The mystery of the larvae
The larval stage of stomatopods (from when the eggs hatch to when the adults settle onto the reef) is a “black box”—we don't know where larvae go or how long this stage of life lasts. The aquanauts just observed what they could during the Aquarius mission.
At right you see a female stomatopod carefully guarding her pink fluffy mass of eggs. After one to three weeks, the eggs hatch into larvae. Over the next several weeks, the larvae pass through several stages, first in the burrow, and then in the open ocean, growing and molting between each stage. Finally, the larvae leave the open ocean and settle into their adult habitat (coral reef rubble, or sea grass beds). However, for most species, we don’t know how many stages there are, how long each one lasts, or even what the larvae of different species look like!
Female stomatopod with egg mass
Larval stomatopod
The new technology of the Aquarius habitat allowed us to try and answer some of these questions, by allowing us to spend much more time underwater. We looked at larval behavior using a variety of techniques, and hope to eventually answer a variety of questions:
- How much mixing is there between different populations?
- Which larvae grow up into which adults?
- Do the larvae of different species stay deep or shallow at different larval stages?
To answer this last question, the scientists tried “larvae chasing”! The aquanauts caught larvae at night, and the surface support team released them at mid-water to see where they headed—down to deeper waters, or up to shallower areas. All the larvae released swam upward. We're not sure why that is—more questions to explore!