ATTRACTIVENESS OF LOGS CONTAINING FEMALE SPRUCE BEETLES, DENDROCTONUS OBESUS (COLEOPTERA: SCOLYTIDAE)

1968 ◽  
Vol 100 (7) ◽  
pp. 769-776 ◽  
Author(s):  
E. D. A. Dyer ◽  
D. W. Taylor
Keyword(s):  
Natural Populations ◽  
Field Studies ◽  
Flight Period ◽  
Low Level ◽  
Spruce Beetle

AbstractField studies were carried out on effect of attack by unmated spruce beetles, Dendroctonus obesus (Mann.) on log attractiveness. Test logs were screen-covered or sprayed with insecticide. Trays beneath logs, with glass-barrier traps beside them, were used to measure response of beetles from natural populations.About 89% of the beetles attracted at six replicate sites were taken at logs containing introduced females. Males always predominated in responses to these logs. After the initial flight, about equal numbers of each sex responded to logs without introduced females. Response to the latter dropped to a low level after the initial flight, but beetles continued to respond well to logs attacked by females throughout the flight period. Use of increased attractiveness to logs following introduction of female beetles shows promise as a means of studying, directing, or controlling infestations of the spruce beetle.

Interactions of Four Herbicides with Rhizoctonia solani on Seedling Cotton

Weed Science ◽  
1968 ◽  
Vol 16 (4) ◽  
pp. 453-456 ◽  
Author(s):  
James M. Chandler ◽  
P. W. Santelmann
Keyword(s):  
Gossypium Hirsutum ◽  
Rhizoctonia Solani ◽  
Field Studies ◽  
Antagonistic Effect ◽  
Field Conditions ◽  
Growth Chamber ◽  
Seedling Disease ◽  
Low Level ◽  
High Level

Growth chamber and field studies were conducted to investigate the possibility of an interaction between the herbicides 4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline (nitralin), a,a,a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin), 3- (m-tri-fluromethylphenyl)-1,1-dimethylurea (fluometuron), and 2,4-bis(isopropylamino)-6-methylmercapto-s-triazine (prometryne), and the seedling disease organism Rhizoctonia solani Kuehn in cotton (Gossypium hirsutum L.). When high levels of trifluralin or prometryne were used in the growth chamber, an interaction with the pathogen that was injurious to the cotton occurred. Prometryne and fluometuron produced an antagonistic effect on R. solani.Under field conditions, R. solani usually caused cotton injury. Interactions injurious to the cotton occurred between trifluralin and a low level of R. solani and between nitralin and a high level R. solani infestation. No interactions occurred with fluometuron or prometryne. In all instances, the effect occurred only when the herbicides were being used at high rates.

The status and distribution of Carex subimpressa (Cyperaceae)

1986 ◽  
Vol 64 (1) ◽  
pp. 227-232 ◽  
Author(s):  
A. A. Reznicek ◽  
P. M. Catling
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Natural Populations ◽  
Field Studies ◽  
Diagnostic Character ◽  
Wide Area ◽  
Hybrid Origin ◽  
The Status ◽  
Specific Rank ◽  
Scanning Electron

Carex subimpressa, originally described as a hybrid of C. hyalinolepsis and C. lanuginosa, has been reported over a wide area and beyond the range of C. hyalinolepis. Consequently it has been accorded specific rank. Various aspects of morphology reflected in scatter diagrams as well as intermediate stomatal structure revealed through scanning electron microscopy and sectioning support the hybrid origin as originally proposed. This is further supported by field studies of natural populations where both putative parents were invariably present. Reports from beyond the range of one or both parents are the result of misidentification. The diagnostic character combination includes sparsely pubescent perigynia 4.2–6.4 mm long, with relatively short beaks, leaves 4.5–11 mm wide, and ligules 1.8–9 mm long.

scholarly journals Vive la résistance: genome-wide selection against introduced alleles in invasive hybrid zones

2016 ◽  
Vol 283 (1843) ◽  
pp. 20161380 ◽  
Author(s):  
Ryan P. Kovach ◽  
Brian K. Hand ◽  
Paul A. Hohenlohe ◽  
Ted F. Cosart ◽  
Matthew C. Boyer ◽  
...  
Keyword(s):  
Invasive Species ◽  
Rainbow Trout ◽  
Natural Populations ◽  
Cutthroat Trout ◽  
Field Studies ◽  
Selective Advantage ◽  
Hybrid Zones ◽  
Introduced Fish ◽  
Westslope Cutthroat Trout ◽  
Genome Wide

Evolutionary and ecological consequences of hybridization between native and invasive species are notoriously complicated because patterns of selection acting on non-native alleles can vary throughout the genome and across environments. Rapid advances in genomics now make it feasible to assess locus-specific and genome-wide patterns of natural selection acting on invasive introgression within and among natural populations occupying diverse environments. We quantified genome-wide patterns of admixture across multiple independent hybrid zones of native westslope cutthroat trout and invasive rainbow trout, the world's most widely introduced fish, by genotyping 339 individuals from 21 populations using 9380 species-diagnostic loci. A significantly greater proportion of the genome appeared to be under selection favouring native cutthroat trout (rather than rainbow trout), and this pattern was pervasive across the genome (detected on most chromosomes). Furthermore, selection against invasive alleles was consistent across populations and environments, even in those where rainbow trout were predicted to have a selective advantage (warm environments). These data corroborate field studies showing that hybrids between these species have lower fitness than the native taxa, and show that these fitness differences are due to selection favouring many native genes distributed widely throughout the genome.

scholarly journals Carex secalina (Cyperaceae), a critically endangered species of Europe: historic and new localities in Poland

2011 ◽  
Vol 78 (4) ◽  
pp. 311-320 ◽  
Author(s):  
Marlena Lembicz ◽  
Agnieszka Bogdanowicz ◽  
Julian Chmiel ◽  
Waldemar Żukowski
Keyword(s):  
Natural Populations ◽  
Field Studies ◽  
Reproduction Rate ◽  
Critically Endangered Species ◽  
Priority Task ◽  
Anthropogenic Habitat ◽  
New Localities ◽  
Population Sizes ◽  
Agricultural Use ◽  
Animal Grazing

<em>Carex secalina</em>, a species recognized as extinct in Poland for 40 years, was re-discovered in 2000 and it’s natural populations covered by monitoring. From among nine historic localities, only for two - Jacewo and Turzany, in the vicinity of Inowrocław - the occurrence of the species was confirmed. In the course of the field studies, six new localities, not previously recorded in literature, were discovered. The sedge occupies sub-halophytic habitats in which it occurs along with halophytic species (particularly, such as <em>Glaux maritima</em> and <em>Pucinellia distans</em>) and a group of ruderal taxons. One of the newly discovered localities of <em>C. secalina</em> comprises an anthropogenic habitat. On the whole, the population sizes ranged from 20 to 350 individuals. The studies revealed a positive correlation between the size of a population and cattle pasturing, i.e. <em>C. secalina</em> forms the largest populations in the habitats remaining under the intense pressure of grazing and treading. Moreover, it was found that the high generative reproduction rate compensates the damage caused by animal grazing. The results suggest that an active protection of the sedge populations through the agricultural use of its habitats is the only effective way of securing it’s further occurrence in Poland, while including the sub-halophytic pastures with <em>C. secalina</em> in the agricultural and environmental program should be a priority task in the nearest future.

scholarly journals Abiotic drivers of protein abundance variation among natural populations

2020 ◽  
Author(s):  
Joshua Niklas Ebner ◽  
Danilo Ritz ◽  
Stefanie von Fumetti
Keyword(s):  
Environmental Change ◽  
Natural Populations ◽  
Field Studies ◽  
Model Organisms ◽  
Protein Abundance ◽  
Molecular Systems ◽  
Functional Roles ◽  
Freshwater Spring ◽  
Abundance Variation ◽  
Plastic Responses

AbstractIdentifying when and where environmental change induces molecular responses in natural populations is an important goal in contemporary ecology. It can aid in identifying molecular signatures of populations experiencing stressful conditions and potentially inform if species are approaching the limits of their tolerance niches. Achieving this goal is hampered by our limited understanding of the influence of environmental variation on the molecular systems of most ecologically relevant species as the pathways underlying fitness-affecting plastic responses have primarily been studied in model organisms under controlled laboratory conditions. In this study, we establish relationships between protein abundance patterns and the abiotic environment by profiling the proteomes of 24 natural populations of the caddisfly Crunoecia irrorata. We subsequently relate these profiles to natural variations in the abiotic characteristics of their freshwater spring habitats which shows that protein abundances and networks respond to abiotic variation according to the functional roles these proteins have. We provide evidence that geographic and past and present environmental differences between sites affect protein abundances and identifications, and that baseline reaction norms are ubiquitous and can be used as information rather than noise in comparative field studies. Taking this natural variation into account is a prerequisite if we are to identify the effects environmental change has on natural populations.

The Biology of Aging in Insects: From Drosophila to Other Insects and Back

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Daniel E.L. Promislow ◽  
Thomas Flatt ◽  
Russell Bonduriansky
Keyword(s):  
Drosophila Melanogaster ◽  
Molecular Model ◽  
Natural Populations ◽  
Field Studies ◽  
Model System ◽  
Annual Review ◽  
Publication Date ◽  
Diverse Species ◽  
Enormous Amount ◽  
Biology Of Aging

An enormous amount of work has been done on aging in Drosophila melanogaster, a classical genetic and molecular model system, but also in numerous other insects. However, these two extensive bodies of work remain poorly integrated to date. Studies in Drosophila often explore genetic, developmental, physiological, and nutrition-related aspects of aging in the lab, while studies in other insects often explore ecological, social, and somatic aspects of aging in both lab and natural populations. Alongside exciting genomic and molecular research advances in aging in Drosophila, many new studies have also been published on aging in various other insects, including studies on aging in natural populations of diverse species. However, no broad synthesis of these largely separate bodies of work has been attempted. In this review, we endeavor to synthesize these two semi-independent literatures to facilitate collaboration and foster the exchange of ideas and research tools. While lab studies of Drosophila have illuminated many fundamental aspects of senescence, the stunning diversity of aging patterns among insects, especially in the context of their rich ecology, remains vastly understudied. Coupled with field studies and novel, more easily applicable molecular methods, this represents a major opportunity for deepening our understanding of the biology of aging in insects and beyond. Expected final online publication date for the Annual Review of Entomology, Volume 67 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

The relationship between Pseudodiplorchis americanus (Monogenea) density and host resources under controlled environmental conditions

Parasitology ◽  
1994 ◽  
Vol 108 (2) ◽  
pp. 175-183 ◽  
Author(s):  
K. Tocque ◽  
R. C. Tinsley
Keyword(s):  
Fat Body ◽  
Good Condition ◽  
Natural Populations ◽  
Field Studies ◽  
Temperature Cycle ◽  
Large Individual ◽  
Large Variability ◽  
Density Dependent ◽  
Feeding Efficiency ◽  
Field Samples

SUMMARYA previous study has shown that, under natural conditions, energy reserves of the desert toad, Scaphiopus couchii, are negatively related to the density of infection by Pseudodiplorchis americanus. However, this was based predominantly on collections of active animals from breeding congregations and inevitably selected toads which were in good condition. The parasite, a blood-feeding monogenean, occurs in burdens of up to 30 worms/host (mean intensity 6 worms/host) and represents a significant drain on reserves because the host does not feed during a 10-month hibernation. Field studies cannot resolve the possibility that larger worm densities are not observed in nature due to parasite-induced host mortality. The present study was conducted during investigations of P. americanus development and survival under controlled laboratory conditions, utilizing experimentally infected hosts which created worm densities larger than those observed in natural populations. At all temperature regimes, infected animals had smaller fat bodies than those uninfected but differences were generally not statistically significant due to large individual variations, presumably resulting from variations in past feeding efficiency. At cool temperatures (15–20 °C) there was no density-dependent effect on host fat body weight, and at a diurnal temperature cycle of 20–34 °C (simulating that experienced by host and parasite during the summer months), the effects of high temperatures were greater than the effects of infection, due to increased toad metabolic rates. The most significant effects of P. americanus were observed in hosts that began hibernation in relatively poor condition and experienced moderate temperatures (25 °C) during hibernation. The toads generally maintained packed blood cell levels (PCV) levels even when fat body weights were low, but infected animals had a lower PCV irrespective of fat body levels. In animals unfed after field collection, PCV was reduced in uninfected toads and was even lower in infected animals. Although very heavily infected toads (burdens of 35–95 worms/host) were generally in poorer condition than uninfected toads they still survived long-term hibernation under extreme nutritional stress. This study therefore confirmed observations made in field studies that there is a density-dependent relationship between the hosts' survival prospects and P. americanus infection. However, given the large variability in feeding efficiency and stored resources between individual toads, there is no evidence that the most heavily infected toads would have been unrepresented in field samples due to parasite-induced mortality.

The effects of obstacle size on periodic travelling waves in oscillatory reaction–diffusion equations

2007 ◽  
Vol 464 (2090) ◽  
pp. 365-390 ◽  
Author(s):  
Matthew J Smith ◽  
Jonathan A Sherratt ◽  
Nicola J Armstrong
Keyword(s):  
Large Scale ◽  
Order Approximation ◽  
Travelling Waves ◽  
Natural Populations ◽  
Reaction Diffusion ◽  
Field Studies ◽  
Reaction Diffusion Equations ◽  
Infinite Domain ◽  
Predator Prey ◽  
Predator Prey Model

Many natural populations undergo multi-year cycles, and field studies have shown that these can be organized into periodic travelling waves (PTWs). Mathematical studies have shown that large-scale landscape obstacles represent a natural mechanism for wave generation. Here, we investigate how the amplitude and wavelength of the selected waves depend on the obstacle size. We firstly consider a large circular obstacle in an infinite domain for a reaction–diffusion system of ‘ λ – ω ’ type. We use perturbation theory to derive a leading order approximation to the wave generated by the obstacle. This shows the dependence of the wave properties on both parameter values and obstacle size. We find that the limiting values of the amplitude and wavelength are approached algebraically with distance from the obstacle edge, rather than exponentially in the case of a flat boundary. We use our results to predict the properties of waves generated by a large circular obstacle for an oscillatory predator–prey system, via a reduction of the predator–prey model to normal form close to Hopf bifurcation. Our predictions compare well with numerical simulations. We also discuss the implications of these results for wave stability and briefly investigate the effects of obstacles with elliptical geometries.

Field studies with thiophanate given as a 14-day low level in-feed anthelmintic to pigs

1979 ◽  
Vol 105 (4) ◽  
pp. 81-82 ◽  
Author(s):  
D. Baines ◽  
P. Evans ◽  
P. Lake ◽  
D. Frape
Keyword(s):  
Field Studies ◽  
Low Level
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