Changing sex-biased dispersal in Calomys venustus (Rodentia: Sigmodontinae) along linear habitat during the breeding season.

CHIAPPERO MARINA; SOMMARO LUCÍA; PRIOTTO JOSÉ; STEINMANN AANDREA; GARDENAL CRISTINA

Mendoza

Congreso; The 10 th International Mammalogical Congress; 2009

&amp;lt;!-- /* Font Definitions */ @font-face {font-family:Helvetica-Narrow; panose-1:0 0 0 0 0 0 0 0 0 0; mso-font-alt:"Arial Narrow"; mso-font-charset:0; mso-generic-font-family:swiss; mso-font-format:other; mso-font-pitch:auto; mso-font-signature:3 0 0 0 1 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:595.3pt 841.9pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:35.4pt; mso-footer-margin:35.4pt; mso-paper-source:0;} div.Section1 {page:Section1;} --&amp;gt; The landscape pattern of central Argentinean plains consists almost exclusively of agricultural land separated by “border habitats”, which are narrow, linear and frequently uninterrupted for several kilometers. In order to study dispersal in those habitats, we performed spatial genetic autocorrelation (SGA) analyses by sex in C. venustus, one of the most abundant species, during the breeding season (spring, summer and autumn). Two transects with five lines of 30 georeferenced traps separated by 500m were set along opposite borders of a secondary road in an agroecosystem in central Argentina. We analyzed five microsatellite loci in 292 individuals; SGA analyses were performed using GenALEx 6.2. Both sexes showed a random pattern of genetic structure at long distances (maximum: 4000 m) during the entire breeding period, suggesting high dispersal rates along the border habitats. On the other hand, genetic structure varied seasonally at short distances. In autumn, males showed a random genetic structure, while females showed positive autocorrelation until 215 m. This result was similar to the pattern found in summer, but positive autocorrelation in females was observed at shorter distances (172 m). In spring, the pattern was the opposite: genetic structure of females was random while males showed positive autocorrelation until 190 m. In this species females are the territorial sex, their distribution is determined by habitat quality, and natal dispersal occurs early (<40 days). In spring, females settle bigger habitat patches (high dispersal rates) since habitat quality quickly improves and abundance is still low. When population abundance increases (summer and autumn), juveniles tend to establish near to their mothers (Social Fence). Seasonal variations in male dispersal rates are also related to the mating system of the species.