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1.
Fluctuating asymmetry (FA) can indicate developmental instability in bilaterally symmetric organisms, and studies have shown
that the degree of asymmetry in male secondary sexual characters influences female mate choice in a number of taxa. In male
Schizocosa ocreata wolf spiders, conspicuous tufts of bristles on the forelegs are a critical component of visual courtship signals, which appear
to play a role in female mate choice. Previous studies have shown that females exhibit reduced receptivity to males with regenerative
asymmetry, a consequence of leg loss and regeneration that causes males to be grossly asymmetric with respect to this important
signaling character. We provide data on the occurrence of FA in the tufts of S. ocreata, and examine further the influence of asymmetry on female mate choice. The distribution of tuft area asymmetry values from
a sample of field-collected males was normal, with a mean value of zero, indicating true FA. For a subset of males measured
directly after field collection and prior to feeding, tuft asymmetry was significantly negatively correlated with measures
of body size (body length) and condition (abdomen volume/cephalothorax width). Receptivity responses of females to visual
signals from live males of similar size varied with the degree of asymmetry in male tufts. Since FA covaries with male body
size and condition, which may also influence behavioral vigor, we used video image manipulation to alter the degree of asymmetry
in tufts of a courting male while holding size and condition constant. Asymmetry treatments represented values within the
range of natural FA variation as well as more extreme values characteristic of regenerative asymmetry. With the confounding
effects of male size, condition, and behavior held constant, female spiders exhibited reduced receptivity responses to all
experimental asymmetric video images relative to a control video stimulus. There were no differences in the frequency of female
receptivity among the various asymmetry treatments, suggesting that discrimination against asymmetry in conspecific male signal
characters is not simply a rejection of extreme phenotypes. Results suggest that asymmetry in a key male secondary character
used in visual signaling, independent of any concomitant behavioral or size factor, is an important criterion in mate choice.
Received: 26 February 1998 / Accepted after revision: 12 September 1998 相似文献
2.
Males of the brush-legged wolf spider, Schizocosa ocreata (Araneae: Lycosidae), possess a conspicuous male secondary sexual character: dark pigmentation and tufts of bristles on the
tibiae of their forelegs. We tested several hypotheses relating to the role of this conspicuous trait in sexual selection.
Triad mating experiments suggest that the tufts do not play an obvious role in the operation of sexual selection by either
male competition or female choice, as there were no significant differences in the mating success of intact and experimentally
shaved males. However, females mated more often with males that initiated courtship first, suggesting that capture of a female’s
attention by male signalling may play a critical role. In behavioral experiments that paired a single male with a female in
arenas that allowed both visual and vibratory signal transmission during courtship, female receptivity did not vary significantly
with the presence or absence of tufts. However, experiments that isolated the visual component of communication (by eliminating
vibratory communication) revealed a significant effect of the presence of tufts: females showed receptivity less often to
males with tufts removed. Female response to visual signals was much greater in S. ocreata than in its sibling congener, Schizocosa rovneri, which lacks male tufts. We hypothesize that the tufts serve to increase the efficacy of visual displays of S. ocreata, as vibratory communication is constrained by the complex leaf litter habitat of some populations. Such environmental constraints
may make visual signalling over distance a critical factor for effective courtship communication, which may in turn strongly
influence male fitness.
Received: 30 September 1994/Accepted after revision: 4 August 1995 相似文献
3.
Leg ornamentation and the efficacy of courtship display in four species of wolf spider (Araneae: Lycosidae) 总被引:1,自引:1,他引:0
This study used both correlative and experimental video playback methods to test the hypothesis that the secondary sexual
traits of male wolf spiders act to increase the efficacy of visual courtship displays. Direct observations of courtship of
several lycosid genera and a review of the literature revealed a significant association between ornamentation and visual
courtship displays. This suggests that the ornamentation may be playing the role of amplifier for a visual display. To test
this hypothesis, male courtship behaviors of four Schizocosa species were experimentally manipulated using video-imaging techniques. Females of species with non-visually displaying,
non-ornamented males (Schizocosa duplex and S. uetzi) did not increase in frequency of receptivity when tufts were added to conspecific males. In a species with a visual display
and foreleg pigmentation (S. stridulans), the addition of foreleg tufts increased female receptivity. In a tufted species (S. crassipes), females tended to decrease their receptivity when male ornamentation was completely removed. In visually displaying species,
ornamentation acts to increase female receptivity, supporting its role as an amplifier of a visual display.
Received: 29 December 1997 / Received in revised form: 23 October 1999 / Accepted: 13 December 1999 相似文献
4.
Pedro P. Olea Fabián Casas Steve Redpath Javier Viñuela 《Behavioral ecology and sociobiology》2010,64(6):927-937
Visual displays are signals that may be selected to increase visibility. Light is a crucial component in the transmission
of visual signals, and white colour is very conspicuous when illuminated by sun and exhibited against darker backgrounds.
Here we tested the hypothesis that orientation of sexual displays in male great bustard (Otis tarda) depends upon position of the sun, i.e., males direct their uplifted white tails towards the sun in order to maximise signal
detectability to distant females. We recorded the orientation of 405 male displays in relation to the sun and to females at
seven leks. Great bustard males signalled towards the sun more often than expected by chance in early morning, although this
pattern was not obvious at other times of day, when males displayed more towards females. Our hypothesis was further supported
by the fact that displays were more directed towards the sun when the sun was most visible. Males were more likely to direct
their displays towards females during the most elaborate components of their courtship display and when there were fewer males
on the lek. Pointing white plumage to the sun may be a behaviour selected in species living in steppe-like open landscapes
if individuals obtain net fitness benefit by increasing the likelihood of mating. 相似文献
5.
G. W. Uetz William J. McClintock Douglas Miller Elizabeth I. Smith Kristina K. Cook 《Behavioral ecology and sociobiology》1996,38(4):253-257
Males of the brush-legged wolf spider Schizocosa ocreata (Hentz) have conspicuously decorated forelegs used in courtship and agonistic displays. Approximately one in five juvenile
males has a missing or regenerating foreleg, and regeneration of a leg lost during development usually results in the absence
of a decorative tuft on that leg. The subsequent asymmetry in this male secondary character significantly decreases success
in both courtship of females and male-male agonistic interactions. Experimental removal of tufts from one leg of previously
successful symmetric males produces similar results. As a test for concomitant behavioral effects, female spiders were shown
video images of a courting male with symmetric tufts and the same video image altered to have asymmetric tufts. Female receptivity
to the asymmetric video image was lower. In contrast to fluctuating asymmetry resulting from developmental instability, leg
tuft asymmetry in S. ocreata most likely arises from a single event during ontogeny – possibly leg loss from an aggressive or predator encounter – and
may serve as a quality indicator in female mate choice.
Received: 27 July 1995/ Accepted after revision: 19 November 1995 相似文献
6.
David L. Clark J. Andrew Roberts Meghan Rector George W. Uetz 《Behavioral ecology and sociobiology》2011,65(6):1237-1247
Animal color patterns often reflect a compromise between natural selection for crypsis or inconspicuousness to predators and
sexual selection for conspicuousness to potential mates. In leaf litter-dwelling wolf spider species like Schizocosa ocreata, body coloration often closely matches the background coloration of a generally brown environment. However, body parts used
in communication should exhibit high contrast against background coloration. We used spectral analysis to examine male and
female S. ocreata for matching and contrasting coloration against leaf litter. Values were plotted in multivariate color space, based on reflectivity
in different frequency ranges. When viewed from above, colors of both males and females overlap with values for dead brown
leaf litter and soil, suggesting cryptic coloration when viewed by potential predators. However, when viewed from a lateral
perspective, both males and females show color values that are polar opposites of litter backgrounds, suggesting higher contrast
when viewed by other spiders. Moreover, male secondary characters used in visual signaling by S. ocreata (tibia brushes) show the highest level of background contrast. These findings suggest that S. ocreata wolf spiders have color patterns that provide both crypsis and background contrast at the same time, depending on receiver
viewing perspective. 相似文献
7.
Visual signal properties often vary greatly between and within individuals in a variety of social contexts. While it is widely known that visual displays emitted by senders can exhibit great variation in efficacy and content, far less is understood whether and how receivers vary in the ability to respond to variability in signal properties, such as motion. Here, we tested for receiver sex differences in visual response latency to motion signals in Sceloporus undulatus lizards. We used a moving robotic lizard model as a visual stimulus to assay response latency in male and female lizards. We measured visual reaction times to slow and fast, up-and-down motions, characteristic of territorial and courtship male motion displays, respectively. We found sex differences in response latency to the two different displays. Specifically, male lizards were faster than females at responding to slow motion produced by the robotic lizard, while female lizards were faster than males at responding to fast motion. These results demonstrate that dynamic visual signals that vary temporally under different social contexts can differ in eliciting a visual response from each sex. Our study highlights that physical differences in dynamic and complex visual signals exhibited during different social contexts (i.e., territorial and courtship contexts) can closely match sex differences in visual responses. 相似文献
8.
Male fitness is often determined by the ability of the male to gain access to multiple mates, although in species that exhibit
sexual cannibalism, males might increase their likelihood of being cannibalized with each encounter. This risk should create
selection for males who are able to perceive potential risks associated with mating encounters. We studied male Schizocosa ocreata wolf spiders to determine whether they use female chemotactile cues (silk, excreta) as indicators of potential risks and
how these cues affected subsequent male courtship behaviors. Female treatments included satiated females vs. starved females,
as well as a treatment where females had recently cannibalized a male S. ocreata. We performed experiments to assess (1) if males use female chemotactile cues to determine potential risks associated with
differing female feeding treatments and alter courtship investment, and 2) how male experience with female chemotactile cues
affected courtship investment in subsequent female encounters. At first encounter, males do not vary courtship investment
(number of bouts, duration, and vigor) with different female feeding treatments. However, male behaviors during subsequent
encounters with female chemotactile cues varied in complex ways, depending on female feeding treatment and male first encounter
experience. These data suggest that male experience impacts perception of female chemical cues and offers the male opportunity
to avoid sexual cannibalism in high-risk situations. 相似文献
9.
Anita Aisenberg Carmen Viera Fernando G. Costa 《Behavioral ecology and sociobiology》2007,62(1):29-35
Sexual selection theory predicts that a higher investment in offspring will turn females into the selective sex, while males
will compete for accessing and courting them. However, there are exceptions to the rule. When males present a high reproductive
investment, sex roles can reverse from typical patterns, turning males into the choosy sex, while females locate males and
initiate courtship. In many spiders, males are smaller than females, wandering in search of sedentary females and maximizing
the number of copulations. In the present study, we present findings on the sand-dwelling wolf spider, Allocosa brasiliensis, evidencing a reversal in typical courtship roles reported for the first time in spiders. Males were bigger than females.
Females located males and initiated courtship. Copulation always occurred in male burrows and took place mainly in long burrows.
Males donated their burrows to the females after copulation, closing the entrance before leaving with female cooperation from
inside. Males would provide females with a secure place for ovipositing, being exposed to predation and diminishing their
future mating possibilities until constructing a new burrow. The cost of vacating the burrow and losing the refuge in an unpredictable
habitat, such as sand dunes, would explain the courtship roles reversal in this spider species. Results turn A. brasiliensis as a promising model for discussing the determinants of sex roles and the pressures that drive their evolution and maintenance.
Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users. 相似文献
10.
Sending color signals to conspecifics may attract predators, leading to opposing selection pressures on the evolution of signal expression and display behavior in animals. The costs of signaling can be reduced, however, because conspicuousness is the combined result of the reflectance spectra of the displayer's color pattern and the spectra of ambient light illuminating the animal. Changes in ambient light can alter conspicuousness, even when chemical and structural color-generating mechanisms remain constant, potentially allowing animals to display their colors most fully in light environments where the benefits are greatest relative to the costs. Using spectroradiometric methods, we determined how light habitat use affects conspicuousness in adult males of the Wire-tailed Manakin Pipra filicauda, a lekking bird species with vivid plumage colors. We studied three aspects of visibility, including properties of the entire color pattern, visual contrast within an individual's plumage and a bird's contrast relative to its visual background. Wire-tailed Manakins usually displayed in forest shade environments, which reduced their conspicuousness at larger viewing distances, while maximizing visual contrast within the plumage color pattern at close viewing distances. Compared to sunspots, ambient light in forest shade reduces the contrast of individual bird colors with the background at close viewing distance. However, background contrast of individual bird colors in the shade was still relatively higher during sunny than during cloudy weather which may explain why males were more active when the sun was not blocked by clouds. Assuming that the visual perceptions of predators and other manakins do not differ from the reflectance patterns we measured, Wire-tailed manakins tend to display in light environments that reduce the conflicts between avoiding long distance detection by predators and displaying conspicuous color signals to visiting females. 相似文献
11.
Summary One of the roles ascribed to spider courtship is that of mate recognition and reproductive isolation. We describe behavioral mechanisms underlying these functions in three species of wandering spiders of the genus Cupiennius (Ctenidae). C. salei and the two sympatric species C. getazi and C. coccineus discriminate conspecifics and heterospecifics in a multistage process which covers three principal phases of courtship: (1) Chemical phase: male spiders initiate vibratory courtship communication less often upon contact with heterospecific than with conspecific female silk. (2) Vibratory phase: females respond with their own vibration less often and with increased delay to the vibratory courtship signals of heterospecific males than to those of conspecific males. (3) Tactile phase: in heterospecific pairings males and females interrupt the contact phase if their courtship has progressed thus far. The product of the probabilities of passing through each of the different stages of courtship is between 0.44 and 0.88 for conspecific pairings, but zero for most heterospecific pairings. This is to a greater extent due to the behavioral barriers of the vibratory and the tactile phase than to that of the chemical phase. Male taxis on tracks of female silk does not depend on the species-specificity of the silk. Female vibrations are not essential for species recognition: males increase their signal rates, orient toward and approach responding females in both con- and heterospecific pairings. Female attacks on males are similar to attacks on prey; males defend themselves with outstretched front legs and are caught and killed by the female in only 5% of the cases. In all phases of courtship, female C. salei are least and female C. getazi most selective. When female C. coccineus and C. getazi are involved in heterospecific pairings no copulation is attempted. In contrast, 13 copulations of C. salei with males of the other two species were observed; egg sacs never resulted from these copulations. Among males, those of C. getazi were least selective. The likelihood of heterospecific pairs passing through all phases of courtship is higher in case of the allopatric than in that of the sympatric species. This finding applies to the courtship as a whole, but not necessarily to each of its phases.Offprint requests to: F.G. Barth 相似文献
12.
Jari J. Ahtiainen Rauno V. Alatalo Raine Kortet Markus J. Rantala 《Behavioral ecology and sociobiology》2006,60(6):826-832
In this study, we provide a piece of experimental evidence that immune function is related to dominance and mating success in wild caught male wolf spiders, Hygrolycosa rubrofasciata. In the mating season, H. rubrofasciata males are actively searching for receptive females, and while searching males often engage in agonistic behavior (i.e., agonistic drumming signals, chases, and fights) with each other. The present results demonstrate that dominant males had higher lytic activities in their hemolymph than subordinates. Lytic activity estimates the concentration of antimicrobial peptides with lysozyme-like activity in hemolymph, which have been shown to play an important role in defense against bacteria, viruses, and fungi. Dominants also had higher courtship drumming rates than subordinates. Moreover, winners in mating competition had higher lytic activities than losers, but this was measured nonindependently of dominance status. Among males with mating failure, there was a moderate negative correlation between encapsulation rate and courtship drumming rate, suggesting that low quality males might not be able to bear the immunological costs of courtship behavior. These results suggest that females might gain immunological benefits by preferring vigorous males. 相似文献
13.
Many species base their choice of mates on multiple signals which provide them with different kinds of information. Choosers
may assess the signals together to evaluate the overall quality of potential mates, but individuals often pay attention to
different signals in different contexts. In Rhinogobius brunneus, a fish displaying exclusive male parental care, females generally prefer males showing larger first dorsal fins (FDF) and
more active courtship displays as mates. Females choosing a mate usually initially assess the FDF and later utilize courtship
for the final decision. In our experiments, females with different hunger states used different signals when selecting mates.
Females in both hunger states preferred males with larger FDF in the first stage. In the second stage, well-fed females showed
highly repeatable choice, whereas poorly fed females responded only to variation in the courtship activity of males. The males
preferred by poorly fed females exhibited significantly higher offspring survival than nonpreferred males. Under conditions
of food shortage, males allocate more energy to future reproduction at the expense of the present brood, and females may prioritize
signals predictive of offspring survivorship over signals reflecting other aspects in male quality to minimize the losses
in direct benefits. We conclude that R. brunneus females may employ information from both signals but dynamically adjust their prioritization of each signal to current conditions
to ensure the choice that is currently most adaptive. 相似文献
14.
Individual variation in female preference for male traits may influence mate choice, especially if benefits and costs of choosiness
vary with the range of available males or reproductive timing. We examined variation in female preference for male leg tuft
size in Schizocosa ocreata (Hentz) wolf spiders with video playback. Dichotomous (simultaneous) choice test experiments included all possible combinations
of four stimuli (i.e., modified versions of the same video male stimulus): average tuft size (control), reduced (−25%), enlarged
(+25%), and no tufts (removed). Females exhibited a directional preference for larger tuft size independent of the nature
of the choice (except for reduced tufts vs no tufts where no difference was seen). Female preference in the short term (over
a period of 4 days) was also highly repeatable for control vs reduced tufts, but not for control vs enlarged tufts. Responses
of females in ‘no-choice’ presentations of a single (control) male stimulus varied with age post-maturity; females were less
receptive in weeks 1 and 2, highly receptive at week 3, and less thereafter. Mated females were least receptive and most aggressive
towards a male stimulus. Females offered choices repeatedly at different ages post-maturity consistently preferred the control
male vs reduced tufts over all 3 weeks but varied in their preference for enlarged tufts vs control male. In the first 2 weeks,
females preferred the enlarged tuft male stimulus, but showed no preference by the third week. Females tested in week 4 showed
no preference in either choice. Results suggest that the potential interaction between female preference for male traits and
female reproductive timing may be a critical consideration in mate choice. 相似文献
15.
The courtship and mounting behaviour of tortoises is elaborate, and based on a multiple signalling system involving visual, olfactory and acoustic signals. Vocalizations related to mounting seem to be particularly significant because tortoises vocalize mainly at this time. Vocalizations and courtship behaviour may be costly for males, and if these costs increase differentially for different males, then the potential exists for vocalizations and displays to reveal male individual quality. In this correlative study, we analysed relationships between male mounting success and morphological and behavioural traits, particularly acoustic signals, exhibited by male marginated tortoises (Testudo marginata) during courtship, in a group of 94 individuals breeding in semi-natural enclosures. For each male, we estimated general body condition, courtship intensity and mounting success; calls of mounting males were recorded and four sonagraphic features were measured. Calls differed significantly among males, and two features varied according to body condition. Male mounting success significantly increased according to the male/female size-ratio, suggesting the existence of a size-based assortative mating. Mounting success was also highly correlated with courtship intensity, measured as number of bites and rams given to females before mounting, and with number of calls emitted during mounting. Finally, mounting success was negatively related to call duration. To our knowledge, this is the first study in which features of tortoise vocalizations are shown to convey reliable information about male quality in socio-sexual contexts.Communicated by T. Czeschlik 相似文献
16.
We studied two courtship displays of male peafowl (Pavo cristatus), focusing particularly on male orientation relative to the position of the sun. During the “wing-shaking” display, females
were generally behind the displaying male, and male orientation with respect to the position of the sun was not significantly
different from random. However, during the pre-copulatory “train-rattling” display, males were on average directed at about
45° to the right of the sun azimuth with the female positioned directly in front, suggesting that this behaviour is involved
in the communication of a visual signal. A model presentation experiment confirmed that courting peacocks were more likely
to perform the train-rattling display when the female was on the sunny side of their erect train, but more likely to perform
wing-shaking behaviour when the female was on the shaded side of the male. This study underscores the importance of visual
signalling in peafowl courtship, and we suggest that an angle of about 45° relative to the sun may allow males to enhance
the appearance of their iridescent eyespot feathers.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
17.
Despite widespread recognition that intersexual interactions shape reproductive strategies, studies of male competition do
not typically include effects imposed by females. In cannibalistic redback spiders, escalated fighting between rival suitors
is predicted, as males are unlikely to mate with more than one female, and strong first-male sperm precedence favours mating
with virgins. In staged competitions for matings between size mismatched rivals, smaller males adopted an alternative sneaking
strategy. However, despite initial agonistic interactions, larger males did not pursue or incapacitate smaller males. When
inter-male competition occurred, females struck at males frequently, although strikes were rarely seen when males courted
in the absence of a rival. After minimal fighting, larger males engaged in significant courtship (3 h) rather than killing
inferior rivals. Prolonged courtship was favoured by female behaviour, as males that attempted rapid copulation (smaller,
sneaking males) were cannibalised before mating was completed. This premature cannibalism significantly decreases paternity
in redback spiders. Thus, significant features of male competitive behaviour (i.e. prolonged courtship by larger males) may
be predicted with consideration of the female’s response to male reproductive strategies. Although the effect of females may
be more subtle in systems without the extreme reversed size-dimorphism of redbacks, these results suggest that female interests
should be explicitly considered when studying inter-male interactions. 相似文献
18.
To respond appropriately to communication signals, animals must have the ability to decipher signal meaning. At a basic level,
interpreting the difference between territorial and courtship signals can be vital for the survival and reproduction of social
animals. Male and female fiddler crabs communicate with claw-waving displays, but the function of these waves remains uncertain.
Species differ in the context in which they wave: Some wave during courtship, some during territorial defence and some during
both. In this paper, we provide evidence that males of an Australian species of fiddler crab, Uca perplexa, use two different types of claw waving display, lateral and vertical. Lateral waves are employed solely in a courtship context,
whilst vertical waves are employed during courtship as well as territorial interactions. Using video recordings, we show that
lateral waves were produced spontaneously (broadcast), and their frequency increased only in the presence of female wanderers.
Vertical waves were not broadcast but were elicited by male wanderers during agonistic interactions and female wanderers during
close range courtship. Male resident U. perplexa were able to discriminate the sex of wandering crabs on the mudflat at distances of 32 cm. During all resident–wanderer interactions,
residents attempted to maintain a position directly between the wanderer and the home burrow and orient themselves to face
females and to present the major claw towards males. To our knowledge, this is the first demonstration of the multiple use
of waving displays in a fiddler crab species. 相似文献
19.
Semilunar or lunar reproductive rhythms that follow tidal cycles are common in marine animals. For brachyuran crabs, an adaptive explanation for the synchronous release of larvae in phase with the tidal cycle is that females release larvae when their offspring are best able to escape predators. As a corollary to this hypothesis, the synchronous male reproductive cycle is selected to be in phase with female receptivity. As an alternative hypothesis, we propose that variation in food abundance influences the onset and intensity of the semilunar courtship cycle. We tested this hypothesis in male fiddler crabs ( Uca lactea) by experimentally manipulating food availability for 4 weeks. Food-supplemented males built more semidomes and waved for more days than did food-deprived males or untreated control males. Moreover, food-supplemented males began courtship earlier and the median courtship day advanced with an increase in food. Courtship intensity was not related to crab size. These results provide the first evidence in marine animals that changes in food abundance due to the tides, and hence in phase with the semilunar cycle, influence male reproductive rhythm. 相似文献
20.
Doris Preininger Markus Boeckle Anita Freudmann Iris Starnberger Marc Sztatecsny Walter Hödl 《Behavioral ecology and sociobiology》2013,67(9):1449-1456
Many animals use multimodal (both visual and acoustic) components in courtship signals. The acoustic communication of anuran amphibians can be masked by the presence of environmental background noise, and multimodal displays may enhance receiver detection in complex acoustic environments. In the present study, we measured sound pressure levels of concurrently calling males of the Small Torrent Frog (Micrixalus saxicola) and used acoustic playbacks and an inflatable balloon mimicking a vocal sac to investigate male responses to controlled unimodal (acoustic) and multimodal (acoustic and visual) dynamic stimuli in the frogs’ natural habitat. Our results suggest that abiotic noise of the stream does not constrain signal detection, but males are faced with acoustic interference and masking from conspecific chorus noise. Multimodal stimuli elicited greater response from males and triggered significantly more visual signal responses than unimodal stimuli. We suggest that the vocal sac acts as a visual cue and improves detection and discrimination of acoustic signals by making them more salient to receivers amidst complex biotic background noise. 相似文献