Geographical variation in body size of the Wood Mouse Apodemus sylvaticus L.

Abstract

This paper analyses the geographical variation in body size of the Wood Mouse. A size increase is observed from north to south, contrary to Bergmann's rule. This increase is related to regions of sympatry and allopatry with the Yellow‐necked Mouse, a closely related, potentially competing species. The possibility of character displacement playing an important role in determining the observed variation in body size is discussed.

No recent temporal changes in body size of three Danish rodents

“…It is an opportunistic species and eats a varied diet of seeds, seedlings, buds, fruit, nuts, fungi, moss, snails, insect larvae, earthworms and centipedes (Macdonald and Barrett 1993;Macdonald and Tattersall 2001). In Europe, body size of the wood mouse varies geographically and increases from north to south, contrary to Bergmann's rule (Alcantara 1991). This phenomenon is related to regions of sympatry and allopatry with the yellow-necked mouse (Apodemus flavicollis), and may also be related to character displacement (Alcantara 1991), with the larger yellow-necked mouse negatively affecting the smaller wood mouse.…”

Test of character displacement in urban populations of <i>Apodemus sylvaticus</i>

“…The phenomenon of morphological differences between populations that occur in the presence and absence of a competitor has been repeatedly demonstrated in several vertebrate taxa such as lizards (Losos 1990;Giannasi et al 2000), birds (Lack 1947;Fjeldsa 1983;Grant 1986), marsupials (Jones 1997), carnivores (Dayan et al 1992), and shrews (Malmquist 1985). Surprisingly, few studies (e.g., Patterson 1981;Alcántara 1991;Yom-Tov 1991;Yom-Tov et al 1999) have been devoted to rodents, although interspecific competition has been repeatedly demonstrated in this group (Schoener 1983;Abramsky 1984;Dueser et al 1989).…”

“…Their ecology has been extensively studied (cf. Jüdes 1982;Montgomery 1989a;Wilson et al 1993) and obviously can serve as a proper model for testing character displacement and (or) release (Alcántara 1991;cf. Dayan and Simberloff 1998).…”

Latitudinal Geographical Variation of External and Cranial Measurements inApodemus peninsulae,A. draco, andA. latronum

“…Latitudinal body size changes have been set forth in five species of Apodemus in relation to Bergmann's rule or the reverse of Bergmann's rule. Apodemus flavicollis obeys Bergmann's rule (Niethammer 1969(Niethammer , 1978aAlcántara 1991), whereas three species of Apodemus follow the reverse of Bergmann's rule: A. sylvaticus (Niethammer 1969(Niethammer , 1978bAlcántara 1991;Renaud and Michaux 2007), A. chevrieri (Li et al 2008), and A. agrarius (Hille and Meinig 1996;Koh et al 1998). Apodemus mystacinus conforms to Bergmann's rule (Tchernov 1979) or the reverse of Bergmann's rule (Yom-Tov and Geffen 2006).…”

“…The term "character displacement" was originally given by Brown and Wilson (1956) as for competition between the two species, and later it was redefined by Grant (1972) as the process by which a morphological character state of a species changes under natural selection arising from the presence of one or more ecologically and/or reproductively similar species in the same environment. Bergmann's rule disclosed in A. flavicollis and the reverse of Bergmann's rule exhibited in A. sylvaticus were explained by character displacement (Niethammer 1969;Alcántara 1991), because their geographical ranges are overlapped in Europe (Corbet 1966;Panteleyev 1998).…”