Fig 1.
Boreotrophon clathratus and drill holes on Balanus crenatus.
(A) Boreotrophon clathratus on Balanus crenatus attached to a Serripes groenlandicus empty shell. Drill holes on a lateral (B) and opercular (C) shell plates of Balanus crenatus empty tests.
Table 1.
Field abundance of live and dead barnacles Balanus crenatus and whelks Boreotrophon clathratus.
Fig 2.
Average proportion of drilled empty tests by size and substrate in the field.
Error bars denote S.E.
Table 2.
Field preservation of opercular plates (tergum and scutum) in empty barnacle tests with aperture length not less than 5 mm by location of drill holes (if any).
Table 3.
Pearson correlations between the parameters of Balanus crenatus and Boreotrophon clathratus in the field samples.
Table 4.
Field caging experiment: SS of type III sum of squares ANOVA on abundance of the whelks Boreotrophon clathratus by the end of exposure and mortality of adult barnacles Balanus crenatus with and without drill holes.
Fig 3.
Contributions of drilled and intact empty tests in total mortality of barnacles in different treatments.
(A) Total mortality of adult barnacles and the proportion of fatally drilled ones. (B) The proportion of drilled empty barnacle tests of total number of empty tests by the end of the experiment. Barnacles with aperture length not less than 5 mm were taken into account. Error bars denote S.E.
Fig 4.
Differential survival of barnacles in predator enclosure cages.
Survival of adult barnacles by tier and lateral contiguity with conspecific neighbors. Pooled data for 6 whelk enclosure cages.
Fig 5.
Weight of predators vs weight of prey consumed.
The relationship of the weight of Boreotrophon clathratus and approximated weight of fatally drilled Balanus crenatus by cage in the field experiment.
Fig 6.
Macrobenthic assemblages associated with live barnacles and their empty tests after 1 year of exposure.
Non-metric MDS on fourth root transformed abundances of 15 most important species standartized by the number of adult barnacles or their empty tests on a substrate. Bray-Curtis similarity. Labels indicate the grid number.
Table 5.
Field experiment: multivariate comparison of macrobenthic assemblages associated with live barnacles (LB) and their empty tests (ET) after 1 year of exposure.
Table 6.
Field experiment: the percentage contribution (individual C% and cumulative S%) of different species to average measures of dissimilarity (D) between the macrobenthic assemblages associated with live barnacles (LB) and their empty tests (ET) after 1 year of exposure, and their average abundance in LB and ET.