bluuebunny/crossref_metadata_2025 huggingface dataset:
Perceptual Imprinting: Genetically Variable Response Tendencies, Selective Learning, and the Phenotypic Expression of Colour and Pattern Preferences in Quail Chicks (C. Coturnix Japonica)
Authors: Kovach Joseph K.
Published: April 2008

Eighteen generations of bidirectional genetic selection of quail for early approach preferences between two colours resulted in nearly perfect preferences of blue over red in one and red over blue in another genetic line. This selection also enhanced, over performance of unselected controls, the preference of a grated over a dotted pattern in both genetic lines. In the choices between composite stimuli colour effects dominated over pattern effects. Imprinting to blue or red resulted in robust modification of colour choices. Imprinting to composite stimuli of colours and patterns likewise modified colour but did not change or only marginally changed pattern choices, suggesting colour dominance in learning as well. However, imprinting to achromatic patterns also left pattern choices unchanged, or modified them only marginally. Joint imprinting to blue and red in variable temporal ratios modified colour choices in ways that reflected influences from both the genetically manipulated initial preference values and the exposure dosages of particular colours. The genetically manipulated preference values and preference combinations of stimuli thus influenced the outcome of imprinting by setting the baselines upon which selective learning acted, by underlying perceptual dominance of particular stimuli, and by facilitating or inhibiting the phenotypic expression of what had been learned.
The Significance of Song Variation in a Population of Darwin's Finches
Authors: Grant B.R.
Published: April 2008

Males of Geospiza conirostris, the large cactus finch, on Isla Genovesa, Galápagos, sing a single, precisely copied song. There are two song types in the population, and these are sub-divided into 3 and 5 discrete song sub-types respectively. Adult males sing only one song sub-type throughout life. Sons sing the same song sub-type as their fathers' and do not copy the songs of either natal or breeding territory neighbours. Significantly more of the males holding territories with neighbours of unlike (heterotypic) song type obtain a female than males in territories with no heterotypic neighbour. Pairs in territories with a heterotypic neighbour fledge significantly more young than do pairs in territories with no heterotypic neighbour. Significantly more of those young born on territories with a heterotypic neighbour, that survive to become adults, obtain a mate, than do those surviving young born on territories with no heterotypic neighbour. The data are consistent with the hypothesis that the relative greater importance of song for species recognition in this population has made it advantageous for males to have a single, short, distinct, precisely copied and stable song. The necessity for recognizing both song types as conspecific has produced a unique mating pattern which favours pairs in territories with a heterotypic song neighbour. This allows young to associate visual and auditory cues of father and neighbouring male during the short period of imprinting. A small effective population size, combined with the observation that no female has been known to mate with a male of the same song sub-type as her father's, suggests a possible kin recognition system to avoid inbreeding.
Information Exploitation By Downy Woodpeckers in Mixed-Species Flocks
Authors: Sullivan Kimberly A.
Published: April 2008

Downy woodpeckers (Picoides pubescens) benefit from foraging in mixed-species winter flocks by decreasing their vigilance level and increasing their feeding rate. I investigated one mechanism, auditory cues, downy woodpeckers use to obtain information on the presence of other flock members and potential predators. Experiments with predator models and with recorded alarm calls and contact calls from flock members yielded the following results. Downy woodpeckers use the contact calls of other flock members to assess the presence of flocks members. Woodpeckers foraging alone but with the recorded contact calls of flock members showed lower vigilance levels and higher feeding rates than woodpeckers foraging alone with no recordings or with the control recordings. Woodpeckers respond to the other species' alarm calls as an indication of potential predators and also to their contact calls as an all clear signal afterwards. Downy woodpeckers decreased their vigilance levels and resumed foraging faster when the contact calls followed the presentation of predator models or alarm calls than when these were presented alone.
Loud Calls of the Gibbon (Hylobates Lar): Repertoire, Organisation and Context
Authors: Raemaekers Jeremy J. , Raemaekers Patricia M. , Haimoff Elliott H.
Published: April 2008

We describe and illustrate with sonograms the loud calls of a monogamous, territorial ape, the lar gibbon (Hylobates lar). We attempt an overview of its repertoire of loud calls, their organisation, contexts and functions. The description is based on a two year study of a wild population in Khao Yai National Park, Thailand. We distinguish seven classes of call bout: male solo, male dispute calls, female solo, normal duet by bonded pair, ooaa duet (similar to normal duet, but more infectious to other groups), disturbed calls and contact calls. The organisation of the normal duet is described in detail, showing the coordination of the sexes, the development of the male part through the call bout, and the presence of individual and pair differences. The discussion considers the possible functions of duets, of male solos, and of disturbed calls given in reaction to man.
Comparative Aspects of Behavioural Development in Two Species of Free-Living Hyrax
Authors: Caro T.M. , Alawi R.M.
Published: April 2008

Four measures of play behaviour of two species of sympatrically living hyrax Heterohyrax brucei and Procavia johnstoni, were studied on three rocky outcrops or kopjes in the Serengeti National Park, Tanzania. The amount of play shown by young of both species, born in 1981, declined during the study. Procavia played at a significantly higher rate than did Heterohyrax throughout this period. This was true even after differences in species' activity were taken into account. Procavia did not show higher rates of behaviour because they had more conspecifics with which to interact. The young of both species of hyrax played with members of the other species; Procavia significantly more so than Heterohyrax. The high rates of interspecific play in Procavia could be explained by their relatively low numbers compared to Heterohyrax on one kopje, but on the other two kopjes they appeared to actively seek out interactions with Heterohyrax. Interspecific differences in the behaviour of young of the two hyrax species were then related to interspecific differences in their adult behaviour. Adult Procavia exhibited higher scores than adult Heterohyrax on three measures of behaviour, reflecting corresponding differences in the play of the young of these species. These differences were found even when adult behavioural scores had been standardised for activity. Furthermore, adult Procavia showed more interspecific behaviour than adult Heterohyrax; a result similar to that found in the play of the young of the two species of hyrax.
Courtship Behaviour in the Melanogaster Species Sub-Group of Drosophila
Authors: Cobb Matthew , Connolly Kevin , Burnet Barrie
Published: April 2008

Descriptions of courtship behaviour are given for seven members of the melanogaster species sub-group: Drosophila melanogaster, simulans, mauritiana, yakuba, teissieri, erecta and orena. A male wing behaviour not previously reported, wing extension, was observed in either 1- or 2-wing variants in all species except melanogaster and simulans. Male wing rowing, previously reported in mauritiana and teissiri, was seen in 1- or 2-wing variants in all species except melanogaster and orena. D. teissieri showed the most extreme form of wing rowing, and yakuba the widest variety of angles of wing vibration. Tapping by the male was observed in all species except simulans and mauritiana, but not always at the onset of courtship and not in every courtship. Extrusion in virgin females was observed in melanogaster and erecta, and abdomen extension in female simulans, yakuba, teissieri and orena. Female wing behaviours were observed in all species except simulans. Wing extension and wing rowing are distinct from vibration and scissoring (behaviours they strongly resemble). There is strong a behavioural connection between these pairs of behaviours, in that wing extension often leads to vibration, wing rowing to scissoring, and vice versa. A mechanical function for licking is proposed, following observation of long duration licking in yakuba. The function of licking is thought to be elevation of the female's abdomen, preparatory to copulation. The relationship between the seven species based on their courtship behaviours was examined using principal coordinates analysis. This suggests that the two cosmopolitan species, simulans and melanogaster, differ most widely in their courtship behaviour, with mauritiana being the most similar to simulans. This finding is assessed in relation to the ecology of the seven species, the role of courtship behaviour in speciation, and the reliability of inferences from behaviour in phylogenetic analyses.
Vervet Monkey Alarm Calls: Manipulation Through Shared Information?
Authors: Cheney Dorothy L. , Seyfarth Robert M.
Published: April 2008

High-ranking male and female vervet monkeys in Amboseli National Park alarm-call at higher frequencies than do low-ranking males and females. This correlation between rank and alarm-calling does not occur because high-ranking animals have more offspring or close kin than low-ranking animals. Similarly, high-ranking animals do not seem to have greater opportunities to spot potential predators; they do not scan the habitat more than low-ranking animals, nor are they more likely to be in the forefront of group progressions. It seems possible that low-ranking animals may spot predators as often as high-ranking animals, but that they do not always alert other group members to approaching danger. As a further test of the possibility that monkeys may vary the rate of alarm-calling depending on social contexts, an experiment was conducted on captive vervet monkeys in which adult females were presented with a predator in the presence of either their offspring or an unrelated juvenile. Adult females alarm-called significantly more often when with their offspring than with unrelated juveniles. A similar experiment conducted on adult males showed that males alarm-called at higher rates in the presence of adult females than in the presence of other adult males. The results of both experiments and observations suggest that monkeys may vary the rate at which they warn others of danger. The withholding of information may be an effective means to deceive others, because it is relatively difficult to detect cheaters. The possible advantages of selectivity in alarm call production are discussed.
Sexual Selection in the Spring Peeper, Hyla Crucifer (Amphibia, Anura): Role of the Advertisement Call
Authors: Forester Don C. , Czarnowsky Richard
Published: April 2008

1. The advertisement call of the spring peeper exhibits significant variation in each of the four parameters examined: intensity, duration, frequency, repetition rate. 2. In playback experiments involving calls differing in a single parameter, females exhibited preference for loud calls, calls with a rapid repetition rate and low frequency calls. 3. Although we had hypothesized that females would prefer long calls to short calls, they did not. We attribute this lack of preference to unanticipated differences in the sound envelope of the two experimental calls. 4. Non-random choice by females during playback experiments may have been in response to the conspicuousness of the male call, or to encoded clues pertaining to male fitness. 5. Call repetition rate is positively correlated with body size (snout-vent length) while frequency is negatively correlated. 6. Anuran growth is thought to be indeterminate, so that larger males are typically older males. As a consequence of having survived longer, large males may be more fit. 7. Since females exhibited a preference for call parameters which were correlated with body size, we had anticipated that large males would experience differential mating success in nature. A comparison of amplexed and non-amplexed males over a three year period revealed no intergroup size difference. 8. We conclude that while females may select calls indicative of size, and perhaps fitness, during laboratory trials, such choices are likely more difficult in an active breeding congregation where acoustical interference and competition may tend to obscure call variation. 9. Finally we report the presence of small, non-calling satellite males and suggest that their success as sexual parasites may have influenced the size relationship between amplexed and non-amplexed males in our study.
Making the Decision To Continue the Fight or To Flee
Authors: Mosler Hans-Joachim
Published: April 2008

Males of Haplochromis burtoni have ritualized fights with physical contact and they assess the relative persistence of their opponents by their reactions, following their own behavior patterns. For this the fighter has to know which reactions have a typical winner or loser meaning and thus which reactions could point at more or less persistence. I evaluated the meanings out of a preliminary data sample of 27 fights by calculating information values, with a formula developed, for each reaction in each fighting stage. In general, it seems that Displaying Long, that is, being Rammed for a long time has a typical winner meaning, indicating more persistence. The hypothetical reactions were tested with a second sample. In 20 out of 23 fights the number of typical winner reactions of the winner is greater, up to the last fighting stage. Because this difference is only in the last fighting stage significant, I postulated a "Critical Fighting Stage". The fighter comes into this stage when he feels a little weariness. From this stage on, and not before, his assessment of his opponent should become relevant for him. A fighter with this strategy has three advantages : 1. Each bluff will be ineffective if it does not happen in the "Critical Fighting Stage". Therefore, a fighter should by no means show he is in this stage. 2. A fighter cannot give any information about how long he will fight, because he does not know it himself. 3. He does not know it himself because he adapts his persistence to the fighting of his opponent. ` The results brought the following new aspects to sociobiological hypotheses: 1. A bimodal function of the ESS nearly agreed with the frequency distribution of the duration of 50 fights. I tried to describe the suitable penalty function on the basis of my observations. 2. I found that the assessment improved with the fighting stages. Therefore, the information acquired in each stage is not constant. 3. The concept of the "Critical Fighting Stage" allows for the best adaptation of a fighter's persistence to the fighting of his opponent.
Acquisition of Predator Information By Active and Passive Mobbers in Ring-Billed Gull Colonies
Authors: Conover Michael R.
Published: April 2008

Mobbing flocks of ring-billed gulls consisted to two groups: individuals whose nests were near to and threatened by the predator (active mobbers) and others from more distant parts of the colony (passive mobbers). This study examined whether either group can learn about the predator from their mobbing experience. The active mobbers quickly habituated to a human intruder near their nests when the intruder was inactive and empty-handed. Conversely, the gulls responded with a greater flock size and flight distance and fewer swoops when the intruder was holding an adult gull. These response patterns persisted even after the adult gull was removed and the human intruder reappeared alone. When the human intruder held a chick, the gulls approached more closely and swooped more than when the intruder held an adult gull. To examine whether passive mobbers learned anything about the human intruder during the earlier tests, the intruder (now empty-handed) moved to a new location 50 m away and repeated the test. The gulls at these sites, also were significantly less wary than naive gulls of the human intruder following tests in which the intruder was empty-handed, and more wary following tests in which the intruder held an adult gull. Because the earlier test sites were situated so that they could not be seen from the ground at the 50 m sites, a gull at the latter sites could only have learned details about the intruder if it or some of its neighbors had become mobbers. Gulls whose nests were 100 m from an owl model or human intruder learned less about it than gulls at 50 m: perhaps because fewer gulls became passive mobbers as the distance between them and the owl or intruder increased. Costs of becoming a passive mobber include an energetic and time cost and some risk of personal injury due to mid-air collisions with other gulls. The number of passive mobbers increased on breezy days perhaps because strong updrafts on those days reduced the energetic costs of flight within the colonies (and hence of being a mobber). These results support the hypothesis that the gulls' predator-attraction behavior allows them to learn about predators from watching predator-conspecific interactions. The opportunity to witness such interactions and learn about predators may be an important secondary benefit of coloniality for these birds.
Structure and Causation of the Dominance Hierarchy in a Flock of Bar-Headed Geese (Anser Indicus)
Authors: Lamprecht JÜRG
Published: April 2008

In a flock of tame, free-flying bar-headed geese (Anser indicus) the structure, stability and causes of the dominance hierarchy among different types of social units were studied. 1. In accordance with field results of other authors, families proved dominant over pairs, pairs over unpaired birds, and single males dominated single females. Single females with young ranked between families and pairs in this study, and lone breeding males whose females were incubating ranked between pairs and unpaired individuals. Contrary to some field studies, no rank differences were found between different-sized families. 2. The dominance value of pairs in winter correlated with subsequent fledging success, and there was some casual evidence that high-ranking males are more likely to obtain a mate. This would result in relating high rank to families, medium rank to pairs and low rank to unpaired birds. Yet as temporarily leaving the mate was promptly followed by a drop in rank and successful breeding by a rise in rank, the social context seems a major cause, and only to a minor extent a consequence of dominance rank. 3. Age correlated more strongly with a pair's rank in winter than weight, tarsus length and upper beak length. Rank in summer correlated highly with rank in the following winter. A positive feedback system age - dominance - fledging success-higher dominance-fledging success' is suggested which could account for the 'delayed breeding' common in geese and swans. 4. In pairs or families male age correlated more strongly than female age with winter dominance. Most opponents were displayed by the male alone, and only the male of a pair got involved in highest intensity aggression (wing-beat fighting). The widowed female of one high-ranking pair was low-ranking in subsequent years when paired with a young low-ranking male. The evidence suggests that the gander alone determines a family's or pair's rank. 5. There was no indication of a positive co-operative effect achieved by joint aggression. Comparison of frequencies of aggressive acts and postures between birds in different social contexts suggested that the presence of the mate and/or offspring increases fighting motivation, thus explaining the dependence of rank on the social context. 6. The stability of dyadic dominance relationships between social units was greater between than within social classes. The hierarchy of social classes can be explained by geese signalling their degree of fighting motivation to each other. Individual recognition of members of other social units seems of minor importance for the hierarchy even in this stable flock.
Temporal Patterns of Feeding Behaviour in Free-Ranging Horses
Authors: Mayes Eleanor , Duncan Patrick
Published: April 2008

Feeding was patterned into meals separated by intervals of non-random length. Meal length, which showed a marked circadian rhythm, was positively correlated with the length of the preceding interval (preprandial correlation) in all seasons except the summer. This result implies the existence of a control mechanism which maintained gut-fill high. The organisation of feeding within meals (length of feeding, standing and walking bouts) did not vary consistently between vegetation types, but was strongly influenced by the activity of biting flies.
Acoustic Recognition Between Mother and Cubs in Raccoons (Procyon Lotor)
Authors: Sieber Otto J.
Published: April 2008

Two vocalizations, utilized by raccoon (Procyon lotor) mothers ("chitter") and their dependent cubs ("whistle") to establish and maintain contact among each other, are studied in captive groups containing a total of 6 mothers and their 23 cubs. The paper describes frequency of occurrence of the calls, contexts of the callers, individual variation in the call's structure and the responses of the callees both in uncontrolled situations and in playback experiments. Maternal chitters are most frequently used during the month following the first excursion of the cubs from the litter den by females approaching the cubs or leading them to the food. The frequency of whistling in cubs is high during the nestling period and decrease when they become mobile. The main context of whistling in the cub-mother relationship is answering maternal chitters. Mobile cubs follow their chittering mother silently. The chitters of 4 females differ individually, the main distinctive feature being frequency and pulse rate. The whistles of 12 cubs are individually distinctive, too; duration and frequency measures differ most between individuals. Hence, mothers and cubs have the potential for individual acoustic identification. Seven-week-old nestlings, tested in an experimental arena with successive playbacks, answered maternal chitters on average more often and faster than alien ones, warning grunts or a noise. Mobile cubs approached maternal chitters more often when tested in simultaneous playback experiments. Only 2 of 6 females, however, confronted with whistle-playbacks of their own vs alien cubs in their cages, responded more strongly to calls of their offspring. Results indicate that raccoons may be capable of recognizing family members by acoustic cues alone on a familiar vs strange basis. Advantages of using vocalizations in mother-young relationship and of the potential for acoustic identification and recognition in a solitary mammal are discussed.
The Functional Significance of Vocal Mimicry in Song
Authors: Hindmarsh Andrew M.
Published: April 2008

The results of a study of starling vocal mimicry are summarised and discussed in relation to various possible functional explanations of mimicry. Only one, a hypothesis based on sexual selection, is not rejected outright and even this was seen to have problems. A dif ferent approach yielded a causal hypothesis based on mistakes made during song learning. This causal hypothesis is consistent with all known features of starling mimicry, and can readily be extended to other species, but is probably not consistent with any of the candidate functional hypotheses, including the one based on sexual selection. It is tentatively concluded that there is no additional functional explanation of starling vocal mimicry.
Similar Behaviour and Colour Patterns in 3 Not Closely Related Barbus Species. Is Evolutionary Convergence a Likely Explanation?
Authors: Kortmulder K.
Published: April 2008

The main theoretical issue of this paper is the interpretation of the close similarity of the total behaviour and colour patterns of 3 not closely related Barbus species. The case for evolutionary convergence is easy if the total pattern of each species is interpreted as a collection of evolutionary adaptations to the species' natural habitat. The thorough similarity of the 3 species must then be ascribed to key similarities between their natural habitats. However, it is argued that another interpretation is possible, in which the diverse traits cohere causally and have been acted upon as one whole by natural selection. In the extreme case of this alternative interpretation, the case for convergence may still be won, but it is a Pyrrhic victory: convergence has lost much of its usual meaning. Apart from the above discussion, the reproductive behaviour and spawning colours of the 3 species are described and compared in some detail. Possible functional reasons for a relatively small difference as to the degree of sexual colour dimorphism are discussed in relation to eye sizes and visual discrimination.
Acoustic Communication in Woodhouse's Toad (Bufo Woodhousei)
Authors: Sullivan Brian K. , Leek Marjorie R.
Published: April 2008

We investigated changes in calling behavior of individual male Bufo woodhousei in response to playback of natural and synthetic acoustic stimuli. Males lowered their call rates and avoided acoustic overlap with all stimuli centered at 1.4 kHz; only a high frequency (3.8 kHz) stimulus was ineffective. Even filtered noise centered at 1.4 kHz was an effective inhibitor of calling activity. Variation in rate of amplitude modulation of acoustic stimuli had no apparent effect on male calling behavior. These results are discussed in relation to species recognition in bufonids, and acoustic competition between male anurans in general.
Migratory Orientation and Activity of the Meadow Pipit (Anthus Pratensis): a Comparative Observational and Experimental Field Study
Authors: Orth Gerlinde , Helbig Andreas J. , Laske Volker , Wiltschko Wolfgang
Published: April 2008

Meadow pipit migration and orientation was studied by (1) watching visible migration and measuring flight directions with a compass in NW-Germany (1980-1985) and (2) conducting orientation experiments with caged migrants in radial-perch cages (MERKEL & FROMME, 1958). Free-flying pipits migrated SW in autumn and NE in spring in sunny and overcast weather, but on average there was less migration under overcast. In the field migration peaked in the first two morning hours and was almost over by the end of October. Strong migration always corresponded to a minimal scatter of flight directions. In the orientation cages the birds oriented SW in autumn and NNW in spring, but only in sunny weather during the first three morning hours. Activity decreased markedly later in the day (spring), in November compared to September/October and under overcast compared to sunny skies. The more active the birds were, the better was their orientation with respect to the overall mean direction. In general, meaningful orientation in the cages occurred only when migration intensity in the field was maximal. A lack of well-oriented behaviour in the cage is not necessarily caused by an inability to orient, but may be a consequence of low motivation to migrate. A six hour clockshift of experimental birds did not lead to a clear shift of their directional choices, but produced an axial NE-SW orientation in autumn and disorientation is spring. This result does not support the assumption that diurnal migrants orient primarily by means of a sun compass.
The Importance of Vision in Agonistic Communication of the Crayfish Orconectes Rusticus. I: an Analysis of Bout Dynamics
Authors: Bruski Colleen Ann , Dunham D.W.
Published: April 2008

1. The importance of vision for efficient agonistic communication was investigated in the rusty crayfish, Orconectes rusticus, a species active both day and night. Agonistic bout dynamics were analyzed from isosexual pairs of males and females interacting under moderate (350 lux) and dim (11 lux) light levels, and in complete darkness (using infra-red video recording). Under dim light we determined the effect of visual light and dark adaptation on communication. 2. As light diminished, bouts became less frequent, but longer, and the crayfish invested more time and performed more acts when resolving bouts. Thus, communication efficiency was clearly lower in the dark than under moderate light, for both sexes. Males performed more acts than females overall, and were generally more aggressive than females. 3. The frequency of visually-mediated behaviours (e.g. Lunge, Follow) decreased in the absence oflight, while tactile behaviours (e.g. Antenna Tap, Chela Strike, Push) were performed more frequently. Males especially performed more highly aggressive tactile behaviours in the dark. It was shown that some behaviours previously considered to be visually mediated (e.g. Meral Spread) are also tactually or proprioceptively mediated, and some behaviours assumed to be tactually mediated (e.g. antennal movements) are probably also visually mediated. 4. Under dim light, crayfish with light-adapted eyes resolve bouts more efficiently in terms of time and energy investment than do dark-adapted animals. This is consistent with the effects of pigment migrations during dark adaptation in the crayfish superposition compound eye, which enhance visual sensitivity, but decrease acuity. We suggest that dark adaptation diminishes a crayfishes ability to deal with the subtleties of visual communication, but may well enhance its ability to detect predators.
Site-Finding Behaviour of Fasciola Hepatica (Trematoda), a Parasitic Flatworm
Authors: Sukhdeo S.C. , Sukhdeo M.V.K. , Mettrick D.F.
Published: April 2008

Fasciola hepatica is a trematode parasite of the bile duct of herbivores. Site-finding behaviour of this parasite includes a migration from the duodenum through the abdominal cavity to the liver. This study examines the behaviour of the migrating worms at two stages of the life cycle; NEJ - the stage that penetrates the small intestine, and 48HR - the stage that penetrates the liver. Compared to saline controls, crude extracts of duodenal tissue have greater effects on the behaviour of the NEJs while crude extracts of liver tissue have greater effects on the behaviour of 48HRs. Yet, neither NEJs nor 48HRs migrate up gradients of liver extracts or down gradients of duodenal extracts. Stable chemical gradients are difficult to maintain in the motile abdominal cavity and it is suggested that orientation responses play no part in site-finding behaviour. We propose that the major component of site-finding behaviour of F. hepatica is a passive propulsion of the migrating stages through the viscera and along the body wall to the liver.
Vocal Communication in a Neotropical Treefrog, Hyla Ebraccata: Responses of Females To Advertisement and Aggressive Calls
Authors: Bard Kathleen M. , Wells Kentwood D.
Published: April 2008

We investigated the functions of different elements of the complex vocal repertoire of the Panamanian treefrog Hyla ebraccata by testing the responses of females to synthetic advertisement and aggressive calls in two-choice playback experiments. In tests of single-note advertisement calls presented at different rates, females preferred faster calling rates, regardless of the absolute rate of the stimuli. In tests of single-note advertisement and aggressive calls, females preferred advertisement calls. Addition of secondary click notes to aggressive calls made the calls more attractive to females, but multi-note advertisement calls were preferred over multi-note aggressive calls. When females were given a choice of multi-note advertisement calls and single-note calls of the same total duration, they showed no preference. This suggests that multi-note calls are preferred over normal single-note calls because of their longer total duration. When the same experiment was performed with aggressive calls, females showed a strong preference for multi-note calls. This indicates that long aggressive calls, such as those given by males in close-range encounters, may entail some cost to the male in reduced attractiveness to females. Males apparently reduce the costs of aggressive calling by adding click notes to aggressive calls, by giving aggressive calls only when nearby males do so, and by establishing spatial relationships in the chorus before females begin to choose mates.
Beyond the One-Male Group
Authors: Rowell T.E.
Published: April 2008

Social systems are not necessarily equivalent to mating systems. Observation is prerequisite for control of one animal by another. It is not possible without extremely good visibility, which is rare. Nonetheless most social theories assume such control. Neither social position nor copulation guarantee paternity. It is important that biochemical tests provide certainty of paternity in as many studies as possible, so that assumptions about behavioural determinants of reproductive success can be tested. The function of fighting is discussed. Males spend more of their time cooperating than competing, and it is suggested that differences between these may not be so clear. To understand the behaviour of adult males it is necessary to consider behaviour throughout lifetimes, behaviour in all seasons, and behaviour throughout demes. Scepticism towards facile explanations is recommended.
Provisioning Behaviour in a Communal Breeder: an Epigenetic Approach To the Study of Individual Variation in Behaviour
Authors: Jamieson Ian G.
Published: April 2008

This study used an epigenetic approach to examine the development of individual variation in provisioning behaviour in a communally breeding bird, the pukeko. Breeders who are initially 'exposed' to chicks during incubation were the first to brood and provision newly hatched chicks. From the first week after hatching until midway through the provisioning period, there was no significant difference in the percentage of time spent provisioning by breeders and non-breeders suggesting that the maintenance of provisioning is not dependent on increases in hormone levels attained through breeding or incubation, but on stimulations that arise through contact with the chicks. Breeders reduced and eventually stopped provisioning chicks midway through the provisioning period in association with the laying of a second clutch. Social learning, imitation and the 'priming' effect of other behaviours appeared to influence the onset of provisioning in inexperienced or naive juvenile and yearling pukeko. Inexperienced birds initially exhibited a heightened response toward hatchlings which appears to be the result of some sort of novelty effect. Inexperienced yearlings, however, did not provision for as long into the season as experienced non-breeders unless the latter were not present in the group or had stopped provisioning earlier in the season. It is proposed that factors giving rise to and maintaining behavioural asymmetries can best be understood from an epigenetic perspective.
Mate Choice, Mate Guarding and Other Mating Tactics in Golden Hamsters Maintained Under Seminatural Conditions
Authors: Lisk Robert D. , Huck U. William , Gore Andrea C. , Armstrong Michael X.
Published: April 2008

Female hamsters freely interacting with a triad of males which had established a dominance hierarchy mated first and received more ejaculates from the dominant male in 11 of 15 replicates. Continuous observations of the animals on the day preceding receptivity and the day of receptivity suggest that differential mating success of the dominant males is the result of differential behavioral responses displayed prior to onset of receptivity. The females attacked all males, however, the dominant males persisted in following and licking the female at significantly higher frequencies than the subordinate males. The females responded differentially to the dominant males by vaginal marking in response to being licked and also on day 3 of the cycle by placing a higher number of vaginal marks in and around the dominant male's home area. In nine replicates the dominant male and female slept together on day 3. In two other cases the dominant male dug open the female's burrow early on day 4. Dominant males and females became active significantly earlier than subordinate males on day 4. Thus, dominant males enhanced their chances of mating both by being active earlier and by sleeping in proximity to the female. Males cannot prevent the promiscuous female from mating with another male. However, successful males continued to follow and mount the female during the period when she is likely to accept a second male. At this time they also display a high level of attack and chases against the subordinate males plus a high frequency of flank marking in the subordinate's home areas. These behaviors suggest a mate guarding function and are consistent with protection of the male's sperm investment.
The Vocal Repertoire of Adult Tree Shrews (Tupaia Belangeri)
Authors: Binz H. , Zimmermann E.
Published: April 2008

The adult vocal repertoire of T. belangeri consists of 8 distinct sounds which are organized into a graded system. Within the repertoire 4 basic acoustic structures have been distinguished which can be associated with one of the following functional categories: contact, aggression, defence, attention and alarm; Elements repeated continually at short regular intercall intervals showing narrow frequency band spectra occur during courtship and mating in males; Elements of short duration with harmonic spectra, low fundamentals and often low frequency noise components signal alarm which consequently focuses other individuals' attention on the sender or the external stimulus; Elements of irregular repetition rate showing broadband harmonic spectra of highly variable duration and frequency modulation are associated with the vocalizers defensive behavior; Elements with noisy spectra over a wide frequency range parallel aggressive behavior by the vocalizer which is often intensified with visual threat display. The findings of the present study are compared and discussed with data from literature referring to tupaia vocalizations. A comparison with the call system of insectivores and prosimians revealed similarities as well as divergencies. Presence of many similarities regarding the basic structural patterning of contact, aggressive and defensive vocalizations in the three orders indicates a certain conservatism in these sounds. Propagation of alarm calls in tree shrews which lacks in insectivores appears to be a more recent evolutionary development in mammals with the highest degree of elaboration in primates.
The Effects of Cross-Fostering On Selective Song Learning in Estrildid Finches
Authors: Clayton N.S.
Published: April 2008

Male zebra finches, Taeniopygia guttata, which have been cross-fostered to Bengalesc finches, Lonchura striata, learn Bengalese finch song elements with as much accuracy as a male learning from his natural father. However, these elements are sung in phrases which are more nearly zebra finch length and lack the repetitiveness typical of the elements in a Bengalese finch phrase. Male Bengalese finches are also capable of learning song from a zebra finch foster-father. Males vary substantially but they tend to produce fewer, more widely spaced zebra finch elements in a Bengalese finch-length phrase. Both species show selective song learning and it is suggested that phrase length and the absence or presence of repeated elements might act as important cues for species-specific learning. Cross-fostered Bengalese finches seem to learn less than cross-fostered zebra finches: possible reasons for this are discussed.
Vocal Learning of Japanese and Rhesus Monkeys
Authors: Masataka Nobuo , Fujita Kazuo
Published: April 2008

Foraging vocalizations given by Japanese and rhesus momkeys reared by their biological mothers differed from each other in a single parameter. Calls made by a Japanese monkey fostered by a rhesus female were dissimilar to those of conspecifics reared by their biological mothers, but similar to those of rhesus monkeys reared by their biological mothers, and the vocalizations given by rhesus monkeys fostered by Japanese monkey mothers were dissimilar to those of conspecifics reared by their biological mothers, but similar to those of Japanese monkeys reared by their biological mothers. Playback experiments revealed that both Japanese and rhesus monkeys distinguished between the calls of Japanese monkeys reared by their biological mothers and of the cross-fostered rhesus monkeys on one hand, and the vocalizations of rhesus monkeys reared by their biological mothers and of the cross-fostered Japanese monkey on the other hand. Thus, production of species-specific vocalizations was learned by each species, and it was the learned species-difference which the monkeys themselves discriminated.
Mating Behavior of Horseshoe Crabs, Limulus Polyphemus
Authors: Brockmann H. Jane
Published: April 2008

Horseshoe crabs have an explosive breeding system not unlike that of some frogs and toads. They synchronize nesting to only a few hours each day at the time of the spring new and full-moon high tides. Males search for females as they come to the breeding beaches, grasp them with specially modified claws and cling to them, sometimes for weeks. Females lay several clutches of eggs in the sand and the male fertilizes them externally, the only extant arthropod with such a reproductive system. Unattached males cluster around the nesting couple, pushing on and occasionally displacing attached males. An experimental manipulation demonstrated that satellite males are capable of fertilizing eggs which suggests that sperm competition is the primary explanation for the presence of unattached males on the beach. Like other explosively breeding species, male Limulus search for females, often grabbing inappropriate objects, and satellite males compete for access to females. There is little assortative mating and attached and unattached males do not differ in size. In extreme explosively breeding species like Limulus, selection favors those males that are best able to locate and remain attached to females, and there is little opportunity for female choice or male-male competition.
Risk Sensitive Courtship in the Guppy (Poecilia Reticulata)
Authors: Magurran Anne E. , Seghers Benoni H.
Published: April 2008

This study investigated population differences in the courtship behaviour of male guppies, Poecilia reticulata, in the presence and absence of predators. Two Trinidad populations were compared: the Lower Aripo where guppies occur sympatrically with a range of piscivores and the Upper Aripo where levels of fish predation are low. Upper Aripo males displayed risk-reckless courtship behaviour and did not reduce their sigmoid display rate or otherwise modify their courtship behaviour when threatened by two Astyanax bimaculatus. The courtship behaviour of the Lower Aripo males was, by contrast, risk sensitive. These fish performed a lower proportion of sigmoid displays and increased their level of sneaky mating attempts in the presence of predators. Although males from the two populations used both sneaky and conventional courtship behaviours there were individual differences in the use of the reproductive tactics.
Determinants of Male Mating Success in the Temperate Crayfish Orconectes Rusticus: Chela Size and Sperm Competition
Authors: Snedden W. Andy
Published: April 2008

The large chelipeds of male Orconectes rusticus have an adaptive function related to inter-male competition for mates. Large clawed males dominate over smaller clawed, but otherwise physically similar, competitors. Additionally, males with large chela are better able to secure, and more quickly orient, females into the copulatory position. Large clawed males also copulate for longer periods than smaller clawed competitors. The significance of copulation duration is unclear, but is likely related to mate guarding. Sexual selection for increased cheliped size in 0. rusticus has been more intense on males than females. Sperm of the second male to inseminate a dually mated female takes precedence over that of the previous male. The paternity attributable to the second male was determined as approximately 92 % .
The Relationships Among Population Density, Individual Size, Mating Tactics, and Reproductive Success in a Hermaphroditic Fish, Serranus Fasciatus
Authors: Petersen Christopher W.
Published: April 2008

The hermaphroditic reef fish Serranus fasciatus exhibits three types of social systems. The size of a social group is correlated with the local density of conspecifics. At very low densities, isolated pairs of individuals reciprocally spawn with each other, achieving equal current reproductive success. At intermediate group sizes, harems form, with the largest individual typically losing all of its female function and becoming a functional male. In harems, subordinate hermaphrodites obtain little male reproductive success through streaking, an alternative male mating tactic. The lone pure male maintains almost total monopolization of male reproductive success in harems, apparently due to aggressive domination of subordinates. At high group sizes, the ability of the male to monopolize all of the matings in a social group decreases, and some of the larger hermaphrodites obtain some male-role reproductive success by pair spawning with smaller subordinate hermaphrodites while continuing to spawn as females with the male. Mating partners stay relatively constant through time, resulting in a pattern of small 'sub-harems' within harems. These mating tactics are consistent with the hypothesis that dominant individuals increase their current reproductive success in this species by restricting male mating opportunities of conspecifics. Subordinate individuals spawn as males when the dominant is unable to restrict interactions between hermaphrodites that are potential mates, or when they successfully streak. The increased male reproductive success of hermaphrodites in isolated pairs and complex harems compared with hermaphrodites in harems appears to be important in maintaining a hermaphroditic subordinate phenotype in this largely non-reciprocating species.
Co-Operative Breeding in Riflemen (Acanthissitta Chloris) Benefits To Parents, Offspring and Helpers
Authors: Sherley Gregory H.
Published: April 2008

Two types of helpers were observed feeding young of the New Zealand rifleman (Acanthisitta chloris): "regulars" and "casuals". The former contributed significantly to feeding young from only one nest while the latter contributed a trivial amount to young from a number of nests. Regulars were usually unpaired adult males some of which acquired a mate from the brood they helped. While some casuals were unpaired adult males, most were current season offspring helping with their parents' second clutch. The relative contributions of parents and helpers in raising broods were measured to establish the benefits of co-operative breeding to offspring and feeders. Whether or not helpers were present while feeding young, the breeding female's contribution was the same. By contrast, the work load of the breeding male was significantly reduced when helpers were present, but even then he usually contributed more than this mate. That male parents benefited most from helpers feeding young was probably related to their being responsible for most of the feeding in the absence of helpers. A helper's presence did not improve productivity or the male parent's chance of survival. However, female parents of nests with regular helpers survived better than those without. Offspring fed by helpers were not heavier upon fledging nor were their chances of survival improved. The interval between fledging first clutch broods and laying second clutches was the same whether helpers were present or not.