21世纪可替代脊椎动物进行生态毒性测试的方法：过去二十年的发展和现状综述

替代脊椎动物进行化学物质和污染物危害评估的方法已成为越来越重要的需求。现在首先要考虑的是当启动一个脊椎动物生态毒性测试,必须确保不必要的脊椎动物生物的使用尽可能最小化。对于一些监管目的,脊椎动物的使用对环境风险评估(ERA)已经被禁止,而在其他情况下生物测试的数量已经大大减少了,或者测试程序严格精简了。然而,想要获得能够完全替代脊椎动物提供环境危害数据的方法仍有很长的路要走。动物替代品的发展不仅仅是基于道德的考虑,也可以降低执行脊椎动物生态毒性测试的成本以及在某些情况下能够提供更好的信息旨在改进环境风险评估。本文集中综述了在过去的几十年里生态毒性评估替代方法所发生的重大的进展。
精选自Adam Lillicrap, Scott Belanger, Natalie Burden, David Du Pasquier, Michelle R. Embry, Marlies Halder, Mark A. Lampi, Lucy Lee, Teresa Norberg-King, Barnett A. Rattner, Kristin Schirmer, Paul Thomas. Alternative approaches to vertebrate ecotoxicity tests in the 21st century: a review of developments over the last two decades and current status. Environmental Toxicology and Chemistry: Volume 35, Issue 11, pages 2637–2646, November 2016. DOI: 10.1002/etc.3603
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3603/full
     

基于非本地物种毒性数据推导出的水质基准可为本地物种提供适当保护吗？

基于非本地物种的毒性数据推导出的水质基准一直存在争议,质疑者提出应有针对不同生物区系的水质基准。而这个问题在中国尤为突出。本文作者搜集了38种污染物对本地物种和非本地物种的毒性数据,比较了这些生物的HC₅和物种敏感度分布,结果显示,基于非本地物种推导的水质基准有74%的确定性可以有效保护中国的水生态系统。如果采用评价因子(AF=5)来校正基准,那么可以获得90%的确定性。
精选自Xiaowei Jin, Zijian Wang, Yeyao Wang, Yibing Lv, Kaifeng Rao, Wei Jin, John P. Giesy and Kenneth M. Y. Leung. Do water quality criteria based on nonnative species provide appropriate protection for native species? Environmental Toxicology and Chemistry: Volume 34, Issue 8, pages 1744–1750, August 2015. DOI: 10.1002/etc.2985
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.2985/full     

以REACH为数据源进行生命周期影响评估

由于潜在生态毒理数据的限制,生态周期影响评估中的毒性模型仅仅描述了市场上的一小部分物质。改进现有的LCIA数据情况可以通过发现新的数据来源,比如欧盟化学品注册、评估、授权和限制(REACH)数据库。本研究通过对比记录在REACH数据库和UNEP/SETAC的科学统一模型USEtox中相同化学物质的生态毒理数据来探究REACH是否具有作为数据来源的潜力。数据根据数据点的个数,报道可靠性和测试时间评估,并将每种化学物质的50%涵盖物种的危险浓度与USEtox中的数据做对比。结果强调了REACH和USEtox之间不同的数据可用性。REACH和USEtox的生态毒理学数据对比表明REACH是一个LCIA毒性鉴别的潜在生态毒理学数据来源,也显示出REACH标准的数据存在着一致性的问题,以及REACH中监管风险评估的假设可能与LCIA所需数据有出入。因此,在考虑REACH标准下的数据在LCIA的运用之前,数据质量,预处理和可运用性需要进一步的研究。探究其他可用的数据来源,发表的研究与报告也需要更深入的调查。
精选自Nienke Müller, Dick de Zwart, Michael Hauschild, Ga?l Kijko, Peter Fantke. Exploring REACH as potential data source for characterizing ecotoxicity in life cycle assessment. Environmental Toxicology and Chemistry: Volume 36, Issue 2, pages 492–500, July 2017. DOI: 10.1002/etc.3542
详情请见http://onlinelibrary.wiley.com/wol1/doi/10.1002/etc.3542/full
     

目前针对水环境化学品风险评估的方法是正确的么？

我们想要保护水生生态环境,通过测试数以千计的化学物质和成百上千的水生物种之间交互作用,得到成千上万的结果,但仍然不可能考虑到所有物质的混合情况。污染物对野生鱼类的内分泌干扰作用的课题推动了人们对如药物之类的微污染物的研究。尽管我们担心鱼类会因污染而繁殖能力下降,但并没有足够的证据表明鱼类种群处于危险之中。事实上,许多鱼类生物学家认为,在过去的30 - 40年里,鲤科的数量已经在逐步恢复中。目前的风险评估的关键在于其核心假设,也就是实验室观测或者模型预测的结果简单地适用于群体水平,显而易见这个假设是值得质疑的。 我们明白了疏于监测野生动物种群的变化成为了我们的环境保护战略的关键弱点。如果我们不知道水生野生动物物种是在减少或增加,那么我们研究的其他生态毒理行为又有多少价值呢？
精选自Andrew C. Johnson, John P. Sumpter. Are we going about chemicals risk assessment for the aquatic environment the wrong way?. Environmental Toxicology and Chemistry: Volume 35, Issue 7, pages 1609–1616, July 2016. DOI: 10.1002/etc.3441
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3441/full
     

基于非本地物种毒性数据推导出的水质基准可为本地物种提供适当保护吗？

基于非本地物种的毒性数据推导出的水质基准一直存在争议,质疑者提出应有针对不同生物区系的水质基准。而这个问题在中国尤为突出。本文作者搜集了38种污染物对本地物种和非本地物种的毒性数据,比较了这些生物的HC₅和物种敏感度分布,结果显示,基于非本地物种推导的水质基准有74%的确定性可以有效保护中国的水生态系统。如果采用评价因子(AF=5)来校正基准,那么可以获得90%的确定性。
精选自Xiaowei Jin, Zijian Wang, Yeyao Wang, Yibing Lv, Kaifeng Rao, Wei Jin, John P. Giesy and Kenneth M. Y. Leung. Do water quality criteria based on nonnative species provide appropriate protection for native species? Environmental Toxicology and Chemistry: Volume 34, Issue 8, pages 1744–1750, August 2015. DOI: 10.1002/etc.2985
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.2985/full     

基于非本地物种毒性数据推导出的水质基准可为本地物种提供适当保护吗？

基于非本地物种的毒性数据推导出的水质基准一直存在争议,质疑者提出应有针对不同生物区系的水质基准。而这个问题在中国尤为突出。本文作者搜集了38种污染物对本地物种和非本地物种的毒性数据,比较了这些生物的HC₅和物种敏感度分布,结果显示,基于非本地物种推导的水质基准有74%的确定性可以有效保护中国的水生态系统。如果采用评价因子(AF=5)来校正基准,那么可以获得90%的确定性。
精选自Xiaowei Jin, Zijian Wang, Yeyao Wang, Yibing Lv, Kaifeng Rao, Wei Jin, John P. Giesy and Kenneth M. Y. Leung. Do water quality criteria based on nonnative species provide appropriate protection for native species? Environmental Toxicology and Chemistry: Volume 34, Issue 8, pages 1744–1750, August 2015. DOI: 10.1002/etc.2985
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.2985/full     

离体模型预测鱼体肝脏清除速率：鲑鱼肝细胞和肝脏S9组分的比较

将离体肝细胞和肝脏S9组分用于获取鱼类的体外生物转化数据可以优化模拟评估对化学物质的生物富集作用。然而涉及2种方式之间的直接对比的研究却几乎没有。本研究采用冷藏保存的鲑鱼肝细胞来测定对于6种多环芳烃(PAHs)的体外本征清除速率。我们运用测定结果推测体内本征清除速率,并将其作为输入值输入一种充分搅匀的肝脏模型中来预测肝清除速率。将事先由体外灌流肝脏测定的速率作为参考来评价预测结果。在2种竞争结合的假说前提下,由鲑鱼肝细胞测出的肝清除速率与实现的测定结果基本一致(6种多环芳烃中的5种都保持在2.1倍差异以下)。尽管多环芳烃的高代谢率是可能的原因之一,这些发现与之前由肝脏S9组分得出的结果相似。对苯并芘这一种化合物而言,由S9数据得出的体内本征清除速率是由肝细胞得出结果的10倍左右,这一结果可能是由细胞吸收速率造成的传播限制引起的。尽管苯并芘的结果差异较大,由任何一种体外测试方法得出的体内本征清除速率结果通常是一致的。这些结果显示离体肝细胞和肝脏S9组分2种系统均可用于优化鱼类的生物富集评估,尤其对于体外反应速率较高的情况。不同系统在化工领域的应用性是否相同则需要进一步的研究工作。
精选自Kellie A. Fay, Patrick N. Fitzsimmons, Alex D. Hoffman, John W. Nichols. Comparison of trout hepatocytes and liver S9 fractions as in vitro models for predicting hepatic clearance in fish. Environmental Toxicology and Chemistry: Volume 36, Issue 2, pages 463–471, July 2017. DOI: 10.1002/etc.3572
详情请见http://onlinelibrary.wiley.com/wol1/doi/10.1002/etc.3572/full
     

蛋白组学分析揭示出阿特拉津对非洲爪蟾的生殖毒性源于其诱导生殖细胞凋亡并干扰紧密连接蛋白和代谢相关信号通路

阿特拉津可对雄性脊椎动物生殖系统造成不良影响,但其中分子机制尚不明了。本文作者将非洲爪蟾(Xenopus laevis)暴露于100 ppb的阿特拉津120 d,利用同位素标记相对和绝对定量(iTRAQ)技术检测了非洲爪蟾睾丸和卵巢中蛋白图谱的变化,结果显示100 ppb阿特拉津可影响爪蟾发育,延迟和阻碍雄性细精管的形成。组学分析显示,睾丸中143种以及卵巢中121种蛋白均表达异常,这些蛋白与细胞凋亡、细胞间紧密连接以及代谢途径相关。
精选自Xiuping Chen, Jiamei Wang, Haojun Zhu, Jiatong Ding and Yufa Peng. Proteomics analysis of Xenopus laevis gonad tissue following chronic exposure to atrazine. Environmental Toxicology and Chemistry: Volume 34, Issue 8, pages 1744–1750, August 2015. DOI: 10.1002/etc.2980
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.2980/full     

化学物质水体归趋与影响数据库(CAFE)，一种用于评估水环境中化学物质溢出水平的工具

化学物质水体归趋与影响 (简称CAFE)数据库是一个允许快速并无限制访问数据的集中式数据库。CAFE将现有的32 377种化学物质的归趋数据和4 498种化学物质的毒性效果数据整合至用户友好的工具中,以物种敏感度分布(SSD)的形式总结毒性数据,并提供了相关的1%和5%危害浓度(HC₁和HC₅)。为探究CAFE数据与报道的化学事故之间的联系,一项数据可用性评估显示,2000年至2014年间在美国国家应急中心呈报的55种化学物质中,32种物质的归趋和20种物质的毒性在CAFE中均有记录;2003年至2014年间由美国海洋及大气管理局呈报的205种化学物质中,86种物质的归趋和103种物质的毒性在CAFE中也均有记录。我们假设2种化学物质在环境中溢出(丙烯腈,溢出量为625桶 ;变性乙醇,溢出量为857桶),根据模型对其环境浓度进行模拟,进而说明CAFE在实际中的应用。在24 h时程的SSD中,大多数物种很可能分别在溢出后最初的35 min内和15 h内受到丙烯腈和变性酒精的影响。丙烯腈浓度在溢出后45 min已低于HC₅(17 mg?L^L-1),变性酒精浓度在溢出后60 h已低于HC₅(2 676 mg?L^L-1)。将100种化学物质以CAFE数据为基础得出的HC₅与发表的HC₅进行对比,我们发现超过一半的数值都在2倍差异以内,较少的一部分数值则超过了10倍差异。CAFE的发展提高了获取相关环境信息的能力,并可能应用于水体环境污染物溢出分析之外的更多领域。
精选自Adriana C. Bejarano, James K. Farr, Polly Jenne, Valerie Chu, Al Hielscher. The chemical aquatic fate and effects database (CAFE), a tool that supports assessments of chemical spills in aquatic environments. Environmental Toxicology and Chemistry: Volume 35, Issue 7, pages 1576–1586, July 2016. DOI: 10.1002/etc.3289
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3289/full
     

蛋白组学分析揭示出阿特拉津对非洲爪蟾的生殖毒性源于其诱导生殖细胞凋亡并干扰紧密连接蛋白和代谢相关信号通路

阿特拉津可对雄性脊椎动物生殖系统造成不良影响，但其中分子机制尚不明了。本文作者将非洲爪蟾(Xenopus laevis)暴露于100 ppb的阿特拉津120 d，利用同位素标记相对和绝对定量(iTRAQ)技术检测了非洲爪蟾睾丸和卵巢中蛋白图谱的变化，结果显示100 ppb阿特拉津可影响爪蟾发育，延迟和阻碍雄性细精管的形成。组学分析显示，睾丸中143种以及卵巢中121种蛋白均表达异常，这些蛋白与细胞凋亡、细胞间紧密连接以及代谢途径相关。
精选自Xiuping Chen, Jiamei Wang, Haojun Zhu, Jiatong Ding and Yufa Peng. Proteomics analysis of Xenopus laevis gonad tissue following chronic exposure to atrazine. Environmental Toxicology and Chemistry: Volume 34, Issue 8, pages 1744–1750, August 2015. DOI: 10.1002/etc.2980
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.2980/full     

Rapid,recurring, structured survey versus bioblitz for generating biodiversity data and analysis with a multispecies abundance model

A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.     

Compliance with and ecosystem function of biodiversity offsets in North American and European freshwaters

Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.     

A palaeo-hydrogeological model for arsenic contamination in southern and south-east Asia

An argument is presented in which areas of natural arsenic contamination of modern groundwaters throughout Asia have a common origin. Arsenic originally accumulated in oceanic ferro-manganoan sediments of the eastern Palaeo-Tethys. This was further concentrated through oceanic crustal extinction in what later became the south-east Chinese accreted mineralised terrain. Proto-Himalayan uplift of this area created the palaeo-drainage systems of the Ganges – Brahmaputra, Irrawaddy, Mekong, and Red Rivers, with consequent headwater erosion of arsenic-rich sediments. Their downstream deposition as immature and easily redistributed Neogene sandstones, silts, and iron-rich clays has created secondary and tertiary reservoirs of adsorbed and authigenic arsenic, from which the current arsenic-rich groundwaters have evolved. Considering river basins within the above palaeo-hydrogeological framework provides a basis for assessing the risk of arsenic in groundwater basins of south and south-eastern Asia.     

Cost‐effective conservation of an endangered frog under uncertainty

How should managers choose among conservation options when resources are scarce and there is uncertainty regarding the effectiveness of actions? Well‐developed tools exist for prioritizing areas for one‐time and binary actions (e.g., protect vs. not protect), but methods for prioritizing incremental or ongoing actions (such as habitat creation and maintenance) remain uncommon. We devised an approach that combines metapopulation viability and cost‐effectiveness analyses to select among alternative conservation actions while accounting for uncertainty. In our study, cost‐effectiveness is the ratio between the benefit of an action and its economic cost, where benefit is the change in metapopulation viability. We applied the approach to the case of the endangered growling grass frog (Litoria raniformis), which is threatened by urban development. We extended a Bayesian model to predict metapopulation viability under 9 urbanization and management scenarios and incorporated the full probability distribution of possible outcomes for each scenario into the cost‐effectiveness analysis. This allowed us to discern between cost‐effective alternatives that were robust to uncertainty and those with a relatively high risk of failure. We found a relatively high risk of extinction following urbanization if the only action was reservation of core habitat; habitat creation actions performed better than enhancement actions; and cost‐effectiveness ranking changed depending on the consideration of uncertainty. Our results suggest that creation and maintenance of wetlands dedicated to L. raniformis is the only cost‐effective action likely to result in a sufficiently low risk of extinction. To our knowledge we are the first study to use Bayesian metapopulation viability analysis to explicitly incorporate parametric and demographic uncertainty into a cost‐effective evaluation of conservation actions. The approach offers guidance to decision makers aiming to achieve cost‐effective conservation under uncertainty.     

Parasitic wasps orient to green leaf volatiles

Summary Undamaged plants emit low levels of green leaf volatiles (GLVs), while caterpillar-damaged and artificially damaged plants emit relatively higher levels of certain GLVs. Female braconid parasitoids,Microplitis croceipes, oriented to both damaged plants and to individual GLVs in no-choice tests in a wind tunnel, but seldom oriented to undamaged plants. Female ichneumonid parasitoids,Netelia heroica, also oriented to individual GLVs in a wind tunnel. Males of both wasp species failed to orient to the GLVs. These data show that leaf-feeding caterpillars can cause the release of GLVs, and that parasitic wasps can respond to these odors by flying upwind (chemoanemotactic response), which brings the wasps to their caterpillar hosts. This supports the hypothesis that plants communicate with members of the third trophic level,i.e., plants under herbivore attack emit chemical signals that guide natural enemies of herbivores to sites of plant damage. In this interaction, the GLVs serve as tritrophic plant-to-parasitoid synomones. That parasitoids from two different wasp families oriented to GLVs suggests that the response may be widespread among the Hymenoptera.Mention of a commercial or proprietary product does not constitute an endorsement by the U.S. Department of Agriculture     

Potential for Electropositive Metal to Reduce the Interactions of Atlantic Sturgeon with Fishing Gear

Atlantic sturgeon (Acipenser oxyrhynchus) populations have been declared either endangered or threatened under the U.S. Endangered Species Act. Effective measures to repel sturgeon from fishing gear would be beneficial to both fish and fishers because they could reduce both fishery‐associated mortality and the need for seasonal and area closures of specific fisheries. Some chondrostean fishes (e.g., sturgeons and paddlefishes) can detect weak electric field gradients (possibly as low as 5 Μv/cm) due to arrays of electroreceptors (ampullae of Lorenzini) on their snout and gill covers. Weak electric fields, such as those produced by electropositive metals (typically mixtures of the lanthanide elements), could therefore potentially be used as a deterrent. To test this idea, we recorded the behavioral responses of juvenile Atlantic sturgeon (31–43 cm fork length) to electropositive metal (primarily a mixture of the lanthanide elements neodymium and praseodymium) both in the presence and absence of food stimuli. Trials were conducted in an approximately 2.5 m diameter × 0.3 m deep tank, and fish behaviors were recorded with an overhead digital video camera. Video records were subsequently digitized (x, y coordinate system), the distance between the fish and the electropositive metal calculated, and data summarized by compiling frequency distributions with 5‐cm bins. Juvenile sturgeon showed clear avoidance of electropositive metal but only when food was present. On the basis of our results, we conclude that the electropositive metals, or other sources of weak electric fields, may eventually be used to reduce the interactions of Atlantic sturgeon with fishing gear, but further investigation is needed. El Potencial del Metal Electropositivo para Reducir las Interacciones del Esturión Atlántico con Instrumentos de Pesca Bouyoucos, Bushnell & Brill 13–003     

The role of time and species identities in spatial patterns of species richness and conservation

Many conservation actions are justified on the basis of managing biodiversity. Biodiversity, in terms of species richness, is largely the product of rare species. This is problematic because the intensity of sampling needed to characterize communities and patterns of rarity or to justify the use of surrogates has biased sampling in favor of space over time. However, environmental fluctuations interacting with community dynamics lead to temporal variations in where and when species occur, potentially affecting conservation planning by generating uncertainty about results of species distribution modeling (including range determinations), selection of surrogates for biodiversity, and the proportion of biodiversity composed of rare species. To have confidence in the evidence base for conservation actions, one must consider whether temporal replication is necessary to produce broad inferences. Using approximately 20 years of macrofaunal data from tidal flats in 2 harbors, we explored variation in the identity of rare, common, restricted range, and widespread species over time and space. Over time, rare taxa were more likely to increase in abundance or occurrence than to remain rare or disappear and to exhibit temporal patterns in their occurrence. Space–time congruency in ranges (i.e., spatially widespread taxa were also temporally widespread) was observed only where samples were collected across an environmental gradient. Fifteen percent of the taxa in both harbors changed over time from having spatially restricted ranges to having widespread ranges. Our findings suggest that rare species can provide stability against environmental change, because the majority of species were not random transients, but that selection of biodiversity surrogates requires temporal validation. Rarity needs to be considered both spatially and temporally, as species that occur randomly over time are likely to play a different role in ecosystem functioning than those exhibiting temporal structure (e.g., seasonality). Moreover, temporal structure offers the opportunity to place management and conservation activities within windows of maximum opportunity.     

Main nutrient compounds in food bodies of Mexican <Emphasis Type="Italic">Acacia</Emphasis> ant-plants

Summary. Myrmecophytic plants use obligate ant mutualists as a constitutive indirect defence mechanism. These plants often produce cellular food bodies (FBs) to nourish their resident ants. Lipids, proteins, and even highly specialised compounds such as glycogen have been reported from FBs, but detailed chemical analyses of FB composition have so far been presented only for Southeast Asian Macaranga and Central American Piper myrmecophytes. Here we report the chemical composition of FBs of five myrmecophytic Acacia (Fabaceae) species from Mexico using HPLC (carbohydrates and proteins) and GC-MS (lipids). Feeding experiments revealed no hints on any use of external food sources by the inhabiting Pseudomyrmex ants. These ants obviously rely completely on FBs and extrafloral nectar provided by their hosts. The total content of nutrients in Acacia FBs was 15-25% of FB dry mass, being much lower than in Macaranga or Piper FBs. Proteins were dominating (8-14 % dm) in Acacia FBs and thus were present in higher amounts than in Macaranga FBs, yet in lower amounts than in Piper. Lipids contributed 1-9 % of dry mass, showing a lower proportion than in FBs of Macaranga or Piper. Carbohydrates made up 3-11 % dm, reaching in most Acacia species the same range as observed in Macaranga and in Piper FBs. Water content was 18-24 % of FB fresh mass, and structural tissue obviously made up a much higher proportion in Acacia FBs than in Macaranga or Piper FBs. Both characters might represent an adaptation to producing FBs unprotected at the leaf tips under dry conditions. Acacia FBs contain all amino acids and all fatty acids that are considered essential for insects, and their contents of lipids and proteins are higher than in the leaves from which they are ontogenetically derived. This indicates a putatively adaptive enrichment of nutritionally valuable compounds in structures functioning as ant-food.     

Examining the uncertain origin and management role of martens on Prince of Wales Island,Alaska

Conservation biologists are generally united in efforts to curtail the spread of non‐native species globally. However, the colonization history of a species is not always certain, and whether a species is considered non‐native or native depends on the conservation benchmark. Such ambiguities have led to inconsistent management. Within the Tongass National Forest of Alaska, the status of American marten (Martes americana) on the largest, most biologically diverse and deforested island, Prince of Wales (POW), is unclear. Ten martens were released to POW in the early 1930s, and it was generally believed to be the founding event, although this has been questioned. The uncertainty surrounding when and how martens colonized POW complicates management, especially because martens were selected as a design species for the Tongass. To explore the history of martens of POW we reviewed other plausible routes of colonization; genetically and isotopically analyzed putative marten fossils deposited in the late Pleistocene and early Holocene to verify marten occupancy of POW; and used contemporary genetic data from martens on POW and the mainland in coalescent simulations to identify the probable source of the present‐day marten population on POW. We found evidence for multiple routes of colonization by forest‐associated mammals beginning in the Holocene, which were likely used by American martens to naturally colonize POW. Although we cannot rule out human‐assisted movement of martens by Alaskan Natives or fur trappers, we suggest that martens be managed for persistence on POW. More generally, our findings illustrate the difficulty of labeling species as non‐native or native, even when genetic and paleo‐ecological data are available, and support the notion that community resilience or species invasiveness should be prioritized when making management decisions rather than more subjective and less certain conservation benchmarks.