Search results for "PREY"

Complementary methods assessing short and long-term prey of a marine top predator ‒ Application to the grey seal-fishery conflict in the Baltic Sea.

2019

The growing grey seal (Halichoerus grypus) population in the Baltic Sea has created conflicts with local fisheries, comparable to similar emerging problems worldwide. Adequate information on the foraging habits is a requirement for responsible management of the seal population. We investigated the applicability of available dietary assessment methods by comparing morphological analysis and DNA metabarcoding of gut contents (short-term diet; n = 129/125 seals, respectively), and tissue chemical markers i.e. fatty acid (FA) profiles of blubber and stable isotopes (SIs) of liver and muscle (mid- or long-term diet; n = 108 seals for the FA and SI markers). The methods provided complementary inf…

Behavioural responses of two phytoseiid mites (Parasitiformes, Phytoseiidae) to different densities of the prey Tetranychus urticae Koch (Acariformes…

2008

Food resource partitioning between two sympatric temperate wrasses

2017

The present study analysed two sympatric wrasses, Thalassoma pavo and Coris julis, with similar sizes and morphologies, that are widespread in the reef habitats of the Mediterranean and the eastern Atlantic coast. Ocean warming has induced the northward movement of T. pavo, whereas C. julis has been moving to deeper habitats. In addition, under conditions of high slope of the sea bottom, T. pavo occupies shallow habitats and C. julis is in greater abundance in deeper habitats. By investigating stomach contents and prey availability in the benthos, we assessed whether the two wrasses exploit food resources by choosing different prey within the same habitat both under co-existence and segreg…

Integrity of predator assemblages controls the abundanceof the alien crab Percnon gibbesi

2016

Ecosystem resistance to species invasion is considered to be related to the abundance and diversity of native species (i.e. diversity-resistance hypothesis). In particular, the integrity of predator assemblages may enhance the control of prey populations through direct and indirect interactions (e.g.: different predation strategies by different predators, facilitative interactions among predators). Depletion of predators due to overfishing is therefore expected to enhance the abundance and ultimately the spread of alien prey species. Manipulative field experiments were performed to evaluate the effects of different abundance and diversity of predator assemblages on the invasion success of t…

Type I keratin cDNAs from the rainbow trout: independent radiation of keratins in fish

2002

Five different type I keratins from a teleost fish, the rainbow trout Oncorhynchus mykiss, have been sequenced by cDNA cloning and identified at the protein level by peptide mass mapping using MALDI-MS. This showed that the entire range of type I keratins detected biochemically in this fish has now been sequenced. Three of the keratins are expressed in the epidermis (subtype Ie), whereas the other two occur in simple epithelia and mesenchymal cells (subtype Is). Among the Is keratins is an ortholog of human K18; the second Is polypeptide is clearly distinct from K18. We raised a new monoclonal antibody (F1F2, subclass IgG1) that specifically recognizes trout Is keratins, with negative react…

Maintenance, feeding and growth of Carybdea marsupialis (Cnidaria: Cubozoa) in the laboratory

2013

9 pages, 5 figures, 1 table

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 …

Comparison of different cooperation strategies in the prey-predator problem

2006

The paper describes two cooperating strategies among several homogeneous agents to reach a given target. In our case we used the prey-predators paradigm in which a set of agents (predators) have the purpose to reach a target (prey). The problem is addressed as an optimization problem that has been faced with two different algorithms (a genetic algorithm and a particle swam optimization algorithm). The two approaches are evaluated by using a simulator for each strategy and the results show that the strategies are very different in terms of prey-predator successes. Genetic algorithm can be used by the prey to solve at the best the problem to reach the lair, otherwise the Particle Swarm Optimi…

Comparative morphology of the postpharyngeal gland in the Philanthinae (Hymenoptera, Crabronidae) and the evolution of an antimicrobial brood protect…

2015

Background Hymenoptera that mass-provision their offspring have evolved elaborate antimicrobial strategies to ward off fungal infestation of the highly nutritive larval food. Females of the Afro-European Philanthus triangulum and the South American Trachypus elongatus (Crabronidae, Philanthinae) embalm their prey, paralyzed bees, with a secretion from a complex postpharyngeal gland (PPG). This coating consists of mainly unsaturated hydrocarbons and reduces water accumulation on the prey’s surface, thus rendering it unfavorable for fungal growth. Here we (1) investigated whether a North American Philanthus species also employs prey embalming and (2) assessed the occurrence and morphology of …

Effect of pollens and preys on various biological parameters of the generalist mite Cydnodromus californicus

2009

The generalist phytoseiid mite Cydnodromus californicus (McGregor) (Mesostigmata Phytoseiidae) is considered a very important biocontrol agent of the spider mite Tetranychus urticae Koch both in greenhouses and field. Its capacity to feed alternative foods allows the increase of the population in field, even when the primary prey is not available. To investigate the effect of various alternative food substances present in the Mediterranean agroecosystems on the biological parameters of C. californicus, laboratory trials were carried out using 17 pollens and 3 preys. As it was expected, T. urticae was the best food for both the postembryonic development and the oviposition rate (100% of atta…