Larvae light behavior

[nakoagoss]

Hello,

Has anyone else noticed the larvae's behavior to light? They seem to be attracted to light and move to wherever the light source is. Does anyone know why they move to the light source?

Thanks!

[Varanus]

It is odd since they don't feed as larvae, and the adults seem almost blind compared to the larvae. Perhaps in the wild orienting themselves to the water's surface decreases the chance of them getting tangled in aquatic plants? But that's just a random idea.

[DrKirk]

Opae ula larvae (zoeae) are naturally attracted to light. It's a common behavior among pelagic larval crustaceans. Probably a useful mechanism for dispersal.

[Stalker]

Maybe an atavic behavior from their marine ancestors, they are tough enough and lack of predators to be bothered by this (maybe) useless behavior.

[KenCotigirl]

Interesting that larvae have not been found in their natural habitat.

KenP

[Ace]

Varanus: That is a great idea.
Are we absolutely certain that the larvae do not eat?

Kencotigirl: Really? No larvae have been observe in nature???

[KenCotigirl]

Yes Ace. Larvae and gravid females are not normally observed in archialine pools. This came from the recent book Hawaiian Anchialine Pools by Yamamoto, Iwai jr, and Tagawa, 2015. If memories serve me this was also observed by other researchers or not observed. (Banner, Bailey-Brock) if you are patient I will provide further references. One concern I would have with this lack of observation is it based upon true observations or just repeating what was previously stated.

KenP

[KenCotigirl]

Holthuis in 1973 wrote 'no ovigerous females reported in literature and they have not been observed in nature either. Dr. Maciolek, however in specimens kept in captivity observed the presence of greenish eggs...'

Bailey-Brock in 1993 'berried shrimp have not been found in pools'

Courier and Wong 1978 discussed free swimming larvae but I don't have the article. This was referenced in a 2006 article from Santos.

KenP

[Ace]

KenCotigirl,

Wow! Thank you so much for these more than excellent responses. I need that new book. And I do think it is a good idea to wonder if these are separate observations of just repeated the previously stated.

[DrKirk]

"The reproductive trends and larval biology of anchialine species such as H.[alocardinia] rubra have not been extensively studied. Notably, over 50 years of field surveys have failed to report gravid, egg-bearing females or larvae of H. rubra in the epigeal (i.e., surface) waters of Hawaii’s anchialine habitats (Holthuis, 1963; Maciolek, 1983; Bailey-Brock and Brock, 1993). This implies that the species undergoes reproduction and development in the hypogeal, i.e., underground, portion of the ecosystem (Maciolek, 1983; Craft et al., 2008)."

From: Havird, J.C., Vaught, R.C., Weese D.A., & Santos, S.R. 2015. Reproduction and development in Halocaridina rubra Holthuis, 1963 (Crustacea: Atyidae) clarifies larval ecology in the Hawaiian anchialine ecosystem. Biological Bulletin 229: 134–142.

[KenCotigirl]

DrKirk. I haven't read that article. Thanks for the reference.

KenP

[DrKirk]

Hi KenP,

The paper is a nice analysis. Let me know if you can't acces it, and I can send you the PDF.

Kirk

[KenCotigirl]

Thanks Kirk. I got it.

KenP

[Mustafa]

Alright...someone send me the paper. I requested it but i'm a bit impatient.

[Mustafa]

Alright...someone send me the paper. I requested it but i'm a bit impatient.

Nevermind...got the paper. Incredibly fast reply to my request.