bluuebunny/crossref_metadata_2025_split huggingface dataset:
Male Courtship Displays, Ornaments and Female Mate Choice in Captive Red Jungle Fowl
Authors: Zuk Marlene , Popma Stacey L. , Johnsen Torgeir S. 
Published: April 2008

Abstract
We studied the role of male courtship behaviour in female mate choice in red jungle fowl (Gallus gallus), the ancestor of domestic chickens. The traits most highly correlated with behavioural displays were those most relied upon by females in making mate choice decisions. These traits (comb length, comb colour, eye colour, and spur length) are highly condition-dependent in jungle fowl. Females chose males that displayed at a greater overall intensity in the period after the female was allowed to interact with the males (post-release), but were indifferent to displays during the period before the female could approach the roosters (pre-release). After accounting for the effect of morphology on mate choice, waltzes were the only display that explained a significant amount of variation in male mating success. Chosen and rejected males had different display rates even when the female was not present. Plasma testosterone level was correlated with pre-release behaviours, but not with post-release behaviours or mating success.
Development of a Selective Response To an Adult Vocalization in Nestling Black-Capped Chickadees
Authors: Clemmons Janine R. 
Published: April 2008

AbstractThere are many studies on how songbirds develop song production, but few on how songbirds develop appropriate responses to conspecific vocalizations. The black-capped chickadee, Parus atricapillus, produces a vocalization, the 'squawk', that stimulates gaping in nestlings during feeding. To determine whether nestlings gape selectively at the squawk, playbacks of several conspecific vocalizations plus a heterospecific vocalization were presented to nestlings within natural nests. A preference for the squawk did not appear until day 2-3 and then steadily increased, until by day 11-13, nestlings gaped only at the squawk. To determine whether there are constraints on which vocalization can develop as the gaping stimulus, newly-hatched nestlings were reinforced with food for gaping either at the squawk or the faint feebee, the two most common adult vocalizations at the nesting site. Regardless of reinforcement, nestlings gaped most frequently at the squawk. In addition, after the first few days posthatch, nestlings became as responsive to a third, unreinforced, heterospecific vocalization as to the squawk. The responsiveness to the heterospecific vocalization coincided with the expanding range of auditory sensitivity that occurs at the same age during passerine development. Thus, while field observations show that nestlings gape mostly to the squawk relative to other parental vocalizations, experimental evidence indicates that there is not an exclusive link between the signal (squawk) and its response (gaping), especially during the first week posthatch when parents use the signal most frequently. Rather, an effectively selective response may be achieved redundantly by a variety of factors. Possible factors that are discussed include matching acoustic structure to nestling perceptual biases and the behavior
The Selfish Crouton
Authors: Fels Daniel , Ap Rhisiart Alun , Vollrath Fritz 
Published: April 2008

Abstract
We studied predator prey interactions on a model system with gulls as predators and bread croutons as prey. The advantage to prey grouping appeared even at low numbers of prey and high predator density. Moreover, individual predators gained by preying upon a group rather than on a solitary prey. Rate of predation was the same for homogeneous (uni-coloured) and heterogeneous (multicoloured) groups of croutons.
Maternal Aggression in Red Swamp Crayfish (Procambarus Clarkii, Girard): the Relation Between Reproductive Status and Outcome of Aggressive Encounters With Male and Female Conspecifics
Authors: Figler Michael H. , Twum Maxwell , Finkelstein James E. , Peeke Harman V.S. 
Published: April 2008

Abstract
A series of experiments investigated intraspecific aggression by maternal (carrying eggs and/or hatched young) and non-maternal female red swamp crayfish (Procambarus clarkii) residents against intrusions by non-maternal female and Form I (reproductively active) male conspecifics. Each resident occupied an aquarium containing a shelter for 24 hours prior to the initial intrusion. The winner of each encounter was determined, as well as the pair member that initiated the aggressive interaction, and the relation between the initiation of aggression and contest outcome. The results showed that: (1) Maternal female residents were winners in 92% of the encounters with male intruders, and initiated aggression in a significantly higher proportion of encounters than the male intruders. (2) Maternal female residents were the winners in 75% of the encounters with non-maternal female intruders. The maternal residents also initiated aggression in a significantly higher proportion of the encounters than the non-maternal intruders. (3) Non-maternal female residents lost 77% of the encounters with non-maternal intruders. Also, the non-maternal intruders initiated aggression in a significantly higher proportion of the encounters than did the non-maternal residents. (4) Non-maternal female residents lost all of their encounters with male intruders. However, there was no significant difference in the proportion of the encounters in which aggression was initiated by residents or intruders. (5) For all experiments combined, maternal residents won a significantly higher proportion of their encounters than did non-maternal residents, regardless of whether the intruders were males or non-maternal females. (6) For the three experiments combined, the initiation of aggression reliably predicted contest outcome (i.e. the initiator of aggression ultimately won). The present results provide the first empirical demonstration, with appropriate non-maternal controls, of maternal aggression in decapod crustaceans. Also, the direct relation between reproductive status and contest outcome in both ovigerous and post-hatch P. clarkii are the first such data reported in crustaceans, in general. Finally, the findings of these experiments bear notable similarities to the results of maternal aggression research in other taxonomic groups.
Female Choice in the Midwife Toads (Alytes Obstetricans and a. Cisternasii)
Authors: Márquez Rafael 
Published: April 2008

AbstractA previous study reported that large males had greater mating success than small males in two species of midwife toads. A behavioural mechanism that would explain such a pattern is sought. Dominant frequency is inversely correlated with male size in Alytes obstetricans and A. cisternasii. In both cases, two-speaker playback tests with synthetic calls show that females have a significant preference for calls with low frequencies. The results shows that female preference may impose directional sexual selection upon a static acoustic character that is correlated with male size. Male Alytes tend their eggs on land, but male size is not correlated with hatching success. Therefore female preference for larger males does not appear to directly increase female fitness.
Reproductive Isolation Among Lateral Plate Phenotypes (Low, Partial, Complete) of the Threespine Stickleback, Gasterosteus Aculeatus, From the White Sea Basin and the Kamchatka Peninsula, Russia
Authors: Ziuganov Valery V. 
Published: April 2008

AbstractReproductive isolation was investigated among sympatric lateral plate morphs of threespine stickleback from the White Sea basin and also among phenotypically similar morphs from the distant Kamchatka River basin (Lake Azabachije). Female choice tests show that gene flow is restricted among the completely plated and low plated morphs at both locations; behavioural isolation between these morphs is complete among Lake Azabachije fish, and nearly so (93% positive assortative mating) among White Sea basin fish. However, the experiments also demonstrate that there are no barriers to reproduction among the Azabachije and White Sea complete morphs, among the Azabachije low and White Sea complete morphs, nor among the Azabachije complete and White Sea low morphs. In addition, there is no evidence of barriers to gene flow among the low and partially plated morphs. Therefore, although gene flow is restricted among the extreme morphs within each locality, nevertheless gene exchange is possible, either directly or secondarily, among all phenotypes. The reproductive isolation between the complete and low morphs from the White Sea basin developed in situ no more than eight generations after the sticklebacks were introduced into an isolated freshwater pond. Therefore behavioural isolation can evolve very rapidly among the lateral plate phenotypes of Gasterosteus aculeatus.
Stability of Social Status in Wild Rats: Age and the Role of Settled Dominance
Authors: Berdoy Manuel , Smith Pete , Macdonald David W. 
Published: April 2008

Abstract
One way of understanding the evolution of social dominance is to establish which factors determine an animal's ability to dominate conspecifics. The dynamics of dominance between 20 adult male wild rats were investigated in a multi-generational, free-breeding colony in a large outdoor enclosure. Dominance relations between the adult males were stable and organised in a near-linear hierarchy. Dyadic interactions not fitting the social hierarchy, as well as challenges by subordinates and overt aggression by dominants were rare (< 5%) and principally occurred between animals of similar social rank. The correlates of social status within the colony show, for the first time in adult small mammals, that despite the significant role of body weight on the probability of winning contests, age was the most reliable indicator of adult dominance, with the higher ranking males being older but not necessarily heavier. Age also explained the outcome of 85% of agonistic encounters between dyads, compared with 65% for weights. The proximate mechanisms of age-related dominance fit better the 'previous outcome' hypothesis than the alternative 'fighting skill' or 'site dominance' hypotheses. The stability of dominance relations and the role of age, which in stable groups is equivalent with time spent in the colony, suggest that rats remain dominant over individuals that they have beaten in the past, long after initial body weight asymmetries have disappeared. The functional significance of the acceptance of subordinate social status is consistent with the fact that dominant individuals generally could not monopolize food resources or mates.
Tool-Set for Termite-Fishing By Chimpanzees in the Ndoki Forest, Congo
Authors: Suzuki Shigeru , Kuroda Suehisa , Nishihara Tomoaki 
Published: April 2008

Abstract
Observations strongly indicate chimpanzees (Pan troglodytes troglodytes) of the Ndoki forest use two types of tools, 'perforating sticks' and 'fishing probes' in combination for termite (Macrotermes muelleri) fishing. Perforating sticks were always made of small, stout branches or young saplings of Thomandersia laurifolia (Acanthaceae), about 10 mm in diameter, with lengths of about 50 cm. Fishing probes were made from the flexible stems of Marantaceae species, and were about five mm in diameter, with lengths of about 50 cm. Approximately 15 cm of one end of the tool was usually shaped into a brush. It is likely that chimpanzees make small holes in the termite mound wall to attain access into the termite nest inside, then they insert the probe into the holes and eat the major and minor soldier termites which bite the brush-like end. Of 214 chimpanzee feces collected, 50% contained termite remains of this species, and this fecal analysis shows that termite-eating behavior occurred all the year around, and did not correspond to the seasonality of rainfall or termite activity on the ground. Chimpanzees in the Ndoki forest seem to be able to obtain termitcs from the deep subterranean nest throughout the year by using their tool-set. Such a tool-set might be responsible for the higher frequency of termite-eating in Ndoki chimpanzees than those of chimpanzees in other sites who fish for termites using only probes. This newly described behavior shows that chimpanzees habitually manipulate a tool on an object which they previously modified with another type of tool.
Differential Costs of Locational and Social Dispersal and Their Consequences for Female Group-Living Primates
Authors: Isbell Lynne A. , Van Vuren Dirk 
Published: April 2008

Abstract
Individuals that disperse may leave familiar conspecifics (social dispersal), a familiar home range (locational dispersal), or both. Social and locational dispersal are not necessarily coincident in group-living animals. Here we differentiate among some potential costs of both social and locational dispersal in group-living mammals, including aggression from strangers and unfamiliarity with new habitats. As an example of the utility of distinguishing between social and locational dispersal, we examine patterns of female transfer in Old and New World anthropoid primates. The results suggest that in Old World primates, female transfer is more likely to be frequent in populations without female aggression between groups. In anthropoid primates, female transfer is more likely to be frequent in populations in which home ranges of groups overlap extensively with those of other groups. Female transfer between groups in Old World, but not New World, primates appears to be more common when females suffer few or no costs of social and locational dispersal. We suggest that when there are few, if any, costs of social and locational dispersal (inferred from moderate to extensive home range overlap and the absence of aggression between groups of females), female transfer in Old World anthropoids will be obligate when groups of females cannot be monopolized by a single male and conditional upon the behavior of individual males when groups of females can be monopolized by a single male. When costs of social and locational dispersal exist (inferred from minimal home range overlap and aggression between groups of females), female transfer will be conditional upon competition with other females in their groups.
The Role of Aggression in Song Tutor Choice in the Zebra Finch: Cause or Effect?
Authors: Jones A.E. , Slater P.J.B. 
Published: April 2008

AbstractYoung male zebra finches (Taeniopygia guttata) normally copy their song from one tutor when given a choice of two. Interaction is known to be a key feature of the learning process and this study examines the way in which one particular type of social behaviour, aggression, may affect tutor choice. Female raised zebra finches were given a choice of two song tutors, which had been pre-selected for differing levels of aggression, during the sensitive phase for song learning. A young bird was significantly more likely to learn from the tutor that was more aggressive to him, as found earlier by Clayton (1987). In addition, behavioural observations suggest that aggression towards the young bird was the cause rather than an effect of tutor choice. There was no significant relationship between the relative level of tutor aggression and the amount of his song copied. Changes in the level of aggression over the tutoring period are also discussed.
Male Mate Choice in a Natural Population of the Parasitic Copepod Lernaeocera Branchialis (Copepoda: Pennellidae)
Authors: Heuch Peter Andreas , Schram Thomas A. 
Published: April 2008

Abstract
Variations in age and sex structure of a natural population of the copepod Lernaeocera branchialis, parasitic on flounder, Platichthys flesus were examined in a 15-month study. Recent laboratory studies and literature on reproductive strategies indicate that male mate choice in this species should depend on the sex ratios of the parasite on its hosts, and on the age and mating status of females. Sex ratios suggested a strong intra-male competition for females. The ratio of chalimus 4 and virgin adult females (preferred stages) to adult males exceeded 1 female: 4 males on 50% of the hosts. In four out of the six sampling periods, more than 50% of hosts harboured more adult males than the total number of females. The males preference for the different female stages was estimated from the number of precopula and copula associations. The data were fitted to a logistic regression model. At most sex ratios, males preferred chalimus 4 and virgin adult females, and discriminated against younger stages. Mated females were about as attractive as the youngest larval stages at female-biased sex ratios, but they were chosen more frequently at strongly male-biased sex ratios. Most adult L. branchialis females had copulated more than once, and some had accommodated at least 5 ejaculates in the their sperm storage organs. The patterns of mate guarding and potential for sperm competition strongly suggest that L. branchialis males take the intrasexual competition into account when choosing mates. On this basis, they minimize guarding time and maximize the possibility of paternity.
Nest Defence By Yellow Warblers: Recognition of a Brood Parasite and an Avian Nest Predator
Authors: Gill Sharon A. , Sealy Spencer G. 
Published: April 2008

AbstractYellow warblers (Dendroica petechia) were exposed to taxidermic mounts of a brood parasite (brown-headed cowbird, Molothrus ater), avian nest predator (common grackle, Quiscalus quiscula) and control (fox sparrow, Passerella iliaca) during their laying and nestling stages to determine whether nest owners distinguish between the threats of brood parasitism and predation. Yellow warblers responded more intensely to the cowbird at the laying stage, performing two unique behaviours (seet calling and nest-protection behaviour) in response to this threat. By contrast, yellow warbler responses to the grackle were greater at the nestling stage, consisting largely of alarm calls (chip, metallic chip and warble calls). The sparrow model infrequently elicited aggressive behaviour from nest owners at either stage. These responses support the hypothesis that yellow warblers discriminate between threats of brood parasitism and nest predation. Yellow warblers may perform specific behaviours to cowbirds because defensive behaviours used against predators may be incompatible with cowbird deterrence. Female nest owners responded more frequently than males at the laying stage, and more intensely than males at both nesting stages. The distance that females and males approached the models and several aggressive behaviours were positively correlated. The greater responsiveness of females may be because they dominate their mates and because females are more experienced with intruders near the nest.
Ontogeny of Action Syntax in Altricial and Precocial Rodents: Grooming Sequences of Rat and Guinea Pig Pups
Authors: Colonnese Matthew T. , Stallman Elizabeth L. , Berridge Kent C. 
Published: April 2008

Abstract
Behavior occurs as coordinated patterns of serial order, with rules of 'action syntax'. Grooming behavior of adult rodents provides several striking examples of action syntax rules. The most stereotyped of these is a 'syntactic chain' pattern, which organizes up to 25 facial strokes and licking movements into a predictable sequence. This pattern previously has been found to be emitted by diverse rodent species from all major suborders: myomorph, sciuromorph, and caviomorph. In this study, we compared the postnatal ontogeny of grooming syntax in two rodent species: rat versus guinea pig. Rats are relatively altricial at birth, whereas guinea pigs are precocial. A day-by-day study of the fine-grain structure of sequential patterns was carried out during the first three weeks after birth, using slow-motion videoanalyses and a choreographic notation system for scoring behavioral grooming sequences. The results showed that substantial action syntax rules exist in guinea pig grooming even on the day of birth. For guinea pigs, postnatal grooming syntax development was limited to minor increments in the strength of the syntactic pattern and in postural control. By contrast, for rat pups, action syntax did not begin to appear until the second postnatal week, and developed gradually into the third week. The development of rodent syntactic patterns in both species appeared to be independent of the maturation of the movements that composed the pattern. Our results indicate that action syntax rules develop as hierarchical entities independent from constituent movements.
Sexual Imprinting in Female Zebra Finches: Changes in Preferences as an Effect of Adult Experience
Authors: Oetting Sabine , Bischof Hans-Joachim 
Published: April 2008

Abstract
It has been shown that sexual imprinting in male zebra finches can be seen as a two stage process with an early acquisition period, where a sexual preference is established, and a consolidation process, where the early acquired preference is linked to sexual behaviour and stabilized. The consolidation process can, by the appropriate experimental design, be delayed until adulthood. In the course of consolidation, the initial preference for the foster species can be altered by exposure to a female of another species. Our results indicate that sexual imprinting in females is also a two stage process. In contrast to males, the consolidation period, at least under the experimental design used in this study, is longer than that obtained for males. It is speculated that the speed of consolidation could be enhanced by additional stimuli influencing female mate choice, as for example breeding facilities.
The Evolution of Hornedness in Female Ruminants
Authors: Roberts S.C. 
Published: April 2008

AbstractFemales of many ruminant species possess horns or hornlike organs, but their precise function remains largely unclear. In this paper, four previous explanations for female hornedness are compared with a new hypothesis, the Female Competition Hypothesis, which suggests that horns initially evolved for reasons of intrasexual competition for resources with con-specifics, the level of competition being correlated with female group size. Each hypothesis is first reviewed and necessary predictions arising from each are generated. In order to test between these hypotheses, the incidence of female hornedness across the ruminants is then examined using a comparative method which takes account of the evolutionary history of each species, in order to control for effects of phylogenetic correlation. Group size and body size are found to be the only variables which predict hornedness successfully; however, when the influence of the other predicting variable is removed, only group size remains as a significant predictor. This analysis is found to support the Female Competition Hypothesis and is shown to be robust both in relation to adjustments in phylogenetic construction (e.g. the position of Aepyceros and Boocerus) and to intraspecific variation in horned condition (e.g. horned and hornless races of Oreotragus).