生物學(xué)家一直認(rèn)為植物和授粉昆蟲間的相互作用加速了進(jìn)化中的演變,、提高了物種的多樣性,。然而,，新的研究成果表明植物與授粉者們之間的相互作用并不是如之前所想象的那樣能夠增加生物的多樣性，相反的,，在某種情況下是減少的,。
新發(fā)現(xiàn)顯示Joshua tree和為其授粉的蛾，如Tegeticula Synthetica之間的協(xié)同進(jìn)化并沒有像之前人們想象的那樣促進(jìn)多樣性增加,，反而是使其減少的,。
這項發(fā)表在《進(jìn)化生物學(xué)期刊》（Journal of Evolutionary Biology） 上的研究結(jié)果顯示位于Mojave Desert的一種當(dāng)?shù)刈钣刑厣闹参?mdash;—Joshua tree——并不像預(yù)期中的那樣具有生物多樣性,。如果沒有某種特殊的蛾為其的花朵授粉的話，Joshua tree將無法產(chǎn)生種子,。之前的研究結(jié)果顯示生物多樣性存在于Joshua tree和為它進(jìn)行授粉的蛾之間：那些具有很長的產(chǎn)卵器的蛾往往喜歡具有較大花朵,，而產(chǎn)卵器較小的蛾則傾向于較小的花朵。因此,，生物學(xué)家們猜測蛾的這種特 點與當(dāng)?shù)仫@花植物相互適應(yīng)并達(dá)到繁殖的目的,。但是在結(jié)合數(shù)學(xué)建模以及野外觀察之后，研究者們發(fā)現(xiàn)物種間的生物多樣性并不顯著,，同時也沒有證據(jù)能表明當(dāng)?shù)氐?蛾適應(yīng)當(dāng)?shù)氐腏oshua tree,。
“我們之前就已經(jīng)觀察到了兩種類型的蛾：較大的蛾偏好較大的花朵，而較小的蛾則喜歡較小的花朵,。但是當(dāng)我們試圖去解釋這種差異時,，我們發(fā)現(xiàn)沒有證據(jù)說明蛾已經(jīng)適應(yīng)了這些花。”負(fù)責(zé)這項研究的來自于國家數(shù)學(xué)和生物綜合研究所的博士后William Godsoe說道,。（生物谷Bioon.com）
生物谷推薦原文出處：
J Evol Biol. 2010 Dec;23(12):2739-46.
Absence of population-level phenotype matching in an obligate pollination mutualism.
Godsoe W, Yoder JB, Smith CI, Drummond CS, Pellmyr O.
National Institute for Mathematical and Biological Synthesis, University of Tennessee, Knoxville, TN 37996-1527, USA. [email protected]
Abstract
Coevolution is thought to promote evolutionary change between demes that ultimately results in speciation. If this is the case, then we should expect to see similar patterns of trait matching and phenotypic divergence between populations and between species in model systems for coevolution. As measures of divergence are frequently only available at one scale (population level or taxon level), this contention is rarely tested directly. Here, we use the case of co-divergence between different varieties of Joshua tree Yucca brevifolia (Agavaceae) and their obligate pollinators, two yucca moths (Tegeticula spp. Prodoxidae), to test for trait matching between taxa and among populations. Using model selection, we show that there is trait matching between mutualists at the taxon level, but once we account for differences between taxa, there is no indication of trait matching in local populations. This result differs from similar studies in other coevolving systems. We hypothesize that this discrepancy arises because coevolution in obligate mutualisms favours divergence less strongly than coevolution in other systems, such as host–parasite interactions.
