159.

Lusitanian Pine Vole

Microtus lusitanicus

French: Campagnol basque / German: Iberien-Wiihimaus / Spanish: Topillo lusitano

Taxonomy. Arvicola (Microtus) lusitanicus Gerbe, 1879, Portugal.

Microtus lusitanicus is in subgenus Terricola and duodecimcostatus species group. It is a sister species to M. duodecimcostatus . It was classified in genus Pitymys . Two subspecies recognized.

Subspecies and Distribution.

M.l.lusitanicusGerbe,1879—regionsofPortugalandSpainthatareundertheinfluenceofMediterraneanclimate.

M. l. mariae Forsyth Major, 1905 — humid parts N of the range in SW France and N Spain.

Descriptive notes. Head—body 80-94 mm,tail 23-31 mm; weight 14-23 ¢. The Lusitanian Pine Vole is small, with short tail. Although closely related to the Mediterranean Pine Vole ( M. duodecimcostatus), the Lusitanian Pine Vole is more gracile and less fossorial. Females have two pairs of inguinal nipples. Dorsal fur is dark brown, and belly is gray. Skull is lightly built, with moderately expanded zygomatic arches and wide interorbital region. Alveolar process is weak. Upper incisors are only slightly proodont. Enamel pattern is similar to the Mediterranean Pine Vole.

Habitat. Wide variety of habitats such as meadows, pastures, oak and chestnut woods, shrubs, and agricultural areas from sea level to elevations of ¢.2000 m. The Lusitanian Pine Vole finds optimal habitat in fine-scale mosaic of vineyards, olive groves, and crop fields. Compared with the Mediterranean Pine Vole, the Lusitanian Pine Vole prefers higher elevation sites, with higher cover of shrubs, soil with lower clay content, and less shade of tree canopy.

Food and Feeding. Leaves and stems are staple foods of the Lusitanian Pine Vole during the growing season in winter and spring. During the rest of the year,it feeds on tubers, roots, and bulbs of various geophytes, and seeds of grasses (e.g. animated oat, Avena sterilis, Poaceae). Important dietary plants are buttercup oxalis ( Oxalis pes-caprae, Oxalidaceae); sedge ( Cyperus, Cyperaceae); annual bluegrass ( Poa annua), goatgrass ( Aegilops), and couch grass ( Cynodon dactylon), all Poaceae; common beet ( Beta vulgaris, Amaranthaceae); and blue clover ( Medicago nigra), lupine ( Lupinus), and clover ( Trifolium), all Fabaceae . At high densities (up to 300 ind/ha), Lusitanian Pine Voles can damage orchards and vegetable crops such as carrot and potatoes.

Breeding. Under favorable conditions, Lusitanian Pine Voles are reproductively active throughout the year, but breeding season can be interrupted by summer drought. Gestation lasts 22-24 days, and females have 1-5 embryos, most often 2-3 (mean 2-3). Litters in captivity have 1-3 young (mean 2). Newborns weigh 1-5-1-6 g, are blind and hairless, and have closed ears. Ears open at 4 days old, and eyes open at 12-13 days old. Hair starts growing at 6 days old,fur is fully developed at 13-14 days old, and individuals molt into adult pelage at 25-70 days old. Adult weight is achieved at ¢.40 days old.

Females mature at 35 days old and males at 50 days old. Captive females have litters every 28 days and display postpartum estrus.

Activity patterns. The Lusitanian Pine Vole is active throughout the day, frequently alternating one hour periods of activity with three hours of inactivity. Although less fossorial than the Mediterranean Pine Vole, the Lusitanian Pine Vole also excavates extensive burrow systems with forefeet and teeth. Galleries are 15 cm deep, but nest chamber and caches are deeper, up to 40 cm. Where dense vegetation provides sufficient cover, or if soil is too hard to dig, Lusitanian Pine Voles are active aboveground and hide nests in plant clumps or under rocks.

Movements, Home range and Social organization. In central Portugal, home ranges of Lusitanian Pine Voles are 1042 m® for males and 862 m?* for females. Distance between two most remote points of a home range averages 65-3 m. Mean intersexual overlap of home ranges is 75-5%, and overlap between female ranges averages 58-7%. Largest daily movements were recorded for sexually mature males, and mean speed was 72-8 m/ day . Lusitanian Pine Voles have a monogamous mating system. Basic social unitis a breeding pair and its offspring. Adults frequently share the same nest.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Lusitanian Pine Vole is abundant throughoutits distribution and locally controlled as an agricultural pest.

Bibliography. Bastos-Silveira et al. (2012), Niethammer (1982g), Mira & Mathias (2002), Santos, Lourenco et al. (2010), Santos, Mathias & Mira (2010, 2011).