bluuebunny/crossref_metadata_2025 huggingface dataset:
Directional Preferences in the Autumn Migration of the Red Admiral (Vanessa atalanta)
Authors: Benvenuti Silvano , Dall'Antonia Paolo , IoalÈ Paolo
Published: May 2010

The paper describes the orientation performance of the red admiral in the course of its migratory movements through the Italian peninsula, a region where systematic studies of this butterfly species have not been carried out before. Our results show that red admirals exhibit seasonal bidirectional migratory movements between breeding and wintering grounds. Orientation performances, directional preferences in the autumn and spring were recorded and discussed; in addition, we have documented a progressive eastward shift of the main flight direction, during the autumn migratory season, which appears to be related to air temperature. Speculative explanations for this shift of flight direction, which has never been recorded before, are given.
Sound‐pressure Levels and Song Preferences in Female Red‐winged Blackbirds (Agelaius phoeniceus) (Aves, Emberizidae)
Authors: Searcy William A.
Published: May 2010

Female red‐winged blackbirds (Agelaius phoeniceus) were tested for response to songs of male red‐winged blackbirds differing in sound‐pressure level (SPL) of playback. Subjects gave significantly more copulation‐solicitation displays in response to playback of songs at 85 dB SPL than to playback of the same songs at 72 dB SPL. The strength of the preference, as judged by the ratio of response to high and low SPL playback (1.15:1), was lower than that of preferences for high SPL shown by insects and anurans. Female red‐winged blackbirds responded preferentially to a conspecific song relative to a heterospecific imitation, even when the imitation was presented at an SPL 13 dB higher than that of the conspecific song. By contrast, female redwings did not maintain a preference for multiple conspecific song types over single types when the single song types were presented at the higher SPL. These results are compatible with Klump & Gerhardt's (1987) suggestion that the intensity independence of female preferences varies with the relative benefit females obtain from each preference.
Do the Anemonefish Amphiprion ocellaris (Pisces: Pomacentridae) Imprint Themselves to Their Host Sea Anemone Heteractis magnifica (Anthozoa: Actinidae)?
Authors: Arvedlund Michael , Nielsen Lis Engdahl
Published: May 2010

Juvenile anemonefishes detect their host sea anemone by olfactory stimuli; in order to investigate whether this behaviour is innate or acquired, the anemonefish species Amphiprion ocellaris was bred in two different ways: 1. With no host sea anemone present at all (–A); and 2. With the specific host sea anemone Heteractis magnifica present in the hatching aquarium, so that these eggs were laid and hatched close to the sea anemone, as in nature (+A).

The two different types of juvenile A. ocellaris were presented to the odours of the host sea anemone H. magnifica in two sets of short‐term experiments with the host (a) visually hidden in a net cage, and (b) visible but physically separated from the anemonefishes. In both cases, a water flow was established between fishes and host. The +A‐fishes found their host by olfactory and not by visual stimuli. In both series, the –A‐fishes showed a significantly lower affinity behaviour towards the odour compounds from the host sea anemone than the +A‐fishes did.

A third type of experiment was a direct confrontation between fishes and host; here, the –A‐fishes were indifferent towards the host sea anemone for almost 48 h, while the +A‐fishes acclimated to the host sea anemone within the first 5 min of the direct confrontation.

The results of this study suggest that Amphiprion ocellaris imprints itself olfactorily to its species‐specific host sea anemone Heteractis magnifica, and, furthermore, may be genetically disposed towards olfactory recognition of the host sea anemone.
Ineffective Maternal Care of a Subsocial Bug against a Nymphal Parasitoid: a Possible Consequence of Specialization to Predators
Authors: Kudo Shin‐ichi
Published: May 2010

In the subsocial bug Elasmucha putoni, females lay egg masses on leaves of fruit‐bearing wild mulberry trees. Parent females invariably remained straddling their offspring until the offspring moulted to the second instar on natal leaves. Thereafter, the females usually settled on the stem of shoots which harboured second‐or‐later‐instar nymphs feeding on fruit or aggregating on leaves, and faced toward the base of the shoot. To evaluate the effectiveness of maternal attendance on parasitism of nymphs by a braconid wasp, I divided the boughs of each mulberry tree into two experimental groups: a single bough which was isolated from the others by Tanglefoot treatments and on which guarding females were removed from broods before the second instar, and other boughs on which broods were left intact as controls. The experiments showed that nymphal parasitism was not affected by the presence of females. The position and orientation of females attending second‐or‐later‐instar nymphs is probably effective for detecting predators approaching the nymphs by walking along the stem; however, this posture may prevent the females from detecting parasitoids, which fly and land directly on plant parts close to the nymphs. The ineffectiveness of the females in providing defence against the parasitoid is possibly associated with a specialization of the attending posture to pedestrian predators: a parental defensive behaviour specific to these predators may make the offspring more vulnerable to the parasitoid.
Development of Tonal Quality in Birdsong: Further Evidence from Song Sparrows
Authors: Peters Susan , Nowicki Stephen
Published: May 2010

Song sparrow (Melospiza melodia) songs are composed largely of pure‐tone notes. Song sparrows raised in acoustic isolation (i.e. never hearing conspecific songs) tend to produce half of their notes with harmonic overtones, an atypical tonal structure, suggesting that exposure to pure tones is necessary for the development of normal tonal quality. The experiment presented here directly investigated the influence of early exposure to songs with different tonal qualities on subsequent production. Seven young song sparrow males were exposed to 16 normal, pure‐tone song sparrow songs and 6 males were exposed to the same 16 song types with added harmonic overtones. Birds in both groups learned equally well, confirming an earlier finding that tonal quality does not influence selection of models during the sensitive period for song acquisition. Birds exposed exclusively to harmonic song models, however, produced over 85% of their learned notes in a pure‐tone fashion, even though they had never heard pure‐tone sounds. Thus, pure tones do not need to be experienced directly by song sparrows, but exposure to some features of species‐typical song models appears to facilitate the reproduction of models in a pure‐tone fashion.
Age‐related Differences in Playfighting Strategies of Captive Male Red‐necked Wallabies (Macropus rufogriseus banksianus)
Authors: Watson Duncan M. , Croft David B.
Published: May 2010

Age‐related differences in the playfighting strategy of captive male red‐necked wallabies Macropus rufogriseus banksianus was examined. Our purpose was to determine whether wallabies adjusted their play in response to their partner's age and, if so, how. The way in which a wallaby played was dependent on the relative age of its partner, and this pattern tended to be the same regardless of whether it was the initiator or reactor of the interaction. If a wallaby's partner was younger than itself it adopted a defensive strategy in which it self‐handicapped by standing flat‐footed, Pawing rather than Sparring, and by not using its full strength. Its greater rate of Shaking suggests that this act may function as an appeasement signal in play. Furthermore, it was highly tolerant of the tactics used by its younger partner and took the more active role in prolonging interactions. If, on the other hand, its partner was older than itself, it adopted an offensive strategy involving vigorous Sparring, increased time in the High‐stance posture and a greater percentage of bouts that were of high intensity. Indeed, it played with even more vigour than when it playfought with wallabies of the same age as itself. Differences in the play of same‐aged partners were in the non‐fighting components of play, while those of differently‐aged partners were in the fighting components. Play between same‐aged partners, however, tended to be more stable and more competitive than that between partners of differing age. These results are discussed with emphasis on the compromises made in order for play to occur and the potential benefits to each partner of play in mixed‐age class encounters. We briefly consider the implications of self‐handicapping in the categorization of macropodid fights as play or aggression.
Signalling Asymmetry in the Communication of the Water Strider Aquarius remigis in the Context of Dominance and Spacing in the Non‐mating Season
Authors: Jabloński Piotr G. , Wilcox R. Stimson
Published: May 2010

The role of high‐frequency ripple signals (HF signals) made by males of the water strider Aquarius remigis was studied in the contexts of competition for food and general spacing behaviour during the non‐mating season. HF signals were played back through the ripple‐producing legs of males during dyadic agonisdc encounters, using a signal‐driven wire coil to oscillate a magnet glued to a leg. These signals were in addition to normal signals. The additional signals significantly increased the number of retreats by non‐magneted males, showing that the signals increased the dominance of a non‐territorial male. Hence, our results increase the number of contexts in which HF signals of A. remigis function. Males, but not females, avoided a site occupied by a magneted dead male through which HF signals were played. Thus, the communication system used by A. remigis males during competition for food seemed to be ignored by females, suggesting sex‐specific signals even in a non‐mating context. Evolutionary models of signalling often assume that contestants have evolved the same repertoire of signals in order to resolve conflicts peacefully. This water strider system thus poses an interesting challenge for future theoretical and empirical research on communication asymmetry.
Song Degradation during Propagation: Importance of Song Post for the Wren Troglodytes troglodytes
Authors: Mathevon Nicolas , Aubin Thierry , Dabelsteen Torben
Published: May 2010

The degradation of bird sounds during long‐range propagation depends on different parameters such as density of vegetation, height from the ground and atmospheric perturbations. We investigated whether the wren Troglodytes troglodytes, a bird species which has a high‐pitched song that is very susceptible to degradation and lives in an environment that is very restricting for sound propagation, has any advantage in choosing relatively high song posts. Song degradation was investigated by analysing sound attenuation, duration of notes and silences, spectrum composition, modifications of frequency‐modulated notes and amplitude fluctuations.

Our data show that the choice of an elevated song post improves the reliability of all song parameters and increases the propagation distance of the song. It also improves the male wren's ability to hear opponent songs. The results are discussed from an ecological point of view.
Pigeon Homing in the Meteorological and Solar‐geomagnetic Environment: what Pigeon Race Data say
Authors: Dornfeldt Klaus
Published: May 2010

In this statistical analysis, the fastest 25% of homing speeds in 5955 races conducted in West Germany on 194 days in 1973–1990 and the return rates in 18 pigeon races held in 1932–1957 in Italy were examined with respect to distance, cloud cover, wind, sferics, solar and magnetic variables. 1. Under sun, the speeds rapidly increased with distance from 120 up to 240 km and slowly declined beyond 240 km. 2. Correlations between race and wind speeds were maximized by rotating clockwise and extrapolating the local surface wind linearly according to the average wind profile (difference between the mean surface and mean 900 m‐height wind vector). The best predictors indicated the speeds of the winds the birds encountered aloft, which were blowing at lower heights in headwinds than in tailwinds. 3. The air speeds correlated negatively with the effective wind forces roughly in agreement with Pennycuick's theory of bird flight. 4. Rates of atmospherics (2.8–38 kHz, 0.02–0.4V/m recorded in Berlin) correlated negatively with the speeds. 5. Under sun, the difference between the fastest and slowest speed correlated with sunspot numbers (R) in a very active solar cycle (1979–1987), but not in the preceding and following cycles which had lesser activity. 6. Under sun, the speeds correlated directly or indirectly with solar and magnetic activity (25% and 21 % of the samples per year and per homeward direction, respectively), but did so only in 9.9% and 6.9% of samples (respectively) when races to the same home area were sampled over the years. Under overcast, most of the correlations were negative. 7. While magnetic disturbances appeared to coincide with higher speeds inconsistently under sun, they appeared to interfere with the speeds consistently under overcast. Under sun, the seasonal median speeds, unlike the daily median ones, correlated negatively with magnetic activity. 8. Hourly variations of the geomagnetic field components correlated negatively with the speeds in 1973–1975 in western, but positively in eastern and southern, homeward directions. 9. The return rates in Italian pigeon races were best predicted by hourly variations of the horizontal intensity of the regional geomagnetic field and second‐best by sunspot numbers. 10. The significance of the results for understanding the role of the meteorological and solar‐magnetic environment in pigeon homing is discussed.
Interspecific Responses of Ringtailed Lemurs to Playback of Antipredator Alarm Calls Given by Verreaux's Sifakas
Authors: Oda Ryo , Masataka Nobuo
Published: May 2010

The ringtailed lemur, Lemur catta, and Verreaux's sifaka, Propithecus verreauxi verreauxi, are diurnal prosimians living sympatrically in Madagascar. Species‐specific alarm calls emitted by each of these two species in response to aerial and terrestrial predators differ acoustically. Behavioural responses of ringtailed lemurs evoked by playbacks of conspecific alarm calls differ when the vocalizations were produced in response to aerial predators as opposed to terrestrial predators. We conducted playback experiments on two populations of ringtailed lemurs, using two types of sifaka alarm calls. One population consisted of free‐ranging groups which lived sympatrically with sifakas, the other was a colony group which had no contact with sifakas. The results illustrate that the former group of lemurs can perceive what type of predators the sifaka calls refer to, whereas the latter group was not able to recognize the difference in the calls.
Chemosensory Recognition of Familiar and Unfamiliar Conspecifics by the Scincid Lizard Eumeces laticeps
Authors: Cooper William E.
Published: May 2010

The ability of broad‐headed skinks (Eumeces laticeps) to distinguish familiar from unfamiliar individuals of the opposite sex and themselves from other individuals of the same sex using only chemical stimuli was examined experimentally. Cloacal chemical stimuli were presented to lizards on moistened cotton swabs and numbers of tongue‐flicks performed in 60 s were recorded. Males emitted significantly greater numbers of tongue‐flicks in response to chemical cues from unfamiliar females than of female cagemates. Response rates of males housed with females and males housed alone to chemical stimuli from unfamiliar females did not differ. Chemical stimuli from unfamiliar males elicited significantly more tongue flicks from males than their own or deionized water, but their own stimuli elicited no more than the odourless control. Females tongue‐flicked significantly more in response to cloacal chemical stimuli from unfamiliar males than from male cagemates. The findings indicate that both sexes of broad‐headed skinks can discriminate between chemical stimuli of familiar and unfamiliar individuals of the opposite sex and that males can distinguish their own cloacal chemicals from those of unfamiliar males. The possible functions of these chemosensory capacities, including location of mates by scent‐trailing and assessment of the presence of sexual competitors, are discussed in relation to the social behaviour of E. laticeps.
Why Do Female Birds Reject Copulations from their Mates?
Authors: Wagner Richard H.
Published: May 2010

Female birds frequently reject copulations from their mates, suggesting a conflict between the sexes. This study analyses behavioural data of socially monogamous razorbills, Alca torda, to examine whether females rejected their mates because of conflicts over fertilization or the pair bond. Among pairs, females rejected 9–70 % of their mates’ copulation attempts and prevented their mates from completing 42–100 % of successful copulations. Copulations terminated by females were half the duration of those terminated by males, and females terminated fewer first copulations than subsequent ones on the same day. These findings indicate that females were motivated to copulate less frequently and for shorter durations than their mates. The sperm competition hypothesis predicts that females reject their mates to increase the probability of being fertilized by extra‐pair males. This hypothesis was not supported because females rejected extra‐pair males similarly to their mates. The female‐mate‐guarding hypothesis predicts that females guard their pair bond by copulating frequently with their mates, thereby depriving the males of time and energy to copulate with and form bonds with other females. This prediction was consistent with a significant negative correlation between the percentage of copulation attempts that females accepted from their mates, and the number of extra‐pair copulations that their mates attempted. However, this correlation was not caused by a trade‐off of males copulating with their mates instead of attempting extra‐pair copulation because males attempted most extra‐pair copulations on days when their mates were absent. A new hypothesis is proposed, namely, that females reject their mates to test the male's commitment to provide essential parental contributions after egg‐laying. The ‘testing‐of‐the‐bond’ hypothesis is consistent with the findings but requires testing.
A Comparison of Four Vocalizations of the GenusTragopan(Aves, Phasianidae)
Authors: Islam Kamal , Crawford John A.
Published: May 2010

Four calls of the genusTragopanwere described and acoustically analysed. Alarm and wing whir calls were very similar in sound and structure in all five species. By contrast, a comparison of 11 physical parameters of advertisement and clicking calls indicated that species separated into three groups: western and Cabot's each separated into their own group, whereas Blyth's, Temminck's and satyr formed another group. It was hypothesized that the tragopan prototype population had their origin in the eastern Himalayas. Thus, the centrally distributed species of tragopans (satyr, Blyth's and Temminck's) retained characteristics of the ancestral population, whereas the peripheral species (western and Cabot's) underwent vocal modifications. Courtship vocalizations, which are under sexual selection pressure, probably serve as species‐isolating mechanisms in sympatric species.
Undirected Song in Wild Zebra Finch Flocks: Contexts and Effects of Mate Removal
Authors: Dunn A. M. , Zann R. A.
Published: May 2010

Wild zebra finches, Taeniopygia guttata, sing frequently throughout the year but the function of undirected song, the most prevalent type, is unknown. Paired males commonly sang undirected song in feeding flocks where it occurred more frequently in the non‐breeding season than in the breeding season. Song rate varied greatly among males. The context of the singer and the absence of any overt responses from flock members excludes direct aggressive and mate‐attracting functions. Performance of undirected song may have energetic costs and predatory risks. The finding that singers are active individuals with ‘spare time’, that are neither hungry, nor tired, nor sexually motivated, suggests that singers are advertising their ‘quality’ as potential mates and/or participants for extra‐pair copulations. When the female partner in non‐breeding pairs was experimentally removed, the rate of undirected song of the ‘widower’ increased significantly. Males quickly re‐paired. This experiment supports the hypothesis that singing in the flock has a mate‐attracting role.
Maternal Defence of a Leaf Beetle is not Effective against Parasitoids but is against Pedestrian Predators
Authors: Kudo Shin‐ichi , Ishibashi Eiji
Published: May 2010

Females of the subsocial leaf beetle Gonioctena sibirica attend their broods on the willow Salix bakko. Females with broods settle on the underside of the basal part of leaves and face towards the base of the shoots. If other arthropods approach such attendant females, the females show aggressive behaviour against the intruder. The effectiveness of maternal care on offspring survival against pedestrian predators and against a parasitoid wasp was evaluated in field experiments using three groups: broods from which parent females were experimentally removed, those from which females were removed and pedestrian predators were excluded by tanglefoot treatments, and control broods. These experiments showed that maternal care was highly effective against pedestrian predators, but parasitism was not affected by the presence of females. Offspring mortality by predation or by parasitism was not usually dependent on larval densities. Position and orientation of attendant females will be effective for them to detect intruders which approach their larvae by walking along the stem, while it can inhibit the females from detecting parasitoids which fly and land directly on the leaf close to the larvae. The results suggest a trade‐off in the effectiveness of prey defensive behaviour against different enemy species: prey defensive behaviour specific to one type of the enemy may make the prey more vulnerable to the other.
Conflicting Territory Use in Males and Females of a Monogamous Ungulate, the Kirk's Dikdik
Authors: Komers Petr E.
Published: May 2010

In monogamous mammals it is often unclear why males do not defend larger territories to attract more than one female. I investigated the territoriality of the monogamous Kirk's dikdik, Madoqua kirki, a dwarf antelope, in which food resources increase with territory size and some males defend enough resources for more than one female. Yet, all males are paired monogamously. When males were removed from small territories, their female partners spent more time outside of their territories than females in large ones. When females were removed, their male partners almost never left. Pairs in small territories spent more time together than pairs in large ones. Paired males left mostly together with their females, apparently not on their own initiative. Presumably because females in small territories left more often, their males spent more time outside in the female's company than males in large territories. I argue that males in smaller territories can keep better track of their females and that they can effectively reduce their females' time outside. Male intrusion pressure was unrelated to territory size, but it increased in the presence of unguarded females. If large territories decrease the ability to mate guard, and if unguarded females attract competing males, then defending large territories may be uneconomical, even it they could attract more than one female. On the other hand, territories must be large enough to satisfy the requirements of a single female.
Mating Systems and Male Size in Australian Hylaeine Bees (Hymenoptera: Colletidae)
Authors: Alcock John , Houston Terry F.
Published: May 2010

The mating systems of seven previously unstudied members of the colletid bee genus Hylaeus Fabricius and one of Hyleoides Smith are described. Male mating tactics can be categorized as territorial (perched males defend flowers or other sites that attract receptive females) or non‐territorial (patrolling males search for receptive females at flowering plants). The four species in which some territorial males occur are characterized by: 1. grappling fights among males for preferred perches; 2. territorial control by larger males; 3. the possession of prominent spines or other projections on the venter of the abdomen in larger males; and 4. the occurrence of some males that are as large as, or larger than, the largest females of their species (the ‘large‐male phenomenon’). In contrast, the four species that lack territorial males are distinctive in that males: 1. do not engage in grappling contests; 2. lack abdominal weaponry; and 3. are smaller than the largest females of their species. In addition, we searched for the large‐male phenomenon in museum collections of four species of Hylaeus that exhibit male abdominal spines (presumed to be the weapons used by territorial individuals) and two other species that lack these attributes (presumed non‐territorial patrolling species). The results tend to support the sexual‐selection‐for‐fighting‐ability hypothesis, which argues that the evolution of unusually large males is a selective consequence of aggressive male—male competition for access to mates. The limitations of the present data set as a comparative test of this hypothesis are discussed.
Testosterone Induces Sexual Release Quality in the Song of Female Canaries
Authors: Vallet Eric , Kreutzer Michel , Gahr Manfred
Published: May 2010

Abstact

We tested the sexual responsiveness of female canaries, Serinus canaria, to two sets of different types of female conspecific songs versus an adult male conspecific song. Female songs were either spontaneously emitted (‘S‐songs’) or were testosterone‐induced (‘T‐songs’). Copulation‐solicitation displays (CSD) were used as an index of female sexual response. Playbacks were performed several days before and during egg laying, a period of natural sexual responsiveness of the females to song. We demonstrated that the weaker sexual displays of female canaries were recorded to S‐songs, thus suggesting that these types of female songs do not contain fully functional sexual releasers. Three T‐songs elicited high levels of sexual displays, thus demonstrating that testosterone treatment may induce sexual release quality in the female songs. Study of the phonology of these three T‐songs strongly suggested that special song phrases may be good candidates as powerful sexual releasers. To test the sexual value of these female song phrases, we carried out a third experiment, using hybrid songs where each of these special T‐song phrase types was included in a well‐known heterospecific context. Two phrases elicited high levels of sexual responses in females. Essential features of the male full song, such as broadband rapid frequency modulations and high repetition rate, are retrieved in both female song phrases. Taken together, these data demonstrate that testosterone treatment not only induces a male‐like structure in the songs of females, but also induces functionally ‘male‐like’ songs. This result allows features of the vocal control network of testosterone‐treated females to be compared with those of adult males singing full songs, to distinguish neural correlates of testosterone‐dependent full songs. However, because testosterone does not induce functionally male‐like songs in all the females, neuroanatomical structure‐function correlations need detailed behavioural analysis.
Female Choice for Male Morphological Traits in House Sparrows, Passer domesticus
Authors: Kimball Rebecca T.
Published: May 2010

Female mate choice for male morphological traits was examined in captive house sparrows in New Mexico, USA. A study of house sparrows in Denmark indicated that male bib size is important in female choice (Moller 1988, 1989). To examine this issue further, and to compare the selective pressures on male morphological traits between the two populations, bibs of males were manipulated to one of four standard sizes and females were allowed to choose from four males, one of each bib size. The amount of time the female spent with each male was recorded for 40 trials. Males were then ranked in each trial, with a rank of 4 given to the male the female spent the most time with. The ranks a male obtained were then averaged to provide an indication of a male's attractiveness to females. Data from 23 different males indicated that bib size was not correlated with a male's average rank, even when the effects of other traits were controlled statistically. In addition, the size of the original (unaltered) bib was not correlated with male average rank. Bill depth was the only trait significantly correlated with a male's average rank. Differences in the populations studied or the methodologies used may have led to differences between the results obtained in this study and that of Moller (1988).
Differential Kin Discrimination by Red‐spotted Newts (Notophthalmus viridescens) and Smooth Newts (Triturus vulgaris)
Authors: Gabor Caitlin R.
Published: May 2010

In organisms lacking parental care or when eggs of more than one female are layed together, parents preferentially tend to avoid eating their own offspring. In some species of newts (Caudata: Salamandridae), there is no parental care and cannibalism of eggs and larvae occurs when philopatric adults remain in the pond throughout the breeding season where eggs and larvae develop. Kin discrimination by both adult newts and larvae would be expected to occur during the breeding season as it would enable individuals to benefit from the nutrients obtained from eating eggs and larvae while they avoid eating close relatives. The effects of kinship on cannibalism of eggs and larvae were examined in two species of newts. In separate, but similar, paired behavioral trials adult female red‐spotted newts,Notophthalmus viridescens, and smooth newts,Triturus vulgaris, were allowed to consume their own egg or an egg from another female. Female red‐spotted newts, but not smooth newts, preferred to eat eggs of other females rather than their own, and overall smooth newts were ‘reluctant’ to eat conspecific eggs. To test for ontogenetic shifts in discrimination abilities, additional experiments were performed with adult female red‐spotted newts paired with their own larvae and a larva from another female. In addition, the effects of kinship on the attraction or repulsion of larvae was also studied in red‐spotted newts. Females showed no significant discrimination abilities during acts of cannibalism on larvae. Larvae spent similar amounts of time with siblings and non‐siblings. These results suggest that the ability of adult newts to discriminate among eggs varies between species and that the elicitation of a kin‐discrimination response may be context‐dependent. For red‐spotted newts, there was no evidence of discrimination abilities within and between other life‐history stages.
Sexual Interference in the Sword‐tailed Newt, Cynops ensicauda popei (Amphibia: Salamandridae)
Authors: Sparreboom Max
Published: May 2010

This paper describes competitive interaction between males of the salamandrid Cynops ensicauda popei. The sexual behaviour of the male is influenced by the presence of a second, rival, male. Competition for access to the female and other male interactions continuously interrupt ongoing courtships. Spermatophore pick‐up success is lower than in encounters involving single pairs. During triad encounters, fewer spermatophores were deposited than in dyad encounters, due to interference during the creep stage of courtship.

Two basic forms of male sexual interference were distinguished: ‘lure away’ during the creeping stage, from a position that is different from the direction of creep; and ‘female mimicry’, during which the male presses his snout alternately against the courting male's tail and the female's snout. In both forms, a rival male may shove one of the courting individuals away.

The repertoire of sexual behaviour patterns of Cynops ensicauda popei appears to be less complex and varied than that of most Triturus species. The courtship of Cynops places less emphasis on display behaviour with tail and body, and a stronger emphasis on the creeping stage, where the male carefully leads the responsive female over a series of spermatophores, but during which rival males may interfere in a variety of ways.
Vocal Signalling of the Great Crested Flycatcher, Myiarchus crinitus (Aves, Tyrannidae)
Authors: Smith W. John , Smith Anne Marie
Published: May 2010

The singing and related vocalizing of great crested flycatchers, Myiarchus crinitus (Aves, Tyrannidae), included at least 12 different vocalizations. Each vocalization correlated with (and thus made information available about) a distinctive range of behaviour, from unassertive to more actively responsive, provocative or even confrontational. Four were used by individuals primarily when alone and not initiating close social encounters. The eight other vocalizations were uttered primarily in close encounters: one in preliminaries to such events, two predominantly in encounters with opponents, another in close associating of mates, two in duetting, and two infrequently, mostly in confrontations. The division of the repertoire into sets of vocalizations providing information about either low or elevated probabilities that a signaller will undertake the behavioural initiatives that precede, shape or sustain social interactions parallels a division found in other recently studied passerines. Such information is pertinent to individuals' decisions to forego or start close interactions with, for instance, competitors or mates. The information should be useful to a great many species, not just birds, but also mammals and various other animals — species in which individuals keep each other informed by singing when they are apart.
Female Sexual Interference in the Smooth Newt, Triturus vulgaris vulgaris
Authors: Waights Verina
Published: May 2010

Competition between unmated females for males was observed in the smooth newt, T. vulgaris, during the early part of the breeding season. Females interfered at the spermatophore‐transfer stage of courtship, preventing a rival female from picking up the sperm mass. Interference often resulted in the rival female abandoning the courtship encounter. In many of the encounters (70%), the interfering female was inseminated. However, interference between females was not observed after the commencement of ovulation.

By contrast, the incidence of sexual interference between males was low during the preovulatory period and increased significantly post‐ovulation.

Sexual interference in newts and salamanders has previously only been observed between males. During the greater part of the breeding season, when females are ovipositing, eggs are the limiting resource and males compete for access to receptive females. However, this study suggests that early in the breeding season, prior to commencement of ovulation, the limiting resource may temporarily be sperm, due to the physiological constraint of spermatophore production. This may lead to female competition for mates.
Hormonal Correlates of Dominance and Starvation‐induced Aggression in Chicks of the Blue‐footed Booby
Authors: Mora Alejandra Nuǹz‐de la , Drummond Hugh , Wingfield John C.
Published: May 2010

In the blue‐footed booby (Sula nebouxii), the first‐hatched chick aggressively dominates its sibling and sometimes kills it when food is in short supply. To investigate the endocrine correlates of dominance‐subordinance and hunger‐induced agonism, we deprived 15–20‐d‐old single‐chick and two‐chick broods of food during 48 h by taping chicks' necks to prevent ingestion of parentally provided food (a protocol used previously and known to elicit escalated sibling fighting). We monitored weight and levels of circulating testosterone, oestradiol and corticosterone in deprived and normally fed broods comprising singletons, seniors (= dominants) and juniors (= subordinates), and observed behaviour to verify that aggression increased in deprived two‐chick broods. During the 2 d of fasting, experimental chicks lost on average 6% of their baseline weight. After normal feeding was reinstated, seniors and singletons recovered normal (control) weight, but juniors remained significantly lighter than controls. No testosterone was detected in any nestling, but baseline corticosterone level was 109% higher in juniors than in seniors or singletons, implying that elevated corticosterone in juniors is a consequence of social subordination and may facilitate submissive behaviour. Although there was evidence that aggression of seniors increased under food deprivation, the increase was not accompanied by the rise in levels of testosterone expected under the ‘Challenge hypothesis’ (Wingfield et al. 1990). This result implies that this hypothesis probably does not apply to booby nestlings in the context of starvation‐induced aggression. During the 2 d deprivation period, corticosterone levels of experimental chicks increased significantly, then declined to baseline levels a day after tapes were removed. The increase was probably due to the combined effects of starvation and frustration. We suggest that corticosterone could alter responsiveness of nestling blue‐footed boobies to external stimuli, resulting in more aggression by dominants and greater readiness of subordinates to submit.
Male‐male Interactions in Heterosexual and All‐male Wild Mountain Gorilla Groups
Authors: Robbins Martha M.
Published: May 2010

Variation in male dispersal and behavior patterns are components of intraspecific differences in social systems. A comparison of male behavior in different social settings can be useful for determining which behavioral mechanisms contribute to variability in social systems. Two heterosexual multimale groups and one all‐male group of mountain gorillas (Gorilla gorilla beringei) were observed for over 1100 h at the Karisoke Research Centre, Rwanda. Data on proximity patterns, dominance relationships, aggression, agonistic interventions, affiliation, and homosexual behavior were compared among the males in these groups to examine the influence of female presence, sex ratio, group size, and kinship on male—male interactions. Males in the all‐male group stayed closer together, affiliated more, exhibited more homosexual behavior, and were more aggressive toward each other than males in heterosexual groups. However, the males in heterosexual groups showed more wounding and more consistent dominance relationships. Kinship did not influence male‐male relationships in the all‐male group. The males in the heterosexual groups rarely interacted with one another; they may actively avoid close proximity to reduce aggression. Results suggest that the variable social system of mountain gorillas may be more strongly influenced by demographic factors, male‐female social relationships, and male‐male competition for mates than by any benefits of male‐male relationships.
Dominance Rank and Parental Investment in Swine (Sus scrofa domesticus)
Authors: Meikle Douglas B. , Drickamer Lee C. , Vessey Stephen H. , Arthur Robert D. , Rosenthal Thomas L.
Published: May 2010

Using domestic swine, we tested the general prediction from life history theory that females increase their investment in offspring with increasing age and parity. Because increased investment may have a greater beneficial impact on the lifetime reproduction of sons than daughters, we also tested the prediction that older females would invest more in sons than in daughters compared to younger females. Finally, we examined whether age‐ or parity‐related patterns of change in reproductive effort were associated with differences in the social dominance ranks of females. Female swine from a large number of domestic breeds were assigned to social groups, and their dominance ranks were determined based on the outcome of agonistic encounters. The prediction that older females produce larger litters was supported, but the increase was related only to age, not to parity. Across all ages, high‐ranking females produced a greater proportion of sons than low‐ranking females. Contrary to our prediction, there was no rank‐related change in the proportion of sons born with increasing age or parity. However, the mean body masses offspring born to high‐ranking females increased with increasing maternal age and parity, but this was not the case for offspring of low‐ranking females. Studies of free‐ranging groups of swine are needed to determine whether an increase in body mass at birth would have different effects on the reproduction of sons or daughters.
Aposematic Behaviour in the Striped Skunk,Mephitis mephitis
Authors: Lartviere Serge , Messier François
Published: May 2010

From April to August, 1993 to 1995, we studied the aposematic behaviour patterns of striped skunks,Mephitis mephitis, incidentally while ground‐tracking radio‐marked animals. During 2668 h of tracking, 207 defensive postures were displayed by 34 radio‐collared (27 females, 7 males) and 21 unidentified skunks. Skunks most often advertised their noxiousness using Tail‐up (69.1 % occurrence) and Stomp (17.4%). Encounters were frequently (42.5 %) terminated by the skunk running away from the source of disturbance. Most warning behaviour was directed at radio‐trackers (95.7 %), and the remainder was displayed to a variety of predatory and non‐predatory animals or objects. Stomp occurred more frequently in taller vegetation, where visual advertisement was limited. Reaction distance of skunks disturbed by observers (median = 6 m) was not affected by wind, movement or vegetation height. The small awareness circle and high tolerance of skunks to disturbance are consistent with the life history traits of aposematic animals.
Forms and Social Signal Value of Smiles Associated with Pleasant and Unpleasant Sensory Experience
Authors: Soussignan Robert , Schaal Benoist
Published: May 2010

Episodes of facial displays involving the zygomatic action (AU12: lip corner pulling or smiling) were selected from a large sample of children (n = 95) exposed to pleasant and unpleasant odours in the presence of an unfamiliar person in order to investigate potential differences in morphological, temporal patterning and social signal value of smiling.

In a first experiment, using the facial action coding system (FACS: Ekman & Friesen 1978), a considerable morphological flexibility of smiles was observed in relation to the subjects' hedonic experience. The facial configurations of smiling were formed by a number of actions in the upper (AU 4: brow lowering), middle (AU 9: nose wrinkling) and lower face (AU 14: dimpling, AU 15: lip comer depressing, AU 17: chin raising, AU 23: lip tightening) and the mouth was more often ‘closed’ in response to unpleasant odours. When exposed to pleasant odours, zygomatic action co‐occurred more frequently with an opening of the mouth (AUs 25, 26, 27) or with a raising of the cheeks (AU 6). An analysis of the temporal patterning of zygomatic actions showed that they occurred more rapidly, dropped off the face less abruptly with a stepped decrease, were less smooth, and were often associated with shorter gazes directed toward the examiner in response only to unpleasant odours. These findings suggested that a number of subjects might exert some control on their smiling while confronted with a presumed social constraint, namely the smelling of unpleasant odours in the presence of an unfamiliar person.

In a second experiment, the communicative value of smiling was investigated in a real‐time projection of 10 variants of smiling to a panel of receivers (n = 52). The Duchenne smile (AU 6 + 12 + 25) and smile with lips opening (12 + 25) provided more accurate information about the hedonic valence of the inhaled odour than did the other types of smiling. In contrast, the perceived valence of the facial displays simultaneously combining zygomatic action with muscular actions of the lower face (AUs 15, 17, 23) appeared more difficult to discriminate by untrained receivers. It was hypothesized that the senders displayed some forms of smiling possibly to mask their responsiveness to unpleasant odours in signalling ambiguous or incorrect information about their internal state to a recipient.
Acoustic Competition in Male Midwife Toads Alytes obstetricans and Alytes cisternasii: Response to Neighbor Size and Calling Rate. Implications for Female Choice
Authors: Bosch J. , Márquez R.
Published: May 2010

Effects of neighbor on male calling behavior was studied through playback experiments of synthetic calls to males of two species of midwife toads. The responses of resident males were scored considering two temporal parameters (call duration and calling rate) and one spectral parameter (dominant frequency). The sounds used for the playback tests included two levels of fundamental frequency (correlated with male size) and two levels of call repetition rate. In both species, resident males only changed their calling rate in the presence of an intruder, and the response was different for synthetic calls with two levels of dominant frequencies and with two calling rates. Resident size was not significantly correlated with the magnitude of the change in the calling rate. On the other hand, resident calling rate was significantly and positively correlated with the magnitude of the increase in calling rate of the stimulus. The maximum relative increase in calling rate was observed in A. cisternasii. In phonotaxis tests, females are preferentially attracted to calls emitted at a higher rate confirming the importance of changes in calling rate for female attraction.
Computer Simulation Suggests that the Spatial Distribution of Males Influences Female Visiting Behaviour in the River Bullhead
Authors: Bertorelle Giorgio , Bisazza Angelo , Marconato Andrea
Published: May 2010

It is known from previous laboratory studies that female choice in the river bullhead, Cottus gobio, is mainly influenced by the size of the male, and that the presence of eggs in the nest also plays a role. However, the process by which females visit and choose among prospective mates is still poorly understood. We examined eight possible tactics of female choice through computer simulation, and we compared their fit to the reproductive patterns observed in two natural populations. Neither of the tactics proposed for other species, nor combinations of them, were able to predict accurately the field data, although one of them (fixed threshold) provided a fairly good fitting. Conversely, a new model (cluster sampling), which takes into account the spatial distribution of males, produced for both populations a set of predictions on the male mating success not significantly different from the data recorded in the field. Under this model, females sample more males when males are clumped, thus reducing substantially, on the average, the ratio between the distance travelled before spawning and the number of sampled males. When models incorporated the preference for already mated males, good fitting was obtained if females preferred nests containing eggs not older than 36 h, a finding that agrees with field results.