Parasitoid complex and bionomics ofApanteles polychrosidis(Hymenoptera: Braconidae) on the ash leaf-cone roller (Lepidoptera: Gracillariidae)

2013 ◽  
Vol 145 (4) ◽  
pp. 416-429 ◽  
Author(s):  
T.J. Wist ◽  
M.L. Evenden
Keyword(s):  
Abiotic Factors ◽  
Host Density ◽  
Tree Canopy ◽  
Host Acceptance ◽  
Choristoneura Rosaceana ◽  
Canadian Prairie ◽  
Parasitoid Complex ◽  
Larval Host ◽  
Leaf Mining ◽  
Caloptilia Fraxinella

AbstractThe ash leaf-cone roller,Caloptilia fraxinella(Ely) (Lepidoptera: Gracillariidae) is an introduced leaf-mining moth of horticultural ash trees (FraxinusLinnaeus; Oleaceae) in Western Canadian Prairie cities. Here, we identify the dominant parasitoid of this leaf-mining moth asApanteles polychrosidisVierek (Hymenoptera: Braconidae) and document its emergence pattern, courtship, mating, and host acceptance behaviours.Apanteles polychrosidisadult emergence is protandrous and mating occurs soon after female emergence. MaleA. polychrosidiscan mate multiple times in short sequence with a mean copulation time of 49 seconds. It is likely thatA. polychrosidisoverwinters in an alternate larval host, after emergence fromC. fraxinella. Mated femaleA. polychrosidisreadily parasitise an alternate host, the obliquebanded leafroller (Choristoneura rosaceana(Harris); Lepidoptera: Tortricidae), known to overwinter as larvae. Through rearingC. fraxinellapupae, we describe the remainder of the parasitoid complex ofC. fraxinella, in order of parasitism rate, asDiadegmaFörster (nearDiadegmafenestrale(Holmgren)) (Hymenoptera: Ichneumonidae), threeSympiesisFörster species (Hymenoptera: Eulophidae) (Sympiesissericeicornis(Nees von Esenbeck), one nearSympiesisviridula(Thomson) and one unknown species), andPteromalus phycidis(Ashmead) (Hymenoptera: Pteromalidae) and show that severalSympiesisspecies can be hyperparasitic onA. polychrosidis.Caloptilia fraxinelladensity within the tree canopy is highest in the lower canopy. Host density and abiotic factors such as temperature and light intensity do not influence the within-canopy distribution of most parasitoids exceptSympiesisspecies, which preferred the northern canopy.

scholarly journals Host Plant Volatile Lures Attract Apanteles polychrosidis (Hymenoptera: Braconidae) to Ash Trees Infested With Caloptilia fraxinella (Lepidoptera: Gracillariidae)

2021 ◽  
Vol 9 ◽  
Author(s):  
Sarah M. McPike ◽  
Maya L. Evenden
Keyword(s):  
Biological Control ◽  
Field Experiments ◽  
Biological Control Agent ◽  
Host Density ◽  
Green Leaf Volatiles ◽  
Tree Canopy ◽  
Parasitism Rate ◽  
High Release ◽  
Ash Trees ◽  
Caloptilia Fraxinella

Caloptilia fraxinella Ely (Lepidoptera: Gracillariidae), the ash leaf-cone roller, is an aesthetic pest of horticultural ash trees (Oleaceae, Genus Fraxinus) in prairie communities across Canada. Because pesticide use is undesirable in urban centers, biological control of C. fraxinella is a preferred approach. The native parasitoid wasp, Apanteles polychrosidis Vierek (Hymenoptera: Braconidae), has shifted hosts and is the primary parasitoid of C. fraxinella in Edmonton, Alberta, Canada, and has potential as a biological control agent. Here, in an effort to increase parasitism of C. fraxinella, lures releasing methyl salicylate (MeSA) and two green leaf volatiles (GLVs), [(Z)-3-hexenol, and (Z)-3-hexenyl-acetate], at both low and high release rates, were tested to enhance attraction and retention of A. polychrosidis in infested ash trees. Attraction of A. polychrosidis to baited trees was measured by capture on yellow sticky cards positioned in the tree canopy, and wasp activity was assessed by the parasitism rate of C. fraxinella. More male and female A. polychrosidis were captured on yellow sticky traps positioned in trees baited with the low dose of both MeSA + GLVs than to unbaited, infested ash trees. The increased attraction of wasps did not correlate with an increase in parasitism of C. fraxinella. The high release rate lures did not enhance attraction of A. polychrosidis to infested ash trees. Parasitism rate, however, was negatively correlated with host density in both field experiments. There was no evidence of close-range attraction to lures in an olfactometer assay. Synthetic HIPVs attract A. polychrosidis to ash trees infested with C. fraxinella, but the effect of wasp attraction on parasitism rate requires further research if HIPVs are to be used to enhance biological control in this system.

Abiotic and biotic influences on Bromus tectorum invasion and Artemisia tridentata recovery after fire

2011 ◽  
Vol 20 (4) ◽  
pp. 597 ◽  
Author(s):  
Lea Condon ◽  
Peter J. Weisberg ◽  
Jeanne C. Chambers
Keyword(s):  
Bromus Tectorum ◽  
Structural Equation Models ◽  
Abiotic Factors ◽  
Artemisia Tridentata ◽  
Canopy Cover ◽  
Tree Canopy ◽  
Herbaceous Species ◽  
Tree Canopy Cover ◽  
Negative Effect ◽  
Species Cover

Native sagebrush ecosystems in the Great Basin (western USA) are often invaded following fire by exotic Bromus tectorum (cheatgrass), a highly flammable annual grass. Once B. tectorum is established, higher fire frequencies can lead to local extirpation of Artemisia tridentata ssp. vaseyana (mountain big sagebrush) and have cascading effects on sagebrush ecosystems and the species that depend on them. We conducted a landscape-scale observational study to examine the distribution and cover of B. tectorum and A. tridentata 6 years after a large wildland fire. We used structural equation models to quantify the interacting influences of pre-fire tree canopy cover, perennial species cover, distance from potential seed source, and site environment on post-fire cover of B. tectorum and A. tridentata. Results confirmed a hypothesised negative effect of pre-fire tree canopy cover on post-fire cover of A. tridentata. Site- and landscape-level abiotic factors influenced pre-fire tree canopy cover, which, in turn, influenced the probability of rapid recovery to A. tridentata. However, B. tectorum cover was primarily influenced by a positive effect of incident solar radiation and a negative effect of perennial herbaceous species cover. Restoration efforts to reduce tree canopy cover should be limited to productive sites with sufficient cover of perennial herbaceous species to facilitate site recovery.

Biology of Caloptilia fraxinella (Lepidoptera: Gracillariidae) on ornamental green ash, Fraxinus pennsylvanica (Oleaceae)

2009 ◽  
Vol 141 (1) ◽  
pp. 31-39 ◽  
Author(s):  
M.L. Evenden
Keyword(s):  
Management Program ◽  
Biological Information ◽  
Fraxinus Pennsylvanica ◽  
Immature Stages ◽  
Green Ash ◽  
Emergence Period ◽  
Leaf Mining ◽  
Ash Trees ◽  
A Site ◽  
Caloptilia Fraxinella

AbstractThe ash leaf cone roller, Caloptilia fraxinella (Ely), is a leaf-mining moth that has recently become a significant pest of horticultural ash, Fraxinus L., species in communities throughout the western prairie provinces of Canada. The study examines the spatial and temporal within-host distribution of immature stages of C. fraxinella on green ash, Fraxinus pennsylvanica Marsh. Female C. fraxinella showed a preference for oviposition sites in the lower canopy and on the south side of the tree at the beginning and middle of the 3-week oviposition period, respectively, but no preference at the end of the period. Oviposition was constrained temporally and occurred mainly just after green ash bud flush. Immature stages were sampled throughout the growing season, and measured widths of larval head capsules showed five instars. Fourth-instar larvae disperse from the mined leaflet to a new leaflet, roll it into a cone, and pupate. Neither canopy height nor ordinal direction affected the position of larvae in the canopy, but numbers of immature stages varied by tree within a site. Female and male moths eclose from rolled leaf cones synchronously throughout the emergence period. The study provides some of the basic biological information required to design an integrated pest management program to target this emerging pest of horticultural ash trees.

Divergent biotic and abiotic filtering of root endosphere and rhizosphere soil fungal communities along ecological gradients

2020 ◽  
Vol 96 (7) ◽  
Author(s):  
Candice Y Lumibao ◽  
Elizabeth R Kimbrough ◽  
Richard H Day ◽  
William H Conner ◽  
Ken W Krauss ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Abiotic Factors ◽  
Canopy Cover ◽  
Host Density ◽  
Fungal Communities ◽  
Biotic Factors ◽  
Wetland Ecosystems ◽  
Rhizosphere Fungi ◽  
Salinity Levels ◽  
Salinity Water

ABSTRACT Plant roots assemble in two distinct microbial compartments: the rhizosphere (microbes in soil surrounding roots) and the endosphere (microbes within roots). Our knowledge of fungal community assembly in these compartments is limited, especially in wetlands. We tested the hypothesis that biotic factors would have direct effects on rhizosphere and endosphere assembly, while abiotic factors would have direct and indirect effects. Using a field study, we examined the influences of salinity, water level and biotic factors on baldcypress (Taxodium distichum) fungal communities. We found that endosphere fungi, unlike rhizosphere fungi, were correlated with host density and canopy cover, suggesting that hosts can impose selective filters on fungi colonizing their roots. Meanwhile, local abiotic conditions strongly influenced both rhizosphere and endosphere diversity in opposite patterns, e.g. highest endosphere diversity (hump-shaped) and lowest rhizosphere diversity (U-shaped) at intermediate salinity levels. These results indicate that the assembly and structure of the root endosphere and rhizosphere within a host can be shaped by different processes. Our results also highlight the importance of assessing how environmental changes affect plant and plant-associated fungal communities in wetland ecosystems where saltwater intrusion and sea level rise are major threats to both plant and fungal communities.

DISPERSAL AND ESTABLISHMENT OF PLEOLOPHUS BASIZONUS (HYMENOPTERA: ICHNEUMONIDAE)

1970 ◽  
Vol 102 (9) ◽  
pp. 1102-1111 ◽  
Author(s):  
Peter W. Price
Keyword(s):  
Host Density ◽  
Jack Pine ◽  
Population Estimates ◽  
Natural Mortality ◽  
Mortality Factors ◽  
River Watershed ◽  
Parasitoid Complex ◽  
Important Addition ◽  
The Mean ◽  
Absolute Population

AbstractPleolophus basizonus (Gravenhorst) is a parasitoid from Europe introduced in Canada and liberated between 1939 and 1949 to supplement natural mortality factors of sawfly populations. Three recoveries reported in the literature show that the parasitoid has dispersed 81 km at 4.3 km per year in Ontario, between 109 and 161 km at 4.5 and 5.6 km per year in Quebec, and 172 km at 8.6 km per year in Michigan. Dispersal occurs by walking, possibly by short flights and by water while the parasitoid is within the host cocoon. Female parasitoids do not fly unless disturbed and dispersal by water cannot account for their movement in Quebec. In observation trays, the mean rate of travel on the ground by female parasitoids was 20.9 cm per minute. This speed is sufficient to account for the rates of dispersal recorded in the field. The parasitoid was present in every jack pine stand sampled between 1965 and 1968 in the western part of the St. Maurice River watershed in Quebec. The most abundant host was Neodiprion swainei Middleton. Absolute population estimates indicate that the parasitoid responds positively to host density and that it is an important addition to the native parasitoid complex.

scholarly journals Parasitoid complex (Hymenoptera: Eulophidae) of the leaf-mining fly Chromatomyia horticola (Goureau) (Diptera: Agromyzidae) in Russia

2014 ◽  
Vol 43 (1) ◽  
pp. 125-134 ◽  
Author(s):  
Zoya Yefremova ◽  
I. Strakhova ◽  
V. Kravchenko ◽  
M. von Tschirnhaus ◽  
E. Yegorenkova
Keyword(s):  
Parasitoid Complex ◽  
Leaf Mining

scholarly journals Temporal and spatial changes in phyllosphere microbiome of acacia trees growing in arid environments

2021 ◽  
Author(s):  
Ashraf Al-Ashhab ◽  
Shiri Meshner ◽  
Rivka Alexander-Shani ◽  
Hana Dimerets ◽  
Michael Brandwein ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Bacterial Diversity ◽  
Air Temperature ◽  
Bacterial Communities ◽  
Abiotic Factors ◽  
Keystone Species ◽  
Tree Canopy ◽  
Arid Environments ◽  
Acacia Tortilis ◽  
Acacia Species

Abstract Background: The evolutionary relationships and interactions between plants and their microbiomes are of high importance to the survival of plants in extreme conditions. Changes in the plant’s microbiome can affect plant development, growth and health. Along the arid Arava, southern Israel, acacia trees (Acacia raddiana and Acacia tortilis) are considered keystone species. In this study, we investigated the ecological effects of plant species, microclimate (different areas within the tree canopy) and seasonality on the epiphytic and endophytic microbiomes associated with these two tree species. One hundred and thirty nine leaf samples were collected throughout the year and their microbial communities were assessed using 16S rDNA gene amplified with five different primers (targeting different gene regions) and sequenced (150 bp paired-end) on an Illumina MiSeq sequencing platform.Results: Epiphytic bacterial diversity estimates (Shannon-Wiener, Chao1, Simpson and observed number of OTUs), were found to be nearly double compared to endophyte counterparts, in addition epi- and endophyte communities were significantly different from each other. Interestingly, the epiphytic bacterial diversity was similar in the two acacia species but the canopy sides and sample months exhibited different diversity, while the endophytic bacterial communities were different in the two acacia species but similar throughout the year. Abiotic factors, such as air temperature and precipitation, were shown to significantly affect both epi- and endophytes communities. Bacterial community compositions showed that Firmicutes dominate Acacia raddiana and Proteobacteria dominate Acacia tortilis; these bacterial communities only consisted of a small number of bacterial families mainly Bacillaceae and Comamonadaceae in the endophyte for A. raddiana and A. tortilis, respectively, and Geodematophilaceae and Micrococcaceae for epiphyte bacterial communities. Interestingly, about 60% of the obtained bacterial classification were unclassified below family level. Conclusions: These results shed light on the unique desert phyllosphere microbiome highlighting the importance of multiple genotypic and abiotic factors in shaping the epiphytic and endophytic microbial communities. This study also shows that only a few bacterial families dominate both epi- and endophytes, highlighting the importance of climate change (precipitation, air temperature and humidity) in affecting arid land ecosystems where acacia trees are considered keystone species.

scholarly journals Interspecific competition among aphid parasitoids: molecular approaches reveal preferential exploitation of parasitized hosts

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Sebastián Ortiz-Martínez ◽  
Jean-Sébastien Pierre ◽  
Joan van Baaren ◽  
Cécile Le Lann ◽  
Francisca Zepeda-Paulo ◽  
...  
Keyword(s):  
Host Range ◽  
Interspecific Competition ◽  
Host Density ◽  
Aphidius Ervi ◽  
Host Acceptance ◽  
Parasitoid Species ◽  
Narrow Host Range ◽  
Molecular Approaches ◽  
Aphid Density ◽  
Aphid Parasitoids

AbstractWhen a guild of species exploit the same limited resources, interspecific competition induces the exclusion of inferior competitors, in which case, interspecific recognition mechanisms are needed. Here, we address resource partitioning and interspecific competition among three main solitary parasitoid species attacking the same host resource, the aphid Sitobion avenae in wheat fields. Optimal host acceptance models predict that parasitoid species should prefer attacking unparasitized hosts when they are available in order to maximize their fitness, as already parasitized hosts are less valuable for laying eggs, especially for inferior competitors. Therefore, we expected the level of competition (multiparasitism) in the field to increase at low host density. By using a combination of taxonomical (determination) and molecular (PCR-based) approaches, we assessed the species of all parasitoid adults and immature stages within aphid hosts. Our results demonstrate that, early in the season, the multiparasitism rates were low, whereas they were high in the mid-late season, corresponding to an aphid density decrease over time. Moreover, parasitoid species could not have been exploiting host resources randomly and the better competitor, Aphidius ervi, seemed to be foraging preferentially on hosts already parasitized by the inferior competitor A. rhopalosiphi, even when unparasitized hosts were still available. This could be due to differences in their host detection capability, as species with a narrow host range may be better at detecting their hosts in comparison with species with a greater host range, such as A. ervi, with a greater host range within the guild. Our study suggests differences in the host exploitation of two prevalent parasitoid species through the main period of aphid colonization, which still allowed the coexistence of a third inferior competitor (A. rhopalosiphi) within the assemblage, in spite of some negative interactions (multiparasitism) and redundancies.

scholarly journals Host density and parasitoid presence interact and shape the outcome of a tritrophic interaction on seeds of wild lima bean

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Maximilien A. C. Cuny ◽  
Juan Traine ◽  
Carlos Bustos-Segura ◽  
Betty Benrey
Keyword(s):  
Negative Impact ◽  
Interactive Effect ◽  
Larval Density ◽  
Host Density ◽  
Lima Bean ◽  
Phaseolus Lunatus ◽  
Insect Communities ◽  
Mediated Effects ◽  
Larval Host ◽  
The Impact

AbstractThe interaction between the seed beetle Zabrotes subfasciatus and its parasitoid Stenocorse bruchivora, was investigated on seeds of two populations of wild lima bean, Phaseolus lunatus. By manipulating the number of beetle larvae per seed and the presence of parasitoids, we determined how factors related to beetle larvae density, the seed in which they feed and the parasitoid, may interact and affect host and parasitoid survival. Results showed that an increase in larval beetle density had a negative impact on beetle performance. This effect cascaded up to parasitoids, high larval density strongly reduced parasitoid emergence. Also, parasitoid presence resulted in faster beetle development and lower female weight. An interactive effect between larval host density and parasitoid presence affected the number of insects that emerged from the seeds. Beetle performance was better in the bean population with the largest seeds, while parasitoid emergence was the lowest in these seeds. This study shows that the impact of parasitoids on seed beetles is contingent on the interaction between density-mediated (direct mortality) and trait-mediated (e.g. non-consumptive) effects. Indirect trait-mediated effects of natural enemies are likely prevalent across insect communities, understanding their role in driving host-parasitoid interactions can have important implications for biological control.

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