Search results for "Predatory"

Co-mimics have a mutualistic relationship despite unequal defences

2007

Defensive mimicry, where species have evolved to resemble others in order to evade predators, is quite common in the animal kingdom. The two extremes of the mimicry spectrum are known as 'batesian' and 'mullerian'. Batesian mimics develop signals — visual cues for instance — that are similar to those of species being mimicked, but stop short of adopting the attribute that makes it unprofitable prey to predators. Mullerian mimics both resemble the model species and share the anti-predation attribute — by being dangerous or unpalatable. These different types of mimic were identified a century ago, but the dynamics of mimicry between unequally defended prey remain unresolved. In an experiment …

Strong antiapostatic selection against novel rare aposematic prey

2001

The evolution of aposematism, a phenomenon where prey species conspicuously advertise their unprofitability to predators, is puzzling. How did conspicuousness evolve, if it simultaneously increased the likelihood of an inexperienced predator to detect the prey and presumably kill it? Antiapostatic selection, where rare prey is predated relatively more often, is considered as another major difficulty for aposematism to evolve. However, the risk of being conspicuous in low frequencies has not been experimentally tested. We designed an experiment to test how frequency (4%, 12%, 32%) of conspicuous aposematic prey and its dispersion type (solitary vs. aggregated) affect an initial predation ri…

Selection for cryptic coloration in a visually heterogeneous habitat.

2001

We studied selection by predators for cryptic prey coloration in a visually heterogeneous habitat that consists of two microhabitats. It has been suggested that the probability of escaping detection in such habitats might be optimized by maximizing crypsis in one of the microhabitats. However, a recent model indicates that a coloration that compromises the requirements of different microhabitats might sometimes be the optimal solution. To experimentally study these hypotheses, we allowed great tits (Parus major L.) to search for artificial prey items in two different microhabitats (background boards): small patterned and large patterned. On each board there was one prey item that was either…

Multiple benefits of gregariousness cover detectability costs in aposematic aggregations

2001

Understanding the early evolution of aposematic (warning) coloration has been a challenge for scientists, as a new conspicuous morph in a population of cryptic insects would have a high predation risk and would probably die out before local predators learnt to avoid it1,2,3,4. Fisher5 presented the idea of aggregation benefit through the survival of related individuals; however, his theory has been strongly debated6,7,8 as the mechanisms that favour grouping have never been explored experimentally with the incorporation of detectability costs. Here we create a comprehensive ‘novel world’ experiment with the great tit (Parus major) as a predator to explore simultaneously the predation-relate…

John Bates Clark on trusts: New light from the Columbia archives

2005

Public concern over the so called “trust problem” in the United States between the end of the nineteenth century and 1914, the year of the passage of the Clayton and Federal Trade Commission (FTC) Acts, was reflected in the considerable contemporary literature on the subject. Not surprisingly, professional economists actively participated in this debate. Their thinking directly and indirectly influenced the legislation of 1914 in a way that cannot be said of the Sherman Act of 1890 (Mayhew 1998). A survey of the most important of these professional writings shows that, among the several voices animating the discussion, John Bates Clark's was perhaps the most influential. In this connection,…

“Think. Check. Submit.” to avoid predatory publishing

2018

El plagio y las revistas depredadoras como amenaza a la integridad cientifica

2019

Resumen: Este artículo propone un análisis del concepto del plagio con la finalidad de mostrar el amplio espectro de manifestaciones que pueden ser consideradas como tal al incurrir en una transgresión de la propiedad intelectual, realizada con el ánimo de engañar sobre la verdadera contribución de los autores y sobre la originalidad y novedad de la información.Describe las distintas circunstancias en las que se incurre en un plagio intencional y el daño que esta mala conducta ocasiona en la credibilidad de un sistema científico, en el que el crédito de autoría es el fundamento de la carrera académica, del prestigio del autor en la comunidad científica y la base para la financiación de la i…

Fish-seastar facilitation leads to algal forest restoration on protected rocky reefs

2015

AbstractAlthough protected areas can lead to recovery of overharvested species, it is much less clear whether the return of certain predator species or a diversity of predator species can lead to re-establishment of important top-down forces that regulate whole ecosystems. Here we report that the algal recovery in a Mediterranean Marine Protected Area did not derive from the increase in the traditional strong predators, but rather from the establishment of a previously unknown interaction between the thermophilic fish Thalassoma pavo and the seastar Marthasterias glacialis. The interaction resulted in elevated predation rates on sea urchins responsible for algal overgrazing. Manipulative ex…

THE EFFECT OF ALTERNATIVE PREY ON THE DYNAMICS OF IMPERFECT BATESIAN AND MÜLLERIAN MIMICRIES

2004

Both Batesian and Müllerian mimicries are considered classical evidence of natural selection where predation pressure has, at times, created a striking similarity between unrelated prey species. Batesian mimicry, in which palatable mimics resemble unpalatable aposematic species, is parasitic and only beneficial to the mimics. By contrast, in classical Müllerian mimicry the cost of predators' avoidance learning is shared between similar unpalatable co-mimics, and therefore mimicry benefits all parties. Recent studies using mathematical modeling have questioned the dynamics of Müllerian mimicry, suggesting that fitness benefits should be calculated in a way similar to Batesian mimicry; that i…

Prey community structure affects how predators select for Müllerian mimicry

2012

Müllerian mimicry describes the close resemblance between aposematic prey species; it is thought to be beneficial because sharing a warning signal decreases the mortality caused by sampling by inexperienced predators learning to avoid the signal. It has been hypothesized that selection for mimicry is strongest in multi-species prey communities where predators are more prone to misidentify the prey than in simple communities. In this study, wild great tits ( Parus major ) foraged from either simple (few prey appearances) or complex (several prey appearances) artificial prey communities where a specific model prey was always present. Owing to slower learning, the model did suffer higher mort…