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701.
702.
Arsenic bioaccessibility in a gold mining area: a health risk assessment for children 总被引:1,自引:0,他引:1
Ono FB Guilherme LR Penido ES Carvalho GS Hale B Toujaguez R Bundschuh J 《Environmental geochemistry and health》2012,34(4):457-465
High concentrations of total arsenic (As) have been measured in soils of gold mining areas of Brazil. However, bioaccessibility tests have not yet been conducted on those materials, which is essential for better health risk estimates. This study aimed at?evaluating As bioaccessibility in samples from a gold mining area located in Brazil and assessing children's exposure to As-contaminated materials. Samples were collected from different materials (a control and four As-contaminated soils/sediments) found in a gold mine area located in Paracatu (MG), Brazil. Total and bioaccessible As concentrations were determined for all samples. The control soil presented the lowest As concentrations, while all other materials contained high total As concentrations (up to 2,666?mg?kg(-1)) and low bioaccessible As percentage (<4.2%), indicating a low risk from exposure of resident children next to this area. The calculated dose of exposure indicated that, except for the pond tailings, in all other areas, the exposure route considering soil ingestion contributed at most to 9.7% of the maximum As allowed ingestion per day (0.3?μg?kg(-1) BW day(-1)). 相似文献
703.
Hea-Youn?Lee Hyo-Taek?ChonEmail author Manfred?Sager Laszlo?Marton 《Environmental geochemistry and health》2012,34(1):5-12
This study presents the level of platinum in urban environment in and around Seoul, the capital city of Korea. Road dust, roadside soil, and tree bark samples were collected from the sites of various traffic volumes and from control sites in the suburbs. The above samples were analyzed for Pt by ICP-MS and other heavy metals by ICP-OES. Platinum levels in road dusts and roadside soils from Seoul were in the range of 3.8–444 ng/g (av. 115.0 ng/g) and 0.7–221 ng/g (av. 49.7 ng/g), respectively, whereas those in the suburbs were in the range of 2.3–5.2 ng/g (av. 3.9 ng/g) in road dusts and 0.4–5.1 ng/g (av. 2.4 ng/g) in roadside soils. The highest Pt levels in road dusts were found from major roads with high traffic volume. The remarkable difference in average Pt level between heavy traffic roads (av. 132.2 ng/g) and light traffic roads (av. 22.8 ng/g) reflects that an important source of Pt in roadside environment is automobile catalytic converter. High Pt level in road dust was found from the site of erratic stop–start driving condition, for example, 178 ng/g Pt in road dust around a vehicle crossing gate. Platinum level in tree barks ranged from 0.9 to 4.5 ng/g, which indicates the existence of Pt-containing particulate matter in the atmosphere. Road dusts with high Pt level were enriched in traffic-related heavy metals. 相似文献
704.
Time of departure and landing of nocturnal migrants are of great importance for understanding migratory strategy used by birds.
It allows us to estimate flying time and hence the distance that migrants cover during a single night. In this paper, I studied
the temporal schedule of nocturnal departures of European robins during spring migration. The study was done on the Courish
Spit on the Baltic Sea in 1998–2003 by retrapping 51 ringed birds in high mist nets during nocturnal migratory departure.
Take-offs of individual birds occurred between the first and tenth hour after sunset (median 176 min after sunset). Departure
time was not related to fuel stores at arrival and departure, stopover duration and progress of the season. The results suggest
that one reason for temporal variation in take-off time was differential response of European robins with high and low motivation
to depart to such triggers as air pressure and its trend. If these parameters reach a certain minimum threshold shortly before
sunset, robins with a high migratory motivation take off in the beginning of the night. When air pressure or its trend reaches
a maximum, it may trigger to take off later during the night birds with lower initial motivation for departure, including
those that have low refuelling efficiency. In regulation of timing of take-offs of robins, an important role is also played
by their individual endogenous circadian rhythm of activity which is related to the environment in a complex way. 相似文献
705.
Judith?MoralesEmail author Roxana?Torres Alberto?Velando 《Behavioral ecology and sociobiology》2012,66(1):135-143
In evolutionary biology, whether parents should enhance or reduce parental care according to mate ornamentation is a subject
of great debate. However, the evolution of female ornaments can shed light on this question. In theory, female ornamentation
should be traded off against fecundity and thus cannot be wholly informative to males without a direct indication of fecundity.
Hence, direct cues of offspring quality should affect the relationship between male investment and female ornamentation. Under
this hypothesis, we manipulated two direct cues of offspring quality (egg size and color) after first egg laying in the blue-footed
booby and registered male incubation patterns. In this species, foot color is a dynamic signal of current condition and in
females is traded off with egg size. We found that males spent more time incubating when paired with dull females but only
in nests with large eggs. Males also spent less time incubating small dull eggs. Results indicate that egg size, a direct
cue of reproductive value, affected the relationship between male effort and female ornamentation. Males may be willing to
help females that have invested in offspring at the expense of ornamentation, which suggests compensation when females are
in low condition. Another possibility is that males relax their effort when paired with highly ornamented and fecund females
because they have high parenting abilities. Our findings suggest that the information conveyed by female ornaments may depend
on direct cues of fecundity. Results also highlight that parental decisions are complex, modulated by a combination of information
sources. 相似文献
706.
Pawe? R?k 《Behavioral ecology and sociobiology》2012,66(12):1629-1637
Male mating experience was shown to play an important role in settling conflicts between males; however, little is known about whether and how prior access to females influences male behavior during intersexual interactions and female choice itself. Here, I experimentally test this relationship in the house cricket (Acheta domesticus) by combining one-on-one interaction between the male and female with direct comparison of males by the female, but precluding aggression between males. I found that solitary males were more active during subsequent courtship displays than paired males, suggesting the detrimental effect of mating on courtship performance. At the same time, females spent significantly more time close to solitary males or playbacks of male's natural courtship songs, and responded positively to the condition of males, ignoring body size of males. In contrast, females responded similarly to computer-modified playbacks of courtship songs of solitary and paired males with standardized rate of phrases and amplitudes; however, when females were additionally allowed to contact with anesthetized males they spent more time close to bigger males, irrespective of the acoustic parameters of courtship songs. These results show that although females were able to differentiate between many behavioral and morphological characteristics of males, including voluntary and intrinsic ones, they preferred traits conditional upon the costliness of male's displays. In addition, mating experience appeared to be a crucial factor in the choice of a particular costly mating strategy by males. 相似文献
707.
Julie Marmet Beno?t Pisanu Jean-Louis Chapuis Gwena?l Jacob Emmanuelle Baudry 《Behavioral ecology and sociobiology》2012,66(11):1449-1457
While sexual selection in mammals with female defense systems has historically received considerable attention, much less is known about the factors affecting reproductive success in mammalian species with scramble competition mating systems. Using mark–recapture techniques and DNA microsatellite loci to assign parentage, we examined the mating system and factors affecting the variation of the annual reproductive success in an introduced population of the Siberian chipmunk, Tamias sibiricus, a small, monomorphic, solitary squirrel. Our analyses showed that breeding females were spatially dispersed, setting the stage for a scramble competition mating system. Male reproductive success was positively associated with the size of the home range. The strength of sexual selection on this behavioral trait was very strong, equaling previous estimates for morphological traits in female defense mating systems. These findings suggest that a behavioral trait, space use, strongly influences the annual reproductive success in males, which is consistent with expectations in a scramble competition mating system. In both sexes, reproductive success was influenced by habitat, with twice as many juveniles produced in semi-open than in closed habitat, possibly due to differences in food availability between the two habitats. 相似文献
708.
Christopher N. Templeton ?a?lar Ak?ay S. Elizabeth Campbell Michael D. Beecher 《Behavioral ecology and sociobiology》2012,66(11):1503-1509
Animals frequently use signals to modulate aggressive interactions. Establishing that a signal is aggressive or threatening requires demonstrating that it is more commonly used in agonistic contexts, that it predicts subsequent aggressive behaviors by the sender, and that receivers respond differently to this signal. Like many birds, song sparrows (Melospiza melodia) produce a low-amplitude “soft song” vocalization that has been hypothesized to be an aggressive signal. Soft song meets the first two criteria, but previous research has failed to demonstrate that soft song provokes aggression or that receivers even perceive soft song differently from normal loud song. We used a playback experiment with taxidermic mount presentation to test whether territorial male song sparrows respond differently to loud and soft song playbacks. Subjects reacted more strongly to the soft song playback by approaching the mount more closely, increasing wing wave displays, and increasing the proportion of their own songs that were soft songs, with further trends toward increasing the number of flights and attacks. These results confirm that soft song is a conventional signal of aggression in song sparrows and that increased receiver retaliation maintains its reliability. 相似文献
709.
Jes Johannesen J?rg Thomas Wennmann Yael Lubin 《Behavioral ecology and sociobiology》2012,66(10):1387-1398
Group living in spiders is characterised by two principle modes, the cooperative social mode and the colonial non-cooperative mode. Kin-relationships due to reduced dispersal determine population genetic structure in social spiders, but the dispersal mechanisms underlying group structure remain poorly understood in colonial spiders. Assuming similar ecological benefits of group living, we address the question whether reduced dispersal shapes population structure in a colonial spider, Cyrtophora citricola (Araneidae). We analysed dispersal by studying settling decisions under semi-natural conditions in experimental trees with and without colonies, and in natural populations, we estimated dispersal and colony structure using population genetic analyses. The propensity to disperse decreased with increasing age in experimental colonies. Adult females did not disperse in the experiment. Sub-adult female spiders preferred trees with a colony to trees without a colony. Dispersal in third instar juveniles was influenced significantly by wind but not by the presence of a colony. Thus, we showed that being in a colony did not inhibit juvenile dispersal, but pre-mating females were philopatric. Genetic differentiation among colonies in natural populations was heterogeneous, colonies being either little or highly differentiated. The heterogeneous structure is likely caused by colony founding by one or a few females followed by dispersal among perennial colonies. Gene flow, however, was slightly male-biased. The experimental and indirect, genetic approaches combined showed that dispersal and the breeding system of C. citricola resemble that of solitary spiders, with juvenile dispersal occurring in both sexes, while the colonial distribution is maintained by female philopatry. 相似文献
710.
Vicki?L.?StokesEmail author Peter?B.?Banks Roger?P.?Pech 《Behavioral ecology and sociobiology》2012,66(2):329-338
Residency status of individuals in populations may be an important determinant of the outcomes of interspecific competition
between native and introduced species. We examined direct behavioral interactions between two similarly sized rodents, the
alien Rattus rattus and native Rattus fuscipes when they were respective residents and intruders in a small enclosure. Resident individuals were dominant in their behaviors
toward intruders irrespective of the species that was resident. In contrast, interactive behaviors between conspecifics were
often neutral or amicable, supporting suggestions that R. rattus and R. fuscipes are social animals. We then tested whether rodent species use heterospecific odors to avoid aggressive competitive interactions
and partition space in the field. Neither R. fuscipes nor R. rattus responded to traps scented with the odors of male or female heterospecifics. If R. fuscipes does not recognize the odor of introduced R. rattus, then odors will not be cues to the presence or territorial space of competing heterospecifics. Rather, findings from both
enclosure and field trials suggest that direct aggressive interactions between individual R. rattus and R. fuscipes probably facilitate segregation of space between these two species in wild populations, where resident animals may typically
be the winners and exclude heterospecific intruders. These findings have implications for the invasion success of introduced
rodents such as R. rattus into intact forests, where native populations may have competitive advantage because of their residency status. 相似文献