Courtship, vocalization, and tadpole description of Epipedobates flavopictus (Anura: Dendrobatidae) in southern Goiás, Brazil

Abstract

Epipedobates flavopictus is a diurnal, aposematic dendrobatid with a wide distribution in seasonal wet tropical regions of Brazil. We describe the daily period of vocalization, advertisement call, courtship behavior, and tadpole of E. flavopictus from a previously unknown population in southern Goiás and compare theses features with that of other populations. Studies were carried out in November (2004) and February (2005). We counted the number of calling males and duration of calling bouts in the morning and evening periods. The advertisement call was recorded with a digital recorder. Tadpole description was based on specimens collected in pools. Males called from well-illuminated sites such as rocky fields, rain channels, and borders of riverine forests. In November, males vocalized daily during two distinct periods, between 04:30 h and 10:00 h and between 16:30 h and 20:00 h. Morning temperature varied between 20-23ºC and humidity from 79-89%; during evening varied between 24-27ºC and 54-82%. In the middle of the day, temperature reached 36ºC and humidity 40%. During the morning, call activity was almost uninterrupted, in the evening calling bouts lasted around 9 min. In February, even with the occurrence of rainfall and temperatures similar to that of November no frog vocalized. The advertisement call is composed by a single note with 7-8 pulses with frequency ascending slightly from 3.20 to 4.05 kHz. Note duration was 144 ms, and between note intervals is 292 ms. Notes are given at a rate of 139 per minute. Upon observing the female, the male began to emit courtship call. The female approached the male and touched him laterally with her snout. The male moved forward and raised his hindquarters by stretching his hind legs. While leading the female, the male continued to give courtship and advertisement calls. The male clasped the female in axillary amplexus, and the pair entered a hole in a bank. The female deposited eggs on the surface of the soil, spreading them in groups. The egg clutches had eggs in at least two developmental stages, recently deposited and with embryos. Tadpoles were found in small, shallow rocky pools along a permanent stream, in well-illuminated sites at the forest border. The tadpole had the dorsal fin arched, not extending onto body. E. flavopictus appears to be unique among dendrobatids by using open areas subject to high temperatures and low humidity. Reproductive activity of the species ends before the end of the rainy season, possibly to avoid loss of tadpoles during months with unpredictable rainfall. The studied call had more notes and shorter between-call intervals than those described from other populations. The free-living tadpoles we describe differ from those of other populations by having the dorsal fin reduced.