Question

Arrange the bark beetles according to increasing mortality percent of trees.
A. Scolytus scolytus
B. Ips typographus
C. Dendroctonus ponderosae
D. Phloeosinus neotropicus
E. Dendroctonus frontalis
Choose the correct answer from the options given below :

• A. A $<$ B $<$ C $<$ D $<$ E
• B. B $<$ A $<$ C $<$ D $<$ E
• C. E $<$ D $<$ B $<$ A $<$ C
• D. E $<$ B $<$ D $<$ A $<$ C

Hint:

Bark Beetle Lethality Drivers: Aggressive mass-attacking species (Dendroctonus spp.) kill living host trees rapidly by disrupting phloem transport and introducing phytopathogenic blue-stain fungi.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question requires arranging the specified bark beetle species (Curculionidae: Scolytie) in ascending order of their tree mortality impact percentage.

Step 2: Key Concepts & Relative Lethality of Bark Beetles:

• A. Scolytus scolytus (Large Elm Bark Beetle): Primary vector of Dutch Elm Disease. Causes moderate mortality primarily via fungal transmission.
• B. Ips typographus (European Spruce Bark Beetle): Causes significant mortality in stressed Norway spruce forests during outbreak cycles.
• C. Dendroctonus ponderosae (Mountain Pine Beetle): Extremely destructive species capable of killing healthy pine stands across vast North American regions.
• D. Phloeosinus neotropicus: High mortality vector in specific regiol host species.
• E. Dendroctonus frontalis (Southern Pine Beetle): One of the most aggressive insect species globally, inducing exceptiolly high tree mortality rates through rapid mass-attack mechanisms.

Step 3: Detailed Explation:

• Mass-attacking bark beetles carry blue-stain fungi and girdle phloem tissues.
• Ordering the species from lower relative tree mortality percentage to higher mortality rate yields the sequence: \[ A \, (\textit{Scolytus}) < B \, (\textit{Ips}) < C \, (\textit{D. ponderosae}) < D \, (\textit{Phloeosinus}) < E \, (\textit{D. frontalis}) \]
• This corresponds directly to option (A): A $<$ B $<$ C $<$ D $<$ E.

Step 4: Fil Answer:
The correct order is A $<$ B $<$ C $<$ D $<$ E. Thus, option (A) is correct.