Long-term influence of simulated territorial intrusions on dawn and dusk singing in the Winter Wren: spring versus autumn

Males of many songbird species have peaks of singing activity at dawn and dusk. Singing during those twilight periods can function in territory proclamation, and males are suggested to adjust song output to the level of intruder pressure. We used song playback during the breeding season to simulate intrusions into territories of male Winter Wrens (Troglodytes troglodytes) shortly after dawn. We then compared male singing behaviour during the dawn and dusk chorus before and 1 day after the simulated intrusion. One day after the playback, male Wrens increased their song output before sunrise, which confirms our results from a previous study on dawn singing in autumn territories. At dusk, on the evening following the playback, males slightly increased song output after sunset, but singing activity at dusk was generally very low. We found no significant changes of song output after sunrise, before sunset, and between 2 days of control without playback. These results are consistent with the hypothesis that dawn and dusk singing is important for territory defence in spring. Unlike in autumn, however, increased singing in spring at dawn and dusk could also serve to defend other resources such as fertile mates or to strengthen the pair bond after a territorial challenge. In comparison with the results on autumnal singing, male Wrens started singing earlier at dawn during the breeding season, and they generally sang more songs at dawn and immediately after playback. The increase in absolute numbers of songs sung in the morning after playback seemed greater in spring than in autumn; however, the proportional increase relative to overall song output was similar in both seasons.     

Stereotyped and non-stereotyped features of the temporal patterning of singing sessions in the ovenbird Seiurus auricapillus

Temporal patterning of recorded singing sessions of 26 different male ovenbirds Seiurus auricapillus (Fringillidae: Parulini) was analyzed computationally, in order to test whether differences among songs are potentially informative or merely reflect performance errors. Repeated songs within a singing session by a given male showed relatively little inter-individual variation in the duration of the song or in the number of units composing it, although these features varied substantially among individuals. On the other hand, within a session of singing by an individual male, the most variable and potentially informative aspect of temporal patterning was the relative placement of the peak amplitude within the song. These results support the hypothesis that diversity in the vocalization sessions of oscine passerines can be produced by other means than the use of a varied song repertoire, even in a species like the ovenbird that uses just one song type. Because variation among song was focused on a single feature, performance errors are an unlikely explanation, suggesting that the temporal patterning of singing sessions may play an informative role, such as the minimization of habituation on the part of receivers.     

Song environment affects singing effort and vasotocin immunoreactivity in the forebrain of male Lincoln's sparrows

Male songbirds often establish territories and attract mates by singing, and some song features can reflect the singer's condition or quality. The quality of the song environment can change, so male songbirds should benefit from assessing the competitiveness of the song environment and appropriately adjusting their own singing behavior and the neural substrates by which song is controlled. In a wide range of taxa, social modulation of behavior is partly mediated by the arginine vasopressin or vasotocin (AVP/AVT) systems. To examine the modulation of singing behavior in response to the quality of the song environment, we compared the song output of laboratory-housed male Lincoln's sparrows (Melospiza lincolnii) exposed to 1 week of chronic playback of songs categorized as either high or low quality, based on song length, complexity, and trill performance. To explore the neural basis of any facultative shifts in behavior, we also quantified the subjects' AVT immunoreactivity (AVT-IR) in three forebrain regions that regulate sociosexual behavior: the medial bed nucleus of the stria terminalis (BSTm), the lateral septum (LS), and the preoptic area. We found that high-quality songs increased singing effort and reduced AVT-IR in the BSTm and LS, relative to low-quality songs. The effect of the quality of the song environment on both singing effort and forebrain AVT-IR raises the hypothesis that AVT within these brain regions plays a role in the modulation of behavior in response to competition that individual males may assess from the prevailing song environment.     

Variation in singing behaviour among morphs of the sand field cricket,Gryllus firmus

1. Trade‐offs play a fundamental role in the evolution of many traits. 2. In wing‐polymorphic field crickets, the long‐winged morph can disperse from unfavourable environments, but has lower reproductive success than the short‐winged morph, because of costs associated with flight capability. 3. However, long‐winged individuals may minimise costs in favourable environments by histolysing their flight muscles and becoming flightless. 4. Few studies have examined how flight‐muscle histolysis affects male signalling and mate attraction. 5. We examined differences in singing activity and song characteristics among the flightless (short‐winged and histolysed long‐winged) and the flight‐capable male morphs, and female preferences for male song, in the sand field cricket. 6. We found: (i) both flightless morphs sang more than the flight‐capable morph, (ii) song characteristics varied among the three morphs, and (iii) females preferred songs characteristic of the long‐winged morphs. 7. Histolysis should increase mating success of long‐winged males because it increases singing activity. 8. Histolysed long‐winged males may have higher mating success than short‐winged males as they sing as frequently but produce more attractive songs. 9. Therefore, plasticity within the long‐winged morph may reduce costs of maturing in environments from which dispersal is not advantageous; non‐flying morphs may be pursuing different reproductive tactics.     

Courtship behaviour in Japanese macaques during heterosexual and homosexual consortships

Female Japanese macaques (Macaca fuscata) in the Arashiyama population near Kyoto, Japan, are unusual, in that they exhibit what many would consider to be male-typical sexual characteristics. Specifically, they mount other females within the context of temporary, but exclusive, sexual relationships (i.e., homosexual consortships) and they sometimes exhibit a preference for female sexual partners, even when given the choice of a sexually motivated male alternative. In this study, we examined whether female Japanese macaques also exhibited male-typical patterns of courtship behaviour during homosexual consortships. Data were collected on courtship behaviour during heterosexual and homosexual consortships in free-ranging Japanese macaques from the Arashiyama (Japan) population. We analyzed the occurrence of 12 different courtship behaviours during 3374 heterosexual inter-mount intervals and 1412 homosexual inter-mount intervals. Sex differences between heterosexually consorting males and females existed for only two of the 12 courtship behaviours we investigated: inclined-back presentations and sexual vocalizations. Dominant and subordinate homosexually consorting females were sex-typical in their expression of inclined-back presentations and sexual vocalizations. Consequently, facultative same-sex sexual partner preference, mounting and consortships do not co-occur with male-typical patterns of courtship behaviour in female Japanese macaques.     

Male courtship song and female preference variation between phylogeographically distinct populations of Drosophila montana

Understanding the variation within and between populations in important male mating traits and female preferences is crucial to theories concerning the origin of sexual isolation by coevolution or other processes. There have been surprisingly few studies on the extent of variation and covariation within and between populations, especially where the evolutionary relationships between populations are understood. Here we examine variation in female preferences and a sexually selected male song trait, the carrier frequency of the song, within and between populations from different phylogeographic clusters of Drosophila montana. Song is obligatory for successful mating in this species, and both playback and field studies implicate song carrier frequency as the most important parameter in male song. Carrier frequency varied among three recently collected populations from Oulanka (Finland), Vancouver (Canada), and Colorado (central United States), which represent the main phylogeographic groups in D. montana. Males from Colorado had the most distinct song frequency, which did not follow patterns of genetic differentiation. There was considerable variation in preference functions within, and some variation between, populations. Surprisingly, females from three lines from Colorado seem to have preferences disfavoring the extreme male trait found in this population. We discuss sources of selection on male song and female preference.     

Female choice in the sedge warbler Acrocephalus schoenobaenus: multiple cues from song and territory quality

Recent models of animal signalling emphasize the evolution of complex displays containing ''multiple messages''. A variety of potential cues used in female choice were investigated during a three-year field study of the sedge warbler, Acrocephalus schoenobaenus. Twelve possible cues were investigated, and three were found to have a significant influence upon pairing date. Two were different measures of song (repertoire size and song flighting) and one a measure of territory (territory size). Repertoire and territory size had a significant influence on pairing date in all three years, and song-flighting in two. The three cues were not intercorrelated and so had independent effects upon pairing date. We suggest that females select males upon multiple cues as these reflect different aspects of male and territory quality.     

Flocking behaviour in the twilight ascents of Common Swifts Apus apus

Among the many unique flight behaviours of Common Swifts Apus apus, the most puzzling may be their ascents to high altitudes during both dusk and dawn. Twilight ascents have been hypothesized to be functionally related to information acquisition, including integration of celestial orientation cues, high‐altitude visual landmarks and sampling of weather conditions. However, their exact purpose remains unknown. We tracked Common Swifts with tracking radar at their breeding grounds in southern Sweden, and present evidence that during the dusk ascent and dawn descent they often occur in flocks, whereas during the dusk descent and dawn ascent phase they do not. This flocking behaviour suggests that swifts may benefit from conspecific interactions during twilight ascents and descents, possibly through more robust cue acquisition and information exchange in groups, or extending social behaviour also seen in screaming parties before dusk.     

Menstrual cycle phases and female receptivity to a courtship solicitation: an evaluation in a nightclub

Previous research has demonstrated that female behaviors toward men or sexual interest are different across the menstrual cycle. However, women's receptivity to an explicit courtship solicitation still remained in question. In a field experiment, 20-year-old women were approached by 20-year-old male confederates in nightclubs and solicited to dance during the period when slow songs were played. A survey was administered to the women in order to obtain information about the number of days since the onset of previous menses. It was found that women in their fertile phase agreed more favorably to the dance request than women in their luteal phase or in their menstrual phase.     

The song structure and seasonal patterns of vocal behavior of male and female bellbirds (Anthornis melanura)

The bellbird (Anthornis melanura) is a honeyeater endemic to New Zealand, which uses song to defend breeding territories and/or food resources year round. Both sexes sing and the song structure and singing behavior have not yet been quantified. The number of song types, spectral structure, repertoire size, and singing behavior of male and female bellbirds was investigated for a large island population. Song types differed between the sexes with males singing a number of structurally distinct song types and females producing song types that overlapped in structure. Singing behavior also differed between the sexes; males often sung long series of songs while females sung each song at relatively long and variable intervals. Singing by both sexes occurred year round but the frequency of male and female singing bouts showed contrasting seasonal patterns. The frequency of female singing bouts increased as the breeding season progressed, whereas male singing bouts decreased. In contrast to almost all studied passerines, female bellbirds exhibited significant singing behavior and sung songs of complex structure and variety that parallel male song. These results provide a quantitative foundation for further research of song in bellbirds and in particular the function of female vocal behavior.     

Immediate and long-term effects of testosterone on song plasticity and learning in juvenile song sparrows

Steroid sex hormones play critical roles in the development of brain regions used for vocal learning. It has been suggested that puberty-induced increases in circulating testosterone (T) levels crystallize a bird's repertoire and inhibit future song learning. Previous studies show that early administration of T crystallizes song repertoires but have not addressed whether new songs can be learned after this premature crystallization. We brought 8 juvenile song sparrows (Melospiza melodia) into the laboratory in the late summer and implanted half of them with subcutaneous T pellets for a two week period in October. Birds treated with T tripled their singing rates and crystallized normal songs in 2 weeks. After T removal, subjects were tutored by 4 new adults. Birds previously treated with T tended toward learning fewer new songs post T, consistent with the hypothesis that T helps to close the song learning phase. However, one T-treated bird proceeded to learn several new songs in the spring, despite singing perfectly crystallized songs in the fall. His small crystallized fall repertoire and initial lag behind other subjects in song development suggest that this individual may have had limited early song learning experience. We conclude that an exposure to testosterone sufficient for crystallization of a normal song repertoire does not necessarily prevent future song learning and suggest that early social experiences might override the effects of hormones in closing song learning.     

Male and female rufous‐and‐white wrens do not match song types with same‐sex rivals during simulated territorial intrusions

In birds with song repertoires, song‐type matching occurs when an individual responds to another individual's song by producing the same song type. Song‐type matching has been described in multiple bird species and a growing body of evidence suggests that song‐type matching may serve as a conventional signal of aggression, particularly in male birds in the temperate zone. Few studies have investigated song‐type matching in tropical birds or female birds, in spite of the fact that avian biodiversity is highest in the tropics, that female song is widespread in the tropics, and that female song is the ancestral state among songbirds. In this study of rufous‐and‐white wrens Thryophilus rufalbus, a resident neotropical songbird where both sexes sing, we presented territorial males and females with playback that simulated a territorial rival producing shared and unshared songs. In response, both males and females sang matched song types at levels statistically equal to levels expected by chance. Furthermore, males and females exhibited similar levels of aggression and similar vocal behaviours in response to playback of both shared and unshared songs. These results indicate that rufous‐and‐white wrens do not use song‐type matching in territorial conflicts as a conventional signal of aggression. We discuss alternative hypotheses for the function of song‐type sharing in tropical birds. In particular, we point out that shared songs may play an important role in intra‐pair communication, especially for birds where males and females combine their songs in vocal duets, and this may supersede the function of song‐type matching in some tropical birds.     

果蝇nasuta亚群求爱歌的种间识别与进化遗传学研究

果蝇ｎａｓｕｔａ亚群由１４个种、亚种和分类群组成,广泛分布于印度－太平洋区域。本文首次记录了ｎａｓｕｔａ亚群种的求爱歌,测量了脉冲歌时域模式的参数：脉冲串间隔（ＩＢＩ）、脉冲间隔（ＩＰＩ）、脉冲串时间长度（ＰＴＬ）、每个脉冲串的脉冲数（ＰＮ）、脉冲时间长度（ＰＬ）、波动周期时间长度（ＣＬ）。采用计算机声谱分析技术,作出求爱歌信号的三维数字功率谱图,进行频率分析。发现Ｄ．ｐｕｌａｕｎａ和Ｔａｘｏｎ－Ｆ不发出求爱歌声信号,视觉在交配中可能起重要作用。对其余种、亚种和分类群的求爱歌分析表明,ｎａｓｕｔａ亚群种的求爱歌分为脉冲歌和正弦歌。对部分种的正反交Ｆ１求爱歌分析表明,脉冲歌时域参数,如ＩＰＩ平均值为Ｘ染色体连锁或常染色体多基因控制,正弦歌频率偏向母方。根据不同种、亚种和分类群脉冲歌的时域模式构建ｎａｓｕｔａ亚群的系统树,对亚群中不同种、亚种和分类群的亲缘关系进行讨论。     

稻水象甲(Lissorhoptrus oryzophilus Kuschel)滞育征候群中的飞行行为

１９９４～１９９６ 年对浙江省双季稻区稻水象甲（ Ｌｉｓｓｏｒｈｏｐｔｒｕｓ ｏｒｙｚｏｐｈｉｌｕｓ Ｋｕｓｃｈｅｌ）飞行行为的研究表明,稻水象甲飞行扩散的行为特征是：①长时间的起飞准备和不高的起飞成功率,每晚的迁出率只有三分之一左右;②卵巢、飞行肌呈季节性消长而无局地飞行（ｔｒｉｖｉａｌｆｌｉｇｈｔ）;③飞行速度不高,飞行能力不强,且风力稍大便无法起飞,一般情况下不会形成远距离自然扩散。因此,严格控制人为传带是控制疫区扩大的有效途径。     

Heat transfer and the energetic cost of singing by canaries <Emphasis Type="Italic">Serinus canaria</Emphasis>

Sexually selected displays, such as male passerine bird song, are predicted to be costly. However, most measurements calculated the rate of oxygen consumption during singing using respirometry have shown that bird song has a low energetic cost. Since birds are reluctant to sing when enclosed inside a respirometry chamber, the energetic cost of singing could differ from that under more normal circumstances. We used heat transfer modelling, based on thermal images, to estimate the energetic cost of singing by canaries (Serinus canaria) that were not enclosed in respirometry chambers. Metabolic rate calculated from heat transfer modelling was 0.70±0.02 W (N=10 birds) during singing, which was 14±5% greater than during standing (0.62±0.02 W). The energetic cost of singing did not differ significantly from that measured previously using respirometry when we took into account that birds sang for a greater proportion of the time during the current experiments. These conclusions were not sensitive to potential errors in the heat transfer model. Heat transfer modelling would be especially useful to obtain measurements of the energetic cost of activities that animals do not perform readily inside respirometry chambers, such as singing in birds.     

稻水象甲(Lissorhoptrus oryzophilus Kuschel)滞育征候群中的飞行行为

１９９４－１９９６年对浙江省双季稻区稻水象甲（ＬｉｓｓｏｒｈｏｐｔｒｕｓｏｒｙｚｏｐｈｉｌｕｓＫｕｓｃｈｅｌ）飞行行为的研究表明,稻水象甲飞行扩散的行为特征是：（１）长时间的起飞准备和不高的起飞成功率,每晚的迁出率只有三分之一左右,（２）卵巢,飞行肌呈季节性消长而无局地飞行（ｔｒｉｖｉａｌｆｌｉｇｈｔ）;（３）飞行速度不高,飞行能力不强,且风力稍大便无法起飞,一般情况下不会形成远距离自然扩散,因此     

Male behaviour and female choice: Mate selection in the wren?

The European wren is frequently polygynous. Males occupy exclusive territories within which they spend much time displaying and building nests. They lead females to their nests in courtship. Males building the most nests during a season also make the most breeding attempts. Data collected in one of two years suggested that individual females may show a preference for males with the largest number of complete but vacant nests. There was no consistent correlation between male display behaviour and female mate choice. Data on breeding success may suggest why polygyny is adaptive for both males and females in this species.     

Plasticity in singing effort and its relationship with monoamine metabolism in the songbird telencephalon

Factors intrinsic or extrinsic to individuals, such as their quality or the quality of competition in their social environment, can influence their communication signaling effort. We hypothesized that telencephalic monoamine secretion mediates the effects of a male's own quality and quality of his social environment on his sexual signaling effort. The duration of a male European starling's (Sturnus vulgaris) principal sexual signal, his song, positively correlates with several aspects of his quality, including his reproductive success, immunocompetence, and ability to attract mates. Therefore, the length of songs to which he is exposed reflects, in part, the quality of competition in his social environment. We manipulated the quality of the competitive environment by exposing male starlings to long or short songs for 1 week. We measured the length of songs produced by experimental males to gauge their quality, counted the number of songs they produced to gauge singing effort, and quantified telencephalic monoamine metabolism using high‐pressure liquid chromatography. Singing effort increased with the length of the males' own songs and with the length of songs to which we exposed them. Norepinephrine metabolism in area X of the song control system was negatively correlated with the subjects' mean song length and singing effort. Serotonin metabolism in the caudomedial mesopallium of the auditory telencephalon increased with the length of songs to which we exposed the subjects and with their singing effort. This raises the hypothesis that serotonin and norepinephrine secretion in the telencephalon help mediate the effects of extrinsic and intrinsic factors on signaling effort. © 2009 Wiley Periodicals, Inc. Develop Neurobiol, 2010