Search results for "predation"
showing 10 items of 589 documents
The contribution of insect prey to the total nitrogen content of sundews (Drosera spp.) determined in situ by stable isotope analysis.
2003
Summary • The contribution of insect prey to total N in the carnivorous plants, Drosera rotundifolia and D. intermedia , was quantified in situ and without any experimental manipulation using natural abundance stable isotope analysis. • Samples of D. rotundifolia and D. intermedia , insects and noncarnivorous reference plants were collected from three contrasting locations across Britain. The proportion of Drosera nitrogen obtained from insect prey was calculated by a mixing model using δ 15 N values from the different plant groups. • The mean proportion of Drosera N derived from prey was 50%. There were significant differences in this proportion between sites, and significant differences w…
Socializing makes thick-skinned individuals: on the density of epidermal alarm substance cells in cyprinid fish, the crucian carp (Carassius carassiu…
2010
Published version of an article in the journal: Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology. Also available on SpringerLink: http://dx.doi.org/10.1007/s00359-010-0550-4 In cyprinid fish, density of epidermal club cells (i.e. alarm substance cells) has been found to vary between lakes with different predator fauna. Because predators can be labelled with chemical cues from prey, we questioned if club cell density could be controlled indirectly by predators releasing prey cues. In particular, we suspected a possible feedback mechanism between chemical alarm signals and their cellular source. We raised crucian carp singly and in groups of four.…
Coping with continual danger: assessing alertness to visual disturbances in crucian carp following long-term exposure to chemical alarm signals.
2013
Chemical alarm signals in fish are passively released into the water from ruptured epidermal cells, and induce instant fright responses in conspecifics. Fish also display alarm responses to injured heterospecific skin, as well as to scent of piscivorous predators that have ingested prey. A conspicuous alertness to visual disturbances has also been observed in fish following long-term exposure to extracts of filtered, homogenized skin, but the chemical inducers of such vigilance are actually unknown. We tested if a continual exposure to water-soluble alarm signals, from either conspecifics or heterospecifics, affects alertness of fish. Based on previous experience, it was assumed that alertn…
Trophic ecology of the swimming crab Polybius henslowii Leach, 1820 in Galician and Cantabrian Seas: Influences of natural variability and the Presti…
2008
9 pages, 9 figures, 2 tables.-- Printed version published Nov 15, 2008.
Inferring fish abundance in lakes from subfossil midge (Diptera:Chironomidae) remains
2017
This study assessed the possibility of using subfossil remains of chironomid head capsules to reconstruct past fish abundances in lakes. Using data from 20 Swedish lakes, a weighted average (WA) model was created to predict the abundance of benthivorous fish (cyprinids and perch). Chironomid head capsules, identified to genus, served as the predictors to model already recorded (catch per unit effort) fish data. The relationship of chironomid species composition to lake morphometry, water chemistry and fish abundance were examined using ordination and variation partitioning methods. Moreover, the relationship between fish abundance and two chironomid species traits: body size and activity mo…
Maintenance, feeding and growth of Carybdea marsupialis (Cnidaria: Cubozoa) in the laboratory
2013
9 pages, 5 figures, 1 table
Tracking the evolution of warning signals
1996
EVOLUTIONARYstudies are hampered by a lack of experimental ways in which to test past events such as the origination of aposematism1–7, whereby unpalatable or poisonous prey signal their unprofitability, often by being warningly coloured. Inexperienced predators do learn to avoid unpalatable prey as a result of such signals8–10, but in addition there may be an inherited cautiousness about attacking when common or conspicuous warning signals are evident11–16. As current predators are not naive in the evolutionary sense, it is still not resolved3–7,17,18 whether aposematism originated only in aggregations of prey19,20 or among solitary prey as well21–23. Here we explore this controversy in ev…
Signalling and Reception
2002
Communication, a widespread natural phenomenon, occurs in both animals and plants. Signals are evolved traits that transfer information from one individual (the signaller) to another (the receiver); they can occur in any sensory modality. Keywords: cost and benefits; honesty; mimicry; predation; sexual selection
Postattack deimatic display in the mountain katydid, Acripeza reticulata
2015
Prey use many strategies to avoid being detected by their predators. However, once detected and identified as potentially palatable, prey must employ a second line of defence such as performing a deimatic (startle) display. During the predation sequence, composed of the stages encounter, detection, identification, approach, subjugation and consumption, such defences should be deployed as the predator approaches, but before prey are brought under the predator's control (i.e. before subjugation). We tested this assumption in the mountain katydid (or bush cricket), which is cryptic at rest, but when disturbed flashes spectacular abdominal colours by lifting its wings, and is chemically defende…
Pulsed-Resource Dynamics Constrain the Evolution of Predator-Prey Interactions
2011
Although temporal variability in the physical environment plays a major role in population fluctuations, little is known about how it drives the ecological and evolutionary dynamics of species interactions. We studied experimentally how extrinsic resource pulses affect evolutionary and ecological dynamics between the prey bacterium Serratia marcescens and the predatory protozoan Tetrahymena thermophila. Predation increased the frequency of defensive, nonpigmented prey types, which bore competitive costs in terms of reduced maximum growth rate, most in a constant-resource environment. Furthermore, the predator densities of the pulsed-resource environment regularly fluctuated above and below …