I have some data on stomatopod feeding from the field, but as you can imagine, it is difficult to come by. We collected shell fragments daily from outside 30 G. chriagra cavities for over a month. They were taking two - four items a day, usually snails, hermits and bivalves. Obviously this is an underestimate because they also feed on soft bodied prey that which leave behind no evidence.
We have also used video to continuously monitor N. bredini and O. havanensis if the field. Again, three or four feeding trips away from the cavity or burrow each day.
In another study, we added cavities for N. bredini to a turtle grass flat. We therefore knew how many stomatopods were present before and after the experiment. We also sampled the gastropod and hermit populations weekly. From these data, we calculated that the stomatpods (all in the 35-50 mm size range) were taking 1-5 prey items a day. The averages were two snails and one hermit a day.
I haven't given you the sizes of the prey, but in generally gonodactylids take snails and hermits about 1/4 to almost the size of their thorax (use the carapace as a diameter estimate). For a 2.5 inch N wennerae, this would mean shells about 1/4 to 3/4 of an inch.
As for how much to feed an animalin the aquarium, I subscribe to the practice of moderation (for the stomatopods, not me). I give my animals one piece of food - frozen shrimp, nutrient enriched krill, etc., every three days. The piece is usually about half the size of the carapace. Food not eaten is removed after four hours. In large aquaria that can handle the load of the occasional rotting snail, I will try to add three or for snails every couple of days if they are disappearing. Our animals grow, but perhaps not quite as fast as in the field. However, mortality is reduced probably due to fewer molt problems and better water quality.
Hope this helps.
Roy
