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531.
Julie?A.?TeichroebEmail author Pascale?Sicotte 《Behavioral ecology and sociobiology》2012,66(3):453-466
Vigilance often decreases with increasing group size, due to lower predation risk or greater scramble competition for food.
A group size effect on vigilance is seldom seen in primates, perhaps because scanning and feeding often occur simultaneously
or because the distinction between routine and induced vigilance has not been investigated. We analyzed feeding and resting
observations separately while distinguishing between routine and induced scans in four groups of wild ursine colobus monkeys
(Colobus vellerosus) experiencing scramble competition for food and infanticide risk. We used linear mixed-effect models to test the effect of
group size, age–sex class, number of neighbors, number of adult male neighbors, and height in the canopy on scanning rates
(vigilance) with and without evident conspecific threat. Food type was also examined in the feeding models. Perceived predation
risk affected vigilance more than scramble competition for food and infanticide risk. Routine and induced vigilance were greatest
at lower canopy heights during feeding and resting and increased when individuals had fewer neighbors while resting. A group
size effect was found on induced vigilance while resting, but scanning increased with group size, which probably indicates
visual monitoring of conspecifics. Scanning rates decreased while feeding on foods that required extensive manipulation. This
supports the idea that vigilance is relatively cost free for upright feeders when eating food that requires little manipulation,
a common feature of folivore diets. In the presence of threatening conspecific males, close proximity to resident males decreased
individual vigilance, demonstrating the defensive role of these males in the group. 相似文献
532.
Virginia?Gonzalez-JimenaEmail author Patrick?S.?Fitze 《Behavioral ecology and sociobiology》2012,66(2):305-315
Glucocorticoids affect physiology and behaviour, reproduction and potentially sexual selection as well. Short-term and moderate
glucocorticoid elevations are suggested to be adaptive, and prolonged and high elevations may be extremely harmful. This suggests
that optimal reproductive strategies, and thus sexual selection, may be dose dependent. Here, we investigate effects of moderate
and high elevations of blood corticosterone levels on intra- and intersexual behaviour and mating success of male common lizards
Lacerta vivipara. Females showed less interest and more aggressive behaviour towards high corticosterone males and blood corticosterone levels
affected male reproductive strategy. Males of moderate and high corticosterone elevations, compared with Control males, showed
increased interest (i.e., higher number of chases, tongue extrusions, and approaches) towards females and high corticosterone
males initiated more copulation attempts. However, neither increased male interest nor increased copulation attempts resulted
in more copulations. This provides evidence for a best-of-a-bad-job strategy, where males with higher corticosterone levels
compensated for reduced female interest and increased aggressive female behaviour directed towards them, by showing higher
interest and by conducting more copulation attempts. Blood corticosterone levels affected intrasexual selection as well since
moderate corticosterone levels positively affected male dominance, but dominance did not affect mating success. These findings
underline the importance of female mate choice and are in line with adaptive compensatory behaviours of males. They further
show that glucocorticoid effects on behaviour are dose dependent and that they have important implications for sexual selection
and social interactions, and might potentially affect Darwinian fitness. 相似文献
533.
Francisco?Santiago-QuesadaEmail author José?A.?Masero Sora?M.?Estrella Juan?M.?Sánchez-Guzmán 《Behavioral ecology and sociobiology》2012,66(3):397-405
There is a large literature dealing with daily foraging routines of wild birds during the non-breeding season. While different
laboratory studies have showed that some bird activity patterns are a persistent property of the circadian system, most of
field studies preclude the potential role of an endogenous circadian rhythm in controlling bird’s foraging routines. In this
study we compared the patterns of diurnal foraging activity and intake rates of migrating black-tailed godwits, Limosa limosa (radio-tagged and non-tagged individuals) at two stopover sites (habitats) with different environmental characteristics,
aiming at identifying proximate factors of bird activity routines. To gain insights into the role of food availability in
control of such foraging routines, we also estimated foraging activity patterns in captive godwits subjected to constant food
availability. Captive and wild black-tailed godwits showed a persistent bimodal activity pattern through daylight period.
Food availability had a significant effect on the intake rates, but had a subtler effect on foraging and intake rate rhythms.
Temperature and wind speed (combined in a weather index) showed non-significant effects on both rhythms. Although we could
not discard a role for natural diurnal changes in light intensity, an important timing cue, our findings support the idea
that an endogenous circadian rhythm could be an important proximate factor regulating foraging activity and food items taken
per unit time of wild black-tailed godwits during migration. 相似文献
534.
Kirsten?Kreuter Elfi?Bunk Anna?Lückemeyer Robert?Twele Wittko?Francke Manfred?AyasseEmail author 《Behavioral ecology and sociobiology》2012,66(3):475-486
Social parasitism is widespread in many groups of social living hymenopteran species and has also evolved in the genus Bombus. Cuckoo bumblebees (subgenus Psithyrus) are obligate brood parasites in nests of other bumblebee species. After nest usurpation and the killing of the host queen,
the parasite female has to control worker reproduction in order to accomplish and maintain reproductive dominance and to ensure
her reproductive success. The aim of our study was to examine whether the generalist parasitic bumblebee Bombus bohemicus monopolizes and prevents worker reproduction by physical or chemical means and to identify possible odor compounds involved
therein. We performed bioassays with callow workers of the host Bombus terrestris and have shown that B. bohemicus females are able to suppress host worker ovarian development, when these host workers are under the direct influence of the
parasite female. Furthermore, by chemical analyses, we have demonstrated that the parasite females adjust to the odor profiles
of their host queens in order to maintain the level of fertility signaling inside the host colony although the host queen
is absent. We also found that host workers change their odor profile after nest usurpation by the parasite female and consequently,
we suggest that the host and parasite are caught up in a chemical arms race. 相似文献
535.
A prominent interaction in the lives of social mammals is allogrooming. Individuals allogroom strategically and preferentially,
grooming high-quality individuals that control access to resources. This results in distinct patterns of allogrooming within
social groups, such that some individuals are groomed more than the others, some dyads express symmetry in allogrooming, and
others exchange allogrooming for other benefits. Allopreening, the avian equivalent of allogrooming, occurs commonly in group-living
birds, providing the opportunity to test whether social birds also use allopreening strategically in their social relationships.
I examined this hypothesis in family-living buff-breasted wrens (Cantorchilus leucotis) by examining allopreening initiation, reciprocation and rate during interactions involving breeding adults and offspring.
Buff-breasted wrens exhibit a nuclear family structure in which pairs display long-term partnerships, and juveniles delay
dispersing from natal territories for about 10 months. Allopreening was symmetrical between breeding partners: males and females
who initiated and reciprocated allopreening of partners with similar frequency, and within reciprocated bouts, allopreening
was time-matched. Pairs in which allopreening was not observed were more likely to divorce, but allopreening patterns did
not change in successive years of partnerships. Parent–offspring allopreening, by contrast, was asymmetrical in pattern; parents
initiated allopreening more than their offspring, and reciprocation never occurred. The different patterns of allopreening
observed within buff-breasted wren families suggest the strategic use of allopreening, possibly for the maintenance of long-term
partnerships and in exchange for social benefits from offspring. 相似文献
536.
Concei??o Juana Fortes óscar Ferreira Paulo A. Silva Theo Moura Rui Capit?o Luís Amante Michalis Vousdoukas Maria Bezerra 《Journal of Coastal Conservation》2012,16(4):461-472
In the framework of a research project entitled ??BRISA??BReaking waves and Induced SAnd transport??, a methodology was devised to characterize the waves joining together in-situ measurements and numerical wave propagation models. With this goal in mind, a number of in-situ measurements were made, for selected positions in front of Praia de Faro (South Portugal), during four days (25th to 28th March, 2009) by using different types of equipments (e.g., resistive wave gauges, pressure sensors, currentmeters and a new prototype pore pressure sensor using optical fibre). Wave records were obtained simultaneously offshore (at a water depth of 11.7?m below mean sea level, MSL) and at the surf and swash zones. The data processing and analysis were made by applying classical time domain techniques. Numerical simulations of the wave propagation between offshore and inshore for the measurement period were performed with two numerical models, a 1D model based on linear theory and a nonlinear Boussinesq-type model, COULWAVE, both forced by the measured offshore wave conditions of 27th March 2009. Comparisons between numerical results and field data for the pressure sensors placed in the surf and swash zones were made and discussed. This approach enables to evaluate the performance of those models to simulate those specific conditions, but also to validate the models by gaining confidence on their use in other conditions. 相似文献
537.
Portugal is strongly vulnerable to sea hazards due to intense vessel traffic and sea conditions. The southwest region off the Iberian Peninsula lies in the main route from the Mediterranean and Southern Hemisphere to the Northern Europe, causing a ship concentration in a narrow band off Cape S?o Vicente. Tankers represent a significant part of the vessel traffic and the occurrence of oil spills cannot be disregarded. Cape S?o Vicente region is part of a Natural Park with 110 Km of coastline, integrated in the European Natura 2000 network and its socio-economic context is closely related with sea resources exploitation, particularly fishing and tourism. Recognizing the importance of accurate information systems for the decision making process in an oil spill situation, this work presents the development of an integrated tool to support the process in the Algarve coast. The system relies in a regional operational mathematical model based on the MOHID modelling system. The system core is composed by three models (3D hydrodynamics, wave and Lagrangian transport) all linked in the same system and exchanging information in real time. Oil advection and weathering processes are coupled to the Lagragian transport model. The overall operational system includes external operational data products as inputs, to ensure a successful validation of the results. The system is linked to stakeholders and response authorities using a geographic referenced database based on Mapserver technology that will include relevant information for oil spill management. 相似文献
538.
Milan Novakovi? Muftah Mohamed Ali Ramadan Tatjana ?olevi? Knudsen Mali?a Anti? Vladimir Be?koski Gordana Gojgi?-Cvijovi? Miroslav M. Vrvi? Branimir Jovan?i?evi? 《Environmental Chemistry Letters》2012,10(3):287-294
Phenanthrene and methyl-phenanthrenes are major aromatic pollutants originating in particular from fuel oil. Phenanthrene is usually degraded faster than methyl-phenanthrenes under geological and environmental conditions. Here, we report a preferential and accelerated biodegradation of methyl-phenanthrenes versus phenanthrene in soil contaminated by fuel oil. The polluted soil was mixed with sawdust and sand to form a homogenized biopile. The biopile was continuously sprayed with microbial consortia isolated from crude oil?Ccontaminated soil and treated by biosurfactants and nutritive substances for biostimulation. During a 6-month bioremediation experiment, a steady increase in the relative abundance of phenanthrene compared to methyl-phenathrenes was observed by gas chromatography?Cmass spectrometry. The increase was the highest for trimethyl-phenanthrenes, with a phenanthrene/trimethyl-phenanthrenes ratio increasing from 0.42 to 2.45. By contrast, the control, non-stimulated samples showed a ratio decrease from 0.85 to 0.11. Moreover, the results showed that the level of degradability depends on the number of methyl groups. 相似文献
539.
Ivan Viegas Sónia Cotrim Marques Filipa Bessa Ana Lígia Primo Filipe Martinho Ulisses Miranda Azeiteiro Miguel ?ngelo Pardal 《Marine Biology》2012,159(1):33-43
This study provides a comprehensive examination of the life cycle dynamics of the brown shrimp (Crangon crangon L.) in the Mondego estuary, Portugal, a habitat located near the southern edge of the range of this species in European waters.
The phenology of all life stages was documented (from the occurrence of ovigerous females, developing embryos, planktonic
larvae and benthic post-larvae), and migration patterns of larvae into and out of the estuary were examined. Temperature-dependent
functions of egg and larval development were combined with data on field abundance to predict the timing and magnitude of
occurrence of larvae and recruits. Compared to brown shrimp at higher latitudes, southern conspecifics grow slower, mature
earlier and have smaller brood sizes, and larvae have a more protracted settlement period. The Mondego estuary, besides acting
as nursery area, is a dynamic platform for C. crangon to use in different stages, sizes and seasons. 相似文献
540.
Direct and indirect methods have been used to describe patterns of movement of fishes, but few studies have compared these
methods simultaneously. We used 20 years of trawl survey data and 1 year of acoustic telemetry data to evaluate the vertical
and horizontal movement patterns of spotted ratfish Hydrolagus colliei in Puget Sound, WA, USA. Densities of large ratfish (≥30 cm) were higher at the deepest depths trawled (70 m) during daylight
hours, whereas densities were similar across depth zones (to 10 m) at night. Acoustic tracking of ratfish showed distinct
diel patterns of movement and activity level; ratfish moved into shallow, nearshore habitats at night from deeper, offshore
habitats during the day and made ~3 times more moves at night than day in shallow habitats. Broader spatial patterns depended
on where ratfish were tagged: one tag group remained in one general location with few excursions, whereas a second tag group
moved within a 20-km band with some individuals moving >90 km. These data will help inform food web models’ abilities to quantify
interspecific interactions between ratfish and other components of their community. 相似文献