Comunicaçao acústica e qíimica no reconhecimento de parceiro em cavalo-marinho Hippocampus reidi Ginsburg, 1933

Abstract

ABSTRACT - CAP 1 - Sound production is used by severa1 animal groups to provide information about an individual (i.e. a sender). However, fishes developed a myriad of sound production mechanisms, and the use of such acoustic signals has already been reported for many species within the context of mate choice, including seahorses (genus Hippocampus). The aim of this study is to verify weather females of the longsnout seahorse (Hippocampus reid) present a positive phonotaxis to the accoustical signals of an intraspecific male. We conducted playback experiments, in which two types of sound were provided to the females: a control and a stimulus. We recorded a total of 9000 seconds in the experiment, and for the analysis, we considered 7200s that females were active. The tested females did not demonstrate positive phonotaxis to the courtship click, and no playback effect was observed in the female during the time that t was into the stimulus zone (Kruskal-Wallis = 4.1272, p>0.05). Our results indicate that the acoustic signal (courtship click) alone was not enough to attract the female. We highlight the need to consider others modalities of communication in future studies, addressing the possibility ability of H. reidi to using the multimodal signalling system in the context of sexual selection.

RESUMO - CAP 2 - A sinalização química é amplamente utilizada entre os organismos, sendo considerada a modalidade mais antiga de comunicação. Sinais químicos (i.e. feromônios) são utilizados em vários contextos (e.g. atração de potenciais parceiros, demarcação de territórios, alarme, reconhecimento de grupo elou intraespecifico), podendo ser considerados como sinais que fornecem informações confiáveis sobre o emissor, refletindo com precisão a capacidadie ou recursos deste. Considerando o ambiente aquático, essa modalidade de sinalização se torna facilitada diante da solubilidade da água. Neste estudo, buscou-se verificar, em fêmeas do cavalo-marinho Hippocampus reidi Ginsburg, 1933, a capacidade de: (1) reconhecimento intraespecífico (quimiotaxia positiva); (2) reconhecimento de potenciais parceiros quando expostas apenas a sinais químicos no contexto de escolha de parceiro. Foram realizados experimento de gotejamento, constando de três baterias, com 10 repetições e duração de 900 segundos cada, onde as fêmeas focais foram expostas a feromônios. Cada bateria realizada continha um tratamento diferente, sendo eles: macho vs controle; fêmea vs controle; e, macho vs femea. Foram registrados um total de 18000s de experimento, onde 14400s foram considerados nas análises. No tratamento macho vs controle, as fêmeas permaneceram 55% do tempo associadas à zona do feromônio do macho e 45% na metade controle, demonstrando assim quimiotaxia positiva para o feromônio do macho (x2 = 79.38, df = 1, p < 0.01), enquanto que no tratamento fêmea vs controle, as fêmeas despenderam 58% do tempo associadas a zona com o estímulo de feromônio, enquanto que 42% na zona controle, também evidenciando uma quimiotaxia positiva (x2 = 79.38, df = 1, p c 0.01). Quando submetidas ao tratamento macho vs fêmea, estas despenderam 62% do tempo, de um total de 9000s, associadas à zona referente ao feromônio do macho, enquanto que 38% associadas à metade oposta onde era fornecido o feromônio da fêmea, evidenciando uma preferência pelo feromônio do macho (x2= 192.08, df = 1, p < 0.01). Os resultados mostraram que as fêmeas de H. reidi usam feromônios para localizar indivíduos da mesma espécie, bem como para discriminar entre os sexos e escolher potenciais parceiros, de forma que esses sinais químicos apresentam uma funcionalidade geral dentro do contexto de escolha de parceiro na espécie.

ABSTRACT -CAP 2 - Chemical signaling is widely used among organisms, and it is considered the oldest type of communication. Chemical signals (i.e. pheromones) are used in several contexts (e.g. attraction of potencial mate, demarcation of territories, alarm, group recognition and/or intraspecific recognition), which can be regarded as honest signals that provide reliable information about the sender, reflecting with accuracy its capacity or resources. Water solubility renders that signaling mode easier. The aim of this study was to assess, in females of the longsnout seahorse Hippocampus reidi Ginsbi~rg, 1933, the ability to: ('1 ) intraspecific recognition (positive chemiotaxis); (2) sex recognition, when exposed only to chemical cues in a mate choice context. Delivery stimulus experiments were performed, consisting of three different trials, each one with 10 repetitions and duration of 900 seconds, in which focal females were exposed to pheromones. Each trial performed contained a different treatment, as follows: male vs. control; female vs. control; and, male vs. female. A total of 18000s of experiment were recorded, of which 14400s were considered in tke analysis. In the male vs. control treatment, the females remained 55% of the time associated with male pheromone zone and 45% in the control zone, demonstrating positive chemotaxis for the male pheromone (x2 = 79.38, df = 1, p < 0.01), while in the female vs. control treatment, females spent 58% of the time associated with the pheromone zone, and 42% with the control zone, also demonstrating a positive chemotaxis (x2 = 79.38, df = 1, p < 0.01). When exposed to the male vs. female treatment, females spent 62% of the time, in a total of 9000s, associated to the zone related to male pheromone, while 38% were associated with the opposite zone, where female pheromone was provided, showing a preference for male pheromone (x2= 192.08, df = 1, p < 0.01). Our results showed that females of H. reidi use pheromones in intraspecific recognition, as well as to discriminate sex and to choose potential mate, reinforcing that these chemical cues contains a general functionality In the context of mate choice for the species.