bluuebunny/crossref_metadata_2025_split huggingface dataset:
Partner Attack Inhibition in the Sexually Monomorphic Biparental Cichlid Tilapia Mariae
Authors: Turner George F. , Phiri Lameck M. , Cawthraw Shaun 
Published: April 2008

Abstract
Courtship behaviour was investigated in the sexually monochromatic biparental cichlid, Tilapia mariae, with particular emphasis on the role of submissive behaviour in the process of pair formation. Pair formation successfully occurred when the female had prior residence in the tank, and could occur within a few minutes. Dominant females generally had priority of access to males. In the experiment where pairing occurred, dominant females and males showed practically no overt aggression towards each other. In the confines of a small tank, with no other subordinate conspecifics present, male and female T. mariae did show aggression to one another, but in this case courtship behaviour was entirely absent. Closed-fin postures were employed by both sexes of Tilapia mariae in the early stages of courtship: it is suggested that these served as 'Partner Attack Inhibition' displays. Submissive displays of the kind employed in agonistic encounters are not used in courtship.
Motivational Models of Courtship in Male Threespine Sticklebacks (Gasterosteus Aculeatus)
Authors: Crawford Stephen S. , Colgan Patrick W. 
Published: April 2008

Abstract
The objective of this study was to determine which of the Random, Competition, and Time-sharing models provides the best description of courtship in the male threespine stickleback (Gasterosteus aculeatus). A critical re-evaluation of experiments in this field revealed both theoretical and methodological difficulties. An attempt was made to correct these problems and provide a more quantitative and statistically valid approach to the motivational study of behavioural switching. Eighteen subjects were tested over four stimulus conditions in a modified double-interruption experiment, where they alternated between courtship and nest-related behaviour. The animals were visually presented with one or three females, with or without eggs in the nest. Assessments of motivational 'dominance' were made on the basis of incomplete visits and variation of visit durations. Data on time budgets, and temporal variability and associations were also analyzed. The results provided little support for the Competition model. In 33 of the 36 sessions, the Random model was accepted as a logical default when the various methods of assessment failed to support, or contradicted the Time-sharing model. The remaining assessments of Time-sharing (both female- and nest-dominant) may be considered as artefacts of the assessment procedure. Four possible explanations of these results were discussed with respect to experimental design and motivational theory.
Benefits of Courtship-Feeding for Rifleman (Acanthisitta Chloris) Parents
Authors: Sherley Greg 
Published: April 2008

Abstract1. Courtship-feeding was studied in riflemen (Acanthisitta chloris) in a population at Kaikoura, South Island, New Zealand between 1982 and 1984. The proportion of the food males collected which was donated to his mate was calculated and what proportion of the female's diet this represented. This information revealed that males made a significant early season contribution to parental care. 2. Allied information collected during the pre-lay and egg-laying periods included the time to form eggs, laying interval and clutch size. 3. Courtship-feeding in riflemen involved no ceremony. 4. Copulation attempts did not correspond with bouts courtship-feeding or the peak of courtship-feeding. 5. Pairs spent 91.2% of daylight hours in each other's company, which facilitated coursthip-feeding. 6. Food items delivered in courtship-feeding were significantly larger than those eaten by males or females while foraging for themselves, and larger food items were consistently offered throughout the pre-laying and egg-laying periods. 7. The peak in the volume of food delivered to the female occurred about 3.5 days after the first egg was laid. 8. Overall the male contributed 42% of the food he gathered to the female and this comprised 35% of her total food intake. 9. Females fed themselves enough food to meet maintenance requirements and the extra required for oogenesis was received from the male through courtship-feeding and any reserves stored by the female. 10. Riflemen laid eggs every 48 hours which probably reduced peak energy demands during oogenesis. 11. Courtship-feeding was not associated with second clutches which were significantly smaller than the first clutch laid and reared in a season. 12. Incubation occurred after the last egg was laid but was sometimes delayed. During the delay courtship-feeding continued until incubation started. 13. Courtship-feeding represents a significant early season investment by male riflemen in their offspring which probably allows time to rear two broods thereby improving both parents' productivity. Such early season investment might influence sexual selection towards stable, monogamous pair bonds.
Estimating the Frequency of Constrained Sex Allocation in Field Populations of Hymenoptera
Authors: Hardy I.C.W. , Godfray H.C.J. 
Published: April 2008

Abstract1) Sex ratio theory has assumed that females can produce offspring of both sexes. It has been suggested that some females in haplodiploid populations are only able to produce sons (constrained sex allocation), for example because they are virgin. The presence of such females influences the optimal sex ratio of unconstrained females. The relevance of these ideas to field sex ratios is largely untested. 2) The frequencies of constrained oviposition in three Drosophila parasitoid species are estimated. Constrained, ovipositing females were distinguished by the absence of sperm in the spermatheca. Constrained females were absent or rare in these species. 3) We review data from the literature that allow an estimate of the frequency of constrained females. 4) We conclude that the available evidence suggests that while constrained oviposition is uncommon, there are some species in which constrained females are sufficiently common to select for an observable sex ratio bias by unconstrained females.
The Structure-Oriented Approach in Ethology: Network Models and Sex-Ratio Adjustments in Parasitic Wasps
Authors: Putters Felix , Vonk Marijke 
Published: April 2008

AbstractIt is argued that connectionist models (neural nets, parallel distributed processing systems) have a great potential for changing our perspectives on animal behaviour. The approach is more structure-oriented than the conventional explanation by analogy. The method is used to analyze the principles of organization underlying oviposition decisions of parasitic wasps.
Parasites and Male Ornaments in Free-Ranging and Captive Red Jungle Fowl
Authors: Zuk Marlene , Johnson Kristine , Thornhill Randy , Ligon J. David 
Published: April 2008

Abstract
The morphology and parasite burdens of culled free-ranging red jungle fowl (Gallus gallus) from the San Diego Zoo were compared with those of captive roosters used previously in sexual selection experiments, to determine if results obtained with the captive birds were relevant to more natural situations. Zoo roosters had three helminth gut parasites: Ascaridia galli, tapeworms, and Heterakis. Parasite distribution was generally over-dispersed, with most individuals having none or few worms and some having heavy parasite burdens. These levels were comparable to those artificially induced in test roosters. The appearance of the zoo birds was similar to test roosters as well. Higher parasite burdens in the zoo birds was negatively related to hackle feather redness, comb length, and especially testis volume. The latter finding is discussed in light of information about the relationship between testosterone levels, sexual selection, and the immune system. A new analysis of female choice of uninfected controls versus experimentally infected roosters suggests that females prefer a multivariate array of traits perceived as a continuous, rather than categorical, variable.
Exposure To Predators and Access To Food in Wintering White-Throated Sparrows Zonotrichia Albicollis
Authors: Piper Walter H. 
Published: April 2008

AbstractI studied a free-living population of white-throated sparrows (Zonotrichia albicollis) to determine which, among eleven behavioural, morphological and situational variables, were correlated with the distance from cover at which individuals fed (a presumed index of predation risk) and the amount of time they spent feeding at three observation sites. Time spent feeding was correlated only with dominance, an indication that dominant birds obtained greater access to high quality food. In contrast, an assortment of factors affected distance to cover. Individuals tended to feed far from cover if they were: (1) in large flocks, (2) males, (3) young and (4) subordinate. Distance to cover for the population as a whole increased during cold and cloudy conditions. The failure of dominance alone to determine a bird's distance to cover probably resulted in part from the confusion caused by dominant heterospecifics (e.g. cardinals, Cardinalis cardinalis) and from their apparent tendency to tolerate mainly small white-throated sparrows (which tended to be subordinate) feeding with them. Overall, this study indicates that while dominance clearly allows easy access to food, it is only one of several factors affecting exposure to predators.
The Evolution of Monogamy in Large Primates: a New Hypothesis and Some Crucial Tests
Authors: VAN SCHAIK C.P. , Dunbar R.I.M. 
Published: April 2008

AbstractMonogamy among the large primates is not accompanied by high levels of male care for infants. The selective pressures that have led to its evolution in this case are far from clear. In this paper, we evaluate and test four different hypotheses. Monogamy in these species did not evolve because males are unable to defend access to more than one female. Hence, it must be related to behavioural services provided by the male which substantially increase the female's reproductive output. Existing data argue against the suggestion that these services involve protection against predators or defence of an exclusive feeding area. We propose that the male's service consists primarily in protecting the female against infanticide by other males. Tests that would differentiate this hypothesis unequivocally from other hypotheses are suggested. To the extent that these predictions can be tested with the data currently available, the evidence supports the infanticide hypothesis. We speculate that infanticide avoidance is also responsible for the near-universal occurrence among primates of male-female bonds.
The Agonistic Behaviour of the Three Male Morphotypes of the Freshwater Prawn Macrobrachium Rosenbergii (Crustacea, Palaemonidae)
Authors: Barki A. , Karplus I. , Goren M. 
Published: April 2008

Abstract
The agonistic behaviour of the freshwater prawn, Macrobrachium rosenbergii, was studied in the laboratory. One hour long contests were conducted between prawns matched to size in each of the three sexually mature male morphotypes of this species; Small Males, Orange Clawed males and Blue Clawed males. An agonistic ethogram was established, consisting of 18 different acts. These acts were classified into indicators of dominance or subordinance following the application of cluster analysis. Prawns contests consisted usually of 3 phases: pre-escalated fighting phase, escalated fighting phase and post-escalated fighting phase. Contest phases differed both in the frequency of several acts and in the distribution of acts between the eventual winner and loser. In addition, the relative orientation and elevation of the opponents changed across phases. The inter and intra-individual sequences of acts of the winner and loser during the escalated fight were studied. Despite the similarity found in the behaviour of the two opponents during the escalated fighting, the eventual winner could be predicted by the relative number and duration of nips or by the relative number of times in which Complete and Incomplete-Lifting (two major displays of fight) were performed simultaneously with the snapping of the claws. Differences found among morphotypes pointed out a tendency of shifting from interactions with physical contact towards ritualized interactions without physical contact. This was correlated with the morphotypic developmental pathway and the concomitant increase of claw size.
Social Regulation of Foraging Activities in Polistes Dominulus Christ: a Systemic Approach To Behavioural Organization
Authors: Theraulaz Guy , Gervet Jacques , Tian-Chanski Sophie Semenoff 
Published: April 2008

Abstract
We studied the processes involved in the reorganization of individual behavioural profiles when the foragers were repeatedly removed on a weekly basis. Neither the age nor the hierarchical rank of the individual directly determined the development of its behavioural profile towards that of a forager profile after removal of the former foragers. However, the closeness of the relationship with the brood seems to have been decisive in the adopting of a new task by the individual. We suggest a model for the functioning of the Polistes society and its organizational genesis which involves two levels of regulation acting simultaneously. The dominance hierarchy results in a primary differentiation of behavioural states among the various members of the society. Each individual reacts preferentially according to its own behavioural state to specific categories of environmental stimulations. The type of action which it exerts on the environment both determines its momentary specialization in a specific task and modifies the stimulating situation, which then has lesser effects on the other individuals in the colony. These two processes act in parallel on all the individuals and contribute to maintaining a society with a stable, self-regulated organization. Task organization in the group can therefore be said to be a distributed function which does not require the presence of an individual central organizer.
An Interspecific Comparison of Individual and Species Recognition in the Passerines Turdus Migratorius and Cyanocitta Cristata
Authors: Schimmel Leah , Wasserman Frederick 
Published: April 2008

AbstractRobins (Turdus migratorius) and blue jays (Cyanocitta cristata) were raised in heterospecific and conspecific pairs to observe the impact of early social experience on the later ability to recognize and associate with conspecifics. Birds were also tested to determine if they could distinguish between a 'nestmate' (the bird they were raised with), versus an unfamiliar bird of the nestmate's species. All choices involved combinations of the two species. After thirty days of being raised with another individual (approximately day 10 to day 40 post-hatch), each experimental subject was tested in a weight-sensitive electronic 'choice' apparatus. Blue jays preferred the company of a nestmate over a non-nestmate. Blue jays also chose the nestmate's species when given a choice between two unfamiliar birds, robins chose the alternative to the nestmate's species and did not discriminate between the nestmate and its conspecific.
The Effect of Thermoregulatory Behaviour On the Mating System of the Juan Fernández Fur Seal, Arctocephalus Philippii
Authors: Francis John M. , Boness Daryl J. 
Published: April 2008

Abstract
Recent studies of fur seals and sea lions (Otariids) which are cold water adapted, indicate that social behaviour in hotter climes is constrained by the form and availability of cool substrate provided by the rookery environment. This first study of the behaviour of the Juan Fernández fur seal provides new evidence of this relationship and the extent to which thermoregultory requirements can affect social behaviour in pinnipeds. Females of this species on Alejandro Selkirk Island made daily movements from inland pupping and rest sites to the shoreline and into the water in response to rapid increases in solar radiation to levels exceeding 1.3 cal/cm2/min. Thirty percent of these females floated and groomed offshore in the afternoon in areas protected from the surf by offshore islets and rocky reefs. Males held territories on land either along the shoreline (39%) or in land-locked areas (45%) as is typical of fur seals, or held completely aquatic territories (16%) that encompassed the site where females floated. The average aquatic male, present on territory primarily during the afternoon hours when females floated offshore, achieved as many copulations as did the average land-locked or shoreline male. Land-locked males often abandoned their territories for short periods (45 minutes on average) in response to increasing solar radiation in the afternoon and at a time when female numbers on land were low. The existence of aquatic territoriality as a successful mating strategy has not yet been documented for any other otariid. The occurrence of this behavioural strategy is likely a product of the interaction of thermoregulatory constraints and topographical features which together promote predictable aggregations of females offshore. This study further substantiates that constraints on female aggregation appear to dictate the range and mode of male mating strategies in otariids.
"Coo" Vocalizations in Stumptailed Macaques: a Controlled Functional Analysis
Authors: Bauers K.A. , De Waal Frans B.M. 
Published: April 2008

Abstract
Coo vocalizations have been described in the communication systems of several macaque species. Their use has been suggested to reflect the emitter's "internal state", with regard to motivation for social contact. The idea that the production of Coos reflects a desire for contact has never been critically evaluated; the effectiveness of these signals in facilitating contact between the emitter and others has not been demonstrated. We designed a study to test the function of Coo vocalizations in adult stumptailed macaques (Macaca arctoides), using control measures similar to those first employed in research on reconciliation behavior in macaques (DE WAAL & YOSHIHARA, 1983). We found that the probability of an approach leading to friendly contact was significantly greater following a female's Coo vocalizations than it was during control trials. Analysis of the social context of the focal animal as it emits a Coo (its "initial state"), provides indirect evidence that Coos are "contact calls". We found that stumptails were significantly more likely to be alone than in contact with others when they emitted a Coo. Females were more likely to repeat their Coo vocalizations if they did not achieve friendly contact within 30 s. This result is in line with the view of Coo vocalizations as part of a feed-back loop with affiliative social contact as the goal state. Coos were produced by other adult females at a higher rate and with a shorter latency following the focal female's Coos than they were in control trials. Response vocalizations may affirm, to the "cooing" female, the presence and location of other troop members. On the basis of the non-vocal behavioral changes that these signals predict, Coos may be viewed as social tools, used to influence conspecifics, in addition to whatever their use may reflect regarding an emitter's "internal state". We suggest that the use of Coos to solicit approach may be a convention for the avoidance of aggression.
Levels of Female Choice in the White-Tailed Skimmer Plathemis Lydia (Odonata: Libellulidae)
Authors: Koenig Walter D. 
Published: April 2008

AbstractMale Plathemis lydia defend mating territories along the perimeter of ponds. Females come to ponds for brief periods of time every few days to oviposit. During these visits, females actively discriminate among males, rejecting up to 48.9 % of mating attempts. Males varied significantly in the proportion of attempts successfully leading to copulation. However, males that obtained more matings also experienced more rejections. Extensive analyses based on absolute male size, relative male size, and male size relative to female size yielded only marginally significant evidence of female mate preference based on body mass, wing length, wing loading index, or age; to the extent that any of these characters appeared to influence mating success, they similarly influenced refusal rates. The overall weakness of female mate choice is further suggested by the frequency of females ovipositing without prior matings and by the low frequency with which females remate with the same males. On a population basis, females strongly prefer to oviposit in the middle of the day and at particular parts of the study pond. Thus, females exhibit strong choice at several levels. However, despite the high incidence of active female rejection and high variance in male mating success, mate choice is apparently of minor importance in this population. Female discrimination of males, combined with variance in male mating success, are necessary but not sufficient for the action of sexual selection via mate choice. These findings support the prediction that male-male competition is of primary importance in resource control mating systems in which males are able to control female access to most or all favored oviposition sites. However, it is not clear why females generally fail to discriminate among males, given that they have the opportunity to do so. In general, females appear to have low motivation to mate with males, presumably because multiple mating does not significantly increase their fertility or fecundity. Selection for rapid mating may be significant, both because of predation on females during mating and oviposition and because of the risks for males of losing their territories during mating bouts. This time constraint may be the most important factor limiting female discrimination among males on the basis of consistent characteristics.
Adaptive Pacifistic Behaviour in Subterranean Mole Rats in the Sahara Desert, Contrasting To and Originating From Polymorphic Aggression in Israeli Species
Authors: Nevo Eviatar , Simson Shimon , Heth Giora , Beiles Avigdor 
Published: April 2008

Abstract
Aggression is a polymorphic trait that occurs in subterranean blind mole rats of the Spalax ehrenbergi superspecies in Israel (NEVO et al., 1975, 1986; NEVO, 1991). We found Egyptian mole rats in the isolates to be pacifistic. This supports our evolutionary theory of aggression in Spalax which predicts that aggression should decrease in the desert habitat (NEVO et al., 1986), presumably to minimize overheating, water and energy expenditure. The described behaviour is a pre-requisite for social evolution. We hypothesize that pacifistic behaviour in Spalax isolates in North Africa has been adaptively selected for survival in the harsh Sahara desert ecology.
Interspecific Agonism Between Two Sympatric Species of Ctenomys (Rodentia: Octodontidae) in Captivity
Authors: Vassallo Aldo I. , Busch Cristina 
Published: April 2008

AbstractThe interspecific agonism between two sympatric species of Ctenomys (C. talarum and C. australis) was studied by means of experimental encounters at the laboratory. Aggression took place in relation to occupation and defence of the Resource Cage (RC: food and space) and Home Cage (HC: own or foreign). Opponent's retreat was preceded by fighting behaviors (animal advancing forward; biting) or without apparent aggression. The species that is two times bigger.-C. australis-dominates the other-C. talarum-. However, the results do not demonstrate that C. australis is more aggressive. C. australis entered the RC more often, stayed longer there, less often brought food to the HC, while C. talarum move food to its HC. The ordination and classification of individuals according to their behavior shows species and sex segregation. Species differences supports the interpretation that a bigger individual is avoided more than a smaller one: C. talarum evades C. australis without apparent aggression. A hierarchical interspecific dominance was very distinguishable with our experimental design. We suggest that the habitat segregation pattern observed in the field results, probably, from interspecific interaction.