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A. Guenther G. Kowalski N. von Engelhardt 《Behavioral ecology and sociobiology》2014,68(10):1661-1667
The prenatal social environment affects offspring development in most studied taxa with potentially lifelong consequences. To understand the adaptive significance of such maternal influences on offspring development, it is important to study their effects on fitness. In guinea pigs, social instability during pregnancy leads to delayed development of male offspring. This has been interpreted as an adaptation to high social densities, where young males need to queue for reproductive opportunities since they cannot out-compete older dominant males. The consequences for male reproductive success are, however, so far unknown. To study the effects of different prenatal social densities on offspring reproductive performance, we housed females individually or in small groups during late pregnancy. Offspring from both treatments were reared together in large groups until independence and thereafter housed in same-sex pairs of the same treatment. We then observed courtship, aggressive behavior, and reproductive success in a low-density context with one male from each treatment competing over access to two females. Sons born to individually housed females initiated more fights, had more social contacts, courted females more, and had a higher reproductive success than sons of group-housed females. Sons born to mothers experiencing low social densities before birth therefore perform better at low social group sizes, suggesting that male development may be adaptively adjusted to anticipated social densities, although performance under high densities still needs to be compared. 相似文献
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Maximilian von Fragstein Gerrit Holighaus Stefan Schütz Teja Tscharntke 《Chemoecology》2013,23(3):181-190
Predatory arthropods are attracted to infochemicals emitted by their herbivore prey or by the prey’s host plants. We studied such a tritrophic system measuring the olfactory responses of three potter wasp species (Symmorphus murarius, Symmorphus gracilis, Discoelius zonalis, Hymenoptera: Eumeninae) to salicylaldehyde, sequestered as a defence compound by Chrysomela leaf beetle larvae when feeding on Salicaceae, and volatile organic compounds (VOCs) emitted by aspen (Populus tremula, Salicaceae). In electroantennographic recordings (EAG), the highly specialized S. murarius that almost exclusively feeds on larvae of Salicaceae-feeding Chrysomela species was more sensitive to salicylaldehyde than the less specialized S. gracilis, feeding on such Chrysomela species but also weevil larvae. In contrast the related D. zonalis, foraging for microlepidoptera caterpillars on various host plants, did not respond at all. Furthermore, the three wasp species responded differently to aspen VOCs in GC–MS/EAD measurements. These results indicate that the sense of smell of predatory potter wasps differs for prey and plant volatiles among related wasp species according to their degree of host specialization. The considerable differences in salicylaldehyde perception suggest that its originally defensive function has backfired as it is used by specialist potter wasps for prey location. This is an important clue on adaptive mechanisms of the highest trophic level of the well-studied evolutionary arms race among Chrysomela leaf beetles, their host plants and their enemies. 相似文献
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Julia Wohlers-Z?llner Antje Biermann Anja Engel Petra D?rge Aleksandra M. Lewandowska Markus von Scheibner Ulf Riebesell 《Marine Biology》2012,159(11):2503-2518
A comparative analysis of data, obtained during four indoor-mesocosm experiments with natural spring plankton communities from the Baltic Sea, was conducted to investigate whether biogeochemical cycling is affected by an increase in water temperature of up to 6?°C above present-day conditions. In all experiments, warming stimulated in particular heterotrophic bacterial processes and had an accelerating effect on the temporal development of phytoplankton blooms. This was also mirrored in the build-up and partitioning of organic matter between particulate and dissolved phases. Thus, warming increased both the magnitude and rate of dissolved organic carbon (DOC) build-up, whereas the accumulation of particulate organic carbon (POC) and phosphorus (POP) decreased with rising temperature. In concert, the observed temperature-mediated changes in biogeochemical components suggest strong shifts in the functioning of marine pelagic food webs and the ocean’s biological carbon pump, hence providing potential feedback mechanisms to Earth’s climate system. 相似文献
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M. Hein S. Rotter M. Schmitt-Jansen P. C. von der Ohe W. Brack E. de Deckere C. Schmitt D. de Zwart L. Posthuma E. M. Foekema I. Muñoz S. Sabater H. Segner E. Semenzin A. Marcomini J. van Gils B. van Hattum L. A. van Vliet 《Environmental Sciences Europe》2010,22(3):217-228
The EU Water Framework Directive (WFD) requires the achievement of good ecological and chemical status in European river basins. However, evidence is increasing that a majority of European water bodies will not achieve this goal. Nutrient emissions and related eutrophication together with hydromorphological alterations have been suggested as the major driving forces of this insufficient ecological status. MODELKEY (511237 GOCE, FP6) provides strong evidence that toxic chemicals also affect the ecological status of European rivers. This was demonstrated in the case study rivers Elbe, Scheldt and Llobregat on different scales. This paper summarises key findings of MODELKEY including recommendations for WFD implementation. We ? provide evidence of toxic stress in aquatic ecosystems, ? provide evidence that impairment of ecological status results from impact of multiple stressors, ? suggest a tiered approach to assess impact of chemicals on ecological status, ? suggest a new approach for deriving candidate compounds for monitoring and prioritisation, ? call for consideration of bioavailability and bioaccumulation in chemical status assessments, ? suggest improvements for WFD water quality monitoring programmes, ? provide new integrated tools for basin-scale risk assessment and decision making, ? developed a Decision Support System to support river basin management. These key results will be presented in a series of ten integrated sections; for the scientific details please refer to publications listed on the MODELKEY website (http://www.modelkey.org/). This article also looks beyond MODELKEY and proposes a combination of MODELKEY diagnostic tools with recent ecological methods to further improve effectiveness of river basin management. 相似文献
608.
P. R. Teske F. R. G. Forget P. D. Cowley S. von der Heyden L. B. Beheregaray 《Marine Biology》2010,157(9):2029-2042
‘No-take’ marine protected areas (MPAs) are successful in protecting populations of many exploited fish species, but it is
often unclear whether networks of MPAs are adequately spaced to ensure connectivity among reserves, and whether there is spillover
into adjacent exploited areas. Such issues are particularly important in species with low dispersal potential, many of which
exist as genetically distinct regional stocks. The roman, Chrysoblephus laticeps, is an overexploited, commercially important sparid endemic to South Africa. Post-recruits display resident behavior and
occupy small home ranges, making C. laticeps a suitable model species to study genetic structure in marine teleosts with potentially low dispersal ability. We used multilocus
data from two types of highly variable genetic markers (mitochondrial DNA control region and seven microsatellite markers)
to clarify patterns of genetic connectivity and population structure in C. laticeps using samples from two MPAs and several moderately or severely exploited regions. Despite using analytical tools that are
sensitive to detect even subtle genetic structure, we found that this species exists as a single, well-mixed stock throughout
its core distribution. The high levels of connectivity identified among sites support the findings of previous studies that
have indicated that inshore MPAs are an adequate tool for managing overexploited temperate reef fishes. Even though dispersal
of adult C. laticeps out of MPAs is limited, the fact that the large adults in these reserves produce exponentially more offspring than their
smaller counterparts in exploited areas makes MPAs a rich source of recruits. We nonetheless caution against concluding that
the lack of structure identified in C. laticeps and several other southern African teleosts can be considered to be representative of marine teleosts in this region in general.
Many such species are represented in more than one marine biogeographic province and may be comprised of regionally adapted
stocks that require individual management. 相似文献
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