bluuebunny/crossref_metadata_2025 huggingface dataset:
Fertility Advertisement in Birds: a Means of Inciting Male‐male Competition?
Authors: Montgomerie Robert , Thornhill Randy
Published: May 2010

Certain loud calls made by female red junglefowl and Lapland longspurs are given most frequently immediately after egg laying, when a copulation should have the highest probability of fertilizing the next egg to be laid. In these species there is considerable male‐male interaction for access to fertilizable females, and males are attracted to or follow females making these calls. Based on our interpretation of these calls, we develop a general hypothesis to predict the pattern of occurrence of fertility advertisement both within and among bird species. We hypothesize that certain loud calls given by female birds before and during the egg‐laying period are designed to advertise fertility and thereby incite male‐male competition. This hypothesis predicts that calls advertising female fertility should most often occur soon after an egg is laid (i.e. during the period of highest fertility) but may also occur at any time during the female's fertilizable period. Such calls are unlikely to be given by females in strictly monogamous species (especially those with long‐term pair bonds) because in these species each female usually mates with only a single male and extra‐pair copulations are avoided. Although reports of loud female calls associated with copulation are rare in the literature, the 18 examples we found (including junglefowl and longspurs) were predominantly (15/18) in species adopting mating systems other than strict monogamy, and these calls were most commonly and disproportionately reported in multi‐male mating systems. This form of “estrus” in birds may be widespread because few species appear to be strictly monogamous, but it will be difficult to study because the period of high fertility for female birds is so short.
Homing to Hibernating Sites in Helix pomatia Involving Detailed Long‐term Memory
Authors: Lind Hans
Published: May 2010

Hibernation sites and home ranges of marked snails were recorded in the field for several years. Each individual usually returned to the same relatively small hibernating area every year. Shifts between alternative hibernation areas sometimes occurred. Most of the observed non‐returns can be explained by changes in spatial behaviour of the preceding season rather than disorientation. Observations and experiments show the existence of a detailed memory related to topographical features of the hibernating area and lasting for at least three years. The snails seem to orientate towards a goal area which has been memorized at the preparations for hibernation during previous years. Experiments seem to indicate the importance of chemical cues. A probably adaptive potential for very detailed memorizing of topographical cues allows for localization of hibernation areas less than 30 cm in radius, and even accurate returns to previous sites, although no traces of these are left. It seems that the supposedly primitive brain of gastropods like Helix has a capability for complex and long‐term spatial memory similar to that of the vertebrate brain.
Prey Odor Discrimination in the Varanoid Lizards Heloderma suspectum and Varanus exanthematicus
Authors: Cooper William E.
Published: May 2010

Use of chemical senses to detect prey is believed to be an important component of foraging behavior in actively foraging lizards. Ability to detect prey odors and discriminate them from control odors by tongue‐flicking was studied in representatives of two families of lizards having highly forked, elongated, retractile tongues. Responses of gila monsters (Heloderma suspectum) and savannah monitors (Varanus exanthematicus) to deionized water, a control for pungency (cologne), and mouse odor on cotton swabs were studied in experiments using repeated‐measures designs and employing the tongue‐flick attack score (TFAS) as the primary measure of response strength. TFAS differed among treatments for gila monsters and monitors. Both species had greater TFAS to mouse odors than to either of the control stimuli, but responses to cologne were not statistically distinguishable from those to water. Numbers of tongue‐flicks elicited by prey odors were greater than those for control stimuli in V. exanthematicus, but not for H. suspectum. Gila monsters, but not savannah monitors, bit in a significantly greater proportion of tests with prey odors than with control stimuli. Details of responses, including frequency of biting, apparent search behavior in the vicinity of applicators bearing mouse odors, and responses to control stimuli are discussed in relation to the foraging behavior of these two species and their relatives. Evidence from this and other studies suggests that the vomeronasal sense (and perhaps other chemical senses) is an important means of locating and recognizing prey in widely foraging autarchoglossan lizards.
The Role of Visual Cues in Prey Selection in Three‐spined Sticklebacks (Gasterosteus aculeatus)
Authors: Ibrahim A. A. , Huntingford F. A.
Published: May 2010

In order to determine the proximate cues responsible for prey selection by sticklebacks, subjects were given a series of choices between pairs of prey items differing in the visual characteristics that differentiate natural prey species. When only one stimulus‐dimension was varied, the sticklebacks showed significant preference for, in decreasing order for each stimulus dimension, red and pale over dark colour, relatively fast over slow movement, straight and rectangular over globular shape and larger over smaller size. In contrast, the way in which the prey moved did not influence prey choice. When two stimulus‐dimensions were varied simultaneously, colour (if red) was shown to be a more important cue than movement, followed by shape, and then by size. When red colour was replaced by pale colour, a different preference order was found, with movement becoming more important than colour, followed by shape and then by size. These results are discussed in the light of the existing literature of prey selection in fish.
Use of an Inclination Compass during Migratory Orientation by the Bobolink (Dolichonyx oryzivorus)
Authors: Beason Robert C.
Published: May 2010

Adult bobolinks were tested in a planetarium under patterns of nonrotating artificial stars to determine the influence of natural and modified magnetic fields on their migratory orientation. The modified magnetic field was of the same total intensity as the natural field, but the vertical vector was reversed, causing the resulting total vector to point up and north (compared to the natural northern hemisphere vector pointing down and north).

When exposed to the artificial magnetic field, the birds reversed their preferred headings relative to the stellar and geographic references. This response is consistent with the use of an inclination compass. Although 60 % of the individuals reversed their headings the first night, some individuals took up to 5 nights (mean = 2.1 nights).
Spatial and Temporal Resource Use by Feral and Abandoned Dogs
Authors: Daniels Thomas J. , Bekoff Marc
Published: May 2010

We compared spatial and temporal patterns of resource use by feral and abandoned domestic dogs (Canis familiaris) on the Navajo reservation in Arizona and New Mexico. Community dumps provide locally abundant food resources utilized both by feral dogs and dogs abandoned at the dump site. Although population parameters were much the same for feral and abandoned dogs, the use of space varied distinctly and reflected behavioral differences in the way each population responded to the absence of human control, the need to acquire food, and the developmental state of pups. Temporal use of resources by feral dogs varied seasonally with the age of pups in one pack, but not in a second pack. Priority of access to local resources may be influenced by aggressive interactions among dogs at a dump. Barking may serve to warn dogs already present at a dump that competitors have arrived.
Colony Foundation and Nestmate Recognition in the Social Wasp,Belonogaster petiolata
Authors: Keeping Malcolm G.
Published: May 2010

Emergence from hibernation and synchronized nest foundation by foundresses ofB. petiolatain the southern Transvaal, appeared to be stimulated largely by a rise in temperature during early and mid August of each season. Initial foundresses on newly built nests were joined by other foundresses during the first few weeks of the nesting season to form foundress associations. Although females were strongly philopatric and able to discriminate between nestmates (from their natal nests) and non‐nestmates, former nestmates did not reassociate to a significant degree on new nests. Thus, associated foundresses were, on average, not closely related. Rather than facilitating the reassociation of former nestmates, the advantage of philopatric behaviour appears to lie in ensuring that foundresses return to an area of relatively high nesting density, where their chances of being involved in multiple‐foundress groups (irrespective of intra‐colonial relatedness) are high. Non‐philopatric females which nest away from localities of high nesting density have a low probability of being involved in associations, and may therefore have to attempt colony foundation alone, with little or no chance of reproducing successfully.
The Effects of Isolation on the Sensitization and Habituation of Aggression in the Threespine Stickleback (Gasterosteus aculeatus)
Authors: Peeke Harman V. S. , Dark Kathleen A.
Published: May 2010

Our previous research showed that territorial threespine sticklebacks are more aggressive toward a male conspecific placed in their territory if they have been housed adjacent to a gravid female rather than a male or a nongravid female. This study replicated the condition of a territorial male with an adjacently housed male and compared the results with isolated territorial males. This permitted us to contrast explanations for the increased aggression when the neighbor was a gravid female. If the social context determines the level of aggression, then males with no neighbors (isolates) might be less aggressive because there would be no unique reproductive resource to protect nor any neighbor to protect resources from. Alternatively, if aggression is higher in the isolated group it might be because there was no male neighbor to redirect aggression toward. We found that isolated males were more aggressive toward an intruded male stimulus than males with a male neighbor. The study also provided evidence that sensitization produced by the appearance of an intruding male energizes other aggressive behavior, but not those related to feeding, nor does it cause increase in general activation as measured by increased locomotion.
Vigilant Behaviour: Predictability or Randomness? Spectral Analysis of Series of Scan Durations and their Relationship with Inter‐scan Intervals
Authors: Desportes Jean‐Pierre , Metcalfe Neil B. , Brun Bernard , Cezilly Frank
Published: May 2010

While feeding, many animals frequently look up and visually scan their environment. Using spectral analysis of continuous series of scan durations from a purple sandpiper Calidris maritima and Barbary doves Streptopelia risoria, we show that there are sequential non‐random patterns and significant periodicities in all the examined series such that the birds cycled regularly between short and long scans. The cycles are comparable to those for the continuous series of inter‐scan intervals of the same behavioural sequences. We suggest a re‐examination of the functional costs and benefits of instantaneous randomness versus sequential predictability in alternating between feeding and scanning and a revision of the models of the way animals alternate between these behaviour patterns.
Establishment Success of Experimentally Delayed Juvenile Marsh Tits Parus palustris
Authors: Nilsson Jan‐Åke
Published: May 2010

By experimentally manipulating the time when young marsh tits, Parus palustris, could become established, I tested the influence of size, hatching date, social dominance in caged situations, and time of season on establishment success. Individuals that managed to become established were divided into two groups: those that became established in new territories and those that were found in the same territory as the one where they were caught. In no circumstances did size, hatching date or social dominance influence establishment success. The only factor tested that had a significant effect on establishment success, was when the juveniles were released; those that established themselves in new territories had been released earlier than unsuccessful ones. Thus, prior occupancy rather than hatching date per se is the factor determining establishment in new territories. Juveniles that became re‐established in their former territory had been released significantly later than those not becoming re‐established. As the season progresses, increasingly fewer unestablished juveniles are present to fill vacancies. Thus, late‐released juveniles stood a better chance of finding their flock position still vacant compared with juveniles released early, whose previous positions would already have been occupied by other juveniles.
Perceptual Organization in Animal Learning: Cues or Objects?
Authors: Vallortigara Giorgio , Zanforlin Mario , Compostella Silvia
Published: May 2010

Chicks were trained to discriminate between two identical boxes on the basis of their position. Subsequently, the colour of parts of the positive (reinforced) box was changed and chicks were retrained. Results showed that chicks were more or less impaired during retraining depending on the spatial distribution of the changed stimuli. Chicks behaved as if a figure (a disc or a spot of dots) painted on a box was irrelevant to them, whereas they did respond to changes in the colour of a uniformly coloured box or of scattered dots painted on a box. Similar results were obtained in simultaneous discrimination learning tasks involving addition of cues (e.g. colour plus position). Addition of cues facilitated learning using boxes the same colour all over or with painted scattered dots, but not using boxes with a disc or a spot of dots. Furthermore, addition of shape and position information had different outcomes depending on the use of three‐dimensional objects or of painted figures: learning facilitation occurred only using three‐dimensional objects. Results are interpreted in terms of an “object hypothesis”, and the validity and usefulness of traditional terms such as cues is questioned.
Site Tenacity and Dominance in Wintering White‐throated Sparrows Zonotrichia albicollis (Passeriformes: Emberizidae)
Authors: Piper Walter H.
Published: May 2010

Supplemental feeding of a wintering population of 132 white‐throated sparrows was suspended in midwinter to determine characteristics associated with the tendency to remain within previously established home ranges after a drop in food levels. Site‐faithful birds tended to be dominant, to have high levels of subcutaneous fat and to reside in certain regions of the study area. The high site fidelity of dominant sparrows reaffirms the importance of dominance in structuring populations.
The Payoffs to Producing and Scrounging: What Happens when Patches are Divisible?
Authors: Giraldeau Luc‐Alain , Hogan Jerry A. , Clinchy Michael J.
Published: May 2010

Although many group‐foraging models assume that all individuals search for and share their food equally, most documented instances of group foraging exhibit specialized use of producer and scrounger strategies. In addition, many of the studies have focused on groups with strong individual asymmetries exploiting food that is not easily divisible. In the present study we describe individual foraging behavior of relatively nonaggressive flock foragers exploiting divisible clumps of food. Two experiments, one with flocks of spice finches and another with flocks of zebra finches, suggest that divisibility of food patches may have important consequences for social foraging behavior. Neither dominance nor the distribution and quality of food patches affect the relative advantage that producing individuals enjoy over those that scrounge. Specialized producers and scroungers are absent from flocks of both species. Systems where patches are shared may differ fundamentally from those where patches are monopolized by scroungers.
Dominance and Immunity in Chimpanzees (Pan troglodytes)
Authors: Masataka Nobuo , Ishida Takafumi , Suzuki Juri , Matsumura Shuiti , Udono Shunji , Sasaoka Sadanobu
Published: May 2010

The study reported here examined the effect of dominance status on serum immunoglobulin (IgG and IgM) levels in chimpanzees living in five captive colonies. Blood samples were collected from each individual twice, and agonistic and grooming interactions were observed. After initial group observations, members of four of the five groups were caged singly. Thereafter blood samples were again taken. Both IgG and IgM levels of the animals living in groups were significantly negatively correlated with their dominance status in all five groups. The higher‐ranked chimpanzees were likely to show lower levels of IgG and IgM. No such consistent correlation was found between individual Ig levels and frequency of aggressive behaviour or grooming. On transfer to isolated conditions, Ig levels of the chimpanzees did not correlate with their previous dominance status in the groups. Being of high rank is a biological cost for colony‐living chimpanzees with regard to immunity levels.
Male Age, Copulation Duration and Insemination Success inMystacides azurea(Leptoceridae, Trichoptera)
Authors: Petersson Erik
Published: May 2010

Time in copula in the swarming caddis flyMystacides azureaL. (Trichoptera: Leptoceridae) ranged from 0.33 to 44.5 min. It increased with male age (wing wear) and male dry weight, but was independent of male and female size (forewing length), female wing wear and number of eggs in the females. Older males failed to transfer sperm during copulation more frequently than did younger ones. It is suggested that females benefit by interrupting prolonged copulations if sperm is not transferred rapidly, since being in copula might increase the risk of predation. Alternatively, young and old males follow different mating tactics; old males have a lower chance to acquire new mates and they do better by monopolizing a female, once they get one, by prolonging the copulation.
Behavioural Response of Juvenile Bluegill Sunfish to Variation in Predation Risk and Food Level
Authors: Gotceitas Vytenis , Colgan Patrick
Published: May 2010

The behavioural response of juvenile bluegill sunfish (Lepomis macrochirus) to predation risk when selecting between patches of artificial vegetation differing in food and stem density was investigated. Bluegill foraging activity was significantly affected by all three factors. Regardless of patch stem density or risk of predation bluegills preferred patches with the highest prey number. During each trial bluegill foraging activity was clearly divided into a between‐ and within‐patch component. In the presence of a predator bluegills reduced their between‐patch foraging activity by an equivalent amount regardless of patch stem density or food level, apparently showing a risk‐adjusting behavioural response to predation risk. Within patches, however, foraging activity was affected by both food level and patch stem density. When foraging in a patch offering a refuge from predation, the presence of a predator had no effect on bluegill foraging activity within this patch. However, if foraging in a patch with only limited refuge potential, bluegill foraging activity was reduced significantly in the presence of a predator. Further, this reduction was significantly greater if the patch contained a low versus a high food level, indicating a risk‐balancing response to predation with respect to within‐patch foraging activity. Both these responses differ from the risk‐avoidance response to predation demonstrated by juvenile bluegills when selecting among habitats. Therefore, our results demonstrate the flexibility of juvenile bluegill foraging behaviour.
Courtship Display in a Natural Population of Crested Newts, Triturus cristatus
Authors: Hedlund Linda
Published: May 2010

Field observations of courtship displays in a natural population of crested newts, Triturus cristatus, are described. Males were observed both courting females and displaying to other males, and male: male interactions were as frequent as courtships. Many courtships were also interrupted by intruding males, and courtship success was less than 7%. A comparison is made with aquaria studies, which shows that the presence of more individuals in the field, where newts aggregate in leks when breeding, is influencing male behaviour. On the other hand, the different features of the displays observed in the field did not differ to any major extent from behaviour patterns observed in aquaria studies.
Mating in the Scaly Cricket Cycloptiloides canariensis (Orthoptera: Gryllidae: Mogoplistinae)
Authors: Dambach Martin , Beck Ute
Published: May 2010

The process of mating in C. canariensis follows basically the same pattern as in other crickets: adoption of the female‐above‐male position, hooking of the male onto the female's subgenital plate, spermatophore transfer, and separation of the mates. Two crucial modifications can, however, be distinguished: Hooking is not accomplished by means of a sclerotized process from the protruded epiphallus, but with paired hooklets on the paraproct (paraproct processes; sternite 11). The paraproct processes are about 0.4 mm long and covered with bristles, and a group of campaniform sensilla is found in the tip region. The time course of copulation is also modified. Usually, in crickets an already fully formed spermatophore is transferred immediately after mounting, and remains attached for a considerable period. C. canariensis, however, needs about 15 min for spermatophore production, while the couple is already hooked. After transfer the spermatophore remains attached only for an average of 31 s. With both hooklets severed, copulation is unsuccessful. Severance of only one hooklet prolongs the initial hooking phase but shortens the following interval, which suggests that spermatophore production is triggered during a definite interval before hooking, and continues as an autonomous internal process.
Mating System of the Bat Miniopterus minor (Chiroptera: Vespertilionidae) in Kenya, East Africa: a Lek?
Authors: McWilliam Andrew N.
Published: May 2010

The mating system of a migratory bat, Miniopterus minor, was studied in coastal Kenya, East Africa. Although this small (6.3 g) cavernicolous bat is not sexually dimorphic in size, aggregations of males secreted a pungent odour during their annual occupation of a particular erosion hollow, which appeared to function as a lek. This site was monopolized, for some two months before mating, by a group of about 30 adult males that were highly site specific for the cave. These bats were heavier than unsuccessful males and, having occupied the lek one year, were more likely to gain access to it in subsequent years. Potential determinants of the mating system are discussed in relation to observations of other miniopterene bats.
The Mechanism of Queen Regulation of Foraging by Workers in Paper Wasps (Polistes fuscatus, Hymenoptera: Vespidae)
Authors: Gamboa George J. , Wacker Tracy L. , Scope Julie A. , Cornell Thomas J. , Shellman‐Reeve Janet
Published: May 2010

We examined how queens of the primitively eusocial wasp, Polistes fuscatus, stimulate foraging by workers in 10 small, post‐worker‐emergence field colonies. We experimentally increased colony needs, including needs of the brood, by removing a colony's most active foragers (thereby decreasing the colony's foraging rate), and found that the queen significantly increased both her level of activity and rate of aggressive interactions. Most aggressive interactions were directed at dominant workers. Removal of a colony's least active foragers, however, produced no such effect. Our results, together with those of Reeve & Gamboa (1983, 1987), indicate that queens are sensitive to brood needs, and that they behaviorally regulate worker foraging to match brood needs by increasing their level of activity and rate of aggressive interactions.
Homing in the Digger WaspBembix rostrata(Hymenoptera, Sphecidae) in Relation to Sex and Stage1
Authors: Tengö Jan , Schöne Hermann , Chmurzyński Jerzy
Published: May 2010

In the digger waspBembix rostratain males and females of different stages the homing rates and times after release from different distances were investigated.

The homing rate decreased with increase of distance (up to 3000 m).

In females the homing rate increased with progressing stage, from emerging over digging to provisioning.

Numbers for homing times followed the same order: highest in emerging, medium in digging and lowest in provisioning females.

Males showed similar homing rates as digging females. No significant differences between age groups could be found.

The results indicate an effect of sex and stage on the homing capacity. Differences may be traced back to motivation (provisioning females) and lack of experience (emerging females). Landmark orientation, which may include particular search strategies, is a probable orientation mechanism.
Orientation Cage and Release Experiments with Migratory Wheatears (Oenanthe oenanthe) in Scandinavia and Greenland: The Importance of Visual Cues
Authors: Ottosson Ulf , Sandberg Roland , Pettersson Jan
Published: May 2010

Migratory orientation of Scandinavian and Greenland wheatears was recorded during the autumn migration periods of 1988 and 1989. Orientation cage tests were conducted under clear sunset skies, to investigate the importance of different visible sky sections on orientation performance. In addition, wheatears were released under clear starry skies and under total overcast to examine the orientation of free‐flying birds. The following results were obtained:

Wheatears tested with a restricted visible sky section (90° centered around zenith) in orientation cages, showed a mean orientation towards geographic W/geomagnetic NW (Greenland) and towards geographic and magnetic WNW‐NW (Sweden). These mean directions are clearly inconsistent with the expected autumn migration directions, SW‐SSW in Scandinavia and SE in Greenland, as revealed by ringing recoveries for the two populations.

When the birds were allowed a much more extensive view of the sky, almost down to the horizon (above 10° elevation), Scandinavian wheatears chose headings in agreement with ringing data. Greenland birds were not significantly oriented.

Release experiments under clear starry skies resulted in mean vanishing directions in good agreement with ringing data from both sites. Greenland wheatears released under total overcast showed a similar orientation as under clear skies, indicating that a view of the stars may not be of crucial importance for selecting a seasonally accurate migratory direction.

The results suggest that an unobstructed view of the sky, including visual cues low over the horizon, is important, possibly in combination with geomagnetic cues, for the orientation of migratory naive wheatears. Furthermore, the birds showed remarkably similar orientation responses in Greenland and Scandinavia, respectively, indicating that they use basically the same orientation system, despite considerable differences in visual and geomagnetic orientation premises at the two different geographic and magnetic latitudes.
Sulcopolistes atrimandibularis, Social Parasite and Predator of an Alpine Polistes (Hymenoptera, Vespidae)1
Authors: Cervo Rita , Lorenzi Maria Cristina , Turillazzi Stefano
Published: May 2010

Sulcopolistes atrimandibularis Zimmermann is the obligate social parasite of Polistes biglumis bimaculatus Geoffry in Furcroy, a mountain species of paper wasp. Unlike all the other hymenopteran social parasites, the Sulcopolistes female obtains part of the food for her immature brood by plundering other nests of the host species. Parasite females can control more than one host nest: one of them (the nursery nest) she uses solely for reproduction purposes (from which the Sulcopolistes reproductives emerge) and others (supply nests) are used for exploiting the Polistes brood content. It is possible that this behaviour is an adaptation to the extremely short colonial cycle of the host.
Suckling Behavior of the Collared Peccary (Tayassu tajacu)
Authors: Babbitt Kimberly J. , Packard Jane M.
Published: May 2010

Based on Trivers' (1974) theory of parent/offspring conflict, we predicted that weaning would be accelerated under poor dietary conditions in an aseasonally breeding, monomorphic ungulate, the collared peccary (Tayassu tajacu). Suckling behavior was observed in 18 captive litters under a dietary treatment of high or low protein formulated to mimic forage under ecological conditions of normal rainfall vs. drought. Litters on the low protein diet weaned later (mean of 27 weeks) than litters on the high protein diet (mean of 21 weeks). Other indices of cumulative suckling effort (weaning weight, cumulative minutes suckling, cumulative bouts) did not differ between dietary treatments. No differences in suckling effort were found relative to offspring sex or litter size. Milk did not completely compensate for the low protein diet affecting growth of young in the second and third phases of lactation. Some nursers did not conserve bodily resources as would be expected if the benefits of short interbirth intervals outweighed the costs of lactation during unpredictable drought conditions.
Recognition of Predator and Competitor Calls in Nonhuman Primates and Birds: a Preliminary Report
Authors: Hauser Marc D. , Wrangham Richard W.
Published: May 2010

Field playback experiments were conducted in the Kibale Forest, Uganda to determine whether three monkeys (redtail monkeys, blue monkeys, and red colobus monkeys) and one bird (great blue turaco) [1] respond with flight and/or increased vigilance to exemplars of calls given by potential predators (crowned eagle, chimpanzee) and [2] respond differently to food competitors vs. noncompetitors (black‐and‐white casqued hornbill, chimpanzee vs. red colobus). Because the chimpanzee is both a potential predator of all subject species and a food competitor of blue and redtail monkeys and great blue turacos, we also examined whether chimpanzee calls induced responses appropriate to potential predation or competition. Each subject species responded differentially to the calls of potential predators, competitors and noncompetitors. Thus, acoustic cues appeared sufficient for the detection of predators and competitors.
Constraints on Size‐assortative Mating in the Blister Beetle Tegrodera aloga (Coleoptera: Meloidae)
Authors: Brown William D.
Published: May 2010

The mating system of Tegrodera aloga is similar to other blister beetles that have evolved sizeassortative mating in that males pass a cantharidin‐rich spermatophore to their mates and females vary in size and fecundity. Despite this, previous studies found no assortative mating in this beetle. Results of this study suggest that nonassortative mating is not due to absolute constraints on mate choice. Males courted large females more frequently than small females, suggesting that males prefer big mates. Similarly, female choice is suggested by a large‐male mating advantage in the absence of size‐related male‐male competition. In contrast to previous work, my results suggest that assortative mating may occur under certain conditions and may be due to large‐phenotype mating advantages. The question remains, why does assortative mating occur only some of the time? One hypothesis is that assortative mating breaks down when sex ratios become male biased and males no longer discriminate between mates. However, although sex ratios can vary from day to day, assortative mating is not associated with periods when females outnumber males. Rather, the pattern appears to be associated with times of low overall population density. Hypotheses for density‐dependent assortative mating are presented.
Courtship Behaviour and Mating in Two Cow Dung Inhabiting Sphaerocerid Flies (Diptera: Sphaeroceridae)
Authors: Lachmann Anja
Published: May 2010

Adults and larvae of Coproica lugubris and Chaetopodella scutellaris (Diptera: Sphaeroceridae) occur in great numbers on cow droppings. Courtship behaviour and copulation were analyzed and compared. Striking differences were found in the complexity and number of courtship patterns. In contrast to C. lugubris, where males usually mount females without performing any displays, courtship of Ch. scutellaris is rather complex: a male approaches a female and positions himself facing her; he then starts to circle her in a fashion very similar to a male courtship pattern in Drosophila species. Females usually respond to circling with a typical behaviour pattern I called swaying. Its function is discussed. The complex courtship behaviour of Ch. scutellaris is interpreted as a mechanism for female choice. In Ch. scutellaris copulation takes about 60 min longer than in C. lugubris, but the mechanism based upon this obvious difference is not understood. Females of both species can effectively prevent males from copulating.
What is Communicated in the Antipredator Calls of Lemurs: Evidence from Playback Experiments with Ringtailed and Ruffed Lemurs
Authors: Macedonia Joseph M.
Published: May 2010

Two hypotheses of signal specificity in antipredator calls (“referential signalling” and “response urgency”) are discussed in light of prior research on ground squirrels and vervet monkeys. These hypotheses then are examined with data on responses of semi‐captive ringtailed and ruffed lemurs to antipredator call playbacks. Although the responses of ringtailed lemurs support a referential‐signalling interpretation of their antipredator calls, those of ruffed lemurs do not conform well to either hypothesis. Rather, ruffed lemur antipredator calls seem best viewed as “affective” signals that may only reflect underlying emotional/motivational states.
Development of Early Vocalizations and the Chick‐a‐dee Call in the Black‐capped Chickadee, Parus atricapillus
Authors: Clemmons Janine , Howitz James L.
Published: May 2010

The chick‐a‐dee call of the black‐capped chickadee (Parus atricapillus) is composed of discrete elements, or notes, that are combined to form hundreds of different calls. To investigate the development of this complex call, 12 families of color‐marked chickadees were observed and recorded in the wild. Vocalizations were monitored for 18 d in the nest and 14–18 d postfledging. Most vocalizations of nestlings and fledglings were associated with feeding. At hatching, vocalizations consisted of a structurally simple note type that became more complex and variable with age. Around 9–12 d, the development of the call occurred, when single notes became organized into a multiple‐note unit. Notes within the call differentiated into higher frequency, rapidly modulated initial note types and a lower frequency, moderately modulated terminal note type, features also present in adult chick‐a‐dee calls. Several adult‐like calls including chick‐a‐dee calls, fee‐bee songs, and a subsong‐like vocalization developed prior to fledgling dispersal. Based on resemblances of note structure and general call structure, the chick‐a‐dee call appeared to develop from calls of nestlings and fledglings, although not necessarily in a chronologically linear progression. Some features of the chick‐a‐dee call closely resembled features of older nestling and fledgling calls, while other features more closely resembled the sounds of very young nestlings. Vocal development in the chickadee is compared with song and call development in other species, and the possible significance of acoustic resemblances between chick‐a‐dee calls and the food‐associated calls of nestlings and fledglings is discussed.
Seasonal Grouping in Female Moufflons in Relation to Food Availability
Authors: Bon Richard , Gonzalez Georges , Im Sotan , Badia Jacques
Published: May 2010

The social behaviour of ungulates is very often explained by feeding resources. This appears more striking for females since reproduction is very costly in energy terms. We expect female group size to be directly dependent on food availability. Our results on moufflons show that ewe gathering supports this hypothesis during spring, summer and autumn. However, our winter results are contradictory since we observed a stronger tendency of ewes to gather during this season. In the light of recent papers, other ecological or social parameters are discussed to explain this phenomenon.
The Pattern of Helping in the Bell Miner Revisited: A Reply to Jamieson and Craig
Authors: Clarke Michael F.
Published: May 2010

Jamieson & Craig (1987) have argued that the feeding of nestlings by nonparental birds may simply be an unselected consequence of delayed dispersal in cooperatively breeding birds in which philopatric individuals are responding to the stimulus of begging young in their vicinity (see also Jamieson 1986, 1989). Jamieson & Craig (1990) recently criticized my attempt to examine what they describe as this “unselected” hypothesis of Williams (1966) and several selectionist (or adaptive) hypotheses for the current utility of helping behaviour in the bell miner (Manorina melanophrys) (Clarke 1989). In this paper I address specific issues raised by Jamieson & Craig (1990), especially whether the unselected hypothesis is an adequate explanation of the pattern of helping in the bell miner. I will also attempt to highlight the difficulty of formulating specific predictions from the unselected hypothesis and the apparent ease with which it can be modified to accommodate departures from its general predictions.
The Influence of Age, Sex, and Rank on Yawning Behavior in Two Species of Macaques (Macaca fascicularis and M. fuscata)
Authors: Troisi Alfonso , Aureli Filippo , Schino Gabriele , Rinaldi Fabio , de Angelis Nicoletta
Published: May 2010

Yawning behavior was studied in two species of macaques: the long‐tailed macaque (Macaca fascicularis) and the Japanese macaque (M. fuscata). Japanese macaques yawned much more than long‐tailed macaques. Age, sex, and dominance rank exerted different effects on yawning in the two species. In the long‐tailed macaques, sex differences in frequency of yawning emerged only after sexual maturity; yawning rates increased significantly in both males and females as they reached sexual maturity; and, among males, dominance rank was positively correlated with frequency of yawning. Differently, in the Japanese macaques, males, both mature and immature, yawned more than same‐aged females; sexual maturity was associated with an increase in yawning in males only; and male rank did not correlate with the frequency of yawning. Regardless of interspecific differences, the overall results supported only in part the finding that, in Old World monkeys, yawning is largely influenced by plasma concentrations of androgens. There was evidence that social factors were also important in influencing the age‐sex class distribution of yawning.
Temperament in a Fish: A Longitudinal Study of the Development of Individual Differences in Aggression and Social Rank in the Midas Cichlid
Authors: Francis Richard C.
Published: May 2010

A longitudinal design was applied in a study of the development of individual differences in aggression, and their relationship to growth and sexual differentiation in the Midas cichlid, Cichlasoma citrinellum. Weight and standard length measurements, as well as several measures of aggression, were obtained at regular intervals. Size ranks within groups were stable over a period spanning an early juvenile phase through sexual maturity. Two of three aggression rank scores were also stable over this interval, but they did not relate in any direct way to social rank. As juveniles, males showed higher levels of aggression than females, but the reverse was true in adults. This sex‐specific developmental change resulted both from an increase in female aggression at sexual maturity and a decline in male aggression at sexual maturity. Individuals showed distinct and stable behavioral profiles with respect to the combined aggression tests.
Filial Cannibalism in the Biparental Fish Cichlasoma nigrofasciatum (Pisces: Cichlidae) in Response to Early Brood Reductions
Authors: Lavery Robert J. , Keenleyside Miles H. A.
Published: May 2010

Filial cannibalism (eating one's own offspring) may enhance a parent's lifetime reproductive success if the costs associated with this behaviour are outweighed by its benefits. An organism might limit its parental care to relatively high quality offspring and eat the others. Or, an organism capable of repeated breeding in the same season might eat the survivors of a brood that was reduced by predators, and breed again. In this study, we manipulated brood size of convict cichlids by removing 0 % (control), 33 % (ER 33) or 66 % (ER 66) of the eggs spawned. The results show that smaller broods are more likely to be cannibalized by their parent(s) than are larger broods. Furthermore, pairs with reduced broods were preparing to respawn; female gonad weights were significantly higher in the brood‐reduction groups than in the control group. In a second experiment, we show that the behaviour of the parents differed significantly between experimental groups; the ER 66 group performed less parental care than the control group. Moreover, females invested more parental effort than males. The results suggest that filial cannibalism may be a tactic used by parental convict cichlids to enhance their lifetime reproductive success.
Mothers' Egg‐pooling and Aposematic Offspring's Gregariousness: Cui bono?
Authors: Wickler W. , Seibt U.
Published: May 2010

Recently Sillén‐Tullberg & Leimar (1988) modelled a general explanation for the evolution of gregariousness in prey organisms that live exposed, have no means of escape when discovered by a predator, and are small in relation to a potential predator (who thus can sample many prey individuals in one encounter). The model predicts that gregarious prey organisms of that type ought to be distasteful, and that the evolution of gregariousness will be favoured by aposematic coloration facilitating avoidance learning in a predator.

Obviously, any protective power of grouping depends on group size. According to the Sillén‐Tullberg & Leimar model, (1) “members of small groups may have a higher rate of death from predation than solitary individuals, but above a certain minimum group size, group members do better than solitary individuals; … as group size increases above the minimum value, group members suffer fewer and fewer deaths from predation”. They benefit from the “decreased risk of predator attack on any particular individual”, called dilution effect. (2) “The more prey specimens that the predator needs to sample during avoidance learning, the larger an aggregation needs to be in order for gregariousness to be advantageous”. It is further explained that (3) selection resulting from predation favours increase in group size until it “acts like a predator‐satiation mechanism”.
Song Learning in the Anna Hummingbird (Calypte anna)
Authors: Baptista Luis F. , Schuchmann Karl‐L.
Published: May 2010

Songs of wild male Anna hummingbirds (Calypte anna) consist of syllables grouped into phrases. Nearest neighbors tend to share similar syllable types, rhythms and syntax. Songs from different localities contain different syllable types, syntax and repetition indices. A male raised by hand in isolation produced a song consisting of highly variable syllable types of a wide frequency range. The song was simple in structure, and syllables were not grouped into phrases. Three males raised by hand as a group sang songs containing two stereotyped syllable types sung in alternating sequence and without phrase structure. These three males shared syllable types and syntax. The data from our study indicate that despite its relatively simple syrinx the Anna hummingbird learns syllable types, frequency, rhythm and syntax (as do oscines with their more complex syringes) during the song development process.
Maternal Aggression and Litter Size in the Female House Mouse
Authors: Maestripieri Dario , Alleva Enrico
Published: May 2010

It has been commonly argued that, in house mice, female post‐partum fighting against a male intruder functions to protect the offspring from infanticide. The aim of this study was to test the hypothesis that maternal aggression is actually related to pup defence and, specifically, according to parental investment theory, that its intensity should increase with litter size. 60 nulliparous albino female mice were mated and randomly assigned to four experimental groups in which litters were culled at birth to 0, 4, 8, or 12 pups, respectively. On day 8 after delivery all females were tested for maternal aggression against a stranger adult male conspecific (5‐min exposure). No aggression occurred in the group in which all pups had been removed. In the other groups, the proportion of females displaying overt aggression increased with litter size. Several scores of female agonistic behaviour (proportion of females displaying overt aggression, total attacking time, frequency of tail rattling) were significantly higher for the females rearing 8 and 12 pups than for the females rearing 4 pups. Aggressive behaviour of females rearing 12 pups was not significantly higher than that of females rearing 8 pups. No male committed infanticide. These results support the hypothesis that rodent maternal aggression is strictly related to offspring defence and are consistent with the theoretical prediction that, the costs of the defence being equal and the gain in fitness increasing with litter size, the intensity of maternal defence of the young should increase with their number.
The Influence of Oestrus on the Vocalization of Female Gelada Baboons (Theropithecus gelada)
Authors: Moos‐Heilen Regina , Sossinka Roland
Published: May 2010

Female geladas draw the attention of males to their sexual state both by visual and vocal signals. In addition to visual cues our studies demonstrate that gelada females in oestrus use calls which are not uttered normally by anoestrous, pregnant or lactating females. A special call of the female indicates the climax of the copulation. Furthermore, individual recognition and the special meaning of these calls is indicated by playback experiments.