Search results for "Predation"
showing 10 items of 589 documents
Data from: Conjugation is necessary for a bacterial plasmid to survive under protozoan predation
2016
Horizontal gene transfer by conjugative plasmids plays a critical role in the evolution of antibiotic resistance. Interactions between bacteria and other organisms can affect the persistence and spread of conjugative plasmids. Here we show that protozoan predation increased the persistence and spread of the antibiotic resistance plasmid RP4 in populations of the opportunist bacterial pathogen Serratia marcescens. A conjugation-defective mutant plasmid was unable to survive under predation, suggesting that conjugative transfer is required for plasmid persistence under the realistic condition of predation. These results indicate that multi-trophic interactions can affect the maintenance of co…
Mechanisms of population declines in boreal forest grouse
2007
Gilbert Ludwig tutki väitöskirjassaan, miksi kanalinnut ovat vähentyneet talousmetsissä. Suomen metsäkanalintukannat ovat vähentyneet merkittävästi viimeisen 40 vuoden ajan. Pesiin ja poikasiin kohdistuvaa saalistusta on pidetty tärkeimpänä syynä kanalintukantojen laskuun. Hakkuiden ja nuorten metsien osuuden lisääntymisen on katsottu lisänneen myyräkantoja ja niitä syöviä petoja, kuten kettuja, lisäten näin myös kanalintujen pesiin ja poikasiin kohdistuvaa saalistusta. Vuosikymmenten aikana laskenut poikastuotto on keskeisessä roolissa kanalintukantojen laskussa. - Ainakaan teerellä vuotuinen aikuiskuolleisuus ei ole lainkaan lisääntynyt. Hengissäsäilyminen on päinvastoin jopa parantunut, …
OBSERVATIONS ON THE BIOLOGY OF A PREDATORY NEMATODE BELONGING TO DIPLOGASTERIDAE
2011
The use of predatory nematodes as biological control agents of phytoparasitic nematodes has been re-evaluated only recently. To be effective, predatory nematodes should be easy to grow, cheap, and available on a commercial scale. In addition, they must show a reproductive rate sufficient to sustain a high population density and a significant longevity and stability for storage. The predators are not phytopathogenic nematodes, and among the positive outcomes of their introduction are remarkable their environment compatibility and safety for other non-target organisms, as well as the ability to search for prey. These features are present in Diplogasteridae. Their adaptability enables them to …
Evidence of energy and nutrient transfer from invasive pink salmon (Oncorhynchus gorbuscha) spawners to juvenile Atlantic salmon (Salmo salar) and br…
2021
Recent large influxes of non‐native Pacific pink salmon (Oncorhynchus gorbuscha) to North European rivers have raised concern over their potential negative impacts on native salmonids and recipient ecosystems. The eggs and carcasses of semelparous pink salmon may provide a significant nutrient and energy subsidy to native biota, but this phenomenon has not been widely documented outside the species' native distribution. We analysed the stomach contents and stable isotope values (δ15N and δ13C) in muscle and liver tissues of juvenile Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) to determine whether these native salmonids utilise marine‐derived nutrients and energy provided by…
Diversifying crop rotations with temporary grasslands: potentials for weed management and farmland biodiversity
2010
Fruchtfolgen können dazu dienen, die kontinuierliche Selektion von Unkrautarten zu verhindern, die an eine bestimmte Kultur angepasst sind. Dies könnte dem Unkrautmanagement, der Einsparung von Herbiziden, und der Biodiversität dienen. Heutige, sehr einfache Furchtfolgen könnten durch mehrjährige Futterkulturen diversifiziert werden. Die Einflüsse solcher mehrjähriger Kulturen auf Unkräuter wurden in vier Ansätzen untersucht : 1) Vegetationsaufnahmen auf 632 Feldern in Westfrankreich zeigten, dass die Unkrautzusammensetzung zwischen mehrjährigen Futterkulturen und einjährigen Kulturen stark variiert. Der Vergleich von Feldern vor, während und nach mehrjährigen Futterkulturen legte nahe, das…
Data from: Deceiving predators: linking distraction behavior with nest survival in a ground-nesting bird
2016
Individual behavior that minimizes predation risk is favored by natural selection. Ground-nesting birds employ different defensive behaviors as part of their antipredator strategies because they nest where a wide range of predators have access. We investigated the influence of distraction displays on breeding success in the Kentish Plover, Charadrius alexandrinus, in order to explore the role of the defensive behavior on nest survival. We quantified the intensity of defensive behavior of adult plovers in response to nest disturbance caused by an approaching researcher, by ranking display types according to the intensity and exposure to predation. We also examined sex differences in nest def…
Volatile compounds released by disturbed and undisturbed adults of Anchomenus dorsalis (Coleoptera, Carabidae, Platynini) and structure of the pygidi…
2011
Volatile compounds produced by adults of Anchomenus dorsalis under undisturbed and disturbed conditions were investigated with an all-glass aeration apparatus. GC-MS analysis of the crude extracts from undisturbed and disturbed adults highlighted four major volatile compounds, undecane, heneicosane, Z-9 tricosene and tricosane, of which significantly more undecane was released by disturbed adults compared to undisturbed beetles. The pygidial glands of adults of A. dorsalis were investigated using light and Transmission Electron Microscopy (TEM). Each gland showed dense aggregates of secretory cells organized into visually distinct lobes; a long collecting canal that drains the secretion tow…
Hard to catch: Experimental evidence supports evasive mimicry
2021
Most research on aposematism has focused on chemically defended prey, but the signalling difficulty of capture remains poorly explored. Similar to classical Batesian and Müllerian mimicry related to distastefulness, such ‘evasive aposematism' may also lead to convergence in warning colours, known as evasive mimicry. A prime candidate group for evasive mimicry areAdelphabutterflies, which are agile insects and show remarkable colour pattern convergence. We tested the ability of naive blue tits to learn to avoid and generalizeAdelphawing patterns associated with the difficulty of capture and compared their response to that of birds that learned to associate the same wing patterns with distast…
Lake size and fish diversity determine resource use and trophic position of a top predator in high-latitude lakes
2015
Prey preference of top predators and energy flow across habitat boundaries are of fundamental importance for structure and function of aquatic and terrestrial ecosystems, as they may have strong effects on production, species diversity, and food-web stability. In lakes, littoral and pelagic food-web compartments are typically coupled and controlled by generalist fish top predators. However, the extent and determinants of such coupling remains a topical area of ecological research and is largely unknown in oligotrophic high-latitude lakes. We analyzed food-web structure and resource use by a generalist top predator, the Arctic charr Salvelinus alpinus (L.), in 17 oligotrophic subarctic lakes…
The evolution and ecology of multiple antipredator defences
2023
Prey seldom rely on a single type of antipredator defence, often using multiple defences to avoid predation. In many cases, selection in different contexts may favour the evolution of multiple defences in a prey. However, a prey may use multiple defences to protect itself during a single predator encounter. Such “defence portfolios” that defend prey against a single instance of predation are distributed across and within successive stages of the predation sequence (encounter, detection, identification, approach (attack), subjugation and consumption). We contend that at present, our understanding of defence portfolio evolution is incomplete, and seen from the fragmentary perspective of speci…