Q70. Protists belonging to the genus Trichonympha thrive in the gut of termites.
They help the termites use wood as a food source. This relationship is an
example of
(A) parasitism.
(B) competition.
(C) commensalism.
(D) mutualism.
The relationship between Trichonympha protists and termites is mutualism. Trichonympha, a genus of parabasalid protists, lives in the hindgut of lower termites and digests cellulose from wood, enabling termites to use it as food. Both organisms benefit: protists get shelter and nutrients, while termites gain essential digestion aid.
Option Analysis
(A) Parasitism involves one organism benefiting at the expense of the other, often harming the host. This does not apply, as Trichonympha provides vital cellulose digestion without harming termites.
(B) Competition occurs when organisms vie for the same resources, reducing fitness for both. Termites and Trichonympha do not compete; they cooperate for wood breakdown.
(C) Commensalism means one benefits while the other remains unaffected. Here, both gain advantages, ruling this out.
(D) Mutualism fits perfectly, as Trichonympha breaks down lignocellulose into usable acetate for termites, receiving a stable anaerobic habitat and food supply in return.
Trichonympha protists in the termite gut exemplify Trichonympha termites gut mutualism, a key symbiosis topic for CSIR NET Life Sciences. These anaerobic flagellates thrive in lower termites’ hindgut, breaking down cellulose that termites cannot digest alone.
Role of Trichonympha
Trichonympha ingests wood particles and uses enzymes to convert cellulose into sugars, then acetate—the termite’s primary energy source. Termites provide an anoxic environment, constant wood supply, and protection via proctodeal trophallaxis after molting. Thousands of flagella help Trichonympha maintain position in the gut flow.
Why Mutualism?
In mutualism, both partners benefit equally. Termites survive on wood diet; protists get nutrients and habitat. This contrasts with ancestral possibly parasitic stages but evolved into obligate mutualism.
Exam Relevance
For CSIR NET, distinguish symbiosis types: parasitism harms host; competition shares resources harmfully; commensalism one-sided benefit. Trichonympha-termite is mutualism, often tested in ecology, microbiology sections.
