Social chemosignals in five Belontiidae (Pisces) species.

Abstract

Approach behaviors toward conspecific chemical stimuli of the opposite sex were examined in 5 Belontiidae species: Betta splendens, Macropodus opercularis, Colisa labiosa, C. lalia and Trichogaster trichopterus. Approach was measured by preference for section 1 of a 3-section tank, which contained a vertical tube that introduced the stimulus water and occupancy of the tube. Experiments 1A and 1B showed that approach behaviors were displayed by the isolated male Betta only to ripe-female stimulus water, group-housed males of the remaining 4 spp. were not attracted to female-conditioned water and socially isolated males of these 4 spp. preferred section 1 during presentation of either ripe- or nonripe-female-inhabited water but occupied the tube only during exposure to ripe-female-conditioned water. The female Betta, regardless of physiological state, showed approach behaviors to male-inhabited water and only ripe females of the remaining species indicated a preference for section 1 during male-water exposure but performed no tube entries. Social isolation of the females, especially ripe females, facilitated their approach behaviors.