Morphometric variability in a population of the root vole

Abstract

Jan u sz M ARKOW SKI M arkow ski J., 1980: M orphom etric v aria b ility in a p o p ulation of th e root vole. A cta theriol., 25, 14: 155—211 [W ith 10 T ables & 13 Figs.]. E x am in atio n w as m ade of v a ria b ility in body an d skull dim ensions in a p opulation of th e root vole Microtus oeconomus (Pallas, 1776) living in a d rain e d sphagnum bog in th e A ugustów F o rest (eastern Poland). A nalysis w as m ade of m a te ria l consisting of 2424 in dividuals caught over an 9-year period (1966— 1974), tak in g into consideration sex dim orphism , differences in seasonal generatio n s and rela tio n to dynam ics of population num bers. The study population was su b ject to considerable p ressu re from the changing h ab itat (grow th of tree p la n tatio n s) and its n u m b e rs decreased in successive years. Sex dim orphism is p artic u la rly distinct in old ad u lts, body and skull dim ensions of m ales being significantly g re a te r th a n those of fem ales. D ifferences in these dim ensions in young anim als are seasonal in ch a racter. F em ales of the spring g en eratio n grow m ore rap id ly and a tta in g re a te r dim ensions th a n m ales, w h ereas it is th e la tte r w hich have g re a te r body dim ensions in the au tu m n g eneration. R eduction in m ean values w as found in successive years and in th e ranges of v a ria tio n in body and skull m e asu rem en ts observed, but th is was sta tistica lly significant only in the case of body length and w eight. V ariatio n s in body dim ensions w ere n o t correlated w ith v ariatio n s in the n u m b e rs of voles. [Dep. Comp. A nat. & A nim al Ecol., Univ. of Łódź, B anacha 12/16, 90-237 (present address), an d M am m als Res. Inst., P olish Acad. Sci., 17-230 B iałow ieża, Poland] I. INTROD U CTIO N In studies on v a ria b ility in m am m als it is possible to distinguish two classic tren d s in biology: the first, th e purpose of w hich is to present the fact itself and describe v aria b ility ; the second is genetic a n d populational in aspect, as the expression of adaptation 'to the h a b ita t (Schwarz, 1969; Yablokov, 1966; M a y r, 1974). O ne of the m anifestations of intraipopulation heterogeneity about w hich considerable inform ation has been ¡obtained is m orphological variab ility . This applies iboth to q u a lita tiv e and q u a n tita tiv e c h aracteristics (see Yablokov, 1966). A nalysis of m orphological characteristics, as additional to th eir classical application in system atic«, 1155J