Meeting Abstract
1.7 Sunday, Jan. 4 Hiding in the bushes: Structural and chemical determinants of habitat choice in Antarctic amphipods ZAMZOW, J.P.*; AMSLER, C.D.; MCCLINTOCK, J.B.; BAKER, B.J.; Univ. of Alabama Birmingham; Univ. of Alabama Birmingham; Univ. of Alabama Birmingham; Univ. of South Florida jzamzow@gmail.com
Amphipods are important components of near-shore marine environments of the Antarctic Peninsula. Population densities are much higher on highly structured, chemically defended algae (e.g., Desmarestia menziesii) than on simply structured, non-chemically-defended algae (e.g., Palmaria decipiens). Habitat preferences of two Antarctic amphipod species were determined in pair-wise experiments. Fresh thalli and artificial analogues of D. menziesii and P. decipiens were used to elucidate the relative contributions of structure and chemistry to amphipod host-alga choice. Trials were performed in both fresh seawater and water containing chemical cues of the abundant nearshore fish predator Notothenia coriiceps. In fresh seawater, the amphipod Prostebbingia gracilis preferred D. menziesii to all other alternatives. If D. menziesii was not available, P. gracilis preferred fresh P. decipiens over its plastic analogue, and preferred the highly structured analogue to the simple one. In contrast, the amphipod Gondogeneia antarctica preferred P. decipiens over all other alternatives. If P. decipiens was not available, the only preference displayed was for fresh D. menziesii over its plastic analogue. In seawater containing predator cues, preferences of P. gracilis did not change, but G. antarctica preferred fresh thallus of D. menziesii to P. decipiens. In predation experiments using N. coriiceps, more P. gracilis survived on the highly structured D. menziesii and its analogue than on the simply structured habitats. There was no difference in survivorship on fresh thalli vs. their plastic analogues, indicating that structural complexity is sufficient to provide some refuge from predation for P. gracilis.
