Predation on foam nests of leptodactyline frogs (Anura: Leptodactylidae) by larvae of Beckeriella niger (Diptera: Ephydridae)

Abstract

The presence of maggots of the fly Beckeriella niger (Ephydridae) in nests of six syntopic South American leptodactyline frogs is reported. The number of tadpoles of Physalaemus cuvieri leaving infested and non-infested nests were compared, and behavioural plasticity at the time of nest departure in the presence and absence of maggots was tested for. Maggots were found in nests of all species with exposed foam nests (four Physalaemus and two Leptodactylus species). The maggots remained in the nests of P. cuvieri for up to 3 days; adults emerged from pupae after 7 days. While in the nests the maggots consumed eggs, embryos, and tadpoles. The levels of infestation increased from the beginning to the middle of the rainy season. Mortality caused by the maggots represented an important source of mortality (mean 74%) of eggs and embryos of P. cuvieri, and probably, of the other species. The time of emergence from nests by the tadpoles of P. cuvieri was shorter (up to 21 h earlier) in infested nests. The tadpoles that left the infested nests were at the same, or a less-developed stage than tadpoles in non-infested nests. The variation in the degree of infestation, with lower values at the beginning and the increase to the middle of the rainy season, suggests that the flies may be an obligatory predator on foam nests. For tadpoles of P. cuvieri, entering the water at a later developmental stage may be important to avoid aquatic predators. Conversely, leaving infested nests at the earliest possible stage may represent a strategy to avoid maggot predation. The longer time before emergence of tadpoles of P. cuvieri from non-infested nests corroborates the hypothesis that, among leptodactyline frogs, the foam nest is a predator avoidance adaptation in the aquatic media.

Species composition and reproductive modes of anurans from a transitional Amazonian forest, Brazil

“…Regardless of the type of larval development, this characteristic can be considered a first step towards a more terrestrial mode of reproduction. The foam has a number of functions that are essential in this type of habitat, such as protection against predators (DOWNIE 1990, MENIN & GIARETTA 2003, protection from dehydration (HEYER 1969, MAGNUSSON & HERO 1991), maintenance of the oxygen level appropriate for the eggs (SEYMOUR & LOVERIDGE 1994), and temperature control (DOBKIN & GETTINGER 1985), as well as providing a source of food for the tadpoles of some species (TANAKA & NISHIHARA 1987). Furthermore, species in the Leptodactylus pentadactylus group, such as L. labyrinthicus, exhibit extra strategies that guarantee larval survival in unpredictable habitats, such as trophic eggs to feed the larvae (e.g.…”

Building a home from foam—túngara frog foam nest architecture and three-phase construction process

“…Colonial nests may be more attractive to specialist nest parasites such as frog flies (Downie et al 1995;Vonesh 2000;Menin & Giaretta 2003;Giaretta & Menin 2004) because such nests are probably easier to locate, and infestation of one nest could permit access to all. Advantages to the frogs may include a …”

Morphological Diversity and Evolution of Egg and Clutch Structure in Amphibians

“…Such nests are produced by certain hylids (Haddad et al, 1990), hyperoliids (Amiet, 1974), leptodactylids (e.g., Hö dl, 1990;Schlü ter, 1990;Shepard and Caldwell, 2005), limnodynastids (e.g., Littlejohn, 1963;Tyler and Davies, 1979), microhylids (e.g., Glaw and Vences, 1992;Haddad and Hö dl, 1997), and rhacophorids (e.g., Coe, 1974;Fukuyama, 1991;Liu, 1950); and see Duellman and Trueb (1986). Suggested functions for froth nests include: escape from the aquatic environment (Heyer, 1969), protection of eggs and embryos from desiccation and thermal damage (Gorzula, 1977;Heyer, 1969;Hö dl, 1986), floatation for aquatic eggs (Haddad and Hö dl, 1997), protection from aquatic predators and cannibals (Hö dl, 1990; but see Altig, 1996 andMenin andGiaretta, 2003), and enhanced oxygenation of the eggs and embryos either from being held near the meniscus (Haddad and Hö dl, 1997) or from the air trapped in the bubbles per se. There are two types of froth nests: foam and bubble.…”