Question

Nutritive chords are present in

• A. Panoistic ovaries
• B. Polytrophic ovaries
• C. Telotrophic ovaries
• D. Hemitromatic ovaries

Hint:

Associate "Telo-" (meaning far end or tip) with "Telotrophic" ovaries, where the nurse cells stay at the very tip, requiring long "nutritive cords" to reach the developing eggs.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The female reproductive system in insects contains ovaries made up of functional subunits called ovarioles.
Ovarioles are classified based on the presence and arrangement of specialized nutrient-providing cells called nurse cells (or trophocytes).

Step 2: Detailed Explanation:
The two main types of ovarioles are:
1. Panoistic ovarioles:
These ovarioles contain no nurse cells.
The developing oocytes obtain nutrients directly from the surrounding follicular epithelium.
This is common in primitive insects like grasshoppers and cockroaches.
2. Meroistic ovarioles:
These ovarioles contain specialized nurse cells.
Meroistic ovarioles are further divided into two subtypes:
- Polytrophic meroistic ovarioles:
In this arrangement, a group of nurse cells travels along with each individual oocyte down the ovariole.
They are directly connected to the oocyte to provide nutrients and RNA.
- Telotrophic meroistic ovarioles:
In this arrangement, all the nurse cells remain clustered at the far tip (germarium) of the ovariole.
As the oocytes move down the ovariole, they remain connected to the distant nurse cells by long, thin cytoplasmic pathways called nutritive cords (or nutritive chords).
These cords act as conduits to transport proteins, RNA, and other essential nutrients from the germarium to the growing oocytes.
This structure is found in Hemiptera (true bugs) and some Coleoptera (beetles).
Therefore, nutritive cords are a defining feature of telotrophic ovaries.

Step 3: Final Answer:
Nutritive cords connect nurse cells to developing oocytes exclusively in telotrophic meroistic ovarioles.
Thus, the correct option is (C).