Inventory of Host Plants and Parasitoids of the Fall Armyworm (FAW), Spodoptera frugiperda (JE Smith), in the Southern Agricultural Zone of Niger

The fall armyworm, Spodoptera frugiperda (JE Smith), is a polyphagous pest reported in sub-Saharan Africa since 2016 and has expanded rapidly in almost Africa. In Niger, Spodoptera frugiperda (JE Smith) is considered like a major pest of maize, to which it causes significant damage, in a context where proven control methods against this moth remain almost non-existent. The objective of the present study was to determine the economic importance of FAW through the damage caused to the different host plants and to identify the parasitoids of this caterpillar. The study was conducted in the southern agricultural zone of Niger, specifically in the regions of Dosso, Maradi, Tahoua and Zinder. FAW eggs and caterpillars were collected from six villages in each region and then incubated and reared in the entomology laboratory of INRAN in Maradi. The rate of infestation of the different crops by FAW was determined as well as the observation of the beneficiaries. The results obtained indicate the presence of FAW on millet with an attack rate varying from 45.7% to 68%, sorghum with 47.2% to 62.25% and sesame with 9.7%. This work also revealed an oophagous parasitoid, Telenomus remus with 138 ± 23 and larval parasitoids, Cotesia sp with 16 ± 1 maximum number of individuals emerged from the collected material. Also, it was identified the parasitoid Cotesia icipe with a rate of parasitism from 4.6% to 5.75%;the Charops ater whose rate of parasitism varies from 4.5% and 12.25% but for Chelonus insularis with 17.25% and Tachnidae with 53%. These very interesting results will constitute a basis for the development of biological control and a component of an agroecological management strategy of caterpillar.

Diversity, Host Plant Range and Distribution of Thrips spp. (Thysanoptera: Thripidae) in Three Vegetable Production Basins in Burkina Faso

Onion is the most important vegetable produced in Burkina Faso. It contributes to food and nutrition security and is a source of income for farmers. Thrips, which feed on the leaves of the plant, are the main insect pest of onion. The objective of this study was to access the diversity, the host range and the distribution of Thrips spp. in three main onion production areas in Burkina Faso. Three sites were chosen in each vegetable production basin, and plant species present were sampled and inspected to determine their thrips’ infestation status. Seventeen cultivated or wild plant species were attacked by thrips. The incidence of attacks was highest on zucchini plants followed by cucumber, eggplant, and onion, respectively. Six thrips species were recorded of which Thrips tabaci (Lindemman) represented more than 70% of the total. The average density of Thrips spp. per plant varied significantly between production basins and plant species. The highest average number of Thrips spp. per plant was recorded on zucchini (40.28 ± 10.28;17.43 ± 13.48 and 14.33 ± 7.11 respectively in the North, Hauts Bassins, and Central Plateau). This study provided basic information that can lead to further research and the development of control methods.

Large-scale interplant exchange of macromolecules between soybean and dodder under nutrient stresses

Parasitic plants and their hosts communicate through haustorial connections.Nutrient deficiency is a common stress for plants,yet little is known about whether and how host plants and parasites communicate during adaptation to such nutrient stresses.In this study,we used transcriptomics and proteomics to analyze how soybean(Glycine max)and its parasitizing dodder(Cuscuta australis)respond to nitrate and phosphate deficiency(-N and-P).After-N and-P treatment,the soybean and dodder plants exhibited substantial changes of transcriptome and proteome,although soybean plants showed very few transcriptional responses to-P and dodder did not show any transcriptional changes to either-N or-P.Importantly,large-scale interplant transport of mRNAs and proteins was detected.Although the mobile mRNAs only comprised at most 0.2%of the transcriptomes,the foreign mobile proteins could reach 6.8%of the total proteins,suggesting that proteins may be the major forms of interplant communications.Furthermore,the interplant mobility of macromolecules was specifically affected by the nutrient regimes and the transport of these macromolecules was very likely independently regulated.This study provides new insight into the communication between host plants and parasites under stress conditions.

EFFECT OF HOST PLANTS AND INOCULUM FORMS ON THE INOCULUM POTENTIAL OF ARBUSCULAR MYCORRHIZAL FUNGI

The effects of inoculum forms (single-spore, multi-spores, or colonized root pieces) and host plants (Nicotiana tabacum L., Sorghum sudanense (Piper) Stapf, and Trifolium repens L.) on the development and inoculum potential (IP) of the arbuscular mycorrhizal fungi (AMF) :Glo-mus macrocarpum Tul & Tul, donuis mosseae (Nicol & Gerd.) Gerdemann & Trappe, Glomus ver-siforme (Karsten) Berch, and Sclerocystis sinu/osa Gerdemann & Bakhi cultured in pots were investigated. The lag phase of treatment with 50 spores or 0.5 g (fresh weight) of colonized root pieces was 4 weeks, much shorter than that of the treatment with 1 spore (8 weeks); the value of IP (VIP) and percentage of root colonization (PRC) of the former were greater than those of the latter. Only on the early stages of colonization was there difference between the 50 spores and the 0.5 g (fresh weight) of colonized root piece inoculation treatments. The EP per plant inoculated with 0.5 g (fresh weight) of colonized root pieces of AMF was greater than that of the other two treatments except G. versiforme on Nicotiana tabacum, while the PRC of the plants inoculated with 50 spores and 0.5 g (fresh weight) of colonized root pieces of AMF was higher than that of the 1 spore inoculation after 10 weeks. Trie VIP of AMF on Trifolium repens was significantly higher than that on the other two hosts. The VIP of G. mosseae, G. versiforme, and S. sinuosa was respectively greater than that of G. macrocarpum. This suggested that different species of AMF produced different VIP of the inoculum . Nicotiana tabacum was much better than the other host plants which used to be inoculated with single spore, and to produce inocula of AMF.

Olfactory Responses of Tomicus yunnanensis to Different Non-host Plants

[ Objective ] With Cupressustorulosa, Cinnamomum camphora and Cyclobalanopsis Oerst as test materials, the paper studied the effects of different non- host plants on olfactory responses of Tomicus yunnanensis. [ Method ] The needles of Pinus yunnanensis were mixed with the leaves of Cupressustondosa, C. cam- phora and C. Oerst according to the ratios of 0 g ： 6 g, 1 g ： 5 g, 2 g ： 4 g, 3 g ： 3 g, 4 g ： 2 g, 5 g ： 1 g and 6 g ： 0 g, and the mixtures were put in the re- spanse arm of Y-tube olfactometer as odor source to observe the olfactory behavior of T. yunnanensis, the empty arm was set as control. [ Result ] When the needles of P. yunnanensis were mixed with the leaves of non-hest plants according to the ratio of 1 g ： 5 g and 2 g ： 4 g, they had less difference on attractive rate to T. yun- nanensis compared with complete P. yunnanensis needles in mixture （ratio： 6 g ： 0 g）, and the maximum difference was 14%. When the needles ofP. yunnanen- sis were mixed with non-host leaves according to the ratio of 1 g ： 5 g, 2 g ： 4 g, the attractive rate to T. yunnanensis decreased compared with complete P. yun- nanensis needles in mixture （ ratio： 6 g ： 0 g）, and the decrease value in maximum was 40%. [ Conclusion] When the ratio of non-host plants was relatively small in mixed leaves, non-host had less impact on olfactory responses of T. yunnanensis. As the proportion of non-hest leaves gradually increased, the attractive rate of leaf mixtures to T. yunnanensis was gradually small. The results could provide reference for determination of mixed ratio in construction of mixed forest and the de- velopment of botanical attractive and repellent of T. yunnanensis.

The Efficiency of Southern rice black-streaked dwarf virus Transmission by the Vector Sogatella furcifera to Different Host Plant Species

Southern rice black-streaked dwarf disease is a new rice disease that severely affects rice production in South China.To understand transmission capacity of the vector Sogatella furcifera to Southern rice black-streaked dwarf virus（SRBSDV） among different host plant species,potential host plants of SRBSDV collected from the diseased rice field and/or adjacent to the field in Hunan Province,China,were determined by RT-PCR,and the transmission rates of SRBSDV by S.furcifera among different host plant species were investigated.The results showed that host plants of SRBSDV in the rice fields were five of family Gramineae（Oryza sativa,Echinochloa crusgalli,Zea mays,Paspalum distichum,Alopecurus aequali） and two of family Cyperaceae（Juncellus serotinus and Cyperus difformis）.S.furcifera could not transmit SRBSDV between gramineous plants and cyperaceous plants,and could not transmit SRBSDV between the gramineous plants,J.serotinus and C.difformis as well.However,SRBSDV could be transmitted by S.furcifera within gramineous plants.S.furcifera could transmit SRBSDV between interspecies among three species plants（O.sativa,E.crusgalli and Z.mays）,and between P.distichum and A.aequali.At 15,20,25,30,and 35°C,both macropterous and brachypterous adult of S.furcifera could transmit SRBSDV from the plants（e.g.,E.crusgalli,Z.mays and O.sativa） infected with SRBSDV to rice seedlings.The transmission rates were first increased and then decreased with the increase of temperature.Macropterous adults transmitted SRBSDV from the viruliferous E.crusgalli,Z.may and rice plants to the healthy rice seedlings,and the infected rates of rice seedlings were 26.2,18.8 and 23.7% at 15°C,56.6,64.6 and 53.6% at 25°C,and was 11.2,10.2 and 7.3% at 35°C,respectively.Transmission capacity of brachypterous adults was significantly higher than that of macropterous adults at 15,20 and 25°C（P0.05）,while transmission capacity of brachypterous adults was relatively lower compared with that of macropterous ones at 35°C.These results offer evidence on the transmission of SRBSDV via the vector S.furcifer among different host plants,which can be helpful to control Southern rice black-streaked dwarf disease by the appropriate cultural measures in South China.

Effect of Host Plants on Development,Fecundity and Enzyme Activity of Spodoptera exigua (Hübner)(Lepidoptera:Noctuidae)

The beet armyworm,Spodoptera exigua （Lepidoptera：Noctuidae）,is an economically important pest of crops worldwide,attacking plants from over 20 families including trans-continental agricultural cotton,corn and citrus crops.In this study,performance and subsequent enzyme activity of beet armyworm reared on host plants from five families were investigated.Significant differences were found in development,fecundity and enzyme activity on different host plants.Survival rate was the highest （42.8%） on asparagus lettuce （Lactuca sativar var.asparagina） and the lowest （17.0%） on sweet pepper （Capsicum annuum）.Larval duration was the shortest on asparagus lettuce （12.0 d）,and was 43.4% longer on sweet peppers （21.2 d）.The activity of acetylcholine esterase （AChE） and carboxylesterase （CarE） in 3rd instar larvae,and soluble carbohydrate and crude protein contents in different host plants were determined.AChE activity was the highest in the larvae feeding on Chinese cabbage （Brassica rapa）,but declined by nearly 60% on maize （Zea mays） seedlings.The ratio of soluble carbohydrate content to crude protein content in host plants was found to have a positive effect on oviposition and a negative correlation with larval duration and life time （from larval to adult stages） of the insect.

Selectiveness of Cnaphalocrocis medinalis to Host Plants

A field experiment was conducted to study the selectiveness of Cnaphalocrocis medinalis Guenee （commonly known as the rice leaffolder or rice leafroller） towards five rice varieties （Yangfujing 8, Yangdao 6, Shanyou 136, Huaidao 9 and Nin.gjing 1） and three weed species （Echinochloa crusgalli, Leptochloa chinensis and Leersia hexandra）. The results showed that the rice varieties carried significantly higher numbers of C. medinalis moths and eggs than the weed species. Among the rice varieties, Yangfujing 8 was associated with a higher moth number. However, there was little difference in the number of C. medinalis eggs among the rice varieties. Additionally, a laboratory experiment was performed to investigate the olfactory response of female C. medinalis towards volatile compounds from different rice varieties, as well as its oviposition preference towards these rice varieties. The volatiles of Yangfujing 8, Yangdao 6 and Shanyou 136 attracted C. medinalis similarly to those of TN 1. In contrast, the volatiles of Huaidao 9 and Ningjing 1 clearly deterred C. medinalis. Nevertheless, C. medinalis did not exhibit clear oviposition preference towards any of the five tested rice varieties.

Inter-species mRNA transfer among green peach aphids,dodder parasites,and cucumber host plants

mRNAs are transported within a plant through phloem.Aphids are phloem feeders and dodders(Cuscuta spp.)are parasites which establish phloem connections with host plants.When aphids feed on dodders,whether there is trafficking of mRNAs among aphids,dodders,and host plants and if aphid feeding a匚fects the mRNA transfer between dodders and hosts are unclear.We constructed a green peach aphid(GPA,Myzus persicae)-dodder(Cuscuta austra/is)-cucumber(Cucumis sativus)tritrophic system by infesting GPAs on C.australis,which parasitized cucumber hosts.We found that GPA feeding activated defense-related phytohormonal and transcriptomic responses in both C.australis and cucumbers and large numbers of mRNAs were found to be transferred between C.australis and cucumbers and between C.australis and GPAs;importantly,GPA feeding on C.australis greatly altered inter-species mobile mRNA profiles.Furthermore,three cucumber mRNAs and three GPA mRNAs could be respectively detected in GPAs and cucumbers.Moreover,our statistical analysis indicated that mRNAs with high abundances and long transcript lengths are likely to be mobile.This study reveals the existence of inter-species and even inter-kingdom mRNA movement among insects,parasitic plants,and parasite hosts,and suggests complex regulation of mRNA trafficking.

Electrophysiological and Behavioral Responses of Adult Anoplophom glabripennis (Motschulsky) to Volatile Components of Host-Plant

Electrophysiological and behavioral responses of adult A. glabripennis (Motsch.) to volatiles from ashleaf maple (Acer negundo L.) were investigated to identify semiochemicals involved in host location. Measurable electroantennogram (BAG) responses were elicited to all compounds tested, the most effective antennal stimulants were trans-2-hexen-1-al,decyl aldehyde and trans-2-hexenl-ol.These profiles were similar between males and females. In Y-tube olfactometer bioassays, above three compounds with certain concentration, trans-2-hexen-l-al (1%), trans-2-hexen-l-ol (1%) and decyl aldehyde (10%), were significantly attractive to the adults in laboratory. The results show that either BAG or olfactory responding to a particular volatile compound are markedly influenced by the concentration.

Mutual Information Flow between Beneficial Microorganisms and the Roots of Host Plants Determined the Bio-Functions of Biofertilizers

Modern agriculture is facing new challenges in which ecological and molecular approaches are being integrated to achieve higher crop yields while minimizing negative impacts on the environment. The application of biofertilzers could meet this requirement. Biofertilizer is a natural organic fertilizer that helps to provide all the nutrients required by the plants and helps to increase the quality of the soil with a natural microorganism environment. This paper reviewed the types of biofertilzers, the biological basic of biofertilizers in plant growth promotion. This paper also assayed the bidirectional information exchange between plant-microbes in rhizoshpere and the signal pathway of plant growth- promoting rhizobacteria (PGPR) and plant growth-promoting fungi (PGPF) in the course of plant infection. At last, the challenges of the application and the promising future of biofertilizers were also discussed.

Effect of Pesticides on Growth of Rhizobia and Their Host Plants During Symbiosis

Effect of various pesticides (insecticides, fungicides and herbicides) has been studied on growth and efficiency of symbiotic properties of 3 fast growing Rhizobium sp. under green house conditions. The results revealed adverse effects on plant growth and nitrogen fixing capacity as measured by dry weight and total nitrogen content of plants infected with pesticide treated Rhizobium. Of the pesticides tested, herbicides were found to be more effective on the above parameters than the insecticides and fungicides.

Alternative Host Plants of Calidea panaethiopica (Hemiptera: Scutelleridae) and Aphtona whitfieldi (Coleoptera: Chrysomelidae), Insect Pests of Jatropha curcas, South Burkina Faso

Jatropha curcas is subject to the attacks of many insect pests, including Calidea panaethiopica Kirkaldy 1909 (Hemiptera: Scutelleridae) whose larvae and adults feed on flowers, fruit and seeds of the shrub resulting in quantitative and qualitative losses;the shrub is also attacked by Aphthona whitfieldi Bryan (Coleoptera: Chrysomelidae) which feeds on the leaves causing complete defoliation in severe attack. Despite their economic importance, very little is known about the alternative host plants of these insect pests. The study of the ecology of these species is a pre-requisite for the development of appropriate control methods. The identification of alternative host plants of C. panaethiopica and A. whitfieldi was conducted from June 3rd 2013 to November 30th 2014 in the Sissili province, South Burkina Faso. During that period, four J. curcas’ plantations of six locations in the province were prospected for alternative host plants of the two insect pests. In each plantation, observations were done across a diagonal up to 500 m away from the plantation. Fallows in the vicinity of the J. curcas plantations were particularly examined. Potential host plants of the two insect pests were collected and bred in the laboratory in Léo where they were used to feed the insect pests. Only Jatropha gossypiifolia, a cousin of J. curcas, was found to be a common alternative host plant of both insect pests.

Alternative Host Plants of <i>Calidea panaethiopica</i>(Hemiptera: Scutelleridae) and <i>Aphtona whitfieldi</i>(Coleoptera: Chrysomelidae), Insect Pests of <i>Jatropha curcas</i>, South Burkina Faso

Jatropha curcas is subject to the attacks of many insect pests, including Calidea panaethiopica Kirkaldy 1909 (Hemiptera: Scutelleridae) whose larvae and adults feed on flowers, fruit and seeds of the shrub resulting in quantitative and qualitative losses;the shrub is also attacked by Aphthona whitfieldi Bryan (Coleoptera: Chrysomelidae) which feeds on the leaves causing complete defoliation in severe attack. Despite their economic importance, very little is known about the alternative host plants of these insect pests. The study of the ecology of these species is a pre-requisite for the development of appropriate control methods. The identification of alternative host plants of C. panaethiopica and A. whitfieldi was conducted from June 3rd 2013 to November 30th 2014 in the Sissili province, South Burkina Faso. During that period, four J. curcas’ plantations of six locations in the province were prospected for alternative host plants of the two insect pests. In each plantation, observations were done across a diagonal up to 500 m away from the plantation. Fallows in the vicinity of the J. curcas plantations were particularly examined. Potential host plants of the two insect pests were collected and bred in the laboratory in Léo where they were used to feed the insect pests. Only Jatropha gossypiifolia, a cousin of J. curcas, was found to be a common alternative host plant of both insect pests.

寄主植物及猎物对杂食性天敌烟盲蝽若虫存活和发育的影响

杂食性昆虫烟盲蝽是多种害虫的重要捕食性天敌,它在猎物缺乏时可通过取食一些植物维持生存。因此,了解烟盲蝽在不同植物上的生物学特性以及有无猎物对其生物学特性的影响,是利用烟盲蝽创建储蓄植物系统开展害虫生物防治的基础。本研究通过室内离体叶片添加或不添加猎物烟粉虱、以及整株植物饲喂若虫的方法,测试了烟盲蝽在芝麻、香雪球和荞麦3种蜜源植物以及棉花和小白菜两种作物上的存活、发育及性比。结果表明,无猎物时,烟盲蝽若虫在芝麻和小白菜离体叶片上能发育至成虫,成虫获得率分别是85.2%和80.0%,若虫发育历期分别为15.0d和19.2d,但在荞麦、香雪球、棉花离体叶片和清水对照上分别只发育至4龄、3龄、3龄和2龄。添加猎物时,烟盲蝽若虫在5种植物离体叶片上都能发育至成虫,其中在芝麻上的若虫期最短,为11.8d,成虫获得率最高,为83.3%。烟盲蝽若虫在几种整株植物上的存活和发育与离体叶片上的结果相似,即只能在芝麻和小白菜上发育至成虫,成虫获得率分别为93.3%和66.7%。所有测试条件下饲养的烟盲蝽雌性比都在0.6左右,且雌、雄虫的若虫发育历期差异不显著。最后讨论了利用烟盲蝽这一重要杂食性天敌创建储蓄植物系统实施害虫生物防治的可行性。

非寄主植物精油对桔小实蝇的驱避效果研究

桔小实蝇Bactrocera dorsalis Hendel幼虫期隐蔽性的取食习性降低了化学防治的效果,而普遍存在的杀虫剂耐药性则加剧了这一问题。利用非寄主植物挥发物驱避害虫是替代化学防治、有效控制虫害的策略之一。为了筛选更有效的植物源产卵驱避剂,本研究选取23种非寄主植物精油作为候选材料,进行4轮试验,首先采用行为趋向反应试验,筛选出8种驱避率较高且选择反应率和驱避反应率差异极显著(P<0.01)的非寄主植物精油:绿花白千层、山鸡椒、广藿香、当归、茶树、茴香、薄荷、艾草;然后通过产卵驱避活性试验,筛选出4种驱避率高且处理组与对照组的产卵量差异极显著(P<0.01)的植物精油:绿花白千层、广藿香、当归、茶树。浓度梯度试验表明,浓度为5000μg/mL时,绿花白千层、广藿香、当归驱避率最高,浓度为3000μg/mL时,茶树精油驱避率最高;在最佳浓度下对桔小实蝇产卵驱避持效性分析,结果表明最佳浓度下4种精油处理过的果实,随着时间延长,桔小实蝇产卵孔和产卵量逐渐增加,驱避率逐渐降低,驱避产卵活性逐渐消失,前3 d降速较快,然后逐渐放缓。本研究通过行为趋向反应试验、产卵驱避活性试验、浓度梯度试验和驱避活性持效试验,从23种非寄主植物精油中,筛选到绿花白千层精油对桔小实蝇有较高的产卵驱避活性,通过剂型改良等措施有望开发成植物源驱避剂。

寄主对瓜实蝇老熟幼虫和蛹的低温耐受性的影响

为明确不同寄主饲养的瓜实蝇Bactrocera cucurbitae(Coquillett)幼虫与蛹的低温耐受性差异,选择西葫芦Cucurbita pepo、节瓜Benincasa hispida和黄瓜Cucumis sativus饲养多代的瓜实蝇老熟幼虫和不同日龄的蛹,分别测定其过冷却点、结冰点和在不同低温下的存活率,并进行比较分析。结果表明:取食不同寄主植物的瓜实蝇老熟幼虫过冷却点无显著差异,取食节瓜的老熟幼虫的结冰点[(-5.33±0.23)℃]最低,且与取食黄瓜的种群没有显著差异;取食节瓜的蛹的过冷却点与结冰点均最低,其中1日龄、3日龄和5日龄蛹的过冷却点和结冰点分别为(-19.28±0.30)℃和(-15.06±0.34)℃,(-20.97±0.40)℃和(-17.33±0.39)℃,(-20.08±0.46)℃和(-16.39±0.46)℃。取食节瓜和黄瓜的老熟幼虫在3、6℃和9℃下暴露1 d,其存活率均显著高于取食西葫芦的老熟幼虫;节瓜种群的1日龄蛹在3℃和9℃下暴露1 d时,其存活率都显著高于黄瓜和西葫芦种群的1日龄蛹的存活率。寄主植物可影响瓜实蝇的过冷却点、结冰点及低温存活能力,与其他寄主种群相比,瓜实蝇节瓜种群老熟幼虫和蛹对低温的适应能力更强。

草地贪夜蛾对7种寄主植物的选择性和适应性

【目的】探究草地贪夜蛾(Spodoptera frugiperda Smith)对不同寄主植物的选择性和适应性,为草地贪夜蛾的发生动态、监测预警和综合防治提供参考。【方法】选取玉米(Zea mays)、小麦(Triticum aestivum)、马铃薯(Solanum tuberosum)、苜蓿(Medicago sativa)、芹菜(Apium graveliens)、甘蓝(Brassica oleracea)和藜(Chenopodium album)7种常见寄主植物,采用笼罩试验和叶碟法研究草地贪夜蛾雌成虫的产卵选择性以及各龄期幼虫的取食选择性,记录草地贪夜蛾各龄期幼虫取食7种寄主植物后的发育历期、幼虫存活率、预蛹和蛹存活率、成虫羽化率、蛹质量、蛹长、蛹宽、成虫翅展和体长等指标,评估草地贪夜蛾对7种寄主植物的适应性。【结果】草地贪夜蛾雌成虫最偏好产卵在玉米叶片上,其次为小麦,也会产少量卵于甘蓝,但未见在苜蓿、马铃薯、芹菜和藜上产卵。草地贪夜蛾1~3龄幼虫最偏好取食苜蓿,其次为玉米和藜;4~6龄幼虫最偏好取食玉米,其次为苜蓿;各龄期幼虫均不偏好取食芹菜和马铃薯。草地贪夜蛾对7种寄主植物的适应性结果显示,幼虫取食7种寄主植物后均能正常生长发育并完成一个世代,且幼虫取食玉米后各虫期的发育历期最短,其次为取食苜蓿的幼虫,取食甘蓝后的幼虫生长发育最缓慢;幼虫取食玉米、苜蓿、小麦和藜后的存活率、预蛹和蛹存活率、成虫羽化率、蛹和成虫个体大小等均较高,取食马铃薯、甘蓝和芹菜的草地贪夜蛾上述各项指标数值均较低。【结论】草地贪夜蛾雌成虫最偏好产卵于玉米叶片,低龄幼虫最偏好取食苜蓿,且取食苜蓿后的幼虫存活率高于取食玉米的幼虫,建议在做好玉米田草地贪夜蛾监测的同时,应加强对苜蓿上草地贪夜蛾为害风险的监测。

不同寄主对白茨粗角萤叶甲生长发育和繁殖的影响

为探究不同寄主植物对温性荒漠草原主要害虫白茨粗角萤叶甲Diorhabda rybakowi的产卵选择、生长发育及繁殖的影响,本研究以唐古特白刺、泡泡刺和大果白刺为试验材料,在实验室养虫箱恒温(27℃)条件下,以3种白刺饲养白茨粗角萤叶甲,观察记录白茨粗角萤叶甲各虫态的发育历期、存活率、羽化率、成虫寿命等生物学特性,以及白茨粗角萤叶甲成虫的产卵偏好选择;同时测定了3种白刺叶片中的可溶性糖、淀粉和游离氨基酸含量。结果如下:白茨粗角萤叶甲成虫在3种白刺上的产卵量及着卵率由高到低均为唐古特白刺,泡泡刺,大果白刺。取食3种白刺植物后,白茨粗角萤叶甲均能正常完成各阶段的生长发育;饲喂唐古特白刺的白茨粗角萤叶甲幼虫发育历期最短(13.50d),饲喂大果白刺的幼虫发育历期最长(16.70 d),同时,饲喂唐古特白刺的幼虫存活率最高,为97.78%,大果白刺上幼虫的存活率仅为10.54%。相应地,饲喂唐古特白刺后羽化成虫的寿命和繁殖力最高,大果白刺上成虫寿命和繁殖力最低。相关性分析表明,可溶性糖、淀粉和游离氨基酸含量与白茨粗角萤叶甲蛹期、成虫寿命、孵化率和羽化率无显著相关性,而幼虫总历期与各营养含量呈极显著负相关,与糖氮比呈极显著正相关;产卵量和幼虫总存活率与各营养物质的含量均呈极显著正相关,与糖氮比呈极显著负相关。唐古特白刺是白茨粗角萤叶甲的最适寄主植物,其次为泡泡刺。

不同寄主植物对桫椤叶蜂的生长发育及其肠道细菌群落的影响

为明确桫椤叶蜂Rhoptroceros cyatheae幼虫取食桫椤Alsophila spinulosa及小黑桫椤Gymnosphaera metteniana var.subglabra两种寄主植物后肠道菌群的结构组成和多样性,及取食两种寄主植物上的平均发育历期,利用Illumina HiSeq技术对取食两种寄主植物后的桫椤叶蜂幼虫肠道细菌的16S rDNA的V3~V4区域进行测序与分析,并记录在寄主植物上的平均发育历期。结果显示:(1)取食小黑桫椤的叶蜂卵历期、老熟幼虫期、蛹期(4.07±0.80 d、9.15±1.36 d和3.82±1.11 d)相比取食桫椤的(4.57±0.65 d、10.75±1.73 d和4.73±0.86 d)显著缩短,成虫寿命无显著影响;(2)取食桫椤的幼虫肠道注释到细菌4门6纲17目26科37属,取食小黑桫椤的桫椤叶蜂幼虫肠道注释到细菌12门17纲32目44科58属;其中,变形菌门Proteobacteria(83.68%±3.74%、81.18%±0.75%)是两组肠道的优势菌门;肠杆菌属Enterobacter(61.98%±10.64%、30.25%±1.75%)为两组的优势菌属。α多样性分析表明取食小黑桫椤的叶蜂幼虫肠道微生物群落多样性略高于取食桫椤的叶蜂幼虫,β多样性分析结果显示,取食小黑桫椤的叶蜂幼虫肠道微生物群落更稳定。KEGG功能预测分析显示取食桫椤和小黑桫椤的叶蜂肠道细菌群落功能无差异,肠道细菌主要参与宿主的营养代谢。本研究为进一步探讨影响桫椤叶蜂肠道细菌变化的因素,以及后续研究肠道细菌与寄主植物之间的互作提供参考。