Anfibios.

Copeia, 2005(3), pp. 642–648

Reproduction of an Introduced Population of Eleutherodactylus johnstonei at Bucaramanga, Colombia
´ JESUS EDUARDO ORTEGA, VıCTOR H. SERRANO, ´ AND

MARTHA PATRICIA RAM´REZ-PINILLA ı

Comparative ecological data on introduced populations can contribute to understanding why Eleutherodactylus johnstonei is a good invader. We studied the reproductive features ofan introduced population of this species and compared them with similar data on other introduced and native populations. Females were larger than males; sexually mature males ranged between 17–29 mm snout vent length and females between 23–32 mm. Reproductive males and females were captured throughout the year and there were no monthly significant differences in their occurrence. Clutches andneonates occurred year-round. The adjusted testicular volume did not vary significantly among months and histological analyses of the testes and ducts revealed the presence of sperm through the year, indicating continuous reproductive activity for males. The ovarian volume did not vary significantly among months and the presence of yolked follicles were observed throughout the year, indicating thatfemales also reproduce continuously. There was a positive relationship between female body size and the number of yolked follicles. Two different relationships associated with reproduction could explain sexual differences in body size; the larger body size in females allows greater clutch sizes, and the energy cost of calling activity and paternal care of the clutch limits male growth. The colonizingsuccess of E. johnstonei appears to be related to its reproductive features, such as flexibility in reproductive activity, direct development, and parental care of the clutch, allowing it to easily occupy disturbed areas that it encounters. La comparacion de los datos ecologicos de poblaciones de especies introducidas ´ ´ puede contribuir al entendimiento del por que Eleutherodactylus johnstonei esuna ´ especie invasora exitosa. Nosotros estudiamos las caracterısticas reproductivas de ´ una poblacion introducida de esta especie y las comparamos con datos similares de ´ otras poblaciones nativas e introducidas. Las hembras fueron mas grandes que los ´ machos, los machos sexualmente maduros estaban entre los 17 y 29 mm de longitud hocico cloaca y las hembras entre 23 y 32 mm. Machos y hembrasreproductivos fueron capturados a lo largo del ano y no hubo diferencias mensuales significativas ˜ en su presencia en la muestra; ası mismo, se registraron posturas y neonatos durante ´ todo el ano. El volumen testicular ajustado al tamano corporal no vario significati˜ ˜ ´ vamente entre los meses y los analisis histologicos de los testıculos y ductos mostra´ ´ ´ ron la presencia de esperma durantetodo el ano, indicando una actividad repro˜ ductiva continua para los machos. El volumen ovarico no vario significativamente ´ ´ entre meses y la presencia de folıculos yemados se observo durante todo el ano, ´ ´ ˜ indicando que las hembras tambien se reproducen continuamente. Hubo una rela´ cion positiva entre el tamano corporal de la hembra y el numero de folıculos ye´ ˜ ´ ´ mados. Dosdiferentes relaciones asociadas con la reproduccion pueden explicar las ´ diferencias sexuales en el tamano corporal; el tamano mayor de las hembras podrıa ˜ ˜ ´ permitir tamanos de postura mayores, y el costo energetico de las actividades de ˜ ´ canto y cuidado parental de la postura podrıa limitar el crecimiento de los machos. ´ El exito colonizador de E. johnstonei parece estar relacionado con suscaracterısticas ´ ´ reproductivas tales como flexibilidad en la actividad reproductiva, desarrollo directo y cuidado parental de las posturas, permitiendole facilmente ocupar las areas dis´ ´ ´ turbadas que encuentra.

LEUTHERODACTYLUS (Leptodactylidae), with almost 700 species, is the most speciose of all vertebrate genera (Lynch, pers. comm.); South America has the highest diversity of these frogs...