Relationships between altitude,triatomine (Triatoma dimidiata) immune response and virulence of Trypanosoma cruzi,the causal agent of Chagas' disease

Little is known about how the virulence of a human pathogen varies in the environment it shares with its vector. This study focused on whether the virulence of Trypanosoma cruzi (Trypanosomatida: Trypanosomatidae), the causal agent of Chagas' disease, is related to altitude. Accordingly, Triatoma dimidiata (Hemiptera: Reduviidae) specimens were collected at three different altitudes (300, 700 and 1400 m a.s.l.) in Chiapas, Mexico. The parasite was then isolated to infect uninfected T. dimidiata from the same altitudes, as well as female CD‐1 mice. The response variables were phenoloxidase (PO) activity, a key insect immune response, parasitaemia in mice, and amastigote numbers in the heart, oesophagus, gastrocnemius and brain of the rodents. The highest levels of PO activity, parasitaemia and amastigotes were found for Tryp. cruzi isolates sourced from 700 m a.s.l., particularly in the mouse brain. A polymerase chain reaction‐based analysis indicated that all Tryp. cruzi isolates belonged to a Tryp. cruzi I lineage. Thus, Tryp. cruzi from 700 m a.s.l. may be more dangerous than sources at other altitudes. At this altitude, T. dimidiata is more common, apparently because the conditions are more beneficial to its development. Control strategies should focus activity at altitudes around 700 m a.s.l., at least in relation to the region of the present study sites.     

Inverse effects of recent warming on trees growing at the low and high altitudes of the Dabie Mountains,subtropical China

Understanding how tree rings of different species at different elevations respond to climate, and whether their relationship is stable over time is crucial not only for credible palaeoclimatic reconstructions, but also for better awareness of forest growth dynamics and therefore making scientific management decisions against a background of global warming. In this work, six tree-ring chronologies of Pinus taiwanensis at three sites from 800 to 1550 m above sea level (asl), and Pinus massoniana at three sites from 500 to 650 m asl were developed in the Dabie Mountains (DBS), subtropical China. In recent decades, only P. taiwanensis at 1550 m asl showed a positive growth-trend. Both P. taiwanensis at 800 m asl and three low-altitude P. massoniana at 500–650 m asl showed negative growth trends. Climate-growth relationship analyses revealed that 1) temperature was the dominant climatic factor that controlled tree-ring growth in DBS. It exerted most influence on trees growing at the lower and upper limit, than for trees growing at altitudes from 650 to 1450 m asl. Only precipitation in October positively influenced tree growth of P. massoniana at all three sites and P. taiwanensis at 800 m asl; 2) There was a shift in temperature’s impact on trees, that was from significantly negative relationship at the four lower altitudes, mainly for the current growing-season, to significantly positive relationship in previous February–July period at the highest altitude. The higher the altitude, the more significant the lag effect of temperature on trees; 3) The influence of temperature on tree growth at most altitudes were variable over time. The positive influence of temperature on trees at 1550 and 1450 m asl was comparatively stable during the early period of instrumental records. It strengthened evidently since the early 1990s, which is coincidental with the timing of the evident temperature increase in DBS. On the contrary, the negative impacts of temperature on tree growth at 800, 650 and 500 m asl had weakened since the early 1990s. Besides the increase of water use efficiency of trees, we speculated that the increasing influence of precipitation in May and July weakened the relationship between temperature and tree rings at low altitudes. This work points out that the upper and lower limits of forest in DBS offer the preferred locations for future sampling in climate reconstruction, but the stability of tree growth and climate over time should be considered. Moreover, forest management should give priority to altitude factors, in addition to tree species representation.     

Identifying factors determining the altitudinal distribution of the invasive pest leafminers Liriomyza huidobrensis and Liriomyza sativae

Abiotic and biotic factors that change with altitude can influence the distribution of herbivorous insects. We examined factors influencing the distribution of the generalist leafminers Liriomyza sativae Blanchard and Liriomyza huidobrensis Blanchard (Diptera: Agromyzidae), two pests of agricultural crops, in the tropical Dieng mountainous area of Central Java, Indonesia. Liriomyza huidobrensis predominated at altitudes above 700 m a.s.l. and was the only species collected above 1 400 m a.s.l. In contrast, L. sativae predominated below 600 m a.s.l. and was not found above 1 200 m where the average temperature was 20.7 °C. Parasitoid diversity decreased with altitude, but parasitism did not change. The distribution of neither species was affected by parasitoids; L. huidobrensis predominant at high altitudes was preferred by Opius parasitoids common at these altitudes. Intra‐ and interspecific competition was detected in laboratory experiments where larval density was high, but led to coexistence rather than species displacement. No competition was detected in a field experiment when larval density was low. However, L. sativae failed to reproduce at the highest altitude, whereas L. huidobrensis established at all altitudes. Host composition varied with altitude and one host (faba beans) preferred by L. huidobrensis was common at high altitudes. By relating published data on the performance of the leafminer species to altitudinal temperature changes, we were partly successful in predicting the altitude at which the dominant species switched. Temperature plays an overriding influence on the altitudinal distribution of leafminers.     

Altitudinal gradients in seed dynamics of Calluna vulgaris in eastern Scotland

Abstract. Relationships between seed deposition, size of soil seed banks and some of the environmental factors affecting them were assessed for Calluna vulgaris throughout its altitudinal range (150–960 m a.s.l.) in eastern Scotland. Seed rain was assessed using pitfall traps, collected every 5–10 wk for 3 yr; germinability was determined by laboratory incubation. Seed bank size was estimated, once only, by counting seedlings emerging from soil cores kept for 50 wk in a glasshouse. Seed deposition varied annually, was related to parent plant cover but always declined with altitude, falling sharply above 600 m a.s.l. Seed bank size was more closely correlated with the proportion of organic matter in the soil than with the amount of seed rain. Seed bank sizes declined gradually with altitude but did not differ significantly between four altitudinal zones. The mean density of buried seeds was less than half the mean annual seed rain at sites below 300 m a.s.l. but was over 200 × greater than annual seed rain above 800 m, suggesting that seeds buried at high altitudes remain viable for much longer than those at lower altitudes.     

Temperature-driven proliferation of Tetracapsuloides bryosalmonae in bryozoan hosts portends salmonid declines

Proliferative kidney disease (PKD) is an emerging disease of salmonid fishes. It is provoked by temperature and caused by infective spores of the myxozoan parasite Tetracapsuloides bryosalmonae, which develops in freshwater bryozoans. We investigated the link between PKD and temperature by determining whether temperature influences the proliferation of T. bryosalmonae in the bryozoan host Fredericella sultana. Herein we show that increased temperatures drive the proliferation of T. bryosalmonae in bryozoans by provoking, accelerating and prolonging the production of infective spores from cryptic stages. Based on these results we predict that PKD outbreaks will increase further in magnitude and severity in wild and farmed salmonids as a result of climate-driven enhanced proliferation in invertebrate hosts, and urge for early implementation of management strategies to reduce future salmonid declines.     

Altitudinal variation in life‐history traits in the lawn ground cricket,Polionemobius mikado

It has been reported that the lawn ground cricket, Polionemobius mikado (Orthoptera: Trigonidiidae), shows variations in voltinism and life‐history traits along latitude in Japan, but whether it shows variations along altitude has not been examined. The present study aims to determine whether there is variation in voltinism, body size and the incidence of embryonic diapause among populations of P. mikado at different altitudes in Kyoto, Japan. Six populations collected from 70 to 800 m a.s.l. showed a positive relationship between the adult head width and the altitude of sampling locality. This body size cline is attributed to the increasing proportion of larger univoltine individuals from low to high altitude. The incidence of diapause of the strain from altitude 800 m was approximately 100% when reared under natural photoperiods and temperatures from spring to summer at an altitude of 70 m, and was significantly higher than that of the strain from 70 m. These differences in life‐history traits suggest that the population of P. mikado at a higher altitude has adapted to a shorter length of the season available for growth.     

Carabid life-cycle strategies and climate change: a study on an altitude transect

Abstract.

• 1 There was little overlap in the species composition of carabid beetle assemblages sampled below 450 m and above 800 m on an altitude transect and the first axis of a DECORANA ordination was closely correlated with altitude (r₁₁= 0.93, P < 0.001), probably reflecting the differing temperature requirements of different species.
• 2 Life-cycle strategies of two low-altitude species, found predominantly below 600 m, and two species caught above 600 m a.s.l., have been determined, using mandible wear to identify whether the females breed in the calendar year that they emerge as adults or in the year following.
• 3 Nebria salina has an annual cycle at 630 m. Pterostichus madidus and Calathus fuscipes were both biennial at altitudes above 300 m although predominantly annual at low altitude. N.gyllenhali was biennial above 600 m and it is not known whether it is able to switch to an annual cycle at low altitude.
• 4 Both N.salina and N.gyllenhali ceased activity soon after emergence, an adaptation which preserves their mandibles from wear.
• 5 At altitudes of 305 m and 430 m, P.madidus and C.fuscipes entered the breeding season with 33% and 56% reduction in mandible tip length, possibly reducing their reproductive output.
• 6 The necessity for relatively sharp mandibles on entry into the breeding season may restrict the capacity of carabids to respond to a temperature change by switching from annual to biennial cycles, and vice versa, adding support to the suggestion that carabids are more likely to respond to climate change by shifting distributions than by physiological adaptation.

     

Evidence that infectious stages of Tetracapsula bryosalmonae for rainbow trout Oncorhynchus mykiss are present throughout the year

Proliferative kidney disease (PKD) is a hyperplastic condition of the lymphoid tissue of salmonids infected with the spores of Tetracapsula bryosalmonae, a myxozoan parasite formerly designated PKX, which has recently been described as a parasite of several species of bryozoans. The occurrence of PKD is generally associated with seasonal increase in water temperature, with research indicating that transmission of the disease does not occur below 12 to 13 degrees C. This suggested that the infectious stages are absent from about November to March/April. Here we document the transmission of PKD at water temperatures and seasons previously considered to be non permissive for PKD infection. The exposure of naive rainbow trout Oncorhynchus mykiss (Walbaum) to PKD-infected water ranging from 8 to 13 degrees C during the Autumn, Winter and early Spring, resulted in the infection of kidney interstitium once the trout were transferred to 16 degrees C. In addition, cohabitation studies were conducted with the bryozoan host Fredericella sultana collected from a river at times of low seasonal temperatures because this bryozoan species overwinters as living colonies. Cohabitation of trout with colonies of F sultana in parasite-free city water at 16 degrees C, also led to renal lymphoid tissue infection with the parasite and even to nephromegaly. Our results provide evidence that the infectious stages of T bryosalmonae for rainbow trout were present in the water throughout the entire year and that the impact of temperature on the development of PKD is primarily a result of the kinetics of Tetracapsula multiplication in bryozoan and fish hosts.     

Effects of temperature on phenological synchrony and altitudinal distribution of jumping plant lice (Hemiptera: Psylloidea) on dwarf willow (Salix lapponum) in Norway

Summary.

• 1 The geographical distributions of three species of jumping plant lice (psyllids) along an altitudinal transect (988–1300 m a.s.l.) in southern Norway were restricted within the range of their host plant Salix lapponum. One species, Cacopsylla propinqua, occurred at all sampling locations between 988 and 1222 m, whereas C.palmeni was confined to higher altitudes (1153–1222 m) and C.brunneipennis was more abundant at lower altitudes (988–1101 m).
• 2 C.brunneipennis and C.palmeni developed only on female catkins. Development times of catkins and psyllids were similar (approximately 50 days) and successful psyllid development depended on close phenological synchrony with catkins.
• 3 Thermal requirements for development of female catkins were greater at low altitude (988 m) compared with higher altitude (1222 m), showing local adaptation of S.lapponum to altitude. In general, thermal requirements of psyllids were less than those of catkins at the same location. C.brunneipennis had higher thermal requirements than C.palmeni.
• 4 Field experiments, using polythene enclosures to elevate temperatures at two sites at different altitudes (by 0.6–1.4 deg. C), showed that insects had an enhanced relative rate of development under elevated temperatures compared with their host plants.
• 5 Indices of phenological synchrony were calculated from thermal requirements of psyllids and catkins. Under elevated temperatures, phenological synchrony decreased at both sites. This resulted in the subsequent development of smaller adult insects at low altitude, although at higher altitude, insects developing under elevated temperatures were larger and had a higher survival rate compared with controls.
• 6 Effects of temperature on phenological synchrony may explain the limits to the geographical range of psyllids. The consequences of climate change on psyllid populations will depend on the effects of decreased phenological synchrony on insect development and this may differ within the insect's geographical range.

     

Nucleotide polymorphisms related to altitude and physiological traits in contrasting provenances of Norway spruce (<Emphasis Type="Italic">Picea abies</Emphasis>)

Variation of sequences of six EST-derived markers was investigated in three Norway spruce (Picea abies [L.] Karst.) provenances originating from different altitudes growing at two contrasting trial plots in Slovakia (Veľky Lom 450 m a.s.l., Mútne-Zákamenné 1,250 m a.s.l.) within a spin-off experiment of the IUFRO 1964/68 Inventory Provenance Experiment with Norway spruce. Single nucleotide polymorphisms (SNP) were identified and differences in allele frequencies at polymorphic sites were tested against altitude or associated with physiological and growth traits (chlorophyll a fluorescence, frost resistance, height, diameter, budburst phenology).     

Low oxygen pressure as a driving factor for the altitudinal decline in taxon richness of stream macroinvertebrates

The objective of this study was to explore the altitudinal decrease in local richness of stream macroinvertebrates. I compared the explicatory power of a mid-domain effect (MDE) null model and a number of selected contemporary ecological variables, with a special emphasis on the altitude-mediated decrease in temperature and oxygen availability as possible driving factors for the observed pattern. Benthic macroinvertebrates were sampled at 30 stream sites between 2,600 and 4,000 m a.s.l. in northern Ecuador. All four measures of local richness (total number of taxa, taxa in Surber samples, Fisher’s α index and rarefied richness) decreased with increasing altitude. The MDE null model, water temperature and dissolved oxygen also decreased with altitude, while other measured variables were uncorrelated with altitude. Minimum oxygen saturation had the highest explanatory power of the density-corrected Fisher’s α and rarefied richness (R = 0.48 and 0.52, respectively), but also minimum temperature (R = 0.48 and 0.41) and the MDE null model (R = 0.48 and 0.46) correlated significantly. Multiple regression analyses using several predictive variables showed that oxygen saturation had the greatest and only significant effect on density-corrected richness. The relationship between richness and oxygen corrected for the effect of altitude (using analyses of double residuals) was significant, whereas that of richness versus temperature was not. The results indicate that the decrease in richness with increasing altitude is mainly caused by a decrease in oxygen saturation rather than by a decrease in temperature. Levels of oxygen saturation such as those found at high altitudes do not appear to be lethal to any species, but could affect macroinvertebrates through long-term, sub-lethal effects. I suggest that low oxygen availability may limit biodiversity at high altitudes not only in the aquatic, but also in the terrestrial environment. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Photosynthetic pathway,chilling tolerance and cell sap osmotic potential values of grasses along an altitudinal gradient in Papua New Guinea

Summary A total of 22 grass species were examined from 5 sites spanning the altitudinal range 1550–4350 m.a.s.l. The presence of the C₃ or C₄ photosynthetic pathway was determined from ¹³C values and chilling tolerance was assessed on the basis of electrolyte leakage from leaf slices incubated on melting ice. Most of the grasses studied at the lower altitude sites of 1550 m.a.s.l. (annual mean of daily minimum temperature, 14.6° C) and 2600 m.a.s.l. (9.4° C) possessed C₄ photosynthesis and were chill-sensitive. The single except ion was Agrostis avenacea, a montane chill-resistant C₃ species which occurred at 2600 m.a.s.l. The three species apparently most sensitive to chilling were Ischaemum polystachyum, Paspalum conjugatum and Saccharum robustum, all occurring at 1550 m.a.s.l. At the higher altitude sites of 3280 (5.6° C), 3580 (4.0° C) and 4350 (–0.7°C) m.a.s.l., most of the grasses exhibited C₃ photosynthesis and were chill-resistant. However, an Upland population of the C₄ species, Miscanthus floridulus was found at 3280 m.a.s.l. which had acquired chill-resistance as confirmed by additional in vivo variable chlorophyll fluorescence measurements. Cell sap osmotic potential values of the upland grasses at altitudes of 3280–4350 m.a.s.l. were lower (–8.1 to –19.8 bars) than values in grasses from 1550 and 2600 m.a.s.l. (–3.9 to –7.5 bars) due mainly to the presence of non-electrolyte osmoticants, which may be involved in frost avoidance mechanism(s).Abbreviations ABA abscisic acid - F_R the maximal rate of rise of induced chlorophyll fluorescence - s osmotic potential     

Endemic gypsophytes composition delimitated by soil properties and altitude: From calciphytes to halophytes in the south–central Alborz Ranges

Specialized plant species have long served as geobotanical tools for locating mines and ores. Despite their importance, not much research has been dedicated to studying the ecology of endemic specialized plant species, such as those of gypsum or calcareous habitats. Here we describe and analyze the occurence of endemic plant species in gypsum habitats of the south–central Alborz Ranges (Semnan), Iran, in relation to altitude and soil properties. Ecological data and soil samples were collected from 120 plots along along an altitudinal gradient correlated with differences in soil properties. Forty seven plant species, including 6 species endemic to the Semnan area and 20 species endemic to Iran, were identified. The occurrence of the species were analyzed using canonical correspondence (CCA) and detrended correspondence Analysis (DCA), and based on the results the species were categorized as gypsophytes G₁ (1600–2245 m a.s.l.), calciphytes (1500–1700 m a.s.l.), gypsophytes G₂ (1300–1600 m a.s.l.) and halophytes (1100–1300 m a.s.l.). Gypsum content, elevation and salinity (Na content) were identified as the environmental factors having the largest effects on vegetation compositon. Endemic Semnan plant species included Astragalus fridae, Euphorbia gypsicola and Gypsophila mucronifolia at higher altitudes, and Astragalus semnanensis, Centaurea lachnopus and Nepeta eremokosmos at lower altitude gypsic soils. More frequent Iranian endemic plant species included Moltkia gypsaceae at higher altitudes, Echinops nizvanus and Acantholimon cymosum at lower altitude gypsic soils, Astragalus glaucacanthos, A. podolobus and A. microcephalus occurring mainly in calcic carbonate soil, and halophyte species such as Artemisia sieberi dominating at lower altitudes with more saline–alkaline soil.     

Notes on the biology of Eudonia mawsoni (Lepidoptera:Pyralidae) on subantarctic Macquarie Island

Eudonia mawsoni, the only moth breeding on subantarctic Macquarie Island, was sampled to measure density and sex ratios in different habitats and at different altitudes, and to investigate the distribution of colour morphs. Sites sampled ranged in altitude from 20 to 433 m above sea level, and included mire, short grassland, herbfield, feldmark and moss. Adult moths were widespread, occurring from sea level to the highest mountain (433 m a.s.l.). Mean density ranged from 0 to 2.3 m^–2. Frequencies of males and females differed significantly for only 6 of the 24 sampling events, with males predominant at 5 of those 6. Females predominated only in collections from a pure moss site, where they appeared to gather to oviposit. In some vegetation types, moth sex proportions differed significantlly from average proportions, with the proportion of females elevated in feldmark and moss, and depressed in mire. Colour morph distribution was significantly affected by both sex and altitude, with females darker than males and both sexes with a greater proportion of darker individuals at higher altitudes. Larvae occurred at sites ranging from sea level to 370 m a.s.l., usually in mosses. Their diet included mosses and some non-moss plant material.     

Species composition of termites of the Nyika plateau forests, northern Malawi, over an altitudinal gradient

Termites were surveyed at three altitudes (Brachystegia woodland at 1676 m and 1905 m, and Juniper woodland at 2210 m) in forests within the Nyika Plateau, northern Malawi. Sampling was by a standardized 100 m transect protocol. Termite diversity was highest in the mid‐altitude site and lowest in the Juniper forest. The assemblages were dominated by soil‐feeding termites in the Termitidae subfamilies Apicotermitinae and Termitinae, and included one new soldierless Apicotermitinae genus. The structure of the assemblages was clearly due to a mixture of altitudinal and site history factors. This was especially true of the lowest altitude forest where burning and other anthropogenic disturbance factors appear to have reduced termite diversity relative to the mid‐altitude site. The Nyika plateau shows a much higher diversity at mid‐altitudes than similar SE Asian sites, probably due to the larger area of highland in Africa than in SE Asia. In addition, the clade composition of the Nyika assemblages differs completely from that found at similar altitudes in SE Asia. This preliminary study supports the hypothesis that mid‐ to high‐ altitude assemblages in both SE Asia and Africa appear to be derived from depauperated random subsets of the lowland fauna rather than from clades specifically adapted to higher altitudes.     

Climatic signals in tree ring of Picea schrenkiana along an altitudinal gradient in the central Tianshan Mountains, northwestern China

Tree-ring samples of Picea schrenkiana (Fisch. et Mey) were studied along an altitudinal gradient in the central Tianshan Mountains, and ring-width chronologies were developed for three sites at different altitudes: low-forest border (1600–1700 m a.s.l.), interior forest (2100–2200 m a.s.l.), and upper treeline (2600–2700 m a.s.l.). Annual ring-width variations were similar among the three sites but variability was greatest at the low-forest border site. The statistical characters of the chronologies showed that mean sensitivity (MS) and standard deviation (SD) decreased with increasing elevation. In other words, the response of tree growth to environmental changes decreased with increasing altitude. To understand the differing response of trees at different elevations to the environmental changes, response function analysis was used to study the relationships between tree-ring widths and mean monthly temperature and total monthly precipitation from 1961 to 2000. The results showed that precipitation was the most important factor limiting tree radial growth in the arid central Tianshan Mountains, precipitation in August of the prior growth year played an important role on tree's radial growth across the entire altitudinal gradient even at the cold, high-elevation treeline site. It is expected that with increasing altitude air temperature decreased and precipitation increased, the importance of precipitation on tree growth decreased, and the response of tree growth to environmental changes decreased, too. This conclusion may be helpful to understand and research the relationship between climatic change and tree growth in arid and semiarid area.     

Altitudinal distribution of chytrid (Batrachochytrium dendrobatidis) infection in subtropical Australian frogs

The disappearance of amphibian populations from seemingly pristine upland areas worldwide has become a major focus of conservation efforts in the last two decades, and a parasitic chytrid fungus, Batrachochytrium dendrobatidis, is thought to be the causative agent of the population declines. We examined the altitudinal distribution of chytrid infections in three stream‐dwelling frog species (Litoria wilcoxii, L. pearsoniana and L. chloris) in southeast Queensland, Australia, and hypothesized that if B. dendrobatidis were responsible for the disappearance of high‐altitude frog populations, infection prevalence and intensity would be greatest at higher altitudes. Overall, 37.7% of the 798 adult frogs we sampled were infected with B. dendrobatidis, and infections were found in all the populations we examined. Contrary to our initial hypothesis, we found no consistent evidence that high‐altitude frogs were more likely to be infected than were lowland frogs. Further, the intensity of fungal infections (number of zoospores) on high‐altitude frogs did not differ significantly from that of lowland frogs. Batrachochytrium dendrobatidis appears to be capable of infecting frogs at all altitudes in the subtropics, suggesting that all populations are at risk of decline when conditions favour disease outbreaks. We did find evidence, however, that chytrid infections persist longer into summer in upland as compared with lowland areas, suggesting that montane amphibian populations remain susceptible to disease outbreaks for longer periods than do lowland populations. Further, we found that at high altitudes, temperatures optimal for chytrid growth and reproduction coincide with frog metamorphosis, the life‐stage at which frogs are most susceptible to chytrid infections. While these altitudinal differences may account for the differential population‐level responses to the presence of B. dendrobatidis, the reason why many of southeast Queensland's montane frog populations declined precipitously while lowland populations remained stable has yet to be resolved.     

Altitude affects the distribution and abundance of two non‐native insect pests of the common walnut

The leaf miner Coptodisca lucifluella and the carpophagous Rhagoletis completa, of American origin, are two non‐native walnut (Juglans spp.) pests in Italy. For the Friuli Venezia Giulia region (FVG) (N‐E Italy), C. lucifluella is not yet listed, while R. completa has been present for over 25 years. During 2015, samples of leaves and fruits were collected from 219 single old common walnut trees (Juglans regia) placed at different altitudes (0–1,073 m a.s.l.) in FVG to detect the distribution and abundance of both pests. Samples of leaf miner larvae and their parasitoids were subjected to mitochondrial DNA analysis for identification. C. lucifluella has been found in 55 out of 219 sites. The species has been identified by typical leaf symptoms and by its DNA barcode. This is the first report of the species for FVG. The leaf miner distribution was negatively correlated with altitude. The species has not been observed at sites over 600 m a.s.l. Larvae were parasitized by native parasitoids identified as belonging to the genus Chrysocharis by morphological features and by DNA barcode. R. completa has been found in 89 out of 165 sites on walnut trees with fruits. The infestation level was very high in lowland localities. At sites over 700 m a.s.l., no infestation was found. Both species are widespread in the region, and their occurrence is significantly affected by altitude. Data suggest that walnut trees could be cultivated in some mountain areas without the need to control R. completa with insecticides.     

The phylogeography of salmonid proliferative kidney disease in Europe and North America

Salmonid proliferative kidney disease (PKD) is caused by the myxozoan Tetracapsuloides bryosalmonae. Given the serious and apparently growing impact of PKD on farmed and wild salmonids, we undertook a phylogeographic study to gain insights into the history of genealogical lineages of T. bryosalmonae in Europe and North America, and to determine if the global expansion of rainbow trout farming has spread the disease. Phylogenetic analyses of internal transcribed spacer 1 sequences revealed a clade composed of all North American sequences plus a subset of Italian and French sequences. High genetic diversity in North America and the absence of genotypes diagnostic of the North American clade in the rest of Europe imply that southern Europe was colonized by immigration from North America; however, sequence divergence suggests that this colonization substantially pre-dated fisheries activities. Furthermore, the lack of southern European lineages in the rest of Europe, despite widespread rainbow trout farming, indicates that T. bryosalmonae is not transported through fisheries activities. This result strikingly contrasts with the commonness of fisheries-related introductions of other pathogens and parasites and indicates that fishes may be dead-end hosts. Our results also demonstrate that European strains of T. bryosalmonae infect and induce PKD in rainbow trout introduced to Europe.     

Parasitism of Hypothenemus hampei (Coleoptera: Scolytidae) in different farming systems and altitudes of Mount Elgon,Uganda

Altitude and farming system play a vital role in modifying the niche for arthropods, by directly influencing microclimatic conditions, the quality and quantity of vegetative cover, which act variably on the behaviour of the pests, and their natural enemies. The objective of the study was to determine their effect on the abundance and parasitism of the Coffee berry borer (Hypothenemus hampei) in the Mount Elgon region. Altitude was categorized as: low (1,400–1,499 m.a.s.l); mid (1,500‐1,679 m.a.s.l); and high (1,680–2,100 m.a.s.l), and farming system was categorized as: Coffee monocrop; Coffee + annual; Coffee + banana; and Coffee + banana + shade trees. For each altitudinal range, each farming system was represented three times. The study was in two districts of the Mt. Elgon, covering a total of 72 Arabica Coffee study sites. The work involved field pest infestation inventories, followed by laboratory rearing for the abundance and parasitism studies. The results revealed highly significant interactions between altitude and farming system in influencing the abundance of the pest and its four parasitoids: Phymastichus coffea, Cephalonomia stephanoderis, Prorops nasuta and Heterospilus coffeicola. C. stephanoderis was highest in the mid‐altitudes within Coffee + banana+shade tree system; P. nasuta was highest at high altitude within Coffee + banana system; P. coffea was most abundant at mid‐altitude within Coffee + banana system, whereas H. coffeicola was highest at high altitude within the Coffee + annual cropping system. H. hampei counts were highest at low altitudes, especially in the Coffee + annual system. Some of these trends can be explained by the condition of the microclimate in the Coffee fields. There was a negative relationship between temperature and abundance of all the four parasitoids. Only C. stephanoderis had a relationship (+) with semi‐natural vegetation species counts. And only H. coffeicola had a relationship (+) with light intensity. These contrasted with H. hampei, which was positively related to temperature and negatively to light intensity.