Which of the following is associated with small, pointed protrusions from swollen twig tissue?

Which of the following is associated with small, pointed protrusions from swollen twig tissue?

• A. Pine sawfly
• B. Horned oak gall
• C. Fall webworm
• D. Ips bark beetle

Answer: (B)

The correct answer relates to the horned oak gall, which is characterized by small, pointed protrusions that arise from swollen twig tissue. This condition is typically caused by the activity of certain gall-forming insects, particularly those from the genus Callirhytis, which lay their eggs on oak twigs. The developing larvae trigger a response in the plant, leading to the formation of galls. These galls can appear as bulbous or spiky growths on the twigs, which are a direct result of the plant's reaction to the presence of the larvae. The other options describe different phenomena. For example, the pine sawfly is known for feeding on pine needles, leading to defoliation but does not produce galls or protrusions on twigs. The fall webworm creates silk tents in trees, typically in the foliage, rather than causing swellings or protrusions. Lastly, the ips bark beetle is associated with the boring of holes in the bark of trees rather than the formation of galls on twigs. Thus, the distinguishing feature of small, pointed protrusions from the swollen tissue explicitly identifies the horned oak gall as the correct association.

The correct answer relates to the horned oak gall, which is characterized by small, pointed protrusions that arise from swollen twig tissue. This condition is typically caused by the activity of certain gall-forming insects, particularly those from the genus Callirhytis, which lay their eggs on oak twigs. The developing larvae trigger a response in the plant, leading to the formation of galls. These galls can appear as bulbous or spiky growths on the twigs, which are a direct result of the plant's reaction to the presence of the larvae.

The other options describe different phenomena. For example, the pine sawfly is known for feeding on pine needles, leading to defoliation but does not produce galls or protrusions on twigs. The fall webworm creates silk tents in trees, typically in the foliage, rather than causing swellings or protrusions. Lastly, the ips bark beetle is associated with the boring of holes in the bark of trees rather than the formation of galls on twigs. Thus, the distinguishing feature of small, pointed protrusions from the swollen tissue explicitly identifies the horned oak gall as the correct association.