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21.
Petri T. Niemel? Anssi Vainikka Sonja Lahdenper? Raine Kortet 《Behavioral ecology and sociobiology》2012,66(5):645-652
Population density regulates the strength of intraspecific competition and may thereby be reflected in life-history variables,
such as development time, growth rate, or investment in immune defense. However, population density may also affect the fitness
payoffs of different behaviors and consequently shape the development of personality. Here we studied if population density
during nymphal development (one, four, or ten individuals raised together) affects the level of boldness, measured as the
latency time to recover from freezing and emerge from a shelter, aggressiveness towards conspecifics or their correlation
at the adult stage in the field crickets, Gryllus integer. In addition, we tested if individuals invest more resources in immune function or speed up their development in response
to a high conspecifics density during ontogeny. Nymphal density did not affect adult boldness or aggressiveness towards conspecific
males per se, but these variables showed a negative association, i.e., indicated an unconventional behavioral syndrome in
the highest density treatment. Supporting the effectiveness of density treatments in inducing plastic responses, individuals
reached maturity sooner and invested more resources in immune function in the highest nymphal density group compared to groups
consisting of one or four individuals. Our results suggest that population density may play an important role in shaping both
the realized life history and development of behavioral syndromes. 相似文献
22.
Consistent individual differences in boldness have been identified in many species and can have important effects on fitness.
In most animals, juveniles face different costs and benefits of risk-taking behavior than do adults. Furthermore, profound
changes in hormones, morphology and environment often occur when juveniles become adults. Therefore, the boldness of individuals
might change with ontogeny. In field crickets, adult males call to attract sexually receptive females, and male calling increases
predation risk. We measured the repeatability of boldness (latency to emerge from a safe refuge) in both male and female crickets.
Each cricket was tested once as a small nymph and once as an adult. We found that boldness was repeatable across metamorphosis
in females, but not in males. Males became less bold with maturation, a result that we predicted because of the risk associated
with calling for mates. We also found that in general, nymphs were bolder than adults and that individuals spent more time
immobile in response to a predator cue when they were nymphs, versus when they were adults. 相似文献
23.
Geographic information system based manure application plan 总被引:3,自引:0,他引:3
A geographic information system (GIS) based manure application plan has been developed for the site-specific application of animal waste to agricultural fields in the Westbrook sub-catchment of the Murray-Darling Basin, south-east Queensland, Australia. Sites suitable for animal waste application were identified using a GIS based weighted linear combination (WLC) model. The degree of land suitability for animal waste application was determined using a range of social, economic, environmental, and agricultural factors. As eutrophication and toxic blue-green algae blooms are a known problem in the catchment, the manure application rates were limited to the rate of crop phosphorus removal. Maximum manure application rate was calculated spatially by taking the crop nutrient (P2O5) requirement and the manure nutrient (P2O5) content into account. The environmental suitability of the fields receiving animal waste was considered in prescribing the final application rate of solid and liquid manures generated by local animal production facilities. The degree of site suitability of the agricultural fields was also used to suggest manure management practices to minimise the socio-environmental risks and increase the nutrient use efficiency of the applied manure. The amount of ammonium nitrogen (NH4-N) that would be added to the soil by satisfying the P2O5 requirement using manure sources was also calculated and an applied NH4-N map was created. This map could be used to assist farmers identify additional nitrogen requirements after manure application. 相似文献
24.
Recruitment in social insects often involves not only inducing nestmates to leave the nest, but also communicating crucial
information about finding profitable food sources. Although bumblebees transmit chemosensory information (floral scent), the
transmission mechanism is unknown as mouth-to-mouth fluid transfer (as in honeybees) does not occur. Because recruiting bumblebees
release a pheromone in the nest that triggers foraging in previously inactive workers, we tested whether this pheromone helps
workers learn currently rewarding floral odours, as found in food social learning in rats. We exposed colonies to artificial
recruitment pheromone, paired with anise scent. The pheromone did not facilitate learning of floral scent. However, we found
that releasing floral scent in the air of the colony was sufficient to trigger learning and that learning performance was
improved when the chemosensory cue was provided in the nectar in honeypots; probably because it guarantees a tighter link
between scent and reward, and possibly because gustatory cues are involved in addition to olfaction. Scent learning was maximal
when anise-scented nectar was brought into the nest by demonstrator foragers, suggesting that previously unidentified cues
provided by successful foragers play an important role in nestmates learning new floral odours. 相似文献
25.
An evaluation of the applicability of microarrays for monitoring toxic algae in Irish coastal waters
Gary R McCoy Nicolas Touzet Gerard TA Fleming Robin Raine 《Environmental science and pollution research international》2013,20(10):6751-6764
The applicability of microarrays to monitor harmful algae across a broad range of ecological niches and toxic species responsible for harmful algal events has been one of the key tasks in the EU Seventh Framework Programme (FP7)-funded Microarrays for the Detection of Toxic Algae project. The technique has a strong potential for improving speed and accuracy of the identification of harmful algae and their toxins to assist monitoring programmes. Water samples were collected from a number of coastal sites around Ireland, including several that are used in the Irish National Phytoplankton and Biotoxin Monitoring Programme. Ribosomal RNA was extracted from filtered field samples, labelled with a fluorescent dye, and hybridised to probes spotted in a microarray format on a glass slide. The fluorescent signal intensity of the hybridisation to >120 probes on the chip was analysed and compared with actual field counts. There was a general agreement between cell counts and microarray signal. Results are presented for field samples taken from a range of stations along the Irish coastline known for harmful algal events during the first field trial (July 2009–April 2010). 相似文献