As prisoners in their living habitat, parasites should be vulnerable to destruction by the predators of their hosts. But we show here that the parasitic gordian worm Paragordius tricuspidatus is able to escape not only from its insect host after ingestion by a fish or frog but also from the digestive tract of the predator. This remarkable tactic enables the worm to continue its life cycle.
A gordian worm (Paragordius tricuspidatus) leaves its cricket host (Nemobius sylvestris).
A gordian worm slides out of a frog’s mouth, the frog (Rana erythraea) having eaten the cricket in which the worm was living.
A gordian worm slides out of a trout’s gill, the trout (Oncorhynchus mykiss) having eaten the cricket in which the worm was living.