bluuebunny/crossref_metadata_2025 huggingface dataset:
The Behavior of Aplysia Californica Cooper (Gastropoda; Opisthobranchia): I. Ethogram
Authors: Leonard Janet L. , Lukowiak Ken
Published: April 2008

Aplysia californica has been extremely popular with neurophysiologists interested in understanding the neural basis of behavior. The major drawback to neuroethological work on this species has been the lack of information on its behavior. We present the first ethogram of this species and a model of the physiological organization of drives (motivational systems) in Aplysia. The ethogram of A. californica contains 45 action patterns, most of which involve relatively subtle movements or postures of the head. Some of these action patterns have been studied physiologically and we summarize that information. The action patterns are superimposable and an individual may perform several action paterns simultaneously. A. californica has five distinct "drives" or motivational systems: feeding, escape, reproduction as a male, reproduction as a female and spawning. The sequence of events involved in escape behavior in response to attack by Navanax (a natural predator) or other mechanical stimuli to the rear is described. Each "drive" activates a particular sequence of action patterns, and certain "drives" are superimposable. Aplysia can copulate as a female while copulating as a male, feeding, or laying eggs. On the other hand, escape is incompatible with female sexual behavior. The available physiological evidence suggests that neuropeptides may play an important role in the organization of drives and their interactions. We present a model which combines the available physiological and behavioral data with the classical ethological drive hypothesis to produce a testable model of the physiological organization of motivation in Aplysia.
The Criteria Determining the Selection of Mussels Mytilus Edulis By Oystercatchers Haematopus Ostralegus
Authors: Sutherland William J. , Ens Bruno J.
Published: April 2008

Ventral hammering oystercatchers tend to specialise upon attacking either the right or left valve of mussels. Both in the field and in captivity they initially select medium sized mussels. Selection against small mussels can be understood from the low profitability of small mussels, but large mussels are very profitable. The hammering oystercatchers select thin shelled mussels even though capable of opening ones with thicker shells. Once the preferred prey are depleted, they take thicker and larger mussels. Indirect evidence suggests that within a size class the profitability of thick-shelled mussels is lower. Stabbing birds open larger and thicker mussels than do hammering birds. When feeding on boiled mussels size taken is larger than when feeding on live mussels.
Variation in Mate Guarding Intensity By Male Purple Martins
Authors: Morton Eugene S.
Published: April 2008

The frequency with which individual male purple martins (Hirundinidae: Progne subis) guard their mates during forays to gather nest material varies from 0 to 100%. During such forays, guarding males accompany their mates continuously from the time a female leaves the nest site until she returns to the nest site with nest material. Non-guarding males do not accompany females on these collecting forays. Unguarded females are subject to forced extrapair copulation attempts on almost all of their forays to collect nest material. Because this suggested that non-guarding males may have a lowered assurance of paternity relative to guarding males, I asked if mate guarding frequency is directly related to parental care. However, male parental effort, as assessed by feeding rates, was not related to mate guarding intensity. Mate guarding intensity may vary widely among individual male martins since nest site defense may preclude guarding in some and superiority in sperm competition by means other than exclusive access to females may reduce their chances of being cuckolded.
Complex Organization of the Warbling Song in the European Starling Sturnus Vulgaris
Authors: Adret-Hausberger M. , Jenkins P.F.
Published: April 2008

Male starlings sing two very different categories of song: whistles and warbles. The present study describes the structure and the organization of warbling song in individuals from varied geographical origins. In all cases, warbling is shown to be an extremely complex song in which there is much contrast: very different notes follow each other and are even superimposed. Higher levels of organizations are present: notes are grouped in repeating units, the motifs, each of which is sung in bouts of 1 to 12 repetitions, and finally these bouts show a clear sequential organization. A certain amount of variability occurs at each of these levels: slight variations are seen from one rendition of a given motif to the next; the number of repetitions of each motif varies from one song sequence to another and the sequential organization of bouts seems to be able to vary seasonally. All these characteristics were found in all individuals. Nevertheless, warbling appears to be an essentially individual song. Beyond two or three species-specific motifs, the others in the repertoire are individually characteristic. The beginnings and endings of the songs are clearly defined commencing usually with an individual motif whilst ending with a species-specific motif. We observed marked differences between individuals in repertoire size, extending from about 20 to more than 35 different motifs. This is the only measure of the repertoire that we have been able to define for this continuous song.
Individual Stability, Local Variability and the Cultural Transmission of Song in White-Crowned Sparrows (Zonotrichia Leucophrys Nuttalli)
Authors: Petrinovich Lewis
Published: April 2008

The songs of 306 territorial male white-crowned sparrows were recorded between 1975 and 1983 in two study areas in San Francisco, California. Nestlings were banded and 47 sons whose father's songs had been recorded acquired territories. Some fathers had more than one son who acquired a territory. The songs of 263 territorial neighbours of the sons were also recorded. In addition, there were 32 females for whom both the father's and the mate's songs were available. The songs that were sung on the two study areas differed in a number of qualitative and quantitative aspects. For each area, there was change across years, in qualitative composition of song types, as well as considerable variability in the properties of the songs within dialect areas throughout the course of the study. There were 49 instances in which the song of a territory holder was recorded for more than one year. These individuals exhibited considerable stability of song across years. The song types of sons and fathers and of sons and neighbours were compared; Analysis of these songs indicated that some sons sang the song of the father, some adopted a song similar to that of the neighbours, and some had song with idiosyncratic elements that, in a few cases, remained in the population during succeeding generations. These data provided no support for the hypothesis that sons learned song preferentially from the father: there was no tendency for the quantitative characteristics of the songs of sons and fathers to be more similar than those of sons and neighbours, and when a father had two sons whose song was known, there was little tendency for the three songs to resemble one another. Finally, the songs of a father and his daughter's mate did not tend to resemble one another, indicating that females of this species do not choose as mates males that sing the same song as their father's. These results suggest that variability in transmission of song types may play a role in individual recognition, which in turn might aid a male to acquire a territory.
Maternal Food-Supply Activity and Its Regulation in Coelotes Terrestris (Araneae, Agelenidae)
Authors: Gundermann Jean-Luc , Horel Andre , Krafft Bertrand
Published: April 2008

The funnel-web spider Coelotes terrestris (Agelenidae) displays extended maternal care, especially characterized by a progressive provisioning of the young during a four-eight week gregarious phase. As they grow up, the spiderlings are provided with a increasing amount of prey, which is captured on the web and carried by the mother into the silk tube that represents the nest. This paper is aimed to determine the mechanism that could regulate, throughout the gregarious phase, this food-supply activity. Eleven females were observed, at different times, from one week before egg-laying till one week after the progeny's dispersal. Females' feeding behaviour noticeably changed from the young's emergence onwards. In particular, the prey was less and less handled and the overall time during which the mother kept her prey for herself-Prey Handling Time (PHT)-steadily decreased. Meanwhile, the spiderlings reacted more and more rapidly to the mother's prey catching and carrying, and they stimulated her more and more actively. The mother's prey-supply behaviour was experimentally shown to be modifiable within a short delay. Separating the mother from her brood made her shift her "Prey Handling Time" from a few minutes to more than two hours (i. e. about the level of the pre-emergence PHT). Conversely, reuniting the mother with her brood lead to an equivalent decrease of the PHT. This phenomenon was obtained at four different periods during the gregarious phase. The present study shows that, in this invertebrates species, the maternal provisioning activity is essentially regulated by exogenous factors: i. e. stimulations (that qualitatively and quantitatively variate in the course of time) emanating from the developing progeny.
Cues Associated With Patch-Choice Decisions By Foraging Crab Spiders Misumena Vatia
Authors: Morse Douglass H.
Published: April 2008

I tested the roles of insect prey presence, abundance, and distance in the selection of hunting sites by crab spiders Misumena vatia (Thomisidae) on milkweed inflorescences. Since the inflorescences on a single plant differ in numbers of prey attracted, one can also assess the effect of relative prey abundance on patch choice as overall prey abundance in an area changes. About three-fourths of the spiders chose the inflorescence attracting the most insects on a plant at densities from half to twice the normal prey, and in tests with additional prey presented at close range. Thus they appear to respond to relative prey densities in patch choice, and their accuracy of choice remains constant over a wide range of prey abundance. However, spiders without prey, and ones that had just fed, selected sites randomly. Individuals from all the other experiments left inflorescences, especially high-quality ones, more often as overall prey density increased. This result closely fits a risk-sensitivity model that predicts mobility in choice of hunting site if average prey availability exceeds that required to produce a clutch of eggs.
Diet, Foraging Patterns, and Resource Defense in a Mixed Species Troop of Saguinus Mystax and Saguinus Fuscicollis in Amazonian Peru
Authors: Garber Paul A.
Published: April 2008

In the Amazon Basin of northeastern Peru, moustached (Saguinus mystax) and saddle-back (S. fuscicollis) tamarins form stable mixed species assemblages in which groups of each species feed, forage, rest, travel and cooperatively defend a territory throughout the entire year. Data presented indicate that despite extreme overlap in feeding and ranging behavior, a change in troop size did not have a significant affect on dietary preferences, activity budgets, day range, foraging effort, and the number and length of daily feeding bouts of either resident species. The larger troop, however, was more successful at defending major feeding trees than the smaller troop. Unsuccessful resource defense resulted in a decrease in time spent feeding and foraging, and an increase in the distance traveled to the next major feeding site. It is proposed that within-troop feeding competition is generally not a critical factor in the feeding ecology of this mixed species tamarin troop. Rather, the formation of such a troop enables each resident species to more effectively exploit and defend a set of productive feeding trees.
Food Competition Among Individuals in a Free-Ranging Chimpanzee Community in Kibale Forest, Uganda
Authors: Isabirye-Basuta Gilbert
Published: April 2008

Competition for fruit within chimpanzee foraging parties was investigated by testing the hypotheses that food patch size was a limiting factor to foraging party size and to foraging efficiency while chimpanzees were foraging in Pseudospondias microcarpa trees for fruit. Large food patches (as measured by phenological score or the product of diameter at breast height and phenological score) supported significantly larger parties than did smaller food patches. In addition, foraging efficiency was apparently higher for small parties than for large ones, although the difference was marginally statistically significant. Per-capita feeding time for individuals in small parties was significantly higher than for those in large parties when chimpanzees had access to both Pseudospondias and Uvariopsis congensis fruit trees. Per-capita feeding time was not significantly correlated with food patch size. When Uvariopsis fruit trees became exhausted in mid-August, some chimpanzees apparently avoided severe competition for fruit by leaving the C.C. area, where they had been feeding on both Uvariopsis and Pseudospondias fruit. Social factors did not significantly affect foraging party size nor per-capita feeding time.
Demography and Group Structure in Wedgecapped Capuchin Monkeys, Cebus Olivaceus
Authors: Robinson John G.
Published: April 2008

The extent to which population demography determines the age and sex composition of primate groups was examined using data from a population of wedge-capped capuchin monkeys Cebus olivaceus in central Venezuela. Demographic parameters were derived from censuses of individually recognized, aged, and sexed individuals living in nine groups over a ten year period. Animals were aged by extrapolation from census data. Animals of both sexes were classed as infants during their first year, and juveniles until they reached six years of age. Females reach sexual maturity at this time, while males were classed as subadults until they reached full adult size at age 12. Adulthood lasts at least 30 years in females, at least 24 years in males. Age-sex class specific mortality and fecundity rates generated a life table which indicated that the population was increasing (r = 0.087) between 1977 and 1986. The age and sex composition of the nine groups was described annually. On average, non-adults made up 60% of a group, with this percentage increasing with group size. There were more females than males in all groups in all years. The strong female-biased adult sex ratio (1:4.4) was a consequence of a biased birth sex ratio (1:1.9), higher female than male survivorship especially between the ages of 3 and 7 when males were dispersing, and a pronounced sexual bimaturism. The stable age distribution derived from the life table successfully predicted the observed average distribution of age-sex categories in groups. This suggests that the group structure of Cebus olivaceus groups is not a consequence of intragroup social interactions, but results from demographic parameters.
Reproductive Behaviour of Southern Sea Lions
Authors: Campagna Claudio , Le Boeuf Burney J.
Published: April 2008

The reproductive behaviour of individually marked southern sea lions, Otaria byronia, was studied from 1981 to 1986, at Punta Norte, Peninsula Valdés, Argentina. Males defended territories along the high water mark early in the breeding season but switched to female defence as they were joined by females. Males defended females from neighbours and intruders, and forcefully held pre-oestrous females near them. Males defended territories and females against neighbours and intruders with threat displays and by fighting. Males never strayed far from females. The frequency of aggressive interactions among males was positively correlated with the number of females in oestrus. A mean of 2.8 females was associated with each male in the central breeding area at peak season, with some males being associated with 8-16 females for a few hours. Ninety four percent of the males that held a territory for five or more days copulated. Copulations were not observed away from territories in the central breeding area. Mating success was positively correlated with tenure on territory. The first males to arrive had the longest tenures and achieved the most copulations. Mean tenure on territory was 24 days (range = 15-57 days). The mean number of observed copulations per marked adult male was 3.87 ± 3.31. Variance among breeding males was low; the most successful male achieved only 7% of the copulations observed. Females gave birth a mean of 3.3 days after arrival, copulated once six days later and then went to sea to feed 7.6 days after parturition. Thereafter, females alternated periods of feeding at sea (X = 2.8 days) with periods of nursing their pups (X = 2.3 days). Males sequester pre-oestrous females. This mating strategy leads to differences in behaviour between Otaria and males of other sea lion species. These differences are evident in harem size, time away from females (as manifested by brief and infrequent fighting), the high percentage of males breeding, and the low variance in mating success among breeding males.
Song Tutor Choice in Zebra Finches and Bengalese Finches: the Relative Importance of Visual and Vocal Cues
Authors: Clay-Ton N.S.
Published: April 2008

This paper examined the relative importance of visual and vocal cues for song tutor choice. In the first study zebra finches, Taeniopygia guttata, and Bengalese finches, Lonchura striata, were housed with two song tutors at independence, a zebra finch singing Bengalese finch song and a Bengalese finch singing zebra finch song. All the males tended to learn from the conspecific song tutor, irrespective of whether they had been raised by a pair of conspecifics, the female alone or cross-fostered to a pair of the other species. In the second study zebra finches were housed at independence with two conspecific song tutors, one with a normal song and one which sang Bengalese finch song elements. There was no tendency to learn zebra finch elements which suggests that species-specific elements are not important for song tutor choice in zebra finches. Other vocal differences between the tutors such as length of the song phrase and species-specific call notes might bias learning in favour of the conspecific. Visual differences between the two species, both in appearance and behaviour, seem to be important. Parental cues before independence appear to be relatively uninfluential. However, siblings may be important, both the species and number per clutch: this is a factor which has been overlooked in previous studies of song learning.
Partner Attack Inhibition in the Sexually Monomorphic Biparental Cichlid Tilapia Mariae
Authors: Turner George F. , Phiri Lameck M. , Cawthraw Shaun
Published: April 2008

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

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

1. 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

1) 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

It 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

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

I 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

Monogamy 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

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

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

Robins (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

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

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

Male 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

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

The 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.
Caching Behaviour in the Gray Jay and the Source-Departure Decision for Rate-Maximizing Scatterhoarders
Authors: Waite Thomas A. , Reeve John D.
Published: April 2008

We developed a model that concerns, in part, how long a scatterhoarder should persist in caching food from an ephemeral, locally abundant source ('bonanza') before moving on in search of other sources. The model assumes that an animal scattering food caches for later use behaves in a manner that maximizes the rate at which it stores recoverable (surviving) food in its habitat. It is shown theoretically that under some conditions it is better not to cache all available food but instead to move on in search of other food sources. This 'source-departure decision' for scatterhoarders is analogous to the patch-departure decision for animals that forage among food patches. It is shown that whether, and at what point, a 'moving-on threshold' is reached should depend on the size of the source, the strength of density-dependent cache theft, and the abundance of sources in the habitat. A field experiment was performed to test the qualitative prediction that gray jays, Perisoreus canadensis, should not persist as long in caching food when a day-long opportunity for caching is restricted to a single source (single-source treatment) as when such an opportunity is divided among a series of disjunct sources (multiple-source treatment). In the single-source treatment, jays tended to cache at lower overall rates, transport food items to more distant cache sites, and spend less time caching. These tendencies became more pronounced later in the day. However, although the rate of caching approached zero in the single-source treatment, the jays did not completely cease caching. This apparent violation of the model is attributed to the behaviour of recaching, a facet of gray jay scatterhoarding behaviour that was not built into the model. This retrieval and redistribution of previous caches resulted in the stabilization of the density of caches near the source. In addition, this switch from single- to multiple-load caching trips arguably would make it economical for gray jays to continue to make caching trips from a source beyond the source-departure point predicted by the model. Our theoretical and empirical results begin to show how scatterhoarders may behave in a manner that maximizes the long-term average rate of storage of recoverable food energy throughout their habitat.
The Effects of a Trade-Off Between Foraging and Brood Defense On Parental Behaviour in the Convict Cichlid Fish, Cichlasoma Nigrofasciatum
Authors: Rangeley Robert W. , Godin JEAN-GUY J.
Published: April 2008

Parental convict cichlids, Cichlasoma nigrofasciatum, responded to the presence of a potential brood predator by decreasing net energy gains (food intake decreased and energy expenditure increased) while increasing parental effort (large allocation of time to brood defense). These behaviours are important factors in the life-history trade-off between current and future reproductive investments. The allocation of energy into defense behaviours and elevated activity levels, combined with a voluntary reduction of food consumption, represent an investment in the current brood which could (in nature) reduce future reproduction. Contrary to parental investment theory predictions, consistent increases in parental effort with brood age were not evident.
Variable Leadership in Bar-Headed Geese (Anser Indicus) : an Analysis of Pair and Family Departures
Authors: Lamprecht JÜRG
Published: April 2008

This paper reports quantitative leadership differences in semi-captive bar-headed geese (Anser indicus) at different times of the year, and in different types of groups. Leading is defined here as causing the departure or determining the direction of movement of the whole group. No permanent and exclusive leader of a pair or family group was found, rather relative leading frequencies of male, female and young showed a definite shifting pattern. Females led more often than their mates prior to breeding, and on nest pauses during the incubation period, but less often in summer, autumn and early winter. In families there was no difference between the frequencies of male and female leading. Family females led relatively more often than those of pairs without offspring. This difference was related to the presence, not the number, of young. Goslings led the family about as often as the parents during the rearing period in early summer, less often in autumn, winter and next spring. Such differences and changes are to be expected where competence in particular tasks and dependence on partners vary between group members, and where different situations require different abilities. For the geese, the results can be related to the different options of group members and to the different benefits they derive from leaving (or 'staying put') or following (or waiting for the others) in different situations.