bluuebunny/crossref_metadata_2025 huggingface dataset:
Mate Sampling and Assessment Procedures in Female Pied Flycatchers (Ficedula hypoleuca)
Authors: Hovi Matti , Rätti Osmo
Published: May 2010

Models of mate sampling strategies predict that choosiness should decrease throughout the breeding season due to increasing costs of delaying mating. Therefore, individuals who start searching mates relatively late, should spend less time on sampling, and sample fewer candidates compared to early individuals. We observed mate searching behavior of female pied flycatchers (Ficedula hypoleuca) by radio‐tracking in study areas with 6–12 unpaired males. Contrary to the prediction, the observed numbers of males sampled by the searching females increased with time, i.e. late arriving females visited more males than early arrivers. However, this seems to be due to more active sampling of males in short time by late‐arriving females. The observed sampling pattern suggests some kind of comparison tactic, which seems, however, to be very variable among individual females. Mate‐assessing females were characterized by a remarkably cryptic behavior, which may be 1) a way of gaining honest information about the male mating status or male/territory quality, or 2) a way of avoiding courtship costs.
The Influence of Substrate Color on the Alarm Response of Tidepool Sculpins (Oligocottus maculosus; Pisces, Cottidae)
Authors: Houtman Robert , Dill Lawrence M.
Published: May 2010

For animals that use crypsis to avoid predators, immobility reduces the risk of detection. The magnitude of this immobility benefit depends upon the probability that a predator is present, since a predator must be present for crypsis to be valuable. Thus, cryptic animals typically reduce their movement rates upon detection of a nearby predator or signs of its activity. Such a response occurs in tidepool sculpins (Oligocottus maculosus) when presented with water‐borne compounds released from the skin of injured conspecifics (Hugie et al. 1991). The benefit of immobility should also depend upon the animal's background, or substrate, since animals on a matching substrate achieve a higher level of crypticity than those on a nonmatching substrate, and have more to gain by remaining still. Therefore, we predicted that the response of tidepool sculpins to conspecific skin extract would involve a greater reduction in movement rates for fish on sand (matching) than for those on white (nonmatching) substrate. The results of a laboratory experiment supported this prediction, with fish on sand showing a large decrease in movement rates in response to skin extract, while the movement rates of those on white substrate remained unchanged.
The Dilution Effect and Differential Predation Following Brood Adoption in Free‐ranging Convict Cichlids (Cichlasoma nigrofasciatum)
Authors: Wisenden Brian D. , Keenleyside Miles H. A.
Published: May 2010

Parental investment in unrelated offspring is potentially maladaptive but may be promoted by natural selection if the presence of foreign young enhances the survival of the parents' own young. We experimentally augmented broods of free‐ranging convict cichlids (Cichlasoma nigrofasciatum) to test whether survival of the adopting parents' young (fry) increases, in relation to that of control broods, after the addition of smaller foreign fry, and whether such an increase can be attributed to the effect of brood dilution acting alone or to a combination of brood dilution and the effect of differential predation on adopted young. Total fry survival did not differ between experimental (E) broods and control (C) broods, but E broods had significantly more large (host) fry after 5 days and 10 days than C broods did. In E broods, small (foreign) fry suffered higher rates of predation than large fry, indicating differential predation. In E broods starting at 7.0 and 7.5 mm standard length (SL), observed fry mortalities did not differ significantly from mortalities expected from the effect of brood dilution. However, E broods starting at 8.0 mm SL had significantly lower mortalities than expected, indicating that parents that adopt smaller foreign fry can increase the survival of their own fry by the combined effects of brood dilution and differential predation. Within E broods, growth of smaller foreign fry was significantly slower than that of larger host fry, suggesting that intra‐brood agonistic behaviour affects access to food for smaller fry. Therefore, increased predation and reduced growth are two negative effects that act on fry of donor parents.
Alternative Male Spawning Tactics and Acoustic Signals in the Plainfin Midshipman Fish Porichthys notatus Girard (Teleostei, Batrachoididae)
Authors: Brantley Richard K. , Bass Andrew H.
Published: May 2010

The plainfin midshipman Porichthys notatus has two male reproductive morphs, ‘Type I’ and ‘Type II’, which are distinguishable by their physical traits alone. Type I males are eight times larger in body mass than Type II males and have a six‐fold larger relative sonic (vocal) muscle mass than Type II males. In contrast, the testicles of Type II males are seven times larger than those of Type I males. This study demonstrates morph‐specific patterns of reproduction, including acoustic signals, for Type I and II males. Field censuses of nests showed that only Type 1 males maintained nests. Type II males and females transiently appeared in these nests in association with each other. Infra‐red video and hydrophone recordings in aquaria showed that Type I males maintained nests and readily vocalized. Long‐duration ‘hums’ and sequences of short‐duration ‘grunts’ were produced during advertisement and agonistic contexts, respectively. Humming Type I males attracted females to their nests, pair‐spawned, and then guarded egg clutches alone. By contrast, Type II males neither acoustically courted females nor maintained available nest sites, but rather ‘sneak‐’ or ‘satellite‐spawned’ at the nests of Type I males. Type II males infrequently produced low amplitude, short duration grunts that were similar in spectral, temporal and amplitude characteristics to the grunts of females. Type II males appear to be obligate sexual parasites of the nest‐building, mate‐calling, and egg‐guarding Type I males. The dimorphic body and vocal muscle traits of the two male morphs in the plainfin midshipman are thus paralleled by a divergence in their reproductive tactics and the properties of their acoustic signals.
Age, Experience, and the Response of Streamside Salamander Hatchlings to Chemical Cues from Predatory Sunfish
Authors: Sih Andrew , Kats Lee B.
Published: May 2010

Previous work has shown that streamside salamander larvae (Ambystoma barbouri; Ambystomatidae) exhibit an adaptive ‘sink to the bottom’ response to chemical cues from predatory green sunfish (Lepomis cyanellus; Centrarchidae), that is, larvae sink to the bottom more quickly (thus minimizing exposure time to sunfish predation) when they are dropped into water with sunfish chemicals (as compared to Ashless controls). Here, we examined this anti‐predator behaviour in early hatchlings and the effects of age and experience on subsequent expression of this behaviour. Hatchlings responded significantly to fish chemical cues within the first 18 h after hatching. Age did not significantly influence this response, i.e. regardless of age (1, 7, or 14 days after hatching) larvae showed a significant response during their first exposure to fish chemical cues. Experience also did not significantly influence the larval response to fish chemicals i.e., repeated exposures over 2 weeks did not significantly influence the magnitude of the response. Finally, comparisons of 3 siblingships detected significant variation among siblingships that might reflect genetic variation in this behaviour.
Nocturnal Mate Recognition and Nest guarding by Female Convict Cichlids (Pisces, Cichlidae: Cichlasoma mgrofasciatum)
Authors: Reebs Stephan G.
Published: May 2010

This study investigated the ability of nest‐guarding convict cichlid (Cichlasoma mgrofasciatum) females to recognize their own mate and to defend their brood effectively against strangers at night. Cichlids in the laboratory bred in nesting boxes made of plexiglas. At the fry stage, various conspecific males were introduced, at night, into the nest box of brood‐guarding females. Female reaction was observed with infrared equipment. If the introduced male was their own mate, females showed little reaction. If the introduced male was a stranger, females reacted by directing head shakes, tail beats, and pushes or bites at the intruder. The frequency of these acts was significantly higher in the presence of strangers than in the presence of mates; the frequency also rose significantly as the size of strangers increased. The two largest classes of strangers fought with the females. These fights included circling behaviour, but not mouth‐locking. Some aspects of female behaviour suggested that mate recognition is based on short‐range chemical cues and not on sound, size, or rapidly diffusing odours. Mate recognition in the nest, at night, is an example of non‐visual communication in fish, and active nest defense at night shows that the convict cichlid, normally considered to be diurnal, can engage in coordinated and effective behaviour in the absence of light.
Imprinting Effects on Host‐Selection Behaviour of Colony‐FoundingChalepoxenus muellerianus(Finzi) Females (Hymenoptera, Formicidae)
Authors: Schumann Ralf D. , Buschinger Alfred
Published: May 2010

Host selection behaviour during colony foundation of newly inseminatedChalepoxenus muellerianusfemales belonging to three different imprinting types was investigated. Imprinting occurs both in larvae and in the young adults. It strongly influences the slavemakers' host choice. Young females get imprinted onto that slave species which is already present in the slavemaker colony. If nests of several potential host species are present in the habitat, the females will prefer the ‘familiar’ species for colony foundation. In addition to the imprinting influences, an innate preference ofC. muellerianusfor its main host speciesLeptothorax unifasciatuswas demonstrated. Host selection behaviour ofC. muellerianusfemales therefore depends on a blend of innate and learned characters. A genetically mediated preference of a certain host species can be reinforced by imprinting‐like phenomena. On the other hand, the same processes probably facilitate a change of the host species, for example in habitats, where the main host species is rare, and females are forced to switch over to other potential host species for colony foundation.
Parasites and Female Ability to Defend Offspring in the Parent Bug Elasmucha grisea L
Authors: Mappes Johanna
Published: May 2010

The specialist endoparasite Subclytia rotundivertis Fallen (Diptera; Tachiniidae) uses the subsocial parent bug Elasmucha grisea L. (Heteroptera; Acanthosomatidae). The parasite injects a single egg through the upper prothorax of female bugs and after hatching the larval parasites eat their host. Parasitism affected only slightly a female's ability to defend her brood when the nymphs were at the second instar stage. However, with third‐instar nymphs, parasitized females responded markedly less to disturbance at all levels of their defensive behaviour. Parasitism reduced female survival and significantly increased the probability of death before the end of maternal care. Thus, the main cost of parasitism to Elasmucha females seems to be a reduced period of maternal care of the nymphs.
Alternative Mate‐locating Tactics in Chlosyne californica (Lepidoptera, Nymphalidae)
Authors: Alcock John
Published: May 2010

Two different mate‐locating tactics coexist within the California patch butterfly (Chlosyne californica): territorial defence of perch sites on hilltops and non‐territorial patrolling of slopes and washes. Patrolling males were observed only during periods of high population density. At these times, some marked individuals used both tactics, indicating that they possessed the behavioural flexibility to practice either hilltop territoriality or downslope patrolling. Downslope patrolling was not simply a ‘making‐the‐best‐of‐a‐bad‐job’ option for males unable to secure territories. First, patrollers were not smaller on average than territorial males. Second, downslope patrollers typically became most numerous several hours after the hilltopping territorial males peaked in density. In the late morning and midday when patrollers predominated, temperatures were relatively high (perhaps facilitating patrolling flight) and foraging females (some of which were sexually receptive) were much more abundant. Patrolling is therefore likely to be a mate‐locating supplement to hilltopping rather than an inferior substitute for it.
Role of Helpers in the Sentinel Behaviour of the Florida Scrub Jay (Aphelocoma c. coerulescens)
Authors: Hailman Jack P. , McGowan Kevin J. , Woolfenden Glen E.
Published: May 2010

Two independently conceived and executed field studies using somewhat different methodologies tested the hypothesis that non‐breeding helpers of the Florida scrub jay (Aphelocoma c. coerulescens) contribute importantly to antipredator sentinel behaviour. Specifically, we made four predictions: 1. Helpers participate to a non‐trivial degree in sentinel behaviour; 2. Breeding pairs with helpers spend less time on sentinel behaviour and hence more time foraging; 3. Breeders with helpers have more protected foraging time; and 4. Groups with helpers have greater total sentinel time.

Results of the two studies agreed on most major points and even, in many cases, on minor points and quantitative aspects. Non‐breeding adult helper birds participated in sentinel watches almost as much as breeders in their group. In winter, breeding pairs with one or more helpers decreased their own sentinel time compared with that of unassisted pairs. However, in the one study, the concomitantly increased available foraging time of breeders was no better protected by another group member being on sentinel than in the lone pairs. Results of the other study showed a significant increase of protected foraging time for breeding males only. In winter, groups with helpers did not have increased total sentinel time; time was either the same (Study A) or significantly less (Study B). During nesting, breeders with helpers did not decrease their sentinel effort relative to lone pairs. Instead, groups with helpers had a sentinel for more time. These results are interpreted as indicating that, in winter, sentinel behaviour is more important to antiraptor defense in lone pairs than larger groups. In groups with helpers the mere addition of extra pairs of eyes and ears may render formal sentinel behaviour less necessary, so breeders can decrease their sentinel time and increase their foraging time. During nesting, additional sentinels may be important for increased nest protection. The presence of helpers contributing to predator detection may thus be an important factor in the better annual survival and nesting success of breeders that have helpers (Woolfenden & Fitzpatrick 1984).
Kin‐biased Behaviour in Male Wild House Mice: Mixed‐paternity Grouping and Group Member versus Kin Discrimination
Authors: Smith Jeremy , Barnard C. J. , Hurst Jane L.
Published: May 2010

Kin bias during social interaction among house mice (Mus musculus) is influenced by learned odour cues used by the animal when encountering and interacting with other individuals. In this experiment with wild mice, the source of these odour cues was investigated by cross‐fostering single male pups between unrelated litters to create mixed‐paternity litters. Observation of dyadic interactions involving juvenile or adult mice reared in mixed‐paternity litters and unfamiliar animals reared in single‐paternity litters showed a bias in social investigatory and passive contact behaviours towards (a) an individual's own kin or the kin of an unrelated foster‐littermate and (b) the unrelated foster‐littermate of a relative, compared with (c) an unfamiliar unrelated control. The functional significance of kin bias is discussed in the light of the role of odour cues in recognizing familiar social group members and the transfer of odours between individuals within groups.
Copulation‐solicitation Displays in Female Canaries (Serinus canaria): are Oestradiol Implants Necessary?
Authors: Leboucher Gerard , Kreutzer Michel , Dittami John
Published: May 2010

The aim of this study was twofold: 1. To study the timing of copulation‐solicitation displays (CSD) in female canaries during a natural breeding cycle; 2. To address the question of the adequacy of invasive methods such as oestradiol treatment. Towards these ends, we compared seven oestradiol‐implanted and eight control females. Moreover, temporal relationships between reproductive behaviour and plasma concentrations of luteinizing hormone and oestradiol were investigated.

The results showed that: 1. CSD appeared about 3 d before egg laying, after the peak of nest building. The maximum number of CSD was observed at the beginning of egg laying. CSD disappeared when the last egg was laid, at the very beginning of incubation; 2. No significant difference was found between the two groups for any behavioural criterion, particularly CSD. No significant difference appeared between control and oestradiol‐treated females for luteinizing hormone concentrations. In contrast, oestradiol‐implanted females presented higher levels of oestradiol during nest building and during egg laying, 9–13 d after implantation (median 2.53 and 1.47 ng/ml for implanted females vs 0.57 ng/ml and undetectable levels for controls). Implantation had no effect on the progress of nest building, CSD exhibition, egg laying and incubation. Our results suggest that implantation with oestradiol is not necessary in female canary to obtain CSD since they breed readily in captivity and already have enough oestradiol. The similar results in both groups lead one to question the necessity of oestradiol priming in some female choice experiments.
Prey‐handling Behaviour of Newly Hatched Snakes in Two Species of the Genus Elaphe with Comparison to Adult Behaviour
Authors: Mori Akira
Published: May 2010

The prey‐handling behaviour of two species of Asian ratsnakes was studied in the laboratory. In experiment 1, effects of prey size and type (mouse, lizard and frog) on capture position, direction of ingestion, condition of prey at ingestion, and prey‐handling method were investigated using newly hatched Elaphe quadrivirgata. Prey size did not affect these variables except prey‐handling method in frog trials: large frogs were more frequently constricted after a delay of more than 1 s than small frogs, and small frogs were usually simply seized. On the other hand, prey type affected prey‐handling method: mice and lizards were more frequently constricted or pinioned than frogs. When hatchlings of E. quadrivirgata tried to coil around a prey animal immediately after striking, they frequently failed or released their coils within 10 s after striking. In experiment 2, prey‐handling behaviour of adult E. climacophora was examined with mice of various sizes. Adult E. climacophora tended to constrict large mice immediately after striking, whereas they simply seized small mice. Only one out of 38 mice which were constricted immediately after striking was released from the coils within the subsequent 10 s. Large mice were killed prior to ingestion, whereas small mice were swallowed alive. Large mice tended to be swallowed head first. Experiment 3 was conducted to investigate effects of mouse size on prey‐handling behaviour of newly hatched E. climacophora. Mouse size affected condition of prey at ingestion and prey‐handling method but not capture position and direction of ingestion. Possible relationships between feeding ecology and the differences of prey‐handling behaviour among Elaphe are discussed.
Adoption Behaviour in Little and Common Terns (Aves; Sternidae): Chick Benefits and Parents' Fitness Costs
Authors: Saino Nicola , Fasola Mauro , Crocicchia Elena
Published: May 2010

Adoption seeking by semi‐precocial chicks of some bird species can be adaptive since it provides an alternative tactic to permit poorly cared‐for young to survive despite their neglectful parents' behaviour. Moreover, own‐nest desertion may enhance inclusive fitness of fugitive chicks by increasing survival prospects of siblings. On the other hand, adoption by breeding adults can be detrimental to foster parents' fitness if they invest resources in promoting survival of others' offspring at the expense of their own. In this study we report on the proximate causes and survival consequences of adoption seeking by chicks, and on the presumed costs of adoption sustained by foster parents in two colonial, ground‐nesting tern species: the little tern (Sterna albifrons) and the common tern (Sterna hirundo). Adoptions were frequent in little tern and, notably, in common tern colonies. Chicks that deserted their original brood were poorly fed compared with resident chicks, but crowding in the brood and age rank relative to nest companions did not influence the chances of desertion. Deserting their original brood was risky for little tern chicks since stray chicks experienced higher mortality than resident ones. Common tern chicks deserted their original nest significantly more often than little tern chicks. Adoptees of both species benefited by the same survival prospects as resident chicks. A negative correlation existed between the proportion of food given to strange chicks and seasonal fitness or chick survival rate of breeding pairs. This was not predictable because: (1) foster parents could have increased their parental efforts, thus ensuring the same survival prospects to their own chicks, and (2) chicks of foster parents could have been, in turn, adopted thus obliterating the negative fitness effects of adoption. The sexes were identical with respect to their proneness to provide food to strange chicks. We suggest that adoption seeking by little and common tern chicks has evolved as an alternative tactic that is pursued to counter the effects of poor parental care. Adoption behaviour seems maladaptive since it is accompanied by a reduction in seasonal fitness in both species. Possible alternative explanations for nest desertion and adoption behaviour are also discussed.
Matched Counter‐singing Signals Escalation of Aggression in Black‐capped Chickadees (Parus atricapillus)
Authors: Shackleton Scott A. , Ratcliffe L.
Published: May 2010

Black‐capped chickadees (Parus atricapillus) have the ability to shift their songs up and down over a wide range of absolute frequencies. Males can shift their songs over 465 ± 52.9 (SE) Hz. During the dawn chorus, males shift their songs by 80 Hz or more every 41 ± 8.8 (SE) songs, but it appears that males can sing at any frequency within their range. Frequency shifting may allow males to match counter‐sing with rival males; that is, to switch song output to match that of a rival. During simultaneously recorded dawn choruses, however, there was no correlation over time in the frequency of neighbouring males' songs, nor was there a correlation over time in the size of shifts between their songs. Moreover, males did not match the frequencies of songs presented on a played‐back tape at the edge of their territories during the dawn chorus. Matching was observed during some bouts of counter‐singing between males. In these cases, matched counter‐singing was highly associated with escalation of the conflict. We suggest that frequency matching in this species may be a graded signal that allows the singer to direct aggression towards a particular rival.
Habituation, Recovery and the Similarity of Song Types within Repertoires in Red‐winged Blackbirds (Agelaius phoeniceus) (Aves, Emberizidae)
Authors: Searcy William A. , Coffman Stephan , Raikow David F.
Published: May 2010

Male red‐winged blackbirds (Agelaius phoeniceus) respond to playback of conspecific song on their territories with the song spread, a graded aggressive display in which males extend their wings to expose their red epaulets while singing. We show that the intensity of song spread display declines with repeated presentation of one song type, and recovers when song types are switched. Recovery is greater for switches between song types that are acoustically dissimilar than for switches between song types that are acoustically similar. Recovery is no different for switches between two song types taken from the repertoires of different males than for switches between song types recorded from the same male. Analysis of acoustic features also indicates that song types recorded from different males are not more dissimilar than are song types from the same male. Our results do not support the idea that repertoires of red‐winged blackbirds are composed of similar song types in order to facilitate individual recognition. Rather, repertoires may be constructed of dissimilar song types, so as to help maintain the response of listeners despite habituation.
Timing of Spawning and Host‐nest Choice for Brood Parasitism by the Japanese Minnow, Pungtungia herzi, on the Japanese Aucha Perch, Siniperca kawamebari
Authors: Baba Reiko
Published: May 2010

A field study of the breeding ecology of the Japanese aucha perch, Siniperca kawamebari, and brood parasitism by the Japanese minnow, Pungtungia herzi, on nests of the perch was carried out from 1989 to 1991. Observations of perch nests under natural conditions in 1990 showed that brood parasitism by the minnow was concentrated on host nests in which nest owners had just begun their nesting cycle. When spawned in a perch nest with recently spawned perch eggs, parasite eggs always hatched earlier than host eggs. An experiment with imitation perch eggs in 1991 confirmed that changing colour of host eggs was the cue for the parasites to distinguish between different developmental stages of host eggs. Parasite eggs rapidly disappeared without guarding by a host male (Baba et al. 1990). This loss was caused by predation by fishes. Parasite fry left the nest immediately after hatching, so parasite eggs spawned in a host nest in an early stage should be well guarded until they hatch. In the field, minnows deposited their eggs in perch nests which had larger numbers of newly spawned perch eggs. Since the perch males always deserted their nests when their own eggs disappeared, the parasite's choice of host nests with larger numbers of host eggs may ensure survival of the parasite eggs. The timing of egg deposition and choice of host nest by the minnow appear to be adaptive in terms of brood parasitism on nests of the perch.
Parabiosis and its Proximate Mechanisms in Four Kalahari Desert Tenebrionid Beetles
Authors: Rasa O. Anne E.
Published: May 2010

Four nocturnal desert tenebrionids with complete ecological niche overlap as adults form daytime aggregations in burrows in species pairs, Eremostibes with Parastizopus and Herpiscius with Gonopus. Parastizopus and Gonopus were the primary burrowers, the associations being initiated by the smaller partners. Association was not dependent on differences in temperature preference between species nor only on the ecological conditions the larger beetles provided. Partner species were preferred over other tenebrionids of the same size. The proximate segregating mechanism was avoidance of the non‐partner by the smaller species. Avoidance was odour‐mediated in Eremostibes, which also showed an equal odour‐based preference for conspecifics and Parastizopus. Odour profile similarity between the two was hypothesized as the mechanism permitting coexistence. An odour‐mediated preference for Gonopus or conspecifics could not be shown for Herpiscius, nor was Parastizopus odour avoided. Here, a higher relative humidity in inhabited burrows was suggested as the proximate factor promoting association. A possible advantage of aggregation for desert tenebrionids is discussed.
Rats Work for Food They then Reject: Support for the Information‐primacy Approach to Learned Industriousness
Authors: Inglis I. R. , Shepherd D. S.
Published: May 2010

There is good evidence that in many situations, animals prefer to work for food even when identical food is freely available. This phenomenon is called ‘learned industriousness’ or ‘contrafreeloading’ and has been found in several species. This study shows that wild rats will also work hard for contaminated food that they associate with sickness and subsequently reject, even when wholesome food is continuously available at no extra cost.

Seven wild rats (Rattus novegicus) lived for 4 wk in cages containing two operant levers and associated pellet dispensers. The rats earned all their food by lever pressing for 45‐mg food pellets on a variable‐interval 10 s (VI10s) schedule in each dispenser. After 1 wk, pellets containing a sub‐lethal dose of an acute rodenticide were available for 12 h (the test period) from the preferred dispenser, before being replaced by normal food pellets. This procedure was repeated 1 wk and 4 wk later. The number of lever presses, pellets delivered, and pellets consumed at each dispenser were recorded for 12 h prior to the test period, during the 12‐h test period, and 12 h after the test period.

The rats quickly learned to shift their feeding preference during the test period away from the dispenser that provided the rodenticide pellets. However, during the second half of the test period, lever pressing at this dispenser increased, even though the pellets thereby obtained were still rejected. This divergence between the lever pressing rate and the pellet consumption rate increased over the three trials.

This ‘learned‐industriousness’ behaviour is not easily explained by the self‐reinforcing hypothesis, by the obligate species‐specific response hypothesis, or as some artefact of the operant situation. It is suggested that the lever pressing towards the end of the trial, for pellets that were rejected, enabled the animals to gather information about a rare, but very important, event, namely, the presence of dangerous food at a previously preferred and normally safe feeding site. The data lend support to the information‐primacy theory of learned industriousness.
Migratory Orientation of Passerines at Dusk, Night and Dawn
Authors: Åkesson Susanne , Sandberg Roland
Published: May 2010

The orientation of four different species of nocturnal passerine migrants was investigated in spring and autumn by orientation‐cage experiments at dusk, night, and dawn under natural clear skies. Our objective was to examine the orientation behaviour at different periods of a nocturnal migration flight, and to relate the orientation to visual orientation cues (the position of the sun). In robins, the mean orientation was W (autumn) and NW (spring) in the evening tests, N (both autumn and spring) in the middle of the night, and NE (both autumn and spring) at sunrise. The northerly mean orientation at night in both spring and autumn, agreed well with the expected migratory direction for robins (reoriented migration in autumn) as shown by ringing recoveries. A clockwise shift in mean orientation throughout a nocturnal migration flight period (spring and autumn) indicates that the birds may not compensate fully for the azimuthal change of either sun or stars at the horizon. Migratory activity was highest at dusk and dawn, with a reduction in activity in the middle of the night. Spring tests revealed a significantly higher incidence of migratory activity during the second h after sunset than in the autumn tests, indicating longer flights in spring when the birds are approaching the breeding areas. For pied flycatchers, redstarts and lesser whitethroats, the directional choices during spring were between NW and N in evening tests while the dawn experiments showed mean directions towards NE or E. A compromise orientation was observed during both spring and autumn between the expected migratory direction for the season and the position of the sun at both sunset and sunrise, resulting in orientation more to the north of the sun in spring and more to the south of the sun in autumn.
Impact of Predation Risk on Emergence by Little Brown Bats,Myotis lucifugus(Chiroptera: Vespertilionidae), from a Maternity Colony
Authors: Kalcounis Matina C. , Brigham R. Mark
Published: May 2010

When bats emerge from their roosts in the evening to forage and drink, it appears as though their departure involves brief periods when many individuals emerge interspersed with periods during which few individuals emerge. Clustering is seen in many species of animals and probably has an anti‐predator or information‐transfer function. Regardless of its function, clustering in the emergence of bats may intensify as a result of large numbers of individuals trying to pass through a small exit hole in a short period of time.

A total of 31 observations of emergence were made from May to Aug. 1992 and 1993 at a maternity colony of little brown bats (Myotis lucifugus), in Cypress Hills, Saskatchewan, Canada. To determine the effects of a predator on clustering in the emergence, a plastic great horned owl (Bubo virginianus) was used as a predator model and mounted close to roost exits on 8 nights. Recorded calls of a great horned owl were played back towards the roost. The predator model and associated calls did not affect the number of bats that emerged, the median time of emergence, or the degree of clustering in the emergence. There was a significant positive relationship between the extent of clustering in the emergence and the number of bats that emerged. Emergences of more than 25 bats were clustered. Thus, we found no evidence to support clustering during emergence as being an anti‐predator response. However, clustering may be intensified with increased numbers of individuals trying to pass through a narrow space in a short period of time.
Competitive Mate Searching in Thirteen‐lined Ground Squirrels (Mammalia, Sciuridae): Potential Roles of Spatial Memory
Authors: Schwagmeyer P. L.
Published: May 2010

Male thirteen‐lined ground squirrels search actively for spatially scattered females during the mating season, and male mate‐location ability is a key determinant of male mating success. These circumstances are predicted to favour male spatial abilities. I conducted a female‐removal study in which females were observed the day before coming into oestrus and then removed for 2 h on the morning they were sexually receptive; males were scored on the sites they visited while searching for removed females. Two hypotheses were tested: 1. males search preferentially at sites where they had encountered the female the day before (i.e. males remember particular locations used by the female); and 2. male searches are guided by long‐distance chemical cues. The results showed little evidence for male attraction to sites used frequently by the female, where residual chemical cues should have been strongest; moreover, males failed to locate oestrous females that were displaced from their home ranges. Consistent with the spatial‐memory hypothesis, male searches were biased toward sites where they had interacted with the female, suggesting that males are capable of using spatial memory to relocate individual females once they become sexually receptive. In addition, both the order of male site visits and male performance on a maze task indicate a potential role for spatial memory in avoiding recently searched sites.
Arena Headings, Vanishing Bearings and Homing Times by Argogorytes carbonarius (Hymenoptera, Sphecidae) after Displacement in Open or Closed Containers
Authors: Schöne Hermann , Schöne Hedwig , Kühme Wolf‐Dietrich , Kühme Lisa
Published: May 2010

Arena headings, vanishing bearings and homing times were recorded in the digger wasp Argogorytes carbonarius after displacement in ‘open’ or closed (‘box’) containers during two time periods. The periods differed in two ways: 1. wasps were assumed to be inexperienced with the release site during the first period, whereas during the second period they were assumed to be familiar with it; 2. during the first period the arena was open on all sides, during the second it was surrounded by a wall.

All wasps chose arena headings and vanishing bearings in or close to the direction of the sun's azimuth during the first period and there was no difference in homing times between ‘open’ and ‘closed’ wasps. These directions also were chosen by all wasps during the second period in the arena and also by ‘open’ wasps at vanishing. ‘Box’ wasps, however, vanished preferably in the sector of home direction. They also reached home faster than in the first period. The results are discussed with respect to landmark orientation and the path‐integration hypotheses.
Suckling in Free‐ranging Beef Cattle — Temporal Patterning of Suckling Bouts and Effects of Age and Sex
Authors: Lidfors Lena M. , Jensen Per , Algers Bo
Published: May 2010

Suckling was studied in primiparous cross‐bred beef cattle (Bos primigenius f. taurus) kept on a 1000‐ha grazing area. Observations were made at mean calf ages of 1, 7, 65 and 123 d on 20 calves of each age. Recordings of four different behaviours were made at 12‐s intervals and recordings of butting were made continuously during one suckling bout per calf and age. Two types of sucking, occurring within the same suckling bouts, were distinguished: sucking 1 (rhythmic sucking movements) and sucking 2 (<3 sucking movements followed by release of teat). It was found that sucking 1 made up 18.5–35.2 % of the total suckling time. The highest proportion of sucking 1 was recorded at 65 d of age. Sucking 2 made up 39.3–50.0 % of the total suckling time and it tended to decrease with age. The first recording of sucking 1 was made on average 7.3 (±4.4) recordings after start of a suckling bout and continued for about 5 min thereafter. Sucking 2 was recorded both before, during, and after sucking 1 activity, which is here suggested as being the main period of milk intake. Buttings were recorded during the whole suckling bout, but tended to be most frequent towards the end of the sucking 1 period. Calves did not show any regular suckling pattern at 1 d of age, but at 7 d, a distinct pattern had been established. The calves initiated the suckling bouts, with increasing calf age, more often than the mothers. The suckling bouts were mostly terminated by the calves, especially after 7d of age. Suckling bouts were significantly longer in bull calves than in heifer calves at 7d, but sucking 1 was recorded significantly more often in heifer calves at 123 d. From this study, it is suggested that, in cattle, the temporal patterning of the suckling bout appears to consist of three main parts: prestimulation, milk intake, and post‐stimulation.
Age Structure of Parasitized and Unparasitized Populations of the Field Cricket Teleogryllus oceanicus
Authors: Simmons Leigh W. , Zuk Marlene
Published: May 2010

We compared the age structure of three populations of Teleogryllus oceankus that differed with respect to their exposure to parasitization by an acoustically‐orienting parasitoid fly, Ormia ochracea. Within two unparasitized populations, females were, on average, younger than males. Female age did not vary across the three populations but males were younger, on average, in the parasitized population. Sexual differences in age structure within populations may arise due to differential risks associated with pair formation. Because we only know of a single parasitized population from which we can sample, we can not be sure that some other ecological difference does not account for the observed variation in age structure across populations. However, the decreased age of males in the parasitized population is at least consistent with the notion of viability selection on males.
Evidence of Pre‐mating Reproductive Isolation in Two Allopatric Populations of the Vlei Rat, Otomys irroratus
Authors: Pillay N. , Willan K. , Meester J. , Cooke J.
Published: May 2010

Laboratory experiments were undertaken to ascertain whether or not individuals of two allopatric Otomys irroratus populations (Kamberg and Karkloof) distinguish between mates from the same (homotype) and the other (heterotype) population. The study aimed to establish the existence of pre‐mating reproductive isolation mechanisms between the two populations. In both ‘whole‐animal choice’ trials and olfactory discrimination tests, all females significantly preferred homotype stimulus males or odour. Although males of both populations preferred homotype females, males were less discriminating at the start of experiments, possibly because of increased exploratory drive at this time. Furthermore, Kamberg males demonstrated equal preference for both stimulus females during the dark phase of the light cycle; no explanation is given for this phenomenon. Overall, the results indicate the existence of population‐specific courtship behaviour, with olfactory cues apparently playing an important role in mate recognition. It is therefore possible that, should representatives of the two populations meet in nature, they may be reproductively isolated through behavioural means.
Orientation by the Bat Phyllostomus discolor (Phyllostomidae) on the Return Flight to its Resting Place
Authors: Höller Patrik
Published: May 2010

Bats have a well‐developed spatial memory, which enables them to navigate even when the conditions are extremely unfavourable for orientation. However, if they were to adhere too strictly to a flight path planned from memory and independent of exteroceptive control, they would be in danger of colliding with unexpected obstacles. In the experiments described here, Phyllostomus discolor that had familiarized themselves with an octagonal flight arena developed a clear preference for certain resting sites and were able to fly to these sites without recourse to external orientational cues. Proximal and distal cues were ruled out separately, by rotating the direction in which the bats started out within the arena or by rotating the entire arena in the room. Furthermore, by marking the preferred site with a visible identifier it was shown that even when additional aids to orientation are available, the bats do not make use of them. On the other hand, all the bats tested responded immediately to a reduction of the landing area, demonstrating that they are capable of incorporating exteroceptive information into the orientation process in certain circumstances.
Post‐conflict Social Events in Wild Mountain Gorillas (Mammalia, Hominoidea). I. Social Interactions between Opponents
Authors: Watts David P.
Published: May 2010

Researchers have documented elevated rates of affinitive interaction between opponents shortly after aggressive conflicts, or reconciliation, in many primate species. Reconciliation may ameliorate the immediate negative effects of aggression by reducing the chance of further aggression between opponents and thus reducing tension, and may avert or repair damage to long‐term social relationships important to the animals' fitness. Data on post‐conflict interactions between opponents in two groups of wild mountain gorillas(Gorilla gorilla beringei)fail to show reconciliation after conflicts between females, between males, or between immatures, but females seem to commonly reconcile themselves with males after receipt of male aggression. Females and subordinate males often avoid same‐sex opponents after conflicts. Females commonly retaliate against female aggressors, and post‐conflict rates of aggression between females are higher than baseline levels. Females may not need to achieve reconciliation with each other because relationships between co‐resident relatives are resiliant, while those between non‐relatives are mostly neutral to antagonistic. Males are, however, important social partners and protectors of females, and female transfer is common. Thus, the results strongly support the ‘important relationships’ hypothesis for the function of reconciliation.
Post‐conflict Social Events in Wild Mountain Gorillas. II. Redirection, Side Direction, and Consolation
Authors: Watts David P.
Published: May 2010

Inevitably, members of primate groups sometimes have aggressive contests with each other. Targets of aggression can engage in several types of interaction with third parties to ameliorate its adverse effects. They can redirect aggression, which may reduce the risk of further aggression from the initial opponents and reduce tension, or they can initiate affinitive interactions with third parties, in order to seek protection or reassurance. They can also receive reassuring acts from them (‘consolation’). Researchers have documented high levels of redirection in many primate species, but consolation is thus far known only in chimpanzees. Data on post‐conflict social interactions between targets of aggression and third parties in two groups of wild mountain gorillas(Gorilla gorilla beringei)show that immatures and subordinate males, but not females, redirect aggression at high rates. Furthermore, immatures seek affinitive interactions with their mothers, and adult females seek them with adult males, at elevated rates. Affinitive interactions between females and males seem mainly to have a protective function and are associated with decreased risks of further aggression between female opponents. Redirection by females after female‐female conflicts may be uncommon because targets commonly retaliate against aggressors. Males may offer females protection and consolation as services, and the results support the argument that such services are important when dominance relationships between females are often undecided and retaliation between opponents is common.
A New Quantitative Technique for Categorizing Whistles Using Simulated Signals and Whistles from Captive Bottlenose Dolphins (Delphinidae,Tursiops truncatus)
Authors: McCowan Brenda
Published: May 2010

A widespread problem in the study of animal vocalizations is evaluating the acoustic similarity of signals both between individuals of a social group and between social groups. This problem becomes especially salient when classifying the narrow‐band frequency‐modulated signals, such as whistles, found in many avian and mammalian species. Whistles are usually characterized by their relative change in frequency over time, known as whistle ‘contour’. Measuring such a characteristic is difficult as it is not a single measurement, such as the mean frequency or duration of a signal, but several associated measurements of frequency across time. This paper reports on a new quantitative technique for determining whistle types based on whistle contour similarity and an application of this technique to the whistles of bottlenose dolphins to demonstrate its utility. This ‘contour similarity’ technique (CS technique) uses cluster analysis to group the correlation coefficients of frequency measurements from a data set of signals. To demonstrate the efficacy of this CS technique, three data sets were analysed, two using computer‐generated signals and a third using adult bottlenose dolphin whistles, to (1) examine the efficacy of correlation coefficients for grouping signals by their similarity in whistle contour and (2) determine the viability of this technique for categorizing bottlenose dolphin whistles. Measured actual frequencies and correlation matrices from the four simulated signal types and a correlation matrix from the whistles of five captive adult bottlenose dolphins were each subjected to K‐means cluster analysis and the resulting signal types were evaluated. Results indicated that the technique grouped actual frequencies according to the amount of shared actual frequencies and grouped correlation coefficients successfully according to signal contour. This result endured even if contours differed in overall duration or actual frequency or were expanded or compressed with respect to frequency or time. The results suggest that this approach is a viable method for assigning whistle contours to categories in bottlenose dolphins or any other species with narrow‐band, frequency‐modulated signals.