scholarly journals Signalling with a cryptic trait: the regularity of barred plumage in common waxbills

2016 ◽  
Vol 3 (5) ◽  
pp. 160195 ◽  
Author(s):  
Cristiana I. J. Marques ◽  
Helena R. Batalha ◽  
Gonçalo C. Cardoso

Sexual signals often compromise camouflage because of their conspicuousness. Pigmentation patterns, on the contrary, aid in camouflage. It was hypothesized that a particular type of pattern—barred plumage in birds, whereby pigmented bars extend across feathers—could simultaneously signal individual quality, because disruptions of these patterns should be perceptually salient at close range and help assess plumage condition. Here we show that common waxbills ( Estrilda astrild ), which have extensive barred plumage, have more regular patterns as adults than as juveniles, and that adult males have more regular patterns than females. Both these differences are indicative of sexual signalling in species with conventional sex roles. More regular barred plumage was related to better body condition in adult males. Colour ornamentation traits were also related to aspects of quality, either the same as barred plumage (body condition) or a different one (good feather development), supporting both the ‘redundant message’ and the ‘multiple message’ hypotheses for the coexistence of multiple sexual signals. Although receiver responses to the regularity of barred plumage were not studied here, research on other species has shown that barred plumage can mediate social interactions. We conclude that using barred plumage as a signal of quality helps circumvent the functional compromise between camouflage and communication.

2020 ◽  
Vol 16 (4) ◽  
pp. 20200001
Author(s):  
Thomas E. White

Colourful ornaments often communicate salient information to mates, and theory predicts covariance between signal expression and individual quality. This has borne out among pigment-based signals, but the potential for ‘honesty’ in structural coloration is unresolved. Here, I synthesized the available evidence to test this prediction via meta-analysis and found that, overall, the expression of structurally coloured sexual signals is positively associated with individual quality. The effects varied by the measure of quality, however, with body condition and immune function reliably encoded across taxa, but not age nor parasite resistance. The relationship was apparent for both the colour and brightness of signals and was slightly stronger for iridescent ornaments. These results suggest diverse pathways to the encoding and exchange of information among structural colours while highlighting outstanding questions as to the development, visual ecology and evolution of this striking adornment.


Author(s):  
Thomas E. White

AbstractOrnamental colouration often communicates salient information to mates, and theory predicts covariance between signal expression and individual quality. This has borne out among pigment-based signals, but the potential for ‘honesty’ in structural colouration is unresolved. Here I synthesised the available evidence to test this prediction via meta-analysis and found that, overall, the expression of structurally coloured sexual signals is positively associated with individual quality. The effects varied by measure of quality, however, with body condition and immune function reliably encoded across taxa, but not age nor parasite resistance. The relationship was apparent for both the colour and brightness of signals and was slightly stronger for iridescent ornaments. These results suggest diverse pathways to the encoding and exchange of information among structural colours, while highlighting outstanding questions as to the development, visual ecology, and evolution of this striking adornment.


2012 ◽  
Vol 8 (3) ◽  
pp. 423-425 ◽  
Author(s):  
Mari Pölkki ◽  
Indrikis Krams ◽  
Katariina Kangassalo ◽  
Markus J. Rantala

In many species of animals, individuals advertise their quality with sexual signals to obtain mates. Chemical signals such as volatile pheromones are species specific, and their primary purpose is to influence mate choice by carrying information about the phenotypic and genetic quality of the sender. The deleterious effects of consanguineous mating on individual quality are generally known, whereas the effect of inbreeding on sexual signalling is poorly understood. Here, we tested whether inbreeding reduces the attractiveness of sexual signalling in the mealworm beetle, Tenebrio molitor , by testing the preferences for odours of inbred and outbred (control) individuals of the opposite sex. Females were more attracted to the odours produced by outbred males than the odours produced by inbred males, suggesting that inbreeding reduces the attractiveness of male sexual signalling. However, we did not find any difference between the attractiveness of inbred and outbred female odours, which may indicate that the quality of females is either irrelevant for T. molitor males or quality is not revealed through female odours.


1980 ◽  
Vol 58 (3) ◽  
pp. 461-463 ◽  
Author(s):  
R. E. Salter

Social interactions in walrus herds of mixed sex and age composition were recorded at a haul-out site on the east coast of Bathurst Island, N.W.T., during July–August 1977. Most walruses maintained body contact with at least one other walrus while hauled out on land; herds were usually circular in shape. Adult males, adult females, and immatures all displaced other walruses, and thus entered herds, by jabbing with the tusks. Dominance during agonistic interactions was related to relative tusk length and sex and age of interactants. Behaviour of walruses on land suggested an energetic advantage in mutual body contact, which would be maximized by occupation of interior positions within herds.


2020 ◽  
Author(s):  
Marlen Fröhlich ◽  
Natasha Bartolotta ◽  
Caroline Fryns ◽  
Colin Wagner ◽  
Laurene Momon ◽  
...  

Abstract From early infancy, human face-to-face communication is “multimodal”, comprising a plethora of interlinked articulators and sensory modalities. Although there is also growing evidence for this in nonhuman primates, the functions of integrating articulators (i.e. multiplex or multi-articulator acts) and channels (i.e. multimodal or multi-sensory acts) remain poorly understood. Here, we studied close-range social interactions within and beyond mother-infant pairs of Bornean and Sumatran orang-utans living in wild and captive settings, to examine to what extent species, setting and recipient-dependent factors affected the use of and responses to multi-sensory as well as multi-articulator communication. Results showed that both multi-sensory and multi-articulatory acts were more effective at eliciting responses (i.e. “apparently satisfactory outcomes”) than their respective uni-component parts, and generally played a larger role in wild populations. However, only multi-articulator acts were used more when the presumed goal did not match the dominant outcome for a specific communicative act, and were more common among non-mother-infant dyads and Sumatrans across settings. We suggest that communication through multiple sensory channels primarily facilitates effectiveness, whereas a flexible combination of articulators is relevant when social tolerance and interaction outcomes are less predictable. These different functions underscore the importance of distinguishing between these forms of multi-component communication.


2019 ◽  
Vol 31 (2) ◽  
pp. 383-392 ◽  
Author(s):  
Liisa Hämäläinen ◽  
Johanna Mappes ◽  
Rose Thorogood ◽  
Janne K Valkonen ◽  
Kaijamari Karttunen ◽  
...  

Abstract 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. We next investigated whether the response threshold influenced the consumption of defended prey during avoidance learning by presenting birds with novel palatable and defended prey in a random sequence until they refused to attack defended prey. We predicted that individuals with taste response thresholds at lower concentrations would consume fewer defended prey before rejecting them, but found that the response threshold had no effect on the birds’ foraging choices. Instead, willingness to consume defended prey was influenced by the birds’ body condition. This effect was age- and sex-dependent, with adult males attacking more of the defended prey when their body condition was poor, whereas body condition did not have an effect on the foraging choices of juveniles and females. Together, our results suggest that even though taste perception might be important for recognizing prey toxicity, other factors, such as predators’ energetic state, drive the decisions to consume chemically defended prey.


2012 ◽  
Vol 126 (1) ◽  
pp. 6 ◽  
Author(s):  
Spencer G. Sealy ◽  
Harry R. Carter

From 1979 through 2009, 81 records of long-distance vagrancy in the Long-billed Murrelet (Brachyramphus perdix) in North America south of Alaska were examined to assess body condition and survival after first observation. Sixty-one records were of live birds, of which 38 (62.3%) were discovered at sea along the west coast of North America, 18 (29.5%) were encountered inland, and 5 (8.2%) were encountered along the Atlantic coast. Fifteen of the 20 individuals salvaged (19 adults, 1 juvenile) were discovered on lake shores (75.0%) and the other 5 (25.0%) on marine coasts; 85.0% were dead when initially found (15 dead, 2 shot), and 3 (15.0%) were moribund (2 died within one day, 1 later released). Of 10 sexed individuals, 5 were adult males, 4 were adult females, and 1 was a juvenile female. Eight of 10 murrelets observed foraging were diving on lakes, but 2 others surfaced with fish; two species of common freshwater fish were removed from stomachs of 2 birds shot by hunters. Most birds (72.1%, n = 61) disappeared after one observation, which suggests survival and moving on; one bird stayed at the same location for at least 25 days before disappearing. Dead or dying Long-billed Murrelets found on shorelines of fresh water may have been too emaciated to regain lost mass after arrival—they weighed less than those shot, presumably because they were not able to locate prey or too weak to capture it. Survival for weeks or longer on freshwater stopover sites better explains how Long-billed Murrelets move across North America, with some reaching the Atlantic Ocean. Long-surviving vagrants may establish a new breeding population of Long-billed Murrelet on the west coast of North America.


1981 ◽  
Vol 113 (7) ◽  
pp. 645-650 ◽  
Author(s):  
P. T. Oester ◽  
J. A. Rudinsky ◽  
L. C. Ryker

AbstractMature male Pseudohylesinus nebulosus (LeConte) walking on Douglas-fir logs were strongly arrested and stridulated at a female gallery or artificial galleries with female frass, but not at artificial galleries without frass. This response diminished after the female had accepted a male in the gallery. Mature males emitted distinctive chirps for stress, attraction, and rivalry, all of which were different from chirps of immature males, and pushed intruding males from the gallery. In contrast, reproductively immature adult males were only weakly arrested both at artificial galleries and those of feeding females, and were not aggressive toward other males. Only stress chirps of immature males were distinguishable from chirps in other contexts. These observations suggest that adult reproductive maturation includes development of close-range olfactory and acoustic signals and territorial behavior.


Oecologia ◽  
2005 ◽  
Vol 143 (3) ◽  
pp. 365-376 ◽  
Author(s):  
Peter Blums ◽  
James D Nichols ◽  
James E. Hines ◽  
Mark S. Lindberg ◽  
Aivars Mednis

Behaviour ◽  
1996 ◽  
Vol 133 (11-12) ◽  
pp. 827-845 ◽  
Author(s):  
A.H. Harcourt ◽  
K.J. Stewart

We investigate the social significance of the within group ('close') calls of gorillas by examining correlates of calling with dominance rank and with relatedness of adults, and by examining whether the outcomes of interactions between adults differ depending on the calls given during the interactions. In two wild gorilla groups, the majority of adults give most of their calls when near another adult and fully in sight of them. Thus gorillas' use 'close' calls as more than mere contact calls. An adult gorilla's use of 'close' calls correlates with its own and with its partner's dominance rank, with effects being most obvious for the most dominant animals, the fully adult males. Thus the proportion of 'double grunts', the most common 'close' call, in an individual's repertoire correlated consistently with dominance rank; all non-silverback adults gave a higher percent of double grunts in the presence of subordinates than they did near dominant animals; individuals were most likely to give 'non-syllabled' grunts in the adult male's presence; and they consistently exchanged calls at a higher rate with the adult males than with other group members. An adult's type of calls did not obviously differ depending on whether their neighbour was kin or non-kin, but kin were overall more likely to give calls in the presence of kin, and to exchange calls with kin than with non-kin, although the association was not consistent throughout the two years of the study. With regard to the consequences of calling, subordinates were less likely to be feeding one minute after an approach by a fully adult male during which calls were exchanged than during silent approaches. In contrast to findings from studies of some other species, calling did not correlate with duration of grooming. We suggest that, among other functions, gorillas' 'close' calls mediate social interactions. One form of calls, 'non-syllabled' calls, are interpretable as appeasement signals. The broadest interpretation of the 'double grunt' is that it is an exaggerated announcement of presence, whose function is to attract attention to the caller, and to signal conditional future activity.


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