bluuebunny/crossref_metadata_2025 huggingface dataset:
Broodcare or Egg Cannibalism by Parents and Helpers in Neolamprologus brichardi (Poll 1986) (Pisces: Cichlidae): a Study on Behavioural Mechanisms
Authors: von Siemens Michael
Published: May 2010

In the cichlid species N. brichardi the young are tended by parent animals and broodcare helpers. No qualitative differences in the care are apparent. The regulation of eggcare by nonreproductive helpers is of especial interest as it excludes an endogenous component found in the parental care of other cichlids, based on sex and the reproductive cycle.

The importance of the factors dominance, territory, size (age) experience, model and the continuous presence of eggs for helper eggcare disposition was examined experimentally. It was shown that subdominant inexperienced young fish will clean clutches, whereas dominants feed on them. Subdominant eggcleaners can be transformed into dominant eggfeeders; the change can be delayed or prevented by the continuous presence of eggs. Subdominant fish in a territory are more inclined to clean clutches than those in an aggregation. With growing experience (or size) helpers orient broodcare behaviour increasingly by a dominant model. Dominance and experience play no part however in broodpairs; here there are sex‐dependent differences. In both sexes, eggcaring behaviour can be evoked only at the beginning of a breeding cycle. The disposition is bolstered by the presence of the clutch, and wanes after egg removal in females faster than in males. The tendency to continue eggcare can be strongly extended in both sexes by the continuous presence of eggs. Comparison with other cave‐breeding cichlids showed that parental eggcare in these and N. brichardi was similarly regulated. Helper broodcare, however, is very differently regulated. These differences are discussed, as well as possible conclusions on the influence of endogenous and exogenous regulatory factors.
Social Organization of Cataglyphis cursor Ant Colonies (Hymenoptera, Formicidae): Inter‐, and Intraspecific Comparisons
Authors: Retana Javier , Cerdá Xim
Published: May 2010

The social organization of several colonies of the ant Cataglyphis cursor with different compositions has been studied by means of individual marking of workers and later treatment of data with correspondence analysis. There are always three main poles or groups of tasks: inactivity, unspecific tasks in the nest and outside activities. From them, three groups of workers are separated: inactives, which stay immobile in the nest a great part of their time; interiors, which perform various tasks in the nest; and foragers, that are engaged in activities outside the nest. Several factors, such as the presence of the queen, the colony size or the season of the year influence the social structure of C. cursor colonies and originate important inter‐, and intracolonial variations.
The Effects of Male Dominance, Secondary Sexual Characteristics and Female Mate Choice on the Mating Success of Male Atlantic Salmon Salmo salar
Authors: Järvi Torbjörn
Published: May 2010

The reproductive behaviour of male and female Salmo salar was studied in a specially constructed arena.

The Results showed that body size, cardiac‐somatic index and relative kype size were all correlated with male dominance rank. Dominant males approached ripe females more frequently and ultimately mated more frequently than subordinates. Males repelled by females from the spawning beds had smaller adipose fins. No correlation was found between female aggression and male dominance, body size or cardiac‐somatic index. The results suggest that male salmon establish a dominance hierarchy during the spawning period and that intra‐sexual selection has favoured the evolution of a status signalling system, whereby males signal their dominance rank by their relative kype size. Dominant males having conspicuous secondary sexual characteristics are able to mate more frequently because they can occupy ripe females. As females seem to select their mates on grounds of the relative size of the adipose fin, inter‐sexual selection is also presumed to have affected the evolution of male secondary sexual characteristics.
A Cue‐Isolation Experiment to Determine if Caspian Tern Parents Learn Their Offspring's Down Color
Authors: Shugart Gary W.
Published: May 2010

A ground‐nesting gull or tern (Laridae) parent will attack a foreign conspecific chick that is substituted for the parent's chick at about the time the parent's chick is mobile. Presumably, parents discriminate among chicks using some combination of vocal, morphologic, and behavior cues. It is not known which cues are used. Morphologic variation in chicks' down potentially provides discrimination cues in some species of Laridae, such as the Caspian tern (Sterna caspia). To test discrimination based on the down color of chicks, a parent's chick was replaced sequentially with foreign conspecific chicks that were similar and dissimilar to the down color of the parent's chick. This cue‐isolation experiment indicated that parents rejected dissimilar chicks more frequently. Thus, parents learn the down color of their chicks and then use this information as a basis for aggressive rejection of foreign chicks. A recognition system based on morphology allows parents to detect and reject foreign chicks with a probability greater than chance.
Vocalization during Agonistic Behaviour in Cottus gobio L. (Cottidae): An Acoustic Threat Display
Authors: Ladich Friedrich
Published: May 2010

Agonistic behaviour in the river bullhead C. gobio consists of visual (raising gill covers and fins, lowering the head, darkening) and acoustic (single knock sounds and trains of knock sounds) threat displays, rarely followed by attacks and bites. This study investigates the relationship of vocalizations with size, dominance, territory dimensions and sex of the opponents. Four groups, each consisting of a big male, a small male and a female, were each investigated for three different days. The number of won contests of each individual, the numbers of each sound produced during these encounters and the tank part where encounters took place were determined.

Subordinate fish emit fewer sounds but relatively far more trains of knock sounds than dominant ones. They produce relatively more sounds under shelters whereas dominants do this on uncovered areas. α‐fish produce more calls during agonistic encounters with β‐fish than Ω fish. In β‐individuals no such difference was noted. Basically no sex related behaviour could be observed. In each area of the tank one individual won most contests (= territory). Dimensions of territories differed significantly between individuals in each tank (α‐, β‐, Ω‐fish). In no case were all three individuals able to maintain territories.

Relative sizes of fish correlate significantly with relative numbers of successful encounters and with territory dimensions. Furthermore, both parameters are positively correlated with the numbers of sounds emitted by an individual.

Sound production in C. gobio functions as an acoustical threat display. Because of the high energy costs of sound emission underwater it might be a very effective method of assessing the fighting ability of an opponent.
Do Females Turn Males on and off in Barnacle Goose Social Display?
Authors: Hausberger Martine , Black Jeffrey M.
Published: May 2010

Male barnacle goose Branta leucopsis display duration is longest when females respond with loud repetitious calls, intermediate when females follow silently and shortest when females call softly. We argue that these encouraging and discouraging vocalizations and the associated posturing is an influential behaviour used during the mate choice, pair maintenance and aggressive interaction processes.
Determinants of Variation in Antipredator Behavior of Territorial Male Threespine Stickleback in the Wild
Authors: Foster Susan , Ploch Stephen
Published: May 2010

Although antipredator behavior of threespine stickleback has been extensively studied in the laboratory, interactions between stickleback and their predators in nature have never been described. This paper describes interactions between territorial male stickleback and four predators on males or on the young they guard. Two of the predators, cutthroat trout and a hemipteran nymph (Belostomatidae), prey on males but not on young. Another, the roughskin newt, is a potential predator of young but does not pose a threat to males. Prickly sculpin prey both on the males and on offspring that males guard. Differences in behavior toward the four predators indicate that males are capable of rapid discrimination among predators and the threats they pose. Males also discriminate among size classes of sculpin that present different predation risks, but not among size classes of trout large enough to pose a threat. The difference in response to these predators probably reflects the difference in risk to offspring and the amount of time each predator typically stays in the territory of a male. Trout pass through rapidly, whereas sculpin, which are ambush predators, can remain within a territory for a long period of time if not chased out. The presence of young in the nest had no apparent effect on the response of males to these predators. This could, however, be due to a masking effect of uncontrolled variation in natural encounters. Responses to newts were similar to those directed toward sculpin too small to attack the male. They involved rapid chases and bites, often directed at the head, a part of the body that was typically avoided in encounters with larger sculpin. Males watch and avoid the belostomatid nymphs, but do not attack them.
Variable Parental Care in a Labrid Fish: How Care Might Evolve
Authors: Berghe Eric P. van den
Published: May 2010

Hypotheses for the evolution of parental care suggest several intermediate stages between no care and full care. To shed light on how care might evolve, I describe intermediate stages within one species. These include spawning behavior ranging from out‐of‐nest spawning, (which involves no parental care) to algal nests and associated male parental care (plus intermediate stages between the two previous categories), all observed in the same individual males of the peacock wrasse, Symphodus tinca. About 20% of males go through transitional stages from no care to full care as the season progresses. These stages are: 1) following females over large areas, 2) focusing on an area about 10 × 10 m, 3) chasing other fish, (both con‐ and heterospecific) from this area, 4) focusing spawns into a 1–2 m2 area that he modifies by adding algae, and 5) remaining with the site day and night until the eggs hatch and the young disperse. This sequence of stages is similar to the evolutionary sequence suggested by previous theory, but differs in that site limitation is not necessary in order to lead to site attachment.
Brood Size, Male Fanning Effort and the Energetics of a Nonshareable Parental Investment in Bluegill Sunfish, Lepomis macrochirus (Teleostei: Centrarchidae)
Authors: Coleman Ronald M. , Fischer Robert U.
Published: May 2010

We present a model and an experimental test for a nonshareable parental‐investment behavior (fanning of eggs) using parental male bluegill sunfish. The model predicts that as brood size increases, nonshareable investment into the brood should increase if a parent is to maximize its remaining lifetime reproductive success. The experimental test manipulated the number of eggs in nests and quantified the frequency and tempo of fanning in the field using underwater video equipment. As predicted, male bluegill fanned larger broods more frequently than smaller broods. The fanning tempo (beats per min) did not change with changes in brood size. Parental males lost substantial amounts of body weight during the period of parental care, and lipid extractions revealed a loss in nonpolar lipids. The difference in fanning frequency between large and small broods did not result in differential weight loss for the parents, but parents that fanned more tended to lose more nonpolar lipids from the body tissue than males that fanned less.
Flexibility of Wild Chimpanzee Nut‐cracking Behavior Using Stone Hammers and Anvils: an Experimental Analysis
Authors: Sakura Osamu , Matsuzawa Tetsuro
Published: May 2010

Nut‐cracking behavior in wild chimpanzees (Pan troglodytes verus) using natural stone hammers and anvils was studied through transect survey and experimental analysis at Bossu, Guinea. Transect surveys revealed that hammers were significantly smaller than anvils, although the role division was not strict. Analysis of experiments such as separating nuts and stones found under palm trees revealed the chimbanzees' flexibility in tool use. The behavioral patterns of transportation, discrimination, and the substitution of tools were not stereotyped. This flexibility appears to stem from the chimpanzees' understanding of the relationship between tools and referents, i.e. the function of tools.
Sex Differences in Mate Choice in a Monogamous Biparental Fish, the Midas Cichlid (Cichlasoma citrinellum)
Authors: Rogers William , Barlow George W.
Published: May 2010

The Midas cichlid is strongly monogamous and requires biparental care in the wild to raise any young to independence. We predicted that male and female Midas cichlids would select mates with qualities correlating with good parental caretaking ability. Adults were given choices of prospective mates varying systematically in one of three qualities: size, aggressiveness and reproductive experience. The subject expressed its choice, if any, by the amount of courtship shown to the various alternatives. Females selected large males over small ones, aggressive males over unaggressive ones and experienced males over inexperienced ones. Large, aggressive and experienced males should enhance the likelihood of brood survival. In contrast, males showed no consistent choice among females of any level of the three variables. This lack of consistent choice by the males, coupled with earlier findings of greater overall parental investment by females, indicates that the breeding system in the Midas cichlid is driven by female choice and that males either may not have the option of being selective or may not benefit from choosing.
Song Switching in Mate Attraction and Territory Defense by Western Meadowlarks (Sturnella neglecta)
Authors: Horn Andrew G. , Falls J. Bruce
Published: May 2010

Many passerines have a repertoire of song types that appear to be functionally equivalent. Previous work suggested that in such species the act of switching between song types in itself might be a territorial signal, a sexual signal, or both. If switches are frequent enough, they may also serve to advertise a male's repertoire size, which is thought to signal male quality. We studied variation in song switching by western meadowlarks through the season and during interactions with conspecifics. Males repeat each song, to form a bout, before switching to the next song type. Males repeat each song type fewer times during mate attraction and when their female goes out of sight. They also switch song types at the onset of two types of territorial interactions and sexual interactions. Thus song switches are apparently used in both mate attraction and territory defense. However, males switch through their entire repertoire only in certain situations. At other times, the timing of a male's song switches, and what songs he sings, might be more important than repertoire size itself in determining his success in intra‐ and intersexual interactions.
Behavioural Castes, Dominance and Division of Labour in a Primitively Eusocial Wasp
Authors: Chandrashekara K. , Gadagkar Raghavendra
Published: May 2010

Female wasps of the primitively eusocial species Ropalidia marginata may be classified, by a statistical analysis of their time‐activity budgets, into three behavioural castes namely Sitters, Fighters and Foragers. We show that Foragers are primarily responsible for the risky task of foraging for food and have very poorly developed ovaries. Sitters and Fighters forage rarely if at all but share the bulk of the intra‐nidal tasks such as feeding larvae and building the nest. Both Sitters and Fighters have better developed ovaries than Foragers. Queens of most colonies belong to the Sitter caste. There are no obvious morphological differences between queens and workers or between the behavioural castes. Queens are not necessarily the most dominant individuals in their colonies. Instead, most dominance behaviour is performed by a group of workers (the Fighters). Division of labour and social organization are achieved through behavioural caste differentiation and not, as in many other species studied, through a dominance hierarchy led by a despotic queen suppressing all her nestmates into worker roles. This suggests that behaviour patterns in such primitively eusocial insects are likely to be moulded by a complex interaction between selection at the individual and colony levels.
Age Polyethism for Hive Duties in Honey Bees — Illusion or Reality?
Authors: Seeley Thomas D. , Kolmes Steven A.
Published: May 2010

Recently Seeley (1982) claimed that bees working inside the hive exhibit three age castes: cell cleaning, brood care, and food storage. In a subsequent paper, Kolmes (1985) stated that “honey bees do not appear to pass through a temporal sequence of tasks while performing hive duties” and that previous findings of this age polyethism are due to subjective interpretations of data. Here we report new behavioral data and statistical analyses substantiating the claim that age polyethism exists in bees working inside the hive. We followed a cohort of bees until they were 15 days old; they underwent two behavioral transitions. The first took place when the bees were approximately 3–4 d old and was associated with a switch from cell cleaning to other activities, mainly in the broodnest. The second occurred when the bees were approximately 10–12 d old and was associated with a switch from brood care to food‐storage activities and foraging. Thus we present strong statistical evidence of a cell‐cleaning age caste and a brood‐care age caste for bees, but further evidence is needed to demonstrate fully that bees also pass through a distinct food‐storage age caste before starting to work outside the hive. In addition, we demonstrate that Kolmes‘s previous denial of age polyethism in hive workers was caused neither by unusual behavior of his bees nor by weakness of his Kolmogorov‐Smirnov statistical test, but by sampling errors due to a small but critical flaw in his method of labelling bees.
Chemosensory Kin‐communication Systems and Kin Recognition in Honey Bees
Authors: Getz Wayne M. , Page Robert E.
Published: May 2010

Organisms use chemicals to communicate various kinds of information. Here we discuss chemical‐information systems that permit organisms either to identify other organisms as particular individuals or to be classified as a member of a particular kinship group. The material is presented from an integrated‐systems perspective, a level of analysis that has been neglected in the study of kin‐communication systems. After presenting a number of general concepts, we use honey bees as an exemplar for discussing encoding and decoding aspects of chemical recognition in the context of kin discrimination. We present new results on the variability of the cuticular signature in honey bee workers.
Density‐dependent Extra‐pair Copulations in the Swallow Hirundo rustica
Authors: Møller Anders Pape
Published: May 2010

Density‐dependence of extra‐pair copulation rates and mate guarding intensity in the monogamous swallow Hirundo rustica was studied from 1983 to 1988 in N. Jutland, Denmark. Changes in local population size paralleled changes in national population size from 1976 to 1988. Median and mean colony size increased and minimum, mean and median nearest neighbour distance decreased with increasing population density. The percentage of female swallows involved in extra‐pair copulations increased significantly with increasing population density between years and with increasing colony size within years in spite of the fact that male mate guarding intensity changed similarly. Mate guarding did reduce the probability of the female being involved in extra‐pair copulations, but not to the extent that it compensated for the density‐dependent increase in extra‐pair copulation attempt rates. Natural and sexual selection arising from extra‐pair copulations is frequency‐dependent and varies spatially and temporally in relation to population density.
Ultrasonic Vocalizations of Six Taxa of Southern African Gerbils (Rodentia: Gerbillinae)
Authors: Dempster Edith R. , Perrin M. R.
Published: May 2010

Ultrasonic calling during male‐female encounters between individuals of the same species was investigated in six taxa of southern African gerbils, namely Tatera brantsii, Gerbillurus paeba paeba, G. p. cxilis, G. tytonis, G. setzeri, and G. vallinus. Vocalizations were detected by means of a bat detector utilizing a superheterodyne signal converter and a countdown circuit. Signals were recorded at audible frequencies and analysed with a sonograph.

All taxa vocalized at ultrasonic frequencies by means of strongly modulated frequency “sweep” calls, which differed among taxa in duration, maximum and minimum frequency. “Clicks” were emitted by G. p. paeba and G. p. exilis, and G. tytonis emitted a “stutter” vocalization which consisted of a series of clicks. Long modulated “whistles” were identified from G. vallinus and T. brantsii at lower frequencies than “sweep” calls. Only one call type, a “sweep” call which differed in duration and frequency from all other taxa, was identified in G. setzeri.

Cluster analysis was applied to the data using 7 acoustic characters. G. p. paeba and G. p. exilis displayed the highest similarity level between taxa and differed only in frequency of “sweep” vocalizations. G. paeba, G. tytonis and G. setzeri formed one cluster, while G. vallinus and T. brantsii formed a separate cluster.

Numbers of calls in interspecific encounters were non‐significantly less than in intraspecific encounters in all taxa except G. p. paeba, in which more vocalizations were recorded in inter‐ than intraspecific encounters. It is not clear whether species discrimination, measured by numbers of vocalizations in interspecific encounters, occurs.
Exposure of Dunnocks (Prunella modularis) to their Previous Wintering Site Modifies Autumnal Activity Pattern: Evidence for Site Recognition?
Authors: Schwabl Hubert , Gwinner Eberhard , Benvenuti Silvano , Ioalè Paolo
Published: May 2010

We caught dunnocks at a wintering site near Pisa/Italy prior to their departure for breeding territories and held them indoors north of this site (Andechs/Germany) on a simulated photoperiod of 52.5 °N. After birds had gone through a reproductive cycle and postnuptial moult they developed migratory restlessness in autumn. At this time one group was transferred back to the previous wintering site (Pisa) where birds were held in individual activity cages in an outdoor aviary, allowing them to perceive as much environmental information as possible. A second group was transferred to a control site near Tour du Valat/France of approximately the same latitude and climate, but different longitude and held in an identical aviary. The diurnal activity pattern changed after transfer back to the previous wintering site, but not after transfer to the control site. Specifically, the amount of morning activity was reduced while afternoon activity was increased. This effect was restricted to those individuals that had been developing nocturnal migratory restlessness the previous spring. It was absent in individuals without migratory restlessness in spring, indicating that the different patterns were not due to unspecific effects from the testing sites. These results are consistent with the hypothesis that birds were able to derive information about their locality and to recognize their previous wintering site, resulting in suppression of migratory state by experience. The results are not definitely conclusive, however, because of several difficulties in the interpretation of perch‐hopping activity, which are discussed in detail.
Eco‐ethological Study on Raiding Behaviour of the European Amazon Ant, Polyergus rufescens Latr. (Hymenoptera: Formicidae)
Authors: Mori Alessandra , Grasso Donato Antonio , Le Moli Francesco
Published: May 2010

In this paper we report the results of a detailed study on the behavioural ecology of slave raiding in the European amazon ant, Polyergus rufescens Latr. The field study, supported also by a video‐tape recording technique, was conducted over an unbroken period of 53 days, during which observations of the activity of the residents (both slave‐makers and slaves) were made for 10 h each day. It was possible to observe 38 slave raids distributed over 32 days, among which 27 were followed by the sack of 10 different nests of Formica cunicularia Latr., whereas 11 failed because of various reasons. Simple, compound and multiple raids occurred. We recorded the timing, frequency, distance, and direction of slave raids, including the number of participants and the type of captured brood. Moreover, particular attention was paid to the atmospheric conditions present at the moment of the raid onset. Information was also collected about the behaviour of the “activators” and the scouts before and during the movement of the storming column. Both dealate and winged P. rufescens queens, having emerged from the mixed colony during 6 sexual flights, were seen following the outbound raiding column during 4 raids. Finally, some peculiar behaviour, such as digging out the soil near the target nest to facilitate the entry of the raiding swarm, and the pillage of adult ants (eudulosis) was recorded and described. Data have been compared with what is known about the other species of the genus Polyergus.
Resource‐defense Polygyny and Male Territory Quality in the New Zealand Fur Seal
Authors: Carey Peter W.
Published: May 2010

The polygynous New Zealand fur seal, Arctocephalus forsteri, breeds in densely‐packed colonies with males defending exclusive territories. The distribution of individuals within a colony of these seals was monitored over three consecutive breeding seasons and behavioural thermoregulation was found to be an important factor influencing the site selection of both males and females. Shaded areas and pools of water were used by both sexes for cooling and use of these cooling substrates increased as rock surface temperature increased, resulting in a clumped distribution on hot days. Substrate preferences were tested experimentally by manipulating the availability of cooling substrates during two seasons. The number of females using an area increased significantly after shade or pools of water were added to that area. For males, pool additions resulted in increased use of those areas, while adding shade had no effect. Cooling substrates had a patchy distribution and could therefore be monopolised by territorial males. Using the number of females on a territory as a measure of male mating success, it was found that female numbers were most strongly positively correlated with the area of shaded substrate on a territory. Total territory area was also positively correlated with number of females. It is argued that thermoregulatory constraints are a major factor affecting female site choice, and that this in turn affects male mating success.
Persistent Intercolonial Trunkroute‐marking in the African Weaver Ant Oecophylla longinoda Latreille (Hymenoptera, Formicidae): Tom Thumb's versus Ariadne's Orienting Strategies
Authors: Dejean Alain , Beugnon Guy
Published: May 2010

The territorial African weaver ant Oecophylla longinoda forages in a 3‐dimensional system when attending honeydew secreted by coccid colonies. The orienting strategy allowing workers to reach a static food resource was studied in laboratory conditions. Contrary to other studies devoted to territoriality in O. longinoda, our experiments show that, when moving off the nest, territorial faecal marking by the major workers is not randomly placed all over the home‐range area. The chemical trail leading from the nest to a given food site is reinforced by faecal materials both on the horizontal and the vertical planes. In addition to visual cues and chemical trails laid by the major workers (Holldobler & Wilson 1978), foragers use the territorial marking both to localize the food site and to come back to the nest. Thus, anal‐drop deposition in O. longinoda also has a clear dual‐purpose function: territorial and orientationai marking. The ecological value of such a discrete Tom Thumb's orienting strategy enables workers to quickly reach a food location even after more than 5 months of inactivity on this given site. The persistent marked trail also has an intercolonial effect. This could allow the keeping of exploitation of a definite food site by alien colonies of the same species by reducing time costs for new exploring phases or for learning new spatial cues when foraging on an unknown environment.
Mate Choice for Non‐siblings in Wild House Mice: Evidence from a Choice Test and a Reproductive Test
Authors: Krackow Sven , Matuschak Bernhard
Published: May 2010

Two experiments were designed to test whether wild house mice discriminate between olfactory cues from different kin and, if so, whether given preferences would relate to actual reproductive decisions. Experimental animals were mice born to the offspring of wild‐caught house mice. Litter‐mates stayed together until 60 d of age and were then housed individually. In a choice test, animals were placed in the middle of an arena with 4 openings which led to small cages containing bedding material from opposite‐sex animals of known kinship (full‐sib, cousin, unrelated) or clean material. Test animals (11 oestrous females, 11 males tested with oestrous females' bedding, 8 males tested with material from non‐oestrous females) preferred conspecific to control bedding. Males tested with oestrous females' bedding significantly preferred unrelated to full‐sib odours. In a second experiment, 34 males were each mated simultaneously to 3 females (sister, cousin, unrelated) and these groups were then housed together for 5, 10, and 15 d. Females were checked for litters during the next 20 d. Reproductive rate increased significantly in the 15 d cohabitation group, and significantly more cousin and unrelated females than sisters gave birth to a litter.
Recognition of Individual Males' Songs by Female Dunnocks: a Mechanism Increasing the Number of Copulatory Partners and Reproductive Success
Authors: Wiley R. Haven , Hatchwell B. J. , Davies N. B.
Published: May 2010

Previous studies have shown that a female dunnock Prunella modularis increases her reproductive success on average by copulating with more than one male resident on her territory and thereby obtaining extra help in raising offspring. Here we document behavior by females that affects which males copulate with them. During her period of receptivity to copulation, a female in a territory shared by two males often left the dominant (or alpha) male, which guarded her most of the time, and approached the subordinate (or beta) male when he sang. A female's responses to individual males thus tend to increase her own reproductive success by increasing her chances for copulation with both males sharing her territory. Playbacks of tape‐recorded songs in the field showed that females approached only songs of resident males, not neighbors. They can therefore discriminate individual males by their songs alone, a capability not previously established for female songbirds. Despite intensive guarding of females by males, mating success among male dunnocks depends in part on female choice.
Song Learning in Zebra Finches Exposed to a Series of Tutors during the Sensitive Phase
Authors: Slater P. J. B. , Richards C. , Mann N. I.
Published: May 2010

Young male zebra finches exposed to a series of adult males during their sensitive phase for song learning tended to learn from several of them, in contrast to those exposed to two or more tutors simultaneously. There is a tendency to learn more from later tutors, either because the memory of their elements over‐writes that of earlier ones or because sensitivity is greater at this stage. No clear relation could be found between features of the song or behaviour of tutors and whether or not they were copied. In common with earlier studies, tutor song output, beyond a certain minimum was found to be unimportant.
Egg Mimics in Haplochromine Cichlids (Pisces, Perciformes) from Lake Victoria
Authors: Goldschmidt Tijs
Published: May 2010

An ecomorphological explanation is given of the anal spots of haplochromine cichlids from Lake Victoria. Anal spots are ovoid orange‐yellow spots on the anal fins of these fishes. The possible roles of sexual selection and predation as determinants of the form of these spots are discussed. Evidence is given that the anal spots are egg mimics and thus examples of intra‐specific mimicry. Mimicking an egg to stimulate sexually active females presumably is an important demand on the form of the anal spots. However, no positive correlation was found between anal spot size and egg size. Light intensities of the habitat of the species investigated showed a negative correlation with anal spot size. In contrast to this, egg size did not show a negative correlation with light intensities. It is suggested that, besides mimicry, at least one more demand is involved in determining spot size: that of being conspicuous. Conspicuousness is likely to have a positive impact (benefits) on courting conspecific females, but a negative one (costs) with regard to predators who hunt visually for either adults or eggs. The actual appearance of anal spots may be a compromise. This may explain the mismatch between egg size and spot size in many species. Qualitative evidence is presented that predation pressures on adult haplochromines exerted by visually hunting predators are relatively high in lighter habitats, viz. near the rocks and near the surface. An alternative hypothesis that spots in dark surroundings cannot be seen unless they are supra‐normal is discussed.
Innate Flower Recognition in Bumblebees (Bombus terrestris, B. lucorum; Apidae): Optical Signals from Stamens as Landing Reaction Releasers
Authors: Lunau Klaus
Published: May 2010

Innate behavioural reactions in bumblebees were observed in flower dummy experiments. In a previous paper, it was shown that the approach of flower‐naive, untrained bumblebees toward flower dummies is released by colour signals, i.e. a gradient of spectral purity. The bumblebees are directed toward that part of a flower dummy which exhibits the highest spectral purity (Lunau 1990). In the present work it is shown that the bumblebees, while still in flight, make contact with this part using their antennal tips. The antennae reaction is followed by a landing reaction which is released by olfactory and optical signals. The specific optical signals of the guide area which release the landing reaction were investigated. Since in the flower dummies which were used, the guide had the highest spectral purity, most of the antennae reactions were executed at the guide. The antennae reaction allows for a precise orientation and may involve the stimulation of a specialized area of ommatidia. Minute changes in optical guide parameters could thus be detected. The following features of stamens which most effectively released the landing reaction were: a minimum of 2 theca dummies; an oval shape of theca dummies which face each other along the longitudinal axis (both these characteristics are found in genuine stamens); 4 mm distance between theca dummies (this coincides with the distance between the antennal tips of bumblebees); two equally sized theca dummies each with an area of 7 mm2 (this size of theca dummies was preferred over larger or smaller ones; the latter parameter was not changed when the corolla size was varied). Colour parameters are not involved in releasing the landing reaction. Clearly, bumblebees possess an innate releasing mechanism (IRM) that responds to optical signals of anthers which release the landing reaction. The experimental results are in accordance with conclusions drawn from the comparative studies of Osche (1979, 1983a, 1983b) that many flower guides can be interpreted as stamen mimics. Therefore stamens as well as stamen mimics represent a highly standardized signal for the insect pollinators and they are well suited for innate orientation at flowers.
Male Mate Choice in Mixed Bisexual/Unisexual Breeding Complexes of Poecilia (Teleostei: Poeciliidae)
Authors: Schlupp Ingo , Parzefall Jakob , Schartl Manfred
Published: May 2010

The livebearing all‐female fish Poecilia formosa reproduces by gynogenesis, a modified form of parthenogenesis. P. formosa forms at least two breeding complexes: in its northern range it exists sympatrically with Poecilia latipinna and in its southern range with Poecilia mexicana. Differences between these complexes and their possible origin are discussed. Embryogenesis is triggered by sperm of males of these closely related sympatric species. Because inheritance is strictly maternal, from the male point of view energy and time invested are totally lost.

In this study we wanted to elucidate whether males are able to distinguish between conspecific and parasitic females. It could be shown that males are able to distinguish females optically, but that this ability was obscured as soon as chemical and/or tactile contact was possible.

Furthermore, we found that females in an attractive phase of their sexual cycle are always preferred, regardless of species. This is possibly the mechanism by which parasitic females obtain the matings they need to reproduce.
Parental Investment and Territorial/Sexual Behavior in Male and Female Reed Warblers: Are they Mutually Exclusive?
Authors: Dittami .John , Hoi Herbert , Sageder Gabriele
Published: May 2010

The behavioral and endocrine changes from prenesting to feeding phases of reproduction were examined in free‐living reed warblers. Apart from the onset of feeding behavior, these changes in males are particularly evident in song, territorial behavior and circulating levels of testosterone. The interactions between an individual's physiology and behavior during these behavioral transitions were tested first by correlating song and feeding rates with circulating levels of testosterone and secondly by implanting feeding males with steroids and documenting the resulting effects on song, territoriality and parental behavior. The physiological mechanisms associated with the transition from the sexual phase (nest‐building and egg‐laying) to the parental (incubation and feeding) in females were also examined. In this case, estrogens were implanted during the parental phase to enhance sexual behavior. The results demonstrate an antagonistic relationship between sexual/territorial behavior and parental care in males which is mediated by changes in circulating androgens and no such antagonism in females. The effects of parental manipulation on the feeding rates of the partners and the growth rates of offspring have been examined to shed light on the necessity for male parental input.
Clicks and Communication: The Behavioural and Social Contexts of Hector's Dolphin Vocalizations
Authors: Dawson Stephen M.
Published: May 2010

Hector's dolphins (Cephalorhynchus hectori) have a simple vocal repertoire, consisting almost entirely of ultrasonic clicks. They produce no whistles, and very few audible sounds. To examine acoustic communication in this species I analysed the relationship between click types and behaviour. The proportion of complex click types was greater in large groups, suggesting that these sounds have social significance. Clicks having 2 peaks in their time envelope and two frequency peaks were strongly associated with behaviours indicative of feeding. High pulse rate sounds, in which the repetition rate of ultrasonic clicks was audible as a “cry”, were most strongly associated with aerial behaviours. These data suggest that echo‐location is not the sole function of Hector's dolphin clicks, and that echo‐location and communication are likely to be closely linked. I hypothesize that dolphins may have the ability to gather information from the echoes of each other's sonar pulses. This may reduce the need for a large number of vocal signals, and may explain the apparent simplicity of the acoustic repertoires of some odontocetes.
Male Mating Success in the Mountain Dusky Salamander, Desmognathus ochrophaeus: Are Small, Young, Inexperienced Males at a Disadvantage?
Authors: Verrell Paul A.
Published: May 2010

Young, small, sexually‐inexperienced males suffer lower mating success than older, larger, more experienced males in many species of animals. I compared the mating success of male Desmognathus ochrophaeus (Amphibia: Caudata: Plethodontidae) reared to maturity in the laboratory with that of males collected as adults in the field. Courtship trials were staged in the laboratory between single males and females. Laboratory‐reared males were significantly smaller in body size than adult males collected in the field, were certainly inexperienced sexually and were probably younger. No difference was found between laboratory‐reared males and field‐collected males in any measure of mating success, although the former apparently produced smaller sperm masses. I conclude that newly‐mature male D. ochrophaeus are not discriminated against by females in the context of mate choice, and do not need to “rehearse” courtship in order to obtain successful inseminations. However, newly‐mature males are probably at a disadvantage in terms of aggressive and sperm competition with larger males.
Interspecific Mate Choice Following Cross‐fostering in a Mixed Colony of Greylag Geese (Anser anser) and Canada Geese (Branta canadensis). A Study on Development and Persistence of Species Preferences1
Authors: Fabricius Eric
Published: May 2010

The role of early experience in mate choice and species preference of geese was studied in an experiment where young greylag geese (Anser anser) were cross‐fostered by Canada geese (Branta canadensis). In two successive years, all eggs from 9 nests of wild Canada geese were removed and replaced by greylag goose eggs. The young greylag geese then followed their Canada goose foster parents on their southward migration in autumn, to return with them in spring. Of 35 returning birds, all 16 females paired with greylag goose males (100%) whereas of 19 males 5 paired with Canada goose females (14%) and the remaining 14 with greylag goose females (74%).

The pair bonds generally persisted as long as both birds were present, but after loss of a partner, the remaining bird usually re‐mated. Even when this happened several times during the lifetime of a male, the new mate was always a Canada goose female, showing that the males were sexually imprinted to this species. The Canada goose females which had mated with the greylag ganders also remated when widowed, but their new mate could be either a Canada goose or a greylag goose.
Food Scrounging and Diffusion of Foraging Skills in Pigeons, Columba livia: The Importance of Tutor and Observer Rewards
Authors: Giraldeau Luc‐Alain , Templeton Jennifer J.
Published: May 2010

Naive feral pigeons (Columba livia) adopt novel foraging skills after watching tutors demonstrating them. Despite this ability, novel foraging skills do not always spread within pigeon flocks. Two factors are important in determining whether skills will spread or not. 1) Tutor reward: naive observers fail to acquire a novel skill if the tutor is not rewarded for its demonstration. 2) Scrounging: observers also fail to acquire the skill when they obtain rewards from the tutor's demonstrations (i.e. when they scrounge). We examine jointly the relative importance of tutor reward and of scrounging in promoting the diffusion of skills. Moreover, we investigate how magnitude of scrounger reward could affect the diffusion of skills. In Experiment 1 we found that scrounging had a stronger effect than tutor reward, but that the performance of observers was inhibited most strongly when tutors obtained no reward and observers scrounged. In Experiment 2 we found that the magnitude of scrounger reward had no effect on observers' acquisition of skills when tutors were rewarded. These results, taken with those of earlier work, suggest that variables such as tutor reward and scrounging, as well as task complexity and density of tutors in groups, are important factors affecting skill diffusion within groups.
The Consequences for Communication of Call Overlap in the Tungara Frog, a Neotropical Anuran with a Frequency‐modulated Call
Authors: Schwartz Joshua J. , Rand A. Stanley
Published: May 2010

We presented male tungara frogs,Physalaemus pustulosus, with call‐triggered computer‐synthesized whines that either did or did not overlap the frogs' own frequency‐modulated whines in time. When the stimulus was nonoverlapping, males added a high proportion of chuck notes to their calls. When the stimulus was overlapping, males responded with either no or only small increases in chucking. This suggests they have difficulty detecting whines while vocalizing. When female tungara frogs were given a choice between alternating whines and out‐of‐phase overlapping whines they did not discriminate. The result with males was similar to that previously obtained with species of frogs that have amplitude‐modulated advertisement calls (Schwartz1987a), the result with females was different. We discuss our findings in relation to peripheral processing of spectral and temporal information in the anuran auditory system.
Of Ducklings and Turing Machines: Interactive Playbacks Enhance Subsequent Responsiveness to Conspecific Calls
Authors: Evans Christopher S.
Published: May 2010

Distress calls of mallard ducklings consist of a highly stereotyped series of notes. When two ducklings are simultaneously separated from the brood, they characteristically call in alternation. Each bird inhibits its calls while the other is vocalizing, thus preventing masking and facilitating localization by the hen. I examined whether exposure of ducklings to calls presented in a naturalistic alternating pattern affected subsequent responsiveness to them. Individual ducklings were exposed to either 40 s or 80 s of computer‐controlled distress call playbacks, using an algorithm that mimicked the behavior of another duckling. Calls were presented only when the subject was silent and ended as soon as it began to vocalize. Each of these ducklings was paired with a ‘yoked’ control. Birds in these control groups experienced exactly the same pattern of playbacks as the ‘interactive’ birds, but the stimuli had no consistent relationship to their own vocal behavior. When the same calls were played back 24 h later, in a fixed pattern that was independent of the ducklings' behavior, birds that had received 80 s of prior interactive exposure were significantly more responsive than both their yoked controls and birds receiving only 40 s of such playbacks. This result suggests that interactive vocal experience, characteristic of natural communication, affects the subsequent perceptual sensitivity of ducklings.