scholarly journals Movement away from feeding site of the aphid Sitobion αvenαe (F.) (Hemiptera: Aphididae) when parasitized by Aphelinus αbdominαlis (Dalman) (Hymenoptera: Aphelinidae)

2017 ◽  
Vol 1 ◽  
pp. 59 ◽  
Author(s):  
D.Ρ. Lykouressis ◽  
Η.F. Υan Emden

The aphid Sitobion avenae (F.), parasitized by Aphelinus abdominalis (Dalman), tends to leave either the feeding sites gathering in particular parts of its host-plant or even the host-plant. This behavior partially explains the phenomenon of reduced parasitism contribution to the overall mortality in several aphid population studies as interpreted by Hughes’ method.

2019 ◽  
Author(s):  
M D Mahbubur Rahman ◽  
Myron P Zalucki ◽  
Michael J Furlong

Abstract The impact of simulated rainfall on diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), larvae depends on their stage-specific feeding behavior, physical characteristics, and host plants. Neonates released at typical oviposition sites on Chinese cabbage (Brassica rapa var. pekinensis L. [Brassicales: Brassicaceae]) plants moved less (3–72 cm) and spend shorter periods (>1 h) than it has been previously reported for common cabbage (Brassica oleracea var. capitata L. [Brassicales: Brassicaceae]) (>80 cm and >3 h, respectively) before establishing feeding sites. On both host plants, larvae spent longer on the abaxial surfaces of leaves and were more likely to establish mines there than on the adaxial surfaces. On Chinese cabbage plants, ≈40% of neonates were removed when exposed to rainfall (5.6 cm/h for 3 min) within 5 min of release. Larval losses decreased rapidly as the interval between release and rainfall exposure increased and exposure to rainfall 2 h after release did not affect survival. On common cabbage plants, ≈65% of neonates were removed when exposed to rainfall within 30 min of release, losses decreased as the interval between release and rainfall exposure increased, but they decreased more slowly than on Chinese cabbage, and rainfall caused significant larval mortality up to 4 h after release. Rainfall also affected later instar larvae (susceptibility: 2nd> 3rd = 4th) but neither the susceptibility of these larvae nor that of pupae was affected by the host plant. Wet leaf surfaces disrupted movement and feeding site establishment by neonates. When dislodged from plants on to the surface of wet soil, most later stage larvae could relocate host plants, but most neonates could not.


Animals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2088
Author(s):  
Federico Ossi ◽  
Nathan Ranc ◽  
Paul Moorcroft ◽  
Priscilla Bonanni ◽  
Francesca Cagnacci

Winter supplemental feeding of ungulates potentially alters their use of resources and ecological interactions, yet relatively little is known about the patterns of feeding sites use by target populations. We used camera traps to continuously monitor winter and spring feeding site use in a roe deer population living in a peri-urban area in Northern Italy. We combined circular statistics with generalized additive and linear mixed models to analyze the diel and seasonal pattern of roe deer visits to feeding sites, and the behavioral drivers influencing visit duration. Roe deer visits peaked at dawn and dusk, and decreased from winter to spring when vegetation regrows and temperature increases. Roe deer mostly visited feeding sites solitarily; when this was not the case, they stayed longer at the site, especially when conspecifics were eating, but maintained a bimodal diel pattern of visits. These results support an opportunistic use of feeding sites, following seasonal cycles and the roe deer circadian clock. Yet, the attractiveness of these artificial resources has the potential to alter intra-specific relationships, as competition for their use induces gatherings and may extend the contact time between individuals, with potential behavioral and epidemiological consequences.


The Auk ◽  
1983 ◽  
Vol 100 (3) ◽  
pp. 711-716 ◽  
Author(s):  
Dale L. Rabe ◽  
Harold H. Prince ◽  
Donald L. Beaver

Abstract Live-trapped, adult American Woodcock (Scolopax minor) were tested in a series of laboratory experiments designed to evaluate the role of soil as a proximal cue for selecting feeding sites and to investigate foraging strategies for capturing earthworms (Lumbricidae). Foraging trials were conducted in a circular arena and showed that color, which tends to be correlated with the soil types and moisture regimes preferred by earthworms, was an important proximal cue for selecting feeding sites. Woodcock captured earthworms most efficiently in areas of relatively high prey density, because they used a nonrandom search pattern following an initial capture.


Nematology ◽  
2003 ◽  
Vol 5 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Pablo Castillo ◽  
Nicola Vovlas ◽  
Alberto Troccoli

Abstract Severe root infection of wild olive (Olea europea L. ssp. sylvestris), together with heavy soil infestation by the reniform nematode Rotylenchulus macrosoma, was detected in a natural wild olive orchard on sandy soil in Cádiz province, Andalucía, southern Spain. Most, but not all, of the morphometric characters of this population agreed with those reported for immature and adult females and males in previously studied populations. Sedentary immature and mature females showed a semi-endoparasitic feeding habit in wild and cultivated olives (cvs Arbequina and Picual). Naturally infected roots of wild olive responded to nematode infection identically to artificially infected olive planting stocks. The feeding site induced by R. macrosoma on olive roots consists of a stelar syncytium, which originates from an endodermal cell enlarging by a curved sheet of pericycle cells formed by hypertrophy of pericycle cells adjacent to the feeding cell. There were obvious anatomical differences between the feeding sites induced by R. macrosoma and R. macrodoratus on olive roots.


2015 ◽  
Vol 55 (3) ◽  
pp. 298 ◽  
Author(s):  
Derek W. Bailey ◽  
Mitchell B. Stephenson ◽  
Marco Pittarello

Feeding site selection is a critical part of livestock foraging that can constrain and/or increase the choices available during diet selection. When livestock choose new feeding sites, vegetation and nutrient profiles can differ from other areas, especially in heterogeneous environments with rugged terrain. Correspondingly, livestock should remain longer in feeding sites in rugged heterogeneous pastures than in homogeneous pastures where animals may alternate among feeding sites to facilitate diet mixing and to prevent satiation. The objective of this study was evaluate how terrain and corresponding heterogeneity may affect the sequence and pattern of feeding site selection of free-roaming livestock. Grazing patterns of mature cows were evaluated on six ranches located in Arizona, Montana and New Mexico. In total, 11–19 cows were tracked for 1–3-month periods at each ranch by using global positioning system (GPS) collars. Positions were recorded at 10- or 15-min intervals and used to identify where cows grazed during the early morning (0500 hours to 1000 hours). Pastures (336–9740 ha) at each ranch were divided into seven to nine sections (48–1082 ha) as an indicator of feeding sites. Classification was based on cattle density and topographical and vegetation types. Sequences of daily section selection were evaluated using transition matrixes. For all ranches, the sequence of section selection differed from what would be expected by chance, indicating that the section selected on the following day depended on the section selected on the previous day. For ranches with relatively gentle terrain, cattle selected different feeding sites ~70% of the tracking period. In contrast, cows at the ranch with the largest pasture and enclosing both mountainous and gentle terrain stayed in the same feeding site for over 10 successive days for 42% of the tracking period. Smaller pastures with only mountainous terrain were intermediate. Cows grazing gentle topography and relatively homogeneous vegetation alternated among feeding sites (sections in the present study) more frequently than cows grazing pastures with more rugged topography and more heterogeneous vegetation. This pattern could help livestock mix forages and select a more diverse diet.


2005 ◽  
Vol 95 (4) ◽  
pp. 368-375 ◽  
Author(s):  
Nicola Vovlas ◽  
Hava F. Rapoport ◽  
Rafael M. Jiménez Díaz ◽  
Pablo Castillo

Root-knot nematodes (Meloidogyne spp.) are sedentary, obligate endoparasites in plants, where they induce specialized feeding sites. The feeding sites act as strong metabolic sinks to which photosynthates are mobilized. The histopathological modifications in the nematode-induced feeding sites of artificially inoculated chickpea cv. UC 27 were qualitatively and quantitatively compared using five isolates of M. artiellia and one isolate each of M. arenaria, M. incognita, and M. javanica. All Meloidogyne isolates infected chickpea plants, but root gall thickening was significantly less for M. artiellia isolates than for the other Meloidogyne species. Nevertheless, neither the number of giant cells in the feeding site (averaging four to six) nor the area of individual giant cells was influenced by nematode species or isolate. However, the number of nuclei per giant cell was significantly smaller, and the maximum diameters of nuclei and nucleoli were significantly greater, in giant cells induced by M. artiellia isolates than in those induced by M. arenaria, M. incognita, or M. javanica. In a second experiment, M. artiellia-induced giant cells in faba bean and rapeseed also contained a small number of large nuclei.


2021 ◽  
Author(s):  
◽  
Robin Alexander Fordham

<p>An account is given of ecological studies on the Southern Black-backed Gull Larus dominicanus Licht in which attention is directed to the structure and balance of the Wellington population. This population is large; in the 1963-64 season more than 5,600 pairs were breeding in the study area, and the peak non-breeding season population in 1964 exceeded 12,000 birds. Its growth has been closely associated with the increase of the human population, and the present distribution and dispersal of gulls is strongly influenced by the distribution of " artificial" feeding sites such as refuse tips and meatworks. The population is composed of breeding colonies, night roosting flocks and daily communal flocks which are inter-related by the social activities and dispersal of the birds. Thus the population is more or less integrated, rather than simply comprising discrete geographic units. Seasonal fluctuations in size and age composition of communal flocks are discussed. Breeding success varies between colonies. It is affected by mammalian predation in some, and by drowning in others, while the largest colonies are comparatively safe for breeding birds. The rapid growth of the whole population in the last five to 10 years appears to have some influence on nesting density, clutch size, spread of laying and overall breeding success. In recent years production of young has been twice that required to maintain the population which has grown at the rate of not less than 7.2% annually. Mortality of banded gulls inside and outside the colony is described and the influence of several factors on chick mortality examined. The principal factor limiting the population appears to be the food supply in relation to the number of birds. When numbers increase and the food supply diminishes, major regulation of the population is apparently achieved in the colony by predation (but not cannibalism) of young by adults. Dispersal of banded gulls from the Wellington colonies is very restricted.</p>


Rangifer ◽  
2000 ◽  
Vol 20 (5) ◽  
pp. 158 ◽  
Author(s):  
Chris J. Johnson ◽  
Katherine L. Parker ◽  
Douglas C. Heard

We examined the foraging habits of the northern woodland caribou ecotype {Rangifer tarandus caribou) at the scale of the individual feeding site. Field data were collected in north-central British Columbia over two winters (Dec 1996-Apr 1998). We trailed caribou and measured vegetation characteristics (species composition and percent cover), snow conditions (depth, density, and hardness), and canopy closure at terrestrial and arboreal feeding sites, and at random sites where feeding had not occurred. Logistic regression was used to determine the attributes of feeding sites that were important to predicting fine scale habitat selection in forested and alpine areas. In the forest, caribou selected feeding sites that had a greater percent cover of Cladina mitis and Cladonia spp, lower snow depths, and a lower percentage of debris and moss. Biomass of Bryoria spp. at the 1-2 m stratum above the snow significantly contributed to predicting what trees caribou chose as arboreal feeding sites. In the alpine, caribou selected feeding sites with a greater percent cover of Cladina mitis, Cladina rangiferina, Cetraria cucullata, Cetraria nivalis, Thamnolia spp., and Stereocaulon alpinum as well as lower snow depths.


Author(s):  
Angélica Miamoto ◽  
Andressa Cristina Zamboni Machado ◽  
Orazília França Dorigo ◽  
Thaísa Muriel Mioranza ◽  
Heriksen Higashi Puerari ◽  
...  

Root-knot nematodes are obligate parasites, so changes at their feeding sites can limit their development. Alterations to feeding sites is one of the main actions taken by antagonistic plants. The aim of this study was to assess the response and histopathology of interactions between Meloidogyne javanica and the roots of Macrotyloma axillare cv. Java. The penetration and development of the nematode was assessed from 8 to 30 days after inoculation (DAI) with 3000 eggs + second-stage juveniles (J2) of M. javanica. The reproduction factor (RF) was assessed at 60 DAI, with two inoculation levels, 700 and 1000 eggs + J2, and the changes in the development and histopathology of M. javanica was assessed at 10, 15 and 30 DAI. Suscetible soybean was used as a control. The development of nematodes at the third (J3) and fourth juvenile (J4) stages was delay, despite the presence of J2 inside the roots, and no adult females were found in the M. axillare cv. Java roots. RF was 0.31 and 0.39 for M. axillare cv. Java and 3.40 and 4.52 for soybean at inoculation levels of 700 and 1000 eggs + J2, respectively. The feed cells in M. axillare cv. Java could not effectively nourish the nematode, which led to deformed females 30 DAI. The feed cells and nematode development, however, were normal in soybean. M. axillare cv. Java was resistant to M. javanica and had an antagonistic potential, because it did not prevent the nematode from penetrating the roots but had a negative effect on M. javanica due to the inefficiency of the feeding site.


Genetics ◽  
2019 ◽  
Vol 211 (4) ◽  
pp. 1409-1427 ◽  
Author(s):  
Nicky Wybouw ◽  
Olivia Kosterlitz ◽  
Andre H. Kurlovs ◽  
Sabina Bajda ◽  
Robert Greenhalgh ◽  
...  

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