bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acoustic Communication in Woodhouse's Toad (Bufo Woodhousei)
Authors: Sullivan Brian K. , Leek Marjorie R. 
Published: April 2008

AbstractWe tested the hypothesis that acoustic stimuli must be similar to the species-typical advertisement call in both dominant frequency and pulse rate to attract female Woodhouse's toads (Bufo woodhousei) in discrimination trials. Using synthetic advertisement calls we determined that females always preferred a synthetic call with the species-specific pulse rate and frequency over synthetic calls in which only pulse rate or frequency was within the range for the species. However, appropriately pulsed, narrow-band filtered noise was a sufficient acoustic stimulus to attract 20% of the females in one-quarter of their discrimination trials. These results are discussed in light of species recognition in bufonids.
Costs and Benefits of Group Foraging in the Teal (Anas Crecca)
Authors: Pöysä Hannu 
Published: April 2008

AbstractThis study examines group foraging in the teal (Anas crecca) in the light of some hypothesized foraging and anti-predator effects of grouping. Results suggest that group foraging in the teal acts as an adaptation to exploit spatially and temporally variable feeding environments. First, in a particular feeding patch, teals responded numerically to the variation in prey abundance. Second, foraging groups attracted teals flying over them. Third, arrivals landed close to the foragers and copied feeding methods used by them. However, the use of marginal feeding sites within the patch increased with group size. This disadvantage and the disturbance and exploitation of prey at and near the water surface may decrease foraging efficiency in large groups. Contrary to the results of several other studies, time-budgeting advantage in terms of increased feeding time and decreased vigilance time seemed not to be an important anti-predator benefit of grouping in the teal.
Male Reproductive Tactics in the Libellulid Dragonfly Paltothemis Lineatipes: Temporal Partitioning of Territories
Authors: Alcock John 
Published: April 2008

AbstractMales of Paltothemis lineatipes defend stream-edge territories several meters in length. Receptive females fly to the stream to oviposit in very small patches of barely submerged fine gravel; each territory contains at least one but rarely more than two patches. Territorial males intercept incoming gravid females, copulate very briefly with them while hovering over a potential oviposition site, and then release their partners, which usually oviposit for less than 2 min before leaving the stream. Because mated females do not oviposit while in tandem with a male, neighboring territory owners sometimes succeed in stealing females before they have completed oviposition in their first mate's territory. Interrupted females sometimes are receptive, and may copulate with an intruder and oviposit in his territory. Gravid females arrive at the stream primarily in a 3 h mid-morning period during which time the density of territorial males is greatest. Fights for territories are most frequent early in the daily activity cycle, just prior to the time when receptive females are most likely to appear. There are many more males than sites with suitable oviposition substrate. Consequently competition for territories is intense, particularly at locations that attract relatively many females. From 2-4 males may claim favored territories in sequence on a given day, with the same males returning to partition ownership of the location temporally in the same order over several days. Temporal partitioning of certain territories in P. lineatipes appears to be a consequence of the males' ability to identify superior locations and superior times for territoriality, with the result that no one individual can monopolize a productive site for an entire daily flight period.
Recording Behaviour Using a Portable Microcomputer
Authors: Martin Paul , Unwin D.M. 
Published: April 2008

AbstractThis paper describes a microcomputer-based event recorder for recording behavioural observations. The system uses a widely available portable microcomputer (an Epson PX-8) and can be used for recording behaviour in a wide variety of situations. It combines the advantages of a keyboard event recorder with the ease of use and flexibility of paper-and-pencil methods (check sheets), and overcomes many of the problems inherent in specialised event recorders. With the event recorder program, the microcomputer can be used to record the frequencies, durations and latencies of many different categories of behaviour. With the check sheet emulator program, it can be used to obtain a time-sampled record of complex social behaviour, in the same way as with a check sheet. Listings of both programs, which are written in BASIC, are given. No computer programming expertise is required and no specialised hardware need be built in order to use this powerful, flexible and relatively inexpensive system.
Foraging Efficiencies and Techniques of Juvenile and Adult Northern Mockingbirds (Mimus Polyglottos)
Authors: Breitwisch Randall , Lee Ronald , Diaz Marilyn 
Published: April 2008

AbstractAdult and newly independent juvenile northern mockingbirds foraged on arthropods in the breeding season at similar rates within bouts, but adult efficiency (both as captures/attempt and captures/min) was higher than juvenile efficiency. Adults also captured a greater proportion of large arthropods than juveniles, and adults preferentially fed larger prey to dependent young. Juveniles engaged in more aerial attacks as the season progressed, although their success rate in these bouts did not increase. Both adults and juveniles captured a greater proportion of large arthropods in aerial attacks than in ground attacks. Juvenile success rate in ground attacks increased with season. These observations suggest that juvenile mockingbirds change their foraging behaviour in the first 1-2 months of independence, although the mechanism involved in this change is unknown.
Dominance Relationships in Jackdaws (Corvus Monedula)
Authors: Wechsler Beat 
Published: April 2008

AbstractDominance interactions (supplantings) of 26 jackdaws (Corvus monedula) living in a captive flock were recorded for a period of 2 years. The transitivity of the dominance hierarchy did not increase over time. Though there were 238 rank changes in course of the study, a portion of 6 % of all possible triads of the flock was always intransitive. Only 16.5% of the observed supplantings involved aggressive behaviour. There was no significant correlation between the body weight of a jackdaw and its dominance rank. Male-Male dyads had a disproportionally high frequency of dominance interactions and rank changes. Females were more likely to gain in rank in course of a rank change if their mate was already dominant to the opponent and to lose in rank if their mate was subordinate to the opponent. With the males there was no such tendency. Only 5.4% of the observed dominance interactions were temporary reversals with respect to the defined dominance relationship of a dyad. The probability of temporary reversals was increased if the mate of the supplanting jackdaw was present (less than 60 cm away) during the dominance interaction even though it did not interfere. When it was present, it joined the supplanting interaction in 10.0% of the cases. Breeding jackdaws had an increased percentage of reversed dominance interactions in front of their nest box. This site-related dominance was especially marked as soon as the female started to incubate.
Firing Activity of the Weakly-Electric Fish Marcusenius Macrolepidotus (Mormyridae, Teleostei): Logarithmic Repartition of Inter-Pulse Intervals, and Sequential Inequality Testing
Authors: Graff Christian 
Published: April 2008

AbstractThe electric activity of mormyrid fish consists of short electric pulses, all identical, but separated by variable time intervals (inter-pulse interval or IPI). Temporal structures are here extracted from the sequence of IPIs, to show non-randomness in mormyrid electric signal. The electric activity of isolated Marcusenius macrolepidotus is comparable to that of other mormyrids. The pulse waveform is biphasic and symmetrical, it lasts 0.3 to 0.5 ms and its amplitude is about 13 volts. The pulses follow each other with extremely variable IPIs (14-500 ms) with large instantaneous variations. Two new methods of analysis have been developed here. The first is based on the fact that when IPIs are grouped in populations, longer IPI populations have a wider range than shorter ones, a lognormal rather than a normal distribution. The IPIs are therefore classified according not to absolute- but to relative differences: binwidths are in percent, not in milliseconds. The second, non-parametric method (sequential inequality testing), was first used for neurone firing activity. It considers the sign (+ or -) of the difference between successive IPIs, and compares the sequence of these signs with a theoretical random model. When M. macrolepidotus is resting, the sequence of longer and shorter IPIs is not random, as shown by redundancies of patterns of + and - signs. These redundancies and the IPI populations are typical for each individual. When the fish increases its locomotor activity (either spontaneously for a few seconds, or provoked over more than 20 s) the IPIs are shorter. The patterns of + and - are different when the fish is swimming and when resting. Behavioral and electrophysiological data suggest that receiving conspecifics may recognize these rhythm features. The analysis methods developed here may be useful to other stochastic phenomena, such as neural firing activity.
The Significance of Persistent Vocalisation By the Spring Peeper, Pseudacris Crucifer (Anura: Hylidae)
Authors: Forester Don C. , Lykens David V. , Harrison W. Keith 
Published: April 2008

Abstract
1. Male spring peepers exhibit individual variation in calling persistence within as well as between nights. 2. Weather conditions influence nightly variation in calling persistence throughout the reproductive season, but there is a pronounced decrease in calling persistence late in the season which appears to be independent of climate. 3. In four speaker experiments simulating males calling 20, 40, 60, and 80% of the time, there is a positive correlation between time spent calling and mating success. 4. On nights when there is significant variation in calling persistence, females likely respond to those males which are most persistent (i.e. , produce the most conspicuous calls). 5. In four speaker experiments simulating males calling 80, 85, 90 and 95% of the time, mating success is random, suggesting that during periods of peak mating activity the importance of female choice is diminished. 6. Calling persistence is not correlated with body size, therefore males of any age or size class have an opportunity to experience mating success. 7. Anuran vocalization is known to be energetically expensive, and persistent callers (regardless of their size) are likely in good physical condition. 8. We suggest that by responding (either actively or passively) to the most conspicuous calls, females convey to their offspring an advantage above and beyond that accrued by random mating.
Memory for Reward in Probabilistic Choice: Markovian and Non-Markovian Properties
Authors: Davis Derick G.S. , Staddon J.E.R. 
Published: April 2008

Abstract
Pigeons were rewarded with food for pecking keys in various forms of two-armed bandit situation for an extended series of daily sessions in two experiments. The average daily preference (S=R/[R+L]) is very well fit by a markovian linear model in which predicted preference today is an average of predicted preference yesterday and reinforcement conditions today: s(N+1) = as(N) + (1-a)A(N+1), where A(N+1) is set equal to 1 when all rewards are for the Right response, and 0 when all are for the Left, and a is a longterm memory parameter. This linear model explains some apparent paradoxes in earlier reports of memory effects in two-armed bandit experiments. Nevertheless, closer examination of the details of preference changes within each experimental session showed several kinds of non-markovian effects. The most important was a regression at the beginning of each experimental session towards a preference characteristic of earlier sessions (spontaneous recovery). This effect, but not a smaller, less reliable non-markovian reminiscence effect, is consistent with a very simple rule, namely that the effect on preference of each individual reward for a Right or Left response is inversely related to how long ago the reward occurred. Thus, animals learn to prefer the rewarded side each day because these rewards are recent; but they regress to earlier preferences overnight because the most recent rewards become relatively less recent with lapse of time.
Evolution of Nonvisual Communication and Photoperiodic Perception in Speciation and Adaptation of Blind Subterranean Mole Rats
Authors: Nevo Eviatar 
Published: April 2008

AbstractThe evolution of vocal and vibrational communications and photoperiod perception in the blind subterranean mole rat of the Spalax ehrenbergi superspecies, are reviewed in the context of adaptation and active speciation in the subterranean ecotype. Progressive evolution of the acoustic system and regressive evolution of the atrophied eye coupled with progressive evolution in photoperiodic perception and biorhythmicity systems, are discussed. Prospects are suggested for future research at the molecular, anatomical and organismal levels, in the twin evolutionary processes of adaptation and speciation. Spalax appears to be a uniquely productive evolutionary model for the study of evolutionary structural reductions and hypertrophies as well as functional shifts in evolution. It provides particularly a rich observational and experimental material to critically evaluate the challenges recently levelled against the synthetic theory of evolution concerning gradualism in speciation, the "adaptationist programme", and the role of natural selection as a creative force in evolution.
Experimental Polygyny and Colony Closure in the Ant Messor Barbarus (L.) (Hym. Formicidae)
Authors: Provost Eric , Cerdan Philippe 
Published: April 2008

AbstractColonies of Messor barbarus are monogynous. At the laboratory, it is possible to form polygynous colonies. This experimental model was used to study the influence of the number of queens on the degree of colony closure: are polygynous colonies more frequently open than monogynous ones? Experiments in which alien workers were transferred between monogynous and polygynous colonies showed that the latter had a lower degree of closure. The queen might play a major role in the recognition processes between individuals belonging to either the same or different colonies.
Plumage Quality and Mate Choice in Mallards (Anas Platyrhynchos)
Authors: Weidmann Uli 
Published: April 2008

AbstractThe suspected relevance of plumage quality of drakes for the choice of mates by ducks has been confirmed in a series of experiments. Drakes were ranked according to the extent of naturally occurring blemishes (deviations from the plumage of an ideal drake) and introduced, two at a time, to a resident group of female "adjudicators", who would choose drakes by following one of them and/or by performing aggressive acts against one or both. We could predict the outcome in almost every case. In other experiments we could influence female choice by making attractive drakes ugly or unattractive ones more beautiful by means of staining and bleaching. The success in these experiments of isolating the effects of plumage quality from the many other factors which usually influence mate choice in females was a consequence of the drakes' apparent lack of interest in the females to whose pen they were introduced for a short time only. When several females chose the same good looking male, intense rivalry and aggressive behaviour occurred among the females. The possible effect of such rivalry on female mate choice was briefly examined; it appeared to be unimportant in our experiments.
Male Song as a Cue for Mate Choice in the European Starling
Authors: Eens Marcel , Pinxten Rianne , Verheyen Rudolf Frans 
Published: April 2008

Abstract
This study had two aims. First, we looked at individual differences in song characteristics between males of the European starling, and we related song behaviour to factors such as male age, pairing date, polygyny and male breeding success. Second, we experimentally tested whether song has an effect on female mating decisions. 1. During the breeding season, male starlings sing a very long and complex song consisting of a rapid succession of large number of different song types. We observed marked differences between males in average song bout length (a song bout was defined as a period of at least five seconds of song containing no pauses larger than 1.5 seconds) and in song repertoire size. Average song bout lengths ranged from 16 to 35 seconds. The individual repertoire size ranged from 23 to 67 song types. Repertoire size and average song bout length were positively correlated. 2. Both in the field and in captivity, yearling males sang shorter average song bout lengths and had smaller repertoire sizes than older males. 3. Males singing longer average song bouts and having larger repertoire sizes attracted females for pairing before their rivals with shorter average song bouts and smaller repertoire sizes.
Onset and Maintenance of Maternal Prey-Supply Activity in the Spider Coelotes Terrestris (Araneae, Agelenidae)
Authors: Bessekon Denis Assi , Horel Andre , Gundermann Jean-Luc 
Published: April 2008

Abstract
In the funnel-web spider Coelotes terrestris (Agelenidae) the young are provided with prey by their mother for several weeks following emergence from the egg sac. Such a maternal activity has previously been shown to be influenced by stimuli emitted by the young (i.e. during mother-offspring interactions), which ensures the tuning of the prey supply to the offspring. The present paper aims to shed light on the conditions of onset and maintenance of prey-supply tendency. The experimental procedure consisted in confronting females, either sub-adult or at various stages of their reproductive life cycle, with a group of spiderlings constant in number and age, and in recording the behavioural interactions following the capture of a prey item. Females which did not yet have post-emergence offspring did not supply prey to the spiderlings and exhibited aggressive reactions towards them. In contrast, females which had had post-emergence offspring, even though their dispersal could have taken place many weeks before, provided prey to the experimental spiderlings, and behaved towards them as their real mothers would have done. When exposure to the experimental situation was prolonged for one week, the tendency to supply the young clearly appeared in previously unresponsive adult females (inseminated or incubating), but no change was observed in sub-adults. The results show that, in Coelotes terrestris, the maternal tendency to supply prey requires a particular internal state, which seems to develop at the time of the offspring's emergence but which does not become extinct after their dispersal. The results also suggest that the development of this internal state can somehow be influenced by stimuli from the young.
Variation in Time and Energy Budgets of Breeding Wheatears
Authors: Moreno Juan , HILLSTRÖM Lars 
Published: April 2008

Abstract
We examined the sources of variation in time allocation of males and females of the wheatear (Oenanthe oenanthe) on the island of Öland, South Sweden, throughout the breeding season. We quantified rates of prey capture attempts and specified foraging methods used. From respirometric measurements of basal metabolic rate and temperature-dependent metabolism on captive wheatears, and after having made certain assumptions abour the costs of different activities, we estimated the energy budgets of both sexes during the different reproductive phases. Males and females differed in their time allocation and foraging rates during prelaying, laying, and incubation, but not while feeding grown nestlings. During prelaying and laying, females foraged at higher rates than males; they also perched less often, gleaned more on the ground, and flew less. Although incubation was the least costly phase for females because of their low activity, high foraging rates yet indicated that this phase may represent an energetic bottleneck as a result of restrictions on foraging time. After incubation, females switched from foraging mostly on the ground during early breeding phases to hunting from elevated perches during later breeding phases. The shift in foraging behavior corresponds to the drastic changes in time allocation. Relatively high daily energy expenditures (DEE) by brooding females coupled with low foraging rates may explain the observed posthatching body mass losses. In both sexes, high required energy acquisition rates when feeding large nestlings indicate that parent wheatears then may encounter another energetic bottleneck. Postfledging was the least costly phase because, compared with the period of feeding nestlings, there were reduced thermostatic costs and a marked drop in flight time. Males and females had similar DEEs during prelaying, laying and nestling feeding, but females had lower needs during incubation. The elective components of energy budgets during nestling feeding, as well as the estimated sum of the elective components throughout the season, were 12% higher for males than for females. The elective components of the energy budgets varied more than the obligatory components (basal + thermoregulation), especially in females, and were more important in determining the variation of DEE throughout the breeding season. A validation study with doubly labeled water indicated that the energy budget model used was accurate enough for comparisons between sexes or breeding phases, but not for measuring individual variation.
Pseudomale Behaviour and Spontaneous Masculinization in the All-Female Teleost Poecilia Formosa (Teleostei: Poeciliidae)
Authors: Schlupp Ingo , Parzefall Jakob , Epplen JÖRG T. , Nanda Indrajit , Schmid Michael , Schartl Manfred 
Published: April 2008

Abstract
Pseudosexual behaviour is a rare phenomenon associated with unisexuality in vertebrates. In the gynogenetic, all-female teleost Poecilia formosa, rare individuals occur that resemble males of closely related gonochoristic species both in behaviour and external morphology. These masculinized gynogens and normal gynogens are members of the same clone, as demonstrated by DNA-fingerprinting. The behaviour of these masculinized gynogens is described and compared to the behaviour of the gonochoristic species Poecilia mexicana, P. latipinna and their hybrid as well as androgen-treated individuals of P. formosa. No statistically significant differences were found between masculinized gynogens and hormone-treated individuals nor between the gonochoristic P. mexicana and P. latipinna males. Differences exist between gonochoristic and unisexual species. Possible causes and effects of masculinized gynogens are discussed.