Post‐hibernation ovary development in queens of the Japanese giant hornet Vespa mandarinia (Hymenoptera: Vespidae)

Ovary contents and insemination status were examined in overwintered queens of Vespa mandarinia that were collected using bait traps in Ibaraki Prefecture, eastern Japan. Catches in the traps occurred from late April to early July in 1999, though they were few or rather sporadic in and after June. Fertilization rates were 100% in 1999, and 93% in 1998 when a preliminary sampling was made. While the ovary index (number of eggs with size equal to or larger than adjacent nurse cells) of queens caught on the first few collection dates was small, it rapidly increased up to late May. Generalized linear model analyses showed that the ovary index depended both on collection date and the size (head width) of the queens. Mature eggs were almost absent in their ovaries before early May, whereas more than 70% of the queens had one or more mature eggs on and after May 10, suggesting the onset of nesting in early May.     

不同取样方式在稻田节肢动物采集中的效率评估

水稻是我国主要粮食作物,每年都会因虫害造成大量的经济损失,为了挽回害虫造成的损失,必须对害虫进行防治。田间节肢动物群落调查是评价害虫防治效果的重要依据,取样方式对节肢动物群落调查的准确性具有重要的影响。另外,对转基因作物对稻田生物多样性安全性进行评价时,取样方式对多样性评价的准确性也具有重要的影响。本文采用吸虫器法、盆拍法和马氏网诱集法3种取样方式进行稻田节肢动物调查,并评估不同取样方式的采集效率。得到的结果有:1.采集到的节肢动物物种数:马氏网诱集法吸虫器法盆拍法;2.采集的节肢动物数量:盆拍法吸虫器法马氏网诱集法;3.吸虫器取样法在调查叶蝉科、秆蝇科、茧蜂科、姬蜂科、金小蜂科、缘腹细蜂科、蕈蚋科时,取样效率较高;4.盆拍取样法在调查叶蝉科、瘿蚊科、微蛛亚科、跳蛛科、狼蛛科、猫蛛科、弹尾虫目、飞虱科时,取样效率较高;5.马氏网诱集法在调查缟蝇科和毛蠓科时取样效率较高。马氏网诱集法善于采集具有飞行能力的节肢动物;吸虫器法对不同习性的节肢动物采集效果均较高;盆拍法适合采集活动于水稻基部的节肢动物。     

Bioinsecticide and leaf litter combination increases oviposition and reduces adult recruitment to create an effective ovitrap for Culex mosquitoes

Mosquito egg traps, aquatic habitats baited with oviposition attractant and insecticide, are important tools for surveillance and control efforts in integrated vector management programs. The bioinsecticide Bacillus thuringiensis subsp. israelensis (Bti) is increasingly used as an environmentally friendly alternative to chemical insecticides and the combination of Bti with a simple oviposition attractant like leaf litter to create an effective egg trap seems appealing. However, previous research suggests that Bti may itself alter oviposition, and that leaf litter may dramatically reduce Bti toxicity. Here we present results from field experiment designed to link the effects of litter and Bti on mosquito oviposition habitat selection and post‐colonization survival to production of adult mosquitoes. Tripling litter increased Culex spp. oviposition nearly nine‐fold, while Bti had no effect on oviposition. Neither factor altered egg survival, thus larval abundance reflected the effects of litter on oviposition. Both Bti and litter reduced larval survival by ～60%. We found no evidence that increased litter reduced Bti toxicity. Adult production was dependent upon both litter and Bti. In the absence of Bti, effects of litter on oviposition translated into three‐fold more adults. However, in the presence of Bti, initial increases in oviposition were erased by the combined negative effects of Bti and litter on post‐colonization survival. Thus, our study provides field evidence that combined litter and Bti application creates an effective ovitrap. This combined treatment had the highest oviposition and the lowest survival, and thus removed the greatest number of mosquitoes from the landscape.     

Optical traps: shedding light on biological processes

Optical traps exploit the radiation forces of laser light to manipulate microscopic particles. The ability to manipulate biological material and quantify the force required has been exploited in the biosciences; from the isolation of single cells to kinetic measurements of single motor molecules. This review describes the theory of optical trapping and using recent publications gives examples of how it has been employed across a broad spectrum of biological research.     

Evaluation of infestation percentage of cotton fields to the spiny bollworm,Earias insulana Boisduval (Lep.: Noctuidae), and its relationship with pheromone traps

Spiny bollworm, Earias insulana Boisduval (Lepidoptera: Noctuidae), is one of the most important pest of malvaceous plants throughout the world, except America. In recent years, this insect has been serious pest for cotton fields in southern regions of Iran, especially Darab region of Fars province. In order to evaluate the performance of sex pheromone in reduction of infestation percentage of the spiny bollworm by mass trapping method, an experiment was carried out during year of 2012 in Darab region in Randomised Completely Block Design with six treatments and four replications. The treatments were: application of the four sex pheromone trap densities at the rates of 16, 20, 24 and 30?traps/h, application of Larvin chemical insecticide at the rate of 1?L/h and control. Percentages of infected bolls and flowers to E. insulana were weekly determined. The application of Larvin insecticide performed as the pest population reached to economic threshold level. Analysis variance of results showed that there are significant differences between time, trap number and time?×?trap interaction on infestation percentage per hectare. During sampling time, the highest infestation percentage was in control treatment and the lowest one was observed in 30 and 24?traps/h treatments. The peak of infestation percentage was seen in 18th of November. The best efficiency among treatments was observed in pheromone trap. In conclusion, using sex pheromone trap in comparison to application of insecticides can efficiently reduce infestation level of cotton fields.     

Population dynamics of aphid species in Korean seed potato cultivation area over four decades

The world's climate is changing. This can affect agricultural insects and the damage they cause by altering their ecology, behavior and habitats. Aphids are emerging as an indicator of climate change, and they are a good model for understanding these environmental changes, especially based on their migratory behavior. In this study, the occurrence of aphids in a seed potato field in Pyeongchang, Korea, was monitored daily using a yellow water pan trap from 1977 to 2017. During these 40 years, the annual migration fluctuations of the aphids were analyzed, with particular focus on four species known to vector potato viruses, Aphis gossypii, Aulacorthum solani, Macrosiphum euphorbiae, and Myzus persicae. It was found that, as time goes by, the start point of spring migration in these aphid species was getting earlier while the peak in autumn migration gradually moved to the winter season. Moreover, the annual total number of collected aphids increased by 3.74 times during the 40 years. Together with a mean annual temperature increase of 1.03°C in Pyeongchang over the past four decades, there is a potential threat of expansion in the distribution of aphid species. Therefore, we carefully hypothesized that this temperature change could influence the aphid's population changes in the Korean peninsula. This information can be used in an integrated aphid management program in seed potato cultivation.     

Pichia stipitis OYE 2.6 variants with improved catalytic efficiencies from site-saturation mutagenesis libraries

An earlier directed evolution project using alkene reductase OYE 2.6 from Pichia stipitis yielded 13 active site variants with improved properties toward three homologous Baylis–Hillman adducts. Here, we probed the generality of these improvements by testing the wild-type and all 13 variants against a panel of 16 structurally-diverse electron-deficient alkenes. Several substrates were sterically demanding, and as hoped, creating additional active site volume yielded better conversions for these alkenes. The most impressive improvement was found for 2-butylidenecyclohexanone. The wild-type provided less than 20% conversion after 24 h; a triple mutant afforded more than 60% conversion in the same time period. Moreover, even wild-type OYE 2.6 can reduce cyclohexenones with very bulky 4-substituents efficiently.     

Identification of a large SNP dataset in Larimichthys crocea using specific‐locus amplified fragment sequencing

The large yellow croaker, Larimichthys crocea, is a commercially important drum fish (Family: Sciaenidae) native to the East and South China Sea. Habitat deterioration and overfishing have led to significant population decline and the collapse of its fishery over the past decades. Today, the market supply of L. crocea depends solely on stocks produced in hatcheries and farms. Common issues that occur in the culture of L. crocea include germplasm degradation, precocious puberty, elevated disease susceptibility and growth retardation. In this study, we employed SLAF‐seq (specific‐locus amplified fragment sequencing) technology to identify single nucleotide polymorphism (SNP) loci across the L. crocea genome. Sixty samples were selected for SLAF analysis out of 1000 progeny in the same cohort of a cultured stock. Our analysis obtained a total of 151 253 SLAFs, of which 65.88% (99 652) were identified to be polymorphic, scoring a total of 710 567 putative SNPs. Further filtration resulted in a final panel of 1782 SNP loci. The data derived from this work could be beneficial for understanding the genetics of complex phenotypic traits as well as for developing marker‐selection‐assisted breeding programs in L. crocea.     

Diversity and seasonal fluctuations in dung beetle (Coleoptera) community in Kurukshetra,India

Five pitfall traps baited with 150–200 g of fresh cattle dung were installed for 24 h at weekly intervals. A total of 991 dung beetles from 11 genera, 31 species and three subfamilies was obtained. The community was dominated by Oniticellus spinipes individuals by 32.3%. Ten species appeared only once during the collection period and species composition and dominance changed throughout the period. The overall pattern we detected in the organization of the dung beetle community is that the species richness, abundance and diversity rise in September and the 2^nd week of October. The dung beetle community was found to be affected by season.     

Six New Species of Dobsonflies from Venezuela (Megaloptera: Corydalidae: Corydalinae)

Six new species of dobsonflies (Megaloptera: Corydalidae: Corydalinae) from Venezuela are described and illustrated, two in the Neotropical genus Chloronia and four within the New World genus Corydalus. Chloronia contains 15 previously described species. The new species Chloronia gaianii and C. marthae, each from the southern tepui and Andean regions, appear to be most closely related to C. hieroglyphica (Rambur) and C. mirifica Navás, respectively. Corydalus contains 30 previously described species. The new species Corydalus clavijoi, of Andean affinity, appears most closely related to C. tesselatus Stitz; C. crossi, from Auyán-tepuí, might be closely related to C. nubilus Erichson; and both C. hayashii and C. mayri, from westernmost Guayana Shield area and Aracamuni tepuis, respectively, clearly belong in the distinct and monophyletic C. arpi Navás species group. Keys for identification of the Venezuelan species of both genera are provided.