bluuebunny/crossref_metadata_2025 huggingface dataset:
Host–parasite coevolution: genetic variation in a virus population and the interaction with a host gene
Authors: WILFERT L. , JIGGINS F. M.
Published: May 2010

Host–parasite coevolution is considered to be an important factor in maintaining genetic variation in resistance to pathogens. Drosophila melanogaster is naturally infected by the sigma virus, a vertically transmitted and host‐specific pathogen. In fly populations, there is a large amount of genetic variation in the transmission rate from parent to offspring, much of which is caused by major‐effect resistance polymorphisms. We have found that there are similarly high levels of genetic variation in the rate of paternal transmission among 95 different isolates of the virus as in the host. However, when we examined a transmission‐blocking gene in the host, we found that it was effective across virus isolates. Therefore, the high levels of genetic variation observed in this system do not appear to be maintained because of coevolution resulting from interactions between this host gene and parasite genes.
How Do Carpenter Bees Recognize the Entrance of their Nests?: An Experimental Investigation in a Natural Habitat1
Authors: Anzenberger Gustl
Published: May 2010

Carpenter bee females (genus Xylocopa) enter only their own nests. They can be found in the same burrow over a period of months, regardless of whether they arc living singly or aggregated in close vicinity. The aim of this study was to investigate and to clarify which sensory systems are responsible for the recognition of the nest. Females of three different African species were tested in their natural habitat. Following alteration in the immediate visual surroundings of either the entrance or the entire dwelling stem, bees behaved as they did in undisturbed situations and entered their nests. Furthermore, a relative dislocation of the entrance within the dwelling stem or a displacement of the whole stem within a restricted range had no effect on the recognition of the burrow. When the entrance was plugged by foam rubber the bees landed only after extended searching. When the entrance was closed by a strip of scotch tape the bees searched for several minutes, departed, then returned and searched again with the same result. The bees showed no indications that they recognized their burrow. These results strongly support the conclusion that the bees recognized their burrows primarily or exclusively by olfactory cues, and, furthermore, that individual odors were involved. The possible contributions of different sensory systems for the recognition of the nest and the possible biological function of the use of olfactory cues are discussed.
The Ontogeny of Display Behaviour in Sceloporus undulatus: (Sauria: Iguanidae)
Authors: Roggenbuck Madeleine E. , Jenssen Thomas A.
Published: May 2010

A longitudinal study (from neonate to adult) was made of the display behaviour of 36 fence lizards from 8 clutches. A frame‐by‐frame analysis of 941 video‐taped displays revealed that the hatchlings possessed almost all of their adult display patterns by the first two days of life. Of the total variance in the display behaviour, 7% or less was attributed to experience. Of the variance among lizards, approximately half came from between clutches and half from between clutchmates. Our data indicate that the visual communication signals (head bob displays) of this vertebrate species are almost totally innate.
Acoustic Features Used in Song Discrimination by the Veery
Authors: Weary Daniel M. , Lemon Robert E. , Date Elizabeth M.
Published: May 2010

To investigate which song features are used for discrimination by the veery (Catharus fuscescens), we synthesized songs by computer and manipulated or deleted various features. These songs were then played to territorial males in their natural habitat. Differences in response to these stimuli indicated the relative importance of the manipulated song components. We found that certain features must be maintained in order to elicit a territorial response similar to that elicited by the natural song. These features were the frequency changes between and within syllables, the dominant higher frequency band (or voice), the intra‐syllable syntax, and the rapid repetitive amplitude and frequency modulations. Manipulations of inter‐syllable syntax independent of frequency changes between syllables, broad changes in amplitude, and the lower frequency band, did not have a significant effect on response. We thus concluded that they are not essential as cues for discrimination or species identification. Re‐recordings of songs broadcast along transects indicate that song components used in encoding species identity are those which transmit well across veery territories.
Rearing Conditions Affect Chemosensory Preferences in Young Cichlid Fish
Authors: Barnett Colin
Published: May 2010

Offspring of the Midas cichlid, Cichlasoma citrinellum, reared with both parents showed a chemosensory preference for their mother over their father on the first day of free‐swimming and no clear preference for either parent thereafter. Fry reared in isolation preferred their mother; this preference appeared slightly stronger and longer‐lasting in fry reared with only their mother. The preference was reversed in fry reared with only their father.
Clutch Defence in Great Tit (Parus major) Pairs and the Concorde Fallacy
Authors: Windt W. , Curio E.
Published: May 2010

We conducted an experiment to test whether great tits (Parus major) base their decisions of clutch defence on past investment or future benefits. Results were obtained by manipulation of future benefits. Great tit pairs of an experimental group with reduced clutch‐size and thus diminished benefits defended their offspring against a live raptor significantly less than a comparable, non‐manipulated control group with the same amount of past investment (clutch‐size, incubation stage, time of year). While in the females the difference between the two groups was obvious from the beginning of a trial, the difference in the males developed only during the course of a trial, suggesting that the male bases its response on the female's response deficit. A more onerous explanation of the female signaling the male the egg loss by using a language‐like symbol is not supported by the data. The experiment thereby permits the conclusion that at least the great tit female avoids committing the Concorde fallacy in the strict sense.
Group Size in Foraging African Penguins (Spheniscus demersus)
Authors: Wilson Rory P. , Wilson Marie‐Pierre T. , McQuaid Leslie
Published: May 2010

Diving synchrony was examined for varying group sizes of African penguins (Spheniscus demersus) travelling to their foraging grounds from their breeding islands. Groups of fewer than 12 birds always dived synchronously, whereas groups of more than 17 birds always dived asynchronously. Since travelling penguins do not dive deeply, large groups of birds can remain together irrespective of diving synchronization. Observations from boats showed that foraging penguins rarely occurred in groups of more than 17 birds. We suggest that groups of penguins that do not have synchronized dives cannot forage effectively, because foraging penguins dive deeply.
Counting Behavior by Rats in a Simulated Natural Environment
Authors: DAVIS HANK , BRADFORD SHEREE ANNE
Published: May 2010

Three experiments were performed to explore the rat's ability to count objects in its environment. Previous research demonstrating counting behavior in animals has typically involved overtraining or extreme motivational conditions in which food or safety were at a premium. In the present experiments, a simulated natural environment was employed in which rats were required to enter a particular tunnel in an array of six to obtain food. Spatial, olfactory and visual cues were controlled so that selection of the correct tunnel was based solely upon the ordinal position of the tunnel. Experiments 1 and 2 demonstrated that this behavior could be learned relatively rapidly and maintained despite change in the spatial configuration of the test area. In Experiment 3, retention of the tunnel entry discrimination was demonstrated following an inactive period of one year as well as six months thereafter. Collectively, these data extend the range of situations in which rats have performed numerical discriminations, and suggest that the environmental support necessary to demonstrate such abilities may include relatively natural test situations, rather than the use of extreme motivational states induced under arbitrary environments.
Pair Swimming and Mutual Partner Guarding in Monogamous Butterflyfish (Pisces, Chaetodontidae): a Joint Advertisement for Territory
Authors: FRICKE HANS W.
Published: May 2010

The ecology and social systems of Red Sea butterflyfish were studied along the Sinai coast. Distribution, population density and sociography indicate a preponderance of monogamy in all species, independent of reef zonation and seasonal or long‐term changes of the reef environment. The social and mating systems are mutual monogamy; partners remain together for up to 6 years. Links between the monogamy and benthic habits of these fish are indicated by their feeding ecology and by a comparison with Indopacific plankton‐feeding species, which usually occur in groups. Territories are defended pairwise. Pair partners nearly always remain within visual contact, but a species‐typical distance apart. Pair swimming is independent of season or time of day. Experimental partner removals led to speedy replacement of mates. Possible causes of high partner permanency with little partner fidelity are discussed. In good habitats, single territorial adults do not occur. They would be unable to defend and maintain a territory over long periods. While cooperating in defence and maintenance of a territory, each individual can exploit the resources of the territory including availability of a mate. Pair swimming with mutual partner guarding is considered a joint territorial advertisement similar to duetting in birds; it minimizes agonistic interactions between territory holders. As butterflyfish have planktonic larvae without any broodcare, monogamy could not have evolved in response to broodcare activities as in many other vertebrate groups.
Confusion of Phonotaxis by Masking Sounds in the Bushcricket Conocephalus brevipennis (Tettigoniidae: Conocephalinae)
Authors: BAILEY WINSTON J. , MORRIS GLENN K.
Published: May 2010

Female Conocephalus brevipennis, executing phonotaxis to the call of a conspecific male broadcast from a speaker, were subjected to varying levels of background sound so as to progressively mask the attracting signal. The background consisted of either random noise or the call of a sympatric congener, C. nigropleurum and was delivered from above the orienting female. Disruption of phonotaxis was assayed by monitoring the angular dispersion of the female's exit path from the arena, relative to the position of the conspecific call. Random noise significantly interfered with phonotaxis when it was within 2 dB of the conspecific call intensity, both signals measured at the centre of the arena. The equivalent effect of the call C. nigropleurum was 5 dB above conspecific call intensity. The implication of signal loss within background noise is discussed as are the possible interactive behaviours of competing sympatric syntopic species.
A Polygamous Social System of the Fan‐tailed Warbler Cisticola juncidis
Authors: UEDA KEISUKE
Published: May 2010

The social system of an individually‐marked population of the fan‐tailed warbler Cisticola juncidis was studied in Japan, over six breeding seasons from 1978 to 1983. More than 127 males established territories, some 50–70% were polygynists each year. Territorial males were replaced frequently within seasons. Females were less faithful than males to their first breeding sites. Perennial or seasonal pair bonds were rare, maintained over two successive breeding attempts, by only 13.6% of females. Half the females left the area after one breeding attempt. Frequent divorce, rapid and multiple remating of females, multiple breedings, and female movement over a wide area all combine to skew breeding sex ratio from unity and favor polygyny.
Feeding and Avoiding Predation Hazard: the Behavioral Response of the Prey
Authors: FRASER DOUGLAS F. , HUNTINGFORD FELICITY A.
Published: May 2010

A forager may respond to the hazard of predation by (1) ignoring the hazard and eating maximally at all levels of food (risk‐reckless); (2) avoiding the hazard and minimizing eating (risk‐avoiding); (3) reducing feeding by the same amount at each level of food, making greater reductions as hazard increases (risk‐adjusting); (4) reducing feeding at low levels of food, while accepting a greater hazard when food levels are high (risk‐balancing). We experimentally distinguished these four nominal responses using 9 three‐spined sticklebacks, Gasterosteus aculeatus in a 3 times 4 factorial, repeated measures design. The fish were tested in an aquarium containing a refuge inaccessible to predatory trout, Salmo trutta, in 12 combinations of food (low, medium, high) and predation hazard (predator density = 0, 1, 2, 3). With predators, sticklebacks ate less and used the refuge more. Amount eaten, but not time spent out of the refuge, was positively correlated with food, even in the absence of predators. Since sticklebacks as a group appeared to depress feeding by equal amounts at all levels of food, they employed a risk‐adjusting response. However, individuals varied in their response to hazard.
Sexual Differences in the Responses of Captive Great Reed Warblers (Acrocephalus arundinaceus) to Variation in Song Structure and Repertoire Size
Authors: CATCHPOLE CLIVE , LEISLER BERND , DITTAMI JOHN
Published: May 2010

The function and evolution of repertoires in songbirds is still not clearly understood. This study involves the great reed warbler Acrocephalus arundinaceus and playback of recorded song to both captive males and females under controlled laboratory conditions. Females were implanted with oestradiol and the copulation solicitation display used as an index of sexual response. Males were not implanted and crest‐raising used as an index of aggressive response. Two types of songs were used (short and long) and two sizes of repertoire (high and low). Females only responded to long songs, and responded significantly more to high than low repertoires. It was concluded that long songs have a sexual function and that high repertoires are the result of intersexual selection through female choice. Males responded to short and long songs, but did not discriminate between high and low repertoires. Adding a live male to the experiment made no difference to female responses but males responded significantly more. When field studies are also taken into consideration the overall conclusion is that song quality and repertoire size is particularly important in female choice, and that short songs and a male presence are more important in aggressive behaviour. Integration of both field and laboratory studies on males and females should lead to more rigorous testing of hypotheses concerning the function and evolution of bird songs.
In Pursuit of Females: Following and Contest Behavior by Males of a Namib Desert Tenebrionid Beetle, Physadesmia globosa
Authors: Marden James H.
Published: May 2010

Male Physadesmia globosa beetles spend much of their active time following females, searching for single females, or contesting with other males for position behind females. Once paired with a female, a male does not feed, can seldom stay paired for more than a few min, and can mate only if the female stops moving. Females rarely stop moving unless they find a large food item, or burrow into the sand and become inactive. Thus, males expend great effort positioning themselves for opportunities to mate, which seldom arise. However, males do not display any alternative mating strategies, and none appear to be available, for females are scarce in relation to males, and do not become receptive to mating at any predictable times or places.
Nutrient Dynamics of a Swarm‐founding Social Wasp Species, Polybia occidentalis (Hymenoptera: Vespidae)
Authors: Hunt James H. , Jeanne Robert L. , Baker Irene , Grogan Donald E.
Published: May 2010

The kinds, rates of acquisition, inter‐individual transfers, and intra‐colonial movements of nutrients were ascertained for the advanced eusocial paper wasp Polybia occidentalis (Olivier). Foraging worker wasps (“foragers”) bring arthropod prey and nutritive liquids (“nectar”) to the nest, and these are usually transferred to nest workers (“receivers”) on the outer nest envelope. Arthropod prey items, which are brought intact to the nest, are malaxated by one or more receivers before being fed to larvae; malaxating adults retain a portion of the hemolymph for their own nourishment. Nectar is usually transferred (via adult‐adult torphallaxis) from foragers to receivers on the nest envelope; some nectar is given to larvae, and all adults that imbibe it retain at least some for their own nourishment. Larval saliva of P. occidentalis contains glucose, protein, and free amino acids and so is highly nutritive; the nutrient content of the saliva closely resembles that of the saliva of other social wasp taxa. Adult wasps imbibe larval saliva, but very little is apparently transferred by those adults (via trophallaxis) to nestmates. Brood cannibalism was infrequent during this study. Adult worker and male wasps possess chymotrypsin‐like and trypsin‐like enzyme in their midguts and so are likely capable of protein digestion. The midgut proteases show an age‐correlated variation in concentration. Pulp foragers are significantly smaller and lighter in weight than are receivers.
Early Learning and the Recognition of Conspecific Cocoons by Carpenter Ants (Camponotus spp.)
Authors: Carlin Norman F. , Halpern Robert , Hölldobler Bert , Schwartz Peter
Published: May 2010

Groups of newly‐eclosed workers of two carpenter ant species (Camponotus floridanus and C. tortuganus) were reared in the presence of conspecific cocoons, cocoons of the other species, or were kept without cocoons. Groups of older workers (> 20 days), previously exposed to conspecific brood in their natal nest, were familiarized with either conspecific or heterospecific cocoons. After 14 days of exposure, groups were subjected to short‐term (5 min) and long‐term (10 day) preference tests. Young and older workers retrieved and retained many cocoons of both species, familiar and unfamiliar. However, a pattern of non‐exclusive discrimination emerged: (1) Young workers exposed to conspecific cocoons picked up and retrieved conspecifics before unfamiliar heterospecifics, and retained conspecifics longer. (2) Young workers generally required experience with conspecifics to develop this preference, as those exposed to only heterospecifics and those deprived of cocoons were impartial in short‐term tests. However, in long‐term tests (5–10 days), naive young workers significantly preferred unfamiliar conspecifics. (3) Older workers preferred conspecific cocoons, whether familiar or unfamiliar, in short‐term tests, but their tolerance for heterospecifics in the longer term (5 days) could be increased by recent familiarization. In no case did young or older ants significantly prefer familiar heterospecifics to conspecifics. These results confirm a role for early learning in brood recognition by carpenter ants, but suggest that it is less important than in Formica species studied by previous authors.
The Comparative Ethology of Courtship in Salamandrid Salamanders. 1. Salamandra and Chioglossa
Authors: ARNOLD STEVAN J.
Published: May 2010

This paper describes for the first time spermatophore deposition and sperm transfer in the salamander genus Chioglossa. As in Salamandra, the Chioglossa male holds the female in ventral amplexus and deposits his spermatophore under the female's vent. The female drops down upon the spermatophore to accomplish sperm transfer. This mode of sperm transfer is unique to the salamandrid genera Salamandra and Chioglossa and is at least 26 million years old. These two genera also share a number of derived features of preliminary courtship.
Sex Differences in the Play Behavior of Yearling Yellow‐bellied Marmots
Authors: JAMIESON SCOTT H. , ARMITAGE KENNETH B.
Published: May 2010

Play in yearling yellow‐bellied marmots (Marmota flaviventris) was studied under non‐manipulative field conditions in the Upper East River Valley of Colorado. The behavior patterns constituting play were described and illustrated and 12 specific hypotheses related to sex differences were tested. The results of these tests were used to evaluate the adaptive significance of play by comparing two major functional hypotheses: motor training and social cohesion.
The Development of the Star Compass in Garden Warblers, Sylvia borin
Authors: WILTSCHKO WOLFGANG , DAUM PETRA , FERGENBAUER‐KIMMEL ANGELIKA , WILTSCHKO ROSWITHA
Published: May 2010

To test whether celestial rotation or the geomagnetic field served as reference system for the calibration of the star compass, young garden warblers were handraised under the following conditions:

In series I, two groups of birds were raised under an artificial sky the center of which lay in 360° N. For one group, the sky rotated around its center (1 rotation per day), while for the other the sky was stationary. In series II, three groups were raised under a rotating sky with the center of rotation in different position with respect to magnetic north.

Tested under a stationary sky in the absence of meaningful magnetic information, only the birds that had experienced the rotating sky were oriented in series I; their tendency away from the former center of rotation corresponded to their natural southerly migratory direction.—In series II all birds, irrespective of the former relationship between rotation and magnetic north, showed directional preferences away from the former center of rotation.

Our findings demonstrate the crucial role of celestial rotation in the establishment of the star compass. During the first summer there seems to be no transfer of information from the magnetic field to the stars. Thus celestial rotation and the magnetic field serve as independent reference systems for the genetically encoded migratory direction.
Invasion of Nests ofLasioglossum imitatumby a Social Parasite,Paralictus asteris(Hymenoptera: Halictidae)
Authors: Wcislo Williamx T.
Published: May 2010

Paralictus asterisMitchell is a socially parasitic sweat bee that invades nests and becomes the dominant reproductive in colonies of a phylogenetically related host,Lasioglossum (Dialictus) imitatum(Smith). The parasite has a greatly enlarged quadrate head, with elongate scythe‐like mandibles, and other morphological modifications apparently associated with a parasitic lifestyle. Nevertheless, the parasite did not forcefully enter nests. Host guards adopted a defensive posture at the nest entrance when they contacted a dead, frozen parasite, suggesting that they recognized the intruders as parasites. Living parasites, however, only sometimes induced this guarding response, while in other cases parasites entered host nests without obvious signs of aggression from the guard. Guards also responded aggressively to both frozen and living conspecifics from other nests, but were not aggressive to living or frozen nest‐resident conspecifics, suggesting that the cues used for recognition of both unrelated conspecifics and parasites are chemical ones. More than one parasite can invade and occupy a nest, and successful invasion was not influenced by whether a parasitic female was mated or had developed ovaries.
Patterns of Urination of a Blind Subterranean Rodent, Spalax ehrenbergi
Authors: Heth Giora , Todrank Josephine
Published: May 2010

Urination patterns of blind mole rats of the Spalax ehrenbergi superspecies of Israel were investigated in the laboratory under various conditions in various types of simulated tunnel systems. Behavioral responses to urine in these systems were observed. The results suggest that mole rats do not mark their tunnels or novel areas, either along the tunnel floor by dropping a urine‐trail or at the peripheral ends of the tunnel systems. Urination is not a fear response, and the urine does not contain a chemosensory releaser. Intruders respond (e.g. by sniffing, running away, aggressive threat displays etc.) to occupant's urine in a previously occupied system, and some occupants urinate at a border in ‘no‐contact’ encounters with a potential intruder. Male and female mole rats seem to use urine to advertise their ownership of resources by placing their sanitation areas in the vicinity of the nest and food store and may advertise their identity and occupancy at borders when there is potential contact with intruders. Likely similarities between urination patterns in the laboratory and in nature are discussed.
Social Organization in the Guest‐ant Formicoxenus provancheri
Authors: Errard Christine , Fresneau Dominique , Heinze Jürgen , Francoeur André , Lenoir Alain
Published: May 2010

The results of an investigation on the division of labour in the guest‐ant Formicoxenus provancheri, conducted by observing colonies containing individually marked adults, are presented. Five colories of Formicoxenus were installed in the laboratory with their hosts, Myrmica incompleta, in order to document, over 10 d, the location of individuals as well as individual and interactive types of behaviour. The results show that each colony of Formicoxenus consists of three groups: a group of nurses who remain in the Formicoxenus nest (some 21% of the colony's members); a group of scouts who spend most of their time in the external area (18%) and a very large group of individuals specialized in licking (‘shampooing’) the host to obtain regurgitations (61%), who essentially remain in the Myrmica nest. Division of labour in Formicoxenus appears to be a special adaptation to the xenobiotic way of life. The apparent link between social structure and the probability of profiting from trophallactic exchanges with the host species could lead to interesting predictions on the division of labour in other guest‐ants.
Effects of Temporal Sampling Patterns of All‐occurrence Recording in Behavioural Studies: Many Short Sampling Periods Are Better than a Few Long Ones
Authors: Zinner Dietmar , Hindahl Jutta , Schwibbe Michael
Published: May 2010

All‐occurrence recording is generally thought to yield unbiased results. However, its accuracy and power to detect real effects may depend on the temporal patterning of the observation periods. Although several studies evaluated the suitability of time‐sampling methods (one‐zero and instantaneous sampling), there has not been an evaluation of various temporal patterns of the ‘all‐occurrence’ method to date. Here we present an empirical comparison of time‐sampling and all‐occurrence recording methods, based on a large data set, with special reference to various temporal patterns of all‐occurrence recording. The three different sampling methods were imposed on raw data protocols. The scores, obtained by the use of each method and temporal pattern, were compared with true values from the corresponding continuous video recordings. The accuracy and power of each method was estimated by comparison of medians and magnitudes of effect (rm), respectively. We were able to confirm results of earlier studies on the suitability of time‐sampling methods (one‐zero and instantaneous sampling), but we found that different temporal patterns of all‐occurrence sampling yielded magnitudes of effect that differed from true value magnitudes. We conclude that behavioural studies may reveal different results, even when all conditions are the same, only because of power differences of different temporal pattern of the observation periods, for example 1 × 15 min versus 15 × 1 min. Recommendations are made about appropriate application of methods.
Sperm Storage in the Yellow Dung Fly Scathophaga stercoraria: Identifying the Sperm of Competing Males in Separate Female Spermathecae
Authors: Otronen Merja , Reguera Piedad , Ward Paul I.
Published: May 2010

We examined the effects of male and female behaviour and morphology on the process of sperm storage in the yellow dung fly Scathophaga (Scatophaga) stercoraria. The larger of two males was more successful in transferring sperm to females' spermathecae the greater the difference in weight to his smaller competitor, as expected from previous studies by other authors. Sperm length, which is not correlated to body size, affected sperm access to the spermathecae, the female storage organs; longer sperm were more likely to be found in the spermathecae. A female typically had a singlet spermatheca and two spermathecae arranged as a pair, a doublet. However, there was variation from this pattern, which influenced the pattern of sperm storage. We measured the proportion of sperm from two competing males in females' singlet and doublet spermathecae. When the larger male's sperm were longer than his competitor's, they were more often in a female's singlet when he was her first mate and equally likely to be in the singlet or doublet when he was her second mate. When the larger male's sperm were shorter than his competitor's, the pattern was more complicated, principally because his sperm were not as successful at entering the female's doublet when he was her second mate. Counts of sperm, made using the same experimental procedure, showed that these effects were due to greater numbers of sperm entering the females' doublets when the larger male mated second. Sperm length was thus the factor with the largest single influence on the pattern of sperm storage. However, our most important result is that it was the interactions between male and female characters that were significant. Males mostly determine the early, especially precopulatory, events and females strongly influence the later ones.
Homing Experiments in the Tree‐climbing Crab Sesarma leptosoma (Decapoda, Grapsidae)
Authors: Cannicci Stefano , Ruwa Renison K. , Vannini Marco
Published: May 2010

Sesarma leptosoma an East African mangrove‐dwelling crab, migrates twice a day from a system of known dens among the roots to well‐defined feeding areas in the branches of trees, reaching 15 m high. Field experiments were performed to test whether chemical or visual cues are involved in the orientation and homing of this species to reach their feeding areas. Manipulation of the substratum at branch junctions, in order to alter possible chemical cues, did not affect homing ability in S. leptosoma. Moreover, crabs trained to cross an asymmetrical artificial wooden fork could still follow their preferred directions after (1) the fork branches had been switched, (2) the whole fork had been rotated around the trunk, resulting in a right‐left inversion, and (3) the inversion of two wide black and white screens hiding most of the canopy from view of the climbing crabs. These results suggest that S. leptosoma may not rely on reference systems such as chemical trail‐following and chemical or visual cues from the substratum, but probably depend on complex visual information from the surroundings trunks and/or from the sun's position integrated with junction sequence memory.
Mate Switching in a Non‐monogamous Species? The Case of the Common Quail(Coturnix coturnix)
Authors: Rodrigo‐Rueda Francisco J. , Rodriguez‐Teijeiro Jose D. , Puigerver Manuel , Gallego Secundino
Published: May 2010

We investigated the occutrence of mate switching in the common quail, a non‐monogamous species with a temporal pair bond but without either male parental care or territoriality. The study was carried out throughout the breeding seasons of 1993–95 in Mas Esplugues (Catalonia, Spain) by monitoring 28 radio‐tagged couples and 17 radio‐tagged unpaired males. Agonistic interactions between males inside funnel traps containing a female were also recorded. Mate switching within the laying period occurred in 72% of the females, and new partners always had a higher body condition index than old partners. Agonistic interactions inside the funnel traps also showed that successful males had a better body condition index than losers. These results, along with the observed mate‐guarding behaviour of females by their partners throughout the laying period, a highly male‐biased sex ratio (five males per female), the lack of territoriality of males and the expected difficulties which unmated males experience in finding pairs, suggest that mate switching is not induced by paired males. Moreover, the constant inflow of new males observed throughout the fertile period of the female and the low costs stemming from mate change strongly support the idea that it is paired females who induce mate switching, in order to improve their fitness by mating with the best quality male available at every moment of their fertile period.
Threat Sensitivity in Bicolor Damselfish: Effects of Sociality and Body Size
Authors: Helfman Gene S. , Winkelman Dana L.
Published: May 2010

Threat sensitivity involves graded antipredator responses that reflect the degree of predatory threat encountered. Models of predatory Atlantic trumpetfish (Aulostomus maculatus) were presented to differently sized juvenile bicolor damselfish (Pomacentrus partitus) that occurred singly or in small groups to test for threat sensitivity. Bicolor damselfish displayed threat sensitivity by responding more strongly: 1. To large models than to small models; and 2. As models were brought closer. Solitary damselfish showed stronger responses than did fish in small groups. However, no habituation to threat occurred, no correlation was found between response strength and fish size, and many individuals gave strong, ungraded responses to predator models. Comparisons between juvenile bicolor damselfish and threespot damselfish suggest that bicolor are weakly threat sensitive in that they respond strongly regardless of threat (hypersensitivity). Solitary fish are more hypersensitive than grouped fish. Threespot damselfish show a stronger influence of damselfish body size: small threespot exhibit graded responses in proportion to degree of threat (pure threat sensitivity), whereas large threespot show relatively weak responses (nonchalance). These interspecific comparisons indicate the potential range that characterizes threat sensitivity and the possible influence of social and ontogenetic factors on that range.
Aggregation in a Desert Tenebrionid Beetle: A Cost/Benefit Analysis
Authors: Rasa O. Anne E.
Published: May 2010

Parastizopus armaticeps (Coleoptera: Tenebrionidae), a nocturnal fossorial detritivore inhabiting southern Kalahari dunes, aggregates in burrows during the day. Group size increases during drought but 25% of beetles are still found alone or in pairs. During drought, beetles from large groups leave burrows after sunset synchronously and carlier than pairs and single animals and earlier than beetles of any group size after rain. Detritus from the beetles' major foodplant is scarce and food competition high. Beetles emerging early preferentially select and carry high‐quality transportable items into burrows to eat (forage); late‐emerging ones feed on the low‐quality large twigs on the surface. Foraging is shown to be a strategy to secure food items against surface competitors, not one to reduce body water loss during surface exposure. The costs and benefits of group vs. solitary lifestyles and alternate hypotheses for early and synchronous emergence were tested experimentally. Grouped beetles had lower body water loss rates but, due to competition with burrow mates, higher feeding costs than single ones. It is hunger that advances and thus synchronizes emergence time, not social facilitation. Field data support a model predicting that, for maximal benefits, beetles should alternate between solitary and group life at optimal time intervals.
Clark's Nutcracker (Aves: Corvidae) Spatial Memory: Interference Effects on Cache Recovery Performance?
Authors: Bednekoff Peter A. , Kamil Alan C. , Balda Russell P.
Published: May 2010

Clark's nutcrackers,Nucifraga columbiana, accurately v recover thousands of caches per year in the field. Previous experiments have confirmed that these birds possess excellent, long‐lasting spatial‐memory capabilities. We tested whether resistance to interference is one of the features of nutcracker spatial memory. Experiment 1 tested retroactive interference. Nutcrackers showed no decrease in accuracy overall but performed relatively poorly in their final recovery session. Interference is unlikely to have caused these sites to be poorly remembered because they had fewer neighbouring cache sites than better‐remembered sites. Experiment 2 tested for proactive interference. Interference would have caused the experimental birds to be less accurate than control birds. Instead then were slightly more accurate. In experiment 3, nutcrackers were allowed to repeatedly view their cache sites from a cage between caching and recovery. Nutcrackers were less accurate when recovering from cache sites they had viewed. This effect may be due to changes in motivation. Order of caching had no effect on accuracy but nutcrackers were more accurate when recovering caches from central than from peripheral areas of experimental rooms. In summary, these experiments provide further evidence of the remarkable spatial‐memory abilities of Clark's nutcrackers and demonstrate that these birds are highly resistant to interference effects on spatial memory. Comparative tests will be needed to test if specialized food storers are exceptionally resistant to interference in spatial memory.
The Role of Non‐reproductive Helpers in Infant Care in Captive Callithrix jacchus
Authors: Yamamoto Maria Emília , O.Box Hilary
Published: May 2010

Callitrichids have been proposed as communal breeders, with non‐reproductive animals acting as helpers. Reports in the literature attest to the high variability in the behaviour of helpers. The present study assessed four proximate factors involved in helping in captive Callithrix jacchus: age, gender and experience of helpers and composition of their groups. Forty‐eight helpers from 15 families from Natal (Brazil) and Reading (UK) colonies were observed during the first 4 weeks of life of new‐born twins. Infant carrying, transfers and retrieval, and duration of carrying bouts were registered. Results showed that the presence of helpers decreased the costs of infant carrying, with a negatively significant correlation between group size and mean percentage of carrying. Age, but not gender, was a significant factor for infant carrying, transfers and retrieval, and mean duration of carrying bouts, with older helpers contributing more than younger ones. Singletons and oldest non‐reproductive offspring carried infants more, and longer, than twins and offspring with older siblings present in the group. Experience decreased motivation and actual carrying time, but not to a significant level. Age, experience and group composition appeared important factors in the display of infant care by helpers in captive Callithrix jacchus.
Precocious Courtship and Play in Emydid Turtles
Authors: Kramer Matthew , Burghardt Gordon M.
Published: May 2010

In many mammal species, precocious sexual behaviour is a component of play. A recent model for the evolution of play fighting behaviour in muroid rodents by Pellis (1993) proposes that social play in those species has its origin in precocious sexual behaviour. Captive juvenile emydid turtles perform precocious sexual behaviour. After reviewing its occurrence, we focus on detailed observations ofPseudemys nelsoni.Precocious sexual behaviour in these turtles is characterized by the striking ‘titillation’ display, usually observed only when adult males court females. In this display, the digits of the front feet are rapidly vibrated above the eyes of the female. In our observations, both sexes performed the display, which was energetic, spontaneous, and inconclusive (in that sequences of precocious courtship typically ended when either the displayer or recipient stopped and rested, left, or started some other unrelated non‐social behaviour). Displaying individuals clearly preferred conspecific recipients and often appeared to seek out specific individuals. We discuss several plausible explanations for precocious courtship in these turtles but find none entirely satisfying. The characteristics of the precocious courtship behaviour we observed most closely match those commonly listed for social play. Thus, we conclude that the most likely explanation for this behaviour is that it is a component of social play.
The Effects of Zinc Sulphate Anosmia on Homing Pigeons, Columba livia, in a Homing and a Non‐homing Experiment
Authors: Budzynski Cheri A. , Strasser Rosemary , Bingman Verner P.
Published: May 2010

There is debate over whether homing pigeons, Columba livia, use olfactory information as part of their navigational map. Antagonists of the theory argue that homing deficits noted in anosmic pigeons may be due to a non‐specific impairment in general information processing. In Experiment I, we present data from a modest investigation describing the typical navigational deficits that occur following zinc sulphate‐mediated anosmia. Our results are consistent with previous experiments that noted impairments in homing performance from unfamiliar locations of anosmic pigeons. Experiment II is a critical experiment that involved a spatial working memory paradigm; this paradigm consisted of testing zinc sulphate‐treated birds in a forced‐choice alternation task in a T‐maze. This experiment allowed us to determine whether anosmic pigeons were impaired in memory performance, a robust measure of general information processing. There were no differences between the last day of training and a subsequent‐test day when pigeons received an intranasal injection of zinc sulphate. This experiment suggests that zinc sulphate anosmia does not impair general information processing, supporting the hypothesis that homing pigeons use olfactory cues when homing from unfamiliar locations.
Social Behaviour of Individual Oval Squids (Cephalopoda, Teuthoidea, Loliginidae, Sepioteuthis lessoniana) within a Captive School
Authors: Boal Jean Geary , Gonzalez Susan A.
Published: May 2010

The social behaviour of individually identified squids was observed over a period of 4 mo. Squids were reared in captivity and maintained in a shoal of up to 18 animals. Distances between animals averaged 1.6 body lengths, similar to the 1.2 body lengths of wild teleost fish schools. Smaller animals schooled less frequently and were found at the periphery, and familiar and unfamiliar animals shoaled together. Eighty‐six apparent reproductive events were observed. This species of squid, Sepioteuthis lessoniana, is not sexually dimorphic to the human eye and male squids copulated with both males and females but they directed their attention disproportionately towards females. Most copulations occurred more than a month before spawning, lasted only a few seconds and, unlike field observations on spawning grounds, were not followed by mate‐guarding. Two body patterns are described that were used consistently in social interactions by both males and females; these patterns were both associated with reproductive behaviour but their exact function was unclear. A sister species, Sepioteuthis sepioidea, has been described as showing complex social behaviour; in S. lessoniana, no evidence for such behaviour was seen.
LARGE BALLOON PAPILLARY DILATION FOR REMOVAL OF BILE DUCT STONES IN PATIENTS WHO HAVE UNDERGONE A BILLROTH II GASTRECTOMY
Authors: Itoi Takao , Ishii Kentaro , Itokawa Fumihide , Kurihara Toshio , Sofuni Atsushi
Published: May 2010

Extraction of large bile duct stones in patients who have undergone a Billroth II (B‐II) gastrectomy can be challenging. Recently, a large balloon dilation performed after endoscopic sphincterotomy (ESLBD) was useful for the removal of large bile duct stones. The aim of our study was to evaluate the feasibility and safety of ESLBD for removal of bile duct stones in patients who have undergone a B‐II gastrectomy. ESLBD for removal of bile duct stones were performed in 11 patients with a B‐II gastrectomy at Tokyo Medical University Hospital. Immediately after EST, a large balloon catheter (maximum diameter 15 mm, 18 mm, or 20 mm) was passed over the guide‐wire and positioned across the main duodenal papilla. Maximum stone size (short diameter) ranged from 7 to 30 mm with a median of 13.5 mm. The number of stones was 1–26 with a median of 4.8. The common bile duct diameter was 10 mm to 30 mm with a median of 18.1 mm. A mechanical lithotripter for crushing stones was used in two patients (18%). Papillary balloon dilation using variously sized balloons was performed in addition to endoscopic sphincterotomy. Complete clearance of bile duct stones was achieved in all cases at one session. There were no procedure‐related adverse events such as acute pancreatitis or retroperitoneal perforation. ESLBD appears to be an effective and safe treatment for removal of difficult bile duct stones in patients who have undergone a B‐II gastrectomy.
NEEDLE KNIFE SPHINCTEROTOMY FOR AN IMPACTED AMPULLARY STONE WITH DIFFICULT SELECTIVE BILIARY CANNULATION
Authors: Kawakami Hiroshi , Kuwatani Masaki , Onodera Manabu , Haba Shin , Asaka Masahiro
Published: May 2010

Endoscopic treatment is highly effective for extracting common bile duct (CBD) stones and is the most common therapeutic method for CBD stones. For patients with CBD stones, the treatment goal is to completely clear the biliary duct. In general, the successful extraction rate using a basket and/or balloon catheter is as high as 90%. However, stones that are resistant to conventional endoscopic treatment procedures can be both challenging and time‐consuming to treat; and successful treatment can require a combination of techniques, including mechanical lithotripsy or extracorporeal shock‐wave lithotripsy. We performed needle knife sphincterotomy and attempted to remove a CBD stone using biopsy forceps and alligator grasping forceps without a lithotripter in a patient with a large impacted stone at Vater's ampulla. After attempting several techniques, the stone was successfully removed with balloon extraction.
MANAGEMENT OF THE BILE DUCT STONE: CURRENT SITUATION IN JAPAN
Authors: Yasuda Ichiro
Published: May 2010

Endoscopic treatment is now recognized as the standard treatment for common bile duct stones worldwide. Endoscopic treatment routinely involves endoscopic sphincterotomy in most countries including Japan and endoscopic papillary balloon dilation is also a widely used alternative to endoscopic sphincterotomy in Japan. Surgery in any form, including laparoscopic surgery, is mainly performed when endoscopic treatments are unsuccessful or unfavorable. Other therapeutic modalities considered under certain circumstances include lithotripsy under the guidance of percutaneous transhepatic cholangioscopy, peroral cholangioscopy, or enteroscopy; electrohydraulic lithotripsy or laser lithotripsy; and extracorporeal shock‐wave lithotripsy.