Around the world carnivorous plants are on the decline, the victims of habitat loss, illegal poaching and pollution. But now a new factor has come to light: The very insects the plants rely on for food may be poisoning them.

According to new research by Christopher Moody and Iain Green of Bournemouth University in England, prey insects could be contaminated with toxic metals such as cadmium that, when ingested by meat-eating flora, affect the plants' growth.

Their research was published in February in the American Chemical Society journal, Environmental Science & Technology.

As part of their research, Moody and Green fed maggots that had elevated levels of cadmium and copper to endangered white-topped pitcher plants (Sarracenia leucophylla). Whereas the plants processed copper successfully, and it is in fact important to plant health, the cadmium built up in their systems, "where it was related to a reduction in shoot biomass." (In other words, the plants did not grow well when there was too much cadmium in their stems.)

Cadmium is widely used in fertilizers, metal coatings, electronics, batteries and other products. Both metals can accumulate in the environment, and thus in insects, through improper waste disposal.

Obviously, this needs further research before we can conclusively say that cadmium is killing meat-eating plants in the wild, but Moody and Green say that their findings suggest that it is important to limit the exposure of bug-scarfing plants to cadmium.

Photo: White-topped pitcher plant (Sarracenia leucophylla), via Wikipedia