VARIATION IN GROWTH AND REPRODUCTION OF BOLOMYS LASIURUS (RODENTIA, MURIDAE) IN AN AMAZONIAN SAVANNA

Reproduction by Bolomys lasiurus is strongly seasonal in the Amazonian savanna of Alter do Chao, Para, Brazil. No pregnant or lactating fema les were recorded during the early dry season (July-September). Relati ve growth rates showed a similar though less consistent pattern. These patterns do not appear to be due to a direct effect of rainfall as hi gh reproduction and growth were recorded during the late dry season (O ctober-November), even though rainfall and the availability of fruits of shrubs were low during that period. It is likely that reinitiation of reproduction during the dry season is due to an increase in the ava ilability of invertebrates and/or wind-dispersed seeds. Fire at the en d of the dry season appears to affect the diet of the rats, causing an increase in the ingestion of invertebrates during the following wet s eason. However, our data do not indicate that fire affects individual reproductive output or growth.