Question 90 from UPSC CSE 2024 - Environm ent

Question

Consider the following:
1. Carabid beetles
2. Centipedes
3. Flies
4. Termites
5. Wasps
Parasitoid species are found in how many of the above kinds of organisms?

IASCODEX · Accepted Answer

Correct Option: B. Only three

Strategy: Evaluate which taxa are evolutionarily known for parasitoidism. Parasitoids mainly occur among some beetles, flies, and wasps. Centipedes are strictly predators, not parasitoids; termites are detritivores or herbivores, not hosts for parasitoids. Careful recall excludes centipedes and termites, confirming only three categories have parasitoid species.

Key Info: A parasitoid is an organism, typically an insect, that spends a substantial portion of its life attached to or within a single host organism, ultimately killing the host. This is distinct from typical parasites (which rarely kill the host) and approaches predation in ecological outcomes.

- **Carabid beetles:** The Carabidae family contains a few genera with parasitoid larvae, for example, Brachinus and Lebia. The parasitoid habit is rare in beetles overall, but present in select carabids, which often attack the egg cases or larvae of other insects.
- **Centipedes:** These arthropods are fast, venomous predators targeting invertebrates like worms, insects, and spiders. They are not parasitoids and do not use other organisms' bodies as developmental hosts.
- **Flies:** Many species in the order Diptera (notably the Tachinidae and some other families) are parasitoids. Their larvae develop inside hosts such as caterpillars or beetle larvae, eventually killing them. Dipteran parasitoids are of great agricultural and ecological importance for biological control.
- **Termites:** Order Blattodea, termites are social insects involved in decomposing dead plant material. They are neither predators nor parasitoids and generally are not themselves targets of known parasitoid lifecycles.
- **Wasps:** Hymenoptera, especially superfamilies Ichneumonoidea and Chalcidoidea, are the most speciose group of parasitoids. Many wasp species lay eggs in or on host insects or spiders, their larvae consuming and ultimately killing the host. Their diversity makes them critical agents for natural and applied biological control.

Parasitoidism is a major evolutionary strategy, especially widespread in the Hymenoptera and Diptera, and only sporadically present in some beetle taxa.

IASCODEX · Answer

Option A: Only two

IASCODEX · Answer

Option C: Only four

IASCODEX · Answer

Option D: All five

Consider the following: Carabid beetles Centipedes Flies Termites Wasps Parasitoid species are found in how many of the above kinds of organisms?

Consider the following:

Carabid beetles

Centipedes

Flies

Termites

Wasps
Parasitoid species are found in how many of the above kinds of organisms?