Phyllotis andium

Abstract: We provide the first detailed description of the diet of Burrowing Owls ( Athene cunicularia ) for Ecuador, based on an analysis of 408 pellets collected from one locality in the north and one in the south of the central dry Andean Valley. Our results are consistent with previous studies in the Neotropics that document the importance of insects in the diet. Rodents made up 78.8% of the biomass in our sample. Additionally, we highlight the first record of the Andean eared mouse Phyllotis andium in a xeric environment, which was identified in the pellets.

Abstract: The Andean Leaf-eared mouse, Phyllotis andium Thomas 1912, has been considered a widespread medium-size sigmodontine rodent (230 mm of total length and 35 grams approximately) that occurs from Tungurahua, Ecuador, through the Andes, to Lima, Peru. Previous studies performed on Phyllotis noted evidence of morphological geographical variation within the species, which is likely because of the several potential geographical barriers that exist within the distribution range of P. andium. We carried out a taxonomic revision of this species based on qualitative and quantitative morphological analyses of 330 specimens from 92 localities. This included appropriate comparisons with other species of the andium/amicus group and performed molecular analysis based on cytochrome b sequences. As a result, morphologic qualitative analysis suggested the recognition of three different taxa, which are supported by morphologic quantitative and molecular analyses. The three taxa here identified have allopatric distributional ranges separated by important geographic barriers. Following these identification criteria, P. andium is now recognized for the samples from Tungurahua, Ecuador to Huanuco, Peru, and includes melanius and fruticicolus as synonymous; the southern populations from the Ancash and Lima departments, in the western Peruvian Andes, are proposed to represent a new species; and we recognize P. stenops as a valid species with tamborum as a synonym. Finally, we postulate that the diversification of these three species is related to key events in the Andean orogeny.

Abstract: An albino specimen of Phyllotis andium Thomas, 1912 was live-trapped in Lomas de Lachay (11° 21’ 03” S, 77° 21’ 11” W), central coast of Peru, a locality where the authors have been studying population dynamics and the assemblage of trophic cascades within the vertebrate community, from 1998 until 2003. It was a juvenile male weighing 15 g with snow-white fur and pink eyes. Details about the study area, reproduction and population density of this species have been previously reported (Arana et al., 2002). Besides, a pair of wild-type P. andium, born in captivity and direct descendants of animals collected two years before in the same locality, had a litter of three pups, where one of them was an albino female, proving that both specimens were heterozygotes for the albino allele. The albino specimen collected in Lachay was crossed two consecutive times with the heterozygote female (wild-type that previously was the mother of one female albino). The first litter was constituted both by one albino and one wild-type specimen, while the second litter was constituted by one albino and two wild-type specimens. One F1 albino male was crossed with three different homozygote wildtype females and all F2 offspring had a wildtype phenotype. No codominance was observed and albino offspring were distinguished from wild-type mice on the day of birth, as found in albino meadow voles, Microtus pennsylvanicus (Brewer et al., 1993). The rareness of conspicuously colored small mammals has been generally considered as the result of a negative selection of coat color by predators (Brown, 1965; Kaufman and Wagner, 1973; Kaufman, 1974a, 1974b), though Peles et al. (1995) showed that albinism in meadow voles proved not to be a disadvantageous trait in grassland habitats of highnutritional quality and heavy vegetative cover, probably due to the relationship of high-quality habitat and avian predation. Lachay is not a high-quality habitat (those habitats dominated by plant species of high-nutritional food quality, that simultaneously provide heavy vegetative ground cover; Peles et al., 1995). It is a habitat with a strong seasonality in the vegetative ground cover with relatively few retreats for small mammals, and it is the habitat of several resident avian predators (as burrowing owls, grey eagle-buzzards, red-backed buzzard, and American kestrel) and foxes. Under these conditions, albinism is a disadvantageous trait. This is the first discovery of an albino Andean leaf-eared mouse individual in Lachay, in spite of the intense field work carried out collectALBINISM IN THE ANDEAN LEAF-EARED MOUSE, PHYLLOTIS ANDIUM (RODENTIA, CRICETIDAE)