日前,，科學(xué)家發(fā)現(xiàn)不管是蟑螂還是毛蟲，它們在死亡之后，都會(huì)散發(fā)出具有惡臭的酸性脂肪類混合物，而這種氣味能夠驅(qū)趕室內(nèi)所有昆蟲,。
加拿大麥克馬斯特大學(xué)(McMaster University)生物學(xué)家大衛(wèi)·羅洛(David Rollo)在研究蟑螂上午社會(huì)行為時(shí)發(fā)現(xiàn)了這種奇怪現(xiàn)象。他發(fā)現(xiàn),，蟑螂在找到處所的時(shí)候（比如像廚房的碗櫥），會(huì)散發(fā)出一種化學(xué)信號,，來吸引它的同類,。為了查明這種化學(xué)物質(zhì)的具體成份，羅洛和他的團(tuán)隊(duì)就將死亡的蟑螂身體搗碎,，然后把它們的體液撒播在一些事先找好的地方,。
羅洛表示：“我們驚奇的發(fā)現(xiàn)，蟑螂在爬行的時(shí)候,，會(huì)避開這些撒播了死蟑螂提取物的地方,。于是，我們就想查出,，到底是什么物質(zhì)讓它們要避開這些地方,。”
不過，要想最終查明這種物質(zhì),，必須查證其它蟲子是否會(huì)在死亡后散發(fā)出驅(qū)趕同類的味道,。大衛(wèi)·羅洛和其同事經(jīng)過試驗(yàn)發(fā)現(xiàn)，不僅僅是蟑螂,，在螞蟻,、毛蟲、樹虱以及潮蟲身上，都存在此類現(xiàn)象,。盡管,，從分類上來說，這些動(dòng)物都屬于甲殼類動(dòng)物,，而不是昆蟲,，但是從功能上來講，他們散發(fā)出酸性脂肪類混合物是一樣的,。
雖然早在4億年前,，昆蟲和甲殼類動(dòng)物就開始分屬于不同物種，但是研究人員認(rèn)為,，它們死后散發(fā)出酸性脂肪類混合物這種現(xiàn)象是普遍存在,，而且從功能上來講是一樣，主要表示一種警告信號,。羅洛在公布研究報(bào)告的時(shí)候就表示：“確認(rèn)同類死亡后,，并且避免和它們靠近，能夠減少感染疾病的幾率,。而且,，這種方法也能讓動(dòng)物激活自身免疫能力。”
科學(xué)家希望能夠?qū)⑺劳龊罄ハx的這種氣味混合物提煉出來,，并且通過這種方法來保護(hù)農(nóng)作物免受害蟲侵害,。比如說，在原木上涂上酸性脂肪類混合物,，能夠讓其在一個(gè)月內(nèi)不會(huì)受到木蠹蛾的侵害,。
不過，幸運(yùn)的是,，人類的鼻子還無法辨別出這種酸性脂肪類提取物,。羅洛在一份電子郵件當(dāng)中稱：“腐爛的尸體散發(fā)出的氣味在遠(yuǎn)處是無法聞到的。我試著將這種氣味的提取物涂到紙上,，但我并沒有聞到有刺激性的味道,，并且我也不排斥這種氣味。”
研究人員已經(jīng)把這項(xiàng)科學(xué)成果發(fā)表在今年9月刊的Evolutionary Biology上,。（生物谷Bioon.com）
生物谷推薦原始出處：
Evolutionary Biology DOI:10.1007/s11692-009-9069-4
The Ancient Chemistry of Avoiding Risks of Predation and Disease
M. Yao1, J. Rosenfeld2, S. Attridge1, S. Sidhu1, V. Aksenov1 and C. D. Rollo1
(1) Department of Biology, McMaster University, 1280 Main St. W, Hamilton, Ontario, L8S 4K1, Canada
(2) Department of Pathology and Molecular Medicine, McMaster University, 1280 Main St. W, Hamilton, Ontario, L8S 4K1, Canada
Abstract Illness, death, and costs of immunity and injury strongly select for avoidance of predators or contagion. Ants, cockroaches, and collembola recognize their dead using unsaturated fatty acids (e.g., oleic or linoleic acid) as “necromone” cues. Ants, bees, and termites remove dead from their nests (necrophoric behavior) whereas semi-social species seal off corpses or simply avoid their dead or injured (necrophobic behavior). Alarm and avoidance responses to exudates from injured conspecifics are widespread. This involves diverse pheromones, complex chemistry and learning. We hypothesized that necromones are a phylogenetically ancient class of related signals and predicted that terrestrial Isopoda (that strongly aggregate and lack known dispersants) would avoid body fluids and corpses using fatty acid “necromones.” Isopods were repelled by crushed conspecifics (blood), intact corpses, and alcohol extracts of bodies. As predicted, the repellent fraction contained oleic and linoleic acids and authentic standards repelled several isopod species. We further predicted a priori that social caterpillars (lacking known dispersants) would be repelled by their own body fluids and unsaturated fatty acids. Both tent caterpillars and fall webworms avoided branches treated with conspecific body fluid. Oleic and linoleic acids were also strongly avoided by both species. Necromone signaling appears widespread and likely traces to aquatic ancestors pre-dating the divergence of the Crustacea and Hexapoda at least 420 million years ago.
