Do you have a stomatopod with ectoparasitic snails?

[Gonodactylus]

While stomatopods generally are fairly free of ectoparasites, there is a snail in the Indo-Pacific that frequently infects several species of mantis shrimp. The species most commonly infected are gonodactylids such as G. smithii. Stomatopods from the Caribbean such as N. wennerae are not infected. Typically you will see a large female snail sitting between the last pair of the stomatopod's walking legs and a smaller male sitting between the first pair of walking legs. When she is ready to lay her eggs, the female snail will move back onto the gills and attach large egg sacks to the gill filiments. After several weeks, the larval snails hatch. I've attached a picture of a female G. smithii infected. The snail is attaching her egg cases to the stomatopod's gills.

If you receive a stomatopod that is infected, I would very much like to hear about it. Thanks.

Roy

 

[dapel]

Wow, that is just horrible........

 

[Jonny]

does it kill the mantis?

 

[Gonodactylus]

It does not appear to kill them, at least not quickly. The one in the photograph I collected on Lizard Island and kept in Berkeley for over a year. Eventually the snails died and the G. smithii was fine. It is possible that the snails may in some way interfere with the stomatopod molting, but that is something I want to study. Also, I have never found an infected female with eggs.

Roy

 

[amcarrig]

How bizarre! Is the snail visible in the pic or am I just blind?

 

[Gonodactylus]

The small male, about the size of a BB is not visible. The female, about the size of a chocolate chip, is in the shadow right in front of the telson attaching the egg cases. Sorry I don't have a better picture, but I was trying not to disturb the stomatopod so that I could take the shot.

Interestingly, there seems to be just one species of snail. However, it infects animals of very different sizes. On G. affinis that grows to only about 25 mm, it remains tiny. On this 80 mm G. smithii, the female was almost a centimeter across.

Roy