Microgeographic genetic structure of Oligoryzomys longicaudatus (Rodentia, Cricetidae) in periods of different population density

ORTIZ, N.; JUAN, E.E.; CHIAPPERO, M.B.; GARDENAL, C.N.; PROVENSAL, M. C.; POLOP, J.J.; GONZÁLEZ ITTIG, R.E.

JOURNAL OF MAMMALOGY

ALLIANCE COMMUNICATIONS GROUP DIVISION ALLEN PRESS

Lugar: Lawrence; Año: 2019

0022-2372

The long-tailed pygmy rice rat Oligoryzomys longicaudatus (Rodentia, Cricetidae)experiences marked population density fluctuations. This species is the major reservoirof the Andes orthohantavirus associated with the hantavirus pulmonary syndrome insouthern Argentina, and information on dispersal patterns at different populationdensities, or differences in dispersal between the sexes during those periods, couldcontribute to understanding risk of viral transmission among individuals. We examinedthe spatial genetic structure of O. longicaudatus at a local scale to elucidate howvariation in population density influences dispersal patterns. Effective dispersal levelswere estimated through spatial genetic autocorrelation (SGA) analyses in periods ofdifferent density, and for females and males separately, within an area of 510 x 180 m,using seven microsatellite loci. In autumn (high-intermediate and intermediatedensities), SGA was primarily determined by females, which show philopatric behaviorin defense of their nests and newborns. In summer (low density), neither sex showedSGA, which could be due to spacing behavior combined with high recruitment ratesamong adjacent environments. At high-intermediate densities, females remained closeto each other, contracting their home ranges. These established individuals would?fence? the area, preventing the immigration of individuals from proximate areas, untilpopulation density declines again. We detected differential patterns of effectivedispersal for both sexes in different stages of the annual and inter-annual populationphases of O. longicaudatus. Since high levels of gene flow were reported for both sexesin summer and for males in all analyzed seasons, the transmission risk of diseases suchas hantavirus pulmonary syndrome would be high at a local scale