Question

In a laboratory container with 40 fruit flies, if 4 die within a week, what is the mortality rate?

Options

• 0.1 individuals per fruit fly per week

• 0.4 individuals per fruit fly per week

• 0.01 individuals per fruit fly per week

• 0.2 individuals per fruit fly per week

Answer 1

Using the mortality formula:

\[
\begin{aligned}
d &= \frac{\text{Number of deaths per unit time}}{\text{Average population}} \\[4pt]
d &= \frac{4}{40} = 0.1
\end{aligned}
\]

0.1 individuals per fruit fly per week. This represents the death rate per individual per unit time.