Search results for "COLORATION"

Health parameters and sexual signalling in yearling black grouse males (Tetrao tetrix)

2006

Diversité génétique individuelle, différenciation morphologique et comportementale entres les sexes, patterns d'appariement et paramètres démographiq…

2013

Research in avian behavioral ecology is affected by a known bias in favour of temperate species despite the greatest diversity of tropical species and the radically remote natural conditions which make knowledge of temperate species hardly relevant to tropical species.We propose to reduce the lack of information about tropical birds through the study of a socially monogamous species, reproducing and defending an all-purpose territory all year round, the Zenaida dove, Zenaida aurita. We used monitoring data from a population of ringed birds in Barbados for six years. First, we focused on plumage coloration both to ascertain their sexually mono- or dichromatic nature and whether plumage colou…

Méthode de coloration pour l'observation et le comptage des endomycorhises à vésicules et arbuscules sur racines de maïs

2004

Cette méthode permet d'observer et de quantifier les Mycorhizes à Vésicules sur des racines de maïs sous loupe binoculaire (X 60)

THERMOREGULATION CONSTRAINS EFFECTIVE WARNING SIGNAL EXPRESSION

2009

Evolution of conspicuous signals may be constrained if animal coloration has nonsignaling as well as signaling functions. In aposematic wood tiger moth (Parasemia plantaginis) larvae, the size of a warning signal (orange patch on black body) varies phenotypically and genetically. Although a large warning signal is favored as an antipredator defense, we hypothesized that thermoregulation may constrain the signal size in colder habitats. To test this hypothesis, we conducted a factorial rearing experiment with two selection lines for larval coloration (small and large signal) and with two temperature manipulations (high and low temperature environment). Temperature constrained the size and br…

Significance of the dorsal zigzag pattern of Vipera latastei gaditana against avian predators

2005

Summary 1. Aposematism is an antipredatory strategy in which prey animals conspicuously signal their noxiousness to potential predators. This successful strategy is based on avoidance learning of predators. 2. Most species in the viperid genus Vipera have a characteristic dorsal zigzag pattern. It has previously been suggested that the dorsal zigzag pattern of Vipera berus (the adder) has a cryptic function and thus makes the snake less conspicuous to avian predators. However, a recent experiment suggested that the pattern may function as an aposematic signal rather than being cryptic, and therefore induces active avoidance in avian predators. 3. We conducted a field experiment in Donana na…

Tooth discoloration and internal bleaching after the use of ledermix paste with various bleaching agents ? An in vitro study

2018

Background To assess the reversal of discolouration caused by Ledermix using various bleaching agents. Material and Methods Twenty six extracted human mandibular premolars were taken and divided into four groups. Six teeth were divided into three each which are taken as positive and negative controls. The remaining twenty are divided into two groups (n=10). After conventional access preparation, the Ledermix paste was sealed in the pulp chamber for twelve weeks. The paste was removed by a rinse with sodium hypochlorite (NaOCl). Then the pulp chamber was sealed with a mixture of Sodium perborate and distilled water for group 1 and group 2 was sealed with Sodium tetraborate for 1 to 12 weeks.…

Predator mimicry, not conspicuousness, explains the efficacy of butterfly eyespots

2015

Large conspicuous eyespots on butterfly wings have been shown to deter predators. This has been traditionally explained by mimicry of vertebrate eyes, but recently the classic eye-mimicry hypothesis has been challenged. It is proposed that the conspicuousness of the eyespot, not mimicry, is what causes aversion due to sensory biases, neophobia or sensory overloads. We conducted an experiment to directly test whether the eye-mimicry or the conspicuousness hypothesis better explain eyespot efficacy. We used great tits ( Parus major ) as model predator, and tested their reaction towards animated images on a computer display. Birds were tested against images of butterflies without eyespots, wi…

Protective coloration of European vipers throughout the predation sequence

2020

Antipredator adaptations in the form of animal coloration are common and often multifunctional. European vipers (genus Vipera) have a characteristic dorsal zigzag pattern, which has been shown to serve as a warning signal to potential predators. At the same time, it has been suggested to decrease detection risk, and to cause a motion dazzle or flicker-fusion effect during movement. We tested these hypotheses by asking whether (1) the zigzag pattern decreases detection risk and (2) the detection is dependent on the base coloration (grey or brown) or the snake's posture (coiled, basking form or S-shaped, active form). Additionally, (3) we measured the fleeing speed of adders, Vipera berus, an…

Winter male plumage coloration correlates with breeding status in a cooperative breeding species

2007

The function of colored ornaments is usually related to the signaling of individual quality in intra- and intersexual interactions. In cooperative breeding species, where only a fraction of the male population access the breeding status and the other fraction has the option to help breeding pairs, colored traits might provide the females with a reliable information on the quality of potential mate. Males of the cooperative breeding azure-winged magpies (Cyanopica cyanus) display conspicuous blue plumage coloration. Here we explored the role played by structural blue coloration of males and the probability of becoming a breeder or a helper. Birds were trapped during 4 consecutive years, and …

Influences of geographic differentiation in the forewing warning signal of the wood tiger moth in Alaska

2014

Aposematic organisms have warning signals advertising their unpalatability to predators, and because signal efficiency is better in higher densities, positive frequency-dependent selection is expected to select against less common signals. The wood tiger moth (Parasemia plantaginis) occurs across the Holarctic and its conspicuous hindwings serve as warning signals to predators. It also has conspicuous black and white forewing patterns that could act as warning signals, or help to hide the moth by preventing predators from seeing the outline of the moth’s body (a strategy known as disruptive coloration). In Alaska, the predominant forewing pattern changes distinctly between the regions aroun…