Molecular identification and expression analysis of magnetic receptor in Spodoptera frugiperda (Lepidoptera: Noctuidae), an invasive species in China

The fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera, Noctuidae), has emerged as a highly invasive pest globally in the past decade due to its remarkable migratory capabilities. Magnetic receptors play an important role in the migration and navigation of the animal, but little is known about the molecular mechanism of the magnetic receptors of S. frugiperda (SfMagR). In this study, we successfully cloned the cDNA encoding SfMagR, which has a 396 bp of open reading frame (ORF) encoding 132 amino acids. Phylogenetic analysis revealed a high conservation of magnetic receptors among various animal species, notably demonstrating a 98.4% sequence identity between S. frugiperda and Spodoptera litura, and a 70.3% identity with Homo sapiens, a vertebrate species. Expression analysis conducted across different developmental stages demonstrated SfMagR expression in the egg, larval, and pupal stages of the moth, but exhibited predominate expression in the adult stage, particularly in male adults. Moreover, the tissue expression profile indicated that SfMagR expression primarily occurred within the thorax of the moth, specifically in the thorax excluding the legs and wings. These findings not only provide fundamental data and a molecular foundation for future investigations into the function of SfMagR, but also offer valuable insights for the future management of invasive species.     

Taxonomic notes on three species of Herposiphonia (Ceramiales, Rhodophyta) found in Japan

Three species of the red algal genus Herposiphonia (Ceramiales, Rhodomelaceae) found in Japan are described, and taxonomic features of the genus are discussed. Herposiphonia crassa Hollenberg is reported from Japan for the first time and is characterized by thick axes (200–350 µm in diameter) and determinate branches (100–200 µm in diameter), relatively short determinate laterals (400–1200 µm in length) with a large number of periaxial cells (15–19 per segment) and three (occasionally two or four) vigorously developed (1.8–2.5 mm in length by 50–75 µm in diameter basally) trichoblasts on each determinate lateral. Herposiphonia elongata Masuda et Kogame is also reported from Japan for the first time and is characterized by the conspicuous thickening growth of cystocarp‐bearing branches and spermatangial branches with an elongated sterile tip. Some newly found features of Herposiphonia fissidentoides (Holmes) Okamura are presented: the rhizoid production from the central portion of parental periaxial cells in addition to the distal end, virtual absence of vegetative trichoblasts, production of procarpial trichoblasts and spermatangial branches on fertile determinate branches on short indeterminate laterals, cystocarps sometimes with a short spur, and extremely large tetrasporangia.     

Utilizing the assassin bug, Pristhesancus plagipennis (Hemiptera: Reduviidae), as a biological control agent within an integrated pest management programme for Helicoverpa spp. (Lepidoptera: Noctuidae) and Creontiades spp. (Hemiptera: Miridae) in cotton

Helicoverpa spp. and mirids, Creontiades spp., have been difficult to control biologically in cotton due to their unpredictable temporal abundance combined with a cropping environment often made hostile by frequent usage of broad spectrum insecticides. To address this problem, a range of new generation insecticides registered for use in cotton were tested for compatibility with the assassin bug, Pristhesancus plagipennis (Walker), a potential biological control agent for Helicoverpa spp. and Creontiades spp. Indoxacarb, pyriproxifen, buprofezin, spinosad and fipronil were found to be of low to moderate toxicity on P. plagipennis whilst emamectin benzoate, abamectin, diafenthiuron, imidacloprid and omethaote were moderate to highly toxic. Inundative releases of P. plagipennis integrated with insecticides identified as being of low toxicity were then tested and compared with treatments of P. plagipennis and the compatible insecticides used alone, conventionally sprayed usage practice and an untreated control during two field experiments in cotton. The biological control provided by P. plagipennis nymphs when combined with compatible insecticides provided significant (P<0.001) reductions in Helicoverpa and Creontiades spp. on cotton and provided equivalent yields to conventionally sprayed cotton with half of the synthetic insecticide input. Despite this, the utilization of P. plagipennis in cotton as part of an integrated pest management programme remains unlikely due to high inundative release costs relative to other control technologies such as insecticides and transgenic (Bt) cotton varieties.     

Potentialities of methoxyfenozide for the integrated management of Helicoverpa armigera (Lepidoptera: Noctuidae) on cotton in Benin,West Africa

Intensive use of chemical insecticides against Helicoverpa armigera has led to the development of resistance to the major chemical families of insecticides. Consequently, management of H. armigera using conventional chemical insecticides is increasingly difficult. Methoxyfenozide is an agonist of the insect moulting hormone 20-hydroxyecdysone that acts faster than chitin synthesis inhibitors. The present work is aimed to assess the effectiveness of methoxyfenozide for use against H. armigera on cotton in Benin, West Africa. Laboratory tests and field experiments have been carried out. For laboratory studies, topical application of methoxyfenozide was done using L2 and L5 instar larva of H. armigera. Tested methoxyfenozide concentrations varied from 24 μl/ml to 144 μl/ml and the control is water only. For field experiments, a complete randomised block design was used with methoxyfenozide (72 μl/ml) and a control (no spraying). Berthoud Ultra Low Volume sprayer was used to spray methoxyfenozide suspension at 60-l per hectare. Two sprays were applied, 7 days apart. Laboratory tests indicated that 24 h after application of methoxyfenozide, about 100% of treated L2 and L5 larva were morbid or dead compared with 0% for the control larva. There are no significant differences between tested concentrations. Morbid larvae died within 2 days. In field experiments, cotton yield harvested on methoxyfenozide treated plants was double of that obtained on untreated plants (9375 kg and 4875 kg per hectare respectively). Thus methoxyfenozide may be used as component of Integrated Pest Control Programme on cotton in Benin, West Africa.     

诊断引物应用于我国三种重要赤眼蜂分子鉴定的研究

本研究根据螟黄赤眼蜂rDNA-ITS2序列设计了螟黄赤眼蜂Trichogramma chilonis Ishii特异引物,同时采用文献中发表的松毛虫赤眼蜂Trichogramma dendrolimi Matsumura 和玉米螟赤眼蜂Trichogramma ostriniae Pang et Chen的特异引物以及赤眼蜂属Trichogramma 特异引物对赤眼蜂成虫和寄主卵样品进行了PCR特异扩增分析。结果表明,采用上述特异引物可从单头蜂稳定地扩增出明显的目的DNA条带,并且分子鉴定结果与形态学鉴定结果完全吻合。因此,采用上述3对特异引物可以实现对我国3种重要赤眼蜂种,即松毛虫赤眼蜂、螟黄赤眼蜂和玉米螟赤眼蜂的分子鉴定。     

Rapid development of resistance to diamide insecticides in the smaller tea tortrix,Adoxophyes honmai (Lepidoptera: Tortricidae), in the tea fields of Shizuoka Prefecture,Japan

We investigated the susceptibility of the smaller tea tortrix, Adoxophyes honmai Yasuda, to diamide insecticides in the Shimada-Yui tea fields in Shizuoka Prefecture, Japan, from 2006 to 2011. By 2011, the insects had developed significant resistance even to concentrations far above the registration concentrations of two diamides, flubendiamide and chlorantraniliprole. The lethal concentration 50 (LC₅₀) values of flubendiamide showed a rapid annual increase from 16.2 ppm in 2007 to 161 ppm in August 2011, exceeding the registration concentration of 100 ppm in 2010 and 2011. The LC₅₀ values of chlorantraniliprole increased sharply from 25.3 ppm in 2010 to 98.8 ppm in August 2011, exceeding the registration concentration of 50 ppm. The LC₅₀ values for flubendiamide and chlorantraniliprole at 10 days after treatment in insects collected in August 2011 were 105-fold and 77.2-fold higher, respectively, than those in a susceptible strain.     

Topological persistency found in aggregations of coastal sea skater,Halobates japonicus Esaki, 1924 (Hemiptera: Gerridae), based on genetic relationships amongst three aggregations in Ishigaki Island,Japan

Sea skaters, genus Halobates Eschscholtz, 1822, are the only marine insects living in mangrove beds and the tide pools of coral reefs, both of which provide dramatically variable habitats daily by virtue of tide-driven changes in surface level. Females of H. japonicus Esaki, 1924 were collected from three distinct aggregations in a single bay (24°27′5″N, 124°8′40″E) on 1–5 November 2006. Two aggregations were formed in respective tide pools of the coral reef and one was formed in the mangrove beds. Amplified fragment length polymorphism markers were used to detect the persistency of each aggregation at a mesoscale. The results suggested that H. japonicus repeatedly immigrated from outside the bay to establish a meta-population of several deme groups. Aggregations along the coastline had some persistency to the line itself and had little tendency to cross to the opposite shore, even when the distance was short.     

The utility of microsatellite DNA markers for the evaluation of area-wide integrated pest management using SIT for the fruit fly, Bactrocera dorsalis (Hendel), control programs in Thailand

The oriental fruit fly, Bactrocera dorsalis (Hendel), is a key pest that causes reduction of the crop yield within the international fruit market. Fruit flies have been suppressed by two Area-Wide Integrated Pest Management programs in Thailand using Sterile Insect Technique (AW-IPM-SIT) since the late 1980s and the early 2000s. The projects’ planning and evaluation usually rely on information from pest status, distribution, and fruit infestation. However, the collected data sometimes does not provide enough detail to answer management queries and public concerns, such as the long term sterilization efficacy of the released fruit fly, skepticism about insect migration or gene flow across the buffer zone, and the re-colonisation possibility of the fruit fly population within the core area. Established microsatellite DNA markers were used to generate population genetic data for the analysis of the fruit fly sampling from several control areas, and non-target areas, as well as the mass-rearing facility. The results suggested limited gene flow (m < 0.100) across the buffer zones between the flies in the control areas and flies captured outside. In addition, no genetic admixture was revealed from the mass-reared colony flies from the flies within the control area, which supports the effectiveness of SIT. The control pests were suppressed to low density and showed weak bottleneck footprints although they still acquired a high degree of genetic variation. Potential pest resurgence from fragmented micro-habitats in mixed fruit orchards rather than pest incursion across the buffer zone has been proposed. Therefore, a suitable pest control effort, such as the SIT program, should concentrate on the hidden refuges within the target area.     

Investigating species boundaries using DNA and morphology in the mite <Emphasis Type="Italic">Tyrophagus curvipenis</Emphasis> (Acari: Acaridae), an emerging invasive pest,with a molecular phylogeny of the genus <Emphasis Type="Italic">Tyrophagus</Emphasis>

Mites of the genus Tyrophagus (Acari: Acaridae) are among the most widespread and common mites, inhabiting diverse natural and anthropogenic habitats. Some species are pests of agricultural products and stored food and/or live in house dust, causing allergies to humans. We sequenced 1.2 kb of the mitochondrial COI gene for 38 individuals belonging to seven species of Tyrophagus, including T. curvipenis, T. putrescentiae, T. fanetzhangorum, T. longior, T. perniciosus, and T. cf. similis. Molecular phylogenetic analyses (1) recovered two major clades corresponding to the presence or absence of eyespots, and (2) separated all included morphological species. Tyrophagus curvipenis and T. putrescentiae had the lowest between-species genetic distances (range, mean?±?SD): 14.20–16.30, 15.17?±?0.40 (K2P). The highest within-species variation was found in T. putrescentiae 0.00–4.33, 1.78?±?1.44 (K2P). In this species, we recovered two distinct groups; however, no geographical or ecological dissimilarities were observed between them. Based on our analyses, we document important morphological differences between T. curvipenis and T. putrescentiae. For the first time, we record the occurrence of T. curvipenis in the New World and suggest that it may be an emerging pest as it is currently spreading in agricultural produce.