Butterfly Metamorphosis Hormones

What is the primary function of prothoracicotropic hormone (PTTH) in butterfly metamorphosis?

How does juvenile hormone (JH) influence the developmental stages of a butterfly?

During which stage is juvenile hormone (JH) absent, leading to the emergence of an adult butterfly?

What role does ecdysteroid play in the metamorphosis of butterflies?

What is the relationship between the levels of juvenile hormone (JH) and ecdysteroid during the larval stages?

Which gland is responsible for producing juvenile hormone (JH) in butterflies?

Hormonal Control of Butterfly Metamorphosis

Neurosecretory cells located in the brain produce prothoracicotropic hormone (PTTH), which is crucial for the metamorphosis process.
PTTH is stored in the corpora cardiaca until it is needed to stimulate transformation.
The release of PTTH prompts the prothoracic gland to produce ecdysteroid, a key hormone involved in insect development.

Juvenile Hormone (JH) Dynamics

Juvenile hormone (JH) is secreted by the corpora allata and plays a significant role in regulating insect stages.
High JH levels in early larva prevent the development of adult characteristics, allowing the insect to remain in the larval stage.
As the larva matures, lower JH levels combined with higher ecdysteroid levels trigger the transition from larva to pupa.

Stages of Development

Early Larva:
- High JH levels prevent adult characteristics.
- Ecdysteroid levels are low, resulting in the insect remaining in the larval state.
Later Larva:
- JH levels decrease, while ecdysteroid levels increase.
- This shift leads to molting into the pupal stage.
Pupa:
- The presence of ecdysone hormone with absent JH facilitates the final transformation into an adult butterfly.

Key Outcomes

Hormonal balance between JH and ecdysteroids is critical in determining developmental stages.
The coordination of these hormones ensures the proper timing and sequence of metamorphosis in butterflies.

Explore the critical role of hormones in the metamorphosis of butterflies. This quiz delves into the functions of neurosecretory cells, prothoracicotropic hormone (PTTH), and how ecdysteroids and juvenile hormone (JH) regulate this fascinating process. Test your understanding of insect development and hormonal interactions.