When it comes to fascinating animals, axolotls are often at the top of the list. These aquatic creatures play a crucial role in scientific research and are much admired. Today, I'm going to share with you the secrets behind the evolution of the axolotl egg, from fertilisation to hatching, through each intriguing stage of its development.
From fertilisation to morula: the first stages of the axolotl egg
Axolotl eggs begin their development from a single round cell, divided into two contrasting hemispheres. The vegetative hemisphere is light, while the animal hemisphere is dark. Gravity plays a key role in this orientation.
Before fertilisation, a maturation spot appears at the top of the animal pole. This spot symbolises the potential for transformation. Between the two hemispheres, a grey crescent develops, indicating the future dorsal side of the embryo.
Once fertilisation has taken place, the egg enters the "blastula" stage. The embryo undergoes its first division, with a furrow separating it into two distinct cells. This stage marks the official start of cell growth.
From there, things accelerate. In around 20 hours, the egg reaches the "morula" stage, a phase in which the embryo becomes granular due to massive cell division. This proliferation of cells is crucial for the final stages in the formation of body structures.
Key evolutionary stages: neurula and caudal bud
The axolotl's development continues at an impressive rate. At 73 hours, the embryo reaches the "neurula" stage. This is where the formation of the nervous system begins. The neural plate and neural bulges gradually form, allowing the visible evolution of the spinal cord and brain.
Between 89 and 100 hours, the embryo enters the caudal bud stage. At this point, key structures such as the vertebral column and somites begin to appear. The somites are the axolotl's future muscles, responsible for supporting its charismatic movements.
The edges of the neural plate begin to join together, forming the dorsal neural tube. This stage is essential for the differentiation of the neural structures, which become clearer with each hour.
Organ development and distinctive morphology
The 100-hour mark is passed, and several notable transformations take place. The head, eyes, gills and body lengthen. From 116 hours, these structures become even more visible.
At 230 hours, the embryo begins to resemble an adult axolotl, thanks in particular to the development of branching gills. At this stage, the embryo takes on a brownish-yellow pigmentation and is transformed into a larva ready to explore the aquatic world.
Optimal conditions for growth and breeding
The health of the parents is essential when rearing axolotl eggs. As a veteran of the pet shop department, I've learnt the importance of breeding legislation. Egg selection is also crucial to eliminate non-viable and malformed eggs.
To ensure optimal breeding, here are a few recommendations:
- Feed: artemia, bloodworms and suitable pellets.
- Environment: regular water changes to prevent disease.
- Monitoring: carefully monitor the health of maturing axolotls.
| Age of egg | Stage of development | Key structure |
|---|---|---|
| 20 hours | Morula | Massive cell division |
| 73 hours | Neurula | Formation of the nervous system |
| 100 hours | Caudal bud | Spine and somites |
| 230 hours | Larva | Gill branches and pigmentation |
Over time, axolotls continue to grow in size and energy. After 3 to 5 months, they reach a size of around 10 cm and become adults. At this stage, the front legs appear first, followed by the hind legs.
Incubation and the beginning of life
Axolotl eggs are generally incubated for between 10 and 15 days. At birth, the juveniles measure between 5 and 8 mm. It's always an exciting moment to see these tiny creatures come to life. They can live up to 10 to 12 years with proper care.
Axolotls are unique in that they remain in a larval state throughout their lives, a phenomenon known as neoteny. They breathe through external gills and retain a juvenile appearance even into adulthood. This is due to an atrophied thyroid gland.
An amusing anecdote from my career in the pet shop came back to me when I was looking after a young axolotl. I had nicknamed this little creature "Axel the flirt" because he always seemed to approach his companions in a curious way. Believe it or not, Axel ended up becoming the star of the department, with customers coming back especially to see him.
In conclusion, axolotls are incredible creatures that deserve all our attention and care. They are not only natural wonders, but also important pillars of scientific research thanks to their exceptional capacity for regeneration.
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