2009年11月24日 星期二

傳粉者和植食者是否會造成花部化學特徵選汰上的衝突?

文獻來源:A Kessler & R Halitschke. 2009. Testing the potential for conflicting selection on floral chemical traits by pollinators and herbivores: predictions and case study. Functional Ecology 23: 901–912. doi: 10.1111/j.1365-2435.2009.01639.x

摘要
1.透過寄主植物在演化和行為上的反應,傳粉者和植食者能有許多種交互作用的方式。
2.由於傳粉者和植食者皆消費植物並依賴植物產生的營養和次級代謝物、以及利用植物訊息,植物化學應該是他們之間最主要的交互作用媒介。
3.作者建立了傳粉者和植食者之間以植物為媒介者的概念架構。作者著重在植物化學、尤其是植物揮發物,目標則在於統整植物防禦和傳粉的假說。作者提出對雙方演化結局的預測-傳粉者和植食者衝突的演化壓力起因於受植物化學之限制。
4.作者進一步提出植物為避免在“吸引傳粉者”與“抵禦植食者”之間產生衝突,能夠透過在特定組織調節對傳粉者的化學回饋、和由植食者引發的花部化學和形態之假說。
5.最後,作者利用野生種馬鈴薯(Solanum peruvianum)測試他們所預測的各個觀點,以闡述植物化學中“組織專一性”和“植食者誘導”之差異的多樣性,可能影響傳粉者與植食者之行為和植物的適應度。

SUMMARY
1. There are myriad ways in which pollinators and herbivores can interact via the evolutionary and behavioural responses of their host plants.
2. Given that both herbivores and pollinators consume and are dependent upon plant-derived nutrients and secondary metabolites, and utilize plant signals, plant chemistry should be one of the major factors mediating these interactions.
3. Here we build upon a conceptual framework for understanding plant-mediated interactions of pollinators and herbivores.
We focus on plant chemistry, in particular plant volatiles and aim to unify hypotheses for plant defence and pollination. We make predictions for the evolutionary outcomes of these interactions by hypothesizing that conflicting selection pressures from herbivores and pollinators arise from the constraints imposed by plant chemistry.
4. We further hypothesize that plants could avoid conflicts between pollinator attraction and herbivore defence through tissue-specific regulation of pollinator reward chemistry, as well as herbivore-induced changes in flower chemistry and morphology.
5. Finally, we test aspects of our predictions in a case study using a wild tomato species, Solanum peruvianum, to illustrate the diversity of tissue-specific and herbivore-induced differences in plant chemistry that could influence herbivore and pollinator behaviour, and plant fitness.

Key-words: plant–insect interactions, coevolution, plant defences, induced responses to herbivory, pollinator limitation

2009年11月22日 星期日

以分子序列初步重建鉤蛾總科親緣關係


A pilot study on the molecular phylogeny of Drepanoidea (Insecta: Lepidoptera) inferred from the nuclear gene EF-1a and the mitochondrial gene COI

文獻出處: Wu CG, Han HX, Xue DY. 2009. A pilot study on the molecular phylogeny of Drepanoidea (Insecta: Lepidoptera) inferred from the nuclear gene EF-1α and the mitochondrial gene COI. Bulletin of entomological research. 2009 Jul 7: 1-10 [Link]

簡介
本研究為中國科學院動物學組鱗翅目系統學研究組的武春光博士研究生、韓紅香與薛大勇博士,對鉤蛾總科類群首次進行分子親緣關係的重建,藉以初步釐清此總科內所含類群的單系性、各亞科間的關係,並以現有資訊討論長久具爭議性的鳳蛾科的分類歸屬。

由過去形態證據的研究中,鉤蛾、尺蛾、鳳蛾與燕蛾的分類地位與歸屬一直都有爭議。依據現今最被廣為使用的分類架構,鉤蛾總科包含了鳳蛾科與鉤蛾科,前者僅含少數屬與物種,而鉤蛾科中含鉤蛾亞科, 大鉤蛾亞科以及波紋蛾亞科共約700種描述種,其中鉤蛾亞科的Oreta屬常被提升為族級或亞科級地位。由於形態親緣關係的不穩定與研究者對不同特徵來定義分類階層的權重不一,近幾年來夜蛾科與尺蛾科使用多分子序列來進行高階親緣重建的方法也被應用在鉤蛾與鳳蛾分類群之上。

研究材料主要來自於舊北區中國產類群,包含鉤蛾總科的鳳蛾科2屬2種, 鉤蛾科11屬11種作為內群,外群選用夜蛾科與尺蛾科各2屬2種,表列於備註一並加入台灣產相關屬級或種級物種的網路影像連結。

方法上以核DNA EF-1
α序列以及結合EF-與粒腺體DNA COI序列所分別獲得的親緣樹顯示:
  1. 鳳蛾類群方面,兩屬兩物種Epicopeia hainesiPsychostrophia nymphidiaria形成單系群,此枝系在以EF-序列建構的樹型中與其他枝系關係不清楚,但在結合兩序列的樹型中與同為內群的鉤蛾科加上尺蛾科的枝系形成姊妹群,也就是在此分析結果中,過去鳳蛾歸屬於鉤蛾總科的處理並不適當。此結果在形態上可由鳳蛾並沒有鉤蛾科尺蛾的腹部聽器結構,以及此三分類群在前翅M脈系統、後翅Sc + R1脈與Rs脈關係之間的差異來支持。然而鳳蛾類群真正的分類地位可能需要涵蓋都多的尺蛾與燕蛾分類群與更多的分子序列來進行討論。
  2. 結合EF-與CII序列的樹型顯示廣義的鉤蛾科中Hypsomadius insignisOreta vatama形成單一枝系並與其他鉤蛾類群形成姊妹群,此結果對應形態上的特徵為HypsomadiusOreta的體型較壯碩呈黃褐色至棕色、下唇鬚短寬而密生毛束、口喙與翅刺(frenulum)不發達、後足脛節僅有一排等長的距刺;相對的其他鉤蛾姊妹群體修長呈白黃色、下唇鬚細長而分節明顯、口喙與翅刺皆發達、後足脛節有兩排距刺,兩枝系類群的生殖器結構亦有差異。本研究據此將過去提出的Oretinae亞科恢復使用,使現今鉤蛾總科包含四個亞科,然而作者承認所選取的分類群僅侷限於中國產物種,未來Oretinae類群與姊妹群間的關係尚須更多的分類群取樣來釐清。此外,馬達加斯加特產的 Nidarini(備註二)(包含五描述種)與其他鉤蛾亞科類群的關係應該也是未來待解決的問題。
  3. 鉤蛾亞科大鉤蛾亞科以及波紋蛾亞科在兩顆樹中都各自形成單系群,鉤蛾與大鉤蛾亞科形成姊妹群,以及此枝系與姊妹群大鉤蛾的樹型被高度的支持。此結果與Minet (2002)所提出的形態證據關係相符,他提出大鉤蛾相對波紋蛾與鉤蛾擁有較小且具有背方骨化區的聽器腔,此腔室的形態在大鉤蛾類群呈極度狹窄而至消失皆有。
備註一
Outgroup
Geometridae
Ennominae
Odontopera bilinearia coryphodes [Odontopera bilinearia subarida in Taiwan]
Geometrinae
Tanaorhinus viridiluteata [Tanaorhinus in Taiwan]
Noctuidae
Helicoverpa armigera [Species in Taiwan]
Catocala fraxini
[Catocala armandi shirozui in Taiwan]
Ingroup
Epicopeiidae
Epicopeia hainesi [Epicopeia mencia in Taiwan]
Psychostrophia nymphidiaria

Drepanidae
Cyclidiinae
Cyclidia substigmaria

Drepaninae
Callidrepana patrana [Species in Taiwan]
Ditrigona conflexaria
[D. triangularia in Taiwan]
Hypsomadius insignis [Species in Taiwan]
Macrocilix maia
[Species in Taiwan]
Macrocilix mysticata [M. mysticata flavotincta in Taiwan]
Microblepsis leucosticta
[M. violacea in Taiwan]
Oreta vatama
[O. loochooana in Taiwan]
Tridrepana fulvata
[T. flava in Taiwan]
Thyatirinae
Gaurena fletcheri

Habrosyne conscripta
[H. fraterna chekiangensis in Tawian]
Parapsestis lichenea


備註二
Minet與Scoble (1999)提出的鉤蛾亞科可分為三個族級分類群: 鉤蛾族 Oretini族以及Nidarini族

鉤蛾總科與相關參考文獻
1. Holloway JD. 1998. The Moths of Borneo: Families Castniidae, Callidulidae, Drepanidae and Uraniidae. The Malayan Nature Journal 52: 1–155.
2. Minet J. 2002. The Epicopeiidae: Phylogeny and a redefinition, with the description of new taxa (Lepidoptera: Drepanoidea). Annales de la Societe Entomologique de France 38: 463–487.
3. Minet J and Scoble MJ. 1999. The drepanoid/geometroid assemblage. pp. 301–320 in Kristensen NP (Ed.) Handbook of Zoology, Vol. IV. Arthropoda: Insecta. Part 35. Lepidoptera, Moths and Butterflies. Berlin & New York, Walter de Gruyter.
4. Nakajima H. 1970. A contribution to the knowledge of the immature stages of Drepanidae occurring in Japan. Tinea 8: 167–184.

Abstract
A molecular phylogenetic study of the Drepanoidea based on the EF-
sequences and combined EF-1α and COI sequences was carried out in order to infer higher classification at and above the subfamily level. The sample contained 14 taxa representing 13 genera recognized in the Drepanoidea. The results revealed that the Drepaninae, Thyatirinae and Cyclidiinae respectively form monophyletic groups. The sister relationship between the Drepaninae and the Thyatirinae was validated. The monophyly of the Cyclidiinae with the Drepaninae+Thyatirinae was supported robustly. Hypsomadius insignis and Oreta vatama within the traditional definition of the Drepaninae formed an individual clade with robust support (100%) and constitutes a sister relationship to a clade containing the rest of the Drepaninae in all the topologies, which means that the subfamily Oretinae of the Drepanidae should be restored. The family Drepanidae is divided into four subfamilies: Drepaninae, Oretinae, Thyatirinae and Cyclidiinae in this work. The family Epicopeiidae formed a monophyly with high bootstrap values. The result of combined analysis of EF- and COI showed that the Epicopeiidae have a closer phylogenetic relationship with the Geometridae than with the Drepanidae and belong to neither the Drepanoidea nor the Geometroidea.

蝶類不孕精子與雌性接受能力之共演化


圖片來源:treknature
文獻來源:N Wedell , C Wiklund and J Bergstro¨m. 2009. Coevolution of non-fertile sperm and female receptivity in a butterfly. Biology letters 5: 678–681. doi:10.1098/rsbl.2009.0452 (Published online 29 July 2009)

兩性之間的衝突可促進雄性與雌性生殖特徵的快速演化。許多採行一妻多夫制蝶類的雄蟲在交尾時會傳遞營養物質給雌性以促進雌性的繁殖力,但是當雌性再次與其他雄蟲交尾、造成精子競爭時變產生了兩性的衝突。蝴蝶同時製造了可孕的精子和大量不可孕的精子。暗脈粉蝶(Pieris napi) 的不可孕精子充滿了雌蟲的儲精囊,關閉雌蟲繼續接受精子的能力而降低雌性再次交尾之可能。雌蟲儲存不孕精子的量具有遺傳上的變異,此與雌性抵抗雄性策略的 不反應期有直接相關。雄蟲的精子生產亦有遺傳上的變異。本文中,作者以量化遺傳學和選汰實驗顯示雌蟲的不反應期與雄蟲精子產量具有遺傳上的相關性。發生在 雄蟲操縱組之選汰可能增加雌蟲的接受操縱組雄蟲的頻率,成為一相關的反應,反之亦然。

Sexual conflict can promote rapid evolution of male and female reproductive traits. Males of many polyandrous butterflies transfer nutrients at mating that enhances female fecundity, but generates sexual conflict over female remating due to sperm competition. Butterflies produce both normal fertilizing sperm and large numbers of non-fertile sperm. In the green-veined white butterfly, Pieris napi, non-fertile sperm fill the females’ sperm storage organ, switching off receptivity and thereby reducing female remating. There is genetic variation in the number of non-fertile sperm stored, which directly relates to the female’s refractory period. There is also genetic variation in males’ sperm production. Here, we show that females’ refractory period and males’ sperm production are genetically correlated using quantitative genetic and selection experiments. Thus selection on male manipulation may increase the frequency of susceptible females to such manipulations as a correlated response and vice versa.