During a general fruiting season in the mixed dipterocarp forests of Southeast Asia, some frugivore species show a conspicuous immigration and population eruption despite its aseasonal climate. However, the mechanism of the migration and population eruption was not yet known. Therefore, we monitored the populations of middle to large ground dwelling vertebrates at a large spatial scale in Deramakot and Tangkulap FR in Sabah, Malaysia. We set 87 automatic remote cameras in the 827km2 area.

General fruiting occurred at the beginning of a preliminary survey (Sep-Nov, 2007), but did not occur during the main study period (May 2008-Dec 2009). Of the 38 species of mammals and bird monitored, only Bearded pig showed an obvious population fluctuation following the general fruiting. The trapping ratio during general fruiting season increased by 10 times than during a normal season. During a normal season, no area showed a significantly high trapping ratio of Bearded pig. Because previous studies and hunting records suggested that population eruption was only obvious when general fruiting occurred twice in the same year or consecutive two years, the population eruption may be caused by the repression of death ratio of newborn infants during the general fruiting.