Algae are only sucked in by accident when the
trap is stimulated by an animal (Sydenham and
Findlay 1973). This hypothesis can be clearly
denied according to our results: (1) More than
40% of the traps contained only algae and not a
single animal. (2) If algae were only trapped
together with animals, we would expect a strong
correlation between the number of algae and
animals in the trap, but this correlation is lacking.
(3) Algae are caught not only in the natural
habitat, but also under controlled conditions,
without animal presence