bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sexual Competition, Coercive Mating and Mate Assessment in the One‐Sided Livebearer, Jenynsia multidentata: Are They Predictive of Sexual Dimorphism?
Authors: Bisazza Angelo , Manfredi Silvia , Pilastro Andrea 
Published: March 2003

AbstractWe investigated the mechanisms of sexual selection operating on body size in the one‐sided livebearer (Jenynsia multidentata), a small fish characterized by male dwarfism. Mating in the one‐sided livebearer is coercive: males approach females from behind and try to thrust their copulatory organ at the female genital pore. Females counter males' mating attempts by either swimming away or attacking them. We tested the hypothesis that the components of sexual selection favouring small size in males (sexual coercion) were more effective than those favouring a large size (male competition and mate choice). When alone, small males had a significantly higher success in their mating attempts than large males. The proportion of successful attempts was also positively correlated with female size. When two males competed for the same female, the large male had a significant mating advantage over the small one. With a 1 : 1 sex ratio, the large‐male mating advantage vanished because each male tended to follow a different female. Large males, however, preferentially defended large females, thus compelling small males to engage with smaller, less fecund females. Males did not discriminate between gravid and non‐gravid females, but preferred mating with larger females. This preference disappeared when males were much smaller than the female, probably in relation to the risk for the male of being eaten or injured by the female. In a choice chamber, male‐deprived females that had their sperm storage depleted remained close to males and showed a preference for large individuals, a behaviour not observed in non‐deprived females. Nonetheless, when placed with males in the same aquarium, all females showed avoidance and aggression. Struggling may represent a way by which the female assesses the skill and endurance of males.
How Similar is the Coordination of Parental Roles Among Different Pairs? An Examination of a Monogamous Fish
Authors: Itzkowitz M. , Santangelo N. , Richter M. 
Published: March 2003

AbstractAlthough most studies on biparental care assume that parents cooperate in raising offspring, few studies have documented how parents coordinate their activities. Using the biparental convict cichlid (Archocentrus nigrofasciatum) we compared the parental behavior of both single (‘widowed’) parents and individuals within pairs during the 5 d when the offspring were in the relatively uniform and stationary wriggler stage. In particular, we were interested in the consistency of day‐to‐day parental activities among single individuals and among individuals within pairs. Single parents showed differences in most parental activities that were consistent from one day to the next. This day‐to‐day consistency remained after an intruder was added and / or the mate was present. Thus, although the social context changed (i.e., presence or absence of mate, presence or absence of an intruder), an individual's consistency remained. The male and female within pairs were significantly correlated in the time spent on most parental activities across experimental pairs. Thus, while individuals within pairs were unique in their performance of a parental activity, paired males and females managed a high degree of correlation (i.e., coordination). In general, pairs were homogeneous in the degree to which males and females were correlated across different parental activities.
Reproductive Signals of Female Lizards: Pattern of Trait Expression and Male Response
Authors: Weiss S. L. 
Published: March 2003

AbstractRelative to the volume of studies concerning the function and evolution of male‐biased sexually dimorphic traits, instances of female‐biased sexual dimorphisms remain largely unstudied, especially in species with conventional sex roles. I investigated the signal function of a female‐specific ornamental trait using the striped plateau lizard (Sceloporus virgatus, Phrynosomatidae) as a model system. During the reproductive season, female S. virgatus develop orange color on their throats that is absent in conspecific males. I established the relationship between color expression and female reproductive state, and determined male response to female color. I show that dynamic changes occurring within the color patch can potentially identify each stage of the female reproductive cycle, largely because of a lag in patch growth relative to color intensification. Sexual receptivity is associated with intense patches rapidly growing in size; ovulation occurs near peak color expression; and the unreceptive period is associated with large patches fading in intensity. Because females express orange color during both the receptive and unreceptive periods, the pattern of color expression is consistent with the courtship‐stimulation and courtship‐rejection hypotheses of signal function. Males may preferentially associate with females that have more highly developed color patches during the courtship season, and/or ignore such females when they are unreceptive. An examination of male behavior towards unfamiliar females indicates that female color has a role in courtship stimulation but has little, if any, role in courtship rejection. During the pre‐mating season, males maintained significantly closer affiliation with, and tended to perform more social behavior towards females with more intense color. During the post‐mating season, female color had no apparent effect on male behavior. The evolution and current function of female ornaments may vary among taxonomically‐related species as a result of differences in ecology, social system, and life‐history.
Selective Learning in a Marsupial
Authors: Griffin Andrea S. , Evans Christopher S. , Blumstein Daniel T. 
Published: March 2003

AbstractBehavioural plasticity allows animals to adjust rapidly to local environmental conditions, but at the risk of erroneously changing behaviour in response to irrelevant events. Adaptive biases or predispositions constrain learning and reduce such potential costs. Preferential learning about complex biologically‐meaningful stimuli, such as predators, has been investigated in only a few systems and there have been no experimental tests for the presence of adaptive biases in a marsupial. We have previously shown that tammar wallabies (Macropus eugenii) became fearful of a model fox (Vulpes vulpes) after it was repeatedly paired with an aversive event. Tammars generalized their acquired response to a cat (Felis catus), but not to a non‐predator (juvenile goat, Capra hircus), suggesting that they might have a bias to associate predators with frightening events. The present study tested this idea directly. We used an experimental design identical to that of earlier predator‐training experiments, but substituted a model goat for the fox as the stimulus predicting a capture attempt. A control group had the same total experience of the goat and of a human with a net, but without any predictive relationship between these two events. We detected no change in behaviour towards the goat, or to any of an array of control stimuli, as a consequence of training. This finding contrasts strongly with the effects of the same pairing procedure using a fox model. Taken together, these studies provide the first evidence for an adaptive predisposition to acquire a fear of predators in marsupials. Learning processes in this group are thus evolutionarily convergent with those previously described in eutherian mammals.
Frequency of Encounter with Risk and the Tradeoff between Pursuit and Antipredator Behaviors in Crayfish: A Test of the Risk Allocation Hypothesis
Authors: Pecor K. W. , Hazlett B. A. 
Published: March 2003

AbstractPrey animals encountering multiple stimuli must often make behavioral tradeoffs. Many environmental cues may influence the tradeoff observed, but recent theoretical work suggests that temporal variation in risk should influence how prey animals behave during any given period of risk. As time spent under risk of predation increases, prey animals will increase their allocation of foraging during periods of risk. This model is known as the risk allocation hypothesis (RAH) (Lima & Bednekoff 1999). We tested the RAH using the crayfishOrconectes virilis. We selected two frequency regimes (exposure to risk every 6 or 12 h) and three cues suggestive of increasing risk (water, snapping turtle cue, and conspecific alarm cue). Test animals were exposed to one of the six frequency × risk combinations for 24 h, followed immediately by the simultaneous introduction of a food and a risk cue. Three behaviors (burrow use, non‐ambulatory motion, and locomotion) were then recorded for 5 min. Responses were significantly influenced by the interaction of risk and frequency. Further analysis indicated that responses were not consistently influenced by frequency alone. While our results do not support the predictions of the RAH for our frequency regimes, qualitative comparison with an earlier, similar study (Hazlett 1999) suggests that risk allocation is occurring in this system. We recommend that frequency of encounter with risk be considered in future studies. Ignoring temporal variation may lead to over‐ or underestimation of the subject's natural responses.
Responses to Playback of Local vs. Distant Contact Calls in the Orange‐Fronted Conure, Aratinga canicularis
Authors: Vehrencamp Sandra L. , Ritter A. F. , Keever M. , Bradbury J. W. 
Published: March 2003

AbstractWe conducted interactive playback experiments on foraging flocks of orange‐fronted conures, Aratinga canicularis, using loud contact calls that had been recorded at sites ranging from 0 to 30 km from the playback site. Responses were scored on the basis of the proximity of approach to the speaker, the number of different vocalizations produced by the responding flock, and the duration of respondent vocal interactions with the playbacks. Overall response strength decreased significantly as distance between playback and recording sites was increased up to 9 km, and remained at a steady low level for greater distances. As 9 km is the upper limit of conure home ranges measured in this study site, this nonlinear effect of response with distance suggests that response strength is partly determined by familiarity with calls of local birds. An additional and independent amount of the variation in response strength was explained by the structural similarity between respondent and stimulus calls. This correlation could be caused by a preference to interact with known stimulus birds whose calls have converged during prior associations. However, our data suggest that responding birds subtly changed their call structure during longer trials to more closely match the stimulus call. If subsequently verified as a common phenomenon, this finding could provide an important explanation for the remarkable imitative abilities of parrots.
Tree mortality caused by Gremmeniella abietina in a subalpine afforestation in the central Alps and its relationship with duration of snow cover
Authors: Senn J. 
Published: March 2003

SummaryTree survival and causes of mortality were studied in an experimental afforestation in the upper subalpine forest zone in the Swiss Alps. A total of 59.8% of Pinus cembra and 45.6% of Pinus mugo were killed by Gremmeniella abietina during the first 20 years after planting, compared to 1.5% of Larix deddua trees. The mortality rates caused by G. abietina were highly correlated with the duration of snow cover in spring. Tree losses were lowest at sites where the snow melted early and highest at sites where the snow ablation was delayed in spring. Tree mortality varied greatly between years. In the year after the coldest summer of the observation period mortality due to G. abietina infections was highest, suggesting high susceptibility of trees in poor condition. Phaddium infestans, which was the second most important factor for mortality in P. cembra, killed trees irrespective of their condition. Other biotic and abiotic causes of tree mortality had negligible influence compared with the impact of G abietina and P. infestans. Excluding anthropogenic impacts, the diverse spatial pattern of forested and treeless sites close to the subalpine timberline may predominantly result from the action of parasitic fungi, depending on the ablation pattern of the snow cover in spring.
Transfer of the P‐type of Heterobasidion annosum from old‐growth stumps of Picea abies to Picea abies and Larix×eurolepis
Authors: Vollbrecht G. , Stenlid J. 
Published: March 2003

SummaryThe infection of Picea abies and Larix x eurolepis by Heterobasidion annosum was studied in felled trees in Sweden. Thinnings were carried out in two stands of L. x eurolepis, 15 and 20 years old, and in a 25‐year‐old stand of P. abies, established on a site heavily infected by H. annosum. The 15‐ and 20‐year‐old L. x eurolepis stands exhibited the greatest incidence of butt rot with infections amounting to 38 and 57%, respectively, of removed trees. The incidence of butt rot in the P. abies stand was only 5%. Heterobasidion annosum was the main butt rot causing fungus. All isolates of H. annosum were of the P‐intersterility group. Transfer of H. annosum from old‐growth P. abies stumps to trees felled in the thinning of the next generation was demonstrated by somatic incompatibility tests. However, the majority of infections could not be connected with decay already established in the previous generation. In L. c eurolepis, rot columns were frequent, including also several genotypes in the same stem, and typically positioned in the inner sapwood. The few infections of P. abies were situated in the heartwood.
Endothia gyrosa associated with severe stem cankers on plantation grown Eucalyptus nitens in Tasmania, Australia
Authors: Wardlaw T. J. 
Published: March 2003

SummarySevere stem cankers in Eucalyptus nitens, from a 14‐year‐old mixed provenance plantation, were associated with infection by Endothia gyrosa, present in its teleomorph state. Surveys of incidence among canker severity classes were carried out in a thinned and pruned stand and an adjacent unthinned and unpruned stand within the affected plantation. No differences in incidence among the canker severity classes were found between the thinned/pruned and unthinned/unpruned stands or between different crown dominance classes within the unthinned/unpruned stand. However, the incidence among canker severity classes was strongly associated with bark roughness with 97% of rough‐barked trees developing either annual cankers or cankers causing cambial damage. Stem cankers were found on only 11% of trees with smooth bark. Bark roughness in E. nitens was shown to differ significantly between provenances. Deployment of provenances prone to rough bark in routine plantation establishment may pose a risk of damaging stem canker outbreaks.
Crown density changes of Norway spruce and the influence from increased age on permanent monitoring plots in Norway during 1988–1997
Authors: Solberg S. 
Published: March 2003

SummaryOn the ‘local county monitoring plots’ located throughout Norway a reduction of crown density has been noted during the period 1988–1997. The aim of this study was to determine whether this change could be attributed to normal effects due to the increased age of trees in the plots. The dataset comprised around 580 plots and 27 000 single trees of Norway spruce (Picea abies), with 10 years of crown density measurements available for each tree. A two‐step approach was used, first to search for an expectancy for normal reduction of crown density by age derived from the dataset, and then to compare this with the actual reduction. The interpretation was somewhat complicated as the various results were dependent upon each other. Highly significant correlations were found between crown density and age. The relationship indicated an annual reduction of crown density of around 0.12%. However, the relationship varied both between years and between regions, and it was not possible to definitely determine whether the relationship was best described by linear or nonlinear models. Of major importance here is that the relationship appeared to be influenced by the presence of stresses, whose effects tended to be more severe in old stands. On this basis it seems questionable whether an expectancy for normal ageing can be properly defined. In the present study, however, it could still be definitely determined that the mean crown density change of—0.41% annually was too negative to be attributed to normal ageing, as it was clearly below all the suggested expectancies from the various models. This suggests that the amount of stress in the period under study has been higher than normal, and this encourages the search for causal agents in further studies. Changes in silviculture may have had some influence. The results were valid for most of Norway, with the exception of western and northern regions. Crown density assessments are subjective, which may possibly give erroneous time trends. However, it is argued that this is less likely to be of major importance in the present data.
A serious new wilt disease of Eucalyptus caused by Ceratocystis fimbriata in Central Africa
Authors: Roux J. , Wingfield M. J. , Bouillet J‐P. , Wingfield B. D. , Alfenas A. C. 
Published: March 2003

SummaryIn a recent survey of Eucalyptus clones in the Republic of Congo, Central Africa, a serious wilt and die‐back disease of two different hybrid clones was observed. Affected trees ranged in age from approximately 6 months to 4 years. Isolations from symptomatic plant material consistently yielded a Ceratocystis species. On the basis of morphology and sequence data this fungus was identified as Ceratocystis fimbriata, a well‐known wilt and canker pathogen of many economically important plants. The Eucalyptus isolates were compared with other Ceratocystis spp. based on sequence data generated from the ITS and 5.8S region of the rRNA operon. The results confirmed the identity of the Ceratocystis isolates from Eucalyptus as C. fimbriata and showed that they group with other C. fimbriata isolates from Brazil, South Africa and Europe. Inoculations on young Eucalyptus plants were conducted in the greenhouse and all three of the Congolese isolates tested, produced typical lesions in the bark and xylem. This study represents the first report of C. fimbriata as a pathogen of Eucalyptus in Africa. This is a serious new disease that will require considerable study in order to ensure that losses, caused by C. fimbriata, do not continue.
Serpula himantioides, Heterobasidion annosumandCalocera viscosaas butt rot fungi in a Danish Douglas‐fir stand
Authors: Koch J. , Thomsen I. M. 
Published: March 2003

SummaryA scattered wind fall of 50 trees in a 46‐year‐old stand of Douglas‐fir (Pseudotsuga menziesii) revealedSerpula himantioides, Heterobasidion annosumandCalocera viscosaas decay causing fungi. Sixty‐four percent of the stumps had visible rot on the stump surface. Mainly, a central brown rot was seen, caused by eitherS. himantioidesorC. viscosacombined with eccentrically placed spots of incipientH. annosumrot. Subsequently, the appearance of fruitbodies disclosed that in total 76% of the wind thrown trees were associated with one or more of the three decay fungi.S. himantioideswas present in a surprisingly large number of trees (54%), and the rot column extended up to 2 m into the stem. This investigation represents the first known incidence ofS. himantioidesandC. viscosacausing root and butt rot in living conifers in Denmark.
Children of parents with mental illness. I: An overview from a nursing perspective
Authors: Devlin Janet M. , O’Brien Louise M. 
Published: March 2003

ABSTRACTThis paper explores the psychosocial consequences of parental mental illness for child mental health and the implications for mental health nursing. The literature on risk and vulnerability to psychosocial disorder, resilience, child protection, disorder prevention and epidemiological data are reviewed. Based upon a health promotion approach, a model for mental health nursing advocacy for families of adult consumers is proposed as an effective means of preventing disorder in subsequent generations.
Preliminary results from an Australian psychosocial rehabilitation program for people with serious mental illness
Authors: Bruseker Robert , O’Halloran Paul 
Published: March 2003

ABSTRACTPsychosocial rehabilitation, for those with a serious mental illness, is of significant importance due to both its frequency and cost to government. This paper describes the implementation and preliminary assessments of a new psychosocial rehabilitation program in New South Wales. Of particular urgency was the requirement to establish baseline measures for ongoing service evaluation at the unit. An extensive array of assessment tools (Brief Psychiatric Rating Scale, BPRS; Scale for the Assessment of Negative Symptoms, SANS; Quality Of Life Scale, QOLS) was applied to determine the functioning of clients prior to the program. Following the initial assessments, subsequent measures were undertaken on completion of the program and then at 1 year follow‐up. It was hypothesized that the clients would demonstrate significant improvements on these measures with a reduction in their psychopathology as assessed by the BPRS, improvement in their quality‐of‐life as measured by the QOLS and improvement in their negative symptoms as measured by the SANS. The final outcome demonstrated improvement in the assessment scores by 34%. A positive correlation to the above results showed a 54% reduction in the re‐admission rate of clients and length of stay in hospital. The paper describes further developments regarding this psychosocial rehabilitation unit and suggests other psychosocial rehabilitation initiatives.
Staff confidence in dealing with aggressive patients: A benchmarking exercise
Authors: McGowan Sunita , Wynaden Dianne , Harding Neil , Yassine Assaad , Parker John 
Published: March 2003

ABSTRACTInteracting with potentially aggressive patients is a common occurrence for nurses working in psychiatric intensive care units. Although the literature highlights the need to educate staff in the prevention and management of aggression, often little, or no, training is provided by employers. This article describes a benchmarking exercise conducted in psychiatric intensive care units at two Western Australian hospitals to assess staff confidence in coping with patient aggression. Results demonstrated that staff in the hospital where regular training was undertaken were significantly more confident in dealing with aggression. Following the completion of a safe physical restraint module at the other hospital staff reported a significant increase in their level of confidence that either matched or bettered the results of their benchmark colleagues.