LAVARIAS Sabrina Maria Luisa
Getting ready for mating: the importance of male touching as an accelerator of ovarian growth in a caridean shrimp
TROPEA, CAROLINA; LAVARIAS, SABRIA MARIA LUISA; LÓPEZ GRECO, LAURA SUSANA
Año: 2018 vol. 130 p. 57 - 66
The present study was aimed at evaluating the effect of male presence on ovarianmaturation in juvenile females and the role of potential chemical, visual and tactile cues emitted by males in that physiological process. A highly gregarious caridean shrimp with sexual dimorphism, Neocaridina davidi, was used as experimental model. We tested the hypotheses that male presence accelerate ovarian maturation, mainly through chemical cues. Two experiments were performed. In Experiment 1, juvenile females were reared with adult males, adult females or alone, allowing full contact among shrimps. In Experiment 2, these treatments were evaluated allowing chemical and visual communication, only visual communication, or only chemical communication among shrimps. In both experiments juvenile females were observed once a week under a stereomicroscope to determine ovarian growth rate. Although male presence was not necessary for ovarian maturation, it clearly accelerated the rate of ovarian growth, particularly in the last maturation phase, leading to relatively longer mature ovaries with higher lipid content. On the contrary, the presence of adult females delayed ovarian maturation in juvenile females, while females reared alone showed an intermediate ovarian growth. All these results suggest that adult males release certain cues that stimulate ovarian maturation, while adult females release cues that delay this physiological process. Neither visual cues nor chemical cues released at a distance from females were responsible, either alone or in combination, for the observed effects, since ovarian growth was only influenced when shrimps were allowed to interact freely. Male stimulatory effect may be mediated,instead, by tactile cues and/or potential short-range chemical cues released by males during their ?touching? behavior towards females. Altogether, present results partially support our initial hypotheses and contribute to increase the limited amount of information available on the role of intraspecific multimodal communication in non-behavioral reproductiveprocesses in invertebrate species.