Geographic distribution and molecular diversity of Bartonella infections in moose, Alces alces, in Finland.

Moose, Alces alces (Artiodactyla: Cervidae) in Finland are heavily infested with deer keds, Lipoptena cervi (Diptera: Hippoboschidae). The deer ked, which carries species of the genus Bartonella, has been proposed as a vector for the transmission of bartonellae to animals and humans. Previously, bartonella DNA was found in deer keds as well as in moose blood collected in Finland. We investigated the prevalence and molecular diversity of Bartonella spp. infection from blood samples collected from free-ranging moose. Given that the deer ked is not present in northernmost Finland, we also investigated whether there were geographic differences in the prevalence of bartonella infection in moose. The overall prevalence of bartonella infection was 72.9% (108/148). Geographically, the prevalence was highest in the south (90.6%) and lowest in the north (55.9%). At least two species of bartonellae were identified by multilocus sequence analysis. Based on logistic regression analysis, there was no significant association between bartonella infection and either age or sex; however, moose from outside the deer ked zone were significantly less likely to be infected (P<0.015) than were moose hunted within the deer ked zone.

Evaluación de la preferencia de Liriomyza spp. en genotipos diferentes de garbanzo y efecto del extracto de Melia azedarach L. : resultados preliminares

En Argentina se están desarrollando genotipos de garbanzo (Cicer arietinum L.) para adecuarlos a las distintas zonas de producción. Estos presentan diferentes fenotipos lo que podría afectar las preferencias de oviposición de los insectos herbívoros de hábito minador. Los objetivos de este trabajo fueron: 1) determinar si las hembras del género Liriomyza spp. muestran preferencia por algún genotipo de garbanzo, y 2) evaluar el efecto del extracto de Melia azedarach sobre las líneas de garbanzo que resultaran susceptibles. Se sembraron dos líneas selectas y dos cultivares de C. arietinum que presentan hojas unifoliadas enteras o compuestas, en el Campo Experimental de la Facultad de Ciencias Agropecuarias, Universidad Nacional de Córdoba, en bloques al azar con tres repeticiones. Para analizar la preferencia, mediante censos semanales se evaluó la presencia de las larvas de las moscas en el período julio-septiembre. Los dípteros eligieron de manera significativa los genotipos de hoja entera y grande. Posteriormente, las plantas con hojas minadas de las variedades preferidas fueron sometidas a tratamiento con el extracto botánico. Para ello se marcaron cinco plantas de cada bloque: a 15 se les aplicó extracto (10%) y a las otras 15 agua (control). Se observó que el número de hojas minadas, de pupas y adultos emergidos disminuyeron en los tratamientos con el extracto. Estudios complementarios serán necesarios para poder considerar este compuesto natural en un plan de manejo del herbívoro.

Biología de la psychidosmicra Brethesi Blanchard : enemigo natural del "bicho del cesto" común, Oiketicus Kirbyi Guild

La finalidad de este trabajo fué determinar las especies parásitas e hiperparásitas del "bicho del cesto" común, Oiketicus Kirbyi Guild, en Mendoza, a fin de obtener supervivencia de la que se encuentra en mayor número e intensidad. Como resultado de estas investigaciones se comprobó que el calcídido Psychidosmicra Brethesi Blanchard constituye un eficáz enemigo específico del psíquico, llegándose a la conclusión que debe preservarse dicho material por el método de aislamiento en su época oportuna, permitiendo esto incrementar las poblaciones por dispersión artificial y atenuar la acción del factor hiperparasitismo.

Investigation of knot nests on Ellesmere Island

Knots arrive on Ellesmere Island in late May or early June. At Hazen Camp small flocks were present on 3 June 1966, but the main influx occurred 5 June when many flocks were seen ranging in size from 6 to 60 individuals. The sexes appeared to arrive together, but the manner of pair-formation was not determined. By 7 June pairs were distributed over the tundra with large feeding flocks forming at snowfree wet marshy areas. Most nests were on Dryas-hummocked slopes and tundra, either dry or moist, with some on clay plains and summits in a mixed Dryas and Salix vegetation. A census area of 240 ha supported at least 3 breeding pairs, and possibly 5; the total number of pairs breeding in the Hazen Camp study area was estimated to be about 25 (1.09 pairs/km**2). Egg-laying (4 nests) extended from 15 to 28 June, with 3 of the 4 sets completed between 20 and 23 June. Both sexes incubated, one of the pair more regularly than the other. The song-flight display of the male was performed most frequently during egglaying and incubation. The incubation period of the last egg in one clutch was established as being between 21.5 and 22.4 days. Four nests hatched between 12 and 20 July, and the hatching period of the entire clutch was less than 24 hours. Four of 7 nests (57 %) survived and egg survival (53 %) was low. Families left the nesting area so on after hatching, concentrating at ponds where food was readily available for the young. Both adults attended the young during the pre-fledging period, but the females apparently departed before the young had hedged. Males left once the young could fly and the adult fall migration was complete by early August. Most 01 the young departed belore mid-August. Fall migration is complete by late August or early September. The breeding season appears to be timed to peak load supply for the young. Adult Chironomidae emergence was highest between 3 and 17 July, the period during which most successful nests hatched. The increasing scarcity of adult insects for the young after mid-July was offset by family movements over the tundra and the early departure of half the adult population. Food also seemed to influence the distribution of breeding pairs aver the tundra, restricting them to the general vicinity of marshes, streams, and ponds where food is most available when the young hatch. Territoriality in the Knot appears to be closely associated with the protection of the nest against predators and has at least a local effect in regulating the number of breeding pairs. Plant material was important in the diet of adult Knots throughout the summer and the primary food from the time of arrival until mid-June. After mid-June the percentage of animal matter increased as dipterous insects became available (especially adult Chironomidae), but plant materials continued to constitute a large part of the diet, usually more than 50 %. The food of the young before fledging consisted principally of adult chironomids.

Macroinvertebrate abundance and proportion of trait categories in river biotopes across England and Wales

There is a long tradition of river monitoring using macroinvertebrate communities to assess environmental quality in Europe. A promising alternative is the use of species life-history traits. Both methods, however, have relied on the time-consuming identification of taxa. River biotopes, 1-100 m**2 'habitats' with associated species assemblages, have long been seen as a useful and meaningful way of linking the ecology of macroinvertebrates and river hydro-morphology and can be used to assess hydro-morphological degradation in rivers. Taxonomic differences, however, between different rivers had prevented a general test of this concept until now. The species trait approach may overcome this obstacle across broad geographical areas, using biotopes as the hydro-morphological units which have characteristic species trait assemblages. We collected macroinvertebrate data from 512 discrete patches, comprising 13 river biotopes, from seven rivers in England and Wales. The aim was to test whether river biotopes were better predictors of macroinvertebrate trait profiles than taxonomic composition (genera, families, orders) in rivers, independently of the phylogenetic effects and catchment scale characteristics (i.e. hydrology, geography and land cover). We also tested whether species richness and diversity were better related to biotopes than to rivers. River biotopes explained 40% of the variance in macroinvertebrate trait profiles across the rivers, largely independently of catchment characteristics. There was a strong phylogenetic signature, however. River biotopes were about 50% better at predicting macroinvertebrate trait profiles than taxonomic composition across rivers, no matter which taxonomic resolution was used. River biotopes were better than river identity at explaining the variability in taxonomic richness and diversity (40% and <=10%, respectively). Detailed trait-biotope associations agreed with independent a priori predictions relating trait categories to near river bed flows. Hence, species traits provided a much needed mechanistic understanding and predictive ability across a broad geographical area. We show that integration of the multiple biological trait approach with river biotopes at the interface between ecology and hydro-morphology provides a wealth of new information and potential applications for river science and management.

Selective maintenance of allozyme differences among sympatric host races of the apple maggot fly

Whether phytophagous insects can speciate in sympatry when they shift and adapt to new host plants is a controversial question. One essential requirement for sympatric speciation is that disruptive selection outweighs gene flow between insect populations using different host plants. Empirical support for host-related selection (i.e., fitness trade-offs) is scant, however. Here, we test for host-dependent selection acting on apple (Malus pumila)- and hawthorn (Crataegus spp.)-infesting races of Rhagoletis pomonella (Diptera: Tephritidae). In particular, we examine whether the earlier fruiting phenology of apple trees favors pupae in deeper states of diapause (or with slower metabolisms/development rates) in the apple fly race. By experimentally lengthening the time period preceding winter, we exposed hawthorn race pupae to environmental conditions typically faced by apple flies. This exposure induced a significant genetic response at six allozyme loci in surviving hawthorn fly adults toward allele frequencies found in the apple race. The sensitivity of hawthorn fly pupae to extended periods of warm weather therefore selects against hawthorn flies that infest apples and helps to maintain the genetic integrity of the apple race by counteracting gene flow from sympatric hawthorn populations. Our findings confirm that postzygotic reproductive isolation can evolve as a pleiotropic consequence of host-associated adaptation, a central tenet of nonallopatric speciation. They also suggest that one reason for the paucity of reported fitness trade-offs is a failure to consider adequately costs associated with coordinating an insect’s life cycle with the phenology of its host plant.

Tsetse thrombin inhibitor: Bloodmeal-induced expression of an anticoagulant in salivary glands and gut tissue of Glossina morsitans morsitans

The tsetse thrombin inhibitor, a potent and specific low molecular mass (3,530 Da) anticoagulant peptide, was purified previously from salivary gland extracts of Glossina morsitans morsitans (Diptera: Glossinidae). A 303-bp coding sequence corresponding to the inhibitor has now been isolated from a tsetse salivary gland cDNA library by using degenerate oligonucleotide probes. The full-length cDNA contains a 26-bp untranslated segment at its 5′ end, followed by a 63-bp sequence corresponding to a putative secretory signal peptide. A 96-bp segment codes for the mature tsetse thrombin inhibitor, whose predicted molecular weight matches that of the purified native protein. Based on its lack of homology to any previously described family of molecules, the tsetse thrombin inhibitor appears to represent a unique class of naturally occurring protease inhibitors. Recombinant tsetse thrombin inhibitor expressed in Escherichia coli and the chemically synthesized peptide are both substantially less active than the purified native protein, suggesting that posttranslational modification(s) may be necessary for optimal inhibitory activity. The tsetse thrombin inhibitor gene, which is present as a single copy in the tsetse genome, is expressed at high levels in salivary glands and midguts of adult tsetse flies, suggesting a possible role for the anticoagulant in both feeding and processing of the bloodmeal.

Jasmonate is essential for insect defense in Arabidopsis

The signaling pathways that allow plants to mount defenses against chewing insects are known to be complex. To investigate the role of jasmonate in wound signaling in Arabidopsis and to test whether parallel or redundant pathways exist for insect defense, we have studied a mutant (fad3–2 fad7–2 fad8) that is deficient in the jasmonate precursor linolenic acid. Mutant plants contained negligible levels of jasmonate and showed extremely high mortality (≈80%) from attack by larvae of a common saprophagous fungal gnat, Bradysia impatiens (Diptera: Sciaridae), even though neighboring wild-type plants were largely unaffected. Application of exogenous methyl jasmonate substantially protected the mutant plants and reduced mortality to ≈12%. These experiments precisely define the role of jasmonate as being essential for the induction of biologically effective defense in this plant–insect interaction. The transcripts of three wound-responsive genes were shown not to be induced by wounding of mutant plants but the same transcripts could be induced by application of methyl jasmonate. By contrast, measurements of transcript levels for a gene encoding glutathione S-transferase demonstrated that wound induction of this gene is independent of jasmonate synthesis. These results indicate that the mutant will be a good genetic model for testing the practical effectiveness of candidate defense genes.

Discovery of genes involved with learning and memory: An experimental synthesis of Hirschian and Benzerian perspectives

The biological bases of learning and memory are being revealed today with a wide array of molecular approaches, most of which entail the analysis of dysfunction produced by gene disruptions. This perspective derives both from early “genetic dissections” of learning in mutant Drosophila by Seymour Benzer and colleagues and from earlier behavior-genetic analyses of learning and in Diptera by Jerry Hirsch and coworkers. Three quantitative-genetic insights derived from these latter studies serve as guiding principles for the former. First, interacting polygenes underlie complex traits. Consequently, learning/memory defects associated with single-gene mutants can be quantified accurately only in equilibrated, heterogeneous genetic backgrounds. Second, complex behavioral responses will be composed of genetically distinct functional components. Thus, genetic dissection of complex traits into specific biobehavioral properties is likely. Finally, disruptions of genes involved with learning/memory are likely to have pleiotropic effects. As a result, task-relevant sensorimotor responses required for normal learning must be assessed carefully to interpret performance in learning/memory experiments. In addition, more specific conclusions will be obtained from reverse-genetic experiments, in which gene disruptions are restricted in time and/or space.