<Emphasis Type="Italic">Drosophila melanogaster</Emphasis> virgins are more likely to mate with strangers than familiar flies

Recent evidence shows that females of many species can discriminate against males and/or male phenotypes they have mated with previously. However, these studies have not tested whether actual mating is necessary to induce the avoidance behaviour. A preference for strangers may have evolved because it avoids multiple matings with similar genotypes. Alternatively, there may be selection against mating with familiar individuals directly. By choosing its first mate among unfamiliar individuals (which are less likely close relatives than are those encountered early in life), a virgin might disentangle some of the potential benefits of avoiding genetic incompatibility and inbreeding in the offspring from the costs of remating. In this study, we test whether Drosophila melanogaster flies bias their mate choice towards strangers according to previous, non-copulatory, experience. Based on 173 trials over 12 weeks, virgin females presented with two virgin males were 59% more likely to mate with a novel male than the one which she had been housed with for 8 h the day before. Hence we present the first report showing that a dipteran can distinguish between previously encountered and not previously encountered conspecifics.     

Levels of behavioral organization and the evolution of division of labor

The major features of insect societies that fascinate biologists are the self-sacrificing altruism expressed by colony members, the complex division of labor, and the tremendous plasticity demonstrated in the face of changing environments. The social behavior of insects is a result of complex interactions at different levels of biological organization. Genes give rise to proteins and peptides that build the nervous and muscular systems, regulate their own synthesis, interact with each other, and affect the behavior of individuals. Social behavior emerges from the complex interactions of individuals that are themselves far removed from the direct effects of the genes. In order to understand how social organization evolves, we must understand the mechanisms that link the different levels of organization. In this review, we discuss how behavior is influenced by genes and the neural system and how social behavior emerges from the behavioral activities of individuals. We show how different levels of organization share common features and are linked through common mechanisms. We focus on the behavior of the honey bee, the best studied of all social insects.     

Nuisance arthropods, nonhost odors, and vertebrate chemical aposematism

Mosquitoes, ticks, and other ectoparasitic arthropods use chemoreception to avoid vertebrates that are known or presumed to be dangerous or otherwise unprofitable hosts. Nonhosts may belong to a species that is regularly unaccepted or one that includes both accepted and unaccepted individuals. A diverse array of qualities including immunocompetence, vigilant grooming behavior, mechanical inaccessibility, and toxicity have been proposed as the features that render vertebrate chemical emitters unsuitable as hosts for arthropods. In addition to advantages accrued by ectoparasitic arthropods that avoid nonhosts, vertebrates that are not accepted as hosts benefit by evading injurious ectoparasites and the infectious agents they transmit. The conferral of advantages to both chemical receivers (ectoparasitic arthropods) and emitters (unpreferred vertebrates) in these interactions renders nonhost odors aposematic. Chemical aposematism involving ectoparasites selects for vertebrates that emit distinctive odors. In addition, chemical mimicry, where vulnerable organisms benefit when misidentified as nonhosts, may be accommodated by duped ectoparasites.     

Spectacular Batesian mimicry in ants

The mechanism by which palatable species take advantage of their similarity in appearance to those that are unpalatable, in order to avoid predation, is called Batesian mimicry. Several arthropods are thought to be Batesian mimics of social insects; however, social insects that are Batesian mimics among themselves are rare. In Malaysia we found a possible Batesian mimic in an arboreal ant species, Camponotus sp., which was exclusively observed on foraging trails of the myrmicine ant Crematogaster inflata. The bright yellow and black colouring pattern, as well as the walking behaviour, were very similar in both species. We observed general interactions between the two species, and tested their palatability and the significance of the remarkably similar visual colour patterns for predator avoidance. Prey offered to C. inflata was also eaten by Camponotus workers in spite of their being attacked by C. inflata, indicating that Camponotus sp. is a commensal of C. inflata. An experiment with chicks as potential predators suggests that Camponotus sp. is palatable whereas C. inflata is unpalatable. After tasting C. inflata, the chicks no longer attacked Camponotus sp., indicating that Camponotus sp. is a Batesian mimic of Crematogaster inflata.     

The Potential of Brazil's Forest Sector for Mitigating Global Warming under the Kyoto Protocol

Activities in Brazil's forest sector have substantial potential for mitigating global warming as well as additional environmental and other benefits. Silvicultural plantations of different types, reduced impact logging, and deforestation avoidance all have potential mitigation roles. The magnitude of the annual emission from recent rates of deforestation in Amazonia presents an opportunity for carbon (C) benefits through reducing current rates of deforestation. Measures related to Amazonian deforestation have greater potential carbon benefits than do options such as plantation silviculture, but much depends on how benefits are calculated. Procedures are needed for assessing the environmental and social impacts of Clean DevelopmentMechanism (CDM) projects.     

Participation in devolved commons management: Multiscale socioeconomic factors related to individuals’ participation in community-based management of marine protected areas in Indonesia

Management of common-pool natural resources is commonly implemented under institutional models promoting devolved decision-making, such as co-management and community-based management. Although participation of local people is critical to the success of devolved commons management, few studies have empirically investigated how individuals’ participation is related to socioeconomic factors that operate at multiple scales. Here, we evaluated how individual- and community-scale factors were related to levels of individual participation in management of community-based marine protected areas in Indonesia. In addressing this aim, we drew on multiple bodies of literature on human behaviour from economics and social science, including the social-ecological systems framework from the literature on common-pool resources, the theory of planned behaviour from social psychology, and public goods games from behavioural economics. We found three key factors related to level of participation of local people: subjective norms, structural elements of social capital, and nested institutions. There was also suggestive evidence that participation was related to people’s cooperative behavioural disposition, which we elicited using a public goods game. These results point to the importance of considering socioeconomic factors that operate at multiple scales when examining individual behaviour. Further, our study highlights the need to consider multiscale mechanisms other than those designed to appeal to self-interested concerns, such as regulations and material incentives, which are typically employed in devolved commons management to encourage participation. Increased understanding of the factors related to participation could facilitate better targeting of investments aimed at encouraging cooperative management.     

Vulnerability and behavioral response to ultraviolet radiation in the components of a foliar mite prey–predator system

Ambient ultraviolet-B (UVB) radiation impacts plant-dwelling arthropods including herbivorous and predatory mites. However, the effects of UVB on prey?Cpredator systems, such as that between the herbivorous spider mite and predatory phytoseiid mite, are poorly understood. A comparative study was conducted to determine the vulnerability and behavioral responses of these mites to ultraviolet (UV) radiation. First, we analyzed dose?Cresponse (cumulative irradiance-mortality) curves for the eggs of phytoseiid mites (Neoseiulus californicus, Neoseiulus womersleyi, and Phytoseiulus persimilis) and the spider mite (Tetranychus urticae) to UVB radiation from a UV lamp. This indicated that the phytoseiid mites were more vulnerable than the spider mite, although P. persimilis was slightly more tolerant than the other two phytoseiid mites. Second, we compared the avoidance behavior of adult female N. californicus and two spider mite species (T. urticae, a lower leaf surface user; Panonychus citri, an upper leaf surface user) in response to solar UV and visible light. N. californicus actively avoided both types of radiation, whereas P. citri showed only minimal avoidance behavior. T. urticae actively avoided UV as well as N. californicus but exhibited a slow response to visible light as well as P. citri. Such variation in vulnerability and avoidance behavior accounts for differences in the species adaptations to solar UVB radiation. This may be the primary factor determining habitat use among these mites on host plant leaves, subsequently affecting accessibility by predators and also intraguild competition.     

Of Domestic and Wild Guinea Pigs: Studies in Sociophysiology, Domestication, and Social Evolution

Cavia aperea   and Galea musteloides) and domestic (Cavia aperea f. porcellus) guinea pigs, which summarizes general rules for many group-living mammals. It is shown that social interactions have consequences not only for the individuals' reproductive success but also for their degrees of stress and welfare. The way in which individuals interact is controlled not only by the present environment but also by the previous social experiences which they have gathered during their behavioral development. Furthermore, the study of ontogeny does not begin at birth, because prenatal social factors acting on pregnant females can also affect the way in which the offspring will interact when adult. In addition, to understand the genesis of interactions between domesticated animals implies knowledge of the behavioral and physiological changes which occurred during the process of domestication. Finally, understanding the social interactions among individuals of the wild ancestor of the domesticated form requires knowledge of how their behavior patterns were brought about by natural selection during the process of social evolution.     

The effectiveness of flood risk communication strategies and the influence of social networks—Insights from an agent-based model

Flood risk management is becoming increasingly important, because more people are settling in flood-prone areas, and flood risk is increasing in many regions due to extreme weather events associated with climate change. It has been proposed that appropriately designed flood risk communication campaigns can stimulate floodplain inhabitants to prepare for flooding, and encourage adaptation to climate change. However, such campaigns do not always result in the desired action, and the effectiveness of communication in raising flood risk awareness and improving flood preparedness has hardly been studied. We evaluate different flood risk communication strategies, using an agent-based modelling approach, which is especially suitable for examining the effect of communication on each individual, and how flood risk communication can propagate through an individual’s social network. Our modelling results show that tailored, people-centred, flood risk communication can be significantly more effective than the common approach of top-down government communication, even when tailored communication reaches fewer individuals. Furthermore, communication on how to protect against floods, in addition to providing information about flood risk, is much more effective than the traditional strategy of communicating only about flood risk. Another main finding is that a person’s social network can have a significant effect on whether or not individuals take protective action. This leads to the recommendation that flood risk communication should aim at exploiting this natural amplifying effect of social networks, for instance, through the use of social media.     

Alarm communication: a new function for the scent-gland secretion in harvestmen (Arachnida: Opiliones)

Most harvestmen are nocturnal, nonacoustical, and nonvisual arthropods. They have a pair of exocrine glands on the cephalothorax that produce defensive volatile secretions. We investigated in the field the possible alarm effect of these secretions in the gregarious harvestman Goniosoma aff. proximum. A cotton swab soaked with the species' own exudate (treatment), or with water (control), was held 1-2 cm from the center of harvestmen aggregations. The results showed that the gland secretion elicits an alarm response in Goniosoma: whereas 73.3% of the aggregations dispersed after being stimulated with the gland exudate, only 3.3% responded to the water control. Respondent groups are larger than nonrespondent groups, and the time of reaction to the secretion was inversely related to group size. This is the first demonstration of a chemically-mediated alarm effect in harvestmen. The alarm response in gregarious harvestmen has possibly evolved as a by-product of a primarily defensive reaction in the context of predator avoidance. The discovery of this novel function of scent-gland secretion is meaningful in view of the widespread occurrence of gregarious habit among species of the order Opiliones.     

Side biases in humans (Homo sapiens): three ecological studies on hemispheric asymmetries

Hemispheric asymmetries and side biases have been studied in humans mostly in laboratory settings, and evidence obtained in naturalistic settings is scarce. We here report the results of three studies on human ear preference observed during social interactions in noisy environments, i.e., discotheques. In the first study, a spontaneous right-ear preference was observed during linguistic exchange between interacting individuals. This lateral bias was confirmed in a quasi-experimental study in which a confederate experimenter evoked an ear-orienting response in bystanders, under the pretext of approaching them with a whispered request. In the last study, subjects showed a greater proneness to meet an experimenter’s request when it was directly addressed to the right rather than the left ear. Our findings are in agreement both with laboratory studies on hemispheric lateralization for language and approach/avoidance behavior in humans and with animal research. The present work is one of the few studies demonstrating the natural expression of hemispheric asymmetries, showing their effect in everyday human behavior.     

Social spiders of the genus Anelosimus occur in wetter, more productive environments than non-social species

Latitude, rainfall, and productivity have been shown to influence social organisation and level of sociality in arthropods on large geographic scales. Social spiders form permanent group-living societies where they cooperate in brood care, web maintenance, and foraging. Sociality has evolved independently in a number of unrelated spider genera and may reflect convergent evolutionary responses to common environmental drivers. The genus Anelosimus contains a third of approximately 25 described permanently social spider species, eight to nine species that all occur in the Americas. To test for environmental correlates of sociality in Anelosimus across the Americas, we used logistic regression to detect effects of annual rainfall, productivity, and precipitation seasonality on the relative likelihood of occurrence of social and non-social Anelosimus spiders. Our analyses show that social species tend to occur at higher annual rainfall and productivity than non-social species, supporting the hypothesised effects of these environmental variables on the geographical distribution of social species. We did not find support for the hypothesis that permanently social species occur in areas with low precipitation seasonality. High annual precipitation and, to less extent, high productivity favour the occurrence of permanently group-living Anelosimus spiders relative to subsocial and solitary species. These results are partially consistent with previous findings for the Old World spider genus Stegodyphus, where a link between high habitat productivity and sociality was also found. Unlike Anelosimus, however, Stegodyphus typically occur in dry habitats negating a general importance of high precipitation for sociality. Sociality in spiders thus seems to be strongly linked to productivity, probably reflecting the need for relatively high availability of large prey to sustain social colonies.     

Early succession arthropod community changes on experimental passion fruit plant patches along a land-use gradient in Ecuador

Many tropical landscapes are today characterized by small forest patches embedded in an agricultural mosaic matrix. In such highly fragmented landscapes, agroforests have already been recognized as refuges for biodiversity but few studies have investigated the potential of non-forested land-use types to contribute to overall biodiversity of functionally important taxa in the tropics. This study experimentally investigated species richness, abundance, and community similarity of arthropods on Yellow Passion fruit plants, planted in standardized patches in 30 sites along a land-use intensity gradient. The gradient comprised all major land-use types of the area: forest fragments, abandoned coffee agroforests, coffee agroforests managed under shade trees, pastures, and rice fields in Coastal Ecuador. We found a total of 2123 individuals belonging to 242 species. Overall arthropod species richness increased with light intensity and leaf-surface area and decreased with land-use intensity: forest fragments and abandoned coffee agroforests harboured significantly more species than rice or pastures. Overall diversity in managed coffee agroforests was intermediate between the intensively managed and more natural habitats. However, the three most abundant taxa of arthropods (ants, spiders, and beetles) had the highest number of species in managed coffee agroforests, while ant abundance was highest in abandoned coffee agroforests and spider abundance highest in managed coffee agroforests. Analyses of community similarity revealed that open (pasture, and rice) and shaded (forest, abandoned and managed coffee agroforests) land-use types had distinct arthropod communities. In conclusion, although open agricultural land-use types tend to have fewer species in lower numbers, all land-use types contribute to overall biodiversity of the agricultural matrix because of distinct communities in shaded vs. non-shaded land-use types.     

Virgin ant queens mate with their own sons to avoid failure at colony foundation

Mother–son mating (oedipal mating) is practically non-existent in social Hymenoptera, as queens typically avoid inbreeding, mate only early in life and do not mate again after having begun to lay eggs. In the ant genus Cardiocondyla mating occurs among sib in the natal nests. Sex ratios are extremely female-biased and young queens face the risk of remaining without mating partners. Here, we show that virgin queens of Cardiocondyla argyrotricha produce sons from their own unfertilized eggs and later mate with them to produce female offspring from fertilized eggs. Oedipal mating may allow C. argyrotricha queens to found new colonies when no mating partners are available and thus maintains their unusual life history combining monogyny, mating in the nest, and low male production. Our result indicates that a trait that sporadically occurs in solitary haplodiploid animals may evolve also in social Hymenoptera under appropriate ecological and social conditions.     

Reduced population size does not affect the mating strategy of a vulnerable and endemic seabird

Bottleneck episodes may occur in small and isolated animal populations, which may result in decreased genetic diversity and increased inbreeding, but also in mating strategy adjustment. This was evaluated in the vulnerable and socially monogamous Monteiro’s Storm-petrel Hydrobates monteiroi, a seabird endemic to the Azores archipelago which has suffered a dramatic population decline since the XVth century. To do this, we conducted a genetic study (18 microsatellite markers) in the population from Praia islet, which has been monitored over 16 years. We found no evidence that a genetic bottleneck was associated with this demographic decline. Monteiro’s Storm-petrels paired randomly with respect to genetic relatedness and body measurements. Pair fecundity was unrelated to genetic relatedness between partners. We detected only two cases of extra-pair parentage associated with an extra-pair copulation (out of 71 offspring). Unsuccessful pairs were most likely to divorce the next year, but genetic relatedness between pair mates and pair breeding experience did not influence divorce. Divorce enabled individuals to improve their reproductive performances after re-mating only when the new partner was experienced. Re-pairing with an experienced partner occurred more frequently when divorcees changed nest than when they retained their nest. This study shows that even in strongly reduced populations, genetic diversity can be maintained, inbreeding does not necessarily occur, and random pairing is not risky in terms of pair lifetime reproductive success. Given, however, that we found no clear phenotypic mate choice criteria, the part played by non-morphological traits should be assessed more accurately in order to better understand seabird mating strategies.     

Feminization of genetic males by a symbiotic bacterium in a butterfly,Eurema hecabe (Lepidoptera: Pieridae)

Wolbachia are symbiotic bacteria found in many arthropods and filarian nematodes. They often manipulate the reproduction of host arthropods. In the present study, female-biased sex-ratio distortion in the butterfly Eurema hecabe was investigated. Breeding experiments showed that this distorted sex ratio is maternally inherited. When treated with tetracycline, adult females of the thelygenic line produced male progeny only. After PCR using Wolbachia-specific primers for the ftsZ gene a positive result was seen in the thelygenic females, but not in male progeny from tetracycline-treated females, or individuals from a Tokyo population with normal sex ratio and reproduction. Cytological observations showed that thelygenic females lack the sex chromatin body (W chromosome). The results strongly suggest that the sex-ratio distortion in E. hecabe is due to feminization of genetic males by Wolbachia.     

我国环境影响评价审查的专家回避制度探讨

对我国环境影响评价专家审查制度存在的问题进行深入分析,参考我国司法、行政、仲裁体系的回避制度,探讨如何以《环境影响评价审查专家库管理办法》中的审查专家主动回避规定为基础,引入审查专家申请回避,建立、健全我国环境影响评价审查的专家回避制度,以保证环境影响评价审查的公正性、公平性和权威性,进一步完善我国的环境影响评价制度。     

Multilevel selection and social evolution of insect societies

How sterile, altruistic worker castes have evolved in social insects and how they are maintained have long been central topics in evolutionary biology. With the advance of kin selection theory, insect societies, in particular those of haplodiploid bees, ants, and wasps, have become highly suitable model systems for investigating the details of social evolution and recently also how within-group conflicts are resolved. Because insect societies typically do not consist of clones, conflicts among nestmates arise, for example about the partitioning of reproduction and the allocation of resources towards male and female sexuals. Variation in relatedness among group members therefore appears to have a profound influence on the social structure of groups. However, insect societies appear to be remarkably robust against such variation: division of labor and task allocation are often organized in more or less the same way in societies with high as in those with very low nestmate relatedness. To explain the discrepancy between predictions from kin structure and empirical data, it was suggested that constraints—such as the lack of power or information—prevent individuals from pursuing their own selfish interests. Applying a multilevel selection approach shows that these constraints are in fact group-level adaptation preventing or resolving intracolonial conflict. The mechanisms of conflict resolution in insect societies are similar to those at other levels in the biological hierarchy (e.g., in the genome or multicellular organisms): alignment of interests, fair lottery, and social control. Insect societies can thus be regarded as a level of selection with novelties that provide benefits beyond the scope of a solitary life. Therefore, relatedness is less important for the maintenance of insect societies, although it played a fundamental role in their evolution.Dedicated to Prof. Ernst Mayr     

Yellowjackets (Vespula pensylvanica) thermoregulate in response to changes in protein concentration

Social insects can modulate body temperature to increase foraging efficiency; however, little is known about how the relative value of protein resources affects forager body temperature. Such regulation may be important given that colony growth is often limited by protein availability. In this paper, we present what are, to our knowledge, the first data for social insects showing that thoracic temperatures (T (th)) of foragers increase with the protein content of food resources. In an introduced population of western yellowjacket (Vespula pensylvanica), we measured T (th) of foragers collecting high-quality protein (100% canned chicken) and low-quality protein (50% canned chicken, 50% indigestible alpha-cellulose by volume) at different ambient air temperatures (T (a)). Wasps foraging on 100% chicken consistently exhibited higher T (th) compared to wasps foraging on 50% chicken. After correcting for T (a), the mean T (th) for wasps collecting 100% chicken were 1.98 degrees C higher than those of individuals collecting 50% chicken. We suggest that this mechanism may increase foraging efficiency in this and other social wasp species.     

Mutualistic Benefits Generate an Unequal Distribution of Risky Activities Among Unrelated Group Members

Recent studies provide a new challenge to the adequacy of theories concerning the evolution of cooperation among nonrelatives: some individuals perform high-risk activities while others do not. We examined a communal hymenopteran species, Lasioglossum (Chilalictus) hemichalceum, to determine why group members engaged in demonstrably risky activities (foraging) tolerate the selfish behavior (remaining in the nest) of unrelated nestmates. Experimental removal of adult females indicated that their presence is required for the protection of brood from ant predators. Nonforagers ensure the continued presence of adults in the nest if the risk-taking foragers die, thereby safeguarding the survival of forager offspring. This results in an unequal distribution of risky activities within social groups in which avoidance of risky activities by some group members is ultimately beneficial to risk takers. Received: 10 June 1997 / Accepted in revised form: 25 May 1998