The presence of neighbors affects waving display frequency by Scopimera globosa (Decapoda, Ocypodidae)

Scopimera globosa, a small ocypodid crab, rhythmically raises and lowers its body and both chelae in a waving display when it is not interacting directly with another individual. To determine whether waving is a social signal and to deduce its possible function, we manipulated the sex and density of crabs in a field enclosure and recorded the waving frequency of males. Males with abundant female neighbors waved significantly more often than when the same males were caged with abundant male neighbors. Males caged with fewer neighbors of either sex seldom waved. Thus, males waved most in the presence of females, especially at high density, and least in the presence of other males, suggesting that waving may function in female acquisition. Received: August 18, 1998 / Accepted: October 2, 1999     

Microhabitat selection and audible sexual signalling in the wolf spider Hygrolycosa rubrofasciata (Araneae, Lycosidae)

We studied the microhabitat selection and male sexual signalling behaviour in the wolf spider Hygrolycosa rubrofasciata (Ohlert). Males strike dry leaves with their abdomen, producing an audible sexual drumming signal, and females use this signal to choose mating partners. In the field we followed male drumming rate and microhabitat selection using both the mark–recapture method and direct observations. In the laboratory we conducted an experiment on male microhabitat and drumming substrate selection. We found that in the field males were not distributed randomly among the habitat; fewer males were found in areas that had high sedge cover, low elevation, and low dry leaf cover. In the laboratory experiment, males spent more time on dry leaf substrate. Drumming rate in the field was positively correlated with dry leaf cover and in the laboratory males clearly preferred dry leaves as drumming substrate. Temperature was positively correlated with male drumming rate, and with male and female mobility. We conclude that in H. rubrofasciata male distribution and sexual signalling rate, and thus mating success, are greatly affected by environmental factors. Therefore, males may be sexually selected to make effective use of their signalling habitat by active microhabitat choice. Received: 27 December 1999 / Received in revised form: 14 February 2000 / Accepted: 14 February 2000     

Honesty of agonistic signalling and effects of size and motivation asymmetry in contests

Game theoretical models predict that the main function of fighting behaviour is to assess the relative fighting ability of opponents. The sequential assessment game has often been used to investigate contests, while honest signalling theory has received much less attention. With the wolf spider Hygrolycosa rubrofasciata we investigated whether male agonistic signalling can reveal honest information about fighting ability, and how size and motivation asymmetries affect male fighting behaviour. We also determined whether male–male competition affects the courtship behaviour of the males. We found that agonistic drumming activity is an honest indicator of male fighting ability, and that relative size asymmetry and motivation to fight both contribute to the fighting ability. We also found that male–male competition decreases the courtship drumming rate of subdominant males, suggesting that male–male competition limits the opportunities for female choice. We conclude that sequential assessment and honest signalling may both be used in settling contests, and that they may be used simultaneously. Received: 10 December 1998 / Received in revised form: 23 June 1999 / Accepted: 5 July 1999     

Waving Display in Females of Uca polita and of other Australian Fiddler Crabs

Since 1979 it is known that, in Australian species of Uca, female waving exists in addition to usual male display. The present paper deals mainly with female waving in U. polita studied in Darwin (North Australia). A few remarks on U. dampieri, U. vomeris, U. seismella and U. hirsutimanus are added. The species mentioned are members of two species groups or subgenera, which characterizes female waving as an ancestral (plesiomorph) trait. Frame by frame analysis of film sequences (open air shots) indicate homology of movements in the two sexes of U. polita. As in males, waving of females can be combined with locomotion on radial paths starting from the burrow entrance and the display is performed in series with a corresponding number of gestures. Unlike males, waving females mostly use both their chelipeds and tend to show shorter durations with regard to many of the waving parameters chosen. However, significant differences refer only to a limited number of parameters. The biological context of female waving was gathered from films and field observations. High intensity waving is released by conspecifics approaching from far (wanderers without burrows) and from the neighbourhood. Typically, only females and small males elicit high intensity display in a resident female. Waving normally stops in presence of larger males, especially of the male living in a resident breeding unit with the female in question. In spite of this, a pure agonistic (defensive) character of female waving is unlikely. Advertising of breeding condition seems to play a role similar to that in males. The few displaying females that exist in a given colony (about 2.5% in U. polita) show signs of special sexual excitement: brightening of carapace colours and sometimes spontaneous performance of waving, i.e. display immediately after emergence from the burrow in absence of any conspecific.     

SEXUAL SELECTION IN A WOLF SPIDER: MALE DRUMMING ACTIVITY,BODY SIZE,AND VIABILITY

Females are often believed to actively choose highly ornamented males (males with extravagant morphological signals or intense sexual display), and ornaments should be honest signals of male viability. However, this belief is relying only on some pieces of empirical evidence from birds. Our study reports active female choice on sexual display that indicates male viability in spiders. We established trials in which we studied female choice in relation to male courtship drumming activity and body size. Females chose the most actively drumming males as mating partners, but the body size of the males did not seem to be selected. Male drumming activity turned out to be a good predictor of male viability, whereas male viability was independent of male body mass. Our results suggest that by actively choosing mates according to male drumming performance, but independently of male body mass, females are preferring viable males as mates. Because Hygrolycosa rubrofasciata males do not provide obvious direct benefits to their offspring, females may gain some indirect benefits; offspring may have higher chance of survival, or the offspring may inherit the attractiveness of their father.     

Olfactory conditioning in mate searching by the parasitoid Aphidius ervi (Hymenoptera: Braconidae)

Despite the fact that insect learning capacity has been broadly demonstrated, the role that this process plays during mate searching has been scarcely explored. We studied whether the sexual behaviour of a male parasitic wasp can be conditioned to the odours from two alternative host plant complexes (HPCs) present during its first copulation. The experimental subjects were newly emerged males of the aphid parasitoid, Aphidius ervi, and two alternative HPCs (alfalfa or wheat). In the training protocol, copulation experience corresponded to an unconditioning stimulus and HPC odours to the conditioning stimuli. The initial (just after eclosion) and trained responses were assessed in a glass Y-olfactometer. The results showed that neither alfalfa HPC nor wheat HPC stimuli elicited sexual-related behaviours in initial male responses. Conversely, both HPCs triggered strong attraction and wing fanning courtship behaviour in trained responses when the male was exposed to a female plus HPC during training. In males trained with females plus a given HPC but tested with the alternative HPC in the olfactometer, trained response showed a similar trend to the non-associative treatments. Hence, through learning, the olfactory stimulus context present during copulation could become a predictive cue for further mate searching. These results are discussed in terms of parasitic wasp ecology and host fidelity.     

Behavioural responses of male ruffed grouse (Bonasa umbellus,L.) to playbacks of drumming displays

Birds use a variety of sounds in their courtship displays, but the majority of behavioural studies have focused on vocalizations. In contrast, little is known about how non‐vocal sounds, or sonations, are used, even though many avian species produce them. The ruffed grouse (Bonasa umbellus) is a useful species to examine non‐vocal sounds because they lack vocal components in their courtship and rely on a non‐vocal sound to attract mates and defend their territory. Their courtship display, known as “drumming,” is created by the wings, and the number of pulses and speed (pulse rate) varies significantly among males. Anecdotal evidence suggested that males can affect the drumming behaviour of neighbouring males in drumming “duels” in an analogous way to song contests. Here, we test whether males do respond to the playback of drumming sounds of an unfamiliar male. Using a portable speaker system, we played recordings of drumming displays to males that were actively drumming themselves. Throughout each playback, we recorded the drumming behaviour of target males so that we could assess whether drumming activity changes following a playback as well as whether males change the speed of their display. Overall, male grouse were equally likely to approach the speaker or continue drumming following a playback. For those males that continued drumming, their drumming pulse rate was significantly faster following playbacks, but they drummed less often. These results indicate that male ruffed grouse do respond to drumming sounds, but the specific response differs among males. Because the differential response was not related to colour phase or whether a male was drumming in proximity to other males, we suggest that the response of individuals likely varies with other traits, such as hormone levels or behavioural syndrome.     

Spatial and behavioural measures of social discrimination by captive male zebra finches: Implications of sexual and species differences for recognition research

All bird species reproduce sexually and individuals need to correctly identify conspecifics for successful breeding. Captive zebra finches are a model system for studying the factors involved in species recognition and mate choice. However, male zebra finches’ behavioural responses in a spatial preference paradigm to a range of estrildid finch species, other than domesticated Bengalese finches, remain unknown. We investigated spatial and display responses of male zebra finch subjects to stimulus females between conspecific and four phylogeographically relevant finch species, in addition to female Bengalese finches. Surprisingly, male subjects did not show consistent spatial association with conspecific over heterospecific females. Overall, as predicted by sexual selection theory, the spatial proximity responses of males were less discriminatory compared to female zebra finches’ responses tested previously using the same paradigm. However, male subjects showed consistently more behavioural displays towards female conspecifics than heterospecifics which were positively related to the behavioural display rates of the respective female stimuli. Some male behavioural responses, other than song, also showed significant differences between the different stimulus species and consistently differed across individual test subjects, with the most individual subject variation seen in choice trials between female conspecific and Bengalese finch stimuli. The results are important for the design and interpretation of future behavioural and neurobiological experiments on species recognition systems using the zebra finch as a model species.     

Courtship behavior of the mosquitoSabethes cyaneus (Diptera: Culicidae)

Unlike any other mosquito reported, Sabethes cyaneus(Fabricius) displays an elaborate courtship before and during copulation. A male approaches a female suspended from a horizontal stick, suspends himself in front of her as he grasps her folded wings, and proceeds with a series of discrete stereotyped behaviors that involve proboscis vibration and movement of iridescent blue paddles on his midlegs. The sequence of these behaviors is as follows: freeleg waving, swinging, copulation attempt, superficial coupling, waving, genital shift, waggling, and release. Insemination occurs after genital shift. The only overt reciprocation by the female is abdomen lowering during the male's swinging. Courtship is often unsuccessful, and males are usually rejected during freeleg waving. The relation between male performance and mating success remains obscure.     

Are females of Ilyoplax pusilla (Brachyura: Dotillidae) attracted to groups having more waving males?

Males of the dotillid crab Ilyoplax pusilla wave at approaching females during the breeding season. They also, however, often perform waving that is not directed toward any particular individual. This undirected waving is associated with the presence of male neighbors and may function in male–male competition. It may also, however, act as a long-range female attractant. To test whether undirected waving functions to attract females, we conducted a field experiment that manipulated the abundance of waving males. We found that females preferred to approach groups that had more waving males. This suggests that undirected waving by male I. pusilla functions as a long-range courtship signal.     

Courtship tactics by male Ilyoplax pusilla (Brachyura, Dotillidae)

Mating in the dotillid crab Ilyoplax pusilla occurs after the female enters the male’s burrow in the tidal flat. Males use two tactics to cause females to enter their burrows for mating: the male either directs claw waving to the female (courting-wave display), to which the females responds by following the male to his burrow, or the male runs rapidly away from, then back toward, his burrow (dash-out-back display), which startles the female into his burrow. Males more often used the courting-wave than the dash-out-back display, but mating success did not differ between the two tactics. Male use of either tactic was influenced by date, female density and male size; the courting-wave display was used by larger males, later in the breeding period, and under higher female density.     

Coordination and neuromuscular control of rhythmic behaviors in the blue crab,Callinectes sapidus

The stereotypical courtship display (CD) behavior of the male blue crab, Callinectes sapidus, includes an unusual component: the rhythmic waving of the swimming appendages above the carapace. This behavior occurs in a unique context but it resembles two other rhythmic behaviors performed using the swimming legs: sideways swimming and backward swimming. As a first step to understanding the mechanisms that allow the expression of apparently different rhythmic motor patterns, we have examined these behaviors using slow motion video analysis and electromyography of the basal muscles of the swimming legs in freely behaving crabs. The results show that these behaviors are distinguished by four parameters: the frequency of leg waving, the phase relationship between the legs, the presence of a stationary pause in basal muscle activity combined with rotation of the distal leg during CD, and an extended range of motion of these legs during CD and backward swimming, relative to sideways swimming. EMG analysis revealed that during sideways swimming, the sequence of muscular activity between the two legs was different. In contrast, during CD and backward swimming the sequence of activity for these legs is identical.Abbreviations CD courtship display - EMGs electromyograms - CD AMP courtship display in crabs with amputated fifth legs - CD1 crabs that voluntarily used one leg to perform courtship display waving - CD 1–3 courtship waving in cycles 1–3 - CD MID courtship waving after cycles 1–3 - M-C meral-carpal joint     

Calling Patterns in Male Responses to Conspecific Playbacks in the Johnstone's Whistling Frog Eleutherodactylus johnstonei

Vocal interactions are common in chorusing frogs. Changes in the calling patterns of Eleutherodactylus johnstonei males were analyzed by recording their responses to playbacks of conspecific calls repeated at fixed periods (long: 1.7 s, short: 0.98 s). The call period and timing, estimated through the onset response time, were determined for each male. Males reduced and regularized the period of their calls in response to both stimuli, regardless of their absolute and relative period (i.e., the difference between the male's period and the stimulus period). Males avoided initiating their calls during ongoing stimuli, but did not time their calls in the silent gap between successive stimuli in ways that reduced the probability of overlap: the proportion of calls without overlap did not depart from random expectations when the silent gap was long, and was smaller than expected when the gap was short. This result indicated that males react to the presence of the virtual competitor but not to its particular characteristics. Fixed responses have been described in other anurans, and often relate to trade-offs between female attraction, male competition, predator attraction, and depletion of energy reserves. Lack of coordination with the stimuli, beyond inhibition of calling during an ongoing stimulus, also indicates somewhat rigid vocal strategies, at least under the experimental conditions. Results from the short period trials suggested a compromise between maintaining a call period and avoiding call overlap. Whether female behavior is influenced by call interference and whether males pay selective attention to distant males instead of to close neighbors must be investigated to better understand the vocal behavior of E. johnstonei .     

A translocation experiment explains regional differences in the waving display of the intertidal brachyuran crab Ilyoplax pusilla

Male waving display by the dotillid crab Ilyoplax pusilla differs among local populations in the frequency of full cheliped extension. In order to clarify whether the local variation is caused by behavioral characteristics specific to a local population or by differing environmental conditions, reciprocal translocation experiments were carried out between two populations in which male waving display clearly differs. The translocated crabs continued to wave in their new environment as they did in their source population, and control crabs exhibited no change in waving. This result suggests that local differences in the claw-waving display of male I. pusilla are caused by intrinsic population differences.     

Vision-based ability of an ant-mimicking jumping spider to discriminate between models,conspecific individuals and prey

Myrmarachne assimilis, an ant-like (myrmecomorphic) jumping spider (Araneae, Salticidae) from the Philippines, is a Batesian mimic of Oecophylla smaragdina, the Asian weaver ant. Salticids are well known for their acute eyesight and the elaborate vision-based display behaviour they adopt during encounters with conspecific individuals, but most salticids are not myrmecomorphic. Despite its unusual morphology, M. assimilis adopts display behaviour during intraspecific interactions that is similar to the display behaviour of more typical salticids. The specificity with which M. assimilis deploys display behaviour is investigated and provides insights into this mimic’s ability to differentiate, by sight alone, between models, conspecific individuals and prey. During each standardized test, an adult M. assimilis female was in a large cage along with a small transparent glass vial, a stimulus animal being enclosed in the vial such that potential optical cues, but not potential chemical cues, were available to the tested M. assimilis individual. Depending on the test, the stimulus animal was another adult M. assimilis female, a house fly (prey) or an ant (Camponotus sp. or O. smaragdina). Only the conspecific female consistently elicited display from M. assimilis, implying that M. assimilis is a Batesian mimic that can, when relying on vision alone, discriminate between conspecific individuals, models and prey. Received 12 June 2006; revised 22 September 2006; accepted 26 September 2006.     

Reactions to Potential Predators in Captive-Born Marmosets (Callithrix penicillata)

We describe the behavioral repertoire of captive-born black tufted-eared marmosets (Callithrix penicillata) elicited by brief exposures to three potential mounted taxidermized predators (caracara hawk, Polyborus plancus; rattlesnake, Crotalus durissus; oncilla, Leopardus tigrina), and a stuffed toy. For each of the four stimuli, we submitted the subjects to a 9-min trial divided into three consecutive intervals: a 4-min pre-exposure baseline observation, a 1-min stimulus exposure, and a 4-min postexposure observation period. We positioned stimuli in front of each subject's home cage, and video-taped trials for behavioral analysis. During exposures to the potential taxidermized predators, we heard tsik-tsik vocalization and alarm behavior. After exposures, only the cat induced these reactions. All stimuli elicited observational reaction, albeit only during exposure intervals. Further comparisons between the three trial intervals indicated a decrease in the time spent in proximity to the cat during exposures, while an increase in proximity occurred when subjects were exposed to either the hawk or snake for the same period. Taken together, the behavioral responses during and after exposures to the taxidermized oncilla suggest that this stimulus is capable of inducing strong and persistent emotional reactions in Callithrix penicillata.     

Signaling without the risk of illegitimate receivers: do predators respond to the acoustic signals of <Emphasis Type="Italic">Cyprinella</Emphasis> (Cyprinidae)?

Acoustic and visual signals are commonly used by fishes for communication. A significant drawback to both types of signals is that both sounds and visual stimuli are easily detected by illegitimate receivers, such as predators. Although predator attraction to visual stimuli has been well-studied in other animals, predator response to acoustic stimuli has received virtually no research attention among fishes and snakes. This study assessed whether the calls of male tricolor shiner (Cyprinella trichroistia) made during the breeding season would attract potential predators. We also examined the effect of visual stimulus of tricolor shiners on predators. Predators used were red eye bass (Micropterus coosae) and midland water snakes (Nerodia sipedon pleuralis). Neither predator was attracted to tricolor sounds when presented alone. Micropterus coosae responded significantly more to a visual stimulus, and to a combination of visual and acoustic stimuli, but with no greater intensity in the latter. Nerodia sipedon pleuralis did not responded to visual stimulus presented alone, but did respond to visual and acoustic stimuli presented simultaneously, and with greater intensity to the latter, indicating that acoustic signals may play a role in prey detection by N. sipedon pleuralis.     

Different Stimuli Reduce Attraction to Pollinators in Male and Female Figs in the Dioecious Fig Ficus hispida

Fig trees ( Ficus ) and their obligate pollinating wasps (Hymenoptera, Chalcidoidea, Agaonidae) are a classic example of a coevolved mutualism. Pollinating wasps are attracted to figs only when figs are receptive. It has been shown that figs will lose their attraction to pollinators sooner in monoecious and male dioecious figs when multiple pollinators have entered the enclosed inflorescence. However, little is known about the nature of the stimulus inducing the loss of attraction. By conducting experiments on the functionally dioecious fig, Ficus hispida , we show that (1) different stimuli induce the loss of attraction in each sex, pollination in female figs, and oviposition in male figs; and (2) foundress number affects the loss of attraction in both sexes only when the prerequisites ( i.e ., pollination in female figs and oviposition in male figs) have been satisfied. In general, the more foundresses that enter, the earlier the fig will lose its receptivity. We argue that the stimuli in male and female figs are adaptations to the fulfillment of its respective reproduction.     

Choosing a mate in a high predation environment: Female preference in the fiddler crab Uca terpsichores

The interplay between a receiver's sensory system and a sender's courtship signals is fundamental to the operation of sexual selection. Male courtship signals that match a female receiver's preexisting perceptual biases can be favored yet the message they communicate is not always clear. Do they simply beacon the male's location or also indicate his quality? We explored this question in a species of fiddler crab Uca terpsichores that courts under elevated predation risk and that mates and breeds underground in the safety of males' burrows. Sexually receptive females leave their own burrows and are thereby exposed to avian predators as they sequentially approach several courting males before they choose one. Males court by waving their single greatly enlarge claw and sometimes by building a sand hood next to their burrow entrance. Hoods are attractive because they elicit a risk‐reducing orientation behavior in females, and it has been suggested that claw waving may also serve primarily to orient the female to the male. If the wave communicates male quality, then females should discriminate mates on the basis of variation in elements of the wave, as has been shown for other fiddler crabs. Alternatively, variation in elements of the claw waving display may have little effect on the display's utility as a beacon of the location of the male and his burrow. We filmed courting males and females under natural conditions as females responded to claw waving and chose mates. Analysis of the fine‐scale courtship elements between the males that females rejected and those they chose revealed no differences. When predation risk during courtship is high, males' courtship displays may serve primarily to guide females to safe mating and breeding sites and not as indicators of male quality apart from their roles as beacons.     

Aversive Responses of Female Mice to the Odors of Parasitized Males: Neuromodulatory Mechanisms and Implications for Mate Choice

The detection and avoidance of parasitized conspecifics is proposed to have important consequences for the behavior of animals, especially as related to mate choice. A reduction in pain sensitivity (i.e. analgesia) is a major correlate of exposure to real or potential danger and threatening stimuli, facilitating the expression of various active (e.g. fleeing) and passive (e.g. immobilization) defense responses. The present study examined pain sensitivity (latency of a foot-lifting response to 50 ° C thermal surface) of female mice, Mus musculus, that were exposed to the urine and other odor secretions of male mice subclinically infected with the naturally occurring, enteric, sporozoan parasite, Eimeria vermiformis. A 30-min exposure to the odors of a parasitized male induced an analgesia in the female mice that was found to be mediated by the increased activity of endogenous opioid peptide systems. A brief 1-min exposure to the male odors induced a shorter duration and lower amplitude analgesia of a non-opioid (serotonergic) nature. Maximum analgesic responses were induced by the odors of pre-infective [5 days post-infection (PI)] and infective (day 10 PI) males, with significantly lower responses elicited by the odors of post-infective (day 17 PI) male mice. Exposure to the odors of unparasitized males had no significant effects on the pain sensitivity of female mice. These results indicate that female mice can distinguish between the odors of parasitized and non-parasitized male mice, and find the odors of parasitized males threatening and/or stressful. These odor-induced analgesic responses and their neurohormonal correlates may be part of an adaptive preparatory defense mechanism that facilitates the detection and avoidance of parasitized males by female mice and contributes to female mate choice.