螞蟻和某些植物具有典型的互利共生關(guān)系,，植物為螞蟻提供食宿,，換來的是螞蟻有效地抵御植物的入侵者,。然而，最新一項(xiàng)研究顯示,，這種互利互惠的關(guān)系看上去并不完美,，往往螞蟻破壞了植物的性繁殖,。
節(jié)果決明（Cordia nodosa）是一種與螞蟻共生的南美洲植物,，Allomerus octoarticulatus是與節(jié)果決明植物一起生存的螞蟻物種之一，它們?cè)谝黄鹕顣r(shí),，這種螞蟻既充當(dāng)著朋友,，也充當(dāng)著破壞者，盡管它們可以保護(hù)螞蟻,，但同時(shí)卻破壞了植物,，使其無法繁殖。
科學(xué)家推測(cè)螞蟻能夠迫使植物將營(yíng)養(yǎng)物質(zhì)主要用于生長(zhǎng),，而不是結(jié)出果實(shí)和種子,。節(jié)果決明樹枝的中空節(jié)結(jié)叫做“蟲菌穴（domatia）”，螞蟻在蟲菌穴里居住,，同時(shí)以植物上生產(chǎn)甘露的介殼蟲為食,。如果節(jié)果決明植物生長(zhǎng)得更快，那么植物體上就有更多的蟲菌穴,，能夠使螞蟻殖民地進(jìn)一步擴(kuò)張,。
為了測(cè)試這項(xiàng)假設(shè)，美國(guó)哈佛大學(xué)生態(tài)學(xué)家梅甘－弗雷德里克遜（Megan E. Frederickson）前往秘魯對(duì)節(jié)果決明和寄居的阿芝臺(tái)螞蟻進(jìn)行了觀察,，為了模擬阿芝臺(tái)螞蟻的共生效果,，她對(duì)節(jié)果決明植物剪去了所有的花朵，之后她發(fā)現(xiàn)這種節(jié)育后的植物生長(zhǎng)速度是其他未剪去花朵植物的4倍,。
然而被剪裁花朵的螞蟻寄居的螞蟻并不意味著終結(jié)節(jié)果決明植物的性繁殖能力,，這種植物在生命歷程中能夠寄居多種螞蟻，最終某種螞蟻能夠使該植物的繁殖能力再度興旺發(fā)育,。
目前,，這項(xiàng)研究報(bào)告發(fā)表在近日已出版的《美國(guó)博物學(xué)家》（American Naturalist）雜志上。（生物谷Bioon.com）
生物谷推薦原始出處：
Am Nat 2009. Vol. 173, pp. 675–681 DOI: 10.1086/597608
Conflict over Reproduction in an Ant‐Plant Symbiosis: Why Allomerus octoarticulatus Ants Sterilize Cordia nodosa Trees
Megan E. Frederickson*
Society of Fellows and Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts 02138
The evolutionary stability of mutualism is thought to depend on how well the fitness interests of partners are aligned. Because most ant‐myrmecophyte mutualisms are persistent and horizontally transmitted, partners share an interest in growth but not in reproduction. Resources invested in reproduction are unavailable for growth, giving rise to a conflict of interest between partners. I investigated whether this explains why Allomerus octoarticulatus ants sterilize Cordia nodosa trees. Allomerus octoarticulatus nests in the hollow stem domatia of C. nodosa. Workers protect C. nodosa leaves against herbivores but destroy inflorescences. Using C. nodosa trees with Azteca ants, which do not sterilize their hosts, I cut inflorescences off trees to simulate sterilization by A. octoarticulatus. Sterilized C. nodosa grew faster than control trees, providing evidence for a trade‐off between growth and reproduction. Allomerus octoarticulatus manipulates this trade‐off to its advantage; sterilized trees produce more domatia and can house larger, more fecund colonies.
