潜蝇钻道，蜾蠃挖之 陈华燕 蜾蠃蜂隶属于膜翅目（Hymenoptera）胡蜂总科（ Vespoidea ），原先是一个独立的科蜾蠃蜂科（Eumenidae），现在一般认为是胡蜂科（Vespidae）中的蜾蠃蜂亚科（Eumeninae），也是最大的亚科，种类繁多，目前全世界知3700余种，中国已知260余种（Tan et al. 2018） 。 胡蜂科昆虫有很多种类具有社会性，即筑巢群居，但蜾蠃蜂比较特立独行，都是单栖性。雌性营狩猎性寄生生活，即雌虫筑好巢后产卵，再捕食猎物放入巢内饲育后代。我国古人对蜾蠃的这种狩猎性寄生习性三千年前就有记载。最出名的莫过于《诗经》的记载，“螟蛉有子，蜾蠃负之”指的就是蜾蠃蜂把一些鳞翅目的幼虫捕回巢内饲育后代的现象。只不过《诗经》这句话描述的是，古人认为蜾蠃只有雄的，没有雌的，于是把螟蛉带回巢内当成自己的儿子抚养。据传南北朝时的医学家陶弘景（公元 456-536 ）不相信蜾蠃无子，实验观察以辩真伪。结果他找到一窝蜾蠃，发现雌雄都有。可见我国古人早在 1500 年前就对这类昆虫有科学的观察。其实衔螟蛉的蜾蠃是雌蜂，找到螟蛉后，先用腹部末端的毒针（特化成螯针的产卵器）刺一下，释放毒液麻痹螟蛉，然后衔回巢内封起来。蜾蠃先前产下的卵孵化成幼虫后，就可以寄生取食这些螟蛉了，也就是说螟蛉不是蜾蠃的义子，而是蜾蠃后代的食物。蜾蠃的毒液具有保鲜作用，因此可以保证螟蛉在巢内可以长时间作为后代的食物。 蜾蠃的猎物多为鳞翅目（ Lepidoptera ）的幼虫，也有鞘翅目（ Coleoptera ）和叶蜂（ sawfly ）的幼虫。有些种类只限于猎捕一个科的昆虫，但有些种类猎捕的寄主范围比较广，可达 1 ～ 2 个目的昆虫，只要猎物的个体大小适合都可猎捕。 前两个星期回湛江老家探亲，在老家屋后拍虫子的时候，看到几只蜾蠃在马缨丹叶上咬潜叶虫为害处的叶皮。一直以来，我拍蜾蠃要么是访花的，要么是筑巢的，我一开始以为这蜾蠃是要咬叶片去筑巢，抓拍了几张，放大后看，原来是要吃里面的虫子。后来来查了一下资料，马缨丹上的潜叶虫很有可能是马缨丹蛇潜蝇（ Ophiomyia lantanae ），一种原产美洲的潜蝇，主要潜食植物叶片造成隧道，可致使叶片枯死，早在 100 多年前就被澳洲引入用于防治马缨丹。 2015 年首次报道我国大陆有马缨丹蛇潜蝇的分布（ Shi et al. 2015 ）。中科院动物研究所的袁峰老师看了我的照片后，认为蜾蠃是 Labus 这个属的，后经荷兰膜翅目分类专家 Cornelis van Achterberg 博士确认并认为可能是 Labus clypeatus 这个种，一个中国新记录种。 图 1. 蜾蠃 Labus sp. 在马缨丹叶上咬潜叶虫为害处的叶皮。 图 2. 蜾蠃 Labus sp. 在马缨丹叶上咬潜叶虫为害处的叶皮。换个角度，可以看见叶皮已经被咬破。 图 3. 蜾蠃 Labus sp. 在马缨丹叶上咬潜叶虫为害处的叶皮。继续往下咬。 图 4. 蜾蠃 Labus sp. 在马缨丹叶上咬潜叶虫为害处的叶皮。换个地方咬。 图 5. 蜾蠃 Labus sp. 终于挖到潜叶蝇的幼虫（或蛹）了。 图 6. 可能是马缨丹蛇潜蝇的幼虫。 Reference: 何俊 华等 (2002). 浙江蜂 类 志 . 科学出版社 . Shi L, Jin C, Gao X (2015) First report of Ophiomyia lantanae (Froggatt) (Diptera: Agromyzidae) on the Chinese mainland, with a checklist of known species of Ophiomyia in China. Entomotaxonomia 37(1): 59-71. Tan J-L, Carpenter JM, van Achterberg C (2018) An illustrated key to the genera of Eumeninae from China, with a checklist of species (Hymenoptera, Vespidae). ZooKeys 740: 109–149. https://doi.org/10.3897/zookeys.740.22654
荤素通吃的茧蜂 对于熟悉膜翅目昆虫的人们来说，一提到茧蜂，第一印象就是，它们是寄生于别的节肢动物尤其是昆虫的寄生蜂。通俗点讲就是，它们是靠吃荤（寄主的肉体）长大的。当然，如果你对茧蜂这个庞大的类群（全世界已知近 2 万种）更熟悉点的话，你会知道有极少数的种类是素食主义者，即是靠吃植物长大的，如有些种类能够取食植物的种子 ，而有些种类的幼虫能够使植物长出虫瘿 —— 植物膨大的组织，幼虫就靠吃这些组织来完成发育 。致瘿的茧蜂很容易让人联想到它们是由那些寄生于致瘿昆虫如木虱的类群逐渐进化过来的，因为寄生于致瘿昆虫的茧蜂可能会由于虫瘿里的寄主昆虫数量不够多，不能提供足够的食物，从而改吃荤为吃素。虽然已发现有少数几种茧蜂能够寄生致瘿的木虱，但并没有证据支持这些种类能够取食虫瘿的植物组织的设想［ 5-6 ］。 最近发表于 PLOS ONE 的一篇文章报道了第一个荤素通吃的茧蜂新种［ 7 ］。这种名为 Bracon garugaphagae Ranjith Quicke 的 茧 蜂 产 自印度。 雌蜂并没有像其它寄生蜂一样把卵产在寄主木虱的身体上致其麻痹， 而是把 单 粒卵 产在 由木虱 Phacopteronlentiginosum Buckton 在 羽叶白 头树 Garuga pinnata Roxb. 产生的虫瘿里，幼虫孵化后才一口一个的取食木虱的若虫。吃完虫瘿里所有的木虱后，茧蜂的幼虫继续取食虫瘿的组织直到发育成熟才在虫瘿里作茧化蛹。下图摘自原文。 茧蜂 Bracon garugaphagae Ranjith Quicke 的生物学特性 A: 雌蜂在木虱产生的虫瘿上产卵； B ：茧蜂的卵； C ：茧蜂的幼虫； D ：虫瘿内的茧蜂的茧。（引自 http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0156997 ） References: deMacêdo MV, Monteiro RT. Seed predation by a braconid wasp, Allorhogas sp. (Hymenoptera). J New York Ent Soc. 1989; 97:359–362. Austin AD, Dangerfield PC. Biology of Mesostoa kerri Austin and Wharton(Insecta: Hymenoptera: Braconidae: Mesostoinae), an endemic Australian waspthat causes stem galls on Banksiamarginata Cav. Aust. J. Bot. 1998, 46: 559–569. Flores S, Nassar JM, Quicke DLJ.Reproductive phenology and pre-dispersal seed predation in Protium tovarense (Burseraceae), with description of the firstknown phytophagous “ Bracon ” species(Hymenoptera: Braconidae: Braconinae). J Nat Hist. 2005, 39: 3663–3685. Perioto NW, Lara RIR, Ferrerira CS,Fernandes DRR, Pedroso EDC, Volpe HXL et al. A new phytophagous Bracon Fabricius (Hymenoptera:Braconidae) associated with Protium ovatum (Burseraceae) fruits from Brazilian savannah. Zootaxa. 2011, 3000: 59–65. Li F, van Achterberg C, He J. Newspecies of the family Triozidae (Homoptera: Psylloidea) from China, and the first record of Psylloidea ashost of Braconidae (Hymenoptera). Zool Med Leiden. 2000 , 74 (21):359–366. ChadwickCE, Nikitin MI. Records of parasitism in the families Ichneumonidae, Braconidaeand Aulacidae. J Ent Soc Aus (NSW). 1976; 9: 28–38. Ranjith AP, Quicke DLJ, Saleem UKA,Butcher BA, Zaldívar-Riverón A, Nasser M (2016) Entomophytophagy ('SequentialPredatory, then Phytophagous Behaviour') in an Indian Braconid ‘Parasitoid’Wasp (Hymenoptera): Specialized Larval Morphology, Biology and Description of aNew Species. PLoS ONE 11(6): e0156997.
Diversity of Insect Pollinators Why insect pollinators? You may ask. And it was also the the question I asked myself when I began to think about writing a blog post for the workshop of Communicating Science via Photography. The reasons are obvious. First and foremost, here is the fact, at least one out of every three bites of food we eat today is thanks to insect pollinators. Secondly, you have heard enough from the news that our pollinators are declining. However, when we talk about pollinators, the first thing comes into our mind is honey bee. Although it is true that honey bee is the most common pollinator, there are many other bees and insects pollinating flowering plants. Therefore, this post aims to show the diversity of insect pollinators. What are the insect pollinators? Many important insect pollinators are in the following orders: Hymenoptera (bees and wasps), Diptera(flies), Lepidoptera (butterflies and moths), and Coleoptera (Beetles). 1. Managed bees such as honey bees (Figure 1) and bumble bees (Figure 2) are the most common insect pollinators. Figure 1 A honey bee foraging on goldenrod flowers. Scientists have just found out that climate change does affect insect pollinators. According to a Purdue University study, rising levels of atmospheric CO2 have reduced proteins in goldenrod pollen, a key late-season food source for North American bees (Ziska et al. 2016). Figure 2 Five bumblebees are clustering on these milkweed flowers. One of the ways that we can do to save bees or other insect pollinators is to plant insect-pollinator-friendly flowers and flowering herbs in our gardens and yards. 2. Wild bees. More than 4000 species of bees live in the United States and Canada and the majority of them are wild bees,including the following green sweat bee (Figure 3). Figure 3 A lovely green sweat bee is foraging on the flowers of garlic mustard. 3. Wasps. Adult solitary wasps usually feed on otheri nsects or spiders, but some of them such as species in the family Sphecidae(Figure 4) may use nectar and pollen for food and therefore pollinate flowers as a result of their feeding. Figure 4 This GreatGolden Digger is a fairly common species found in flower gardens. 4. Flies. The most abundant flower-visiting fliesare found in the family Syrphidae, flower flies (Figure 5). Figure 5 A flowerfly is feeding on nectar at wild flowers. 5. Butterflies and moths. Numerous butterflies(Figure 6) feed on nectar from flowers as adults. Figure 6 A Peck'sSkipper, Polites peckius , feed on nectar from a Red Clover flower. Many moth species (Figure 7) are also found visiting flowers as adults. Figure 7 A tigermoth resting on milkweed flowers. 6. Beetles. Beetles may pollinate as they move from flower to flower feeding pollen, nectar or flower parts. Some are even named as flowerbeetles such as the following flower longhorn beetle (Figure 8). Figure 8 A flower longhorn beetle is munching on pollen of milkweed flowers.
标签: 膜翅目
