bluuebunny/crossref_metadata_2025 huggingface dataset:
Male Distribution and Mate Searching in the Yellow Dung Fly Scathophaga stercoraria: Comparison between Paired and Unpaired Males
Authors: Otronen Merja
Published: May 2010

Movements by individual males were examined in the yellow dung fly, Scathophaga stercoraria. Males were observed from their arrival until they found a female (paired males) or departed (unpaired males). The focal variables were the male mating status, body size and the number of males and females at the site. Paired males, independent of size, spent more time in the best mate‐searching area (pat and the first up‐wind zone) than unpaired males. Paired males in all size classes moved around and attacked other males more often than unpaired males. Among paired males, males that caught a single female and those that took over a female from another male were very similar in their mate‐searching behaviour. The total time spent searching at the pat was positively related to its resource value as indicated by the number of pairs. Time spent in the best mate‐searching area was negatively related with male numbers. The causes of differences in movements and aggression between paired and unpaired males are discussed. The male distribution around cow pats can be understood only if the differences in movement patterns by paired and unpaired males are taken into account.
Parasitism and Heterozygosity Influence the Secondary Sexual Characters of the European Minnow, Phoxinus phoxinus (L.) (Cyprinidae)
Authors: Müller Gabi , Ward Paul I.
Published: May 2010

The Hamilton & Zuk hypothesis (Hamilton & Zuk 1982) was tested in the European minnow, Phoxinus phoxinus (L.), where the male breeding characters include tubercles, which are horny growths on the skin of the head, and a bright red abdomen. Two trematode parasite species, neither directly transmitted, were present: Diplostomum phoxini in the brains of 100% of the fish and Macrolecithus papilliger in the guts of 44%. The heterozygosity of the fish at 11 loci was determined. The number of M. papilliger was negatively related to redness and positively related to the size of tubercles. The number of D. phoxini was not related to redness but was also positively related to the size of tubercles. Heterozygosity was positively related to redness and negatively related to the size of tubercles. This is the first report of such inverse relationships with heterozygosity. The number of tubercles was positively related to the size and condition of a fish. We suggest that males unable to develop exaggerated characters to display to females, e.g. a bright red abdomen, have the alternative strategy of emphasizing weapons for use in male‐male competition. This effect could explain other reported positive correlations between parasite burden and sexual display.
Influence of the Observer on the Frequency of the ‘Morning‐Dance’ in the Arabian Babbler
Authors: Osztreiher Roni
Published: May 2010

The Arabian babbler, Turdoides squamiceps, displays an unusual behaviour, the ‘morning‐dance’. This article examines the influence of the presence and behaviour of an observer on the dance frequency. The results are the summary of more than 3 yr of study by 12 observers, who performed 1335 observations and witnessed 286 dances that took place among 15 groups of babblers. Different experiments were carried out on 148 additional mornings.

Different observers witnessed different dance frequencies. Dance frequency witnessed by an observer decreased with observer's experience. Observers watching groups of babblers on single days witnessed more dances than those who watched the same groups for several consecutive days. Dance frequency was higher on the first day of a series of observations than on the following days in the same series. If a group of babblers remained unobserved for one day, the frequency of dancing increased. An evening observation considerably decreased the frequency of dancing the following morning. Feeding experiments did not elevate dance frequency. Experimental disturbance at the roost before dawn increased dance frequency while permanent disturbance and frightening experiments did not. Change in the observer's presence and behaviour caused the babblers to react by dancing. The hypothesis that the observer's presence and behaviour influences different group members differently, and therefore alters the relationships among them, is offered to explain the results that observers can affect the dance frequency.
Patterns of Vocalization Use by Female Red‐winged Blackbirds (Aves: Emberizidae, Icterinae): Variation and Context
Authors: Armstrong Timothy A.
Published: May 2010

Variation within communication systems can be examined at several levels: variation among individual notes, variation in the arrangement of notes, and variation in delivery. Here, variation in the arrangement and delivery of notes used in female red‐winged‐blackbird vocalizations is described, and this variation is examined for correlations with the context in which the vocalizations were given. Within a vocalization, notes were normally arranged in a series of similar notes. Of the 75 different note arrangements recorded from the population, 12 arrangements accounted for 84 % of vocalizations. Provisional results indicate that the arrangement of notes was influence by the following contexts: 1. The stage of the breeding season; 2. The individual female; 3. The breeding status of the female; 4. Certain female behaviour patterns; 5. Other red‐winged‐blackbird vocalizations; and 6. The presence or absence of a female's mate in the territory. Variation in delivery was measured by the number of notes within a vocalization; delivery was influenced by the stage of the breeding season, the individual female, and the breeding status of a female. Most note arrangements were used in a wide variety of contexts and did not appear to be functionally distinct.
Homing in Red Squirrels (Tamiasciurus hudsonicus): the Importance of Going Straight
Authors: Bovet Jacques
Published: May 2010

This paper examines the orientation of red squirrels (Tamiasciurus hudsonicus) released at a distance from their home range, after having been displaced along a standardized detour with full view of the landscape. Their initial choice of homing directions was totally random, in contrast to the good homeward orientation of squirrels in a previous study that were displaced in identical conditions except that the displacement routes were straight. No other aspect of homing behavior was affected by the difference in treatment. This finding suggests that the relative straightness of outward journeys in spontaneous excursions by squirrels and a variety of other mammals is important for correct return orientation.
Hiding Behaviour of Longtailed Macaques (Macaca fascicularis). I. Theoretical Background and Data on Mating
Authors: Gygax Lorenz
Published: May 2010

During an observational study of captive longtailed macaques (Macaca fascicularis), the ability to hide was analysed within the social context of mating. Low‐ and middle‐ranking males and their female partners chose places for mating where they were partly or entirely concealed more often than easily visible places. These places were not the preferred places of either sex in general, although it was also observed that lower‐ranking animals of both sexes lead a more inconspicuous life than high‐ranking animals. The probable mechanisms of this phenomenon are discussed: trial‐and‐error learning or a simple rule of thumb seem to be the appropriate explanations since the choice between different structures of hiding places is not as sharply defined as would be expected if ‘perspective taking’ were the mechanism.
Bumblebees Do Not Respond to Variance in Nectar Concentration
Authors: Waddington Keith D.
Published: May 2010

Worker bumblebees (Bombus fervidus) were given repeated binary choices between two colors of artificial flowers with the same associated mean nectar concentration (X̄ = 20%), but with different variances in nectar concentration. Flowers of one color, yellow or blue, rewarded a bee with 1 μl of 20% sucrose solution (low‐variance flower type) on each visit (p = 1) and flowers of the other color rewarded a bee on each visit with 1 μl of either 10% or 30% sucrose (p = 0.5; high‐variance flower type). Of the 10 bees tested, nine showed no preference for either the high‐ or low‐variance flowers (indifferent or risk‐insensitive). This result is similar to honeybee responses to variation in nectar concentration, despite differences in foraging ecology between bumblebees and honeybees. Flower‐choice behaviour in the presence of variance in nectar concentration is a response to the expected concentration of the alternative flower types. Possible mechanisms of risk‐sensitive foraging behaviour in bees are discussed.
Trade‐off between Visual Detectability and Nutrient Content in the Patch Choice of the Pyrenean Salamander Euproctus asper
Authors: Uiblein Franz , Engelke Silke , Parzefall Jakob
Published: May 2010

According to predictions based on recent foraging theory, animals encountering two or more patches that contain the same prey type at different densities should choose the higher density patch. If detectability varies among patches, foragers should trade off search costs with nutritional benefits to be gained from either patch type. To test this latter prediction, young Pyrenean salamanders (Euproctus asper) were confronted with both a conspicuous and a concealed patch consisting of living chironomid larvae enclosed in two glass micro‐aquaria. During four experimental treatments, the prey density in the two patches was altered. The salamanders showed a clear preference for the conspicuous patch in three treatments, but switched to an increased choice of the concealed patch in the fourth treatment when only a single chironomid was presented in the conspicuous patch compared to 19 chironomids in the concealed patch. However, during treatments with high prey densities in the concealed patch, E. asper choice performance was probably influenced by a dominance of visual over extra‐optical perception. During choice of the concealed patch, E. asper snapped at lower frequencies than during choice of the conspicuous patch, indicating a change in the foraging style related to prey encountered in darkness. These results provide novel insights into the behavioural tradeoffs met by foragers during diet choice and provide a basis for future modelling of choice scenarios among alternative habitat types.
Graded Aggressive Calls in the African Painted Reed Frog Hyperolius marmoratus (Hyperoliidae)
Authors: Grafe T. Ulmar
Published: May 2010

The African painted reed frog, Hyperolius marmoratus, has a potentially complex communication system. Advertisement calls and aggressive calls, although distinct from each other, are in fact two ends of a continuum of graded calls. Playback experiments using standard advertisement calls showed that males increased the proportion of aggressive calls as the stimulus intensity was increased. In addition, three characteristics of the aggressive calls changed in response to higher playback levels. Males increased the number of pulses/call, increased call duration, and decreased dominant frequency. Aggressive calling occurred primarily during the early hours of the night, with considerable overlap with times when females were searching for mates in the chorus. Females tested in two‐choice arena trials discriminated against aggressive calls in favor of advertisement calls. It is suggested that aggressive calls reduce a male's ability to attract a female and that a graded signalling system may enable males to escalate agonistic encounters with other males without rendering calls completely unattractive to females.
Components of Visual Prey Recognition by the Mexican Aquatic Garter Snake Thamnophis melanogaster
Authors: Garcia Constantino Macias , Drummond Hugh
Published: May 2010

Garter snakes (genus Thamnophis) rely mainly on chemical cues to recognize prey, but in some of the more aquatic species visual stimuli may suffice to elicit predatory attacks. However, the only visual components known to be involved in the visual release of attacks are movement and contrast with background. We explored other visual components by presenting visual models varying only in size, shape, or path of movement to an aquatically specialized species, Thamnophis melanogaster. Snakes responded preferentially to models consistent in size with natural prey, to models having non‐elongate shapes regardless of type of contour (rounded or angular), and to those following paths with vertical, rather than only horizontal, components.
Mate Choice in Captive American Kestrels,Falco sparverius, Parasitized by a Nematode,Trichinella pseudospiralis
Authors: Henderson Derin , Bird David M. , Rau Manfred E. , Negro Juan J.
Published: May 2010

The American kestrel(Falco sparverius) — Trichinella pseudospiralishost‐parasite association was used as a laboratory model to study the effect of a nematode infection on (1) mate choice of female kestrels and (2) competitive abilities of male kestrels during the breeding season. Females were given the opportunity to choose between infected and uninfected males. There was no significant difference in the proportion of females that chose uninfected (n = 18) over infected (n = 16) males. Eight of 11 competitions between infected and uninfected males exposed to a caged female and a nest box were dominated by uninfected males. Female kestrels seemed to base their choices on the intensity of display effort by the males; the experimental level of infection did not affect male courtship behaviour. AlthoughT. pseudospiralisis known to debilitate American kestrels, parasitized males in mate‐choice tests may have diverted energy from less important functions to court the females.
Territory Defence in Black Redstarts, Phoenicurus ochruros: Effects of Intruder and Owner Age?
Authors: Landmann Armin , Kollinsky Christian
Published: May 2010

European black redstarts, Phoenicurus ochruros, vigorously defend all‐purpose territories and exhibit delayed plumage maturation, most subadult males looking exactly female‐like in their first breeding season. We tested the hypotheses that such dull subadult male plumages are beneficial in order to reduce aggression of adult males either by deception or by honest signalling of subordinance status, and that, in turn, conspicuous (adult) plumage colorations are able to intimidate contenders because they act as a signal of fighting ability and aggressive motivation. Adult and dull yearling black redstart territory owners were confronted with intruders mimicked by stuffed mounts of either a conspicuous adult or a dull subadult male. Our results do not support the hypotheses tested: dull plumages of young intruders did not reduce aggression from adult territory owners and aggressiveness towards intruders was significantly higher in yearling territory owners as compared with adult owners. Conspicuous intruders did not deter dull territory owners and we found no indications that conspicuous male coloration is a signal of fighting ability or aggressive motivation in this species. Instead, the amount of aggressive response to intruders showed considerable individual variance within age classes regardless of the plumage of the intruder and the status of the owner.
The Social Organization of the Cape Ground Squirrel (Xerus inauris; Rodentia: Sciuridae)
Authors: Waterman Jane M.
Published: May 2010

The Cape ground squirrel (Xerus inauris) of southern Africa is a tropical species that does not hibernate. Field observations using scan and all‐occurrence sampling revealed that this species was highly social. Female Cape ground squirrels formed social units of related females and their subadult young, as is typical for other ground squirrels. Female social groups were usually composed of 2–3 adult females and 2–3 subadults of either sex. Members of these female social groups shared sleeping burrows and feeding ranges. Female social groups did not cooperatively defend their feeding ranges from adjacent groups in other burrow clusters. Interactions within female social groups were highly amicable, and no dominance hierarchy was evident. Males in this species also lived in groups. These all‐male bands of up to 19 individuals lived almost independently from female groups. The entire male band shared one home range, although ephemeral sub‐bands were formed daily. The composition and size of these sub‐bands changed daily. Interactions among males, which were largely amicable, included allogrooming and sleeping together. Analysis of interactions within the band indicated a stable, linear, dominance hierarchy among males. Dispersal in this species appeared to be male biased as is typical of other ground‐dwelling squirrels, with males dispersing at reproductive maturity. Males joining male bands were thus dispersers and were not likely to be closely related. Sociality in the Cape ground squirrel may be summarized as highly social female kin clusters and associated social non‐kin bands of males.
Do Fleas, and/or Old Nest Material, Influence Nest‐site preference in Hole‐nesting Passerines?
Authors: Olsson Karin , Allander Klas
Published: May 2010

This study examined nest‐site choice in a migratory population of pied flycatchers (Ficedula hypoleuca) and sympatric populations of three resident tit species (Parus major, P. caeruleus and P. palustris) in central Sweden. All four species are secondary‐cavity nesters which naturally breed in pre‐formed tree cavities but readily use artificial nest boxes. We asked whether flycatchers and tits discriminate between nest boxes that: 1. Are ‘empty’; 2. Contain old nests without ectoparasites (fleas Ceratophyllus sp.); or 3. Contain old nests with ectoparasites. We found that pied flycatchers preferred nest boxes containing old nests, regardless of whether these nests held parasites. In contrast, tits did not discriminate between the three types of boxes. Tits may pay a cost for their lack of choosiness: after the breeding season, tit nests contained more fleas than flycatcher nests. Nevertheless, parasites did not affect the choice of a nest site in any of the species studied. We suggest that the migratory flycatchers are in a hurry to start breeding upon arrival and use the presence of an old nest as a shortcut cue to assess nest‐site quality. Also, they may save valuable time by copying the choice of previous breeders. Non‐migratory tits may have more time to inspect nest sites, but do not seem to use the same cues in nest‐site selection as the pied flycatcher.
Unattractive Males Guard Their Mates More Closely: an Experiment with Bluethroats (Aves, Turdidae: Luscinia s. svecica)
Authors: Johnsen Arild , Lifjeld Jan T.
Published: May 2010

Mate guarding by close following is assumed to function as a paternity guard in pair‐bonding birds. Although this behaviour has been described for many species, little is yet known about the variation in mate‐guarding intensity between males in a population and the reason for such variation. In this study, we wanted to examine how mate‐guarding intensity relates to the sexual attractiveness of the male. Male bluethroats, Luscinia s. svecica, have a bright throat patch, an ornament extensively displayed during courtship. Two experiments are reported. In the first, we show that males which had their throat patch blackened (with Nyanzol D) before pairing had a lower pairing success than control males. We conclude that the blackening of the throat patch reduced male attractiveness. In the second experiment, a group of males were blackened after pairing. These males guarded their mates more closely than did control males, and spent less effort advertising for secondary mates. Thus, we conclude that a male's mate‐guarding intensity is flexible and negatively related to his sexual attractiveness. The mechanisms by which a male can assess the likelihood of becoming cuckolded are discussed.
Ontogeny of Flehmen in Sable Antelope, Hippotragus niger
Authors: Thompson Katerina V.
Published: May 2010

Flehmen, a conspicuous posture characterized by eversion of the upper lip, facilitates the transfer of nonvolatile urinary chemicals to the vomeronasal organ and therefore has been implicated in the control of reproduction in ungulates. The ontogeny of urine sampling and flehmen was investigated in semi‐free‐ranging sable antelope, Hippotragus niger, at the National Zoological Park's Conservation and Research Center because behavioural evidence suggests that flehmen is a mechanism of reproductive synchronization among females. During the first year of life, flehmen rates increased with age in both sexes. Flehmen rates of female calves equalled those of adult females by 4 months of age. Male calves first exhibited flehmen at younger ages than did female calves and showed greater increases in flehmen rate during development. Both sexes exhibited flehmen primarily after sampling urine of female conspecifics as it was being voided. During the first 2 months of life, sable antelope preferred to sample urine of other calves, but by 1 year of age adult females were the preferred targets. Females approaching sexual maturity preferred to sample urine from postpartum females (presumably resuming oestrous cycling) rather than from pregnant females, as expected if they were attempting to synchronize oestrus with experienced females. Results are consistent with the hypothesis that flehmen serves to coordinate reproduction among females and further suggest that flehmen may affect reproductive maturation.
Territoriality in Lake Eyre Dragons Ctenophorus maculosus: are Males ‘Superterritorial’?
Authors: Olsson Mats
Published: May 2010

The Australian Lake Eyre dragon, Ctenophorus maculosus, lives on dry salt lakes in the Australian interior. An unusual characteristic of this habitat is that windblown insects are the major food resource, which makes it impossible for males to defend site‐related resources. Male territory size is not correlated to male size; thus, males do not seem to defend trophic territories in relation to their own energy demands. Instead, males with higher densities of lookout sites have larger territories, and males with larger territories have more mates. In consequence, males primarily seem to guard sexual resources on territories that are not economically defensible from a trophic point of view; males appear to conform to the concept of ‘superterritoriality’ (sensu Stamps 1983).
Persistence of the Attractiveness of Two Sex‐specific Scents in Meadow Voles, Microtus pennsylvanicus
Authors: Ferkin Michael H. , Burda Jeffrey , O'Connor Megan P. , Lee Christopher J.
Published: May 2010

The function of an odour may be reflected in its fade‐out time in the environment. In this study, we investigated fade‐out times of two specific odours, the anogenital area scent and that of the posterolateral region. These two odours support opposite‐sex preferences in male and female meadow voles, Microtus pennsylvanicus, but convey nonidentical information to conspecifics during the breeding season. The first experiment tested whether meadow voles respond preferentially to scents that were aged for 15 min (fresh) to 30 d. Males preferred female anogenital area scent to male anogenital area scent if both scents were ≤ 10 d old. By comparison, females preferred male anogenital area scent to female anogenital area scent if the scents were ≤ 25 d old. However, male and female voles preferred the posterolateral scent of males to that of females if the scents were ≤ 1 d old. Thus, fade‐out times for these two scents differ for males and females, suggesting different functions. In the second experiment, male and female voles preferred fresh anogenital area scent and fresh posterolateral region scent compared with those same scents that were older. This result suggests that older scents may have lost information over time about the sex of the donor. Overall, data from both experiments indicate that voles may use specific scents for communication in different social contexts.
Is Human Handedness Universal? Ethological Analyses from Three Traditional Cultures
Authors: Marchant Linda F. , McGrew William C. , Eibl‐Eibesfeldt Irenäus
Published: May 2010

Right‐handedness inHomo sapiensis claimed to be qualitatively different from that of other primates, at species level, and to be universal across all cultures. Ethnographic indicators are sparse, however, being mostly indirect rather than direct observations of selected motor patterns. Ethological study of hand use, i.e. observation of a wide range of everyday behavioural patterns performed spontaneously, is missing. We coded such manual activity from cinematic archives of three traditional societies: G/wi San of Botswana, Himba of Namibia and Yanomamö of Venezuela. Results showed a consistent but weak right‐hand dominance across these three preliterate cultures. Most individuals showed mixed‐, rather than right‐handedness, irrespective of whether or not object manipulation was involved. The notable exception was tool use, which was markedly right‐handed, and only precision‐gripping tool use was normally performed exclusively with the right hand. Most questionnaires that measure handedness focus on precision tool use (and so are likely to be biased accordingly) rather than on more comprehensive ethological measures that include non‐object‐manipulatory, self‐directed and socially communicative patterns of behaviour.
Predator Avoidance and Alarm‐response Behaviour in Kin‐discriminating Tadpoles (Rana cascadae)
Authors: Hokit D. Grant , Blaustein Andrew R.
Published: May 2010

When captured by predators, the tadpoles of some species of frogs and toads may release an alarm substance that alters the behaviour of conspecifics. Such ‘alarm response’ behaviour has been proposed as a potential mechanism whereby related conspecifics may ‘warn’ relatives of a predator's presence and thus, improve their inclusive fitness. We examined predator avoidance and alarm response behaviour in tadpoles of the Cascades frog (Rana cascadae) and tested whether such behaviour is influenced by kinship factors. Tadpoles reduced activity when in the presence of a predatory newt (Taricha granulosa). Individuals in sibling groups were more active than both solitary tadpoles and individuals in mixed groups of siblings and nonsiblings. However, we found no evidence of an alarm response in R. cascadae. Behaviour of tadpoles in groups exposed only to predators was not different from that of tadpoles in groups exposed to predators plus crushed conspecifics. Tadpoles in groups exposed to crushed tadpoles were as active as tadpoles in groups exposed to water controls, and some test individuals fed upon the dead tadpoles. Thus, while R. cascadae tadpoles reduce activity in response to newt predators, crushed tadpoles appear to initiate a feeding response rather than an alarm response as has been previously proposed.
Social and Spatial Segregation in Alpine Ibex (Capra ibex) in Bargy, French Alps
Authors: Villaret Jean Charles , Bon Richard
Published: May 2010

Outside the rut, a gradual social and spatial segregation was observed between the sexes as male Alpine ibex (Capra ibex) aged. In addition, males joined similar‐age peer groups and segregated spatially as the age difference increased. The patterns varied seasonally, influenced by biological and ecological events. During the rut, males and females intermingled and used greatly overlapping ranges. Males ≥ 9 years first left female groups but social and spatial segregation were not complete until May. Younger males shifted to male groups more gradually. Females and males over 2 years of age used almost exclusive ranges in summer and early autumn. Social grouping and range overlap between ibex classes were correlated outside the rut. Grouping and spatial overlap between young and old males were negatively related to association with females.
Play as Indicator of Habitat Quality: A Field Study of Langur Monkeys (Presbytis entellus)
Authors: Sommer Volker , Mendoza‐Granados Domingo
Published: May 2010

The ecology and social behavior of two male bands of Hanuman langurs (Presbytis entellus) of similar size and age‐class composition were studied over 18 mo in Rajasthan, Northwest India. Play behaviour was tested as a reflection of environmental conditions. One of the bands lived in a poor habitat where food and water was often scarce, the other in a rich habitat with relatively abundant resources. For example, the proportion of fruit eaten was much higher for the rich‐habitat monkeys (RHM), whereas more than half of the diet of the poor‐habitat monkeys (PHM) consisted of leaves. The frequency of play‐fighting and locomotor‐rotational play correlated negatively with the amount of leaves eaten, probably because they are low in energy. Consequently, play rates for the RHM were not only 6–7 times higher than for the PHM, but play also lasted significantly longer. Play rates among PHM were reduced to zero during adverse environmental conditions but showed a dramatic increase when more plant food became available as a result of monsoon rains. The data provide considerable support for the hypothesis that play is a sensitive indicator of habitat quality.
Female Contests for Nest Sites and Mates in the Pied Flycatcher Ficedula hypoleuca
Authors: Dale Svein , Slagsvold Tore
Published: May 2010

Predictions of game theory models about the outcome of animal conflicts have most often been tested using male contests for mates, territories or food. We studied female contests for nest sites and mates in the pied flycatcher, Ficedula hypoleuca, and asked which factors affect the outcome and duration of the contests. Conflicts over residency were experimentally induced, but natural cases in which both females regarded themselves as owners were also included in the analyses. The ensuing escalated contests involved physical fighting, defence of the nestbox of the male and alarm calling. Contrary to expectations from game theory, fighting seemed to occur most often at the start of conflicts, whereas alarm calling occurred towards the end and nestbox visits throughout the conflict. The outcome of the contests was not determined by asymmetries in body size or age, nor by a simple previous‐present owner asymmetry. Instead, it depended on the relative residence times of the opponents. The duration of the contests tended to increase with decreasing asymmetry in the residence times of females, whereas body size asymmetries had no influence. Because there is intense competition between females for a mate in the pied flycatcher, we suggest that females do not respect asymmetries in residency and body size, but fight in relation to the value of the mating opportunity. In particular, we point to the possibility that the value of a mating opportunity may increase with residence time because knowledge of other mating options may become outdated.
Dynamics and Consequences of Hierarchy Formation in the AntLeptothoraxsp. A
Authors: Ortius Diethe , Heinze Jürgen
Published: May 2010

In the Nearctic antLeptothoraxsp. A, aggressive interactions among wingless intermorphic queens and primarily winged gynomorphic queens lead to the formation of dominance hierarchies, in which the highest‐ranking individual is the only egg‐layer in a colony. Fighting occurs during two periods of the annual cycle: in late summer, newly adopted young queens are integrated into the colony's hierarchy; after hibernation, fighting resumes and the high aggressiveness of α‐queens may now lead to the emigration of β and other middle‐ranking queens. The α‐position appears to be very stable over successive fighting periods, though an estimate of nestmate relatedness by allozyme electrophoresis (Polyacrylamide gels and cellulose acetate plates) suggests that queen replacement occasionally occurs. The mean relatedness determined for adult workers in a functionally monogynous population ofLeptothoraxsp. A was 0.54 and their effective number of mothers therefore 1.5. This is lower than expected and found for monogynous colonies. Dominance rank is apparently not correlated with queen morph, weight, and size, but an influence of insemination, age, or previous reproductive experience is likely.
Imprinting Effects on Host‐selection Behavior of Slave‐raiding Chalepoxenus muellerianus (Finzi) Workers (Hymenoptera: Formicidae)
Authors: Schumann Ralf D. , Buschinger Alfred
Published: May 2010

Early experience is known to influence brood care behavior and to induce nesting preferences of several ant species. Scanty information is available with respect to imprinting effects on host selection of dulotic ants. In this paper we investigate host choice behavior of workers of the slave‐making ant, Chalepoxenus muellerianus. As in a corresponding paper (Schumann & Buschinger 1994) on host specificity of C. muellerianus young queens during colony foundation, we demonstrate that a blend of innate factors and effects of early experience also influences host species selection of slave‐raiding workers.
Sexual Imprinting in Zebra‐finch Females: Do Females Develop a Preference for Males that Look Like Their Father?
Authors: Vos Dave R.
Published: May 2010

Recently, it has been proposed that through sexual imprinting on their parents, young birds learn to discriminate between males and females. Support for this suggestion was given by a study on zebra‐finch males Taniopygia guttata, which showed that males of this species develop a strong sexual preference for mother‐like females over father‐like females. The present study investigates whether zebra‐finch females also develop a sexual preference for mates resembling the opposite‐sex parent. The females used had been raised either by normal pairs, by white pairs or by pairs of both morphs. The preferences were tested by confronting these females with normal and white males, both in simultaneous two‐stimulus tests and successive one‐stimulus tests. In contrast to males, females raised by a pair of mixed‐morph parents did not show a preference for mating partners of the opposite‐sex‐parent's morph. Instead, they showed a preference for males of the mother's plumage type. It is suggested that the difference in which sexual imprinting proceeds in males and females may be related to the different role each sex plays in the pair formation.
Essay on Contemporary Issues in Ethology: Behavioral Ecology and the Study of Partner Choice
Authors: Dugatkin Lee Alan , Sih Andrew
Published: May 2010

Female mate choice has been studied extensively by behavioral ecologists and ethologists. Mate choice is, however, only one form of 'partner choice'. Recent experimental work has demonstrated the existence of partner choice in many other contexts, for example, antipredator behavior, foraging behavior, mate searching, and anti‐parasite decisions. These studies have revealed important new insights for the study of partner choice. We review these studies, and suggest how they might both pave the way for future work in this area and provide the underpinnings for a comprehensive conceptual framework for studying partner choice.
Escape Tactics and Alarm Responses in Badgers Meles meles: A Field Experiment
Authors: Butler Juliana M. , Roper Timothy J.
Published: May 2010

A typical badger (Meles meles) territory contains a primary burrow or 'main sett' plus several secondary burrows or 'outlier setts'. The main aim of our study was to test the hypothesis that outlier setts are used as emergency refuges, by subjecting foraging radio‐collared badgers to three levels of experimental disturbance (low, moderate and high). In addition, we recorded the occurrence of potential alarm signals. With low‐level disturbance, badgers usually returned to the main sett even when this was further away than the nearest outlier sett; with high‐level disturbance they always took refuge in the nearest outlier; and with moderate‐level disturbance they showed no clear preference. We conclude that outlier setts do act as emergency refuges, but only when an animal is badly frightened. Possible alarm signals (pilo‐erection, head‐flagging, snorting and growling) occurred mainly during moderate or high‐level disturbance but even then they were relatively infrequent. Signals were no more likely to be emitted when conspecifics were near by than when the signaller was alone, and when conspecifics were present they rarely reacted either to the flight of the disturbed animal or to any signals that it emitted. We conclude that such alarm signals as do occur constitute threats directed towards the predator rather than warnings for the benefit of conspecifics.
Navigation in Familiar Environments by the Weakly Electric Elephantnose Fish, Gnathonemus petersii L. (Mormyriformes, Teleostei)
Authors: Cain Peter
Published: May 2010

Gnathonemus petersii use electrolocation to navigate in unfamiliar environments. The goal of these experiments was to determine whether fish could learn the location of a fixed aperture after interference with selected sensory input. By manipulating environmental cues (aperture height and water depth) and comparing the fish's performance, the contributions of the electrosensory system, vision, and hydrostatic pressure were examined. The fish's task was to find a circular aperture in a wall dividing a 200‐litre aquarium into two equal compartments. In experiment 1, the position of the aperture was raised by 10.1 cm after the fish had become familiar with its original location. In experiment 2, the water level was raised by 10 cm (leaving the aperture unchanged). When the aperture was raised, intact fish found the new aperture with no difficulty, whereas blind, electrically 'silent', and sham‐operated fish were slow finding the new position. When the water level was raised, all fish increased the height at which they contacted the wall, increased their electric‐organ discharge (EOD) rate, and located the aperture. This increase, in response to the rapid change in water depth, suggests that all fish used hydrostatic pressure cues to maintain depth orientation, and that those fish that learned the aperture height had used hydrostatic cues to locate its position. The data suggest that G. petersii develop an internal representation based on an electrosensory central expectation and hydrostatic cues. The fish develop a sensory 'image' of their immediate environment and associate a specific image with a specific depth. As the environment becomes more familiar, the fish apparently attend less to electrosensory information and navigate according to the internal representation, relying primarily on hydrostatic pressure cues.
Ability of Female Squirrel Monkeys (Saimiri sciureus) to Discriminate between Conspecific Urine Odours
Authors: Laska Matthias , Hudson Robyn
Published: May 2010

In this study, an odour‐conditioning paradigm was used to investigate the ability of captive squirrel monkeys, Saimiri sciureus, to discriminate between urine odours of conspecifics. It was found that the three test females could: 1. Readily discriminate between urine from conspecifics and other primate species; 2. Discriminate between urine from individual conspecifics, whether unfamiliar animals or members of the test animals' social group, and whether or not they were of the same sex; and 3. Not discriminate so easily between urine from genetically related conspecifics as between urine from unrelated individuals, particularly where both donors were female. The findings suggest that an individually distinct and stable factor is present in squirrel‐monkey urine, that this is more similar in genetically related than unrelated individuals, and that, in males, some additional source of individual variability exists enabling the discrimination of even close relatives. While the biological significance of these findings remains to be investigated, this study demonstrates that squirrel‐monkey urine contains a considerable amount of information of potential signal value.
Infanticide by Adult and Subadult Males in Free‐ranging Red Howler Monkeys, Alouatta seniculus, in Venezuela
Authors: Agoramoorthy Govindasamy , Rudran Rasanayagam
Published: May 2010

After 15 males invaded troops of wild red howler monkeys (Alouatta seniculus) present in Venezuela during the period from Apr. 1989 to May 1991, five infant killings and eight infant disappearances occurred. Among the eight groups that were invaded, 10 infants of less than 3 mo old and three of over 5 mo old were killed either by the adult or subadult males, or disappeared. However, on the five occasions of invasion, none of the nine infants were killed. In two other groups, there were no infants present at the time of invasion. It was also noted that no infant of kin of the invading males was killed. At least six of the females that had lost their infant during such invasion subsequently copulated both with the invader as with the original resident male. In one case, a female copulated with the resident male of a neighbouring group. In the four cases of subadult males committing infanticide there was no immediate sexual access to the females. The data presented here are inconsistent with the reproductive sexual‐advantage hypothesis, but consistent with the hypothesis concerning food competition.
Honeybee Long‐distance Orientation in a Controlled Environment
Authors: Chittka Lars , Geiger Karl
Published: May 2010

The integration of artificial movable landmarks (tetrahedral tents of 3.46 m height) into the longdistance course control of bees was investigated in an environment that provided a minimum of natural orientation cues. Bees were trained along a row of four landmarks which were equally spaced in a setup of 300 m in length. The animals were then tested in situations where the position of the landmark line indicated a direction of the feeding site other than the (originally trained) sun‐compass direction. This discrepancy was systematically varied. We show that the sun compass is dominant over the landmarks. This preference is negligible if the deviation between the two indicated directions is small, but it increases as the angle of deviation becomes larger. In contrast, if the entire sky is overcast by clouds, more bees will follow the direction indicated by the artificial landmarks than under sunny conditions. However, as the deviation between the trained direction and the landmark direction increases, more individuals will land at the training site.
Does Polymorphism Protect? An Experiment with Human ‘Predators’
Authors: Knill Rebecca , Allen John A.
Published: May 2010

Polymorphism in cryptic prey species may be ‘protective’, in the sense of reducing the rate of predation by visual predators. We tested this supposed function by presenting 80 schoolgirls (aged 12–13) with populations of square ‘prey’ on backgrounds displayed on computer screens. The backgrounds were composed of random distributions of small coloured squares and the prey were composed of the same small squares, the grid of the prey being parallel to (but usually imperfectly aligned with) that of the background. Different ‘morphs’ of prey were defined by the spatial distribution of the small squares, and prey of a given morph were always presented in the same orientation. Each subject was presented with a sequence of 40 screens, of which 36 were background containing a single randomly positioned prey, while four were background alone. Subjects ‘zapped’ prey with the mouse, or pressed the space bar if the screen was judged to be empty, and then moved automatically to the next screen in the sequence. Each subject received a single ‘treatment’: high or low crypsis combined with one of four levels of polymorphism (1, 2, 6 or 12 morphs). The results showed that hit (‘predation’) rate tended to be lower on populations with high crypsis and was inversely related to the number of morphs in the population. We thus conclude that polymorphism may indeed ‘protect’.
Influence of Movement by Coho Salmon (Oncorhynchus kisutch) Parr on Their Detection by Common Mergansers (Mergus merganser)
Authors: Martel Guy , Dill Lawrence M.
Published: May 2010

A common reaction in juvenile salmonids that detect predators is to decrease activity. To test whether there is a survival advantage to reduced movement under such circumstances, juvenile coho salmon (Oncorhynchus kisutch) were placed with common mergansers (Mergus merganser) under laboratory conditions that precluded crypsis. Mergansers were more likely to attack fish that moved than fish that remained stationary, and the relation between the lag time for detection by the birds and fish movement rate is best described as inversely exponential. The lag time for detection was not correlated with fish size. The risk of detection of prey by visual predators should be determined by both predator and prey behaviour, but our results suggest that in this case prey behaviour is more important. In the field, territorial coho juveniles do feed more and grow faster than other, non‐territorial fish. They also spend a smaller proportion of their time moving. The present experiment suggests that territorial coho may also suffer less mortality than non‐territorial fish, which would lower their ratio of mortality risk to growth rate.
Males Choose Larger Females as Mates in the Salamander Desmognathus santeetlah
Authors: Verrell Paul A.
Published: May 2010

Intrinsic constraints resulting in temporally‐limited mating capacity may select for ‘prudence’ in the allocation of sexual resources by male salamanders. Prudence in the form of male mate choice was examined in a dusky salamander, Desmognathus santeetlah (Plethodontidae). Males mated with small and larger females at similar rates when presented sequentially with potential partners differing in snout‐vent length. However, males were more likely to mate with larger females when presented simultaneously with two potential partners that differed in snout‐vent length by at least 4 mm. The greater mating success of larger females was due to male mate choice for more fecund partners. Behavioural observations of trios composed of one male and two females revealed that males experienced ample opportunities for partner assessment that were uninfluenced by direct interactions between females. Male choice for larger females may confer an advantage on choosy males because female fecundity is positively correlated with body size in D. santeetlah: larger females carry more eggs available for fertilization. The occurrence and value of male mate choice in natural populations, where males compete for partners and females mate multiple times, remain to be determined.
Satellite Male Groups in Horseshoe Crabs, Limulus polyphemus
Authors: Brockmann H. Jane
Published: May 2010

Horseshoe crabs arrive on the beach in pairs and spawn in the high intertidal during the springtime, new and full moon high tides. Unattached males also come to the beach, crowd around the nesting couples and compete with attached males for fertilizations. Satellite males form large groups around some couples while ignoring others, resulting in a nonrandom distribution that cannot be explained by local environmental conditions or habitat selection. In experimental manipulations, pairs that had satellites regained them after they had been removed whereas pairs with no satellites continued nesting alone, which means that satellites were not simply accumulating around the pairs that had been on the beach the longest. Manipulations also revealed that satellites were not just copying the behaviour of other males. Based on the evidence from observations and experiments, the most likely explanation for the nonrandom distribution of satellite males among nesting pairs is that unattached males are preferentially attracted to some females over others. Females with many satellites were larger and in better condition, but did not lay more eggs, than females with few or no satellites.