外来种刺槐叶瘿蚊的重要寄生性天敌——刺槐叶瘿蚊广腹细蜂在中国的地理分布

刺槐叶瘿蚊广腹细蜂Platygaster robiniae Buhl and Duso(膜翅目:细蜂科)是我国外来有害生物刺槐叶瘿蚊Obolodiplosis robiniae(Haldeman)(双翅目:瘿蚊科)十分重要的寄生性天敌,为卵-幼虫跨期寄生蜂,专化性强,在自然抑制害虫虫口密度中起着非常重要的作用。为摸清刺槐叶瘿蚊广腹细蜂在我国的地理分布,探讨其与刺槐叶瘿蚊的相互关系,本文根据寄主刺槐叶瘿蚊在我国的分布范围,采用踏查的方法,对全国17个省、市、自治区的29个地区进行了调查。结果显示,刺槐叶瘿蚊广腹细蜂在其寄主分布区都有分布,分布范围在26°35.451′-43°53.482′N,103°51.816′-125°15.969′E,海拔4-1 097 m。     

我国新发现一种重要外来入侵害虫——刺槐叶瘿蚊

在我国首次发现了一种新的重要外来入侵害虫——刺槐叶瘿蚊Obolodiplosis robiniae (Haldemann)。该害虫原产北美洲东部,危害刺槐叶片。其危害特征十分明显：一般是3～8头幼虫群集危害,在刺槐叶片背面沿叶缘形成纵向卷曲的虫瘿,隐藏其中取食。在我国河北省秦皇岛市、辽宁省一些地区刺槐树的受害率近100％,严重影响刺槐的健康生长,进而引起次期性害虫的发生和危害,造成刺槐死亡。因此,该害虫对我国大面积栽培的刺槐林的生态、经济以及社会效益的发挥造成重大威胁。必须提高警惕,加强检疫,防止其扩散蔓延,并开展防治研究。     

刺槐叶瘿蚊在中国的危险性评估

采用CLIMEX模型预测分析了刺槐叶瘿蚊Obolodiplosis robiniae(Haldemann)在中国的潜在地理分布,并参照我国有害生物危险性定量分析方法,对刺槐叶瘿蚊在中国的危险性作出综合评价.结果表明:刺槐叶瘿蚊在中国潜在的分布区范围是98 30°～132.03°E,24.23°～47.41°N.最宜适生区(EI ≥ 15)包括华北、华中、华南及云南大部分地区;适生区(5 ≤ EI＜15):包括辽宁和河北中南部,山西及陕西南部,四川、甘肃东南部分地区;半适生区(0 ＜ EI ＜ 5):包括黑龙江、吉林、四川大部分地区及西藏、甘肃、宁夏部分地区;其余各地的EI值均小于等于0,属于非适生区.预测其在中国的风险值为2.26,根据国际上风险值分级标准,属于高度危险生物.据此提出了针对性的风险管理措施.     

刺槐叶瘿蚊成虫行为学特征及性诱效果的研究

本文在室内条件下研究了刺槐叶瘿蚊Obolodiplosis rohiniae(Haldemann)成虫羽化、交尾、产卵行为的时间动态节律以及雌蚊性诱效果.结果表明:雌虫5:00-6:00为羽化高峰期,雄虫1:00-2:00为羽化高峰期,雌虫羽化高峰期期迟于雄虫4 h左右.雌蚊羽化后20min左右即外伸产卵器吸引雄蚊交配...     

外来致瘿害虫——玫瑰犁瘿蜂在中国首次发现

玫瑰犁瘿蜂Diplolepis rosae(L.)原产于北美地区,首次在中国发现。该外来入侵种在甘肃地区危害苦水玫瑰(Rosa serrata×R.Rugosa),造成巨大经济损失。本文主要介绍了该种幼期、成虫及其虫瘿的形态特征、编制该种近缘种的检索表。同时,发现该种的天敌之一——玫瑰瘿长尾小蜂Torymus bedeguaris(L.),并对其寄生率进行了调查,结果表明该长尾小蜂可有效控制种群数量的增长。     

日本细毛环腹瘿蜂生物学特性研究

日本细毛环腹瘿蜂为斑翅果蝇幼虫优势寄生性天敌之一,对斑翅果蝇具有较大的控制潜能.本研究以斑翅果蝇为寄主,在实验室条件下,通过饲养与观察,研究了日本细毛环腹瘿蜂的寿命、行为节律、寄主选择、生长发育及繁殖.结果显示:不同营养条件下,寄生蜂寿命长短依次为20％蜂蜜水＞10％蜂蜜水＞清水＞对照.寄生蜂羽化期为8d,第4天为羽化...     

垂叶榕果内寄生瘿蚊的发生规律

在云南西双版纳热带地区,一种还未被描述属和种的瘿蚊寄生于垂叶榕果内的雌花子房里,并膨大形成虫瘿,靠取食花胚组织完成发育.通过2010年定时定点的系统观察和研究瘿蚊的发生规律,结果发现:该种瘿蚊在垂叶榕上发生频率较高,抽样的18批果有17批被瘿蚊寄生,其中有13批果的寄生比率超过了60％,部分甚至达到100％.瘿蚊寄生雌花的平均比率不超过6％,平均每个榕果内有瘿蚊1～40只不等.瘿蚊寄生不仅降低了垂叶榕的种子数,还致命性地影响着传粉榕小蜂的繁殖.在对瘿蚊的羽化、交配行为及其成虫的活动规律观察中,结果显示:寄生在一个榕果里瘿蚊需要5～7d才能羽化完,其羽化高峰期出现在第2～3天;一天内羽化的高峰出现在上午8:00-10:00及晚上20:00-0:00;而羽化后瘿蚊活动高峰期出现在上午8:00-11:00.雄蚊会帮助雌蚊离开榕果并优先获得交配权,雌蚊交配后飞离繁殖自身的榕树,去寻找适合产卵的榕果繁殖后代,雄蚊不离开羽化树,而死在繁殖自身的榕树附近.这些结果为深入研究瘿蚊的防治技术提供了科学依据.     

杀虫剂对湿地松粉蚧种群及其天敌的影响

湿地松粉蚧是于1988年传入我国广东省的一种重要林业外来入侵害虫。现在该害虫在我国的分布面积为35.52万公顷,严重影响着我国南方松林的生长健康。该害虫在其原产地美国南方并不造成大的危害,也不是一种主要害虫。只有当大量应用杀虫剂防治其它害虫时,由于杀死了其天敌,湿地松粉蚧种群才会明显增长。为控制这一外来入侵害虫,中美两国于1995年开展了从美国引进天敌防治广东省湿地松粉蚧的林业合作项目。本文报道了1996～1997年间在美国南方三个种子园使用杀虫剂防治球果种实害虫时,杀虫剂对湿地松粉蚧种群及其两种主要天敌有明显的影响,这也间接地说明了寄生性天敌对湿地松粉蚧在自然条件下的控制作用。相关分析显示湿地松粉蚧种群数量与其天敌是密切相关的,但杀虫剂可以打破这种平衡。这一方面说明从美国引进天敌防治湿地松粉蚧是可行的,另一方面也显示在美国采集湿地松粉蚧天敌应在使用过杀虫剂后的林分中。     

元宝枫籽象的重要天敌昆虫——元宝枫刺胫广肩小蜂线粒体全基因组的测定与分析

【目的】元宝枫刺胫广肩小蜂Eurytoma acutibialis Yang, Liu et Cao是我国元宝枫种实Acer truncatum的主要害虫元宝枫籽象Bradybatus sp.的寄生蜂,是调查元宝枫籽象时发现的一个新种,在控制元宝枫籽象上可发挥重要作用。为进一步了解该新寄生蜂,测定和分析元宝枫刺胫广肩小蜂的线粒体全基因组序列,从而为膜翅目(Hymenoptera)小蜂总科(Chalcidoidea)广肩小蜂科(Eurytomidae)昆虫系统分类和发育系统关系等研究提供分子生物学证据。【方法】采用Illumina HiSeq^TM4000测序平台测定元宝枫刺胫广肩小蜂线粒体全基因组序列,并进行拼接、注释和分析。基于膜翅目小蜂总科40种昆虫线粒体的13个蛋白质编码基因(protein-coding genes, PCGs)的核苷酸序列,应用贝叶斯法(Bayesian inference, BI)和最大似然法(maximum likelihood, ML)构建系统发育树,分析元宝枫刺胫广肩小蜂与小蜂总科其他昆虫的系统发育关系。【结果】元宝枫刺胫广肩小蜂线...     

Female reproductive biology of Platygaster diplosisae (Hymenoptera: Platygastridae) and Aprostocetus procerae (Hymenoptera: Eulophidae), two parasitoids associated with the African Rice Gall Midge, Orseolia oryzivora (Diptera: Cecidomyiidae)

We investigated the female reproductive system of Platygaster diplosisae (Hymenoptera: Platygastridae) and Aprostocetus procerae (= Tetrastichus pachydiplosisae) (Hymenoptera: Eulophidae), two parasitoids associated with the African rice gall midge, Orseolia oryzivora (Diptera: Cecidomyiidae). Both optical and electron microscopy were used. The female reproductive system of P. diplosisae includes two large ovaries of the meristic polytrophic‐type, each composed of several tens of ovarioles. The system includes also a venomous gland that extends to a common oviduct. This gland had a filiform secretory portion, in which the epithelium was thin and surrounded a common evacuation canal. The secretory cells secrete into a large reservoir. Parasitism due to P. diplosisae is gregarious. The female reproductive system of A. procerae includes two ovaries of the meristic polytrophic‐type, and each ovary has a few ovarioles. Each ovariole includes one or two oocytes, which can be seen in the vitellarium. Two accessory glands, which extend to the oviduct, are also visible. The secretory epithelium of the accessory gland is made up of a dense network of secretory cells surrounded by muscle fibers. Females of A. procerae pierce the tissues of the gall and probably deposit one egg on or close to the pupa of the midge. Aprostocetus procerae is a solitary parasitoid of the midge. The two parasitoids exploit the same host at different developmental stages. These findings improve our knowledge of the reproductive biology of these two parasitoids associated with the African rice gall midge, an important pest in Africa.     

Differential thermal biology may explain the coexistence of Platygaster matsutama and Inostemma seoulis (Hymenoptera: Platygastridae) attacking Thecodiplosis japonensis (Diptera: Cecidomyiidae)

Two dominant parasitoids, Platygaster matsutama Yoshida and Inostemma seoulis Ko, often coexist in the host-parasitoid community of the pine needle gall midge, Thecodiplosis japonensis Uchida et Inouye. Subtle differences in parasitoid phenology appear to play a key role in reducing interspecific competition, but the specific thermal conditions for development of each species have not been defined. We examined the thermal biology of two sympatric parasitoids during postdiapause development at seven constant temperatures (12, 15, 18, 21, 24, 27, and 30 °C) to determine species-specific developmental parameters. The lower developmental threshold was estimated to be 4.2 °C and 8.4 °C, and the thermal constant was 741.2 and 946.1 degree days (DD) for P. matsutama and I. seoulis, respectively, using the linear model. The nonlinear model determined that the optimal temperature was 24.8 and 26.5 °C for P. matsutama and I. seoulis, respectively, but with an upper threshold temperature (30 °C) that was the same for both species. The development rate of P. matsutama was higher than that of I. seoulis over the entire thermal range, and the difference was highest at 21.5 °C. Despite the lower developmental rate, I. seoulis was more heat tolerant and its optimal temperature was closer to that of host insect than those of P. matsutama. The results showed clear differences in thermal biology between P. matsutama and I. seoulis. Potential implications are discussed with respect to coexistence of two parasitoids on a single host and biological control of T. japonensis.     

A new species of Aprostocetus Westwood (Hymenoptera: Eulophidae), parasitizing mango leaf gall midge (Diptera: Cecidomyiidae), from India

A new species of Aprostocetus doonensis Singh sp. nov. is described from northern India. The new species is a parasitoid of mango leaf gall midge, Procontarinia mangiferae (Felt) (Diptera: Cecidomyiidae). Some observations on biology and parasitization rate are also given.     

Host Location and Ovipositional Behavior of Platygaster demades Walker (Hymenoptera: Platygastridae), an Egg Parasitoid of Apple and Pear Leaf Curling Midges

The foraging responses of 1–2-day-old naïve female Platygaster demades to odors of apple and pear foliage and host insect eggs were measured. The host origin of P. demades had no effect on the parasitoids’ longevity, host preference, or foraging behavior. Four distinct behaviors related to oviposition were identified. In choice experiments, more female parasitoids responded to apple foliage with no midge eggs than to midge eggs alone. In a Y-tube olfactometer, parasitoids preferred the plant cues to clean air, and responded equally to both apple and pear odors. The results indicate that P. demades utilizes plant cues to locate the habitat of its host and then searches for host eggs to parasitize.     

Phenological dynamics of Dasineura mali (Diptera: Cecidomyiidae) and its parasitoid Platygaster demades (Hymenoptera: Platygasteridae) in apple orchards

The midge Dasineura mali Kieffer (Diptera: Cecidomyiidae) is an important pest of apple (Malus domestica Borkh.) and a potential fresh fruit contaminant, causing quarantine concerns. The phenological dynamics of D. mali and its egg parasitoid Platygaster demades Walker (Hymenoptera: Platygasteridae) were studied in the field in Palmerston North, New Zealand, for 2 yr. Both shoot infestation rate by D. mali and D. mali density per shoot sharply increased in the second generation, reaching approximately 65% and 100-200 eggs, respectively. However, although the infestation rate in the third generation remained as high as in the second generation, the pest density per shoot significantly decreased to 40-60 eggs in the third generation. In the fourth generation, both infestation rate and pest density per shoot decreased to approximately 30% and 10 eggs. Due to the simultaneous decline of the apple shoot number and D. mali density in the third and fourth D. mali generations, the absolute number of D. mali in the orchard also has declined proportionally during the same period. The parasitism and superparasitism rates significantly increased as the season progressed, from 45 to 55 and 37% in the first generation to 87 and 82% in the fourth generation, respectively. Our results suggest that P. demades contributes to the continuous decline of D. mali numbers in the field; it is a good searcher, particularly when its hosts become increasingly scarcer over the season, and it avoids overshooting the host population later in the season by increasing superparasitism. The frequency of P. demades aestivation increases from late spring to midsummer and then decreases during the late summer and early autumn. Although the emergence of P. demades was approximately 2 to 3 wk behind that of D. mali in each generation, the increasing parasitism rates from the first to the fourth generations indicate that P. demades is synchronized with D. mali in the field.     

First report of Culicoides boyi (Diptera: Ceratopogonidae) in France

Culicoides boyi Nielsen, Kristensen & Pape 2015 (Diptera: Ceratopogonidae), described in Denmark in 2015, is reported in France. This species is closely related to Culicoides pulicaris (Linnaeus 1758) and can only be distinguished from this species by a subtle variation in spot wing pattern and by calculation of maxillary palpal ratio.