Meeting Abstract

63.2  Thursday, Jan. 6  Sensory Mechanisms Driving Community Ecological Interactions FERRIER, G.F.*; KIM, S.J.; LOO, J.A.; ZIMMER, C.A.; ZIMMER , R.K.; Univ. of California, Los Angeles; Univ. of California, Los Angeles; Univ. of California, Los Angeles; Univ. of California, Los Angeles; Univ. of California, Los Angeles gferrier@ucla.edu

Sensory systems provide critical filters that enable organisms to detect and recognize valuable resources. Specific molecules serve as chemosensory stimuli and play keystone roles in determining outcomes of species interactions at multiple trophic levels. Here, we investigated the contributions of surface-associated proteins as signal molecules within wave-swept, rocky intertidal habitats. Using ion-mobility analysis (ESI-GEMMA), barnacles (Balanus glandula) were found to produce a high molecular weight (~390 kDa), insoluble, glycoprotein complex (MULTIFUNCin) for cuticle/shell formation. A primary subunit (~199 kDa) of this evoked settlement of conspecific larvae, thereby operating as a seminal recruitment cue. The same subunit triggered predation by numerically dominant whelk (Acanthinucella spirata, Nucella emarginata, N. ostrina, N. canaliculata, and N. lamellosa) and seastar (Pisaster ochraceous) species on barnacles in lab and field assays. Complete nucleotide translation from a sequenced 5.1 kb mRNA transcript identified the glycoprotein as consisting of 1,550 amino acids (mw = 171 kDa). This protein simultaneously influences demographic processes that enhanced, or diminished, barnacle populations. Structural elucidations further revealed significant homology (72%) among amino acid sequences of settlement cues between barnacle species (B. glandula and B. amphitrite), inhabiting different biogeographical provinces (Pacific and Atlantic coasts of North America, respectively). As dominant competitors for space, the balance between barnacle recruitment and predation mortality has strong, cascading direct and indirect effects on community dynamics. Contact protein cues thus act as critical factors structuring species assemblages within natural habitats.