Meeting Abstract
Odor capture is a first step and an important part of olfaction by which odors (chemical signals) are brought into contact with an animal’s chemosensory organs. For marine crabs, odor capture begins by flicking antennules bearing arrays of chemosensory hairs back and forth. This motion drives water in a periodic flow-no flow pattern within the array called ‘sniffing,’ which relies heavily on a range of flicking speeds, hair sizes and spacings, and the properties of water. Terrestrial hermit crabs flick their antennules in air, which has different physical properties than water, with morphologically different hair arrays and a loss of flow between the hairs during flicking. Here we examine whether the morphological changes between a marine crab (Callinectes sapidus) and terrestrial hermit crabs (Coenobita rugosus) confer a performance advantage in terms of odor capture in their native fluid environments through computational simulations of antennule flicking. We find that the sniffing of marine crabs outperforms the non-sniffing flow patterns of terrestrial hermit crabs in water but not in air, where terrestrial crabs capture several times the available fraction of odor concentration. Furthermore, the size of the odor filament also plays a role, wider filaments enhances odor capture for terrestrial crabs which flick for longer duration. Terrestrial hermit crabs also experience intermittency in continuous odor filament despite not sniffing. Our results suggest that sniffing may only be important where molecular diffusivities are low relative to the organ’s size and speed or contained within an internal structure.
