VAN TRUMP, W. J.*; PATEK, S. N.; KOEHL, M. A. R.; Univ. of California, Berkeley; Univ. of California, Berkeley; Univ. of California, Berkeley: The California spiny lobster�s runny nose.

Benthic crustaceans use odors in the water around them to find food and communicate with conspecifics. Members of many species flick their olfactory antennules, which bear arrays of chemosensory hairs (aesthetascs). In a few species, it has been shown that water only penetrates the hair array during the rapid downstroke of a flick, hence these antennules sniff (take discrete odor samples in space and time). There is great diversity in the morphology and kinematics of crustacean antennules, and it is not yet known whether other species sniff. We used high-speed video to analyze the kinematics of antennule flicking and SEM to study the morphology of the aesthtasc arrays on the antennules of the lobster Panulirus interruptus to compare the sniffing ability of this species with other lobsters. The morphology is very similar to that of P. argus, a previously studied species, but the flicking behavior is different. P. interruptus flick at higher frequencies, but bouts of flicks are shorter in duration than in P. argus. For P. interruptus, antennule velocity during the downstroke is 80μm/s (similar to P. argus), and during the return stroke is 60μm/s (nearly three times faster than P. argus). Therefore, water should penetrate into the aesthetasc array of P. interruptus antennules during the downstroke, as it does for P. argus, but more water should leak into the hair array during the return stroke for P. interrutus. The aesthetasc arrays of both species operate in a range of speeds in which changes in speed can have a big effect on water flow between neighboring aesthetascs, and hence on odor access. Flicking appears to be sniffing for both species, but whether or not each flick is a discrete sniff for P. interruptus remains to be determined.