Question

In terms of foraging strategies, Steinernema glaseri is

• A. Ambusher
• B. Cruiser
• C. Intermediate
• D. Random

Hint:

Associate Steinernema glaseri with "white grub" control. Because white grubs live deep in the soil, they must be targeted by EPNs with active "cruiser" search behaviors.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Entomopathogenic nematodes (EPNs) use different foraging strategies to locate and parasitize insect hosts in the soil.
These strategies represent a behavioral spectrum ranging from passive, sit-and-wait behavior to active search behavior.

Step 2: Detailed Explanation:
EPN foraging behaviors are generally classified into three categories:
1. Ambushers:
Ambushers (such as Steinernema carpocapsae) use a sit-and-wait strategy.
They remain near the soil surface and often perform "nictation" behavior, where they raise their bodies vertically to attach to passing hosts.
They are highly effective against active insects on the soil surface.
2. Cruisers:
Cruisers (such as Steinernema glaseri and Heterorhabditis bacteriophora) actively move through the soil profile in search of hosts.
They are highly mobile and respond to chemical cues released by insects, such as carbon dioxide (\( \text{CO}_2 \)), excretory products, and physical vibrations.
This makes them effective against sedentary or subterranean insect hosts, such as white grubs (scarab larvae).
3. Intermediates:
Intermediates (such as Steinernema feltiae) exhibit a combination of both ambush and cruise foraging behaviors.
Because Steinernema glaseri is highly active and travels deep into the soil to locate subterranean insects, it is classified as a classic cruiser.

Step 3: Final Answer:
Steinernema glaseri is an insect-parasitic nematode that uses a cruiser foraging strategy.
Thus, the correct choice is (2).