THE VELIGER © CMS, Inc., 1988 The Veliger 31(3/4):1922O3 (October 3, 1988)
Feeding Biology of Oceriebra lurida (Prosobranchia: Muricacea): Diet, Predator-Prey Size Relations, and Attack Behavior
by
A. RICHARD PALMER
Department of Zoology, University of Alberta, Edmonton, Alberta T6G 2E9 and Bamfield Marine Station, Bamfield, British Columbia VOR I B0, Canada
Abstract. Field observations on individuals from an unusually dense intertidal population of Ocenebra lurida (Middendorif, 1849) revealed several interesting features about the feeding biology of this rather enigmatic predatory neogastropod. (1) Unlike the more common drilling gastropods in the northeastern Pacific, 0. lurida preyed most heavily upon limpets: of 231 feeding observations, 55.0% were limpets (Lottta pelta [Collise//a pc/ta], L. strigatella [C. strigatella], and Tectura scutum [Notoacmea scutum]), 42.0% were barnacles (Ba/anus glandula, B. crenalus, Semibalanus cariosus, and Chthamalus dalli), 2.2% were mussels (Mytzlus edo/is), and 0.8% were other prey (Ca/liostoma ligatum and Spirorbis sp.). (2) The mean size of both limpets and barnacles consumed increased with increasing predator size, although this increase was not significant statistically for barnacles. (3) Over a broad range of predator size, both the mean and the maximum shell length of eaten T. scutum exceeded that of L. pelta (by 7 and 5 mm respectively). This observed difference in maximum shell length corresponded rather closely to that expected if the limit to vulnerability were determined by shell thickness, but it could also have resulted from differences in food value between the two species. (4) As observed for the Australian Dzcathazs aegrota, the distribution of drill sites on limpet shells was distinctly nonrandom: 85% of 124 drill holes were located in the posterior half of the limpet’s shell and 95% were medial to the pedal retractor muscle scar. (5) When eating limpets, 0. lurida tended to consume the gonad first, followed by the digestive gland and then the foot, but the foot was eaten only when the shell length of the limpets was less than that of 0. torte/a. (6) When feeding on the barnacle Semibalanus carlosus, 0. lurida attacked lateral wall plates almost exclusively (37 of 38) and nearly half of the attacks (46%) occurred at the sutures between adjacent plates. Because sutures form only about 15% of the periphery, these results suggest a preference for sutural attack. (7) Patterns in the degree of completion of unfinished drill holes suggest that larger 0. torte/a attack limpets sooner after tidal immersion than smaller ones.
INTRODUCTION MAN & BANNER, 1949; CHEw & EIsLER, 1958; HANcOCK, 1960). Two species of Ocenebra have also been studied Depending on the taxonomic authority, from four to six under more natural conditions: 0. pun/sum from California species of the cosmopolitan neogastropod genus Ocenebra (FOTHERINGHAM,1971) and 0. lumaria from Japan occur along the shores of the northeastern Pacific (KOzLOFF, (LucKeNs, 1970a, b). Information on the biology of species 1987): 0. interfossa Carpenter, 1864, 0. torte/a (Midden from the northeastern Pacific, however, is scarce and con dorff, 1849), 0. orpheus (Gould, 1829), 0. painei (Dali, sists either of anecdotal observations (geographic range, 1903), 0. sc/era (Dali, 1919), and the introduced 0. ja shell color variation, and an unusual mode of feeding in ponica (Dunker, 1869) . According to RADwIN & D’A’rTI 0. turida; TALMADGE, 1975) or circumscribed data col Lb (1976), however, 0. sc/era is a synonym of 0. lurida lected as part of a larger study (feeding and growth in the and 0.japonica is actually Ceratostorna inornaturn (Rbcluz, laboratory, and notes on natural densities of 0. interfossa 1851), Because some species are pests, much of the knowl and 0. lurida; SPIGHT et at., 1974). In addition, although edge of the feeding biology of Ocenebra derives from studies prey items have been reported for various Ocenebra species of species in commercial oyster beds (BARRY,1981; CHAP- worldwide, most of these reports consist of laboratory or
A. R. Palmer, 1988 Page 193
anecdotal observations; hence, remarkably little is known 1.2 0 about the normal feeding biology of species in this cos . L. pelta 0• mopolitan genus. 0 1’.scutum 1.0 . —: MATERIALS AND METHODS Most of the field observations were obtained from an un 0.8 0 usually dense intertidal population of Ocenebra lurida (ap . prox. 1—3/rn on the east side of Turn Island, San Juan 0.6 Islands,2 Washington 48°32’ I ) (US.A.; 10”N, 22°58’ I 0”W). These observations were made during low tides on five different dates from 1 April to 12 May 1978 (1 IV, 2 IV, 7 V. 10 V, 12 V). A few additional feeding observations were also recorded from Tatoosh Island. Washington 5 10 15 20 25 (48°l9’N, l2440’W) on 29—30July 1978. The habitat at Ocenebra Shell Length (mm) Turn Island consisted a of heterogeneous assemblage of Figure 1 rocks and boulders interspersed with bedrock promonto Average outer diameter of drill hole ([max. + ries. Most feeding observations were obtained from the diam. mm. diam.],i 2) as a function of Ocenebra lurida shell length for two species of lower shore (—0.5 to +0.5 m, U.S. datum). Within this limpets, Lottia pelta and Tectura scutum. tidal range the rock surfaces were rather barren. Macro- algae were virtually absent, and barnacles were sparse and nearly all roughly one year old or less based on size (<10 Statistical analyses were conducted using the microcom mm basal diameter) and lack of weathering on the skeletal puter routines in Statview 512+€ (Version 1.0. Abacas plates. Limpets were the most conspicuous invertebrates. Concepts, Berkeley, CA, U.S.A.) except for the analysis The shell lengths (apex to tip of siphonal canal to 0.1 of covariance (ANCOVA) and multi-way contingency ta mm) of both feeding and nonfeeding snails were recorded ble analyses which were conducted with BMDP Statistical as well as the number of mating pairs observed on most Software (programs IV and 4F respectively; DixoN, 1983). dates. If a snail was feeding, the size and identity of its prey were also noted. Prey size was measured with Vernier RESULTS calipers to 0.1 mm as follows: limpets—shell length and Activity shell width; barnacles—anteroposterior opercular diame and Diet ter inside the parietal plates; mussels—maximum shell At Turn Island, from 59 to 103 Ocenebra lurtda were length. observed per day when the feeding observations were made. Many but not all prey items observed being attacked ‘Vith one exception, on each date the majority of snails were collected and taken to the laboratory to determine found were in the process of feeding (mean percent feeding more precisely the location of attack, the extent of tissue = 61% ± 12,4 SD, n = 5 dates, range = 44—75%), and eaten, and, for limpets, the degree of completion and size no significant difference in shell length existed either among of the drill hole. The percentage completion of unfinished dates (P = 0.54), or between those feeding and those not drill attacks was estimated by eye as a percentage of the feeding on a particular date (P = 0.34 between activities; shell which had been penetrated at the site of attack. Both two-way ANOVA). maximum and minimum outer drill hole diameters in the A total of 241 prey items from 11 species of prey were limpet shells were measured under a dissecting microscope observed in the diet (Table 1). At Turn Island, Ocenebra using a calibrated ocular micrometer. For both of the com litrida preyed predominantly upon limpets (55.0%), almost monly consumed species of limpets, average diameter (mean exclusively Tectura scuturn (Rathke, 1833) (Votoacrnea of maximum and minimum diameters) of completed drill scufum) and Lottiapelta (Rathke, 1833) (GoI!isella pc/ta) holes correlated highly with Ocenebra lurida shell length (following the nomenclature of LINDBERG [1986]). Bar (Figure 1; r = 0.88; n = 52). Using this regression, pred nacles of four species formed the second most common ator size was estimated for a sample of drilled, dead shells component of the diet (42.0%; primarily Sentibalanus cart collected at the time of the feeding observations. The only osu.s (Pallas, 1788) and Ba/antis glandula Darwin, 1854, other predatory gastropods observed in the immediate vi but also B, crenatus Brugière, 1789, and Chthamalz,s dalit cinity were the buccinid Sear/esia dire and the thaidid Thais Pilsbry, 1916). Mussels (Mtt/us edults L.), C’ailtostorna emarginata (.Vucella ematglnata). Because buccinids are ligaturn (Gould, 1849), and .S’ptrorbtssp. were eaten only not known to drill (TAYLOR eta!.. 1980), and T emargiri ate occasionally Although no quantitative observations were eats limpets only extremely rarely (see discussion), 0. It, made of actual prey availability at this site, the proportions rIde was most likely responsible for the drill holes in these of prey eaten appeared to be representative of the pro dead limpet shells. Furthermore, because of their circular portions available on the lower shore. Barnacles made tip to subcircular outline and nearly parallel sides in the upper a large fraction of the observations from Tatoosh Island half, these holes would not have been made by octopus. (80%; Table I); because of the very small sample size, Page 194 The Veliger, Vol. 31, No. 3/4
Table I Species composition of the diet of Ocenebra /urida and mean size of predator consuming each prey species from two sites. Observations for Turn Island were pooled over five days.
Turn Island Tatoosh Island Mean predator shell Mean predator shell Prey species n (%) length (mm; ± SE) n (%) length (mns; ± SE) Limpets Tuctura scutum 48 (20.8) 19.4 ± 0.53 — Lttia pc/ta 78 (33.8) 19.4 ± 0.38 2 (20) 19.3 ± 2.30 L. strigatella 1 (0.4) 21.1 — Total limpets 127 (55.0) 2 (20) Barnacles Scm/ba/anus cariosus 71 (30.7) 19.3 ± 0.32 3 (30) 18.2 ± 1.86 Ba/anus glandula 17 (7.4) 19.1 ± 0.69 3 (30) 18.6 ± 1.89 B. nubilus — — 1 (10) 15.4 B. crenatus 3 (1.3) 19.5 ± 2.30 — Chihamalus dat/i 6 (2.6) 17.9 ± 1.86 1 (10) 9.1 Total barnacles 97 (42.0) 8 (80) Other species .liytilus edulis 5 (2,2) 19.4 ± 0.42 — Ca/liostorna ligatum 1 (0.4) 18.9 —
Spirorhis sp. 1 (0.4) 2.8 Total other 7 (3.0) Total observations 231 10
however, this value may not be representative for the pop 0.93; one-way ANOVA on predator shell length for all ulation as a whole. prey species for which more than five observations were recorded). One possible suggestion of a size-related dietary Predator-Prey Size Relations difference was the single observation of a 1.5-mm-diameter Sptrorbts sp. being consumed by a 2.8-mm 0. lurida; Spiror For the two most commonly consumed species of limpets, his may serve as an alternative prey for very young snails. Tectura scu turn and Lottia be1ta, both the mean size (log- transformed to homogenize the variance) and the size range Patterns of Drilling and Tissue Consumption of prey eaten increased with increasing predator size (Fig in Limpets ures 2a, b). A similar trend was observed for the two most commonly consumed barnacle species, Scm ibalanus cariosus When Ocenebra lurida attacked limpets, drill holes were and Ba/onus glandula, but in both cases the increase in clustered in the posterior half of the shell (82.8% and mean, log-transformed prey size was not significant (P = 86.4%), and nearly all (98.3% and 92.4% for Tectura scu 0.096 and P = 0.24 respectively; Figure 2c). Somewhat turn and Lottia pelta respectively) were within the perim surprisingly, a given sized Ocenebra lurzda ate significantly eter of the pedal retractor muscle (Figure 3). All of these larger T. scuturn than L. pc/ta on average (P < 0.001, frequencies differ significantly from those expected if 0. .\NCOVA on log-transformed predator and prey shell lurida drilled these regions in proportion to the area of the lengths—a small, but statistically significant difference ex shell they represent (50% anterior vs. posterior, and 58.5% isted between the slopes [P = 0.033], but this would di and 56.3% for the area internal to the muscle scar in T. minish rather than amplify the difference between adjusted scuturn and L. peita respectively; P < 0.001; with Yates’ means). For a mid-sized 0. /urtda (19.0 mm), the adjusted correction for continuity, x2 values all exceeded 23 for 1 mean prey sizes were 18.6 mm (95% confidence interval df). A multiple-regression analysis revealed that larger 0. = 16.O—21.5)and 9.7mm (95% confidence interval 8.7— lunda tended to drill closer to the apex than smaller ones, 10.9) respectively. In addition, over a broad range of pred hut this relationship was not strong (Figure 4) and was ator size, the maximum size of T scuturn eaten exceeded significant statistically only for T. scuturn (Table 2). A that of I.. pc/ta (Figures 2a. h). similar analysis of drill-site location along the anteropos Although the mean and range of sizes of prey eaten tenor axis of limpets revealed no significant associations increased with increasing predator size, the average size with predator or prey size. Hence, the site of attack did of Occni’hra fonda eating a particular species of prey did not depend strongly upon either predator or prey size. not vary among prey species (Table 1; F = 0.272, P = Ocenebra lurida also appeared to consume limpet tissue A. R. Palmer, 1988 Page 195
in 50 a repeatable order (Table 3). Following completion of • Live limpet a) the drill hole, the gonad to appeared be eaten first, followed E o Dead shell by the digestive gland. and both were completed before the !40 foot was attacked. In only a small portion of the cases (8 0 of 58) was the foot actually being consumed. These were 30 restricted to cases where the limpets were small relative to the size of the predator (Figure 5). although this pattern was not quite significant statistically (P = 0.056; contin gency table analysis of counts of the ratio prey length predator length that were pooled into four cate gories [<05, 0.5—0.99. 1.0—1.49, 1.5] to reduce the im pact of small frequencies per cell). b) : :d1nt Biases Associated with Feeding Observations During Low Tide From 7 T.scutum,,,,,,,,zz To assess whether feeding observations obtained at low tide were biased by differences in handling times (FAIR- :: b. • •• WEATHER& UNDERwooD, 1983), at least with respect to the sizes of limpets being eaten by different sized Ocenebra 10 lzirida, attacks on limpets were divided into two groups :• based on whether drilling was still in progress or whether drilling was completed and flesh was C) being consumed. The E 5.0 S. cariosus • proportion of completed holes B. glandula drill declined with increas • 9.8 ing limpet size for both species of limpets (Table 4a) but B. crenatus this decline was not significant statistically for either species 4.0 0 C. dalli or when both limpet species were analyzed simultaneously via a multi-way contingency table (Partial P = 0.076, 3.0 Marginal P = 0.07 5 for dependence of hole status on limpet size; full analysis not presented—P> 0.5 for all remaining D 20 0 second and third order effects). In addition, although a 0 higher overall proportion of drill holes had been completed w...... 9 on Lottia pelta than Tectura scutum (Table 4), this differ 5 10 15 20 25 ence was also not significant 2(x = 0.36, P > 0.5; 2 x 2 Ocenebra Shell Length (mm) contingency table analysis). Curiously, when considering Figure 2 only those cases where drilling was still in progress, the Prey size as a function Ocenebra lurida degree of completion of the drill hole actually increased of shell length for six species of prey. (a) Tectura scutum (the line, fitted by eye, rep with increasing limpet size, although this relationship was resents the upper limit to the size of limpet eaten where the significant statistically only for L. pelta (P = 0.022; Figure predator size was known with certainty), (b) Lottiapelta (the line 6a). is identical to that in [a] for comparison), and (c) four species of The proportion of Ocenebra lurida that had completed barnacles. The regression equations of prey size (Y) on predator drilling and were eating flesh did not vary dramatically size (X) for the four most common prey species are (slope ± SE): T. with predator size either (Table 4b). The largest 0. lurida scutum, log(Y) = 0.415 + 0.045 ± 0.0080 log(X) 2(r = 0.34, P < 0.001, n = 66); L. pelta, log(Y) = 0.554 + 0.023 ± were least likely to have completed drilling on both species 0.0064 log(X) 2(r = 0.14, P < 0.001. n = 82); S. carlosus, Iog(Y) of limpet; however, the overall trend with predator size = 0.059 ± 0.011 ± 0.0063 log(X) 2(r = 0.04, P = 0.096, n = was not consistent between species and the differences with 74); B. g!andula, log(Y) —0.147 + 0.018 ± 0.0149 log(X) predator size were only weakly significant for Lottta pelta. 2(r = 0.077. P = 0.24. n = 20). For the cases where drilling was still in progress, however, the degree of completion of the drill hole declined signif proportion of drill hole completed on both limpet and icantly with increasing predator size for L. pe/ta (P = 0.007; predator size for the smaller sized limpet (Lottza pelta). Figure 6b) but no such relationship was observed for Tec tura scutum (P 0.9; Figure 6b). Patterns of Drilling and Tissue Consumption As a whole, when considering the larger of the two in Barnacles limpet species (Tectura scuturn), the status of the drill hole in these observations made at low tide was unbiased with When attacking the barnacle Semtbalanus cartosus, Ocr respect to either limpet or predator size. The only consis nebra lurida drilled lateral plates almost exclusively and tent bias these data revealed was a dependence of the nearly half of these attacks occurred at the margins between Page 196 The Veliger, Vol. 31, No. 3/4
Shell Margin Lottia pelta Tectura scutum Figure 3 Polar coordinate plots of sites of attack by Ocenebra lunda on two species of limpets, Lottiapc/ta and Tee/nra scutum; distance from origin = (distance from apex to center of drill hole)/ (distance from apex to shell margin in the same direction as the drill hole). Note that the origin of these figures corresponds to the apex of the shell even though the apices of these limpets are not precisely in the center of the shell.
plates (Table 5). Too few attack sites were noted for the opercular plates even though the site of drilling was located remaining species to discern any patterns although, in elsewhere. Similarly, in the 12 cases in which it was pos contrast to S. carzosus, 3 of 5 attacks on Ba/anus glandula sible to verify that S. carzosus tissue had been consumed, occurred at the opercular plates. For all barnacle species the drill hole was found to be too small to permit passage pooled, the frequency of attacks at the sutures between of the proboscis: the diameter of final penetration was well skeletal plates nearly equalled that through the plates. less than half the outer diameter. Curiously, in the eight instances where the proboscis Maturity and Reproduction was observed unambiguously (six cases for Serniba/anus On three dates, notes on the degree of closure of the canosus, and one each for Ba/anus glandula and Chtham siphonal canal and the sizes of copulating pairs were re a/us) it was always observed to be inserted between the
50 Margin No Foot Ate Foot 40 • 0.8 0 0 0 30 00• • 0 5? 0.6 . 0 a 0 •0 I-5? 0.4 0 .. ‘I. 10 0.2 L. pelta 0 • :ooo0 . 0 0 T. scutum .25 .5 .75 1 1.25 1.5 1.75 2 2.25 Apex Prey Length/Predator Length 5 10 15 20 25 Figure 5 Ocenebra Shell Length (mm> Frequency with which Oceriebraiurzda was observed to be con Figure 4 suming the foot of limpets as a function of the ratio of the shell Location of drill site (expressed as proportion of distance from lengths of prey and predator. Data for Tectura scutum and Lot/ia apex to margin of shell) as a function of Ocenebra lurtda shell pc/la combined. No foot—other tissues had been consumed, but length for two species of limpets, Lott,a pc/ta and Jectura sen/urn the foot was still intact. Ate foot—at least some portion of the see Table 2 for statistical analysis). foot had been consumed. A. R. Palmer, 1988 Page 197
Table 2 Results from a multiple-regression analysis of drill hole position (dependent variable = proportion of distance from apex to shell margin) as a function of Ocenebra fonda and prey size (data in Figure 4).
Lottia pelta Tectura scutum Coefficient Intercept 0.637 0.683 Ocenebra shell length (mm; a SE) —0.0081 ± 0.00547 —0.0150 ± 0.00604 Significance of coefficient (P) 0.15 0.016* Limpet shell length (mm; ± SE) —0.0042 ± 0.00355 0,0007 ± 0.00206 Significance of coefficient (P) 0.24 0.74 r2 0.080 0.112 P (from ANOVA) 0.069 0.038*
P < 0.05.
corded for Ocenebra fonda (Figure 7). Three categories of DISCUSSION canal closure were recognized: fully open, transitional (be Limpet-Feeding Habit ginning to close), and completely closed. Several lines of evidence suggest that the degree of closure of the siphonal Ocenebra fonda appears to be an unusual member of canal reflects the state of maturity: (a) all individuals above the drilling gastropod fauna of the northeastern Pacific 22 mm shell length had fully closed siphonal canals, (b) all individuals less than 16 mm had fully open siphonal • L. pelta 0 T. scutum canals, (c) snails noted actively copulating all had fully J 1.0 a) closed siphonal canals, and (d) the size distribution of 0 0 copulating snails was indistinguishable statistically from • • 0 0.8 0 00 that of solitary snails with closed canals 2(x = 2.06, P = • 0 0.56, for the four size categories: <18.9, 19.0-.20.9, 21.0— 0.6 • . 22.9, 23). The siphonal canal thus does not appear to o• • 0 close intermittently over the life of an individual snail, a • • E 0.4 •• 0 0 pattern which parallels rather closely that reported for 0. • 0 C) • 0 lomaria (LuCKENs, 1970b). Using this criterion, maturity 0.2 .. • 0 occurred around 16 to 19 mm shell length (Figure 7). • 0.... 0 Although no egg capsules were noted, from 3 to 5 cop rt 10 20 30 40 ulating pairs were observed (mean = 11% ± 3.2 SD, = 1 4, range = 7.1—14.3% of all snails observed on each date) Limpet Shell Length (mm) on all but the last date of observation at Turn Island (12 May). In addition, one copulating pair was observed out • b) 0 0 of 12 snails on Tatoosh Island on 5 July. Hence, although 0 • is delimited by these 0 the reproductive season by no means 0 data, they do indicate that active copulation was occurring . in spring and early summer and are consistent with late o• 0 • the times of reproductive activity noted by SPIGWr et al. • ... (1974). .00 • 0 0 ._ 0 • Table 3 • • • • .o.. 0 Frequencies with which Ocenebra fonda were observed to 10 15 20 25 have consumed various portions of limpet flesh. Data from 0. lurida Shell Length (mm) all limpet species pooled, but only for cases where the drill hole had been completed. Figure 6 Proportion of drill hole completed through the shell as a function Tissues eaten n (%) of limpet size (a) and size of Ocenebra fonda (b) for two species None 8 (13.8) of limpets. Multiple regression equations for each limpet species Gonadonlv 30(51.7) are (coefficient ± SE): I.ott,a peita (Ti = 27)—proportion com Gonad + digestive gland only 12 (12.7) pleted = 0.018 ± 0.00?(prey length. P = 0.022) — 0.042 a 0.01 + Gonad -4- digestive gland + <50% of foot 3 (5.2) 4(predator length. P = 0.007) 0.959; Tectura scuturn(n = Gonad ± digestive gland ± >30% of foot 5 (8.6) 19)—proportion completed = 0.010 ± 0.00(prey length, P = 0.17) ± 0.004 ± 0.035(predator length. 7P = 0.91) + 0.171. Page 198 The Veliger, Vol. 31, No. 3/4
Table 4 30 Siphonal Canal: Open Frequencies at which Ocenebra lurida were found in the fl process of drilling vs. feeding on live limpets as a function Transitional of prey and predator size. Class limits are shell lengths 20 Closed (Solitary) (mm) and were chosen to obtain frequencies as nearly • Closed (Copulating) equal as possible. P values from two-way contingency table analyses. 10 a) Sizes of limpets in the process of being drilled or eaten Lottia pelta Tectt4rascutum Prey Prey 10 12 14 16 18 20 22 24 26 Prey class Drilled Eaten class Drilled Eaten Ocenebra Shell Length (mm) percentile limit n n (%) limit n n (%) Figure 7 Smallest Y3 <7.8 5 16 (76.2) <21.5 5 8 (61.5) Middle ½ 9 12 (57.1) 6 7 (53.8) Frequency of Ocenebra lurida observed at different degrees of Largest ½ 11.3 13 10 (43.5) 31.0 8 6 (42.9) closure of the siphonal canal in the latter part of the study. active P = 0.088 P = 0.62 Open—siphonal canal fully open, shell still exhibiting recent growth; Transitional—siphonal canal beginning to close over, apertural lip beginning to thicken; Closed—fully closed b) Sizes of 0. lunda in the process of drilling or eating siphonal canal, usually with a thickened lip, little or no evidence Lottia pelta Tectura scutum of recent shell growth (solitary—individual snails in the field; copulating—snails observed actively copulating in the field). Preda- Preda tor tor Predator class Drilled Eaten class Drilled Eaten percentile limit n r, (%) limit n ri (%) larger fraction of the diet overall for T. emargrnata from ½ 9 12 (57.1) <19.4 4 9 (69.2) Smallest <18.8 central California (30 of 632 observations). Limpets are Middle ½ 5 17 (77.3) 6 7 (53.8) uncommon in the diets of other thaidid gastropods Largest ½ 21.3 13 9 (40.9) 22.0 9 5 (35.7) also STIMS0N noted that, P = 0.049 P = 0.22 from this geographic region. (1970) when given a choice of Mytilus edults and lottiid limpets in the lab, Acanthina spzrata consumed mussels exclusively, because of the high frequency with which it consumes and LuBCHENc0 MENGE (1974) reported that Acanthina limpets (53.5%; Table 1). Limpets are at best rare in the purzctulata rarely consumed limpets (4 of 132 observations) diets of species of Thou (or Nucella) including T. canalzcu even though limpets were available. Hence, at most, lim lata (1 out of 2001 observations), T. ernarginata (4 of 2082 pets make up less than 5% of the diet of thaidid gastropods observations), T. lamellosa (0 of 889 observations), and T. from the northeastern Pacific. lima (14 of 518 observations; all from PALMER, 1980). Among non-drilling gastropods, Searlesia dira also con STIMs0N (1970) also reported only a single instance of T. sumes limpets regularly (from 10 to 31% of diet; L0uDA, ema,ginata drilling a Collisella scabra and reported no at 1979). However, because Searlesu.z appears to feed pri tacks on Lottia gigantea. WEsT (1986), on the other hand, marily via scavenging (L0UDA, 1979), the prevalence of reported that limpets (mainly C. scabra, but occasionally limpets in the diet more likely reflects their availability as Lottia limatula [Golizselia izmatulaj) made up a somewhat dislodged or moribund prey than a dietary preference.
Table 5 Frequencies of attack by Ocenebra lurzda at various locations on the skeletal plates of barnacles; data from Turn Island and Tatoosh Island pooled.
. Unable to Parietal plates Opercular plates determine Prey species At Suture Through Total At suture Through Total drill site
Sem,baiartus cariosus — 1 1 17 20 37 13 Ba/artucgiandula 3 — 3 1 1 2 5 B. crenatu.c — — — — — — 2 B. nuh,lus — — — I — I — C’hthamaius dali, — — — I — 1 2
Total (%) 3 (75.0) 1 (25,0) 4 (6.0) 20 (48.8) 21 (51.2) 41 (61.2) 22 (32.8)
scutum
because
it
available
attack
lower
at.
through
constraint
1980).
tistically,
by
Thais barnacles
was
consumed
pattern the
size
size
frequency of
MENGE, highly
BRooM, prey
three occasions.
per gastropods
may ternative
sufficiently most
Predator-Prey
nacles
gastropods
shed
curious all
MORAN, WEST,
pet-inhabited and
frequently are
spicuous
recognize gastropods
1984; matic
A.
rapidly
The
As laboratory
Perhaps
small
The
(1981)
of
northeastern
unit
of consumed
observed
range,
R.
are
be
references
no
emarginata
of
thaidid
them
food in
large
observation
for
than and
prey both
McQuAID,
no
in
sufficiently
which was the
for
relative
Palmer,
1982; light
0.
comparable
in
handling
1972; other
prey
enough
1985).
available
presumably
component
species
two
press;
of
measurements
them
Ironically,
imposed
for
mussels
larger value
limpets
lurida increased
upon
simply
predictable
four attack
these
from
items in
mussels
from
Lottia
limpets
most
choice
gastropods
for
on
on reasons:
HUGHES,
shores
Folinices.
frequently
terms they
PAINE,
predator-prey
Size
therein),
as
The
reviewed
most
rarity
such Pacific
which
this
of
before limpets
barnacles
of
on
reasons. the
prey. the
eaten
time
pelta
that
limpets
potential
striking
at
reject
1988
are
common
1985;
which
limpet
experiments
can
by
large
because, in
large to
of
Relations
rarity
for
with
problem.
of
the (BLAcK,
energy
northeastern
northeastern
a
because
1976;
(1)
Ocenebra a
the
that
that,
a
the
electivitv
were they of
drill,
by
it
decline
was
1980;
remains
this Alternatively,
(TAYLoR
were
lower
the are
small
site
limpets
by
and
in
begins
MENGE,
make
Unfortunately
limpets
by
limpets
(Figures
limpets
limpets
diet
increasing
Ocenebra
of
but
maximum
of
for
grow
BNcH,
prey
and VERMEIJ, other
when
starfish
rich
unexpected. common
limpets, rocky
as
studied.
drilling
even
limpets systems
LuBcHENc0
taken the
(2)
of
1978;
snail
of
quality
it
occurs
the
observed
up
(MENGE,
lurida
their
a
in
to
the
prey
thaidid as
(MERcURI0
was
rapidly
predator
could
predators
et
gastropods
are
to
given
puzzle.
though
in
Pacific
2a,
Pacific
decompose
shore
the
the
1973;
two
on
is
lurida,
undesirable
at., Leptasterias
FAIRwEATHER
in
small small
(e.g.,
The
and
predator
on
1981),
the
a
availability
not
unable
in
where
when
ate
b). 1978),
thickness
prey
limpets
it
bulk
field
the common
reflect
1980).
a
most
terms
by many
gastropods the
(PALMER,
Unfortunately,
community
could
A
1972).
limpets
significant
diet
lack
larger MoORE,
more choice,
MENGE, is
(BERRY, MENGE,
is
as
diet
size
0.
than
similar KITcHELL which
and
of
although
small
present
rather
to
the
particularly
the
which
et
well
commonly
a
accessible (PALMER.
of
lurida.
size. of
of the
other
These
of
consume
reflect aL,
range
tissue
physical
The
in
and
hexactis, on
of
Tectura
the
average
feeding calories
sizes
may
thaidid
ranked drilling
thaidid
clearly
diet
snails
as
terms
trend
1974; 1983)
1982;
1973; et
1938;
shell
1985,
This from
most
enig
bar
data
prey
sta
con
lim
low
the
and
not
In
al.,
al
of
is
et be
of
of
a
the
to petta
creases
“optimum”
species,
a
limpets
scutum
6.9
have captured.
hypothesis
may
species
havior,
two gled
available
scutum)
larger the
Tectura (Figures The Size-frequency
varies
the
5
does available
(MORRIS could
greater
ample,
occurring
have
to
larger
Differences
account
of
Three
but
size
mg
duration
densities
30
20
10 40
50 species
DAYToN,
lack
on
should
a
differ
been
reach
considerably
limpets
have
not
may
(23%
larger
of
computed
with
range (2)
and actually
although
the
scutum 2.5
than
size
2a,
hypotheses
of
to
or
I
the
et
for
eaten
for
on
due
am
prey
for
in
of
differ data
shore.
may
smaller
be differences
a
(2) resulted
b);
at.,
larger
increasing
of
same
that
in
7.5
assuming
body
the
of
distribution
of the
the
these
1971),
larger
their
more
to
limpets
not
eaten
to
hence,
shell
these
that
on
by
both
size
limpets
1980),
differ
the
observed
study.
in differences
from
eastern
of
a
12.5
Limpet
among
shell
aware
mass
availability
dry
0.
prey
0.
their
relative
desirable
could
larger
thickness,
L.
(HUGHES, but
by
energy
average
either
species
maximum
two
lurida,
larger
lurida
in
MENGE of
in
mass
pelta
(1)
Figure 17.5
Ocenebra
prey
length but
species.
where
data
for
of
food
the
of
habitats.
the
the
species
shore
account
Shell
pattern
size
limpets
from
that
vulnerability
a
average
were
any
per
limpets
in
because
sizes
for
some
(Figure
22.5
size
on
size,
as value,
same
success
given
however,
notwithstanding,
were
the
differences
[l972}).
than
1980).
8
Length
of
Lottia
a adult
lurida
prey
sizes
the data
unit
eaten
differences
are
of
selected.
for
of 20-mm
On
of
(Lottia
27.5
as average
Turn
shell
or
comparable
were
shell
T.
Lottza
they
size
handling
consumption.
this
quite
8),
of
and
were
the
to
handling
nearby
it
at
pelta,
(3)
size
by
(mm)
scutum
seem
On
32.5
some
address
does
Turn
pelta
such
length,
difference
consumption
Island.
most
of
length
were
larger
the
hence to
limpet;
Tectura
in
not
size
pelta:
similar
than
this
however,
both
attack
more
in
Turn
two
maximum
37.5
Page
and
above escape L.peita
T.
differences
Island
presented.
likely
times
eaten
intermin
of
time
however,
for
eaten
the
0.
basis
the
than
the
scutum
L.
For
(1)
species
8.5
limpets
species
scutum
Tectura
likely
Over
lurida
(table
Rock,
42.5
both
could
once
petta
first
sizes
two also
de
over
199
the
was
for
be
the
vs.
do ex
L.
T.
to of Page cle a/., in consistently of /urida vulnerability time scutum observed ences lead size thickness
CLINT0cK, on This Ocenebra eaten correct, ably, size this sence would pets lurzda length (the microstructures
vulnerability A a
Both
thickness
than
1981),
decreased
estimate to eaten
to
eaten
predicted
overwhelmed
thicker
difference the
of noted
was
is
(that
200
an
(Figure be
of which
Lotlza
the
just
direct case;
thickness, determined the regressions Comparison these maximum Tectura
for
observed
lurida near increased
20
roughly
were in approximately
then
1967);
thicker size
maximum above. maximum
at
Fo/in medial
by
mm see shell,
remains
this
lines
pc/ta food
a
evidence
the
the
value
2b).
based
exceeding for
the may
is
detected scutum Figure
limpet
ices
size shell
hence, 17 difference
apex size
(shell-structure
pedal on
value
300 indicate of
shell
the
handling to on
which
and
Furthermore, expected
of
by
mm
drill.
on R. ranges when
the tentative. size
range
the
of
shell
2a) depth length;
the E
benefits rJ
iim
comparing the
for
is
(Figure
medial
Tcctura
B.
shell microstructural
for vulnerability
retractor based
(10—20
pedal
of
20
the the order 600 vulnerable 500 400 and
300 200
100
the
unsuccessful other Assuming Lowell depth
drilling (Figure thicknesses
L.
vulnerability
is in
time
from mm;
to thfferencc
thickness
depth
maximum
if
pc/ta
on Figure shell
approximately
retractor
the to
of
scutum
9). this which
of
mm),
“pallial”
and hand,
to the
muscle,
[unpublished
if Loltia the
Figure
maximum 3
5 A
bivalves; length
to if
maximum 9)
which
group this
of
pedal
mm
mm
hence
to the
9). thicker that
medial which
tissue
for 0. may
Lottia
Lottia
have muscle. in
differences attacks,
may S pc/ta
of
a
size
interpretation
Rather
longer
thickness). of
/urzda
2a).
based to in maximum
given
a
the it retractor
T.
it
be
KITcHELL L. 1 pc/ta a
similar
mass 8 of can to 12.5-mm
shell
also
could shell to size scuturn pc/la
size 7
given
dataj), calculated.
In
maximum mm
Horizontal pelta
of
the
Limpet T.
mm
a
handling however.
can
on
remark sized
drill
L.
of T.
was
Tectura
the
of
scutum
reduce
differ
would length
would
NIAC pedal
result
has 10
based
vulnerability
mus
sized pelta
scutum having to shell shell shell
drill
lim
Apical—shell
size
ab estimated
(as
0. 0. a
Figure
et
is
a
given retractor
Shell ______
and
the
vertical
sized
pc/ta
9 whose species. bachrnanz than consumption not same compared Attack different mechanical prefers sistently Second, of these similar separate for also the shores ular, neb7a for similar between (Hacmatopus First,
Length
was
muscle
Two
Compared
the
thickness
posterior
by account T
Ocenebra
determined
on
may
T. —a
medial
size
when
/urtda lines
pedal
scutum
FRANK peaks
differences (BLAcK,
scutum
to Behavior
larger
patterns additional data
feeding
these on
for
modes areas to
(mm)
have
and
20
preferences
that
illustrate
properties
at
a r
for shell
the
apical
pallial
two attacking
used
retractor
region of
lurzda
of
bachmanz)
and
20-mm to
apex
than
Occncbra
two
an
T. (approximately of
(1982) by
G.
of
differences
Tcclura
other
of order 1978).
species by
of
thickness
energetic
whose Dzcathazs very
scutum the
M.
shore,
(approximately
in
pieces
attack
species of
The
of
L. how size
H.
Tectura
thickness
shell;
the of the limpet
muscle
would Branch
of pc/ta. /
similar limpets,
reports
}
of
Both
bachmani,
scuturn
consume
/unda
the
the
preference
upper
pallial
Veliger,
limpet
5
indicate of than
of flesh
limpets
apical
(12
of
pallial—shell rather
in
acgrota
to
shell
scuturn: expected
information these
and These
seem
limpet.
species
(Figure
vulnerability of (unpublished
mm
seem modes
10
10
to
L.
weight-shell
30 that
and
its
the shell
or
L.
barnacle 12.5 (computed
than
a
mm
vs.
pc/ta.
two
yield that
based
most
of
if
foot
behavior
larger limpet’s
pc/ta
exhibited
data,
Vol.
lower
unlikely
difference
black
attack
within 14 20
of
Western
mm
3).
a
shell
predators.
given
H.
thickness
mm
simply mm
attack. mechanical
selectivity on
The
suggest to
As
taken
in
size
31,
predators,
limits
shell, bachmani
between from oystercatchers
apex observations),
a preferentially
the length
was
shell this
length
suggested
is the
to
smaller
remarkably
by in
than
Australian
No.
accounted
In perimeter
strikingly
be
from
radically
are
both that
length).
Rather,
partic
due
curves
larger
Lottta
ratios
basis.
these
3/4
con
0cc-
also
size
five
the
H.
by
to UNDERwooD. predators types Obtained the cles. hole. Biases lurida opercular where, the drill 0. Second, riphery though plates through occurred number discussion (HART limpets significantly differences cera. 1983). another permit fact, to predator sively terior observed gonad posterior distance consumption hole, consumed relation to consume energy-rich moribund digestive in the risk
Black, A. Although When The lurzda the That additional the the proboscis. In holes
substratum, R. may not of These produces portions (20 to foot. in more in and these such this observation foot all the & even compared of them being of advantage the
preferentially to Palmer, the attacking be observed from (Figure viscera consumed to create Feeding gland. at plates of cases of all were PALMER, the the prey. behaviors purely digestive presumed in the differences manner, gonad the able (Table such drill immediate Low regions where 41) more tissues observations observations (Table 1983), time the handling was Coupled dislodged flesh barnacle’s the of site a anterior not where biases even Because occurred they being to and biases hole narcotizing 5) tissue the to Tide and likely as and feeding Observations not to barnacles, shell of that tissue
enlarged 1988 retain first, 3) 1987; gland to barnacles the larger suggests make the 5): in adaptive a the also though attack, would foot than digestive in in at consumed effort be is quite access see the times with function end data limpet nearly common before to when to flesh handling the the snails preferential due had suggest at do skeletal consumed. had PALMER, its because would FAIRwEATHER at up ones the have the limpet of regions benefit margins “apparent” enough obtained required the but that not so toxin low because they hold to Ocenebra been in may only value the been from distance half the feet which gland foot losing (Table the simplistic. been of few the part with to appear be rather Ocenebra tide viscera. times wall upon had limpet consumed, they was of be which were about energy-rich proximity completed a from of 1982). is of between to actual consumed of were This observations all consumption drill greater drill for completed to to consumed hold (FAIRwEATHER thaidid such less plate 4; permit been lurida from plates (PALMER, for may smaller diet enlarge larger attacks strongly consumed their & Ocenebra to consuming for Yet 15% releases relaxes consumed holes limpets would different than First, lurtda UNDERwooD, If order a of be overlap of the drilled an be distance behavior the rather exhibited I most tissue because gastropods to passage their anatomical of intertidal commonly limpets before biased gonad at extensive unable drill were the on than from without the of drilling that the may, provide barna gaping lateral run 1982). where lurida hold of of exclu small prey tissue else drill even once- than prior these were hole drill pe the vis not an and the 0. & the the the lies the of by in to a of to bicostatus, barnacles sidered thtca D’ATTJLIo ences. 0. to contrasts were periments (1949) ornaturn) and when (=Venerupzsjaponica) valves, anomiid GRAHAM, eririacea PIER0N, ing inornalum CHAPMAN distributed the CARLT0N, ORT0N, species species conclusions, were of Ocenebra regression Comparison pets tidal emersion drilling servations dom Because likely proportion to based ure likely effect attacking (Table was Individuals japonica barnacles The Rather Ocenebra completion (Tapes, European 36.5% and 6a). of earlier given with not immersion, significant In on to who on to “barnacles, are of paucity to comparable 4). also 1929), 1933) larger Cltnocardium bivalves” have oysters Netarts feeding and with lurida (Chthamalus the than significant a were shorter reflect limpets 1962:516). Ocenebra. than analysis & respect for (SQuIRE, by [1976]) known Gardium, a in 1979) reported be respectively) of In pattern and choice, but consumes observed BANNER, than B. of of the been 0. drill Lota RADwtN smaller in addition, the and does Ceratostoma much revealing and limpets the tintznabulum) of appear Diets (Figure the mussels erinacea Ocenebra larger Bay, larger the NE handling 0. suggest to to revealed completed conclusions are and smaller, small published hole Japanese epifaunal both not appear Mercenaria, 1972 the that size Because ,beita extensive statistically prey both japonica time less For challengerz, were Pacific diet. nuttalit ones Oregon. other 1949; with reported to compared possibly 0. consistent & completed western for unfinished Myttlus oysters 6 than (CHEw in a tubicolous (BARRY, [cited on be that well suggest predator lurzda 0. legend). lurida since Although size times D’ATTILIo (Figure eaten to that ones the a Other prey inornatum a considered commercially of japonica via on Ocenebra and data form differ (Pecten; less consumption oysters longer such (CHEw designed of the bias in both laboratory, their Faphia; were smaller to edulis Pacific incidental for were an Crepidula more & for initiated (Figure Balanus including mussels to CHAPMAN desirable that CARLT0N. 1981; with (Figure eat the 6a) precludes bivalves Species drill and from biases in EIsLER, worms, attack smaller of small either drill status eaten time and PIER0N, interrupted handling (20.9%) lurnarza frequently bulk and (Ceratostoma 0. several these [1976]). & to prey the limpets, by HANCOCK, HANcocK, to (but holes the holes trigonus, lurida (PvItilus 6b). attacks had be Ta,besJaponzca EIsLER, grown limpets. detect that, 6) introductions; prey both limpet in but (FRE’rFER prior was Macoma of of bias as RADwIN diets mussels relationships limpets 1958). 1979:384]). size, C’eratostoma now & very seems preference were
the Page limpets species little (also pests, were when Multiple- 1933) their times, following Ocenebra had this BANNER because, burrow initiated. expected of oysters: prefer (42.6% to on diet widely the at edulis B. species strong 1960; 1958; 1960; This other if closer con trend more (Fig more bat been tidal lim and ran
ex 201 two at bi in all any ob of & of the by & a/us and incidentally growth tel/a they that et adults, reported. laboratory, erence lOris/a, Chihamalus, on rates (p. as of cobble worms.” in ports
served resentative Page genera mit 4.25/m2 higher Island), rather 0. (1982) the erablv indeed scattered be further Ceratosiorna intertidal (approx. thickness oratories supported mond. usual reviewer were presented Research I Lowell thank a/. As These any the a Ba/anus relatively purpunoides 750). diet Scpttfer little whole. over penita hatchlings appear (1974) some and provided in girdle patience other only
202 while to comparable among both report and R. densities: high and (TAYLOR field also of the any I on to unfortunately 1—3/rn 2) Similarly, mussels. for individuals Similarly, 3Iti/us for support shores. regressions natural B. from in glandula 0. have anecdotal survival, the and be I laboratory vzrgaius) and inornatum a director Ocenebrajaportica boulder feeding the of who to however, densities young studies. generously initiated local uncommon this the Lowell, lurida anecdotal their ACKNOWLEDGMENTS subtidal said the Cryptochiton by diet and consume NSF when were which Lithophaga normally diet ci SPIGHT use noted paper Subtidally, and while NSERC (LUCKENS. different densities Finally, field here densities al., snails and comments I good is Fo’rHERINGHAM although observations, and when although habitat grant observations of at have of observed this D. given used really of (RADwIN barnacles observations no rock meagre 1980) that appears observations except M. study, laboratory a were writing the boring provided staff here. humor. et ‘N. 0. “occasionally study field density encountered these OCE-74-02307 reported edulzs TALMADGE Operating to al. wall. ste/len, species a for barnacles plumula; unusual in lunida eastern on Phillips. diets providing however, choice and collected of 1970a). create that, I providing on Although (1974) data, to observations a both specifically bivalves & are cannot and and to Cape the were and relatively and of well consume the 0. the D’ArrlLIo, appear facilities of but of like at feed is made for (1971) 0. diminished Friday they mussels publication lumarza 0. Pacific Figure for
J. feeding KILBuRN p. were reported Ocenebra. and for Grant report unpublished manuscript. this Except Beale less feed lurida makes (1975) while they the 0. extensive many be inierfossa Geller, primarily the 743) I data on prefer available Ocenebra to an to have sure lunida South mentions because than wave-exposed intertidal on eaten newly Harbor and of genus may are 9. “small vary 0. happened A7245. R. a rasping by A.R.P. (Vancouver muricacean anonymous no on at 1976), barnacles” merely for by density diet & The how T. further L. poulsoni; since Whether Chiharn expenses correctly 0. for I mention least data in African only SPIGHT growth achieve /m2 RIPPEY consid and settled noting awaits (Pent Paine. Ham in loris/a loris/a R. of shell- were pref Lab only their tube data rep per was pits site the ob the re on on 0. as as B. to of if BERRY, CARLT0N, BARRY. BLACK, CHAPMAN, BRANCH, DAYToN, BRooM, CHEw, FAIRwEAi’uER, FOTHERJNGssAM, FAIRwEATHER, FRANK, DixoN, K0zL0FF, KITCHELL, KILBURN. HART, FRETrER. HUGHEs. HANCOCK, granosa edo/is Jour. honzutn coast growth Co. the energy (Naticidae: diet of State introduced Biol. Jour. gastropods of feeding California, of black margina/ba. California nity note Biol. Mar. Carpenter 351—389. tests Oceanogr. Preliminary and Thats 511 Northwest. luscs. 552. Macmillan 1981. 143. 1362. space their the M. K. M. R. life W. A. P. Galwav. of pp. heritability M. organization: and on G. R. Ann. 46:157—162. P. oystercatchers, of of R. Biol. (L.), Fish. V. cariinfera J. Exp. Ray K. E. D. D. ‘N. W. W.
J J. edible predators history
J. habits Prey flow, uesttarzum 1978. (L.). of other M. prey. K. Washington, in N. North .A.,
J. & application & & N. A. 1979. (Prosobranchia: & P. P. Press: M. Mar. a the Society: marine in Rev. 1981. 1983. Shaskyus Gastropoda) Ecol, E. 1982. Davis. South Mar. Res. 1982. Mar. Univ. A. LITERATURE R. investigations 1971. 1980. rocky 1981. N. Jour. 1982. G., selection C. Irish A. C. Kilkieran and Oecologia mollusc. of enemies RIPPEY. 1960. of 1987. Tactics & gastropods GRAHAM. America, EIsLER. (Lamarck) &A.J. of the 19:235—380, R. H. A. Biol the Bd.
The 64:71—89. and History, 1971. Berkeley. A. Biol. Ecol. Distribution BMDP Africa the Washington ecological (L.) 904 and Predation intertidal Fish. drill Effects Exp. London. J. Optimal The Competition, PALMER. Haematopus Japanese B0GGs, festivtis Japanese to Size-selection, H. Canada The biases Dept. UNDERwOoD Ann. Marine provision of the by of estuarine pp. Proc. Ecol. on 1982. UNDERwooD. Progr. and Veliger, site upon 56:169—179. biology BANNER. Life Invest. Mar. 1958. Ph.D. Ltd.: the whelks ecology naticid biogeography, of Muricidae). statistical fossil 1962. .Vattca of a preying Rev. due J. Fish. Bertraghbov selection (Hinds) 755 community. foraging predation Olympia Malaysian 107:101—120. interactions. Malacol. history by winter oyster 15:529—535. the drill, Sea 1987. and Ser. Johannesburg. Biol. F. invertebrates Press: bachmanz. record. (Ser. A Dissertation, of to and CITED invertebrates pp. Natica trocharean preying 18:423—481. disturbance, British gastropods: maculosa Biol. KITCHELL of shells preliminary limpets: ecology different 1949. & 17:143—156. consumption Vol. Tritonalia on drill, software. Ecol. the subsequent and patterns feeding in B) in Stereotypy, M. Seattle, oyster, Ecology by 1983. Soc. the Paleobiology Bull. the thaidid maculosa of molluscan 24:1—18. shore, and Ecol. bays,
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Contributions 31, southern physical bivalve (Lamarck) marine MoN. Lond, handling gastropod oysters. & japan/ca, 49A:169—200. limpets. of on ecology whelk The University of experimental University Ostrea of 249 and Washington. Connemara, Monogr. 52:742—757. study
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No. gastropods. the limpets the the utilization rates ontogeny, 63:1352— Lamarck apparent A. pp. commu Anadara poulsoni 34:123— enemies context. factors, Morula Africa, littoral 7:533— Pacific Pacific lurzda. Ostrea of of RICE. 1984. times Mar, Mar.
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LOUDA, LINDBERG, A. ertnacea. Stanford. tertidal gastropod eral predator Mar. Life visually ator-mediated Veliger to patchiness Ecol. knysnae’isu win. intertidal Hist.. lerophontoid of Tohoku Asamushi. :a!ata. riod snail
Veliger R. Island. actual
Ocenebra J. species H. R. B. lvi. S. B.
of Palmer. history Jour. Biol. Monogr. Scai-ic,ia P. H. Yale P.. Oecologia C. A. K. the M. H.. B. invertebrates A. I). cryptic, 16:87-92. Puget
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