Commensalism in Gros Morne

Newfoundland and Labrador’s provincial flower is undoubtedly an intriguing organism, as well as a strikingly relevant one to our work on the BIObus. The flower, Sarrencia purpurea, commonly known as the purple pitcher plant, is immediately striking to the eye when encountered. What catches one’s attention is not necessarily the flower itself, but the peculiarly shaped leaf structures surrounding the base – this is where the purple pitcher plant hosts a unique microcosm of life and receives much of its nutrients. The leaves form a pitcher that collects water wherein various prey items land, get caught, and are processed by a host of microorganisms, enzymes, and very specific insect larva, leading to the ‘carnivorous’ plant categorization enjoyed by Sarrencia purpurea. While the pitcher plant hosts digestive enzymes of its own, the majority of the breaking down of food for nutrient acquisition is done by the organisms hosted within which form the inquiline food web.

This is the flower of an individual Sarrencia purpurea that we found at the Berry Hill peat bog collection site in Gros Morne National Park.
This is the flower of an individual Sarrencia purpurea that we found at the Berry Hill peat bog collection site in Gros Morne National Park.

Alas, our focus on the BIObus this summer is not flowers but insects. Within the ecosystem hosted by the purple pitcher plant’s leaves are often dipteran larvae that hold a commensal relationship with the flower. This dipteran is the mosquito Wyeomyia smithii. Wyeomyia smithii is not a true insectivore in its larval form; while it feeds on the deteriorating pieces of insects caught in the leaves, it also feeds on the population of rotifers, protozoans, midges and bacteria that dwell within the miniature ecosystem. It is considered a keystone predatory species due to its massive impact on the ecosystem that hosts it, as Wyeomyia smithii affects the balance of every other species within based on its presence alone.

The unique pitchers that the leaves form on the pitcher plant.
The unique pitchers that the leaves form on the pitcher plant.

The geographic range of this mosquito is intrinsically dependent on the range of Sarrencia purpurea, the most broadly distributed pitcher plant currently known. The range extends across nearly the entire eastern seaboard of the United States and extends over much of Southern and Eastern Canada.

The mosquito’s eggs hatch within the pitcher plant’s phytotelmata (the aqueous solution hosted within the leaves) and proceed to develop for approximately 22 days before they emerge to adulthood. The adult form is not the typical pest mosquito you may be accustomed with, as it feeds primarily on nectar, so you won’t be finding it mentioned within the must-read “Best of the biters” post authored by Jill. Once an adult, the mosquito lives for roughly 40 days where it will feed, reproduce, and lay eggs within Newfoundland and Labrador’s provincial flower, and hopefully experience true insect love along the way.

-Forest

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