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791.
Frédéric Angelier Henri Weimerskirch Stéphanie Dano Olivier Chastel 《Behavioral ecology and sociobiology》2007,61(4):611-621
The ultimate factors influencing age-specific reproductive performance in birds have been widely discussed, and several hypotheses
have been suggested to explain why young/inexperienced breeders have lower reproductive success than older individuals. In
comparison, proximate factors and, particularly, hormonal mechanisms influencing age-related reproductive performance have
received lesser attention. In this paper, we examined how baseline levels of corticosterone and prolactin, two hormones involved
in reproduction, changed with age and experience in a long-lived bird, the Black-browed albatross (Thallasarche melanophris) during the brooding stage. Corticosterone levels were not linked to age, whereas prolactin levels increased until individuals
reached 15 years of age. First-time breeders had higher corticosterone levels and lower prolactin levels than experienced
ones. Corticosterone levels were not correlated with breeding experience among experienced birds, whereas prolactin levels
slightly increased with advancing experience. Among experienced breeders, there was no effect of individual quality on corticosterone
and prolactin levels. Baseline corticosterone and prolactin levels were respectively, positively and negatively correlated
to time spent fasting/brooding on the nest. Moreover, the probability of successfully fledging a chick was negatively related
to corticosterone levels, but not to prolactin levels. Elevated corticosterone levels in first time breeders may serve as
evidence for depleted body reserves resulting from lower foraging/brooding capabilities and therefore support the constraint
hypothesis. Low prolactin levels in young/inexperienced birds may be interpreted either as evidence for their lower breeding
capacities (constraint hypothesis) or for their limited breeding investment (restraint hypothesis). Finally, we report, for
the first time, the hormonal changes associated with the onset of senescence. The very old and most experienced birds, which
had the lowest probability of successfully fledging a young, displayed elevated corticosterone levels and low prolactin levels,
possibly indicating a degradation of breeding skills and/or a disruption of the endocrine system in senescent birds. 相似文献
792.
Hydrodynamic forces are an important determinant of subtidal community structure, particularly when they limit the distribution
and foraging ability of mobile consumers. We examined the effect of wave action on the rate of movement and destructive grazing
of a kelp bed by the green sea urchin (Strongylocentrotus droebachiensis) under field conditions. We measured density and rate of advance at fixed intervals along ∼100 m of a grazing front over
1 year, and quantified individual movement rates in the barrens 5–10 m behind the urchin front using a time-lapse videography.
Seasonal variation in the mean rate of advance of the front (range: 0–4 m month−1) was explained by changes in urchin density at the front (120–360 individuals m−2), which in turn varied inversely with significant wave height (0.5–2 m). Water temperature (0.8–17.6°C) had no effect on
the rate of advance or on urchin density (aggregation) at the front, except when temperature exceeded 17°C. Movement of individual
urchins also was affected by wave action: we observed a significant decrease in speed and displacement of urchins with increasing
significant wave height. Wave action had no effect on the proportion of urchins moving or the degree of linearity of their
movements. We propose that the decrease in urchin density at the front associated with increased wave action, results from
de-aggregation, which reduces the risk of dislodgement, combined with a reduction in urchin movement in barrens, which supplies
new urchins to the front. 相似文献
793.
Kathryn B. McNamara Therésa M. Jones Mark A. Elgar 《Behavioral ecology and sociobiology》2007,61(8):1177-1184
Male copulation experience may have a profound impact on female reproductive success if male reproductive investment declines
over consecutive copulations and if females are unlikely to re-mate. Male reproductive investment is particularly interesting
in lepidopterans because males produce dimorphic sperm: a fertilizing (eupyrene) and a non-fertilising (apyrene) sperm. In
two experiments, we explored the lifetime reproductive investment of male almond moths, Cadra cautella (also known as Ephestia cautella) and examined its influence on female reproductive success. In the almond moth, females re-mate infrequently and males transfer
sperm in a spermatophore. Attached to the spermatophore is a large chitinous process, the function of which is unknown. One
group of males were permitted consecutive copulations with virgin females and the amount of sperm and size of the spermatophore
transferred were compared for all females. We found that the number of both eupyrene and apyrene sperm per ejaculate decreased
with his increased mating frequency, while the size of the spermatophore process decreased dramatically after the male’s first
copulation. In a second experiment, we allowed males to mate with females throughout their lives and then compared female
fecundity and fertilisation success. We found no obvious decrease in female fecundity and fertilisation success with increased
male copulation experience, despite the likely reduction in male gametic investment. We discuss potential explanations for
the development of this enlarged and elaborate first spermatophore of male almond moths given that it confers no clear fitness
advantage to females. 相似文献
794.
Véronique Thériault Louis Bernatchez Julian J. Dodson 《Behavioral ecology and sociobiology》2007,62(1):51-65
Salmonids are known for the occurrence in sympatry of two life-history forms, one that undergoes migration to sea before returning
to freshwater to reproduce (anadromous) and one that inhabits freshwater without a migration phase (resident). Whereas one
breeding population is often suggested by population genetic studies, mating patterns have rarely been directly assessed,
especially when both sexes are found within each life-history form. By using highly polymorphic microsatellite loci and parentage
analysis in a natural population of sympatric anadromous and resident brook charr (Salvelinus fontinalis), we found that gene flow occurred between the two forms and was mediated by resident males mating with both resident and
anadromous females. Determinants of reproductive success, estimated by the number of surviving juveniles (ages 1 and 2 years),
differed between the sexes. No strong evidence of the influence of size on individual reproductive success was found for males,
whereas larger females (and hence most likely to be anadromous) were more successful. The higher individual reproductive success
of anadromous fish compared to residents was mainly explained by this higher reproductive success of anadromous females. We
suggest that resident males adopt a “sneaking” reproductive tactic as a way of increasing their reproductive success by mating
with females of all sizes in all habitats. The persistence of the resident tactic among females may be linked to their advantage
in accessing spatially constrained spawning areas in small tributary streams unavailable to larger females. 相似文献
795.
André Chiaradia Yan Ropert-Coudert Akiko Kato Thomas Mattern Julija Yorke 《Marine Biology》2007,151(4):1535-1542
Little Penguins, Eudyptula minor, breed in several small colonies in New Zealand and Australia. In this study, we compare the birds’ diving performances at
different sites situated throughout their breeding range. Environmental conditions and breeding success vary drastically amongst
colonies, but all birds feed on similar types of prey and face similar limitations on their foraging range. We examined several
diving parameters and calculated the proportion of foraging zone available during breeding to examine whether oceanographic
and geographic factors in the foraging zone can explain variations in diving behaviour and fledging success among the different
colonies. In colonies with high fledging success, Penguin Island and Oamaru, penguins made shallow dives <50 m depth and had
lower diving effort. More than 90% of the foraging zone was in waters <50 m depth in these colonies. Motuara Island also has
shallow waters with 95% <50 m depth, but the fledging success was low. Phillip Island has only 42% of waters <50 m and comparatively
low fledging success. Thus, penguins dived deeper and showed a higher diving effort in colonies with lower fledging success
(Motuara Island and Phillip Island), indicating that they were disadvantaged compared to conspecifics from other colonies
that dived shallower and with a lesser diving effort. We concluded that bathymetry is an important factor, but not the only
one, which influences fledging success. 相似文献
796.
F. Mougeot J. Martínez-Padilla L. Pérez-Rodríguez G. R. Bortolotti 《Behavioral ecology and sociobiology》2007,61(5):741-751
Among the most familiar sexual signals are red, yellow, and orange sexual traits pigmented by carotenoids. Many birds can
detect near-ultraviolet (UV) light, and UV signals can play key roles in mate choice. Grouse (Tetraonidae) exhibit bright
carotenoid-dependent sexual ornaments, their supra-orbital combs, which to humans appear orange-red. Combs also reflect in
the UV, which is not visible to humans but is likely to be visible to grouse. In male red grouse Lagopus lagopus scoticus, we show that comb UV reflectance decreases with increasing comb size and redness. By removing the epidermis of combs, where
carotenoid pigments are, we show that the UV reflectance is a property of the dermis, underneath the red pigmented epidermis.
Carotenoid pigmentation of combs acted as a mask to reduce reflectance by the dermis in the range 400–550 nm and in the UV,
300–400 nm. Patagium skin (non-ornamental skin under the wing) also reflects in the UV, but epidermis removal on this bare
part tended to reduce UV reflectance, whereas removal of the red epidermis of combs increased UV reflectance. Males in better
condition (greater body mass relative to size) had bigger and redder combs, but with less UV. Thus, carotenoid pigments of
grouse combs are deposited on a white background with significant UV reflectance, which can influence how the signal is perceived
by conspecifics. Carotenoid-based traits exhibit UV reflectance in a number of species, but how UV reflectance and carotenoid
pigmentation influence colour remains little known for integumentary ornaments compared to plumage traits. UV vision is not
uncommon in birds and other animals, so future studies should investigate how UV reflectance influences the perception of
carotenoid-based signals of quality. 相似文献
797.
Frédéric Mineur Mark P. Johnson Christine A. Maggs Herre Stegenga 《Marine Biology》2007,151(4):1299-1307
Hull fouling is thought to have been the vector of introduction for many algal species. We studied ships arriving at a Mediterranean
harbour to clarify the present role of commercial cargo shipping in algal introductions. A total of 31 macroalgal taxa were
identified from 22 sampled hulls. The majority of records (58%) were of species with a known cosmopolitan geographical distribution.
Due to a prevalence of cosmopolitan species and a high turnover of fouling communities, species composition of assemblages
did not appear to be influenced by the area of origin, length of ship or age of coating. In the light of the present results,
hull fouling on standard trading commercial vessels does not seem to pose a significant risk for new macroalgal species introductions.
However, a high proportion of non-cosmopolitan species found on a ship with non-toxic coating may modify this assessment,
especially in the light of the increasing use of such coatings and the potential future changes in shipping routes. 相似文献
798.
Jelena Cvejic Sylvie Tambutté Severine Lotto Momir Mikov Ivan Slacanin Denis Allemand 《Marine Biology》2007,152(4):855-862
Corallium rubrum is the most famous and precious coral due to the intense characteristic red colour of its skeleton. We have determined the
presence of carotenoids in natural samples of C. rubrum from Marseille, Riou, and investigated their chemical composition. Analysis was performed both on soft tissues and hard tissues
including spicules and skeleton. Since hard tissues are made of a mineral fraction and an organic fraction obtained after
demineralization, extraction was performed both with and without demineralization by EDTA. The extracts were analyzed by complementary
methods of TLC, HPLC/DAD and HPLC/MS. The components were separated by RP-18 chromatography column using acetonitrile/methanol
for HPLC/DAD and acetonitrile/water gradient for HPLC/MS analysis. Our results give the first evidence of the presence of
canthaxanthin, 4,4′-diketo-β-carotene, as the major carotenoid in all samples. Spicules exhibited higher content in carotenoids
than skeleton. Demineralization treatment improved the efficiency of carotenoid extraction by an average factor of 5 and showed
that organic matrix contains canthaxanthin. 相似文献
799.
Jesús M. Avilés Bård G. Stokke Arne Moksnes Eivin Røskaft Anders P. Møller 《Behavioral ecology and sociobiology》2007,61(3):475-485
The outer layer of the eggshell in birds is in many cases covered by pigments that are assumed to be genetically determined traits with a negligible environmental component. To test the hypothesis that spring environmental conditions (i.e., temperature and rainfall) may affect bird egg pigmentation, we measured by spectrophotometry and photography egg coloration and spottiness on reed warbler (Acrocephalus scirpaceus L.) clutches parasitized by the common cuckoo (Cuculus canorus L.) collected over a period of 24 years and preserved in the Zoological Museum, Copenhagen, Denmark. In addition, we investigated whether spring environmental conditions may influence the coevolutionary relationship between the cuckoo and its host via changes in cuckoo–host egg matching. Generalized mixed models revealed that reed warbler eggs were more brilliant in those springs with a higher rainfall and tended to be bluer and greener in springs with a lower relative temperature. On the other hand, cuckoo eggs were bluer and greener in springs with a higher rainfall. Cuckoo–host egg matching in blue-greenness and spottiness was better in springs with a higher rainfall. These results provide support for the existence of an environmental component on bird egg coloration and suggest that environmental factors may potentially affect the outcome of important features of the arms race between cuckoos and reed warblers. 相似文献
800.
Qijie Zhang Benoit Laurent Fanny Velay-Lasry Richard Ngo Claude Derognat Béatrice Marticoren Armand Albergel 《环境科学学报(英文版)》2012,24(1):102-111
An air pollution forecast system, ARIA Regional, was implemented in 2007-2008 at the Beijing Municipality Environmental Monitoring Center, providing daily forecast of main pollutant concentrations. The chemistry-transport model CHIMERE was coupled with the dust emission model MB95 for restituting dust storm events in springtime so as to improve forecast results. Dust storm events were sporadic but could be extremely intense and then control air quality indexes close to the source areas but also far in the Beijing area. A dust episode having occurred at the end of May 2008 was analyzed in this article, and its impact of particulate matter on the Chinese air pollution index (API) was evaluated. Following our estimation, about 23 Tg of dust were emitted from source areas in Mongolia and in the Inner Mongolia of China, transporting towards southeast. This episode of dust storm influenced a large part of North China and East China, and also South Korea. The model result was then evaluated using satellite observations and in situ data. The simulated daily concentrations of total suspended particulate at 6:00 UTC had a similar spatial pattern with respect to OMI satellite aerosol index. Temporal evolution of dust plume was evaluated by comparing dust aerosol optical depth (AOD) calculated from the simulations with AOD derived from MODIS satellite products. Finally, the comparison of reported Chinese API in Beijing with API calculated from the simulation including dust emissions had showed the significant improvement of the model results taking into account mineral dust correctly. 相似文献