龙胜县里骆林区林木害虫及其生态环境的初步调查

根据调查,里骆林区森林昆虫种类相当丰富,存在不少灾害性的害虫种类,如松毛虫、松毒蛾、油茶毒蛾、松天牛、皱鞘双条杉天牛等;其中食叶害虫没有成灾,蛀干害虫特别是天牛类为害相当严重;另外也发现一些罕见的严重为害的种类,如檫木网蝽、樟树盾蝽等。本文还初步探讨了该林区害虫的发生与生态环境的关系,为林区害虫治理工作提出初步建议。     

基于机器视觉的松林天牛远程智能监测系统

松墨天牛和褐梗天牛是松树上两种重要蛀干害虫，及时获取松林天牛的数量变化趋势是松林害虫精准防治的重要前提。为此，该研究构建一款基于机器视觉的松林天牛远程智能监测系统。系统主要由诱捕器模块、天牛检测模块和系统Web端三部分组成。诱捕器模块通常放置于松林重点区域来诱捕天牛害虫，并通过摄像头定时采集天牛图像；天牛检测模型部署于边缘端，以深度学习YOLOv5s模型为基础搭建轻量化检测模型，实现边缘端的天牛实时检测统计；检测结果经无线传输在系统Web端进行呈现，实现天牛数据可追溯。试验结果表明，智能监测系统对天牛监测效果良好，模型的准确率为94.4%，召回率为93.6%,IoU阈值为0.5下的平均精度均值(m AP0.5)为96.2%，单张推理耗时为1.40 s，模型大小为9.3 MB；用户可通过系统Web端查看天牛数量变化趋势。该系统可实现诱捕器场景下的天牛远程智能监测，对提高森林害虫防控智能化水平具有重要意义。     

花绒寄甲对浙江省沿海防护林天牛的防治效果探究

沿海防护林在浙江省森林生态系统中具有非常重要作用,还是沿海地区防灾减灾体系的重要组成部分。近年来,天牛类蛀干害虫对海防林的为害及影响越来越大。基于此,以不同的比例释放寄生性天敌花绒寄甲,在浙江省宁波慈溪、余姚和台州临海的沿海防护林进行防治试验。结果表明,花绒寄甲对慈溪、余姚和临海等地沿海防护林的天牛均能起到良好的防治效果。     

麦田害虫与天敌群落动态变化研究

2008年3月15日至5月29日系统调查了冬小麦田害虫与天敌的种群数量动态,并利用相对丰富度、优势度指数、优势集中性指数、多样性指数和均匀度分析了害虫与天敌群落动态变化及时间生态位。结果表明:麦田昆虫群落组成较为丰富,由11目39科59种昆虫组成;优势种为麦长管蚜(Macrosiphum avenae)、麦圆叶爪螨(Penthaleus major)、龟纹瓢虫(Propylea japonica)和麦蚜茧蜂(Ephedrus plagiator)。群落的总个体数和丰富度随调查时间而变化;多样性指数与均匀度指数在小麦生长前期较低,中期和后期较高,两者变化规律基本一致,而优势集中性指数变化趋势与其相反。在害虫种群中以棉铃虫(Helicoverpa armigera)种内竞争最为激烈,条斑叶蝉(Psammotettix striatus)的竞争最缓和;棉铃虫与麦长管蚜种间竞争最强,其次为麦圆叶爪螨与小麦叶蜂(Dolerus tritici)。在天敌种群中以七星瓢虫(Coccinella septempunctata)种内竞争最为激烈,麦蚜茧蜂的种内竞争最为缓和;龟纹瓢虫分别与七星瓢虫和异色瓢虫(Leis axyridis)在时间维度上的竞争较为激烈,而麦蚜茧蜂分别与龟纹瓢虫、七星瓢虫和异色瓢虫的竞争比较缓和。从害虫种群与天敌种群之间的重叠值看,异色瓢虫和七星瓢虫对棉铃虫的控制作用较强,而麦蚜茧蜂和龟纹瓢虫则对麦田主要害虫麦长管蚜、条斑叶蝉和小麦潜叶蝇(Phytomyza nigra)等的跟随和控制作用均较强。     

南安市水头镇松墨天牛虫口数量调查分析

松墨天牛是松树主要的蛀干害虫,广泛分布中国东部沿海地区。本次使用高效引诱剂APF-1配合ZM80B型诱捕器对福建省南安市水头镇进行松墨天牛诱捕,以统计分析水头镇的松墨天牛虫口数量,结果显示3个月内在水头镇共诱捕松墨天牛成虫1 080头,其中诱捕虫口数量最多的为呈美村,诱捕松墨天牛316头,虫口数量最少的为朴山村,仅诱捕到松墨天牛11头,各村落的平均诱捕数也存在较大差异,邦呤村与曾岭村平均以26.5头和25.4头在诱捕松墨天牛的数量上最佳,而朴山村平均每套诱捕装置只诱捕到天牛11只。各月捕捉到的松墨天牛数也有所不同,其中10月捕捉到的虫口数量最多,9月与11月基本相同,可以说明虫口在10月左右生命活动较为活跃,对引诱剂兴趣较大。     

现代信息技术在害虫种群密度监测中的应用

害虫种群密度监测是害虫预测准确度关键，对农田生态系统中害虫综合管理有重要指导意义。该文从传统的害虫监测技术入手，分析了近年现代信息技术在害虫自动化监测中应用的进展，分析了计算机视觉、声音信号、传感器、雷达和遥感等信息技术在害虫密度估算中的优势和存在的问题，指出了计算机视觉技术和传感器技术是具有潜力的监测技术，阐述了现代信息技术在害虫自动化监测的主要方向和实现途径，对未来农田生态系统中害虫预测和综合管理具有重要意义。     

土壤施肥与植食性害虫发生为害的关系

土壤施肥可以影响植物的生长和营养状况,从而影响植食性昆虫的生长发育、繁殖和为害等。在影响植物抗性和害虫为害的营养因子中,氮是一个关键的因素,氮肥对害虫发生的影响取决于害虫种类、植物种类和土壤肥力,是植物营养质量对害虫直接影响的结果,也是植物形态学、组织发育等因素的间接作用结果。很多研究表明土壤或植物中氮水平与害虫密度存在强烈正相关关系,但是也有不同情况出现。另外其他营养元素如磷和钾,也会引起害虫种群动态变化。有机管理措施可能有利于减轻害虫发生,但是机理还存在争议。     

太行山低山丘陵区鳞翅目趋光性昆虫种群动态初报

采用黑光灯引诱逐日调查的方法,研究了太行山低山丘陵区鳞翅目趋光性昆虫种群数量动态变化规律。结果表明,实验区鳞翅目趋光性昆虫共有206种,分属16科。玉米螟、木撩尺蛾、棉铃实夜蛾和豆荚野螟为优势害虫种群。昆虫种群动态可分为零星出现、连续少量出现和连续大量出现3种类型,揭示了鳞翅目昆虫种群数量变化规律,为制定防治害虫对策提供理论依据。     

农业景观害虫控制生境管理及植物配置方法

集约化农业生产过程中,化学农药所带来的大量环境问题日益引起关注。为减少农药的投入及其所产生的环境负效应,生物防治害虫的方法在国内外得到了更多的关注与发展。生境管理是一种有利于天敌群落发展,而不利于害虫种群增长的保护性生物防治方法,其实质是通过为自然天敌提供诸如花蜜、替代猎物或寄主、躲避不利干扰的庇护所等资源,将农业景观中天敌的害虫控制服务和功能最大化,或者通过构建不适宜害虫取食和繁殖的环境条件起到抑制或阻碍害虫发展的作用。本文在参阅国内外文献的基础上,阐述了生境管理控制害虫的机理,并总结国外生物防治的实践经验以及近些年国内外的相关研究,概括提出田间尺度上害虫生物防治的非作物生境及作物生境的建设和植物配置方法,为通过生境管理提升农业景观中害虫生物防治生态系统服务提供参考。     

太行山低山丘陵区鳞翅目趋光性昆虫种群动态初报

采用黑光灯引诱逐日调查的方法,研究了太行山低山区陵区鳞翅日趋光性昆虫种群数量动态变化规律。结果表明,实验区鳞翅目趋光性昆虫共有２０６种,分属１６科。玉米螟木尺蛾,棉铃实夜蛾和豆荚野螟为优势害虫种群。昆虫种群动态可分为零星出现,连续少量出现和连续大量出现３种类型,揭示了鳞翅目种群数量变化规律,为制定防治害虫对策提供理论依据。     

Alfalfa saponins and microbial transformations of nitrogen in peat

Alfalfa saponins, their sugar fraction or glucose, but not their sapogenin fraction, favored nitrogen immobilization and denitrification and inhibited proteolysis and ammonification in both peatinoculated and Pseudomonas sp.-inoculated media. Alfalfa root saponins and sapogenins significantly reduced the fungal peat population, but did not affect the bacterial population. The inhibition of N mineralization in peat by saponins and by their sapogenin fraction during dry and wet cycles was mostly due to their fungistatic activity. The inhibitory effect of the sugar fraction of alfalfa roots on mineral-N accumulation in peat is mainly under moist conditions.     

Dynamics of public attitudes toward bears and the role of bear hunting in Croatia

Successful carnivore conservation depends on public attitudes and acceptance levels of carnivores, and these are likely to change as circumstances change. Attitude studies repeated in time that can demonstrate such change are rare. Our study surveyed Croatian rural inhabitants in 2002 and in 2008 and analyzed their responses to detect a change in attitudes toward brown bears (Ursus arctos) over time. Important developments occurring in Croatia at the time of our research included a more centralized and more clearly defined bear management strategy, and an increase in the bear population. We constructed models to explain respondent’s value orientations, their level of perceived threat and their acceptance capacity for bears. Findings show that while value orientations and the overall level of perceived threat did not change over time, bear acceptance capacity was reduced. This suggests that the increase in the bear population and perhaps the more centralized bear management reduced respondents’ willingness to accept a larger bear population. We conclude that continuous public involvement in bear management is essential in order to maintain a feeling of control over the bear among the local population. Furthermore we argue that hunting is an important form of public involvement in the region, serving to reinforce existence and bequest values of the bear and increase its public acceptance.     

Microbial cenoses of alas soils on the Lena-Amga interfluve in Central Yakutia

The specific features of the microbial population in the soils of alases (thermokarst depressions) of Central Yakutia were revealed: a high number of microorganisms of all the groups (1.1 × 10³–3.9 × 10⁸ cell/g), which is compatible with the microbial density in the steppe soils of Transbaikalia; a particular distribution of the microorganisms along their profiles without decreasing of their number with the depth; and insignificant fluctuations of their population density in some soil horizons. The enrichment of these soils with microorganisms depends on the hydrothermal conditions. The microbial number gradually increases from the elevated peripheral parts of the alases to their centers and drastically decreases towards the lower lakeside areas of the alases. At the same time, the composition of the microorganisms changes, and nitrogen-fixing bacteria appear.     

Hatch size, somatic growth rate and size-dependent survival in the endangered ploughshare tortoise

Successful conservation requires a good understanding of both the direct and indirect causes of any decline in population size. Harvests of wild populations often target the largest, oldest individuals that have the greatest economic value. If these individuals contribute disproportionately more to recruitment than conspecifics, the harvest will cause a greater reduction in population viability than initially anticipated. The ploughshare tortoise, endemic to Madagascar, has been reduced to <600 individuals due to exploitation and habitat loss. A trial release of captive-bred juveniles has been carried out but the relative suitability of individuals for release, in terms of body size, was not considered. Using data from a long-term mark-recapture study of an unharvested wild population of ploughshare tortoises, we found that larger juveniles were significantly more likely to survive their first year of life than smaller tortoises. Juveniles that survived beyond their first year of life generally grew at the same rate, but had a significantly larger hatch size (mean = 41.7 mm), compared with juveniles that did not survive (mean = 39.3 mm). The conservation implications of these results are that release of captive-bred ploughshare tortoises is likely to be more successful if larger individuals are released. Previous studies have reported larger female ploughshare tortoises laying larger eggs which hatch larger juveniles. This study shows individuals with a larger hatch size retain their size advantage over smaller conspecifics and are more likely to survive their first year of life. This suggests a harvest that targets the largest females in the ploughshare tortoise population could be highly detrimental to population viability.     

Evidence for food limitation in the declining hen harrier population on the Orkney Islands, Scotland

The hen harrier (Circus cyaneus) population on the Scottish Orkney Islands has declined dramatically since the end of the 1970s. We postulate that the cause of this decline was due to a reduction in the amount of available prey and predict that if this was the case the population would currently be limited by food. The evidence for this hypothesis is explored by examining the rates at which males deliver prey to their females in relation to breeding performance both among individuals within the declining population and also between this declining population and another, non-declining population in southern Scotland. Breeding performance within the Orkney population was related to male provisioning rates: males that provided more food to their females were more likely to initiate a breeding attempt and there was a tendency for males with the highest provisioning rates to breed with more females. Comparisons between the two populations revealed that harriers on Orkney had a lower breeding performance and also a lower rate of food provision. Changes in agriculture, in particular decreases in rough grazing and increases in sheep densities are thought to be the most likely cause for a reduction in food supply. Conservation measures should be aimed toward increasing the areas of rough grass habitat.     

Astigmatid mite growth and fungi preference (Acari: Acaridida): Comparisons in laboratory experiments

The relationship between palatability and suitability of fungi for sustaining mite population growth was tested in the laboratory. The effect of mite fungal preference on spore dispersion was also studied. Eight species of microscopic fungi, Alternaria alternata, Aspergillus niger, Aspergillus versicolor, Cladosporium cladosporioides, Eurotium amstelodami var. amstelodami, E. amstelodami var. montevidensis, Mycocladus corymbifer, and Penicillium aurantiogriseum differed in their attractiveness as food and in their suitability to sustain population growth of three astigmatid mites, Acarus siro, Lepidoglyphus destructor and Tyrophagus putrescentiae. The preference for a particular species of fungus and its suitability for sustaining population growth were not correlated. Observed differences among mite species in their population growth were more likely associated with their ability to digest fungi. Fungi were divided into four groups based on their palatability and suitability to sustain population growth: (i) preferred food and suitable for mite growth (e.g. A. alternata, C. cladosporioides); (ii) preferred, but unsuitable (e.g. E. amstelodami var. amstelodami); (iii) avoided, but suitable (e.g. A. versicolor, M. corymbifer and E. amstelodami var. montevidensis); and (iv) avoided and unsuitable (e.g. A. niger). With respect to fungal spore dispersion, mites had the least effect on “avoided and unsuitable” fungal species while preferred fungi were most influenced by mite grazing.     

Modelling the effects of persecution on the population dynamics of golden eagles in Scotland

We used observations of the age structure and breeding productivity of the Scottish population of golden eagles Aquila chrysaetos together with the classic theory of population dynamics to derive current `unmanipulated' estimates of life history parameters. We then used regional differences in age structure associated with differences in persecution intensity to derive estimates of prospective `persecution-free' life history parameters. The different parameter combinations were entered into a population model to simulate their effects on the number of occupied territories over time. Most simulations suggested that with unmanipulated demographic parameters the population should decline. The disparity between these predictions and the observed apparent stability in occupied territories was ascribed to the buffering effect of a lowering in age of breeding in areas where persecution is most intense and that more favourable parameter estimates within the estimated limits may be more realistic. The results indicated, nevertheless, that currently the population is vulnerable to decline as also suggested by the apparent lack of adults to occupy vacant territories. In the absence of the estimated 3-5% annual adult mortality through persecution, modelling suggested the population would increase. Removing estimated effects of persecution on reproductive rate and preadult survival were on their own insufficient to reverse the declines predicted from unmanipulated parameters, although the effect of persecution on preadult survival may be more severe than we estimated. In the absence of persecution we conclude that the population could expand to fill currently vacant but apparently suitable habitat and have a more secure long-term status.     

High levels of hatching failure in an insular population of the South Island robin: a consequence of food limitation?

Endangered birds in insular environments like New Zealand are often translocated to predator-free offshore islands for conservation purposes. Some translocated populations however exhibit reduced fecundity, and it has been suggested that either inbreeding (due to small number of founders) or resource shortages (due to high population density) may limit reproductive success. For example, the South Island robin (Petroica a. australis) population on Motuara Island (59 ha) was founded by only five birds but has increased to ∼600 individuals, or a density >10 times that of the mainland. Despite this apparent success, the rate of hatching failure in this population is three times higher than in mainland populations, with more than a third of eggs failing to hatch. To test if elevated hatching failure is the result of food limitation, we carried out a food supplementation experiment by providing females with mealworms equivalent to ∼50% of their daily energy requirements. Food supplementation had no effect on hatching success, clutch size, incubation attentiveness or nest size. Egg volume increased with food supplementation in one of the two years of this study, but both egg volume and incubation attentiveness were unrelated to rate of hatching failure. As previous genetic analyses confirmed that the bottlenecked population of robins on Motuara Island have significantly less genetic variation than their source population, we conclude that inbreeding depression, and not food limitation, is the most likely explanation for their high rate of hatching failure. We suggest that the experimental translocation of genetically dissimilar individuals be considered as a possible remedy for low productivity in island populations that were initiated with few founders.     

Impacts of chronic marine oil pollution and the murre hunt in Newfoundland on thick-billed murre Uria lomvia populations in the eastern Canadian Arctic

We developed a deterministic and stochastic age-based matrix projection population model to assess and quantify the impact of mortality caused by chronic oil pollution and legal hunting on thick-billed murre Uria lomvia populations breeding and wintering in eastern Canada. We calculate the potential population growth rate in the absence of anthropogenic mortality sources using a modeling technique that translates absolute number of birds killed from anthropogenic mortality to potential survival rates in the absence of these anthropogenic impacts. The intrinsic growth rate of the deterministic matrix based on vital rates from Coats Island (λ_d=1.0102), as well as the stochastic growth rate (λ_s=1.0098, 95% C.I. 0.9969-1.0226), matched observed population trends. Hunting mortality reduced population growth rate by 0.020 (0.012-0.039), oiling mortality reduced population growth rate by 0.025 (0.012-0.039). Combined these sources reduced the population growth rate by 0.047 (0.033-0.610). Although thick-billed murre populations are stable or slowly growing in eastern Canada, anthropogenic sources of mortality are reducing the ability of the population to grow, and increase vulnerability in these populations to changes in their environment and other pulse perturbations. Our modeling technique could be used to assess specific anthropogenic impacts on populations where a vital rates and numbers killed are known, but no long-term trend information is available.     

Genetic insights into population recovery following experimental perturbation in a fragmented landscape

We investigated the mechanism of population recovery in the Australian bush rat, Rattus fuscipes, following experimental perturbation in a fragmented landscape. Our study involved genetic monitoring over 24 months following the removal of animals from seven sites by intense trapping. A total of 171 bush rats was removed and statistical analysis confirmed a significant knockdown. At one site, local extinction followed the perturbation, while population sizes at 24 months varied from 37% to 90% of the original population size at the remaining sites. The outcomes of genetic analysis at 11 microsatellite loci and mtDNA indicated that population recovery was achieved predominantly by residual animals: recovery populations were genetically more similar to their respective pre-treatment population than near neighbours; assignment tests detected few immigrants; there was no influx of new immigrant alleles and haplotypes. This finding is consistent with emerging evidence for restricted gene flow in bush rats. The local extinction observed at one site indicate that, under severe perturbation restricted dispersal limits opportunities for, and the rate of, population recovery. Thus, while the bush rat appears resilient to substantial population size perturbation, once a critical minimum population size threshold has been reached, this species may be susceptible to local extinction. We concluded that some widespread species currently predicted to be extinction-resilient may, in fact, be at risk if localized extinctions occur and dispersal limitations prevent recolonisation.