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31.
32.
András Bardossy Arne Färber Steffen Schönau Bernhard Westrich Thomas Jancke Gerhard Schmid Sven Wurms Karl Stahr Thomas Gaiser Harald Frauenknecht Thilo Streck Joachim Ingwersen Claudia Kreschnak Ulrich Kern Hilke Heppelmann Ekkehard Christoffels Ulrich Förstner Patrick Jacobs 《Environmental Sciences Europe》2006,18(1):67-69
33.
Adrian Vallin Sven Jakobsson Christer Wiklund 《Behavioral ecology and sociobiology》2007,61(9):1419-1424
Large eyespots on the wings of butterflies and moths have been ascribed generally intimidating qualities by creating a frightening
image of a bird or mammal much larger than the insect bearing the eyespots. However, evidence for this anti-predator adaptation
has been largely anecdotal and only recently were peacock butterflies, Inachis io, shown to effectively thwart attacks from blue tits, Parus caeruleus. Here, we test whether large eyespots on lepidopterans are generally effective in preventing attacks from small passerines
and whether the size of insect or bird can influence the outcome of interactions. We staged experiments between the larger
eyed hawkmoths, Smerinthus ocellatus, and the smaller peacock butterflies, I. io, and the larger great tits, Parus major, and the smaller blue tits, P. caeruleus. Survival differed substantially between the insect species with 21 of 24 peacock butterflies, but only 6 of 27 eyed hawkmoths,
surviving attacks from the birds. Thus, surprisingly, the smaller prey survived to a higher extent, suggesting that factors
other than insect size may be important. However, great tits were less easily intimidated by the insects’ eyespots and deimatic
behaviour and consumed 16 of 26, but the blue tits only 8 of 25, of the butterflies and hawkmoths. Our results demonstrate
that eyespots per se do not guarantee survival and that these two insects bearing equally large eyespots are not equally well
protected against predation. 相似文献
34.
A plan to control mercury emissions to the atmosphere and to establish mercury emission limits has recently been elaborated by the European Commission, making it necessary to devise an efficient and cost effective mercury removal technology. Towards this end wet flue gas desulfurization units appear as a promising option for multi-pollutant control. However, more investigation on mercury removal and a greater mercury removal efficiency are required to achieve this objective. In the present work scrubber chemistry and the application of various solid additives to enhance mercury removal in wet scrubbers is evaluated. The results obtained show a significant correlation between mercury removal efficiency and the pH of the scrubber slurry and SO2 concentration. A weaker correlation was observed between oxygen or slurry concentration and removal efficiency. Finally several solid oxides were found to be effective additives for enhancing mercury capture in wet scrubbers. 相似文献
35.
Michela Marchi Sven Erik JørgensenEloy Bécares Ilaria CorsiNadia Marchettini Simone Bastianoni 《Ecological modelling》2011,222(16):2992-3001
Using a dynamic model of Lake Chozas developed by Marchi et al. (2011), we tested three hypotheses about recovery of the indigenous community and water quality after radical changes caused by introduction of an invasive allochthonous crayfish, Procambarus clarkii:
- 1.
- Can the lake resist the pressure of an invasive species, like P. clarkii, by adaptation?
- 2.
- Can the ecosystem recover when all the crayfish are removed and low phosphorus concentrations persist in inflow water?
- 3.
- Does the simulated recovery of submerged vegetation occur at a total phosphorus concentration below 100 mg TP m−3, as estimated by Scheffer et al. (1993), Scheffer (1997), Jeppesen et al. (1998) and Zhang et al. (2003)?
- 1.
- Lake Chozas can at least partly resist by adaptation. A combination of possible parameter changes could lead to a significant increase in eco-exergy.
- 2.
- Removal of the phosphorus represented by crayfish (by harvesting) implies complete recovery of the lake and its eco-exergy, albeit not necessarily with the same organisms having the same properties.
- 3.
- The expected hysteresis created by introduction and harvesting of crayfish is observed under the following conditions: phytoplankton dominance at total phosphorus ≥ about 200-250 mg TP m−3 and submerged vegetation returns at total phosphorus < 100 mg TP m−3.
36.
37.
The neonatal incidence rate of Down syndrome (DS) is well-known to accelerate strongly with maternal age. This non-linearity
renders mere accumulation of defects at recombination during prolonged first meiotic prophase implausible as an explanation
for DS rate increase with maternal age, but might be anticipated from chromosomal drive (CD) for trisomy 21. Alternatively,
as there is selection against genetically disadvantaged embryos, the screening system that eliminates embryos with trisomy
21 might decay with maternal age. In this paper, we provide the first evidence for relaxed filtering stringency (RFS) to represent
an adaptive maternal response that could explain accelerating DS rates with maternal age. Using historical data, we show that
the proportion of aberrant live births decrease with increased family size in older mothers, that inter-birth intervals are
longer before affected neonates than before normal ones, and that primiparae exhibit elevated levels of DS incidence at higher
age. These findings are predicted by adaptive RFS but cannot be explained by the currently available alternative non-adaptive
hypotheses, including CD. The identification of the relaxation control mechanism and therapeutic restoration of a stringent
screen may have considerable medical implications. 相似文献
38.
Christer Wiklund Adrian Vallin Magne Friberg Sven Jakobsson 《Behavioral ecology and sociobiology》2008,62(3):379-389
Insects that hibernate as adults have a life span of almost a whole year. Hence, they must have extraordinary adaptations
for adult survival. In this paper, we study winter survival in two butterflies that hibernate as adults and have multimodal
anti-predator defences—the peacock, Inachis io, which has intimidating eyespots that are effective against bird predation, and the small tortoiseshell, Aglais urticae, which does not have an effective secondary defence against birds. We assessed predation on wild butterflies hibernating
in the attic of an unheated house, as well as survival of individually marked butterflies placed by hand on different sites
in the attic. Our objectives were to assess (1) the number of butterflies that were killed during hibernation, (2) whether
survival differed between butterfly species, and (3) how predation was related to hibernation site and the identity of the
predator. There was a strong pulse of predation during the first 2 weeks of hibernation: 58% of A. urticae and 53% of I. io were killed during this period. Thereafter, predation decreased and butterfly survival equalled 98% during the final 16 weeks
of hibernation. There was no difference in survival between the two butterfly species, but predation was site-specific and
more pronounced under light conditions in locations accessible to a climbing rodent, such as the common yellow-necked mouse,
Apodemus flavicollis. We contend that small rodents are likely important predators on overwintering butterflies, both because rodents are active
throughout winter when butterflies are torpid and because they occur at similar sites. 相似文献
39.
An assertion deeply rooted in the ornithological literature holds that sex-specific mortality causes a sex ratio disparity
(SRD) between complete and incomplete broods. Complete broods are thought to reflect the primary sex ratio before any bias
introduced by developmental mortality. Contrary to this view, however, complete and incomplete broods should exhibit identical
sex ratio distributions even when the sexes experience differential mortality, as shown in the classic paper of Fiala (Am
Nat 115: 442–444, 1980). Therefore, in partially unsexed samples, primary sex ratio biases cannot be distinguished from biases
caused by differential mortality. In addition, complete broods do not represent primary sex ratio more accurately than incomplete
ones and might even be misleading. Despite Fiala’s prediction, SRD does occur in some empirical studies. We show that this
pattern could arise if (1) primary sex ratio affects chick mortality rates independently of sex (direct effect), (2) primary
sex ratio covaries with a variable that also affects mortality rate, or (3) sex differential mortality covaries with overall
mortality rate (indirect effects). Direct effects may cause stronger SRD than indirect ones with a smaller and opposite bias
in the overall sex ratio and could also lead to highly inconsistent covariate effects on brood sex ratios. These features
may help differentiate direct from indirect effects. Most interestingly, differences in covariate effects between complete
and incomplete broods imply that influential variables are missing from the analysis. 相似文献
40.