异迟眼蕈蚊在不同植物上的生长发育及种群参数

【目的】异迟眼蕈蚊Bradysia difformis Frey的幼虫取食为害作物的地下部分,影响作物的品质,为了明确韭菜、蚕豆、生菜、白菜和甘蓝5种植物对异迟眼蕈蚊生长发育以及繁殖的影响。【方法】本试验采用室内人工饲养测定的方法,研究了5种不同植物对异迟眼蕈蚊生长发育,繁殖力和存活率的影响,并统计了其对异迟眼蕈蚊种群参数的影响。【结果】结果表明:卵到蛹的发育历期依次为甘蓝、白菜、韭菜、生菜、蚕豆;5种植物对雌雄虫寿命影响不显著,对雌虫产卵量以及蛹重均有影响,其中在韭菜上的产卵量最大,甘蓝最少,在韭菜上蛹最重,生菜上蛹最轻;异迟眼蕈蚊的存活率随着生长发育降低,总体在韭菜上的存活率高于其他寄主植物,在生菜上的存活率均最低。统计分析不同植物对异迟眼蕈蚊种群参数的影响,净增殖率和内禀增长率在韭菜上最大而在甘蓝上最小;平均世代周期在蚕豆上最短,甘蓝上最长;种群加倍时间在韭菜上最短,而在甘蓝上最长。【结论】由此可知,异迟眼蕈蚊均可以在韭菜,蚕豆,生菜,白菜和甘蓝上完成生长发育及繁殖,其对5种植物的适应性依次为:韭菜、蚕豆、白菜、甘蓝和生菜。     

Demographic responses to weather fluctuations are context dependent in a long‐lived amphibian

Weather fluctuations have been demonstrated to affect demographic traits in many species. In long‐lived organisms, their impact on adult survival might be buffered by the evolution of traits that reduce variation in interannual adult survival. For example, skipping breeding is an effective behavioral mechanism that may limit yearly variation in adult survival when harsh weather conditions occur; however, this in turn would likely lead to strong variation in recruitment. Yet, only a few studies to date have examined the impact of weather variation on survival, recruitment and breeding probability simultaneously in different populations of the same species. To fill this gap, we studied the impact of spring temperatures and spring rainfall on survival, on reproductive skipping behavior and on recruitment in five populations of a long‐lived amphibian, the yellow‐bellied toad (Bombina variegata). Based on capture–recapture data, our findings demonstrate that survival depends on interactions between age, population and weather variation. Varying weather conditions in the spring result in strong variation in the survival of immature toads, whereas they have little effect on adult toads. Breeding probability depends on both the individual's previous reproductive status and on the weather conditions during the current breeding season, leading to high interannual variation in recruitment. Crucially, we found that the impact of weather variation on demographic traits is largely context dependent and may thus differ sharply between populations. Our results suggest that studies predicting the impact of climate change on population dynamics should be taken with caution when the relationship between climate and demographic traits is established using only one population or few populations. We therefore highly recommend further research that includes surveys replicated in a substantial number of populations to account for context‐dependent variation in demographic processes.     

Relative longevity of adult Nezara viridula in field cages of cotton,peanut, and soybean

Producers in the southeastern USA face significant crop losses from the stink bugs Nezara viridula (L.), Euschistus servus (Say), and Chinavia hilaris (Say) (all Hemiptera: Pentatomidae). Cotton, peanut, and soybean are major agronomic crops and host plants of stink bugs in the region. We conducted a field plot study to measure the relative longevity of adult, unmated N. viridula males and females caged on peanut, cotton, and soybean to test three hypotheses: (1) differences in mortality are associated with differences in host plant food suitability, (2) mortality rates increase with age, and (3) males have higher mortality than females. Using survival analysis, we found that the sex of the individual did not affect survival rates on any of the three host plants. Survival was significantly higher in cotton and soybean than in peanut. Mortality rates increased with age in peanut, but not in soybean or cotton. The frequency of canopy temperatures above 35 °C was higher in peanut than in soybean. Peanut appears to be a less than ideal habitat in terms of canopy temperature and/or food quality for N. viridula adults. Both, cotton and soybean were equally suitable food resources for N. viridula adults prior to maturation of the plants.     

Scaling Humanitarianism: Humanitarian Actions in a Bosnian Town

Through an ethnographic focus on humanitarne akcije in Bosnia and Herzegovina – a local form of raising monetary donations to people who need medical treatments abroad – this paper explores humanitarianism and its understandings of life. Ethnographically tracking the course of a humanitarna akcija organised in one Bosnian town, this paper makes two related points. First, it ethnographically demonstrates that lives of the ‘helpers’ and ‘helped’ in humanitarne akcije were understood as immersed in the intense talk and gossip of the town and as exposed to the sociopolitical environment troubled in the same way. Comparing this understanding of life with the international humanitarianism, this paper suggests that the notion of ‘bare life’ in international humanitarian projects in emergencies may be the product of the separation of infrastructures, which enable and manage lives of the ‘savers’ and ‘saved’. Second, those who needed help through humanitarne akcije strongly criticised the lack of organised health care and social security in Bosnia and Herzegovina that pushed them to initiate humanitarne akcije. They criticised less how other people perceived them (the terms of their sociocultural recognition) and more the shrinking public health-care insurance, unavailability of medical treatments, unequal allocation of medicines, tissues and organs, and so forth (the unjust redistribution of resources). Their dissatisfactions imply that humanitarianism as an industry of aid can be criticised for failing to intervene in the global regimes of unequal redistribution of resources in a transformative way.     

A review of survival estimates for raptors and owls

This paper reviews the literature on survival estimates for different species of raptors and owls, examines the methods used to obtain the estimates, and draws out some general patterns arising. Estimating survival usually involves the marking of birds so that they can be recognized as individuals on subsequent encounters. Annual survival can then be estimated from: (1) birds ringed at known age (usually as nestlings) and subsequently reported by members of the public (usually as found dead), the ratio of recoveries at different ages being used to calculate annual survival; (2) marked breeding adults, trapped or re‐sighted in subsequent years in particular study areas, with the proportion re‐trapped (or re‐sighted) in each year being taken as the minimum annual survival; (3) live encounter (trapped or re‐sighted) of birds marked either as nestlings or breeding adults analysed using the capture–mark–recapture (or re‐sighting) methods to estimate annual survival; (4) a combination of reports of known‐age dead birds and re‐trapping/re‐sighting of live birds; (5) use of radio‐ or satellite‐tracking to follow the fates of individuals; and (6) the integration of these methods with other information, such as change in numbers between years, to derive estimates of survival and other demographic parameters. Studies confined to particular areas usually give estimates of ‘apparent annual survival’, because they take no account of birds that leave the area. However, radio‐ or satellite‐tracking makes it possible to estimate true survival, including survival of prebreeders that have low natal‐site fidelity (this usually requires satellite telemetry). As in other birds, the preferred method for estimating survival has changed over time, as new and more robust methods of estimation have been developed. Methods 1 and 2 were the first to be developed, but without statistical underpinning, while methods 3–6 were developed later on the basis of formal statistical models. This difference has to be borne in mind in comparing older with newer estimates for particular species. Published survival estimates were found for three species of Cathartidae, one of Pandionidae, 29 of Accipitridae, 12 of Falconidae, one of Tytonidae and nine of Strigidae, almost all from temperate Northern Hemisphere species. In most of these species more than one estimate was available, and in some separate estimates for different age or sex groups. The main patterns to emerge included: (1) a significant tendency for annual adult survival to increase with body weight, smaller species having annual survival rates mainly of 60–70%, medium‐sized species having rates mainly in the range 70–90% and the largest having rates of > 90%, in the absence of obvious human‐caused losses; (2) a lower survival in the first or prebreeding years of life than in subsequent years; (3) a lack of obvious or consistent differences in survival between the sexes, where these could be distinguished; and (4) in the few species for which enough data were available, a decline in annual survival rates in the later years of life.     

Robust estimation of survival and contribution of captive‐bred Mallards Anas platyrhynchos to a wild population in a large‐scale release programme

The survival of captive‐bred individuals from release into the wild to their first breeding season is crucial to assess the success of reintroduction or translocation programmes, and to assess their potential impact of wild populations. However, assessing the survival of captive‐bred individuals following their release is often complicated by immediate dispersal once in the wild. Here, we apply Lindberg's robust design model, a method that incorporates emigration from the study site, to obtain true estimates of survival of captive‐bred Mallards Anas platyrhynchos, a common duck species released on a large scale in Europe since the 1970s. Overall survival rate from release in July until the onset of the next breeding season in April was low (0.18 ± 0.07 se) and equivalent to half the first‐year survival of local wild Mallards. Higher overall detectability and temporary emigration during the hunting period revealed movements in response to hunting pressure. Such low survival of released Mallards during their first year may help prevent large‐scale genetic mixing with the wild population. Nevertheless, by combining our results with regional waterfowl counts, we estimated that a minimum of 34% of the Mallards in the region were of captive origin at the onset of the breeding season. Although most released birds quickly die, restocking for hunting may be of sufficient magnitude to affect the wild population through genetic homogenization or loss of local adaptation. Robust design protocols allow for the estimation of true survival estimates by controlling for permanent and temporary emigration and may require only a moderate increase in fieldwork effort.