PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “predator-prey interactions”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

12 recordsLinked to original sources
PubMed1975

A multigroup model for predator-prey interactions.

The predator-prey interactions between the protozoan Tetrahymena pyriformis and the bacterium Aerobacter aerogenes have been studied experimentally and mathematically. A mathematical model for the ciliates defines the mass distribution of cells within the population. The resulting model equations are solved by the use of multigroup theory. Experimental data from batch and continuous flow rectors are compared with the results of the numerical integration.

Carbon↗
PubMed1978

A semi-Markovian model for predator-prey interactions.

In the study of population dynamics, the predator-prey system is recognized as a vitally important aspect in natural population control. On aspect of predator-prey interactions is studied in this paper. The attack cycle of a predator is assumed to consist of four different activities, namely, search, pursuit, handle and eat, and digestion. A semi-Markovian model is proposed to obtain the number of prey devoured by a predator during the activity of a day. The advantages of a new semi-Markovian model to the queueing model developed by Curry and DeMichele (1977) is demonstrated, as the results from the semi-Markovian model are closer to Holling's (1966) experimental data than their results, which were based entirely on Poisson assumptions.

Animals↗
PubMed1976

The effect of size on the fast-start performance of rainbow trout Salmo cairdneri, and a consideration of piscivorous predator-prey interactions.

The fast-start (acceleration) performance of seven groups of rainbow trout from 9-6 to 38-7 cm total length was measured in response to d.c. electric shock stimuli. Two fast-start kinematic patterns, L- and S-start were observed. In L-starts the body was bent into an L or U shape and a recoil turn normally accompanied acceleration. Free manoeuvre was not possible in L-starts without loss of speed. In S-starts the body was bent into an S-shape and fish accelerated without a recoil turn. The frequency of S-starts increased with size from 0 for the smallest fish to 60-65% for the largest fish. Acceleration turns were common. The radius of smallest turn for both fast-start patterns was proportional to length (L) with an overall radius of 0-17 L. The duration of the primary acceleration stages increased with size from 0-07 s for the group of smallest fish to 0-10 s for the group of largest fish. Acceleration rates were independent of size. The overall mean maximum rate was 3438 cm/s2 and the average value to the end of the primary acceleration movements was 1562 cm/s2. The distance covered and velocity attained after a given time for fish accelerating from rest were independent of size. The results are discussed in the context of interactions between a predator and prey fish following initial approach by the predator. It is concluded that the outcome of an interaction is likely to depend on reaction times of interacting fish responding to manoeuvres initiated by the predator or prey. The prey reaction time results in the performance of the predator exceeding that of the prey at any instant. The predator reaction time and predator error in responses to unpredictable prey manoeuvre are required for prey escape. It is predicted that a predator should strike the prey within 0-1 s if the fish are initially 5-15 cm apart as reported in the literature for predator-prey interactions. These distances would be increased for non-optimal prey escape behaviour and when the prey body was more compressed or depressed than the predator.

Animals↗
PubMed1976

Selective cannibalism in the rotifer asplanchna sieboldi: contact recognition of morphotype and clone.

Populations of A. sieboldi reproduce primarily by diploid femal parthenogenesis. Females may exhibit a pronounced, nongenetic polymorphism which is controlled by the diet. The cruciform and especially the campanulate morphotypes are larger than the saccate morphotype and are cannibalistic. Direct observations of various predator-prey interactions between the different morphotypes of two taxonomically distinct clones show that the feeding responses of cannibals after actual prey contact are predictable and extremely selective. Companulates from clone B respond regularly to saccate but only rarely to cruciform or campanulate clonemates; the same predators typically respond to cruciforms and campanulates from clone C. Cruciforms from clone C rarely respond to saccate and cruciform clonemates but readily attack all morphotypes from clone B. In contrast, campanulates from clone C show no selectivity. Morphotype- and clone-specific recognition responses, which are mediated by coronal contact chemoreceptors, permit efficient prey discrimination and protection withotu involving prey handling or development of energy-demanding, defensive structures, such as the body-wall outgrowths of the cruciform morphotype. Selective feeding of cannibals may increase the fitness of a clone, both by effecting a more adaptive distribution of its morphotypes and by enhancing its ability to compete directly and indirectly with cooccurring clones. The magnitude of cannibalism in this rotifer may be dependent upon a complex suite of heterogeneous predator-prey interactions and greatly affected by shifting densities and distributions of different clones and female morphotypes.

Age Factors↗
PubMed1976

Predator prey interactions with time delays.

A general (Volterra-Lotka type) integrodifferential system which describes a predator-prey interaction subject to delay effects is considered. A rather complete picture is drawn of certain qualitative aspects of the solutions as they are functions of the parameters in the system. Namely, it is argued that such systems have, roughly speaking, the following features. If the carrying capacity of the prey is smaller than a critical value then the predator goes extinct while the prey tends to this carrying capacity; and if the carrying capacity is greater than, but close to this critical value then there is a (globally) asymptotically stable positive equilibrium. However, unlike the classical, non-delay Volterra-Lotka model, if the carrying capacity of the prey is too large then this equilibrium becomes unstable. In this event there are critical values of the birth and death rates of the prey and predator respectively (which hitherto have been fixed) at which "stable" periodic solutions bifurcate from the equilibrium and hence at which the system is stabilized. These features are illustrated by means of a numerically solved example.

Animals↗
PubMed1977

Components of predation defense behavior in chickens: evidence for endogenous rhythmicity.

The manifestation of diurnal periodicity and the extent of its control by the photoperiod was assessed in three predation defense reactions which constitute either components or outcomes of a predator-prey interaction sequence. Two-hundred White Leghorn chicks were reared from hatching for one week in either 24L or 12L and then tested at one of two clock hours previously demonstrated to define peak and trough response for one of the components. Putative evidence was found for an endogenous source of the periodicity manifested in all reactions. Maintenance schedule did not entrain the periodicity, but simple room entry and handling elicited anti-predator reactions, the extent of which varied as a function of clock hour. A general model of predation defense behavior was proposed.

Animals↗
PubMed1979

The dynamics of infection of Tribolium confusum by Hymenolepis diminuta: the influence of infective-stage density and spatial distribution.

The mean parasite burden of a population of Tribolium confusum is shown to rise to a plateau as the exposure density of infective eggs of Hymenolepis diminuta increases. The level of this plateau is shown to be dependent on the nutritional status of the host population, being depressed from approximately 18 cysticeroids/beetle in hosts which have been starved prior to experimentation, to approximately 2 cysticercoids/beetle in satiated hosts. A simple model is used to describe the shape of this infection functional response in terms of the predator-prey interaction between hosts (T. confusum) and parasite infective stages (H. diminuta eggs). The distribution of successful infections/host is shown to be over-dispersed, even when hosts are exposed to infective stages arranged in a uniform spatial pattern. The over-dispersion of parasite numbers/host is shown to become more severe as the spatial pattern of infective stages changes from under-dispersed, through random, to over-dispersed. Experimental results are discussed in relation to the dynamics of parasite-host interactions, in which infection takes place by host ingestion of a free-living infective stage.

Feeding Behavior↗
PubMed2026

Biocontrol potential and molecular basis of predation in a marine raptorial ciliate.

Predator-prey interactions are widespread across organisms and are key drivers of morphological and behavioral evolution. Despite this, predation remains poorly understood among microbial eukaryotes, mostly due to the absence of a tractable experimental system that allows quantitative, reproducible investigation. This study establishes the marine raptorial ciliate Chaenea vorax as a highly efficient predator, with Rosenzweig-MacArthur model simulations based on predation data showing that only a few dozen individuals can eliminate the vast majority of the facultatively pathogenic ciliate Uronema marinum within 1-2 days, providing a quantitative basis for developing predator-based biocontrol strategies in aquaculture. Genomic analysis shows that C. vorax possesses a highly fragmented macronuclear genome enriched with predation-related pathways, including calcium-mediated contractility, cellular proteolysis, toxin expulsion systems, among others. Transcriptomic profiling during predation events further demonstrates significant upregulation of genes involved in cytoskeletal remodeling, proteolytic activity, and cellular detoxification. Evolutionary analyses suggest that C. vorax has an extremely long evolutionary history, exceptionally high nucleotide diversity even among ciliates, and gene family expansions linked to predatory adaptation. Although the prey possesses certain defensive mechanisms (e.g. trichocysts), these are largely ineffective against short-term predation in closed aquatic environments. These findings provide fundamental insights into the molecular basis of predation in ciliates and suggest the potential utility of C. vorax in biocontrol applications targeting pathogenic ciliates.

Ciliophora↗
PubMed2026

Outer membrane changes enable evolutionary escape from bacterial predation.

Antimicrobial resistance (AMR) is a threat to modern medicine. To combat AMR pathogens, natural predators like bacteriophages and predatory bacteria have gained interest recently. Predatory bacterium Bdellovibrio bacteriovorus is ubiquitous and has a broad prey range. It is particularly potent at killing many AMR Gram-negative bacterial pathogens featured on the WHO priority list. However, it is currently unclear whether prey bacteria can evolve genetically-determined resistance against predation by B. bacteriovorus. Here, we show that the model bacterium Escherichia coli K-12 consistently evolves resistance against B. bacteriovorus during experimental evolution. Selection for resistance scaled positively with predation pressure and was widespread after two cycles of predator exposure. Similar to antibiotics, predation resistance was costly, manifesting in a trade-off between predation resistance and fitness in the absence of predators. Genetic analysis combined with proteomics identified mutations that lead to the down-regulation of the outer membrane porin OmpF as a common resistance mechanism. In addition, a rarer mutation in cell envelope lipopolysaccharide-modifying enzyme WaaF also conferred predation resistance, likely by a pleiotropic effect, which included OmpF down regulation. While our study uncovers evolutionary and mechanistic aspects of prey escape from predation, it also highlights that the high cost of resistance reflects a handicap for the pathogen and can thus be exploited to increase treatment sustainability. Altogether, our work generates essential knowledge in ecologically important predator-prey interactions and can advance predatory bacteria as "living antibiotics" to combat AMR.

Bdellovibrio bacteriovorus↗
PubMed2026

Quantifying the control laws governing terminal attack in lions.

Intercepting an evasive, maneuvering target is among the most computationally demanding tasks a predator performs: in the terminal phase of a chase, it must continuously convert sensory information about the target into steering and speed commands, subject to its own biomechanical limits. How terrestrial predators solve this in real time has remained difficult to quantify. Here, we combine drone videography with AI-based markerless pose estimation to reconstruct the kinematics of 67 lion (Panthera leo) attacks on a mechanized lure programmed to move unpredictably. Lion steering is described by a combination of proportional navigation and proportional pursuit, which is a mixed guidance law previously identified only in the aerial pursuit of Harris's hawks (Parabuteo unicinctus), and speed is regulated within a defined kinematic envelope during turns, which declines at close range where the cost of overshooting is greatest. These findings reveal shared guidance principles across aerial and terrestrial pursuit, thus providing a quantitative framework for comparing pursuit strategies across species.

computational ethology↗