Meeting Abstract
Aquatic environments can be dark or turbid, making visual cues difficult to detect. In these cases, chemical communication is advantageous. Poecilia latipinna, a live-bearing fish, lives in waterbodies where visual communication is not always reliable. Male P. latipinna differentiate between receptive and non-receptive females. Moreover, we have preliminary data that shows males are attracted to female extracts. In other closely related live-bearers, chemical communication is an important factor in female mate choice. We hypothesized that P. latipinna use chemical communication to coordinate mating. To investigate this, we did two experiments, observing behavior, endocrine response, and gonadal histology. In the first experiment, we paired a female with two males and recorded mating behaviors for 10 mins. We took pre- and post-mating water samples from each fish to establish a water-borne steroid profile by ELISA. Our preliminary results show complex reproductive behavior in this species, paired with a post-mating decrease of estradiol and progesterone in females; both of which are regulators of ovulation. Additionally, we found that both males and females had relatively high concentrations of glucoronidated prostaglandin F2α (474.20 ± 194.55 ng/L/h/g). Prostaglandins putatively induce ovulation in fish. Therefore, in the second experiment we quantified female physiological response to male chemical cues. We placed each female in 5 L of water, exposed them to male extracts for 4 hours and took water samples at 0h, 0.5h, 1.5h and 4h. After 4 hours, we collected ovaries for histology. We predict to see changes in water-borne steroids and gonadal composition after chemical cue exposure. This study, combined with our previous research, suggests this species uses chemical communication to coordinate mating.
