科研人員發(fā)現(xiàn)，盡管單個(gè)螞蟻可能在水中掙扎,，一群火蟻可以相互連接起來(lái)并攔截空氣從而形成一個(gè)防水的筏。為了探索入侵紅火蟻（Solenopsis invicta）如何形成這種筏,，David Hu及其同事把500只到8000只的螞蟻群投入到了水面上,。這些螞蟻迅速在水上聚集，在幾分鐘時(shí)間里就穩(wěn)定下來(lái),，形成了一個(gè)餅狀結(jié)構(gòu),，其中大約一半的螞蟻形成了一個(gè)浸入水中的單層，讓其余的螞蟻漂浮起來(lái),。這組作者報(bào)告說(shuō),，在這些筏的下面截住的空氣很可能增加了浮力并且防止了底層的螞蟻被淹死。測(cè)試表明,，這些螞蟻通過(guò)相互咬住對(duì)方的下顎與爪從而連接起來(lái),，形成了類(lèi)似于防水纖維的編織結(jié)構(gòu)。當(dāng)這組科研人員從一個(gè)筏的頂層一只一只地拿走螞蟻的時(shí)候,，底層的螞蟻向上運(yùn)動(dòng)從而保持筏的平均厚度,。這組科研人員提出，浸入水中的螞蟻可能有能力感知有多少蟻群成員在水面之上行走,。這組作者指出,，在組成筏的時(shí)候，在筏的邊緣的螞蟻被鄰近的螞蟻攔截住,，這提示這種看上去的合作行為可能依賴(lài)于強(qiáng)迫,。（生物谷Bioon.com）
生物谷推薦原文出處：
PNAS doi: 10.1073/pnas.1016658108
Fire ants self-assemble into waterproof rafts to survive floods
Nathan J. Mlota, Craig A. Toveyb, and David L. Hua,c,1
Abstract
Why does a single fire ant Solenopsis invicta struggle in water, whereas a group can float effortlessly for days? We use time-lapse photography to investigate how fire ants S. invicta link their bodies together to build waterproof rafts. Although water repellency in nature has been previously viewed as a static material property of plant leaves and insect cuticles, we here demonstrate a self-assembled hydrophobic surface. We find that ants can considerably enhance their water repellency by linking their bodies together, a process analogous to the weaving of a waterproof fabric. We present a model for the rate of raft construction based on observations of ant trajectories atop the raft. Central to the construction process is the trapping of ants at the raft edge by their neighbors, suggesting that some “cooperative” behaviors may rely upon coercion.
