The Plymouth Student Scientist - Volume 08 - 2015
https://pearl.plymouth.ac.uk/handle/10026.1/12938
2024-03-28T19:23:05ZExposure to predator kairomones influences egg number and size in Littorina littorea
https://pearl.plymouth.ac.uk/handle/10026.1/14106
Exposure to predator kairomones influences egg number and size in Littorina littorea
Raynor, J.; Rundle, S.
Predator kairomones play an important role in intertidal ecosystems, but knowledge on their potential role in influencing maternal effects is lacking. The aim of this study was to test whether egg production by female Littorina littorea was influenced by short-term exposure to predator kairomones before egg laying. Laboratory populations were exposed to predator cues from the intertidal crab Carcinus maenas for nine days, and egg number, egg size, and survivorship of the offspring were measured and compared with those from reference populations. Snails exposed to predator cues produced significantly more eggs, which were also significantly smaller than those produced from mothers in control seawater, suggesting a trade-off between egg size and number. This effect was consistent over time, but egg production decreased in each treatment over the course of the study. Furthermore, eggs from the predator cue treatment had lower survivorship. These results suggest that the presence of predator kairomones in marine environments could significantly alter the reproductive investment strategies in prey species.
STUDENT/STAFF RESEARCH COLLABORATION
2015-01-01T00:00:00ZA palaeoclimatic reconstruction of the Cadair Idris area of Snowdonia, using geomorphological evidence from Younger Dryas cirque glaciers
https://pearl.plymouth.ac.uk/handle/10026.1/14105
A palaeoclimatic reconstruction of the Cadair Idris area of Snowdonia, using geomorphological evidence from Younger Dryas cirque glaciers
Radbourne, B.
The importance of glacier reconstruction lies in the empirical relationship between glacier mass balance and climate. Small glaciers are particularly sensitive to changes in temperature and precipitation, thus the reconstruction of small palaeoglaciers can provide an understanding of past climatic changes in an area. This study conducts glacier and palaeoclimatic reconstructions for four potential palaeoglaciers at Cadair Idris, southern Snowdonia. Three of these are assigned a Younger Dryas age by referring to published literature, and the fourth is assumed to have existed during an earlier glaciation, possibly reflecting deglaciation from the Last Glacial Maximum (LGM). Schmidt Hammer relative age dating is carried out to establish relative ages between landforms within the cirque areas, however the results from this are inconclusive as the process is subject to many errors. The topographically-constrained Younger Dryas cirque glaciers, referred to as Cwm Cau, Cwm Gadair and the small eastern glacier, occupied a total area of 0.963km2. Calculations of Equilibrium Line Altitudes (ELAs) yield an average local ELA of 607m asl. Subsequent palaeoclimatic reconstructions indicate that during the Younger Dryas, annual precipitation levels were similar to, or higher than, present levels, averaging at 2850mm a-1. Consideration is given to the potential for additional mass to be added to the glaciers through snowblow, but it is concluded that the relatively small snowblow factors, ranging from 0.71 to 1.32, would not have contributed much mass to the glaciers. Total avalanche factors range from 0.27 to 0.92 and are suggested to be more likely to contribute mass to the glaciers. Solar radiation maps for the ablation season indicate that the high cirque walls would have provided shading from the most intense incoming solar radiation, thus protecting certain parts of the glaciers and encouraging initial ice accumulation and preservation, possibly explaining the existence of a western lobe of the Cwm Gadair glacier. Finally, calculations of the glaciological dynamics of the glaciers indicate that the small eastern glacier was not, in fact, viable as a glacier under the reconstructed palaeoclimatic conditions.
2015-01-01T00:00:00ZYou can't tickle yourself...or can you? The effect of a hypnotic suggestion on sensory attenuation phenomenon
https://pearl.plymouth.ac.uk/handle/10026.1/14104
You can't tickle yourself...or can you? The effect of a hypnotic suggestion on sensory attenuation phenomenon
Yusuf, S.
The internal motor simulation mechanism is widely believed to generate anticipatory sensory outcomes on the basis of the efferent copy of the motor commands. What is currently unknown is whether the motor prediction mechanism can integrate non-motor inputs such as a hypnotic suggestion in generating sensory predictions. Seventy-two undergraduate students (M=12, F=60) were recruited via Plymouth University participation pool, to undergo a randomised hypnotic suggestion (IV) of either an alien- hand or an alien-foot. The participants were asked to apply tactile stimulation to their left palm (DV) before and after the suggestion and report the tickling sensations. The results revealed an unexpected trend, which just fell short of statistical significance, not only did the control participants get more ticklish over time, but also some participants in the test group felt more in control as a result of alien-hand suggestion. This study found no evidence to support the idea of higher-level functioning forward model. The discussion explores possible explanations for the unexpected findings and highlights a couple of limitations. Finally, implications of the findings are noted with scope of direction for future studies exploring action control theories.
2015-01-01T00:00:00ZThe association of microstructural connectivity in the brain and auditory modulation of representational momentum
https://pearl.plymouth.ac.uk/handle/10026.1/14103
The association of microstructural connectivity in the brain and auditory modulation of representational momentum
Theobald, E.
Perceived displacement from an object’s forward trajectory results in a representational momentum (RM) effect. In a behavioural task, participants watched a video of an actor reaching for/withdrawing from an object after hearing ‘I’ll take it’ or ‘I’ll leave it’, which was either congruent or incongruent with the subsequent action witnessed. The knowledge of other people’s intentions through auditory cues and then the predictions of their actions have been found to create an effect on the strength of RM experienced. The degree to which this auditory information affects the RM effect differs for each individual. This variation could, at least partially, be due to the connectivity between parts of the brain which process auditory information, superior temporal sulcus (STS), and parts processing moving visual stimuli (area MT). Fractional anisotropy (FA) and tract-based spatial statistics (TBSS) analysis of diffusion tensor imaging (DTI) data was used to measure the microstructural connectivity of the areas of interest, which was then correlated with the RM data collected from the behavioural task. Results revealed no significant correlation between auditory modulation of RM effect and brain microstructural connectivity. However results were in line with previous research such as that by Kerzel (2005) and Hudson, Nicholson, Ellis and Bach (2015, submitted) by results being in the anticipated direction and some were approaching significance. Results from this study are integral to our understanding of people’s social perception and can help aid therapies for those with neurological and psychiatric disorders.
2015-01-01T00:00:00Z