Aquatic phytotelmata, such as those formed by pitcher plants or bromeliads, turned out to be great model systems in a tropical climate and were used to test numerous ecological hypotheses, such as metapopulation and metacommunity dynamics, island biogeography or food web interactions. In Europe, only a small number of plant species exhibit morphological structures that would be able to hold water long enough to provide suitable conditions for the development of aquatic communities, teasels (Dipsacus fullonum) being one of them. The teasel plant is a biennial herb, evolved clasping leaf bases forming cup-like tanks, which are usually filled with rainwater and detritus, leading to the creation of a simple aquatic community. Although teasels lack typical ecological or life history traits of true carnivorous species, they were assumed to catch invertebrates in their leaf-base tanks and there has been a long-lasting debate about them benefitting from carnivory.
We tried to assess the role of organic matter in the diversity of aquatic communities in phytotelmata and the fitness of the whole teasel plants. We have conducted large-scale monitoring of phytotelmata of teasel plants and a longitudinal experiment on three sites in Slovakia. The quality and quantity of organic matter in phytotelmata were manipulated experimentally in order to verify the carnivory hypotheses.
The most common invertebrates inhabiting teasel phytotelmata were chironomids Metriocnemus eurynotus (Diptera, Chironomidae) and biting midges from genus Dasyhelea (Diptera, Ceratopogonidae), while these two groups partitioned the temporal niche. We have not confirmed that teasel plants do profit from animal-based detritus, which contradicts the carnivory hypothesis. On the other hand, experimental plants with added plant-based detritus showed significantly heavier seeds than control plants and plants with animal-based detritus meaning that the teasels benefit rather from plant remains than the passive carnivory.
This study was supported by project VEGA no.1/0012/20.