bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aspects of Necrophoric Behavior in the Red Imported Fire Ant, Solenopsis Invicta
Authors: Howard Dennis F. , Tschinkel Walter R. 
Published: April 2008

AbstractRemoval of dead ants from the nest (necrophoric behavior) is released solely by contact chemical cues in the fire ant, Solenopsis invicta Buren. Exhaustively extracted corpses do not release necrophoric behavior, but the extracts do when applied to filter paper bits. The necrophoric releaser is absent at death but appears rapidly and reaches a plateau within about an hour. The rate of signal appearance is identical in heat and freeze killed workers, implying a non-enzymatic origin. There is no specialized caste or size of worker which carries out necrophoric labor. In the field, in the absence of slope, corpse-bearing workers head outward from the nest on random radii and drop their corpses at unpredictable distances, making refuse piles rare. There is a positive relationship between slope and the presence of refuse piles, and these are located downhill from the mound. When the headings of necrophoric workers were measured in circular arenas in the lab, the only potential orientational cue (tested : landmarks, light, 5°, 10°, 15° slope) which resulted in non-random distribution of headings was slope. The concentration of the headings was a direct function of the slope and seemed to plateau at about 15°. Corpse-bearing ants show stereotyped behavior upon encountering refuse piles and adding their burden to it. Chemical stimuli probably issuing from the feces in the refuse pile bring about the end of necrophoric behavior and maintain the refuse pile. These chemical cues, as also those initiating necrophoric behavior, must be contacted to be effective.
Sexual Selection in the Three-Spined Stickleback: Ii. Nest Raiding During the Courtship Phase
Authors: Li Stacy K. , Owings Donald H. 
Published: April 2008

AbstractThe purpose of this experiment was to test the hypothesis that the disruptive acts (nest raiding), directed by male three-spined sticklebacks, Gasterosteus aculeatus L., toward the eggs and nests of conspecific males evolved as a result of intrasexual selection. We compared the frequency with which a resident male was raided by neighbors when a transparent cylinder containing a male was introduced into his territory, with the frequency of raiding during the presence of a similarly introduced female. On the basis of the intrasexual selection hypothesis, we predicted that raiding should occur more often when the female was present. We also studied the relationship between raiding and the relative dominance status of raided and raiding males. If raiding and dominance conflict are alternative strategies in intrasexual competition, then raiding should have been most intense when raided and raiding males were least discrepant in dominance status. Resident males responded appropriately to introduced fish, i.e., with more courtship and nesting behavior toward females and more aggression toward males. Introduced females were much more effective in eliciting raiding by neighbors than introduced males. The highest status neighbors tended to raid the most. There was some evidence that raiding reduced the raided male's courtship motivation. The outcome of the study is compatible with the hypothesis that nest raiding is adaptive because it increases the relative attractiveness of the raider to females.
The Influence of Size Differential On Agonistic Encounters in the Mantis Shrimp, Gonodactylus Viridis
Authors: Caldwell Roy L. , Dingle Jeri 
Published: April 2008

AbstractThe influence of size on the aggressive behavior of Gonodactylus viridis was examined by matching large animals against others 50, 60, 70, 80, 90, and 100% their size. With size discrepancies of 10% or greater, the larger animals won significantly more of their fights. The smaller participants of a contest avoided more, attacked less, and threatened more than did their larger opponents. When the contestants were evenly matched, attack and avoid values were intermediate, but the animals threatened as often as did the smaller animals. These results are reviewed in light of recent game theory analyses which suggest that threat should be used by the smaller contestant or when the risk of escalation is great compared to the expected pay-off.
The Temporal Pattern of Mosquito Flight Activity
Authors: Peterson Eric L. 
Published: April 2008

Abstract48 Mosquitoes (Culex pipiens fatigans) were isolated in constant darkness and their flight activity monitored with an automatic acoustical recording system. Three basic features were recognized: (I) there was a strong endogenous circadian rhythm with activity in the subjective evening and morning (Fig. 9) ; (2) flights came in bouts with the bouts more closely spaced in the evening activity period (Fig. 10) ; (3) the distributions of flight and interval lengths suggested that the onset and cessation of flight were relatively simple stochastic processes (Figs. 5, 6, 7). A stochastic model, requiring a few simple assumptions, was proposed to accommodate these features. Computer simulation of mosquito activity, based upon the model, generated patterns which looked like the real thing (Fig. 15).
The Functions of Antlers
Authors: Clutton-Brock T.H. 
Published: April 2008

Abstract1. This paper reviews evidence for five functional explanations of the evolution of antlers in male cervids: that they are used as weapons in fights; that they allow individuals to defend themselves against predators; that they act as heat radiators during their period of growth; that they advertise an individual's fighting ability and allow males to assess each other without fighting; and that they increase the chances that a male will be selected as a mate by females. 2. There is extensive evidence that antlers are used in fights between competing males. Contrary to some suggestions in the literature, fights are regular during the breeding season and can be damaging. In species where fighting behaviour has been studied in detail, antlers have proved to be effective weapons of defence and offense, and there is no systematic evidence to support the suggestion that antler-less males (hummels) are more successful in competition for females than antlered stags. 3. Though male deer sometimes use their antlers in defence against predators, the absence of antlers in females of most species suggests that this is not their principal function. Nor does it seem likely that antlers evolved as heat-regulating mechanisms - in some species, they are grown during the winter months and there is no tendency for them to be larger in tropical species than in temperate ones. 4. Despite many suggestions, there is no conclusive evidence that males assess each other by their relative antler size and most measures of antler size and shape are not closely correlated with dominance or fighting ability. Nor is there firm evidence that females selectively mate with large-antlered males. 5. The absence of unequivocal support for the importance of antlers in defence against predators, in heat regulation, in assessment between rivals and in attracting mates leaves open the possibility that, despite their bizarre appearance, antlers evolved as weapons and are retained by selection because of their function in intra-specific combat.
Semen Quality, Female Choice and Multiple Mating in Domestic Sheep: a Test of Trivers' Sexual Competence Hypothesis
Authors: Gibson R.M. , Jewell P.A. 
Published: April 2008

AbstractTRIVERS (1972) proposed that females may choose to mate with males of high sexual competence (the ability to supply sufficient sperm for fertilisation). This hypothesis was tested by allowing ewes in oestrus to choose between four tethered adult rams, two of high and two of low semen quality. Contrary to the hypothesis, ewes did not prefer rams of higher semen quality and, even though frequent mating can depress the fertilising ability of ram semen, the attractiveness of each ram to oestrous ewes was not lowered by frequent ejaculation. Also, in contrast to TRIVERS' suggestion, semen quality and male courtship vigour were not consistently related either between or within individual rams. Ewes mated repeatedly during oestrus, receiving nearly six ejaculates each on average, and over two thirds of ewes mated with more than one ram. Repeated mating, rather than a preference for sexually competent males, might function to ensure fertilisation in female sheep and perhaps in other ruminants.
Time Budgets, Feeding Efficiency and Flock Dynamics in Mixed Species Flocks of Lapwings, Golden Plovers and Gulls
Authors: Barnard C.J. , Thompson D.B.A. , Stephens Hilary 
Published: April 2008

Abstract
1. In mixed species flocks of lapwings and golden plovers, lapwing net rate of energy intake was positively related to the number of conspecifics and the amount of time individuals spent crouching during feeding, but was unaffected by the presence of golden plovers. Plover net rate of energy intake, however, was positively related to crouching tendency, negatively related to the number of lapwings present but unaffected by the number of conspecifics. 2. Golden plovers appeared to join lapwing flocks because they could then crouch more and scan less. The independent negative effect of lapwing number may have been due to feeding interference when there were large numbers of lapwings relative to plovers. 3. When black-headed gulls joined a flock, both lapwings and plovers tended to crouch less and take smaller worms. However, in lapwings these changes appeared to reduce feeding efficiency but plover net rate of energy intake increased as a function of the gull: plover ratio. 4. When gulls were present, the effect of conspecifics on lapwing feeding efficiency disappeared and the presence of plovers had a negative effect. Conversely, in plovers the presence of conspecifics enhanced feeding efficiency and the negative effect of lapwing number disappeared. 5. The arrival of gulls resulted in a decrease in equilibrium lapwing number but no consistent, directional change in plover number. When gulls were present, lapwing number tended to decrease when large numbers of plovers arrived, but increase when small numbers arrived. Increased lapwing number had no significant directional effect on plover number. Changes in lapwing and plover energy intake and species numbers are interpreted in terms of feeding interference and 'dilution' of gull kleptoparasitism. 6. In the absence of gulls, there was no significant directional relationship between increased plover number and lapwing number, but the presence of plovers generally correlated with a reduction in lapwing number. Plover number, however, decreased when large numbers of additional lapwings arrived but increased with small numbers of arrivals. Changes in species energy intake and numbers here are interpreted in terms of feeding interference and time budget changes.
Ecological Constraints On the Social Development of Vervet Monkeys
Authors: Lee P.C. 
Published: April 2008

Abstract1. Immature animals from three social groups of vervet monkeys (Cercopithecus aethiops) living in adjacent territories were observed in Amboseli National Park, Kenya. Measures of diets and food densities suggested that food quality and distribution differed both between the groups and between the dry and wet seasons, such that the dry season was a period of low food quality, and Group A had the lowest food density. 2. Seasonal differences in dietary quality and the time spent feeding produced seasonal differences in the rates of high energy social interactions: play, aggression, and competition. 3. Differences between groups in food availability and quality affected rates of social interactions such that Group A generally had the lowest frequency of interactions. Both between groups and between seasons, low food quality reduced the frequency of interactions and increased the time spent feeding. 4. Play rates were shown to be highly responsive to the energy estimated to be available from the diet during the different seasons such that play was eliminated from the immature social repertoire during the stressful dry season. 5. The time course of weaning also appeared to be influenced by seasonal and inter-group differences in habitat. Few females gave birth in consecutive years, and many suckled their infants into the second year of life. Stressed females weaned infants earlier. It is suggested that prolonged investment is a response to environmental variation and plays an important role in female reproductive strategies. 6. It is suggested that the immatures in these groups maximised the time and energy available for different types of social interactions in a different way in each season and in the different groups. This social flexibility may be viewed as part of an adaptive complex of behaviour during the immature stage of a life history.
Vocal Communication in a Neotropical Treefrog, Hyla Ebraccata: Aggressive Calls
Authors: Wells Kentwood D. , Schwartz Joshua J. 
Published: April 2008

AbstractWe studied the aggressive calls of Hyla ebraccata in Panama by recording natural interactions in the field and by playing recordings of natural and synthetic calls to males. Aggressive calls of this species had higher pulse repetition rates than advertisement calls and often were much longer. Aggressive calls also were much more variable in introductory note duration, pulse rate, rise time, and the number and structure of click notes. Pulse repetition rate was negatively correlated with the duration of the introductory note, as were the number of click notes in the call and the number of pulses in each click. In natural encounters, the duration of introductory notes increased as the distance between interacting males decreased. Males gave aggressive calls in response to playbacks of both advertisement and aggressive calls, but aggressive calls were much more effective in eliciting such responses. The proportion of aggressive calls and the duration of introductory notes generally increased with increasing playback intensity. Playbacks of synthetic calls which varied in pulse repetition rate and rise time showed that a high pulse repetition rate was the most important feature in eliciting aggressive responses from males, but rise time also was important when calls had fast pulse rates. The aggressive calls of this species appear to be a graded signaling system, the first to be documented in amphibians.
Parent-Offspring Conflict in Budgerigars
Authors: Stamps Judy , Clark Anne , Arrowood Pat , Kus Barbara 
Published: April 2008

AbstractDespite widespread theoretical interest in genetic conflict between parents and offspring, there is little empirical evidence that it exists in nature. Theoretical models suggest two outcomes of conflict not predicted by alternate theories: (1) offspring that control the allocation of parental investment might show escalated demand behaviours (e.g., begging) and demand more resources than they could efficiently use and (2) parents might evolve behavioural counterstrategies which prevented offspring from obtaining extra resources, but which were more costly than a "laissez-faire" parental strategy allowing offspring control. These predictions were tested in budgerigars, (Melopsittacus undulatus) in large flight cages at Davis, California. Budgerigar clutches hatch extremely asynchronously, yet all nestlings grew at similar rates and fledged at similar sizes and ages. This independence of hatch order and performance seemed due primarily to the mother budgerigar's allofeeding strategy: females allofed offspring mainly on the basis of size, and only secondarily attended to begging rate. Offspring of a given age and size were treated the same by their mothers regardless of hatch order, and offspring undersized for their age were fed as if they were younger. In contrast, male budgerigars attended to offspring begging rates. Males tended to initiate feeding bouts when offspring begged, and to allofeed vigorous beggers more often. Variance in male allofeeding behaviour allowed comparisons of size-matched families in which females performed nearly all of the allofeeds to nestlings (= female-fed families) with families in which males and females both allofed nestlings (= male-aided families). The parent controlled the allocation of food in female-fed families, while offspring had greater control over food allocation in male-fed families. As was predicted by conflict theory, the female counterstrategy was effective but potentially costly: the food delivery rate of females was only half as fast as males'. Conversely, offspring control resulted in an escalation of beg rate for the same degree of need (as measured by size and growth), and male-aided offspring obtained nearly three times more regurgitations than female-fed nestlings, yet grew at comparable rates and fledged at comparable sizes and ages. Hence, offspring demanded and obtained more food than they could effectively use. Other avian parents also seem to use effective but potentially costly counterstrategies, and other avian offspring may demand more food than they require. Even if initial hatch asynchronies functioned in brood reduction, the parental strategies described here would allow parents to retain control over the timing and conditions for offspring loss.
Splendid Wren Malurus Splendens Response To Cuckoos: an Experimental Test of Social Organization in a Communal Bird
Authors: Payne Robert B. , Payne Laura L. , Rowley Ian 
Published: April 2008

Abstract
A population of cooperatively breeding, group-living splendid wrens was tested with a mounted parasitic cuckoo. At all nests with incubated eggs or nestlings, wrens attacked the cuckoo. The timing and intensity of attacks was independent of the nest day and of the age and breeding experience of the wrens. The breeding female usually spotted and attacked the cuckoo first. Her mate and the nonbreeding helpers responded to her call and mobbed and attacked the cuckoo. Response was no quicker in groups with nonbreeding auxiliaries than in single pairs. Discovery time was independent of the number of birds in a group and depended on the movements of the breeding female. Most wrens fed the young and mobbed the cuckoo. When a wren did not attack, it usually was caring for the young of another breeding female or an earlier brood. Variance in helping behavior was not closely associated with variance in the genetic relationship between helper and the breeding female or the young beneficiaries of mobbing. Use of a common territory, attendance at a nest, feeding the young, and mobbing and hitting a cuckoo were all associated cooperative activities. The main limitation of cooperative behavior in defense against the cuckoo is the same as the observed constraint on care of the young during the prolonged period of parental feeding-a conflict of interest among breeding females for care of their own young.
Determinants of Social Rank in Goose Flocks: Acquisition of Social Rank in Young Geese
Authors: Black Jeffrey M. , Owen Myrfyn 
Published: April 2008

AbstractThe paper describes a study of social rank acquisition in goslings reared from eggs taken from a full-winged flock of barnacle geese (Branta leucopsis) at the Wildfowl Trust, Slimbridge. Eggs were taken from pairs of known history and the adult's aggressiveness was ranked according to their reaction to humans. This rank was shown to be meaningful intraspecifically both by the outcome of encounters between geese and by the fact that no pairs scored as non-aggressive were able to nest in the preferred colony. A group of goslings reared by their own parents and cross-fostered goslings were also examined. 1. Within a rearing group of goslings (sibling-reared broods), the oldest and heaviest birds ranked highest in the first month and males performed better in encounters than females of the same size in the second month. 2. In encounters between unfamiliar goslings from different sibling-broods in the third month of life, the most important determinants of the new rank were body size, weight and sex. Previous experience also influenced rank; previous success yielded continued success. Goslings lost weight during the test; loss was negatively correlated with rank. The performance of goslings reared without adults bore no relationship to their parent's aggressive score. 3. In the semi-captive flock, parents that scored as "aggressive" reared more and larger goslings than non-aggressive pairs. The rank of these in the third month correlated with their size and sex (independent of size). The cross-fostering experiment suggested that there was a genetic as well as an environmental influence on rank acquisition. 4. In encounters between goslings of similar rank from sibling-broods and parent-reared ones, the latter ranked significantly higher. Parent-reared goslings, though less familiar to the experimental regime, gained weight and goslings from sibling-broods lost weight. 5. Once established, rank order remained stable; the few reversals related either to changes in size or to cooperation between goslings in confrontations. 6. Parental quality clearly affects, through learning and heredity, the physical and social development of goslings, and consequently their chances of survival and reproduction. We suggest that these effects are reinforced by brood size; larger families gain better resources in competitive situations. In wild geese, competitive ability is crucial both to survival in winter and to the acquisition of nesting sites and rearing areas for the young.
Feeding-Vigilance Trade-Off in the Teal (Anas Crecca): Effects of Feeding Method and Predation Risk
Authors: Pöysä Hannu 
Published: April 2008

AbstractFeeding and vigilance are conflicting demands in teals (Anas crecca) that use feeding methods where the eyes are beneath the water surface. This trade-off was compared across different beneath-surface feeding methods (head submerged, neck submerged, upending) and between the absence and presence of live predators, ospreys (Pandion haliaetus). A comparison across feeding methods indicated that the proportion of time spent scanning for predators and scanning rate decreased from head submerged to upending. Similarly, within a particular feeding method the level of vigilance decreased as average feeding bout length increased. Teals thus sacrificed vigilance as foraging demands increased. When a predator was present, however, teals increased the proportion of time spent scanning at the expense of feeding time in all feeding methods. This was achieved by lengthening scanning bouts, not by increasing scanning rate. As a consequence, feeding efficiency decreased. Feeding methods differed in terms of predator detection probability. An examination of the role of grouping in increasing predator detection probability indicated, however, that grouping would provide only a marginal benefit to foraging teals in this respect, whatever the feeding method.
Risk and Effectiveness in the Use of Agonistic Displays By American Goldfinches
Authors: Popp James W. 
Published: April 2008

AbstractIn aggressive contests over access to feeders, American goldfinches (Carduelis tristis) appeared to be using displays based on their risk and effectiveness. Display types varied in both their effectiveness and the risk of their use. The effectiveness of using a display was positively related to the risk of using that display. When the value of the resource under dispute was increased individuals used more of the riskier yet more effective displays. Associated with the increased use of the riskier displays was a greater number of encounters ending in fights. Individuals also used each display type with different frequency depending on the relative dominance status of their opponent. Bluffing may have been kept at low levels among the goldfinches by the ease of detecting bluffing, due to individual recognition, and by the costs of being detected.