The Tradescants' Orchard

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Data from: Complex inter-kingdom interactions: carnivorous plants affect growth of an aquatic vertebrate

1. Coexistence of organisms in nature is more likely when phenotypic similarities of individuals are reduced. Despite the lack of similarity, distantly related taxa still compete intensely for shared resources. No larger difference between organisms that share a common prey could exist than between carnivorous plants and animals. However, few studies have considered inter-Kingdom competition among carnivorous plants and animals. 2. In order to evaluate interactions between a carnivorous plant (greater bladderwort, EUtricularia vulgaris) and a vertebrate (bluegill%, Lepomis macrochirus) on a shared prey (zooplankton), we conducted a mesocosm experiment. We deployed two levels of bladderwort presence (functional and crushed) and measured bluegill responses (survival and growth). 3. Zooplankton abundance was reduced the greatest in bluegill and functional bladderworts treatments. Bluegill survival did not differ among treatments, but growth was greatest with crushed bladderwort. Thus bluegill growth was facilitated by reducing interference competition in the presence of crushed bladderwort. The facilitating effect was dampened, however, when functional bladderwort removed a shared prey. 4.To our knowledge, this is one of the first studies to experimentally demonstrate interactions between a carnivorous plant and a fish. Our data suggests that carnivorous plants may actively promote or reduce animal co-occurrence from some ecosystems via facilitation or competition

Harmless nectar source or deadly trap: Nepenthes pitchers are activated by rain, condensation and nectar

The leaves of Nepenthes pitcher plants are specialized pitfall traps which capture and digest arthropod prey. In many species, insects become trapped by ‘aquaplaning’ on the wet pitcher rim (peristome). Here we investigate the ecological implications of this capture mechanism in Nepenthes rafflesiana var. typica. We combine meteorological data and continuous field measurements of peristome wetness using electrical conductance with experimental assessments of the pitchers' capture efficiency. Our results demonstrate that pitchers can be highly effective traps with capture rates as high as 80% but completely ineffective at other times. These dramatic changes are due to the wetting condition of the peristome. Variation of peristome wetness and capture efficiency was perfectly synchronous, and caused by rain, condensation and nectar secreted from peristome nectaries. The presence of nectar on the peristome increased surface wetness mainly indirectly by its hygroscopic properties. Experiments confirmed that pitchers with removed peristome nectaries remained generally drier and captured prey less efficiently than untreated controls. This role of nectar in prey capture represents a novel function of plant nectar. We propose that the intermittent and unpredictable activation of Nepenthes pitcher traps facilitates ant recruitment and constitutes a strategy to maximize prey capture