To have and not to have sex: When multiple evolutions of conditional use of sex elegantly solve the question in the ant genus Cataglyphis

Organisms use an amazingly large diversity of mechanisms to pass on their genes to the next generation. Sex is ancestral in eukaryotes, where it remains the most widespread way of reproduction. By combining one's genes with those of a partner, sex entails a dilution of one's genes at each generation. Evolution has been particularly creative in devising mechanisms allowing females to avoid this dilution, from classical parthenogenesis to the elimination of male genes after fertilization (Bell, 1982). Moreover, the term parthenogenesis includes various forms. Parthenogenesis can be used for female (thelytoky) or male (arrhenotoky) production and it can be associated with different cytological mechanisms, from strict clonality to meiotic division with the fusion of two of the four products of meiosis to restore diploidy (Suomalainen, Saura, & Lokki, 1987). Understanding the evolution of these diverse reproductive systems remains one of the most exciting and longstanding questions in evolutionary biology. By characterizing the reproductive systems of 11 species from the thermophilic ant genus Cataglyphis, in this issue of Molecular Ecology, Kuhn, Darras, Paknia, and Aron (2020) show the high lability of parthenogenesis, with multiple independent evolution of facultative thelytoky from sexual ancestors. The diversity of life history traits and social characteristics of this genus (e.g., mode of colony foundation, female polyandry) provides a unique and exciting opportunity to investigate the social and environmental factors driving the evolution of reproductive systems in social Hymenoptera.     

罗汉果叶片挥发性成分与访花昆虫: 雌雄株差异及其生态影响

为探究罗汉果(Siraitia grosvenorii)自然授粉不良的形成原因,该文以罗汉果品种“大地二号”的种苗为材料,采用定点定时方法调查罗汉果雌雄株访花昆虫,同时利用GC-MS对雌雄株叶片的挥发性成分进行比较分析。结果表明:在雄株上观察到访花昆虫102种,分属于8目29科,其中包括蜜蜂科、眼蝶科、夜蛾科和天蛾科等传粉昆虫类群; 在雌株上观察到访花昆虫69种,分属于7目16科,但未观察到上述传粉昆虫类群。雄株访花昆虫的物种丰富度、多度和Shannon-Wiener多样性均显著高于雌株(P<0.05),Jaccard相似性分析显示,雌株和雄株访花昆虫达到中等不相似水平。在雄株叶片中鉴定出挥发性成分17种,优势成分为萜烯类化合物,占总含量的67.31%; 在雌株叶片中鉴定出挥发性成分12种,优势成分为烷烃类化合物,占总含量的44.27%。雄株具有较多特有成分,包括7种萜烯类和3种酯类成分,占总体成分的45.45%; 雌株的特有成分较少,包括4种烷烃类和1种酯类成分,占总体成分种类的22.72%。Jaccard相似性分析显示,雌株和雄株的挥发性成分总体上达到中等不相似水平,其中萜烯类和酯类的相似度更低,达到极不相似水平。进一步分析表明,在罗汉果雌雄株之间,由于挥发性化合物在优势成分上的重要差异,以及特有成分的大量存在,可能导致了它们访花昆虫类群的显著差异,进而影响了罗汉果的自然传粉过程。     

基于基因组挖掘的农抗120活性成分制霉菌素和丰加霉素的发现和鉴定

【目的】分析刺孢吸水链霉菌北京变种(农抗120产生菌)基因组和次级代谢产物组分,研究并鉴定农抗120产生菌中未被发现的活性组分。【方法】利用antiSMASH在线分析农抗120产生菌Streptomyces hygrospinosusvar.beijingensis基因组信息,锁定可能的制霉菌素和丰加霉素生物合成基因簇。利用HPLC和LC-MS等分析方法对农抗120产生菌发酵产物进行分析,同时利用制霉菌素和丰加霉素标准品作为对照,以鉴定该菌株代谢组分中的次级代谢产物。此外,通过构建目标基因簇大片段缺失突变株,并对所得突变株发酵产物进行检测,以确定生物合成基因簇与目的代谢产物的对应关系。【结果】本研究综合利用基因组序列分析、基因缺失突变株构建以及代谢产物检测方法,鉴定了农抗120产生菌中制霉菌素和丰加霉素两种活性成分,并确定了负责这些化合物合成的基因簇。【结论】本研究所构建的多重基因簇失活突变株为挖掘刺孢吸水链霉菌北京变种更多的天然次级代谢产物奠定了基础。     

Student‐led field studies of herbivory: Hands‐on experiences for remote (or in‐person) learning

Challenging students to independently design and implement experiments is a powerful way to teach the scientific method while engaging with STEM‐related course material. For ecology and organismal biology, such experiences often take the form of field work. The COVID‐19 pandemic presented formidable challenges for instructors of such courses: How can students conduct any experiments, much less ones of their own design, when they might not even have access to campus? Here we describe a student‐led field project exploring invertebrate herbivory in terrestrial plant systems. Designed to flexibly accommodate student groups working either in‐person, remotely, or both, the project would be suitable for invertebrate biology, plant biology, or general ecology courses at the college or high school level. We describe our implementation in two sections of a sophomore‐level course, provide specific advice based on our experiences, make suggestions for future improvements or adaptations, and provide all the written materials that instructors would need to implement this in their own teaching.     

DNA barcodes as a tool in biodiversity research: testing pre-existing taxonomic hypotheses in Delphic Apollo butterflies (Lepidoptera,Papilionidae)

Numerous studies have demonstrated that DNA barcoding is an effective tool for detecting DNA clusters, which can be viewed as operational taxonomic units (OTUs), useful for biodiversity research. Frequently, the OTUs in these studies remained unnamed, not connected with pre-existing taxonomic hypotheses, and thus did not really contribute to feasible estimation of species number and adjustment of species boundaries. For the majority of organisms, taxonomy is very complicated with numerous, often contradictory interpretations of the same characters, which may result in several competing checklists using different specific and subspecific names to describe the same sets of populations. The highly species-rich genus Parnassius (Lepidoptera: Papilionidae) is but one example, such as several mutually exclusive taxonomic systems have been suggested to describe the phenotypic diversity found among its populations. Here we provide an explicit flow chart describing how the DNA barcodes can be combined with the existing knowledge of morphology-based taxonomy and geography (sympatry versus allopatry) of the studied populations in order to support, reject or modify the pre-existing taxonomic hypotheses. We then apply this flow chart to reorganize the taxa within the Parnassius delphius species group, solving long-standing taxonomic problems.     

Towards greater realism in inclusive fitness models: the case of worker reproduction in insect societies

The conflicts over sex allocation and male production in insect societies have long served as an important test bed for Hamilton''s theory of inclusive fitness, but have for the most part been considered separately. Here, we develop new coevolutionary models to examine the interaction between these two conflicts and demonstrate that sex ratio and colony productivity costs of worker reproduction can lead to vastly different outcomes even in species that show no variation in their relatedness structure. Empirical data on worker-produced males in eight species of Melipona bees support the predictions from a model that takes into account the demographic details of colony growth and reproduction. Overall, these models contribute significantly to explaining behavioural variation that previous theories could not account for.     

Overwintering sparrow use of field borders planted as beneficial insect habitat

Field borders are an effective conservation strategy for providing habitat to overwintering sparrows, and may be a venue through which beneficial insect populations are promoted. However, traditional fallow field borders lack sufficient pollen and nectar sources required to sustain beneficial insect populations; therefore, borders planted to a mix of native prairie flowers and grasses may be needed if increases in beneficial insect populations are desired. Although the value of fallow borders to birds has been established, little is known about bird use of beneficial insect habitats. Using single-observer transect surveys, we compared overwintering sparrow densities among 4 field border treatments (planted native warm season grasses and prairie flowers, planted prairie flowers only, fallow, and mowed) replicated around 9 organic crop fields from November to March 2009–2010 and 2010–2011. Sparrow densities were 5–10 times lower in mowed borders than in other border treatments in 2009–2010 and 2010–2011, but did not differ among planted and fallow borders in either year. Planted field borders may be a useful conservation practice for providing habitat for both overwintering sparrows and beneficial insects. © 2012 The Wildlife Society.     

Description of the larva of Kempnyia colossica (Navás) (Plecoptera: Perlidae) with biological notes

In this paper, the larva of Kempnyia colossica (Navás 1934) is described based on material collected in Parque Estadual Intervales, São Paulo State, and biological notes are presented.     

秸杆纤维素高效降解菌

我国是农业大国,秸秆纤维素资源非常丰富,而对它的开发利用却十分有限,造成了资源的极大浪费.若能将这些纤维废弃物转化为简单糖类或蛋白质等产品,既可以解决环境污染问题,又可以作为饲料,缓解粮食短缺以及能源危机对当前社会的影响,所以国内外对微生物分解转化纤维素的研究极为重视.目前研究较多的是霉菌,尤以绿色木霉、里氏木霉和康氏木霉为典型.但木霉等霉菌类真菌在培养过程中产生酸败霉腐气味,并具有一定毒性,且产酶周期通常都比较长,这使其在食品酿造和饲料发酵等工业生产中的应用受到较大的限制.芽孢杆菌因具有很好的稳定性和环境适应性、易工业化生产等优点而备受欢迎,因此高产降解纤维素芽孢杆菌的获得能够得到比较稳定的菌剂,便于工农业上的应用,对解决当今世界所面临的粮食短缺、饲料资源紧张、能源危机和环境污染等问题具有深远的意义.