The Importance of the Multicomponent Display in Sexual Selection of Black Morph Girardinus metallicus (Pisces: Poeciliidae)

Multicomponent displays are composed of traits, such as coloration, structural ornaments, and behavior, that become integrated and signal information to conspecifics. Estimation of multicomponent displays in fishes often involves measurement of color traits. Fish color measurements are often obtained following immobilization via chemical anesthesia; however, the anesthetics may alter the resulting measurements, for example by darkening the skin. Girardinus metallicus, a poeciliid fish endemic to Cuba, has a multicomponent courtship and aggressive display. Black morph males exhibit black ventral coloration including the gonopodium (copulatory organ) and yellow in the non-black areas of their bodies. I investigated the effects of common anesthetics on coloration measurements of G. metallicus. I measured the hue, saturation, and brightness of the anterior dorsal, posterior dorsal, posterior ventral, and caudal body regions, from digital images of the same males obtained without using anesthetic and anesthetized using tricaine methane sulfonate (MS222) and eugenol (clove oil). Because multicomponent displays are intriguing with respect to sexual selection, I investigated the importance of size and coloration traits in sexual selection via female choice and male-male competition in G. metallicus. I found that saturation and hue did not differ significantly across treatments (anesthetization using MS222, anesthetization using clove oil, and without anesthetic in a small glass chamber containing water). However, brightness was greater under the anesthetics, possibly due to photographing the fish behind water and glass in the Non-anesthetic treatment or due to reflectivity differences of the iridophores. The body regions varied in hue, saturation, and brightness. Most importantly, I found differences in the responses of different body regions to the anesthetic treatments, suggesting that anesthetics may affect coloration in unpredictable ways, and that multiple regions of fish should be measured when assessing overall coloration. My results suggest that photographing fish in a glass chamber without anesthetic may be an effective way to obtain digital images for color analysis without using anesthetics that may influence coloration. Having determined a good method for color measurement, I then investigated the role of the multicomponent display in sexual selection. Through direct interaction tests, I found that dominant males had brighter and more saturated yellow coloration than subordinate males, and that dominant males courted more than subordinate males. Within high yellow males, dominant males attempted more copulations than subordinate males. Interestingly, low yellow, subordinate males attempted more copulations than low yellow, dominant males, suggesting that subordinate males invested time into attempting copulations rather than engaging in potentially risky aggressive behavior. I observed a greater difference in body size between the males in pairs to which I could assign dominance status than pairs to which I could not assign dominance status, suggesting the importance of standard length in aggression in this species. I found that yellow saturation may serve to signal status without the males resorting to aggressive interactions due to only half the pairs exhibiting aggression. Because aggression is key to mating success in G. metallicus, my findings that yellow coloration is correlated with aggression, in concert with previous studies showing the importance of ventral black area and body size for aggression, reinforce the idea that these males exhibit a multicomponent signal to conspecifics in the context of sexual selection

Effects of dietary antioxidant of tomato extract and lycopene on Carassius auratus and Xiphophorus maculatus

Objective. Evaluate the effect on tegument pigmentation, survival, growth and antioxidant capacity in diets supplemented with tomato extract and lycopene as additives in experimental feed for Carassius auratus and Xiphophorus maculatus. Materials and methods. The additives were added in different concentrations to a basic diet. We performed beginning and an ending biometrics for 100% of the population in each bioassay. The growth and survival of organisms were evaluated. The antioxidant capacity was analyzed by ABTS assay, both in the tomato extract sample as well as in foods used in different bioassays. The concentration of lycopene was determined in food and liver and muscle samples of fish fed with it. Acquired pigmentation of fish was assessed through photographs analyzed with Adobe Photoshop®. The results were evaluated by analysis of variance, and when differences were found (p<0.05) the means were compared by the Tukey test. Results. No significant effect (p>0.05) on pigmentation and growth of the organisms under the established experimental conditions was obtained. Significant differences in antioxidant capacity (p<0.05) were obtained in foods with added lycopene. Conclusions. The inclusion of lycopene or tomato extract in food for the organisms used is not recommended to improve pigmentation, but further studies are needed to demonstrate antioxidant effect

Evaluación de la diversidad ictiológica del lago Yahuarcocha, provincia de Imbabura

Evaluar la diversidad y abundancia ictiofaunística del lago Yahuarcocha, provincia de Imbabura.El lago Yahuarcocha es un ecosistema lacustre de gran importancia ambiental y socioeconómica para la provincia de Imbabura, debido a los servicios ecosistémicos que brinda para el uso de materias primas y el desarrollo de actividades recreativas y turísticas. Sin embargo, se ha deteriorado el estado del ecosistema acuático debido a las perturbaciones ambientales, como es la introducción de especies ícticas las cuales afectan la cadena alimenticia, ya que, no disponen de un controlador biológico. Por consiguiente, el objetivo de la presente investigación fue evaluar la diversidad y abundancia ictiofaunística del lago Yahuarcocha, en donde se aplicaron encuestas, se realizaron diversos muestreos en seis sitios para caracterizar a los peces, detallando el nombre de la especie, sexo, estadio y los parámetros físico-químicos, así como también se emplearon índices de diversidad y se elaboró una guía de identificación. En total se encontraron cuatro especies: Poecilia reticulata, Xiphophorus hellerii, Carassius auratus y Oreochromis niloticus en concordancia con los encuestados, el porcentaje de hembras fue mayor que el de los machos e indeterminados, igualmente el porcentaje de adultos fue mayor que el de los juveniles y los valores de parámetros ambientales fueron bajos en oxígeno disuelto y transparencia, altos en conductividad y el pH fue alcalino. La diversidad de especies fue muy baja y se registró una alta abundancia de P. reticulata, adicionalmente en la guía se proporcionó ilustraciones e información sistemática sobre las especies. En definitiva, la información generada a partir del estudio permitirá realizar nuevas investigaciones y proyectos para el manejo adecuado de estas especies introducidas.Ingenierí

Effects of dietary antioxidant of tomato extract and lycopene on Carassius auratus and Xiphophorus maculatus [Efecto antioxidante de un extracto de jitomate y licopeno en Carassius auratus y Xiphophorus maculatus]

Objective. Evaluate the effect on tegument pigmentation, survival, growth and antioxidant capacity in diets supplemented with tomato extract and lycopene as additives in experimental feed for Carassius auratus and Xiphophorus maculatus. Materials and methods. The additives were added in different concentrations to a basic diet. We performed beginning and an ending biometrics for 100% of the population in each bioassay. The growth and survival of organisms were evaluated. The antioxidant capacity was analyzed by ABTS assay, both in the tomato extract sample as well as in foods used in different bioassays. The concentration of lycopene was determined in food and liver and muscle samples of fish fed with it. Acquired pigmentation of fish was assessed through photographs analyzed with Adobe PhotoshopZapotitlán. The results were evaluated by analysis of variance, and when differences were found (p0.05) on pigmentation and growth of the organisms under the established experimental conditions was obtained. Significant differences in antioxidant capacity (p<0.05) were obtained in foods with added lycopene. Conclusions. The inclusion of lycopene or tomato extract in food for the organisms used is not recommended to improve pigmentation, but further studies are needed to demonstrate antioxidant effect

Effects of dietary antioxidant of tomato extract and lycopene on Carassius auratus and Xiphophorus maculatus [Efecto antioxidante de un extracto de jitomate y licopeno en Carassius auratus y Xiphophorus maculatus]

Objective. Evaluate the effect on tegument pigmentation, survival, growth and antioxidant capacity in diets supplemented with tomato extract and lycopene as additives in experimental feed for Carassius auratus and Xiphophorus maculatus. Materials and methods. The additives were added in different concentrations to a basic diet. We performed beginning and an ending biometrics for 100% of the population in each bioassay. The growth and survival of organisms were evaluated. The antioxidant capacity was analyzed by ABTS assay, both in the tomato extract sample as well as in foods used in different bioassays. The concentration of lycopene was determined in food and liver and muscle samples of fish fed with it. Acquired pigmentation of fish was assessed through photographs analyzed with Adobe Photoshop®. The results were evaluated by analysis of variance, and when differences were found (p0.05) on pigmentation and growth of the organisms under the established experimental conditions was obtained. Significant differences in antioxidant capacity (p<0.05) were obtained in foods with added lycopene. Conclusions. The inclusion of lycopene or tomato extract in food for the organisms used is not recommended to improve pigmentation, but further studies are needed to demonstrate antioxidant effect