注册 登录  
 加关注
   显示下一条  |  关闭
温馨提示!由于新浪微博认证机制调整,您的新浪微博帐号绑定已过期,请重新绑定!立即重新绑定新浪微博》  |  关闭

我的大学生活

让我们放飞梦想,在真理和知识的天空自由翱翔

 
 
 

日志

 
 
 
 

Ornithophily and Zoophily  

2009-08-14 03:45:41|  分类: 生物遗传天地 |  标签: |举报 |字号 订阅

  下载LOFTER 我的照片书  |

Ornithophily

From Wikipedia, the free encyclopedia

Ornithophily - 鹏程万里 - 我的大学生活

Ornithophily - 鹏程万里 - 我的大学生活

Hummingbird Phaethornis longirostris on an Etlingera inflorescence

Ornithophily is the pollination of flowering plants by birds. This coevolutionary association is derived from insect pollination (entomophily) and is particularly well developed in some parts of the world, especially in the tropics and on some island chains.[1] The association involves several distinctive plant adaptations forming a "pollination syndrome". The plants typically have colourful, often red, flowers with long tubular structures holding ample nectar and orientations of the stamen and stigma that ensure contact with the pollinator. Birds involved in ornithophily tend to be specialist nectarivores with brushy tongues, long beaks, capable of hovering flight or are light enough to perch on the flower structures.

Contents

[hide]

Plant adaptations

Ornithophily - 鹏程万里 - 我的大学生活

Ornithophily - 鹏程万里 - 我的大学生活

A Green Violet-ear

Ornithophily - 鹏程万里 - 我的大学生活

Ornithophily - 鹏程万里 - 我的大学生活

Inflorescences of Butea allow birds to perch on the stalk[2][3]

Bird pollination is considered as a costly strategy for plants and it evolves only where there are particular benefits for the plant.[4] High altitude ecosystems that lack insect pollinators, those in dry regions or isolated islands tend to favour the evolution of ornithophily in plants.[5]

Plants adaptations may be grouped into mechanisms that attract birds, those that exclude insects,[6] protect against nectar theft and pollination mechanisms in the strict sense.[5] The ovules of bird flowers also tend to have adaptations that protect them from damage.[7]

Most bird pollinated flowers are red and have a lot of nectar. They also tend to be unscented.[8] Flowers with generalist pollinators tend to have dilute nectar but those that have specialist pollinators such as hummingbirds or sunbirds tend to have more concentrated nectar.[9][10] The nectar of ornithophilous flowers vary in the sugar composition, with hexoses being high in passerine pollinated species while those that are insect pollinated tend to be sucrose rich. Hummingbird pollinated flowers however tend to be sucrose rich.[11] Many plants of the family Loranthaceae have explosive flowers that shower pollen on a bird that forages near it. They are associated mainly with flowerpeckers in the Dicaeidae family.[12] In Australia, some species of Banksia have flowers that open in response to bird actions thereby reducing the wastage of pollen.[13] As many as 129 species of North American plants have evolved ornithophilous associations.[14] Nearly a fourth of the 900 species of the genus Salvia are bird pollinated in the South African region.[15]

The rat's tail babiana (Babiana ringens Ker Gawl.) is a species of plant that produces a strong stalk within the inflorescence that serves as a perch for the Malachite Sunbird as it visits the flower.[5] Heliconias have special sticky threads that help in the adhesion of pollen to smooth structures such as the bill of a hummingbird.[16] Some African orchids of the genus Disa have pollinaria that stick to the feet of visiting sunbirds.[17]

Plants need to protect against nectar being taken by non-pollinators. These agents are classified into nectar robbers, which may destroy the flower, for example cut the flower at the base to obtain nectar and nectar thieves that obtain nectar without pollinating the flower.[18]

Bird adaptations

Ornithophily - 鹏程万里 - 我的大学生活

Ornithophily - 鹏程万里 - 我的大学生活

Ruby-throated Hummingbird (Archilochus colubris) at scarlet beebalm flowers (Monarda didyma)

The main families of specialized nectar feeding birds that are involved in ornithophily are the hummingbirds (Trochilidae), sunbirds (Nectariniidae), and the honey-eaters (Meliphagidae). Other important bird groups include those in the families the Icteridae, the honeycreepers (Thraupidae, Drepanidae), white-eyes (Zosteropidae) and the South African sugar-birds (Promeropidae). Birds may obtain nectar either by perching or by hovering with the latter mainly found in the hummingbirds and sunbirds. Within the hummingbirds, two kinds of foraging are noted with territorial "hermit" hummingbirds and the non-hermits which forage longer distances [5]

Hummingbirds have the ability to digest sucrose unlike many passerines that prefer hexoses (fructose and glucose). Starlings and their relatives will completely avoid sucrose.[19] Nectar feeding birds typically have a mechanism to quickly excrete excess water. They may have to drink four to five times their body mass of liquid during the day to obtain enough energy.[20] Hummingbirds are capable of excreting nitrogenous wastes as ammonia since they can afford more water loss than birds that feed on low-moisture food sources.[21][22] Hummingbirds and sunbirds also have special anatomical and physiological adaptations that allow them to quickly excrete excess water. Hummingbirds are also able to turn off their kidney function at night.[23]

In some birds such as white-eyes, the pollen dusted by the plants on the forehead of the birds may increase the wear of these feathers leading to increased moulting and replacement.[24]

Other associations

Several mite species (mainly in the genera Proctolaelaps, Tropicoseius and Rhinoseius, family Ascidae) have evolved a phoretic mode of life, climbing into the nostrils of hummingbirds that visit flowers and hitching a ride to other flowers where they can feed on the nectar. Hummingbird flower mites favour plants in the familes of Heliconiaceae, Costaceae, Zingiberaceae, Amaryllidaceae, Rubiaceae, Apocynaceae, Bromeliaceae, Gesneriaceae,Lobeliaceae and Ericaceae, members of which are associated with Hummingbirds.[25]

Zoophily

Ornithophily  and   Zoophily - 鹏程万里 - 我的大学生活

Ornithophily  and   Zoophily - 鹏程万里 - 我的大学生活

A Rufous Hummingbird (Selasphorus rufus) is attracted to brightly colored flowers and assists the pollination of the plant.

Zoophily is a form of pollination whereby pollen is transferred by vertebrates, particularly by hummingbirds and other birds, and bats, but also by monkeys, marsupials, lemurs, bears, rabbits, deer, rodents, lizards and other animals. Zoomophilous species, like entomophilous species, frequently evolve mechanisms to make themselves more appealing to the particular type of pollinator, e.g. brightly colored or scented flowers, nectar, and appealing shapes and patterns. These plant animal relationships are often mutually beneficial because of the food source provided in exchange for pollination. Zoophilous species include Arctium, Acaena, and Galium aparine.

Pollination is defined as the transfer of pollen from the anther to the stigma (Worldnet). There are many vectors for pollination, including abiotic (wind and water), and biotic (animal). There are different benefits and costs associated with any vector type. For instance, using animal pollination is beneficial because the process is more directed and often results in pollination. At the same time it is costly for the plant to produce rewards, such as nectar, to attract animal pollinators. Not producing such rewards is one benefit of using abiotic pollinators, but a cost associated with this approach is that the pollen may be distributed somewhat randomly. In general, pollination by vertebrates occurs when the animal reaches inside the flowers for nectar. While feeding on the nectar, the animal rubs or touches the stamens and is covered in pollen. Some of this pollen will be deposited on the stigma of the next flower it visits, pollinating the flower (Missouri Botanical Garden 2006).

  评论这张
 
阅读(332)| 评论(0)
推荐 转载

历史上的今天

评论

<#--最新日志,群博日志--> <#--推荐日志--> <#--引用记录--> <#--博主推荐--> <#--随机阅读--> <#--首页推荐--> <#--历史上的今天--> <#--被推荐日志--> <#--上一篇,下一篇--> <#-- 热度 --> <#-- 网易新闻广告 --> <#--右边模块结构--> <#--评论模块结构--> <#--引用模块结构--> <#--博主发起的投票-->
 
 
 
 
 
 
 
 
 
 
 
 
 
 

页脚

网易公司版权所有 ©1997-2018