Thursday, December 9, 2010

How to Eat an Insect

A common sight on bogs and heaths throughout west Cork and Kerry, the Large Flowered Butterwort (Pinguicula grandiflora) is one of a number of carnivorous plants native to Ireland (1). On these poorer, wetter soils, carnivory offers an advantage to plants (2) and makes them indicative of such wet soils. Due to the low pH of peaty soils, nutrients become unavailable to plants as they become bound in salts. While it was previously held that the main reason for insectivorous behaviour in plants was to obtain mainly nitrogen (3), it has been shown that in a Pinguicula species, only phosphorus absorbed through the leaves leads to a significant increase in plant biomass (4).

Large Flowered Butterwort, Pinguicula grandiflora
So how does P. grandiflora capture insects to eat? The leaves of the plant carry a number of cells that are devoted to this task: secretory head cells, endodermal intervening cells and basal reservoir cells (5). The head cells hold drops of mucilaginous secretions which attract and then trap the insect prey. Further incapacitation is achieved by release of more mucilage from the reservoir cells. Digestion can then begin by the release of enzymes from the endodermal-like cells.

  1. Phillips, 1977 Wild Flowers of Britain p. 46
  2. Brewer et al., 2010 Aquatic Biology In Press, Corrected Proof
  3. Thompson, 1981 Biological Journal of the Linnean Society 16 pp. 147-155
  4. Karlsson and Carlsson, 1984 New Phytologist 97 pp. 25-30
  5. Heslop-Harrison, 1981 Annals of Botany 47 pp. 293-319

No comments:

Post a Comment