摘要
高原鼢鼠(Myospalax baileyi)是青藏高原典型的地下鼠,它主要挖掘取食杂类草之地下根茎,在挖掘过程中形成取食洞道。本文根据此特点,建立了挖掘取食过程中能量代价(E_(?))与取食道结构参数(土丘间距S、侧道长L、取食道半径b及洞道深度D)之间以及取食获能E_(fg)与S和b之间的两个函数关系。分别以挖掘效率极大和取食效率极大为优化目标,导出同样的结果,即相同的最佳土丘间距S_(opt)。通过实验观测,计算出在矮嵩草(Kobresiahumilis)草甸生境条件下,最佳土丘间距S_(opt)=127.4厘米,与野外实测土丘间距(126.30±47.85厘米)无显著差异(t=0.312,P>0.50),表明高原鼢鼠的挖掘及取食行为符合最佳化原则。
This paper deals with the optimal foraging and burrowing of the plateau zokor (Myospalax baileyi), a typical species of fossorial rodent distributed on Qinghai-Tibet Plateau, based on the following two hypotheses;
H1: If burrowing is optimal, burrowing efficiency would be maximum which means that burrowing a certain length expends a minimal energy.
H2: If foraging is optimal, foraging benefit to the cost would be maximum.
According to the zokor's foraging burrow structure and observed behavioural characteristics associated with foraging by burrowing, a model slightly distinguishing from equation 2 of Vleck (1981) was established for describing the energy cost of foraging by burrowing.
Ec=Ks·C·(S + L)+(Kp·C + Kt/A)·(S2/2 + 2S·L + L2)+5D·g·C2S (a)
where EC = energy cost of excavating a segment of foraging burrow, S =segment length (distance between two adjacent laterals or mounds), L =lateral length, D = burrow depth, C = π·b2·ρ,in which p is soil density in terms of soil mass per unit volume and b the radium of burrow, g = gravitational acceleration, Ks= energy cost of shearing 1 g of soil loose, Kp = energy cost of pushing 1 g soil a centimeter, Kt = energy cost of travelling one centimeter, A = length of a small piece of burrow, when which established the loose soil must be pushed out.
Having a complete segment established, the energy benefit of a zokor from soil can be described by the following equation:
Efg =π·b2·S·De·Ra (b)
where Efg = assimilable energy gained from soil of a segment, De = energy in food available for zokor per unit volume of soil, Ra = assimilating rate of food by zokor.
From the two hypotheses, (Ec/S) would be minimum (H1) and (Efg/Ec maximum (H2). Thus, it could be deduced that segment must meet the following definition:
Sopt =[2L2 + 2Ks · C · L/(KP · C + Kt/A)]1/2 (c)
which made H1 and H2 stand.
On the basis of data of burrowing metabolic rate, burrowing rate (bu
出处
《兽类学报》
CAS
CSCD
北大核心
1992年第2期117-125,共9页
Acta Theriologica Sinica
基金
国家自然科学基金
中国科学院海北高寒草甸生态系统定位站基金资助项目
关键词
高原鼢鼠
挖掘取食
能量代价
Plateau zokor (Myospalax baileyi)
foraging by burrowing
energy cost
efficiency
