Search results for "predators."

Evidence of endothermy in the extinct macropredatory osteichthyan Xiphactinus audax (Teleostei, Ichthyodectiformes)

2020

Xiphactinus audax is the largest macropredatory osteichthyan ever known (Everhart et al., 2010). Some of the largest specimens exceed 5 m in total length, although the discovery of a few large, isolated teeth suggests that this teleost could reach even larger body sizes (Vavrek et al., 2016, and references therein). Fossil remains of this species have only been reported from the Upper Cretaceous of North America, across the Western Interior Basin (Schwimmer et al., 1997; Vavrek et al., 2016). The discovery of several virtually complete individuals in this area has provided valuable information about the anatomy, the dimensions, and the ecology of this species (Cope, 1872; Bardack, 1965). Xi…

Howl variation across Himalayan, North African, Indian, and Holarctic wolf clades: tracing divergence in the world’s oldest wolf lineages using acous…

2017

Abstract Vocal divergence within species often corresponds to morphological, environmental, and genetic differences between populations. Wolf howls are long-range signals that encode individual, group, and subspecies differences, yet the factors that may drive this variation are poorly understood. Furthermore, the taxonomic division within the Canis genus remains contended and additional data are required to clarify the position of the Himalayan, North African, and Indian wolves within Canis lupus. We recorded 451 howls from the 3 most basal wolf lineages—Himalayan C. lupus chanco—Himalayan haplotype, North African C. lupus lupaster, and Indian C. lupus pallipes wolves—and present a howl ac…

Predators' consumption of unpalatable prey does not vary as a function of bitter taste perception

2020

Many prey species contain defensive chemicals that are described as tasting bitter. Bitter taste perception is, therefore, assumed to be important when predators are learning about prey defenses. However, it is not known how individuals differ in their response to bitter taste, and how this influences their foraging decisions. We conducted taste perception assays in which wild-caught great tits (Parus major) were given water with increasing concentrations of bitter-tasting chloroquine diphosphate until they showed an aversive response to bitter taste. This response threshold was found to vary considerably among individuals, ranging from chloroquine concentrations of 0.01 mmol/L to 8 mmol/L.…

Biodiversity change after climate-induced ice-shelf collapse in the Antarctic

2011

Julian Gutt ... et al. -- 10 pages, 5 figures, 1 table, supplementary data https://doi.org/10.1016/j.dsr2.2010.05.024

Key carabid species drive spring weed seed predation of Viola arvensis

2020

Social information use about novel aposematic prey is not influenced by a predator’s previous experience with toxins

2019

Aposematism is an effective antipredator strategy. However, the initial evolution and maintenance of aposematism are paradoxical because conspicuous prey are vulnerable to attack by naive predators. Consequently, the evolution of aposematic signal mimicry is also difficult to explain. The cost of conspicuousness can be reduced if predators learn about novel aposematic prey by observing another predator's response to that same prey. On the other hand, observing positive foraging events might also inform predators about the presence of undefended mimics, accelerating predation on both mimics and their defended models. It is currently unknown, however, how personal and social information combi…

Geographic mosaic of selection by avian predators on hindwing warning colour in a polymorphic aposematic moth

2020

AbstractWarning signals are predicted to develop signal monomorphism via positive frequency-dependent selection (+FDS) albeit many aposematic systems exhibit signal polymorphism. To understand this mismatch, we conducted a large-scale predation experiment in four locations, among which the frequencies of hindwing warning coloration of aposematic Arctia plantaginis differ. Here we show that selection by avian predators on warning colour is predicted by local morph frequency and predator community composition. We found +FDS to be strongest in monomorphic Scotland, and in contrast, lowest in polymorphic Finland, where different predators favour different male morphs. +FDS was also found in Geo…

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…

Detection of protection benefits for predatory fishes depends on census methodology

2021

Marine protected areas (MPAs) are used as fisheries management and conservation tools. Well-enforced no-take zones allow the rebuilding of natural populations of exploited species; however, there is still controversy on the role of buffer zones. The effectiveness of MPAs could be underestimated, as fish population assessments depend largely on traditional methodologies that have difficulties in detecting predatory fish because of their low abundances, their patchy distribution, and their reaction to the presence of divers. The performance of different census methods was compared in assessing the protection benefits for large predatory fishes under different protection levels (i.e. no-take a…

Wolbachia prevalence and diversity in selected riverine predatory beetles (Bembidiini and Paederini)

2018

Despite the many studies on Wolbachia in Coleoptera, data about the prevalence of this bacterium among ground and rove beetles are missing. This study describes Wolbachia distribution and diversity in predatory beetles co-habiting the same environment - submontane river channels. Three species of Paederini (Staphylinidae) and four Bembidiini (Carabidae) were collected from six river catchments of the Carpathians. Wolbachia was absent in three species: Paederidus rubrothoracicus (Goeze), Bembidion decorum (Zenker in Panzer), Bembidion modestum (F.) - but detected in four others. Paederus limnophilus Erichson and Paederidus ruficollis F. were infected at only some sites by different strains o…