Brenesia 19/20: 577-589,1982 Arthropod Predators of Leptodactylid Frog Foam Nests

Several species of arthropods prey upon or utilize foam nests made by leptodactylid frogs. A spider [Lycosa pampeana) enters burrows made by Leptodactylus iatinasus in Argentina and eats most of the eggs. Two genera of dytiscid beetles have representatives that lay eggs on the foam mass Q^ Physalaemus pustulosas in Guatemala; beetle larvae hatch and swim in temporary ponds, where they feed on free-swimming tadpoles. Flies of the ephydrid Gastrops willistoni oviposit on Leptodactylus pentadactylus egg masses in Costa Rica and Brazil; maggots eat the developing embryos and may destroy the entire mass. Literature records of similar associations are reviewed. One of the most specialized aspects of ampiiibian reproduction is tine construction of foam nests by some frogs. Foam nests are built on vegetation or on the ground above water by many frogs of the families LeptodactyMdae and Rtiacophoridae {Noble, 1931 ; Porter, 1972), The foam is made by the male or female beating jelly with its limbs while in amplexus (Villa, 1972; Heyer and Rand, 1977). Once the eggs are fertilized, the egg mass is kicked vigorously by either or both parents into a froth resembling whipped meringue. This breeding pattern, independently evolved in New and Old World frogs, is advantageous to some species because: (1 ) eggs and embryos are protected against desiccation when the outher foam dries forming a water-resistant surface; (2) eggs may be laid on dry land or in pits or holes in the ground, in areas that are iikely to be flooded later; thus, embryonic development is well advanced when water becomes available; (3) eggs and embryos are not available to aquatic predators, such as fishes, leeches, ptanariae and larval arthropods, during the precarious immobile stages. Be-