Field validation of laboratory-derived IOBC toxicity ratings for natural enemies in commercial vineyards

Management of pests and diseases remains a key issue for agricultural profitability and environmental health. Moves towards sustainability require a reduction in chemical toxicity loadings and conservation of natural enemies to maintain pest control. There is a lot of information from laboratory tests regarding the effects of chemicals on beneficial predators and parasitoids but very few translations of these effects into field impacts particularly under commercial conditions. To address this issue we calculated a chemical toxicity score for 19 commercial vineyards based on IOBC toxicity ratings and application number, and compared this to extensive field collections to determine if natural enemy populations can be related to predicted toxicity loadings. Invertebrates were sampled four times during the growing season using canopy sticky traps and ground level pitfall traps. Ordination analyses using non-metric multidimensional scaling indicated community structure in vineyards correlated to site chemical use, while principal components analyses identified the taxa involved. One ordination axis from canopy data and two axes from ground level data were correlated to overall IOBC ratings for the vineyards. Principal components analyses indicated that spiders, lacewings, carabids and parasitoids were all affected by chemical use. IOBC rating based on laboratory studies therefore correlated with chemical effects on field populations of natural enemies in commercial vineyards where complexes of pesticides were applied. The use of chemicals with low toxicity to beneficials as predicted by IOBC ratings will contribute to preservation and maintenance of natural enemies in vineyard ecosystems.     

Fifty years later: The sequence, structure and function of lacewing cross-beta silk

Classic studies of protein structure in the 1950s and 1960s demonstrated that green lacewing egg stalk silk possesses a rare native cross-beta sheet conformation. We have identified and sequenced the silk genes expressed by adult females of a green lacewing species. The two encoded silk proteins are 109 and 67 kDa in size and rich in serine, glycine and alanine. Over 70% of each protein sequence consists of highly repetitive regions with 16-residue periodicity. The repetitive sequences can be fitted to an elegant cross-beta sheet structural model with protein chains folded into regular 8-residue long beta strands. This model is supported by wide-angle X-ray scattering data and tensile testing from both our work and the original papers. We suggest that the silk proteins assemble into stacked beta sheet crystallites bound together by a network of cystine cross-links. This hierarchical structure gives the lacewing silk high lateral stiffness nearly threefold that of silkworm silk, enabling the egg stalks to effectively suspend eggs and protect them from predators.     

Benefits of living underground: the case of parasite release in the antlion Myrmeleon timidus

The omnipresence of pathogens makes them a strong selective pressure for most organisms, generating a variety of defensive responses to fight them. One mechanism by which organisms can release this pressure is avoidance of the pathogens in a spatial or temporal context. To date, only a few biological systems provide evidence that habitat selection can favour an escape from pathogens. An abiotic factor that varies across habitats and influences the evolution of host life history is humidity, which correlates positively with pathogen levels in the environment. Entomopathogenic fungi are abundant in soils and are obligate killers that require humidity for host infection. Antlions (Neuroptera: Myrmeleontidae) are typical soil-dwelling insects that can live several years as larvae, buried in dry and fine substrates where they build their traps. This lifestyle may release them from selective pressure by entomopathogenic fungi. Here, we investigated whether living underground provides protection against the generalist entomopathogenic fungus Beauveria bassiana (Bals.-Criv.) Vuill. in the antlion Myrmeleon timidus Gerstaecker under low or high humidity in the environment. Individuals that were inoculated with the fungus showed greater survival rates when buried in dry sand compared to individuals that were kept half-buried or without sand, with similar outcomes across humidity levels. Given that the diversity of antlions is higher in arid environments, this benefit obtained from pit-building behaviour seems to be a coincidental by-product of this foraging strategy, which would be particularly beneficial in environments where fungal pathogens are common.     

Yellow mutant of the Neotropical green lacewing Chrysoperla externa: trait inheritance and predator performance

The Neotropical green lacewing Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) is a key predator of various small soft‐bodied pest species. Chrysopidae species are known as ‘green lacewings’ due to their overall green body coloration. However, yellow mutant individuals were observed emerging from our lacewing rearing colony. Thus, the mode of inheritance of the yellow trait was studied and the hypothesis of an autosomal recessive allele for yellow color was tested using hybridization and backcrossing techniques. Furthermore, the possible implications of this color variation on specific life‐history characteristics of C. externa and the predation rates of each morph were evaluated. In both yellow and green morphs, basic life‐history characteristics were monitored, including time to hatching and viability of eggs, duration, and viability of larval and pupal stages, emergence rate and survivorship of adults, and fecundity and longevity of females. The yellow and green morphs were indistinguishable with respect to all life‐history traits evaluated and the predation rate of their larvae. Crossing experiments revealed the yellow color to be caused by a homozygous recessive allele, without sex‐linked expression. We conclude that the allele for yellow color is occurring at high frequency in the laboratory colony, supporting the existence of a genetic polymorphism for body ground color.     

Behavioral thermoregulation inpalmipenna aeoleoptera (neuroptera): Do the hypertrophied hindwings play a role?

The hypertrophied hindwings of Palmipenna aeoleoptera (Neuroptera) were examined for a possible thermoregulatory role. These wings arise from basal stalks which expand into large, flattened, darkly pigmented, and vascularized dilations. During the cooler times of the day the insects basked by crouching with the body and hindwings held horizontally in contact with rocks. As air temperatures increased, insects stilted with the hindwings held at 90° to the horizontal. Thoracic temperatures of these ectotherms correlated with air temperatures (T_thorax = 1.55T_air –10.99), with maximum recorded thoracic temperatures of 47°C. No differences were found between thoracic temperatures of males and those of females, although males had far larger hindwings. Live insects caught on rocks were consistently cooler than dead insects (operational temperature thermometers) on rocks. This may be attributed to convective cooling in flight just prior to capture, and stilting, behavior patterns that were frequent during the hottest times of the day. Thoracic temperatures of insects resting on rocks were frequently higher than operational temperature thermometers in air, suggesting that warming resulted from basking on rocks. The minimum body temperature for flight was 27°C. In the laboratory, hindwing ablation altered neither the rate (using time constants) of heating or cooling nor the equilibrium temperature of the body, showing that the hindwings play no direct role in heat uptake or loss.     

中国新记录——囊粉蛉属及一新种记述（脉翅目：粉蛉科）

Genus Aleuropteryx Loew is first recorded from China, and Aleuropteryx sinica sp. nov. is described as new to science. All the type specimens are deposited in the Insect Collections of China Agricultural University, Beijing, China.     

粉蛉亚科中国二新记录属与二新种（脉翅目：粉蛉科）

本文报导粉蛉亚科Ｃｏｎｉｏｐｔｅｒｙｇｉｎａｅ中国２新记录属；匣粉蛉属ＴｈｅｃｏｓｅｍｉｄａｌｉｓＭｅｉｎａｎｄｅｒ和半粉蛉属ＨｅｍｉｓｅｍｉｄａｌｉｓＭｅｉｎａｎｄｅｒ及２新种：杨氏匣粉蛉Ｔ．ｙａｎｇｉＬｉｕ和中华半粉蛉Ｈ．ｓｉｎｅａｓｉｓＬｉｕ。模式标本保存于北京农业大学昆虫标本馆。     

中国粉蛉属四种雌虫的分类学研究(脉翅目:粉蛉科)

对粉蛉科雌虫的分类研究方法进行了初步摸索,并对阿氏粉蛉Coniopteryx(Coniopteryx)aspoecki Kis,1967、圣洁粉蛉Coniopteryx(Coniopteryx)pygmaea Enderlein,1906、斜突粉蛉 Coniopteryx(Coniopteryx)plagiotropa Liu et Yang, 1997、周氏粉蛉Coniopteryx (Coniopteryx) choui Liu et Yang,1998的雌虫内生殖器结构特征进行了描述和绘图。     

贵州省草蛉区系的研究：（脉翅目：草蛉科）

贵州省草蛉缺乏系统调查研究,现根据北京农业大学和中国科学院动物研究所的收藏,鉴定了8属16种草蛉,以检索表形式附以贵州省的分布,其中包括5新种和1个新异名,并调整了4个新组合种,新种的模式标本保存在北京农业大学昆虫标本室。