Frog eggs : unique food source for leech Bassianobdella fusca

Bassianobdella fusca, which is common throughout much of Eastern Australia, has been reported to rely on blood as a means of procuring nourishment and is generally considered to be a parasite of adult amphibians, fish and invertebrates. A related species has become an economic pest in the earthworm industry. During an extended study of a frog assemblage in Western Sydney, we did not observe B. fusca to parasitise adult frogs but they were a predator of Limnodynastes tasmaniensis eggs, although they were not found to parasitise any other local species including sympatric species of the genus. We observed that eggs are only vulnerable to ingestion for 24 hours after oviposition. Based on estimates of ingestion rates, at naturally densities B. fusca could potentially consume the whole of the clutch during some reproductive bouts.