Sperm traits in the quacking frog (<Emphasis Type="Italic">Crinia georgiana</Emphasis>), a species with plastic alternative mating tactics

In species where males use alternative reproductive tactics and male phenotypes are confronted with different risks of sperm competition, theory predicts that between-male-type differences in sperm expenditure may evolve. In the frog Crinia georgiana big males can monopolize females, whereas small males often engage in polyandrous matings. Consequently, big males may experience a lower risk of sperm competition than do small males. We tested if the predictions from theoretical models can be applied to the mating system of C. georgiana. Our results showed that small males do not have larger testes relative to their body size compared to their larger counterparts and that the efficiency with which sperm number, size, motility, and longevity are produced by the testes does not differ between small and large males in the predicted way. These results are not in alignment with predictions from a loaded raffle model of sperm competition on sperm expenditure in males with alternative phenotypes. The plasticity in mating tactics used by C. georgiana males and a high intraseasonal variation in male densities may have prevented the evolution of enhanced sperm performance in smaller males. A fair raffle in the sperm competition game played by C. georgiana males could also explain the observed patterns in sperm traits. Future investigations determining the parameters responsible for the deviation from theoretical predictions in this system will test the degree to which current theoretical models can indeed be applied to species with plastic reproductive tactics.     

中国工业碳排放的因素分解与脱钩效应

采用广义迪氏指数分解法（GDIM）分析2000~2016年中国工业碳排放的驱动因素,并在此基础上,创新性地结合DPSIR框架构建脱钩努力模型测度工业碳排放的脱钩效应.研究结果表明：产出规模效应、技术进步效应、能源消费规模效应和人均碳排放效应是导致工业碳排放增加的主要因素,而产出碳强度效应与技术进步碳强度效应是减少工业碳排放的关键因素;工业碳排放的脱钩效应呈"未脱钩~弱脱钩~强脱钩"的阶段性特点;产出碳强度效应与技术进步碳强度效应是工业碳排放实现强脱钩的决定性因素,同时更需要调整能源结构、降低能源强度与碳排放强度来实现工业碳排放强脱钩.     

Benefits, efforts and risks of participants in landscape co-management: an analytical framework and results from two case studies in Austria

Participatory processes in general and also in relation to managing landscape issues are gathering importance mostly due to arguments surrounding legitimacy and effectiveness in decision-making. The main aim of this research, based on a transaction costs perspective, is to present an integrated analytical framework in order to determine individual efforts (time, money), benefits and risks of participants in landscape co-management processes. Furthermore a reflection on the analytical approach developed and arising lessons to be learned for landscape co-management are presented. In the analytical framework benefit-components comprise of factors such as 'contributing to landscape maintenance/development and nature protection', 'representing one's interest group', 'co-deciding on relevant topics', 'providing and broadening one's knowledge' and 'building networks'. The risks of participation are related to a lack of information and agreements, missing support and actual decision-making power. The analytical framework is applied to two case studies in Austria: an EU LIFE-Nature project and a Cultural Landscape Project of the Provincial Government of Lower Austria. Analysis of the effort-benefit-relations provides an indication for a more effective design of co-management. Although the processes are rated as quite adequate, there is a low willingness of participants to commit additional time to co-management processes. In contrast to the Cultural Landscape Project, in the LIFE-Nature project, professionally involved persons participate next to partly and full volunteers. These uneven conditions of participation and an unfair distribution of transaction costs, jeopardize the promising chances co-management bears for landscape governance.     

Effects of risks of sperm competition on the numbers of eupyrene and apyrene sperm ejaculated by the moth Plodia interpunctella (Lepidoptera: Pyralidae)

This study examines the effects of different risks of sperm competition upon ejaculate characteristics in the moth Plodia interpunctella. In this short-lived species, females will remate and thus generate sperm competition, while males have a limited sperm supply. We therefore predict males to have evolved prudence in ejaculate allocation and investigate the effects of (1) rival male presence, (2) female mating history and (3) female age, upon the ejaculation of eupyrene (fertilizing) and apyrene (non-fertile) sperm numbers. We found no effect of the presence of rival males upon ejaculate characteristics, and conclude, due to the mating system of P. interpunctella, that rival males do not represent a proximate risk of sperm competition. We controlled female mating history by allowing females to receive different and predictable numbers of sperm which they then store for at least 7 days. In subsequent matings (7 days later) we found that new males ejaculated significantly more eupyrene sperm to females that had previously received larger numbers of sperm. We conclude that males increase numbers of eupyrene sperm to maintain success in sperm competition with rival sperm already in storage in the female. We found no effect of female mating history upon the ejaculation of apyrene sperm. Female age, however, had a significant negative effect upon both sperm types. We discuss these results in relation to sperm competition theory and apyrene sperm function.     

Sexual harassment and female gregariousness in the South American sea lion, Otaria flavescens

Most colonial pinnipeds form extreme clusters of breeding females that cannot be entirely explained by the distribution of sites for reproduction. Avoidance of male harassment has been postulated as an important determinant of reproductive aggregation in this group of mammals. Female gregariousness can reduce harassment by resident males by two mechanisms; directly by the 'dilution effect' or indirectly because resident males that defend large female groups are less harassing. In order to investigate the relationship between male harassment and female gregariousness in relation to the size of breeding groups, we analysed the behaviour of dominant males and their females in a breeding colony of Otaria flavescens. Females in large breeding groups received less harassment by resident males due to dilution effects and because males that defended a large group interacted less frequently with females than males with small groups.     

Sex,age, spleen size,and kidney fat of red deer relative to infection intensities of the lungworm <Emphasis Type="Italic">Elaphostrongylus cervi</Emphasis>

We analyzed the relationships among spleen size, body condition (measured as kidney fat), and larval counts of the nematode Elaphostrongylus cervi in red deer (Cervus elaphus). The aim was to investigate the interaction between host body condition and intensity of infection with parasites. As red deer are highly polygynous, we also tested whether these relationships varied with sex and age of the hosts. Kidney fat and spleen size were positively correlated in subadults (2–3 years old) and adults (>3 years old), but not in calves (<1 year old) or yearlings (1–2 years old). Spleen size was negatively associated with nematode load in subadult females and in adult males. These two age classes are potentially the most nutritionally stressed, as subadult hinds are still growing and often engaging in rearing their first calf, and adult stags were sampled just after the rut, which is recognized as a substantial energy drain in this age–sex class, as they compete to hold females during the mating season. Body condition related negatively to parasite count only in adult males. In the context of red deer life history, these findings suggest that spleen size is dependent on body condition and that it could be affected by variation in resource partitioning among immune defense, growth, and reproductive effort in red deer. For the first time in a wild mammal, the spleen mass is shown to be positively related to body condition and negatively related to parasite infection. We conclude that elucidating whether spleen mass reflects immune defense investment or a measure of general body condition should contribute to understanding topical issues in mammal ecology.     

Identifying fishing trip behaviour and estimating fishing effort from VMS data using Bayesian Hidden Markov Models

Recent advances in technologies have lead to a vast influx of data on movements, based on discrete recorded position of animals or fishing boats, opening new horizons for future analyses. However, most of the potential interest of tracking data depends on the ability to develop suitable modelling strategies to analyze trajectories from discrete recorded positions. A serious modelling challenge is to infer the evolution of the true position and the associated spatio-temporal distribution of behavioural states using discrete, error-prone and incomplete observations. In this paper, a Bayesian Hierarchical Model (HBM) using Hidden Markov Process (HMP) is proposed as a template for analyzing fishing boats trajectories based on data available from satellite-based vessel monitoring systems (VMS). The analysis seeks to enhance the definition of the fishing pressure exerted on fish stocks, by discriminating between the different behavioural states of a fishing trip, and also by quantifying the relative importance of each of these states during a fishing trip. The HBM approach is tested to analyse the behaviour of pelagic trawlers in the Bay of Biscay. A hidden Markov chain with a regular discrete time step is used to model transitions between successive behavioural states (e.g., fishing, steaming, stopping (at Port or at sea)) of each vessel. The parameters of the movement process (speed and turning angles) are defined conditionally upon the behavioural states. Bayesian methods are used to integrate the available data (typically VMS position recorded at discrete time) and to draw inferences on any unknown parameters of the model. The model is first tested on simulated data with different parameters structures. Results provide insights on the potential of HBM with HMP to analyze VMS data. They show that if VMS positions are recorded synchronously with the instants at which the process switch from one behavioural state to another, the estimation method provides unbiased and precise inferences on behavioural states and on associated movement parameters. However, if the observations are not gathered with a sufficiently high frequency, the performance of the estimation method could be drastically impacted when the discrete observations are not synchronous with the switching instants. The model is then applied to real pathways to estimate variables of interest such as the number of operations per trip, time and distance spent fishing or travelling.     

Ranked set sample design for environmental investigations

Ranked set sampling can provide an efficient basis for estimating parameters of environmental variables, particularly when sampling costs are intrinsically high. Various ranked set estimators are considered for the population mean and contrasted in terms of their efficiencies and useful- ness, with special concern for sample design considerations. Specifically, we consider the effects of the form of the underlying random variable, optimisation of efficiency and how to allocate sampling effort for best effect (e.g. one large sample or several smaller ones of the same total size). The various prospects are explored for two important positively skew random variables (lognormal and extreme value) and explicit results are given for these cases. Whilst it turns out that the best approach is to use the largest possible single sample and the optimal ranked set best linear estimator (ranked set BLUE), we find some interesting qualitatively different conclusions for the two skew distributions     

Sex-biased dispersal in a long-lived polygynous reptile (Crocodylus johnstoni )

We compared natal dispersals of freshwater crocodiles (Crocodylus johnstoni) against the prediction of male dispersal bias for a polygynous mating system. The crocodiles inhabited a linear series of pools and we calculated the net distances from natal pools to recapture locations some 12–18 years later, at maturity. Philopatry was assessed in terms of adult social distances. A female social distance was 0.46 pools and a male social distance was 1.0 pool. By these criteria, both sexes showed low levels of philopatry (7–12%). However, individuals of both sexes dispersed from the natal site long before they were sexually mature. Divergence in dispersal patterns by sex occurred after the maturity threshold, as males dispersed two to three times farther than females. Intrasexual competition by males is resolved by a size-based hierarchy. The displacement of small males from local mating access is a probable cause of the longer dispersals undertaken by males. Competition, rather than inbreeding avoidance, is driving dispersal in this population of freshwater crocodiles. Received: 8 May 1998 / Accepted after revision: 26 June 1998