Nests and larval development of the nest building gladiator frog, Hyla faber were studied in southeastern Brazil, during the rainy season of 1988-1989. Nests were built at the pond margins, exclusively by males, and varied in shape, size, and composition in relation to the substrate. Nests were used by 1-4 individual males and housed larvae for a mean of 26 days; 0-6 egg clutches were deposited in a nest. Larvae from individual clutches stayed inside the nests for 8-38 days. Embryonic development occurred within the first 210 h after fertilization and larval development, inside an enclosure installed in a pond, lasted over 8 months. Mortality inside the nests was due to nest water evaporation and/or drainage, to eggs sinking in the first hours after fertilization, or to predation by aquatic insects. Slow larval development in Hyla faber seems to be related to breeding in permanent ponds. Nest building in Hyla faber and related species may have evolved from the habit of using natural depressions for egg laying observed in other morphologically similar species.
Marcio Martins and Célio F.B. Haddad
Vocalizations and reproductive behaviour of Hyla faber were studied for five months at Campinas, São Paulo State, Brazil. Advertisement, distress calls, and two types of territorial vocalizations of adult Hyla faber are described and figured for the first time. One of the territorial calls and the distress call were variable in pulse repetition rate, frequency and duration, and may represent graded territorial and distress communication systems. Hyla faber males built nests for egg deposition and defended territories from other males. Males called from inside the nests till a female approached. Males then left the nests and guided the females to them. Females inspected the nests before amplexus occurred. While in amplexus, females renovated the nests. Tadpoles showed gregarious behaviour inside the nest and stayed there until approximately stage 25. Parental nest guarding was not observed.
Ivan Sazima, Marcio Martins and Silvia G. Egler
José P. Pombal, Marcio Martins and Célio F.B. Haddad
Agonistic encounters and facultative parental care in Hyla faber were observed in two localities in southeastern Brazil. Maximum male density was 0.9 and 3.3 males/m2 in Campinas and Ribeirão Branco, respectively. Aggression was escalated and the highly variable aggressive calls were specific to each phase of the encounter. The last, more aggressive phases rarely occurred in Campinas; in Ribeirao Branco they occurred frequently. Male parental care (egg attendance) was common in Ribeirao Branco while it was never observed in Campinas. Egg attendance lasted one to two nights and was observed only during high male density. The main benefit of egg attendance seemed to be avoiding nest intrusion by other males (sunken eggs and/or embryos invariably die). Males may build additional nests during egg attendance, but attending males did not attract females (they did not call).
Izeni Pires Farias, Afrânio Melo, Marcio Martins, Adriano Jerozolimski, Maria das Neves Viana and Luis Alberto dos Santos Monjeló
We conducted a population genetic analysis of the two Amazonian tortoises, Chelonoidis denticulata (n = 40) and Chelonoidis carbonaria (n = 39) in a region of sympatry within the Xingú River basin. High levels of gene flow among sampled localities indicated lack of population structure for both species. Genetic parameters indicated a moderate level of genetic diversity in C. denticulata and neutrality tests suggested that populations of this species were in demographic equilibrium with respect to mitochondrial DNA. On the other hand, C. carbonaria presented low levels of genetic diversity and a signal of population expansion. Most records of C. denticulata are from areas of humid forest while those for C. carbonaria are from areas of semi-deciduous forests and transitional areas between humid and semi-deciduous forests. Therefore, the demographic expansion observed in C. carbonaria population could reflect an increase in the availability of suitable habitats for this species due to anthropogenic or natural processes. Additionally, we observed haplotype sharing between these two tortoise species indicating hybridization or incomplete lineage sorting.