bluuebunny/crossref_metadata_2025_split huggingface dataset:
Parental Investment and Division of Labor in the Midas Cichlid (Cichlasoma citrinellum)
Authors: Rogers William 
Published: May 2010

AbstractThe Midas cichlid (Cichlasoma citrinellum) is an aggressive, monogamous fish living in the Great Lakes of Nicaragua. Its breeding success rates are low due to intense competition for breeding sites and high levels of predation on the young.Male Midas cichlids devote a small portion of body weight to gonads and gametes compared with females. Males produce relatively small amounts of sperm perhaps because cichlid fertilization is very efficient and the male has a high certainty of paternity.While pair members invest equal amounts of time in parental care over the course of the breeding cycle, there is a clear division of labor. Males invest more in territorial protection than do females, whereas females provide more nurturance. Both parents are active over the course of the cycle but the male invests more intensely in the early stages of the cycle. About the time the eggs hatch, the burden of care shifts to the female and she continues to invest significantly more than the male over the remainder of the cycle.Females invest much more than do males when tissue investment and parental behavior are combined. Females also assume more of the burden of care as the brood matures. The male is not free to take advantage of this and leave his mate to initiate other broods because two parents are needed to defend the breeding site and brood. Monogamy with biparental care results.
Preflight Signalling in Swans: A Mechanism for Group Cohesion and Flock Formation
Authors: Black Jeffrey M. 
Published: May 2010

AbstractThe preflight behaviour of whooper swans Cygnus cygnus and Bewick's swans Cygnus columbianus bewickii was examined to determine the adaptive significance of the ritual. Analysis of the preflight sequence revealed that the rate of signalling became significantly faster as the time of takeoff approached. This provides the first quantitative evidence that a threshold of excitability is responsible for triggering synchronised flight in social units. Two ultimate and two proximate factors that affect this threshold were uncovered. They are: 1) Maintaining proximity to partners—flight was delayed by birds with non‐attentive mates and signalling lasted on average four times longer than those whose mates showed more interest. 2) Maintaining flock cohesiveness—birds which performed signals for longer periods while swimming among uninterested birds were successful in attracting followers 61% of the time. 3) The bird's feeding performance related to dominance status—less successful feeders (potentially hungry birds), flew after little time and few signals. 4) The type of feeding opportunity at the eventual destination—birds which flew to provided feeds (nutritious barley) spent less time performing preflight signals than when they flew to forage on grass fields.
Song Types and their Use: Developmental Flexibility of the Male Blue‐winged Warbler
Authors: Kroodsma Donald E. 
Published: May 2010

AbstractHow does an animal know the appropriate context in which to use its different vocalizations? I studied this problem with a songbird, the blue‐winged warbler (Vermivora pinus). Mated males in nature tend to sing one song form (II) at dawn, under low light levels, and at a median rate of 15 songs/min. Their other song (I, the more familiar bee‐buzz) is used later in the day, under higher light levels, and at a median rate of 6 songs/min. In the laboratory I tutored different groups of hand‐reared males under normal circumstances (group 1: song II early in the morning, under low light, at a rapid rate; song I later, under high light, at a slow rate), under reversed circumstances (group 2: song I early, low light, rapid rate; etc.), and with no contextual cues (group 3: songs I and II both early and late, under both light levels, and at an intermediate rate). Few males developed entirely normal blue‐wing song, but males of group 2 clearly reversed the use of song forms and components. The relationship between signal form and function in the songs of this warbler appears flexible and to some extent learned by the males.
Social Behaviour of the Carpenter Bee Xylocopa pubescens (Spinola)
Authors: van der Blom Jan , Velthuis Hayo H. W. 
Published: May 2010

AbstractThe development of about 20 relatively small nests of Xylocopa pubescens was studied. After the first offspring had become adult, these nests reached a social stage in which there was only one egg‐layer per nest.Freshly emerged (teneral) adults eat a lot of food, collected by a forager, before they fly out of the nest. This food appears to be of major importance to these bees in that it makes them fully agile. It seems therefore, that part of the food needed for the development of a young bee is not given at the larval stage, via the beebread, but at the teneral adult stage. As a result of this, a necessary overlap of generations is accomplished. Besides, less pollen has to be collected for the provision of a brood cell, so more cells can be constructed within a short period of time.There is a high degree of nest competition. Many nests were taken over by conspecific individuals (or by females of X. sulcatipes) that were searching for nesting sites within the study area. However, although more than 50% of the solitary nests were taken over sooner or later, strangers hardly ever intruded into social nests, with more than one adult. This illustrates how important it is for a reproducing female to tolerate the presence of nestmates which guard the nest in her absence.Although in most cases the foundress of a nest proceeded to produce new brood in the presence of her offspring, it happened that a daughter took over reproduction from her mother. In two of these cases, it could be observed that a mother started a new nest elsewhere after having been thrown out by her own daughter. At least in these cases, nest competition between mother and daughter started long before the mother had reached the end of her reproductive capacities.Since nesting possibilities are scarce, it seems a logical strategy to stay in the maternal nest and wait for a chance to become the egg‐layer if the mother dies or if she loses her dominance.The occurrence of several social interactions among nestmates is discussed:— trophallaxis was observed often, not only under ‘forced’ conditions, but also as a form of ‘voluntary’ feeding;— nestmates were observed to groom each other.
Rhyme‐like Repetitions in Songs of Humpback Whales
Authors: Guinee Linda N. , Payne Katharine B. 
Published: May 2010

AbstractHumpback whales (Megaptera novaeangliae) sing long, complex songs which continually change over time. In certain time periods the songs contain repeating patterns which structurally resemble human rhyming, and which, like human rhyming, tend to occur in highly rhythmical contexts. We speculate that humpback whales may use these repetitions as mnemonic devices, much as humans are thought to use rhymes. With this speculation in mind we examine 548 humpback whale songs from 7 years in the eastern North Pacific and 12 years in the western North Atlantic oceans. We find that rhyme‐like structures are most likely to occur in songs containing the most material to be remembered.
Social Experience and Egg Development in the Parthenogenic Gecko, Lepidodactylus lugubris
Authors: Brown Susan G. , Sakai Toni Jean Y. 
Published: May 2010

AbstractThe present study examined the influence of social experience on egg development in the parthenogenic gecko, Lepidodactylus lugubris. 16 individuals were first housed in communal enclosures. After initial egg development half (N = 8) were removed and placed in isolated conditions. Once isolated individuals laid or miscarried/absorbed their eggs, half of them (N = 4) remained in isolation and the rest were returned to communal cages. Data of inter‐individual distances and behavior were obtained systematically during the study. Dominant animals developed eggs more frequently than subordinate animals, and animals returned to communal cages after isolation developed eggs faster than those that remained in isolation. Pseudocopulations were not observed. The social environment of L. lugubris may be related to egg development in two ways: (1) Greater productivity by dominant individuals may increase not only their personal fitness but also the inclusive fitness of the subordinate individuals; and (2) The presence of other geckos may indicate an environment with the resources necessary to support reproduction and thus facilitate egg development.
Chorusing Behaviour, a Density‐dependent Alternative Mating Strategy in Male Common Toads (Bufo bufo)
Authors: Höglund Jacob , Robertson Jeremy G. M. 
Published: May 2010

AbstractMale chorusing behaviour was studied in a population of common toads (Bufo bufo) on the island of Öland south Sweden, and the functional role of male advertisement calling in this species was experimentally examined. Calling males were larger and heavier than non‐calling males (t = 2.41, p < 0.025 and t = 2.36, p < 0.025, respectively). However, small males were also found to call. This indicates that large males persisted in calling for longer and/or called more often. The proportion of calling males decreased as population size increased during the breeding season, indicating that calling is a low density strategy. Females responded more readily to calls than males. There were insufficient data to determine if the dominant frequencies of advertisement calls were inversely correlated with male body size, however, this relationship was found for the similar release calls. Females were found not to discriminate between high and low frequency calls, but when given a choice between two calls of different sound pressure levels (SPL), females were attracted to the louder calls. Thus, the function of chorusing is to advertise the position of males to mate‐seeking females when the population density is low.
Nuptial Feeding in Insects: Theoretical Models of Male and Female Interests
Authors: Parker G. A. , Simmons L. W. 
Published: May 2010

AbstractWe present a series of prospective models of nuptial feeding, mainly for insects. The models examine various optimal male and female strategies, but do not include any element of mate choice in which the female chooses males in relation to the gift he provides.We find that the female should use the gift to enhance egg size and/or clutch size when gifts represent a relatively large component of the energy resources for the gametes, or when the gift occurs at a relatively late stage in her reproductive cycle. However, if the female receives a single, relatively small gift during her reproductive cycle, she should show a reduced gametic output at the next oviposition. A literature survey revealed several studies that show increases in egg and clutch sizes following gift donation, but we found no instances in which there was a reduction in gametic output. We also find that if gifts are infrequent, there can be significant sexual conflict over the pattern of allocation of donated resources to future offspring. Male interests will generally be best served by a more immediate use of the resources than will be optimal for the female. This may result in selection for male ability to influence vitellogenesis and/or oviposition. Evidence is available which shows that male‐derived substances influence female physiology; this might reflect an outcome towards male interests as a result of an arms race in sexual conflict.Some studies have demonstrated an effect of gift donation on survivorship. We examine models in which gift donation reduces male survival but increases female survival. These suggest that gift donation is most likely to evolve when (1) giving a gift has little effect on male, but a significant effect on female survival, (2) when the male is more likely to father eggs in a later batch, rather than the next batch, and (3) when random mortality is high.
Social Correlates of Variation in Male Calling Behavior in Blanchard's Cricket Frog, Acris crepitans blanchardi
Authors: Wagner William E. 
Published: May 2010

AbstractI studied variation in male calling behavior and its social correlates in Blanchard's cricket frog, Acris crepitans blanchardi. Calls were produced in distinct call groups, and they increased in duration and complexity from the beginning to end of a call group. Dominant frequency was the only character of 18 quantified consistently correlated with male snout‐vent length. Calls from the beginning of a call group varied independently of calls from the middle and end of a call group, and only calls from the beginning of a call group exhibited significant variation among males, thus relative consistency within males. Other characters varied greatly within individual males. Unlike most other anurans, dominant frequency also exhibited tremendous within‐male variation.The relative influence of caller density, local caller density, nearest neighbor distance, and nearest neighbor sound pressure level on variation in male calling behavior was examined. Nearest neighbor distance, mediated through the sound‐pressure level of neighbor calls, appeared to have the greatest influence on variation in male calling behavior. The most profound changes in calling behavior occurred during aggressive encounters; males altered their calling behavior in a manner suggesting that they respond to competitors with graded aggressive signals. Furthermore, the structure of the communication system suggests that calls are graded not only in response to the level of social competition, but graded over a call group as well.
Development of Nonsocial Behaviour in the Asiatic Elephant
Authors: Nair P. Vijayakumaran 
Published: May 2010

AbstractThe elephant calf, a defended follower is completely dependent on adults till the age of 3 months. It begins to explore and attempts to feed at 3 to 6 months, and then becomes partially independent with some feeding on its own. The characteristics of behavior in adults are examined and the development of this pattern in the calf is traced by analyis of duration, transition and clustering of the behavioural elements. Essential activities like suckling, locomotion and lying down for rest appear soon after birth whereas elements of feeding, grooming and play appear only at a later stage. The calf takes the initiative in suckling and its termination, drinking directly by mouth till the age of 6 months. The first element of feeding appears at about a week in attempts to pick up and hold objects in the trunk. Co‐ordination of limb, trunk and mouth movement is achieved by about 1 month. The calf is strong enough to pull out plants by 6 months when independent feeding begins. In about a year feeding, drinking and dusting patterns are well developed.
Sexual and Aggressive Behaviour in Species Hybrids of Poecilia mexicana and Poecilia velifera (Pisces, Poeciliidae)
Authors: Parzefall Jakob 
Published: May 2010

AbstractThe inheritance of sexual behaviour patterns was studied in species hybrids of Poecilia mexicana and Poecilia velifera. In addition, the aggressive behaviour and some morphological characters have been investigated and checked for a possible correlation between and within these three different traits studied. All the characters are inherited polygenically. The minimum genetic factors could be estimated only for some characters.
Temporal Aspects of Singing Interactions among Territorial Ovenbirds (Seiurus aurocapillus)
Authors: Popp James W. 
Published: May 2010

AbstractThe temporal aspects of singing interactions among birds have received relatively little attention. To determine if the song delivery of one individual is affected by that of its territorial neighbor, I recorded singing interactions between territorial ovenbirds (Seiurus aurocapillus). Ovenbirds appeared to adopt one of two roles during singing interactions, Type I or Type II singers. Type II singers placed more of their songs immediately after the song of their neighbor than expected. The singing pattern of Type I singers could not be distinguished from a random pattern with respect to their neighbor's songs. In each observed pair of interacting birds, one individual was a Type I singer and one was a Type II singer. Although there was some intra‐individual variation, most birds maintained the same role with each of their recorded territorial neighbors. Variation occurred between the two study sites in the extent that individuals overlapped the songs of their neighbors. Song overlap was common at one site, but occurred as, or less, often than expected at the other site.
Differential Response to Colors by the Lizard Uta palmeri (Reptilia: Iguanidae)
Authors: Hews Diana K. , Dickhaut Jeffrey C. 
Published: May 2010

AbstractMany lizards have brightly colored body parts thought to be signals, but color perception in lizards has not been well studied. We present data documenting differential response to colors in an iguanid lizard. Free‐living Uta palmeri differentially approached and bit at a red‐colored object when simultaneously presented objects of four different colors (red, blue, yellow, black). This response to red was statistically significant for all three age‐sex classes of lizards tested (adult males, adult females, juveniles). In addition, juveniles and adult females exhibited intermediate levels of responses (approaching and sniffing, and licking) to the yellow object but adult males did not. Seasonally important food items of this species are red (fish regurgitated by nesting seabirds) and yellow (yolk from broken seabird eggs), and response behavior (biting versus licking) was similar to that exhibited during feeding. Thus, as presented in our experimental paradigm, red and yellow elicited feeding responses.The spectral reflectance curves of the red and yellow stimuli were found to exhibit peaks at wavelengths of 630 nm (range 570–670), and at 600 nm (range 550–700), respectively. These values overlap with the spectral range of the gravid coloration of female U. palmeri (peak 615 nm, range 550–690) that is thought to be a signal to conspecifics. Furthermore, the reflectance curves are similar in shape and height (intensity). Thus, the similarities of the reflectance curves of the red paint and of the natural coloring suggest that palmeri can detect the female gravid coloration. Whether the response to red objects is due to discriminating differences in hue or in relative brightness remains to be examined.
Mother‐Infant Communication in the Lesser Spear‐nosed Bat Phyllostomus discolor (Chiroptera, Phyllostomidae) — Evidence for Acoustic Learning
Authors: Esser Karl‐Heinz , Schmidt Uwe 
Published: May 2010

AbstractWhen mother‐offspring couples of Phyllostomus discolor (lesser spear‐nosed bat) are reunited after separation, an intensive exchange of infants' isolation calls and mothers' directive calls can be observed. The directive calls of each mother show a distinctive frequency‐time structure, which appears to represent her individual vocal signature. During ontogenesis the isolation calls of the young change gradually, adapting increasingly to the mother's call type. A comparison of calls of separated pups at different ages with their mothers' directives demonstrated the individually distinct call characteristics of the mother also to be characteristic of the isolation calls of her young by about 50 days of age. This suggests that acoustic signals may be learned in Phyllostomus discolor.
Electric Organ Discharge Displays during Social Encounter in the Weakly Electric FishBrienomyrus nigerL. (Mormyridae)
Authors: Moller Peter , Serrier Jacques , Bowling Deborah 
Published: May 2010

AbstractWe investigated the electric organ discharge (EOD) activity of the mormyrid fishBrienomyrus nigerduring social encounters. The fish were contained in porous ceramic shelters and tested alone and in pairs in an experimental tank designed to restrict communication to the electrosensory modality. We moved one fish toward and away from a stationary conspecific, beginning at a distance known to be outside the range of communication (250 cm). Baseline EOD activity was recorded prior to interaction and categorized as ‘variable’, ‘regular’, and ‘scallop’. When moved closer together, the fish modulated this baseline activity in four ways: (1) At 100–130 cm apart, the stationary fish emitted a maximum of sudden EOD rate increases which defined the outer limit of its communication range. (The associated Electric Field Gradient was 1 μV/cm). (2) Long EOD cessations, which we called social silence, lasted from 5–130 s and occurred most frequently when the fish were 36 to 55 cm apart (EFG: 100 μV/cm). The duration of social silence was negatively correlated (r = − 0.862) with the responding fish's size, and was independent of the partner's sex and size. Fish whose EOD baseline pattern was ‘scallop’ were least likely to fall electrically silent, and those that were categorized as ‘regular’ or ‘variable’ were most likely to cease discharging. (3) Within electrolocation range, fish ‘regularized’ their EOD activity while the partner was ‘silent’ (EFG: 1 mV/cm). (4) Following long EOD cessations the fish resumed discharging with characteristic EOD rebound patterns. The possible ethological significance of these findings is discussed.
Pigeon Homing: Does Early Experience Determine what Cues are Used to Navigate?
Authors: Papi F. , Gagliardo A. , Fiaschi V. , Dall'Antonia P. 
Published: May 2010

AbstractTo test the hypothesis that early experience might determine the nature of the cues used to navigate, homing pigeons were made anosmic by nerve section before they could experience the natural odours in the region of the loft. They were allowed to make free flights and trained by flock releases with intact controls. Next they were tested and compared with intact controls as well as birds made temporarily anosmic just before the experiment. Initial orientation and homing performance of the experimental birds were very poor and showed that the pigeons were unable to acquire an alternative mechanism of navigation.
Asymmetrical Effects of Prior Winning and Losing on Dominance in Sticklebacks (Gasterosteus aculeatus)
Authors: Bakker Th. C. M. , Bruijn E. Feuth‐De , Sevenster P. 
Published: May 2010

AbstractReproductive male three‐spined sticklebacks, Gasterosteus aculeatus L., without fighting experience, were given either an experience of dominance or an experience of inferiority. They were then tested for their ability to dominate an inexperienced male in a dyadic combat either a) immediately following the experience treatment, b) 3 h later or c) 6 h later. The effect of prior losing proved to be stronger and more prolonged than that of prior winning. The influence of non‐experimental factors, and possible causes for this asymmetrical effect are discussed.
Discriminating between Hungry and Satiated Predators: The Response of Guppies (Poecilia reticulata) from High and Low Predation Sites1
Authors: Licht Thomas 
Published: May 2010

AbstractFixed anti‐predator activities are costly because they limit the ability of the prey to take advantage of short term temporal patchiness in predation pressure. The ability to discriminate between hungry and satiated predators and a flexible response to the differential threat can help to lower the costs of anti‐predator behavior. In this study Trinidadian guppies (Poecilia reticulata) were found to distinguish between hungry and satiated predators. In Trinidad, populations of guppies experience different levels of predation from piscivorous fish. Individuals taken from populations with chronically high predation pressure responded stronger to the hungry predator than those from low predation sites.