盗蜜对角蒿传粉者行为和生殖成功的影响

一些研究显示盗蜜对自交植物的结实和结籽没有显著影响。然而, 对于既有传粉者为其传粉实现异交又能通过自交实现生殖保障的兼性自交植物来说, 盗蜜对其生殖的影响还知之甚少。由于兼性自交植物可以自交, 盗蜜对其总体结实可能不会有显著影响, 但可能会通过影响传粉者行为而影响传粉者介导的结实。为了验证这一假说, 本研究以兼性自交的一年生角蒿(Invarvillea sinensis var. sinensis)为研究材料, 通过野外调查和控制实验, 探讨了盗蜜对传粉者介导的结实(传粉者行为)和总体结实率的影响。结果表明: 角蒿的盗蜜者和主要传粉者相同, 均为密林熊蜂(Bombus patagiatus)。熊蜂盗蜜频率平均为20.24% (范围为0-51.43%)。盗蜜对角蒿总体结实率、每果结籽数和每果种子重量没有显著影响。然而, 被盗蜜花的柱头闭合比率显著高于未被盗蜜花, 说明盗蜜影响传粉者的访花行为和传粉者介导的结实率。另外, 被盗蜜花的高度显著高于未被盗蜜花, 说明盗蜜者倾向于从较大较高的花上盗蜜。这些结果为全面认识盗蜜对植物生殖的影响提供了新的信息。     

益智传粉生物学的研究

 益智（Alpinia oxyphylla）的花期从2月底至4月下旬;单株花期（花序）约为16～26 d,通常为23～26 d;单花花期一般为1 d。正常情况下,益智和其它山姜属植物一样,具有花柱卷曲性促进异花授粉的机制,表现出两种类型：花柱上举型和花柱下垂型,其花柱卷曲运动的节律与其它已报道的山姜属植物基本一致。但观察发现,当遭遇低温天气时(日最高气温<18℃),单花花期延长为2 d,无论是上举型个体还是下垂型个体,均只表现出一种花型——下垂型：上午开花时花柱弯向上,柱头位于已开裂散发出花粉的花药上方,直到第二天上午6∶30～11∶00间,花柱才陆续地慢慢向下运动,柱头下降至与花药等高或位于花药下方。益智的主要传粉昆虫是蜜蜂（Apidae sp.）、木蜂（Xylocopa sp.）,绝大多数的访花者的访花目的是吸蜜。益智的花蜜分泌量（8.37～15.79 μl）和花蜜含糖量（30.12%～32.83%）较高,花蜜是益智作为传粉者访花的最主要的报酬。实验结果还表明,益智花部中唇瓣对昆虫访花有显著的招引作用;益智的花蜜对蜜蜂的访花频率有显著的影响,对木蜂有一定的招引作用,但并不显著。而花粉（花药）则对昆虫的访花频率影响不大。人工授粉实验结果表明益智存在自交亲和性,无论是上举型或下垂型个体自交和异交均有较高的结实率;人工自交和异交的结实率在上举型植株中存在较大的差异,而在下垂型个体中则差异不明显;去雄套袋、去柱头套袋和完全套袋不授粉等处理均不结实,表明益智不存在无融合生殖现象和自动自花授粉现象。益智的繁育系统是异花授粉交配系统。     

毛乌素沙地固沙植物披针叶黄华主要传粉昆虫及其访花行为

披针叶黄华(Thermopsis lanceolata)是我国西部地区早春重要野生蜜源植物,也是一种重要的固沙植物,然而对其繁殖特性的研究甚少.本文在系统调查披针叶黄华的访花昆虫基础上,确定其主要传粉昆虫种类、访花行为、传粉过程以及日活动规律,以期揭示主要访花者行为对其有性繁殖的影响.作者在内蒙古毛乌素沙地设置1个10m×10 m的样方,于2010和2011年在披针叶黄华盛花期,采用目测、拍照和摄像等方式对传粉昆虫进行观测,记录样方内主要访花昆虫种类、数量、访花行为及日活动规律.研究表明,大和切叶蜂(Megachile japonica)和戎拟孔蜂(Hoplitis princeps)是披针叶黄华的主要传粉者,但两种昆虫的访花频率存在显著差异;晴天时,大和切叶蜂在19:00-13:00和16:00-18:00出现两个活动高峰,而戎拟孔蜂只在11:30-16:30出现1个活动高峰,两种蜂的访花活动高峰期存在互补关系.大和切叶蜂访花同时具有盗蜜行为,但其盗蜜行为对披针叶黄华的结籽率没有显著影响.根据种群数量、访花频率综合判断,大和切叶蜂是披针叶黄华优势传粉蜂.     

大叶铁线莲访花昆虫调查及盗蜜昆虫行为研究

大叶铁线莲Clematis heracleifolia DC. 的花朵大多下垂,需要传粉昆虫为其传粉,目前尚无关于其访花昆虫研究的报道。 通过2年的野外观察研究,共观察到27种昆虫访问大叶铁线莲。 发现有盗蜜行为的昆虫7种, 其中1种同时具有初级盗蜜和次级盗蜜行为,2种具有初级盗蜜行为,4种具有次级盗蜜行为;黄胸木蜂Xylocopa appendiculata Smith是主要的盗蜜昆虫,其盗蜜行为影响了其它昆虫的访花行为,对大叶铁线莲的传粉造成一定的影响。 在其余20种访花昆虫中,双带弄蝶Lobocla bifasciata (Bremer et Grey)、贡尺蛾Gonodontis aurata Prout、熊蜂Bombus sp.和姬蜂虻Systropus sp.是优势种; 而小青花金龟Oxycetonia jucunda Faldermann和日本条螽Ducetia japonica (Thunberg)访花频率最低,且访花目的只是取食花朵。 通过对大叶铁线莲访花昆虫的调查和盗蜜昆虫行为的研究,为大叶铁线莲的传粉生物学和保护提供参考依据。     

大和切叶蜂对其蜜源植物披针叶黄华的盗蜜行为

【目的】调查和观测内蒙古毛乌素沙地大和切叶蜂Megachile (Xanthosaurus) japonica Alfken对其蜜源植物披针叶黄华Thermopsis lupinoides (L.)的盗蜜行为。【方法】在披针叶黄华花期内, 设置样方观测披针叶黄华的主要访花昆虫。采用目测, 拍照等方法对大和切叶蜂盗蜜行为进行观测, 记录和统计花被盗蜜后留下的盗蜜孔的数量和在花上的位置。【结果】大和切叶蜂在披针叶黄华传粉蜂中数量上占有绝对的优势。作为初级盗蜜者时, 用上颚在花基部切割出一个纵向裂口, 将口器伸入孔内吸取花蜜。作为次级盗蜜者时, 利用已有的孔洞来吸蜜。在盗蜜时没有表现出寻找已经存在的盗蜜孔来吸蜜的现象, 同时其个体在盗蜜时表现出“偏好”花基部一侧的行为。在13个样地, 已开放花朵被盗蜜率最低为95.4%, 最高达到100%, 而未开放花朵的被盗蜜率最高则达到64.7%。【结论】在毛乌素沙地大和切叶蜂既是披针叶黄华的主要传粉者, 也是其初级盗蜜者和次级盗蜜者。     

洛阳地区黄胸木蜂访花植物种类及访花行为

【目的】明确黄胸木蜂Xylocopa appendiculata的访花植物种类和访花行为, 为进一步开发和利用木蜂资源奠定基础。【方法】 2009-2011年连续3年, 在洛阳地区黄胸木蜂的活动期3-10月, 采用目测、 拍照等方法记录其访花植物及访花行为, 记录和统计访花植物的生物学特征; 测量访花植物种类被盗蜜后盗蜜口的大小。【结果】在洛阳地区黄胸木蜂访花植物种类为27科52种, 主要的访花植物有25种。采访的植物种类中, 忍冬科和豆科植物最多, 分别为9种和8种, 占采访植物种类的17.31%和15.38%; 其中黄胸木蜂盗蜜的植物有16种, 占其采访植物种类的30.77%。在采访的植物种类中, 黄胸木蜂喜欢采访中等花型、 两侧对称的紫色、 黄色和白色花。在不同植物上, 黄胸木蜂的盗蜜口大小和访花频率不同, 黄胸木蜂在臭牡丹上的盗蜜口最大, 为9.43±1.91 mm, 蝟实上的盗蜜口最小, 为3.46±0.98 mm; 在紫薇上的访花速度最快, 访花频率为25.71±2.36朵/min; 在蜀葵上的单花停留时间和访花间隔时间均最长, 单花停留时间5.89±3.34 s, 访花间隔时间为2.63±2.04 s。【结论】在洛阳地区黄胸木蜂访花植物种类多、 访花时间长。对于不同的植物种类, 黄胸木蜂的访花行为和访花频率有差异。     

Food plants and foraging behaviors of Xylocopa appendiculata (Hymenoptera, Apidae) in Luoyang, Henan Province, central China

[目的]明确黄胸木蜂Xylocopa appendiculata 的访花植物种类和访花行为,为进一步开发和利用木蜂资源奠定基础.[方法]2009-2011年连续3年,在洛阳地区黄胸木蜂的活动期3-10月,采用目测、拍照等方法记录其访花植物及访花行为,记录和统计访花植物的生物学特征;测量访花植物种类被盗蜜后盗蜜口的大小.[结果]在洛阳地区黄胸木蜂访花植物种类为27科52种,主要的访花植物有25种.采访的植物种类中,忍冬科和豆科植物最多,分别为9种和8种,占采访植物种类的17.31％和15.38％;其中黄胸木蜂盗蜜的植物有16种,占其采访植物种类的30.77％.在采访的植物种类中,黄胸木蜂喜欢采访中等花型、两侧对称的紫色、黄色和白色花.在不同植物上,黄胸木蜂的盗蜜口大小和访花频率不同,黄胸木蜂在臭牡丹上的盗蜜口最大,为9.43±1.91mm,蝟实上的盗蜜口最小,为3.46±0.98 mm;在紫薇上的访花速度最快,访花频率为25.71±2.36朵/min;在蜀葵上的单花停留时间和访花间隔时间均最长,单花停留时间5.89±3.34 s,访花间]隔时间为2.63±2.04s.[结论]在洛阳地区黄胸木蜂访花植物种类多、访花时间长.对于不同的植物种类,黄胸木蜂的访花行为和访花频率有差异.     

草果两型植株的繁育差异研究

草果(Amomum tsaoko)是具有柱头卷曲机制的姜科植物,该研究通过观察和分析传粉者的访花行为、草果的花蜜分泌和最终的结实率,探索其花蜜分泌模式与传粉行为的相互关系,以及对其两型植株繁殖的影响。结果表明:草果两型植株的花蜜分泌在1 d花期的16:40—19:00期间达到高峰;上举型花比下垂型花能够提供更多的花蜜,下垂型花的花蜜分泌受环境温度、光照、湿度的显著影响,其结实率也显著低于上举型花。中华蜜蜂(Apis cerean cerana)是观察点频率最高的有效传粉者,在1 d花期里访花频率呈现双峰模式,访花行为受到温度和湿度的显著影响,78%或18℃较适宜访花。1 d花期中温度、湿度的变化,以及花蜜的动态分泌模式共同促进这一双峰访花模式的形成。草果花蜜分泌模式和双峰访花模式均与草果的柱头卷曲运动匹配,对吸引昆虫精确传粉、维持柱头卷曲机制有重要意义。草果两型植株之间,环境因素对它们花蜜分泌的影响显著不同,导致传粉者不同的访花行为反应和繁殖结果。适当增加居群中上举型植株数量,可能是提高产量的一个有效方法。     

云南草寇花序内不同部位的性分配

两性花植物花序内的性分配常存在差异,资源竞争、结构效应、交配环境(雌雄异熟、传粉者定向访花行为等)或授粉不均匀等几种假说可以解释这种现象。为验证上述假说,该研究以云南草寇两种表型(雄先熟型和雌先熟型)为材料,分析了其花序内不同部位(基部、中部和顶部)的每花花粉数、胚珠数、花粉/胚珠比、结实率和结籽率,花序内传粉者的定向访花行为,以及人工辅助授粉和去花处理对结实率和结籽率的影响。结果表明:两种表型花序内每花花粉数不随部位而变化,每花胚珠数、结实率和结籽率由基部到顶部依次降低,每花花粉/胚珠比由基部到顶部依次增加,表明顶部花存在偏雄的性分配。人工辅助授粉后,结实率、结籽率仍由基部到顶部依次降低,表明授粉不均匀假说不能解释云南草寇花序内不同部位结实率、结籽率的差异。去除基部和中部花后,顶部花人工辅助授粉条件下的结实率、结籽率与基部花人工辅助授粉条件下的结实率、结籽率无差异,表明云南草寇花序内不同部位结实率、结籽率的差异主要由资源竞争引起。雌先熟表型每花花粉数、花粉/胚珠比高于雄先熟表型,表明两种表型存在性分配差异。传粉者主要先访问云南草寇基部的花,然后向顶部移动。云南草寇花序内顶部偏雄的性分配可能是由资源竞争和传粉者定向访花造成的。     

盗蜜行为在植物繁殖生态学中的意义

在动植物的相互关系中,盗蜜行为被认为是一种不同于普通传粉者的非正常访花行为。动物之所以要采取这种特殊的觅食策略,有假说认为是由访花者的口器和植物的花部形态不匹配造成的,也有认为是盗蜜行为提高了觅食效率从而使盗蜜者受益。在盗蜜现象中,盗蜜者和宿主植物之间的关系是复杂的。盗蜜对宿主植物的影响尤其是对其繁殖适合度的影响归纳起来有正面、负面以及中性3类。与此同时,盗蜜者的种类, 性别及其掠食行为差异不仅与生境因素密切相关,而且会对宿主植物的繁殖成功产生直接或间接的影响。另外,盗蜜者的存在无疑对其它正常传粉者的访花行为也产生一定的影响,从而间接地影响宿主植物的繁殖成功, 而植物在花部形态上也出现了对盗蜜现象的适应性进化。作者认为, 盗蜜是短嘴蜂对长管型花最有效的一种掠食策略, 它不仅增加了盗蜜者对资源的利用能力, 而且由于盗蜜对宿主植物繁殖成功的不同的影响使其具有调节盗蜜者和宿主之间种群动态的作用, 两者的彼此适应是一种协同进化的结果。     

The use of floral resources by Visitors on Sparattosperma leucanthum (Vell.) K. Schum. (Bignoniaceae)

Aiming to estimate the rate of exploitation of the floral resources of Sparattosperma leucanthum (Vell.) K. Schum. as well as the interaction with their floral visitors in the pollination, the number of visits by flower was sampled, according to the type of visitation, the collected resource and the visitor's behavior during the forage for flowers. The floral visitors were grouped into seven guilds, organized in decreasing order of benefit to the S. leucanthum flower's pollination: effective pollinator, occasional pollinator, endogamic pollinator, generalist visitor, thievery visitor, thievery-pillager ant and pillager visitor. The total of 48.2 +/- 8.84 visits were recorded by flower. Nearly 50% of the visits resulted in nectar thief or pillage, which posed some problems to the reproduction of S. leucanthum, such as the drop in the attractiveness to pollinators and the harm to the flower's reproductive tissues. Trigona spinipes (Fabr.) (Hymenoptera: Apidae) was considered the most harmful species owing to the high frequency of pillage and forage. Bombus sp1, however, was probably the species that pollinated S. lecanthum flowers the most, making use of the crossed pollination.     

Reproductive conflicts ofPalicourea padifolia (Rubiaceae) a distylous shrub of a tropical cloud forest in Mexico

We studied a population of the distylousPalicourea padifolia (Rubiaceae) in a cloud forest remnant near Xalapa City, Veracruz, México to explore possible asymmetries between floral morphs in the attractiveness to pollinators, seed dispersers, nectar robbers, floral parasites, and herbivores. We first assessed heterostyly and reciprocal herkogamy by measuring floral attributes such as corolla length (buds and open flowers), style and anther heights, stigma and stamen lengths and the distance between the anther tip to the stigma lobe. We then estimated floral and fruit attributes such as flower size, anther height, number and size of pollen grains, fruit size, seed size, nectar production, and flower and fruit standing crops to assess differences between floral morphs in attracting and effectively using mutualistic pollinators and seed dispersers. Also, floral parasitism and nectar robbing were assessed in this study as a measure of flower attractiveness to antagonists. The system seems to conform well to classical heterostyly (e.g. reciprocal stamen/style lengths, pollen and anther dimorphism, intramorph incompatibility) yet, there were several tantalizing differences observed between pin and thrum morphs. Thrum flowers have longer corollas and larger but fewer pollen grains than pin flowers. Both morphs produced the same total number of inflorescences, developed the same number of buds, and opened the same number of flowers per inflorescence during the flowering season. Nectar production and sugar concentration were similar between floral morphs but the reward was not offered symmetrically to floral visitors throughout the day. Nectar concentration was higher in pin flowers in the afternoon. The numbers of developing, fully developed, and ripe fruits were the same between floral morphs, however, fruits and seeds were larger than those of thrums. The incidence of fly larvae was higher among thrum flowers and damage by nectar robbing was the same between floral morphs. Fruit abortion patterns of flowers manually pollinated suggest intra-morph sterility (self and intramorph incompatibility). There were no differences between morphs in fruit and seed set per flower following legitimate pollination although thrums were more leaky than the pins (intramorph compatibility).     

火把花的繁殖生物学研究

火把花（Colquhounia coccinea?）表现出典型的鸟媒综合征,因此具有作为引鸟景观植物的开发潜力。以自然、人工生境的火把花居群为研究对象,通过观察和试验对其开花物候、花部综合特征、访花动物及其行为、繁育系统、种子萌发特性进行研究,以明确火把花的繁殖特性及对不同访花动物的吸引潜力。结果显示,火把花的整体花期持续约3个月,单花花期为9.6±0.6 d;花蜜较丰富且稀薄,具有较短的花冠管和己糖为主的花蜜糖组成;访花动物主要是中华蜜蜂和多种食蜜鸟类,尤其是短喙的泛化鸟类,且在非自然生境中仍然能吸引鸟类访花;完全自交亲和但需要传粉者才能完成授粉,不存在花粉限制;不同授粉处理种子的发芽能力无显著差异;中华蜜蜂能有效传粉,鸟类的传粉作用需进一步验证。综上所述,火把花可供观赏的时间很长,具有明显的吸引鸟类访花的能力,容易通过有性繁殖途径快速获得大量幼苗。     

Pollination and breeding system of Couepia uiti (Mart. and Zucc.) Benth (Chrysobalanaceae) in the Pantanal da Nhecolandia.

The pollination biology and breeding system of Couepia uiti was studied. In this species, flowers opened at 06:00 AM anthesis, and nectar production began at around 0800 h, reached a maximum volume from 09:30 AM to 10:30 AM, and decreased thereafter. The nectar sugar concentration increased continuously, but showed an abrupt increase from 10:00 AM to 12:00 AM. Pollen release occurred at about 09:30 AM and was quickly collected. The stigmas became receptive at around 12:00 AM. The pollinators of C. uiti included the bees Apis mellifera, Xylocopa sp. and Bombus sp., and three species of wasps. This conclusion was based on the observation that these hymenopterans had C. uiti pollen on their bodies, visited the receptive flowers, and touched the anthers and stigmas, thereby promoting pollination. Of these floral visitors, A. mellifera was considered to be the most efficient pollinator. However, mixed pollination also occurred. The number of C. uiti flowers visited in the morning (n = 52) was three times smaller than in the afternoon (n = 62), and the species richness of floral visitors was also bigger in the afternoon (eight in the afternoon versus five in the morning). This finding indicated that these floral visitors preferred to exploit nectar rather than pollen. Controlled pollination experiments showed that C. uiti was a self-incompatible species that produced fruits only by cross-pollination. Treatments such as agamospermy and spontaneous and self-pollinations did not produce fruits.     

Pollination in Jacaranda rugosa (Bignoniaceae): euglossine pollinators, nectar robbers and low fruit set

Nectar robbers access floral nectar in illegitimate flower visits without, in general, performing a pollination service. Nevertheless, their effect on fruit set can be indirectly positive if the nectar removal causes an incremental increase in the frequency of legitimate flower visits of effective pollinators, especially in obligate outcrossers. We studied pollination and the effect of nectar robbers on the reproductive fitness of Jacaranda rugosa , an endemic shrub of the National Park of Catimbau, in the Caatinga of Pernambuco, Brazil. Xenogamous J . rugosa flowers continuously produced nectar during the day at a rate of 1 μl·h⁻¹. Female and male Euglossa melanotricha were the main pollinators. Early morning flower visits substantially contributed to fruit set because stigmas with open lobes were almost absent in the afternoon. Ninety-nine per cent of the flowers showed damage caused by nectar robbers. Artificial addition of sugar water prolonged the duration of flower visits of legitimate flower visitors. Removal of nectar, simulating the impact of nectar robbers, resulted in shorter flower visits of euglossine bees. While flower visits of nectar-robbing carpenter bees ( Xylocopa frontalis , X . grisescens, X . ordinaria) produced only a longitudinal slit in the corolla tube in the region of the nectar chamber, worker bees of Trigona spinipes damaged the gynoecium in 92% of the flowers. This explains the outstandingly low fruit set (1.5%) of J. rugosa in the National Park of Catimbau.     

Comparison of floral properties and breeding system in dimorphic Buddleja delavayi (Scrophulariaceae)

In this study, floral color, scent composition and emission rate, nectar property, pollinators, and breeding system of dimorphic Buddleja delavayi Gagnep. were investigated. Flower color of B. delavayi was determined using a standard color chart and spectrophotometer, and two distinct color polymorphisms were observed having purple or white flowers. Floral scents of B. delavayi were collected using dynamic headspace adsorption and identified with coupled gas chromatography and mass spectrometry. In total, 28 compounds were identified from the flowers of B. delavayi. The identified scents were divided into three chemical classes based on their biosynthetic origin: terpenes, fatty acid derivatives, and benzenoids. The scent profiles in all individuals were dominated by a few components, such as lilac aldehyde and alcohol, 4-oxoisophorone, benaldehyde, and oxoisophorone oxide. Floral scent composition (benzenoids and terpenes) showed a significant difference between white and purple flower morphs. Flower color–flower scent associations in B. delavayi were identified with two distinct scent profiles in the two color phenotypes. The studies of other floral characteristics (nectar, floral visitors, breeding system, and fruit set) indicated that floral scent emission rate, nectar volume, visitor visitation frequency, and natural fruit set were not significantly different between the two flower color morphs. Bagging experiments revealed that seed production of B. delavayi is dependent mainly on honeybee Apis cerana. Lastly, this study implies that dimorphic floral color in B. delavayi may have been maintained by floral visitors and nectar guide color.