Raptorial Appendages Research Articles

ECOLOGY AND MORPHOLOGY OF FEEDING AND AGONISTIC BEHAVIOR IN MUDFLAT STOMATOPODS (SQUILLIDAE)

Agonistic and feeding behavior and morphological structure were studied in five stomatopod crustaceans with raptorial appendages adapted for spearing prey. Agonistic behavior was less frequent and less vigorous than in species adapted for smashing. Of the spearers, the most aggressive species, Cloridopsis scorpio, possessed a heavier raptorial apparatus and constructed the most complex burrow. Harpiosquilla harpax preyed on fish and had the longest raptorial appendages and largest eyes. The remaining species (three Oratosquilla spp. and C. scorpio) possessed similar raptorial appendages but sorted out by water depth, body size, eye size, and length of antennules. The latter two measurements suggest that differences in the structure and function of sensory systems may be important considerations in the analysis of foraging strategies and resource partitioning.

Molting in stomatopod crustaceans. I. Stages of the molt cycle, setagenesis, and morphology.

The description of stages of the molt cycle in mantis shrimp (emphasizing Gonodactylus but compared in a number of Gonodactylidae, Squillidae, and Lysiosquillidae) includes data on texture, hardness, and color of the exoskeleton; behavior; and the micromorphology of the integument and developing setae. After stage A1, when the exoskeleton feels soft and soapy, and A2, when the abdomen attains parchment consistency, the exoskeleton continues to harden until stage C1, when the telson carinae can no longer be depressed with a fingernail. The propodus (C2) and the merus (C3) of the raptorial appendage are the last elements to become rigid. The meral spot achieves indistinct coloration at B1 and distinct but pale coloration at B2; body color continues to intesify until C4. Changes in behavior are particularly marked before and after the molt. After the molt defensive and avoidance behaviors characterize A1 and A2. Threatening increases from low to intense levels in A2 and B1. Striking and offensive behavior increase from weak to normal intensities from B2 to C4. One or two days before the molt, animals lower activity and dominance and feeding levels, exhibit reclusive behavior, and sometimes seal the cavity entrance. The morphology of setagenesis is particularly valuable for determining the stage of the molt after the exoskeleton hardns. The raatio of setae containing cellular contents sthroughout the lumen to those condensed into strands separates stages A2 throught C3...