bluuebunny/crossref_metadata_2025 huggingface dataset:
Territorial Pheromones of Female Red‐backed Salamanders
Authors: Horne Eva A. , Jaeger Robert G.
Published: May 2010

Pheromones provide an important source of communication during social interactions of caudate amphibians. To further examine their use in territorial defense, we performed a laboratory experiment to test the hypothesis that non‐courting female red‐backed salamanders (Plethodon cinereus) deposit pheromones in or on fecal pellets, as males are known to do during territorial advertisement. Four conditions were tested: (1) a burrow marked with a female's own pellet vs. a burrow marked by a conspecific female's pellet, (2) own vs. unmarked burrows, (3) conspecific vs. unmarked burrows, and (4) paired unmarked burrows as a control. Females nose‐tapped (for olfactory cues) their own and conspecific pellets about equally. However, they spent significantly more time in both threat and submissive behavior toward the conspecific pellets and spent significantly more time in their own marked burrows. We infer that female P. cinereus do deposit pheromones in or on fecal pellets and that these pellets may be used to advertise territories. The behavioral responses of females toward pellets of other females were more aggressive than those of males (in a previous study) toward pellets of other males.
An Extreme Case of Interspecific Territoriality: Male Anthidium manicatum (Hymenoptera, Megachilidae) Wound and Kill Intruders
Authors: Wirtz Peter , Szabados Michael , Pethig Horst , Plant John
Published: May 2010

Anthidium manicatum males defend patches of flowering plants as mating territories and copulate with females that enter the territory to obtain nectar or pollen. Territorial males defend their territories not only against conspecific males but also against many other insect species that attempt to utilize the flowers inside the territory. In our study area, a territorial male defended its territory against conspecific males on average only twice per h but it attacked other species of insects on average 70 times per h. Territorial males distinguished between different species of intruders and attacked them unequally. During the hour following experimental removal of the territory holder the number of intruders of some insect species tripled but the number of intruders of those species that were rarely attacked remained approximately the same.

A. manicatum males, but not females, bear long spines on the last two segments of the abdomen. Territorial males rammed intruding insects at high speed and shortly before the moment of impact they curved the abdomen forward to hit with the spines. Intruders could be seriously damaged or killed by these attacks. Abdominal spines of A. manicatum males may have evolved as weapons to increase the effectiveness of interspecific territoriality.
Colony Founding by Queens of the Obligatory Slave‐making Ant, Polyergus breviceps: The Role of the Dufour's Gland1
Authors: Topoff Howard , Cover Stefan , Greenberg Les , Goodloe Linda , Sherman Peter
Published: May 2010

We conducted laboratory studies of the process by which newly‐mated queens of the slave‐making ant Polyergus breviceps invade colonies of their host species Formica gnava, kill the resident Formica queen, and appropriate the brood. The aggressive behavior of resident Formica workers towards the invading Polyergus queen subsides shortly after the Formica queen is killed. To elucidate the chemical basis for the reduction in aggression, we prepared extracts of Dufour's, pygidial, and poison glands from Polyergus queens. Workers of the harvester ant Pogonomyrmex occidentalis were daubed with these extracts, and introduced into dishes containing Formica workers. Only the Dufour's secretion protected the intruding ants from incessant aggression by Formica. Preliminary studies also show that the enlarged, bilobed Dufour's gland of the Polyergus queen decreases in size shortly after mating, when developing oocytes occupy a significant portion of the queen's gaster.
Breeding Season Aggression of Female and Male Eastern Bluebirds (Sialia sialis) to Models of Potential Conspecific and Interspecific Egg Dumpers
Authors: Gowaty Patricia Adair , Wagner Steven J.
Published: May 2010

Naturally occurring aggression between female eastern bluebirds (Sialia sialis) is dramatic, resulting in severe injuries and even death. Furthermore, aggression among bluebirds is usually sex specific: males attack males, females attack females. We hypothesized that the primary function of female‐female aggression is to guard against the threat of intraspecific egg dumping and that, in this context, same sex aggression is related to the possibility of advantages for males of parasitism (egg dumping) of their nests. Our hypotheses to explain variation in naturally occurring aggression predict temporal variation in aggressive tendency within nest cycles and between the sexes depending on asymmetries in threats to the residents. We report the results of experimental trials in the field designed to determine temporal variation in the aggressive tendencies of resident females to models of intruder females of two species, eastern bluebirds and brown‐headed cowbirds (Molothrus ater). Both species dump eggs in the nests of bluebirds. Female aggression to eastern bluebird models is greatest during early stages of nest cycles; the patterns are most consistent with protection against egg dumping and protection of nest sites from usurpation. Male residents seldom attack female eastern bluebird models, but often attack models of female brown‐headed cowbirds, a result inconsistent with the hypothesis that patterns of differential parental care control aggression of female and male residents.
Geomagnetism and the Homeward Orientation of the Box Turtle, Terrapene Carolina
Authors: Mathis Alicia , Moore Frank R.
Published: May 2010

Homing in the box turtle, Terrapene Carolina, has been well documented, but the mechanisms involved are largely unknown. We used laboratory and field experiments to determine if the geomagnetic field may be used as an orientational cue. Turtles were trained in the laboratory to move along an east/west axis and were tested for directionality in a circular arena. Control turtles with dummy weights attached to the carapace oriented significantly to the training direction. Experimental turtles with magnets attached to the carapace were randomly oriented. In field tests, turtles were displaced from their home ranges to 4 release sites located symmetrically about the home site. Controls were displaced under normal magnetic field strength (Helmholtz coils off) and experimentals were displaced under increased field strength (15% increase over local geomagnetic field strength). The initial orientation of the control turtles clustered significantly in the homeward direction while the initial orientation of experimental turtles was not clustered in the homeward direction. Both control and experimental turtles showed compass orientation clustered in an eastward direction regardless of the directional relationship between the release site and home. This compass orientation appears to mask, to some degree, the homeward orientation of the turtles.
The Cooperative Breeding System of the Red‐cockaded Woodpecker
Authors: Walters Jeffrey R. , Doerr Phillip D. , Carter J. H.
Published: May 2010

The breeding system of the red‐cockaded woodpecker is described based on data collected over six years from a population of 500 marked individuals in the Sandhills of North Carolina. Male‐female pairs were the most common social unit (59%), but 30% of social units contained one or more adult helpers, and 11% consisted of solitary males. Helpers were almost exclusively male: 27% of males remained in their natal group as helpers for at least one year, whereas only four (1%) females did.

Most breeding females remained as breeders in the same group from one year to the next (56%), but a surprising number (12%) moved to another group. Many movements were related to incest avoidance or mate death, but 39% involved deserting a mate, usually following successful reproduction. We suggest that females sometimes are forced from groups by immigrants or other group members. The median distance of movements by adult females was only 1.3 km. In contrast to females, no breeding males switched groups. Survival of both breeding (76%) and helper (80%) males was higher than that of breeding females (69%).

Males exhibited two distinct life‐history strategies. Some remained as helpers on their natal territory for one or more years, and became breeders by inheriting breeding status in the natal group (17% per year) or by replacing a deceased breeder in a nearby group (13% per year, median distance moved 1.0 km). Other males dispersed from their natal group permanently during their first year. Some of these males were floaters at age one year, others were solitary, and a few became helpers in a non‐natal group, but many were breeders. In contrast to males that first functioned as helpers, those that dispersed after fledging moved long distances (median dispersal distance 4.5 km), longer even than dispersing female fledglings moved (median distance 3.2 km).

The habitat saturation model of the evolution of cooperative breeding is based on selection between the two life‐history strategies exhibited by male red‐cockaded woodpeckers. The model therefore may be tested directly with this species. Another indication that this model is appropriate for this species is the existence of a resource (cavity trees) that might provide an ecological basis for habitat saturation.
Spatial and Temporal Distribution of Song in the Yellowhammer Emberiza citrinella
Authors: Møller Anders Pape
Published: May 2010

The temporal and spatial distribution of song was studied in a population of yellowhammers Emberiza citrinella. Song was most frequent during the breeding season, and within the breeding season during the fertile period of both first, second, and replacement clutches. Song activity peaked at sunrise and sunset. During the fertile period most singing took place in the central parts of the territory. Song post heights peaked during the fertile period, and more song posts lacked foliage at that time. Intrusions by male conspecifics peaked in the fertile period and in territories where males sang relatively little. Song activity and mate guarding were strongly positively correlated. Song volume was loud and song was thus apparently used in long‐distance communication. These observations are in accordance with a male deterrence hypothesis, suggesting that males sing to deter neighbouring males from trespassing during the fertile period of their mate. A female attraction hypothesis, suggesting that males sing to attract neighbouring females and thereby obtain extra‐pair copulations, and a female reproduction hypothesis, suggesting that males sing to start the female reproductive cycle, were partly supported by observations.
The Mode of Orientation during Flight and Approach to Landing in two Phyllostomid Bats
Authors: Joermann Gerhard , Schmidt Uwe , Schmidt Christel
Published: May 2010

The use of vision during flight and approach to a landing site in two phyllostomid bat species, Phyllostomus discolor and Desmodus rotundus was investigated. Three individuals of each species were trained to traverse a 3‐m flight tunnel and to land at a small illuminated grid that was randomly changed between two positions on a front wall. Analysis of the flight path by observation and different technical methods revealed that the bats oriented themselves toward the grid quite early. When the illumination was switched off the flight path diverged much later. With a dark landing grid on one side and an optical projection of it on the other the bats aimed towards this dummy, interrupted the approach 20–40 cm in front of the illusion and then tried to reach the other side or turned back. Whether microchiroptera may rely in the medium range more on vision than usually is thought is discussed.
Chicks in a Novel Environment: Effects of Conspecific Calls
Authors: Vallortigara Giorgio
Published: May 2010

Ambulation latencies of 2‐ and 7‐day old chicks individually placed in a novel environment were measured (1) in presence of distress calls; (2) in presence of trills of pleasure; (3) without acoustic stimuli. Results showed that in 2‐day old chicks there were no differences in ambulation latencies between chicks tested with and those tested without acoustic stimuli. In 7‐day old chicks ambulation latencies were higher in chicks tested with distress calls or trills of pleasure than in chicks tested without conspecific calls. Results are discussed on the basis of the Gallup & Suarez's (1980) hypothesis that open‐field behaviour in chicks represents a compromise between opposing tendencies to reinstate social contact with imprinted companions and to reduce detection in the face of possible predation.
Aggressive, Sexual, and Foraging Behaviour in Poecilia velifera (Pisces: Poeciliidae) during Captivity1
Authors: Bildsøe Mogens
Published: May 2010

Foraging, agonistic, and sexual behaviour in heterosexual groups of Poecilia velifera were examined during conditions of captivity. Social organization was found to resemble what was previously found in other poeciliids, hierarchies being established within each sex. Males showed considerably more aggressive activities than females, and alpha males tended to dominate all individuals.

Aggressiveness is the only measure where dominating individuals exceed submissives. Levels of aggressiveness higher than a specific value may have negative influences in gaining access to resources: Those individuals with highest or lowest scores for aggressive behaviour were low scoring with respect to sexual and foraging behaviour.

Attempts were made to separate factors determining aggressiveness in competition for food and mates by observing in periods with and without food being presented. Only beta individuals changed levels significantly: females decreased both chasing and biting during non‐feeding periods, whereas males only decreased biting.

Sexual behaviour in terms of butting tended to decrease in alpha and increase in omega males during non‐feeding periods, whereas beta males in the same periods showed significantly decreased levels of both butting and gonopodial thrusting.
Behavioral Energetics of Lactation in a Herbivorous Carnivore, the Red Panda (Ailurus fulgens)
Authors: Gittleman John L.
Published: May 2010

In most mammals, the energetic costs of lactation significantly increase a female's daily energy requirements. Previous research indicates that such energetic costs may be met through changes in increased food consumption ranging from around 35 % to 150 %. In this paper, changes in food intake during lactation are measured in the red panda (Ailurus fulgens), a species of the order Carnivora which possesses a digestive system suited for a carnivorous diet but yet exclusively feeds on bamboo.

Four feeding characteristics were studied: duration of feeding bouts, number of bamboo leaves consumed per mouthful, number of bamboo leaves consumed per minute, and interval between mouthfuls of bamboo. In three lactating females, three of four feeding behaviors significantly increased up to 200 % above the rate observed during non‐lactation. Males showed no change in feeding behavior during the same reproductive months with identical available foods. Red pandas appear to suffer a more severe energetic cost during lactation (at least with respect to food consumption) than other mammals previously studied. This may relate to their inefficient digestive capacity to process a herbivorous diet of bamboo. The data presented here suggest that general discussions of the relative costs of reproduction and in turn parental investment should include a female's relative digestive efficiency during stressful reproductive periods.
False Alarm Calls as a Means of Resource Usurpation in the Great Tit Parus major
Authors: Møller Anders Pape
Published: May 2010

Great tits Parus major regularly gave alarm calls in winter without the presence of actual or potential predators. Such false alarm calls were given to deceive both conspecifics and heterospecifics. False calls were given when flock‐feeding sparrows Passer spp. monopolized a concentrated food source; if the food resource was dispersed false alarm calls were not used, independently of the presence of sparrows. Dominant great tits used alarm calls deceptively if a dominant conspecific was present on a concentrated food source but not if a subdominant individual was present; subdominant great tits were displaced by means of threat displays. Subdominant individuals gave false alarm calls both if dominant or subdominant conspecifics were present. False alarm calls were especially used when food was scarce or when great tits were feeding at a high rate, i.e. during snow storms and in the morning and the afternoon.
Plasma‐Testosterone Development in Colony and Individually Housed Male Guinea Pigs
Authors: Sachser Norbert , Proöve Ekkehard
Published: May 2010

The behavioural development of male guinea pigs was studied in two colonies of 12 males and 12 females each, from their 30th to their 360th and 540th days of age respectively, living in enclosures of about 8 m2. Changes in plasma‐testosterone (T) concentrations were determined in individually (N = 8) (IM) and colony housed males (N = 10) (CM) from their 30th to their 360th days of age. In IM T‐titers did not change significantly over time. In CM T‐titers increased significantly from 30 to 90 and 120 days of age respectively, declined to lower levels until day 210, rose significantly at 240 days of age and remained on relatively high levels until day 360. CM showed significantly higher T‐titers than IM on days 90, 120 and 240. In CM the first T‐peak might reflect hormonal puberty. At this time CM, however, displayed low amounts of courtship and agonistic behaviour. The 2nd T‐peak (240 days of age) occurred at an age when CM could achieve high ranking social positions for the first time which allowed reproductive success. It might be caused by the intense increase in sexual and agonistic behaviour during this period. In individual CM no general relationship between behavioural and endocrine development was found. At all ages T‐titers poorly reflected behavioural differences between CM. Overall, androgen development did not follow a fixed temporal pattern during ontogeny but was strongly influenced by the social environment.
Kelp gulls, Larus dominicanus, are Parasites on Flesh of the Right Whale, Eubalaena australis
Authors: Thomas Peter O.
Published: May 2010

Few birds parasitize living tissue of other birds or mammals. At Golfo San Jose, Argentina, kelp gulls, Larus domincanus, fed on live southern right whale, Eubalaena australis, mothers, landing on their backs and pecking at peeling skin or gouging into the energy‐rich hypodermal blubber layer. Most attacks occurred while mothers were resting at the surface in the central nursery area. The typical immediate reaction of mothers to gull attacks was to lower the mid‐back and rapidly raise the head and tail stock. Less frequently mothers submerged quickly. After their initial response mothers traveled rapidly, usually underwater, or adopted resting postures that submerged the vulnerable midback area. Gulls attacked singly or in small groups and alternated between following a single pair of whales and attacking several pairs sequentially. The intensity of maternal responses to these attacks affects the energy budget of mothers and calves during a time when energy conservation is important. Subtle postural shifts to submerge the back require less energy than rapid, frantic fleeing. Since gulls feed on whales without causing fatal injury this relationship is termed parasitic.
Seasonal Differences in Social Behavior among Adult and Juvenile Meadow Voles, Microtus pennsylvanicus
Authors: Ferkin Michael H.
Published: May 2010

Seasonal differences in behavioral interactions between wild‐caught adult and juvenile meadow voles, Microtus pennsylvanicus, were measured in paired encounters in a neutral arena. Seasonal differences existed in the adult‐juvenile paired encounters. Early in the breeding season (May—Aug.) paired encounters between adult males and juvenile males were more agonistic than other adultjuvenile pairings. Late in the breeding season (Sep.—Dec.) adult female‐juvenile male encounters were more agonistic than other adult‐juvenile pairings. Odor preferences of juveniles were determined in a Y‐maze olfactometer. Juveniles did not demonstrate seasonal differences in odor preference. Males preferred the odor of adult females to the odor of adult males or their own odor. Females preferred the scent of an adult male to the odor of an adult female, but did not show a preference between their own odor and the odor of an adult male or an adult female. The results are consistent with hypotheses that state in a promiscuous species, females should be philopatric, and males should disperse as a consequence of adult competition. The data suggest that agonistic behavior by adults may regulate juvenile dispersal and recruitment, and define the composition of overwintering groups.
Parental Investment and Division of Labor in the Midas Cichlid (Cichlasoma citrinellum)
Authors: Rogers William
Published: May 2010

The 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

The 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

How 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

The 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

Humpback 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

The 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

Male 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

We 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

I 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

The 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

The 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

The 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

Many 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

When 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

We 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

To 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

Reproductive 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

Fixed 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.
Hilltopping in the Pipevine Swallowtail Butterfly (Battus philenor)
Authors: Rutowski Ronald L. , Alcock John , Carey Michael
Published: May 2010

In central Arizona, receptive females of the pipevine swallowtail, Battus philenor, are widely scattered in time and space, and in this region the butterfly's mating system is one in which males patrol mountain peaks. Hilltopping males engage intruding males in ascending flights that appear to be ritualized aerial combat with individuals defending patrolling sites for relatively short periods on any given day. The day‐to‐day appearance of marked males is irregular, unlike the site fidelity shown by males of many other hilltopping insects. The distinctive pattern of male territoriality in B. philenor may be partly a response to very low male and female density in the observed population. Males at the hilltop chase, court, and attempt to copulate with virgin females released near them. Males assess the receptivity of females rapidly, and receptive females permit a lengthy copulation to occur after a courtship that lasts less than 30 s. During an initial copulation males pass a spermatophore that weighs about 6% of their body mass, with partners on following days receiving a smaller but still substantial donation.
A Test of Inbreeding Avoidance in the Zebra Finch
Authors: Schubert Claudia A. , Ratcliffe Laurene M. , Boag Peter T.
Published: May 2010

Optimal‐outbreeding theory suggests that the genetic relatedness of individuals may be an important factor in mate choice. Several studies have demonstrated that matings between individuals of intermediate genetic relatedness tend to produce more offspring than those between more closely or distantly related mates. Inbreeding avoidance has been studied in captive zebra finches, Poephila guttata. Slater & Clements (1981) found a preference for closely related individuals, while Evans‐Layng (1987), in a different design, found a preference for less related mates. Our study examines patterns of mate choice in small flocks of zebra finches of known genetic relatedness. 13 flocks of 9 birds (3 females and 6 males) were released into separate aviaries and left until pairs had formed. 6 of these flocks consisted of siblings and nonrelatives and 7 consisted of cousins and nonrelatives. The degree of genetic relatedness of the individuals used did not affect mate choice, while factors such as male age and experience were correlated with mating success. There was a marginally significant trend for sibling pairs to take longer to lay eggs, although no overall difference in clutch size among sibling pairs, cousin pairs and genetically unrelated pairs was detected. We conclude, then, that there is no evidence of inbreeding avoidance in captive zebra finches.