The reproductive strategy of the gregarious parasitoid, Pteromalus puparum (Hymenoptera: Pteromalidae) : 1. Optimal number of eggs in a single host.

abstract：:Mature growth-phase internodes of Alaska paper birch (Betula resinifera) are preferred by the snowshoe hare (Lepus americanus) over juvenile growth-phase internodes due to the low food value of the latter. While the mature over juvenile preferencec cannot be explained by the levels of inorganic nutrients or gross chem...

journal_title：Oecologia

authors： Reichardt PB,Bryant JP,Clausen TP,Wieland GD

更新日期：1984-12-01 00:00:00

abstract：:Adaptations to aridity of the reedfrog Hyperolius viridiflavus nitidulus, living in different parts of the season-ally very dry and hot West African savanna, are investigated. 1. During the dry season mainly juveniles (weighing 200-600 mg) were found in the field. A very low rate of evaporative water loss (EWL; about ...

journal_title：Oecologia

authors： Geise W,Linsenmair KE

更新日期：1986-03-01 00:00:00

abstract：:The natural geographical occurrence, carbon assimilation, and structural and biochemical diversity of species with C4 photosynthesis in the vegetation of Mongolia was studied. The Mongolian flora was screened for C4 plants by using 13C/12C isotope fractionation, determining the early products of 14CO2 fixation, micros...

journal_title：Oecologia

authors： Pyankov VI,Gunin PD,Tsoog S,Black CC

更新日期：2000-04-01 00:00:00

abstract：:Some perennial fugitive plants that colonize badger disturbances in xeric prairies have a limited dispersal capacity, and consequently propagules are dispersed over a small area. I hypothesized that high density-dependent mortality might occur early in the life history of such species, and thus increased survival migh...

journal_title：Oecologia

authors： Platt WJ

更新日期：1976-12-01 00:00:00

abstract：:Seasonal changes in the photosynthetic characteristics of intact involucral leaves of Anemone raddeana were investigated under laboratory conditions. Net photosynthesis and constant water vapor pressure deficit showed almost the same seasonal trend. They increased rapidly from mid-April immediately after unfolding of ...

journal_title：Oecologia

authors： Yoshie F,Yoshida S

更新日期：1987-05-01 00:00:00

abstract：:We studied the nutritional behaviour of hinds foraging on a mixed-forest edge by direct observation of their choices at each season and by measuring nutrient concentration in the plants. We compared nutrient concentrations in the observed diets with those in the total available vegetation, and with those of 1,000 rand...

journal_title：Oecologia

authors： Verheyden-Tixier H,Renaud PC,Morellet N,Jamot J,Besle JM,Dumont B

更新日期：2008-06-01 00:00:00

abstract：:Prey subsidies originating from detritus add nutrients and energy to arboreal communities. Measurement of this subsidy is required in the understanding of how food web dynamics respond to changes in surrounding environments. Shrub spiders are one of the key predators involved in food web coupling. We evaluate the effe...

journal_title：Oecologia

authors： Haraguchi TF,Uchida M,Shibata Y,Tayasu I

更新日期：2013-04-01 00:00:00

abstract：:Analysis of the degree of order in species assemblages in terms of nested subsets has received increased interest during the last decade. However, recently a series of papers have questioned the validity of methods employed for testing whether observed patterns deviate from random expectations. The current view seems ...

journal_title：Oecologia

authors： Jonsson BG

更新日期：2001-05-01 00:00:00

abstract：:Theoretical models about the benefits of philopatry predict that immigrant fitness can be higher, lower or similar to that of philopatrics depending on habitat heterogeneity, dispersal costs, distance between patches or population densities. In this study, we compared transience rates, local survival and recruitment a...

journal_title：Oecologia

authors： Oro D,Tavecchia G,Genovart M

更新日期：2011-04-01 00:00:00

abstract：:Difficulties in using genetic markers to demonstrate that changes in gene frequency cause fluctuations in the density of animal populations are illustrated. The frequency of chicks with light-coloured down increased during 4 years when population density of red grouse declined and the inherent level of aggressive beha...

journal_title：Oecologia

authors： Moss R,Watson A

更新日期：1987-10-01 00:00:00

abstract：:The habitats occupied by species of wood warblers (Emberizidae) were compared at two study areas, Itasca State Park, Minnesota and Mount Blue State Park, Maine. Univariate comparisons of each variable of habitat structure show geographic differences for each species of warbler. Habitats available were also different b...

journal_title：Oecologia

authors： Collins SL

更新日期：1983-09-01 00:00:00

abstract：:Climate change is driving species range shifts worldwide. However, physiological responses related to distributional changes are not fully understood. Oceanographers have reported an increase in ocean temperature in the northwest Iberian Peninsula that is potentially related to the decline in some cold-temperate inter...

journal_title：Oecologia

authors： Martínez B,Arenas F,Rubal M,Burgués S,Esteban R,García-Plazaola I,Figueroa FL,Pereira R,Saldaña L,Sousa-Pinto I,Trilla A,Viejo RM

更新日期：2012-10-01 00:00:00

abstract：:Foragers of the leafcutting ant, Atta cephalotes L. (Formicidae, Attini) seldom or never attack many of the plant species available to them in nature. In the semideciduous forests of lowland Guanacaste Province, Costa Rica, one of the tree species seldom cut is Hymenaea courbaril L. (Leguminosae, Caesalpinioideae). We...

journal_title：Oecologia

authors： Hubbell SP,Wiemer DF,Adejare A

更新日期：1983-12-01 00:00:00

abstract：:We determined the effects of defoliation by a graminivorous grasshopper on the foliage quality of the C3 plant, western wheatgrass (Pascopyrum smithii [Rydb] A. Love). Additionally, we determined the effects of this defoliation upon the subsequent feeding of the graminivorous grasshopper Phoetaliotes nebrascensis Thom...

journal_title：Oecologia

authors： Redak RA,Capinera JL

更新日期：1994-11-01 00:00:00

abstract：:Resprouting is the main regeneration mechanism after fire in Mediterranean-type ecosystems. Herbivores play an important role in controlling postfire seedling establishment, but their influence on regeneration by resprouting is less well known. To study the effects of fire intensity on resprouting of Adenostoma fascic...

journal_title：Oecologia

authors： Moreno JM,Oechel WC

更新日期：1991-01-01 00:00:00

abstract：:There are three major components to plant structure relevant to searching parasitoids: 1) plant size or surface area, 2) the variation among plant parts (structural heterogeneity), such as seed heads, flowers and nectaries, and heterogeneous surfaces (e.g. glabrous, hirsute), and 3) the connectivity of parts or plant ...

journal_title：Oecologia

authors： Andow DA,Prokrym DR

更新日期：1990-02-01 00:00:00

abstract：:Models of the evolution of seed dormancy reveal that dormancy is favoured either when opportunities for establishment vary over time and when there is wide variation in the probability of success, or when the probability of success is limited by frequency dependence. Empirical evidence supporting the temporal heteroge...

journal_title：Oecologia

authors： Zammit C,Zedler PH

更新日期：1990-08-01 00:00:00

abstract：:In this review I offer a solution to the problem why endotherm populations appear to be so inefficient in converting food energy into body substance despite the fact that individual endotherms are just as 'efficient' in this respect as individual ectotherms. Calculated for individuals of half the adult mass both ectot...

journal_title：Oecologia

authors： Wieser W

更新日期：1985-07-01 00:00:00

abstract：:Severe droughts may alter the reproductive phenology of tropical tree species, but our understanding of these effects has been hampered by confounded variation in drought, light and other factors during natural drought events. We used a large-scale experimental reduction of throughfall in an eastern-central Amazon for...

journal_title：Oecologia

authors： Brando P,Ray D,Nepstad D,Cardinot G,Curran LM,Oliveira R

更新日期：2006-11-01 00:00:00

abstract：:We have analysed the importance of worker ants (Proformica longiseta, Formicidae) as pollinators of a mass-flowering woody plant (Hormathophylla spinosa, Cruciferae) in the high-mountain area of the Sierra Nevada (southern Spain). We have quantified the abundance and foraging behavior of P. longiseta in comparison wit...

journal_title：Oecologia

authors： Gómez JM,Zamora R

更新日期：1992-09-01 00:00:00

abstract：:Mortality estimates for the immature stages of two butterfly species, Danaus plexippus and D. chrysippus, were obtained by observing the survival of egg cohorts on different sized patches of food plants (Asclepias spp.), over a one-year period. Losses were variable (0-100%) but usually high (90% and over) throughout t...

journal_title：Oecologia

authors： Zalucki MP,Kitching RL

更新日期：1982-01-01 00:00:00

abstract：:Growth and respiration were measured in a species of Anonchus (Nematoda: Plectidae) at 5°C, 10°C, 15°C, 20°C and 25°C. At 5°C no growth was measurable but the organisms remained active. Maximum production occurred at 15°C, but the highest rate of growth occurred at 20°C. Thus, adult size attained is dependent on the t...

journal_title：Oecologia

authors： Laybourn J

更新日期：1979-08-01 00:00:00

abstract：:The effects of competitive suppression by vines on the non-vine plant community have received little attention in temperate habitats. This study investigated the impact vines have on their herbaceous hosts in a wetland community at two soil fertility levels. Plots in an oligohaline marsh were treated in a 2 × 2 factor...

journal_title：Oecologia

authors： Gough L,Grace JB

更新日期：1997-10-01 00:00:00

abstract：:The patterns of flower visitation by lizards (Podarcis lilfordi, Lacertidae) and insects (mainly flies, bees and wasps) on the shrub Euphorbia dendroides, were studied in the island of Cabrera (Balearic Islands) during the flowering seasons of 1995 and 1996. Lizards act as true pollinators of the plant, moving large q...

journal_title：Oecologia

authors： Traveset A,Sáez E

更新日期：1997-07-01 00:00:00

abstract：:The great majority of Eucalyptus spp. are facultative resprouters, and they dominate the eucalypt forests of Australia. Despite this numeric and geographic dominance, there is a general lack of knowledge of their capacity for carbon capture and water loss during canopy reinstation. After a crown-removing fire, we meas...

journal_title：Oecologia

authors： Turnbull TL,Buckley TN,Barlow AM,Adams MA

更新日期：2014-10-01 00:00:00

abstract：:The δ 13C, ‰ values of the two principal, widely distributed CAM species in Big Bend National Park, Texas, were examined and related to phytosociologic and macroclimatic parameters. Samples of Agave lecheguilla and Opuntia engelmannii were collected along an elevational gradient covering 1370 m, and δ values for both ...

journal_title：Oecologia

authors： Eickmeier WG,Bender MM

更新日期：1976-12-01 00:00:00

abstract：:At Bakers Hill, differential winter mortality of juvenile slowgrowing Amphibolurus ornatus is correlated with the incidence of frosts (Bradshaw, 1971). The present study shows that the probability an individual will spend the night in a refuge that is safe from the lethal effect of a frost is directly related to the i...

journal_title：Oecologia

authors： Baverstock PR

更新日期：1978-01-01 00:00:00

abstract：:The seasonal changes in plant community architecture and its importance to insect herbivores during the ruderal-early stages of an experimental secondary successional gradient are described. The dominant group of insect herbivores, the Auchenorrhyncha (Hemiptera: Homoptera) are considered together with their host plan...

journal_title：Oecologia

authors： Stinson CS,Brown VK

更新日期：1983-01-01 00:00:00

abstract：:For a symbiosis to be a mutualism, benefits received must exceed costs incurred for both partners. Partners can prevent costly overexploitation through behaviors that moderate interactions with the other symbiont. In a symbiosis between crayfish and branchiobdellidan annelids, the worms can increase crayfish survival ...

journal_title：Oecologia

authors： Farrell KJ,Creed RP,Brown BL

更新日期：2014-02-01 00:00:00

abstract：:Male dragonflies of the species Aeschna cyanea pay several visits per day to a suitable pond in search of mates. The influence of the population density upon the daily duration of presence of single dragonfly males was investigated by means of multiple regression analysis. Several environmental factors were also consi...

journal_title：Oecologia

authors： Kaiser H

更新日期：1974-12-01 00:00:00