now allocated tohyperborea) and scorodumovi (treated at present as an isolated subspecies of O. alpina) needs careful investigation.     

The endosymbiont <Emphasis Type="Italic">Wolbachia</Emphasis> in Eurasian populations of <Emphasis Type="Italic">Drosophila melanogaster</Emphasis>

The endosymbiotic α-proteobacteria Wolbachia is widely spread among arthropods and Filariidae nematodes. This bacterium is transmitted vertically via a transovarian route. Wolbachia is a cause of several reproductive abnormalities in the host species. We analyzed the isofemale lines created using flies collected from Drosophila melanogaster natural populations for infection with the endosymbiont Wolbachia. Wolbachia were genotyped according to five variable markers: the presence of insertion sequence IS5 in two loci, the copy number of two minisatellite repeats, and an inversion. Overall, 665 isofemale lines isolated from the populations of D. melanogaster from Ukraine, Belarus, Moldova, Caucasus, Central Asia, Ural, Udmurtia, Altai, West and East Siberia, and Far East in 1974 through 2005 were used in the work. The samples from Ukrainian, Altaian, and Middle Asian populations were largest. The infection rate of D. melanogaster populations from Middle Asia, Altaian, and Eastern Europe (Ukraine, Moldavia, and Belarus) with Wolbachia amounted to 64, 56, and 39%, respectively. The D. melanogaster population from the Caucasus displayed heterogeneity in the genotypes of this cytoplasmic infection. The Wolbachia genotype wMel, detected in all the populations studied, was the most abundant. The genotype wMelCS2 was always present in the populations from Middle Asia and Altai and was among the rare variants in the D. melanogaster populations from the Eastern Europe. Single instances of the Wolbachia genotype wMelCS occurred in a few flies from the Central Asian and Altai populations, but was not found this genotype in the other regions.     

<Emphasis Type="Italic">Quinua</Emphasis> and Relatives (<Emphasis Type="Italic">Chenopodium</Emphasis> sect.<Emphasis Type="Italic">Chenopodium</Emphasis> subsect.<Emphasis Type="Italic">Celluloid</Emphasis>)

Traditionally viewed as an Andean grain crop,Chenopodium quinoa Willd. includes domesticated populations that are not Andean, and Andean populations that are not domesticated. Comparative analysis of leaf morphology and allozyme frequencies have demonstrated that Andean populations, both domesticated(quinua) and free-living(ajara), represent an exceptionally homogeneous unit that is well differentiated from allied domesticates of coastal Chile(quingua) and freeliving populations of the Argentine lowlands(C. hircinum). This pattern of relationships indicates that Andean populations represent a monophyletic crop/weed system that has possibly developed through cyclic differentiation (natural vs. human selection) and introgressive hybridization. Relative levels of variation suggest that this complex originated in the southern Andes, possibly from wild types allied withC. hircinum, with subsequent dispersal north to Colombia and south to the Chilean coast. Coastal populations were apparently isolated from post-dispersal differentiation and homogenization that occurred in the Andes. Other data point toward a center of origin in the northern Andes with secondary centers of genetic diversity subsequently developing in the southern Andes and the plains of Argentina. Comparative linkage of South American taxa, all tetraploid, with North American tetraploids of the subsection will eventually clarify this problem. While the possibility of a direct phyletic connection betweenC. quinoa and the Mexican domesticate(C. berlandieri subsp. nuttalliae,) cannot be excluded, available evidence indicates that the latter represents an autonomous lineage that is associated with the basal tetraploid, C. b. subsp.berlandieri, through var.sinuatum, whereas South American taxa show possible affinities to either var. zschackei or var.berlandieri. An extinct domesticate of eastern North America,C. b. subsp.jonesianum, represents either another instance of independent domestication, possibly from subsp. b. var.zschackei, or a northeastern outlier of subsp.nuttalliae.     

<Emphasis Type="Italic">STAYGREEN</Emphasis> (<Emphasis Type="Italic">CsSGR</Emphasis>) is a candidate for the anthracnose (<Emphasis Type="Italic">Colletotrichum orbiculare</Emphasis>) resistance locus <Emphasis Type="Italic">cla</Emphasis> in Gy14 cucumber

Key message

Map-based cloning identified a candidate gene for resistance to the anthracnose fungal pathogen Colletotrichum orbiculare in cucumber, which reveals a novel function for the highly conserved STAYGREEN family genes for host disease resistance in plants.

Abstract

Colletotrichum orbiculare is a hemibiotrophic fungal pathogen that causes anthracnose disease in cucumber and other cucurbit crops. No host resistance genes against the anthracnose pathogens have been cloned in crop plants. Here, we reported fine mapping and cloning of a resistance gene to the race 1 anthracnose pathogen in cucumber inbred lines Gy14 and WI 2757. Phenotypic and QTL analysis in multiple populations revealed that a single recessive gene, cla, was underlying anthracnose resistance in both lines, but WI2757 carried an additional minor-effect QTL. Fine mapping using 150 Gy14?×?9930 recombinant inbred lines and 1043 F₂ individuals delimited the cla locus into a 32 kb region in cucumber Chromosome 5 with three predicted genes. Multiple lines of evidence suggested that the cucumber STAYGREEN (CsSGR) gene is a candidate for the anthracnose resistance locus. A single nucleotide mutation in the third exon of CsSGR resulted in the substitution of Glutamine in 9930 to Arginine in Gy14 in CsSGR protein which seems responsible for the differential anthracnose inoculation responses between Gy14 and 9930. Quantitative real-time PCR analysis indicated that CsSGR was significantly upregulated upon anthracnose pathogen inoculation in the susceptible 9930, while its expression was much lower in the resistant Gy14. Investigation of allelic diversities in natural cucumber populations revealed that the resistance allele in almost all improved cultivars or breeding lines of the U.S. origin was derived from PI 197087. This work reveals an unknown function for the highly conserved STAYGREEN (SGR) family genes for host disease resistance in plants.

     

qPCR estimates of <Emphasis Type="Italic">Babesia bovis</Emphasis> and <Emphasis Type="Italic">Babesia bigemina</Emphasis> infection levels in beef cattle and <Emphasis Type="Italic">Rhipicephalus microplus</Emphasis> larvae

Babesia spp. are tick-transmitted intraerythrocytic apicomplexan parasites that infect wild and domestic animals. Babesia bovis and B. bigemina are endemic and responsible for enormous economic losses to the livestock industry in most of the Brazilian territory, wherein the tick Rhipicephalus microplus is the unique vector. Better understanding of epidemiology and parasite–host interactions may improve the tools for disease control and genetic management for selection of resistant animals. This study aimed to detect, quantify and measure the correlation between B. bigemina and B. bovis infection levels in bovine blood and into tick, by absolute quantification of hemoparasite DNA using qPCR. Blood bovine samples and larvae pools from 10 engorged R. microplus females were collected from each Canchim heifers (5/8 Charolais?+?3/8 zebu, n?=?36). All evaluated samples were positive for both Babesia species tested. Correlations of B. bovis and B. bigemina levels between cattle and tick host were 0.58 and 0.66, respectively. These high positive correlation coefficients indicate that parasitemia load in the bovine may be dependent on or may determine the parasitemia load in the ticks.     

Comparative analysis of immune responses in Colorado potato beetle larvae during development of mycoses caused by <Emphasis Type="Italic">Metarhizium robertsii</Emphasis>, <Emphasis Type="Italic">M. brunneum</Emphasis>, and <Emphasis Type="Italic">M. pemphigi</Emphasis>

Development of mycoses and progress of humoral and cellular immune responses were compared in larvae of the Colorado potato beetle Leptinotarsa decemlineata infected with entomopathogenic fungi Metarhizium robertsii, M. brunneum and M. pemphigi. The larvae were found to be highly susceptible to the strains of M. robertsii and M. brunneum but weakly responsive to M. pemphigi. The extent of susceptibility to the pathogens was not related to the stimulating effect of epicuticular extracts on fungal growth. Metarhizium pemphigi, which is non-specific to the Colorado potato beetle, did not cause any significant changes in the immune response and did not colonize the hemocoel. When infected with M. robertsii and M. brunneum, the larvae exhibited an increase in hemocyte count during the early stage of mycosis (day 2) followed by a drastic decrease on day 3. The immunocompetent cells, plasmatocytes and granulocytes, exhibited the greatest decrease. Elevated phenoloxidase activity was recorded in the hemolymph and cuticle on days 2 and 3 post-infection. These changes in the immune responses correlated with strain-specific virulence. Thus, the immune response in Colorado potato beetle larvae is an important factor, which determines differences in the development of mycoses caused by different Metarhizium species.