Individual consistency in exploratory behaviour and mating tactics in male guppies

While behavioural plasticity is considered an adaptation to fluctuating social and environmental conditions, many animals also display a high level of individual consistency in their behaviour over time or across contexts (generally termed ‘personality’). However, studies of animal personalities that include sexual behaviour, or functionally distinct but correlated traits, are relatively scarce. In this study, we tested for individual behavioural consistency in courtship and exploratory behaviour in male guppies (Poecilia reticulata) in two light environments (high vs. low light intensity). Based on previous work on guppies, we predicted that males would modify their behaviour from sneak mating tactics to courtship displays under low light conditions, but also that the rank orders of courtship effort would remain unchanged (i.e. highly sexually active individuals would display relatively high levels of courtship under both light regimes). We also tested for correlations between courtship and exploratory behaviour, predicting that males that had high display rates would also be more likely to approach a novel object. Although males showed significant consistency in their exploratory and mating behaviour over time (1 week), we found no evidence that these traits constituted a behavioural syndrome. Furthermore, in contrast to previous work, we found no overall effect of the light environment on any of the behaviours measured, although males responded to the treatment on an individual-level basis, as reflected by a significant individual-by-environment interaction. The future challenge is to investigate how individual consistency across different environmental contexts relates to male reproductive success.     

Release from bats: genetic distance and sensoribehavioural regression in the Pacific field cricket, Teleogryllus oceanicus

The auditory thresholds of the AN2 interneuron and the behavioural thresholds of the anti-bat flight-steering responses that this cell evokes are less sensitive in female Pacific field crickets that live where bats have never existed (Moorea) compared with individuals subjected to intense levels of bat predation (Australia). In contrast, the sensitivity of the auditory interneuron, ON1 which participates in the processing of both social signals and bat calls, and the thresholds for flight orientation to a model of the calling song of male crickets show few differences between the two populations. Genetic analyses confirm that the two populations are significantly distinct, and we conclude that the absence of bats has caused partial regression in the nervous control of a defensive behaviour in this insect. This study represents the first examination of natural evolutionary regression in the neural basis of a behaviour along a selection gradient within a single species.     

Two pathways ensuring social harmony

Reproductive division of labour is a characteristic trait of social insects. The dominant reproductive individual, often the queen, uses chemical communication and/or behaviour to maintain her social status. Queens of many social insects communicate their fertility status via cuticle-bound substances. As these substances usually possess a low volatility, their range in queen–worker communication is potentially limited. Here, we investigate the range and impact of behavioural and chemical queen signals on workers of the ant Temnothorax longispinosus. We compared the behaviour and ovary development of workers subjected to three different treatments: workers with direct chemical and physical contact to the queen, those solely under the influence of volatile queen substances and those entirely separated from the queen. In addition to short-ranged queen signals preventing ovary development in workers, we discovered a novel secondary pathway influencing worker behaviour. Workers with no physical contact to the queen, but exposed to volatile substances, started to develop their ovaries, but did not change their behaviour compared to workers in direct contact to the queen. In contrast, workers in queen-separated groups showed both increased ovary development and aggressive dominance interactions. We conclude that T. longispinosus queens influence worker ovary development and behaviour via two independent signals, both ensuring social harmony within the colony.     

Behavioural and physiological consequences of male reproductive trade-offs in edible dormice (Glis glis)

Testosterone mediates male reproductive trade-offs in vertebrates including mammals. In male edible dormice (Glis glis), reproductivity linked to high levels of testosterone reduces their ability to express torpor, which may be expected to dramatically increase thermoregulatory costs. Aims of this study were therefore to analyse behavioural and physiological consequences of reproductive activity in male edible dormice under ecologically and evolutionary relevant conditions in the field. As we frequently encountered sleeping groups in the field, we hypothesized that social thermoregulation should be an important measure to reduce energy expenditure especially in sexually active male edible dormice. Our results revealed that the occurrence of sleeping groups was negatively influenced by male body mass but not by reproductive status or ambient temperature. In reproductive as in non-reproductive males, the number of individuals huddling together was negatively influenced by their body mass. Thus in general males with a high body mass were sitting in smaller groups than males with a low body mass. However, in reproductive males group size was further negatively affected by ambient temperature and positively by testes size. Thus breeders formed larger sleeping groups at lower ambient temperatures and males with larger testes were found in larger groups than males with smaller testes. Measurements of oxygen consumption demonstrated that grouping behaviour represents an efficient strategy to reduce energy expenditure in edible dormice as it reduced energy requirements by almost 40%. In summary, results of this field study showcase how sexually active male edible dormice may, through behavioural adjustment, counterbalance high thermoregulatory costs associated with reproductive activity.     

氟对斑马鱼生殖毒性研究

为了探讨氟对鱼类的生殖毒性效应,以成年斑马鱼为试验对象,氟化钠暴露45 d和90 d后,运用组织切片观察斑马鱼性腺组织的发育情况,采用酶联免疫分析法测定性腺中雌二醇（Estradiol,E2）、卵黄蛋白原（Vitellogenin,VTG）和睾酮（Testosterone,T）的含量,并使用实时荧光定量PCR方法检测斑马鱼生殖相关基因的表达水平.结果显示：氟暴露会阻滞成年斑马鱼性腺发育,造成卵泡发育不良,精巢生精能力下降;同时降低雌性斑马鱼性腺中E2和VTG的含量,增加T的含量;雌性斑马鱼孕酮受体（Prg）和糖皮质激素受体（GR）基因相对表达量随氟浓度的增加呈先降后升的趋势,随着染毒剂量与时间的增加,雄激素受体（AR）基因相对表达量逐渐增加,而CYP19a基因相对表达量逐渐减少.雄性斑马鱼性腺中E2、VTG、T的含量及生殖相关基因表达的变化趋势则与雌性斑马鱼相反.综上所述,氟暴露可以通过影响斑马鱼体内性腺发育、E2、VTG、T含量及生殖相关基因表达来影响其生殖功能.实验结果可为进一步研究氟化物对水生动物的生殖毒性效应提供理论依据.     

铅暴露对雄性黑斑蛙精子毒性和血清性激素水平的影响

在实验条件下,将健康性成熟雄性黑斑蛙暴露于0.1、0.2、0.4、0.8和1.6 mg·L-1浓度的铅溶液中30d,观察和分析黑斑蛙的精子数量、精子活动度和精子畸形率,采用酶联免疫吸附法检测血清中睾酮(T)和雌二醇(E2)的水平,以探讨铅对雄性黑斑蛙的生殖内分泌毒性.结果表明,随铅染毒剂量的升高,精子数量下降,精子畸形率呈剂鼍依赖性增加,精子活动率呈剂鼍依赖性降低;随铅染毒剂量的升高,血清中T水平明显下降,E2水平则明显升高,且均呈剂量-效应关系,结果提示,铅对雄性黑斑蛙有明显的生殖毒性,可改变血清睾酮和雌激素水平,干扰生殖内分泌调节平衡.     

壬基酚聚氧乙烯醚对成年雄性斑马鱼HPG轴相关基因表达的影响

本研究以模式动物斑马鱼（Danio rerio）为受试生物,采用半静态水体暴露的方式研究了不同浓度壬基酚聚氧乙烯醚（NPEO）对斑马鱼雄性成鱼下丘脑-垂体-性腺轴（HPG轴）的影响.结果显示,考察浓度范围内的NPEO暴露可以显著上调斑马鱼脑中GnRH2、GnRHR1、GnRHR2、GnRHR4、FSHβ和LHβ基因,以及性腺中LHR基因的相对表达量.GnRHR和LHR基因表达量对较低浓度NPEO暴露较为敏感,其中GnRHR4和LHR基因表达量在低至0.001mg/L的NPEO暴露下即出现显著上调.0.1和10mg/L NPEO暴露可以显著抑制斑马鱼精巢中CYP17基因的表达量,而10mg/L NPEO暴露则可以显著诱导CYP19a基因的表达量.GnRH相关调控基因表达量的上调,表明NPEO暴露可以诱导下丘脑分泌GnRH,进而刺激垂体分泌GtH.NPEO暴露诱导CYP19a基因的表达,促进了内源雌激素的合成.同时,NPEO通过抑制CYP17表达,可能抑制睾酮（T）的合成,干扰斑马鱼精巢中原有的性激素平衡.斑马鱼精巢内雌激素水平升高负反馈给垂体,刺激垂体分泌促性腺激素.由此表明,考察浓度范围内（0.001~10mg/L）的NPEO的暴露可以影响雄性斑马鱼成鱼HPG轴的反馈调节.     

Social familiarity modulates group living and foraging behaviour of juvenile predatory mites

Environmental stressors during early life may have persistent consequences for phenotypic development and fitness. In group-living species, an important stressor during juvenile development is the presence and familiarity status of conspecific individuals. To alleviate intraspecific conflicts during juvenile development, many animals evolved the ability to discriminate familiar and unfamiliar individuals based on prior association and use this ability to preferentially associate with familiar individuals. Assuming that familiar neighbours require less attention than unfamiliar ones, as predicted by limited attention theory, assorting with familiar individuals should increase the efficiency in other tasks. We assessed the influence of social familiarity on within-group association behaviour, development and foraging of juvenile life stages of the group-living, plant-inhabiting predatory mite Phytoseiulus persimilis. The observed groups consisted either of mixed-age familiar and unfamiliar juvenile mites or of age-synchronized familiar or unfamiliar juvenile mites or of pairs of familiar or unfamiliar larvae. Overall, familiar mites preferentially grouped together and foraged more efficiently, i.e. needed less prey at similar developmental speed and body size at maturity, than unfamiliar mites. Preferential association of familiar mites was also apparent in the inter-exuviae distances. Social familiarity was established by imprinting in the larval stage, was not cancelled or overridden by later conspecific contacts and persisted into adulthood. Life stage had an effect on grouping with larvae being closer together than nymphal stages. Ultimately, optimized foraging during the developmental phase may relax within-group competition, enhance current and future food supply needed for optimal development and optimize patch exploitation and leaving under limited food.     

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.     

Primate Socioecology: New Insights from Males

Primate males have only recently returned to the center stage of socioecological research. This review surveys new studies that examine variation in the behavior of adult males and their role in social evolution. It is shown that group size, composition, and social behavior are determined not only by resource distribution, predation risk, and other ecological factors, but that life history traits and social factors, especially those related to sexual coercion, can have equally profound consequences for social systems. This general point is illustrated by examining male behavior at three levels: the evolution of permanent associations between males and females, the causes and consequences of variation in the number of males between group-living species, and the determinants of social relationships within and between the sexes. Direct and indirect evidence reviewed in connection with all three questions indicates that the risk of infanticide has been a pervasive force in primate social evolution. Several areas are identified for future research on male life histories that should contribute to a better understanding of male reproductive strategies and corresponding female counter-strategies.     

荒漠河岸多枝柽柳灌丛碳氮磷化学计量特征及其影响因素

为了解群落水平下荒漠河岸多枝柽柳（Tamarix ramosissima Ledeb.）灌丛的碳氮磷化学计量特征及其影响因素,在黑河下游荒漠河岸3 800 m范围内,沿垂直河道方向上设置9个采样点,采用相关性分析、冗余分析（RDA）和偏冗余分析（pRDA）方法,对多枝柽柳群落的碳氮磷化学计量格局及其与环境因子的关系进行研究.结果表明:黑河下游荒漠河岸多枝柽柳群落TC、TN、TP含量平均值分别为380.27、30.42和1.54 mg/g,C:N、C:P和N:P平均值分别为12.98、257.09和20.04.与全球和区域尺度物种水平研究相比,黑河下游荒漠河岸多枝柽柳灌丛群落具有较低的TC含量、较高的TN含量和N:P以及相对稳定的TP含量.多枝柽柳灌丛群落碳氮磷化学计量特征变异系数相对较小,内稳性较强,相对较高的N:P（14.55~27.20）表明群落水平下多枝柽柳灌丛更倾向于受磷元素的限制.在沿河梯度上,多枝柽柳群落TC含量和TN含量均随沿河距离的增加呈显著下降的变化趋势,而C:N随沿河距离的增加呈波动上升的变化趋势;TP含量呈先降后升的变化趋势,而C:P和N:P大致呈先上升后下降的变化趋势.多枝柽柳灌丛群落的碳氮磷化学计量特征与土壤理化属性存在一定相关性,土壤含水量、土壤容重和土壤pH是影响多枝柽柳群落碳氮磷化学计量特征变化的关键因子,三者共同解释了总变异的57.7%,其中土壤含水量解释了总变异的32.8%.研究显示,土壤水盐与多枝柽柳灌丛的碳氮磷化学计量特征关系密切,土壤含水量在解释多枝柽柳灌丛碳氮磷化学计量特征变化方面比土壤pH更为重要.      

成渝城市群碳排放空间关联结构演化及影响因素

本文基于社会网络分析法（SNA）以及二次分配程序（QAP）方法,利用成渝城市群2005~2016年面板数据,对成渝城市群碳排放空间关联性及影响因素进行研究.结果表明：①成渝城市群碳排放空间关联性显著,呈现出复杂的网络结构形态,样本期内,网络密度由0.16增长至0.68,关联关系数从38个增长为162个.②重庆、成都、绵阳和南充等城市位于网络的中心地位,发出了较多的关联关系,同时发挥着中介作用.③碳排放空间关联网络被划分成为5个层级,层级结构整体较为稳定,然而第一层级与第二层级存在较为严重的断层现象.④空间距离、人口数量差异以及经济水平差异是碳排放关联性的主要驱动因素.城市间空间距离越近、人口数量与经济水平差异越大,越容易产生碳排放关联关系.     

Gonadotropic effects of dopamine in isolated workers of the primitively eusocial wasp, Polistes chinensis

In social insects, biogenic amines are thought to play regulatory roles in the transition between reproductive states in females. To determine the effect of dopamine on the reproductive development of workers in primitively eusocial societies, isolated workers of the paper wasp Polistes chinensis were supplied with oral dopamine. Ovarian development was accelerated in dopamine-fed workers as compared to control workers of the same age fed only sucrose solution. Oral dopamine increased brain levels of dopamine and its metabolite (N-acetyldopamine). Brain levels of tyramine or octopamine were also increased by dopamine application in one of two colonies; levels of the tyramine metabolite N-acetyltyramine were unchanged. These results indicate that dopamine plays a gonadotropic role in isolated workers in the primitively eusocial wasp, similar to the gonadotropic role previously reported for juvenile hormone. This is the first study to report effects of dopamine on ovarian development in workers of the paper wasp.     

David and Goliath: potent venom of an ant-eating spider (Araneae) enables capture of a giant prey

It is rare to find a true predator that repeatedly and routinely kills prey larger than itself. A solitary specialised ant-eating spider of the genus Zodarion can capture a relatively giant prey. We studied the trophic niche of this spider species and investigated its adaptations (behavioural and venomic) that are used to capture ants. We found that the spider captures mainly polymorphic Messor arenarius ants. Adult female spiders captured large morphs while tiny juveniles captured smaller morphs, yet in both cases ants were giant in comparison with spider size. All specimens used an effective prey capture strategy that protected them from ant retaliation. Juvenile and adult spiders were able to paralyse their prey using a single bite. The venom glands of adults were more than 50 times larger than those of juvenile spiders, but the paralysis latency of juveniles was 1.5 times longer. This suggests that this spider species possesses very potent venom already at the juvenile stage. Comparison of the venom composition between juvenile and adult spiders did not reveal significant differences. We discovered here that specialised capture combined with very effective venom enables the capture of giant prey.     

On the significance of adult play: what does social play tell us about adult horse welfare?

Play remains a mystery and adult play even more so. More typical of young stages in healthy individuals, it occurs rarely at adult stages but then more often in captive/domestic animals, which can imply spatial, social and/or feeding deprivations or restrictions that are challenging to welfare, than in animals living in natural conditions. Here, we tested the hypothesis that adult play may reflect altered welfare states and chronic stress in horses, in which, as in several species, play rarely occurs at adult stages in natural conditions. We observed the behaviour (in particular, social play) of riding school horses during occasional outings in a paddock and measured several stress indicators when these horses were in their individual home boxes. Our results revealed that (1) the number of horses and rates of adult play appeared very high compared to field report data and (2) most stress indicators measured differed between ‘players’ and ‘non-players’, revealing that most ‘playful’ animals were suffering from more chronic stress than ‘non-playful’ horses. Frequency of play behaviour correlated with a score of chronic stress. This first discovery of a relationship between adult play and altered welfare opens new lines of research that certainly deserves comparative studies in a variety of species.     

淹水对菖蒲(Acorus calamus)根际氧环境的影响

为研究淹水对湿地植物根际氧环境的影响,选择典型湿地植物菖蒲幼苗(株高约15 cm、根长约6 cm)和成株(株高约40 cm、根长约11 cm)在沉积物中培养并完全淹没,利用微型电机控制氧气微光极对菖蒲根中部根际氧浓度及组织内部氧浓度原位测定3周. 结果表明:短期(7 d) 淹水,菖蒲幼苗及成株根际氧扩散层厚度及氧浓度比对照组均显著下降;在淹水第14天,在幼苗根际未检出氧扩散层;在淹水第21天,成株根际氧扩散层厚度及平均氧浓度仍分别为0.34 mm和11.18%,并保持至淹水试验结束. 淹水组菖蒲的根际氧扩散层厚度、平均氧浓度均随根组织内部氧浓度的下降而降低,其中幼苗3个指标分别由初始的0.22 mm、1.4%和50.3%降至0 mm、0%和32.9%,成株分别由0.64 mm、19.3%和64.6%降至0.34 mm、11.2%和55.3%,表明前2个指标的下降程度显著超过后者;淹水组菖蒲幼苗、成株根组织内部氧浓度主要受植株光合作用的影响,而对照组则受光合作用及气体交换作用的共同影响,淹水能在短期(7 d)内促进菖蒲成株根通气组织的发育,使其孔隙率从28.45%升至32.44%,并有助于维持根组织内的氧浓度水平,根组织内部氧浓度淹水组(65.6%)与对照组(67.1%)无显著差异. 研究表明,淹水胁迫下,根组织内部氧浓度水平是影响菖蒲根氧扩散的核心因素,其中幼苗根组织内部氧浓度显著下降并威胁到自身存活时,其已无氧扩散效应,而成株根组织内部较高的氧浓度使其仍能保持一定程度的氧扩散.      

Assessing cypermethrin-contaminated soil with three di erent earthworm test methods

A series of tests (lethal, sublethal, and behavioral) on earthworms were conducted as an eco-assessment of pesticides. In this study, the toxicity of cypermethrin-contaminating soil on adult and juvenile earthworms was assessed. Beside the acute and chronic tests, an avoidance response test was carried out. It was shown that the all-round toxicity from cypermethrin was weak on adult earthworms. Compared with adult earthworms, the toxicity of juvenile earthworms from cypermethrin especially chronic toxicity increased significantly. Growth and reproduction of earthworms appeared to be more severely a ected by cypermethrin at juvenile stage than at adult stage. Applied at 10 mg/kg, cypermethrin had obvious adverse impact on the growth of juvenile earthworms, while 20 mg/kg, cypermethrin caused significant toxic e ects in reproduction. The results also indicated that ecotoxicological risk assessment using only adult specimens may underestimate the e ects of cypermethrin on soil invertebrate populations.     

Communally breeding bats use physiological and behavioural adjustments to optimise daily energy expenditure

Small endotherms must change roosting and thermoregulatory behaviour in response to changes in ambient conditions if they are to achieve positive energy balance. In social species, for example many bats, energy expenditure is influenced by environmental conditions, such as ambient temperature, and also by social thermoregulation. Direct measurements of daily fluctuations in metabolic rates in response to ambient and behavioural variables in the field have not been technologically feasible until recently. During different reproductive periods, we investigated the relationships between ambient temperature, group size and energy expenditure in wild maternity colonies of Bechstein’s bats (Myotis bechsteinii). Bats used behavioural and physiological adjustments to regulate energy expenditure. Whether bats maintained normothermia or used torpor, the number of bats in the roosts as well changed with reproductive status and ambient temperature. During pregnancy and lactation, bats remained mostly normothermic and daily group sizes were relatively large, presumably to participate in the energetic benefits of social thermoregulation. In contrast, smaller groups were formed on days when bats used torpor, which occurred mostly during the post-lactation period. Thus, we were able to demonstrate on wild animals under natural conditions the significance of behavioural and physiological flexibility for optimal thermoregulatory behaviour in small endotherms.     

Can community-based governance strengthen citizenship in support of climate change adaptation? Testing insights from Self-Determination Theory

Motivation plays a powerful role in guiding human decision-making and behaviour, including adaptation to climate change. This study aimed to determine whether community-based governance would increase behavioural support, in the form of donation behaviour, for a climate change adaptation trust fund. A sample of 548 Australians was randomly assigned to view one of two governance scenarios: (1) a community-based scenario in which community members were afforded a high level of autonomy in designing and allocating funding within a trust fund to help their community adapt to climate change, or (2) a government-centred scenario in which decision making regarding the trust fund remained with government officials. Path analysis revealed that the community-based scenario produced significantly higher levels of perceived autonomy support within the study’s participants. High levels of perceived autonomy support predicted higher levels of autonomous motivation (indicating stronger citizenship) and lower levels of amotivation, a motivational pattern, which, in turn, predicted greater willingness to donate to the climate change adaptation trust. Results are interpreted in terms of Self-Determination Theory and Motivational Crowding Theory.     

Mate guarding and territorial aggression vary with breeding synchrony in golden whistlers (<Emphasis Type="Italic">Pachycephala pectoralis</Emphasis>)

Male paternity assurance behaviour during the female fertile period has been widely documented amongst birds. In contrast, how sex-specific behavioural strategies vary with local breeding synchrony levels remains largely unknown. This is important because, in many species, intra-population patterns of extra-pair fertilisation rates, and hence cuckoldry risk, are known to vary with the number of simultaneously fertile females. Each sex may therefore differ in how they behave towards male conspecifics during different degrees of breeding synchrony. Here I provide evidence of such sex-specific differences in the golden whistler (Pachycephala pectoralis), a species in which within-pair paternity assurance is negatively associated with breeding synchrony. Via simulated territorial intrusions using decoy males, I show that males, but not females, increase levels of aggression to male intruders during periods of low synchrony, possibly because cuckoldry risk is greatest during this period. In addition, males appear to invest more effort into mate guarding after, but not before, territorial intrusions during this period. These inter-sexual differences may reflect conflicts in interest between the sexes, with females consistently showing interest in males during the fertile period regardless of synchrony levels and males investing more resources into expelling intruders when the risk of paternity loss is greatest. This study thus provides evidence that males may be able to detect variation in breeding synchrony and cuckoldry risk and adjust their paternity assurance behaviour accordingly.