Experimental evidence of reciprocal altruism in the pied flycatcher

Although human behaviour abounds with reciprocal altruism, few examples exist documenting reciprocal altruism in animals. Recent non-experimental evidence suggests that reciprocal altruism may be more common in nature than previously documented. Here we present experimental evidence of mobbing behaviour, the joint assault on a predator in an attempt to drive it away, as reciprocal altruism in the breeding pied flycatcher (Ficedula hypoleuca). Given a choice, pied flycatchers assisted in mobbing initiated by co-operating neighbours and did not join in mobbing when initiated by conspecific neighbours which had defected from necessary assistance 1 h before. The results suggest the birds followed a ‘tit-for-tat’-like strategy and that mobbing behaviour of breeding birds may be explained in terms of reciprocal altruism.     

Participatory ergonomics and an evaluation of a low-cost improvement effect on cleaners' working posture.

Cleaning is a highly physically demanding job with a high frequency of awkward postures and working environments as contributing risk factors. Participatory ergonomics is a method in which end-users take an active role in identifying risk factors and solutions. The aim of this study was to apply the participatory ergonomics method to identify cleaning problems and to evaluate the effect of a low-cost improvement on cleaners' working postures in an office environment. The results show that the cleaning problem was identified, and the low-cost ergonomics solution suggested by the cleaners was implemented. Thus an improved working environment reduced the number of awkward cleaning postures and the Ovako Working Posture Analysis System (OWAS) action category for floor mopping decreased. It can be concluded that working in an improved environment can lead to better working postures which, in turn, leads to the cleaners' better health and better cleaning results.     

波罗的海生态系统的概念化模型:用于环境决策的跨学科研究工具

为解决波罗的海地区与水体富营养化有关的环境和社会问题,加强该区域的跨学科研究的呼声越来越高.开展自然科学、社会经济学,以及管理学领域专家之间的合作是有必要的.解决不同领域专家之间相互交流的一个途径是建立一个内容广泛的概念模型,对富营养化进行综合性描述,并以可视化的方法将富营养化的起因、影响及多重关系连结起来.在现有的概念模型中,富营养化过程被分为1)起因;2)主要影响;3)次要影响;以及4)社会经济响应4个部分.对每一部分分别进行描述和讨论,并与其它层次和内容连结起来.通过模型可以看出从自然科学到人类社会间的可能途径,从而引出管理选项.作为例子,本文列举了对波罗的海富营养化的原因和影响进行观测与研究的关键文献,并对其提出的结论进行了讨论.     

Population structure and accumulation of lipids in the ctenophore Mertensia ovum

We studied the abundance, length-frequency distribution and body composition (lipid accumulation) of the ctenophore Mertensia ovum in Kongsfjorden, Svalbard (79°N) between May 2001 and April 2002. The highest abundances were found during summer in the outer and middle areas of the fjord, possibly caused by the concentration of advected zooplankton. Polymodal length-frequencies indicated a life span of 2 years, with 0, 1 and 2-groups being present in summer. Total lipid for a standardized animal decreased from May to August, and increased to the highest level in September. Relative lipid content was always highest in the 0-group, probably reflecting reduction of lipid levels due to increased energy costs during reproduction for the older age groups. Lipids probably are used to fuel prolonged reproduction from May to August until spawning ends by September. The overwintering age groups (0 and 1) subsequently build up lipid reserves for the next years’ spawning.     

The effects of parasites on male ornaments and female choice in the lek-breeding black grouse (Tetrao tetrix)

Summary We describe the results of two studies of parasitic infection in the black grouse (Tetrao tetrix). The first deals with our own observations of lekking black grouse in which the parasite levels of two blood parasites, the protozoan Leucocytozoon lovati and microfilaria, probably produced by a nematode worm Splendidofilaria tuvensis, were scored. We also obtained measures of age, survival, number of copulations, body mass and length of the ornamental tail feathers (the lyre) of the lekking males. The second study analysed the data from Lund (1954) which involved eight gut parasites obtained from birds which were killed. In the first study we found higher levels of infection of Leucocytozoon in adults relative to young birds. Parasites had no effect on male survival and there was no correlation in infection between the two types of parasites. Birds infected with microfilaria had shorter tail ornaments. There was no relationship between parasitic infection and mating success. However, the data indicated that such a trend indeed may exist for Leucocytozoon and the most successful males on the leks were less often infected by Leucocytozoon than other males. Results of the second study showed a negative relationship between parasite load (a combined measure of all parasites) and both ornamental tail feather length and body mass. These observations are compatible with, but not conclusive evidence for, the hypothesis of Hamilton and Zuk (1982) on the evolution of secondary sexual characters, where females choose to mate with genetically resistant males which show their resistance by expressing larger and more showy secondary sexual characters. Alternative explanations for the observed patterns are: females avoid infected males for some immediate benefit; and/or parasite loads are indicators of general stress rather than genetical resistance. Under the latter hypothesis females could mate with more vigorous males for reasons unrelated to parasite resistance.     

Stress on and off the job as related to sex and occupational status in white-collar workers

Sixty healthy non-smoking white collar employees, aged 30–50, from a large corporation in Sweden participated in the study. There were four groups: 15 male and 15 female middle managers, 15 male and 15 female clerical workers. Each participant was examined individually with regard to cardiovascular and neuroendocrine functions and self-reports for 12 consecutive hours under each of two conditions: (1) a normal day at work (9 a.m.–5 p.m.) and after work (6–9 p.m.), and (2) for the same time period during work-free conditions at home. In addition, everyone was given a videotaped type A-interview and a general health check-up including blood-lipid determination. Attitudes towards work, total workload (including responsibilities outside the paid work) and sex role identity were examined by questionnaires. As expected, all groups showed a moderate increase in cardiovascular and neuroendocrine activity during the day at work. After work, however, interesting group differences emerged, suggesting slower unwinding in female managers. Differences related to occupational level and/ or sex were found for autonomy and social support at work, competitiveness, sex role and reported conflict between demands from paid work and other responsibilities. The stress profile of the female managers was considered in terms of possible long-term health risks.     

Incorporating green-area user groups in urban ecosystem management

We analyze the role of urban green areas managed by local user groups in their potential for supporting biodiversity and ecosystem services in growing city-regions, with focus on allotment areas, domestic gardens, and golf courses. Using Stockholm, Sweden, as an example cityregion, we compile GIS data of its spatial characteristics and relate these data to GIS data for protected areas and "green wedges" prioritized in biodiversity conservation. Results reveal that the three land uses cover 18% of the studied land area of metropolitan Stockholm, which corresponds to more than twice the land set aside as protected areas. We review the literature to identify ecosystem functions and services provided by the three green areas and discuss their potential in urban ecosystem management. We conclude that the incorporation of locally managed lands, and their stewards and institutions, into comanagement designs holds potential for improving conditions for urban biodiversity, reducing transaction costs in ecosystem management, and realizing local Agenda 21.     

Deceptive behavior in pied flycatchers

Summary One explanation for polygyny in pied flycatchers (Ficedula hypoleuca) is the deception hypothesis, which proposes that females mate with already-mated males only because they are unaware that such males already have a mate on another territory. Recently this hypothesis has been criticized on the grounds that already-mated and unmated males differ sufficiently in their behavior that human observers can discriminate between the two classes fairly easily. Here we test whether male pied flycatchers change their behavior when visited by a female so as to make this discrimination more difficult. In our experiments we presented a caged female near the nestbox of an advertising male, in order to mimic the situation in which a female investigates the male and his nest site. During control periods, when only an empty cage was presented, we found that already-mated males were present on their secondary territories significantly less and sang significantly less than unmated males on their primary territories, confirming the earlier results. When we presented the stimulus female, all behaviors we measured changed significantly relative to control periods for both mated and unmated males: both classes of males increased the time spent on the territory, decreased singing rates, and increased various courtship behaviors. During the experimental periods there were no significant differences between mated and unmated males on any of the behavioral measures. Discriminant analysis was more successful in classifying males as to mating status using data from the control periods (without female) than using data from the experimental periods (with female). We conclude that when a female is present male pied flycatchers change their behavior in ways that make it more difficult to discriminate mated from unmated males.Offprint requests to: W.A. Searcy