Question

There are two palatable prey species, Q and R, for an insectivorous bird species in a forest. However, the bird searches for and consumes only species Q. According to optimal foraging theory, which one or more of the following conditions can explain the bird choosing to forage only for Q?

• A. The handling time for Q>the handling time of R
• B. The handling time for Q<the handling time of R
• C. The relative abundance of Q>the relative abundance of R
• D. The relative abundance of Q<the relative abundance of R

Hint:

Remember: Niche partitioning involves differences in \emph{time}, \emph{space}, or \emph{diet}. Any mechanism that reduces direct competition can be considered niche partitioning.

Answer 1

The Correct Option is B, C

Step 1: Profitability in the optimal diet model.

For prey \(i\), profitability is defined as: \[ P_i = \frac{E_i}{h_i} \] where \(E_i\) is the energy (or value) and \(h_i\) is the handling time.

Higher \(P_i \Rightarrow\) more attractive prey; when encounter rates are not vanishingly low, the predator specializes on the most profitable prey.

Step 2: Compare Q and R using handling time.

If Q has lower handling time (all else equal), it has higher profitability: \[ h_Q < h_R \;\;\Rightarrow\;\; P_Q > P_R. \] Thus option (B) supports exclusive foraging on Q. Option (A) would make Q less profitable, hence inconsistent.

Step 3: Role of encounter/abundance.

Higher encounter (greater relative abundance) of Q increases intake rate further and makes specializing on Q more favorable. Hence option (C) supports exclusive choice of Q, while (D) works against it.

Final Answer: \[ \boxed{(B) \;\; \text{and} \;\; (C)} \]