Balanus Glandula Phylum: Arthropoda, Crustacea Class: Thecostraca, Cirripedia Order: Thoracica, Sessilia Acorn Barnacle Family: Balanidae

Home , Balanus, Balanus balanus, Balanus glandula, Balanus trigonus, Lottia digitalis, Semibalanus cariosus

Balanus glandula Phylum: Arthropoda, Crustacea Class: Thecostraca, Cirripedia Order: Thoracica, Sessilia Acorn barnacle Family: Balanidae

Description plates themselves include the rostrum, Size: Up to 3 cm in diameter, but usually less opposite it the carina and between the carina than 1.5 cm (Ricketts and Calvin 1971; and rostrum are the four side plates, the Kozloff 1993). carinolateral and rostrolateral plates (see Color: Shell usually white, often irregular and Plate 213, Newman 2007). color varies with state of erosion. Cirri are Opercular Valves: Valves consist of black and white (see Plate 11, Kozloff 1993). two pairs of movable plates inside the wall, General Morphology: Members of the which close the aperture: the tergum and the Cirripedia, or barnacles, can be recognized by scutum (Figs. 3a, 4, 5). their feathery thoracic limbs (called cirri) that Terga: The terga are the are used for feeding. There are six pairs of upper, smaller plate pair and each tergum has cirri in B. glandula (Fig. 1). Sessile barnacles a short spur at its base (Fig. 4), deep crests are surrounded by a shell that is composed for depressor muscles, a prominent articular of a flat basis attached to the substratum, a ridge, and an articular furrow (Pilsbry 1916). wall formed by several articulated plates (six Scuta: The scuta have pits on in Balanus species, Fig. 3) and movable either side of a short adductor ridge (Fig. 5), opercular valves including terga and scuta fine growth ridges, and a prominent articular (Newman 2007) (Figs. 2, 4, 5). ridge. Shell: Aperture: The shell opening, from Shape: Shell surrounding the which the cirri emerge when feeding, is barnacle body is pyramidal in shape (see Fig. controlled by movement of the terga and 99, Kozloff 1993) (Fig. 2). scuta in conjunction with adductor and Basis: Calcareous and flat, attached depressor muscles. When closed, plates to hard substrate, rendering B. glandula a produce a distinct and sinuous line at their sessile, or attached barnacle junction in B. glandula (Kozloff 1993). (Balanomorpha). Cirri: Feathery, black and white and Wall: Formed by the six plates (Fig. conspicuous. Each of the six pairs of legs 2) and composed of irregular, vertical, filled (=cirri), bears 4–7 pairs of setae (Nishizaki tubes, giving the exterior the appearance of and Carrington 2014). The cirri of B. glandula rough ribbing. were the first observed to exhibit Longitudinal Tubes: Only ecophenotypic plasticity, where individuals present in immature individuals (Newman adjusted response time (i.e. cirral withdrawl) 2007). to specific habitats. An adjustment from one Plates: Calcareous, nearly habitat (e.g. wave-exposed) to the next (e.g. conical and columnar. Six in family protected) occurred over a period of two molts Balanidae. Each plate is composed of (approximately 18 days) (Marchinko 2003). parietes (exposed triangular part) (Figs. 3a, 3b), alae (the plate overlapping plate edges) Possible Misidentifications and radii (the plate edge marked off from the There are three groups (i.e. superorders) of parietes by a definite change in direction of cirripeds including the Rhizocephala growth lines) (Fig. 3b) (Newman 2007). The (parasites among crustaceans), the

Hiebert, T.C. and M. Jarvis. 2015. Balanus glandula. In: Oregon Estuarine Invertebrates: Rudys' Illustrated Guide to Common Species, 3rd ed. T.C. Hiebert, B.A. Butler and A.L. Shanks (eds.). University of Oregon Libraries and Oregon Institute of Marine Biology, Charleston, OR.

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12694 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to [email protected] Acrothoracica (shell-less burrowing forms), B. crenatus or B. glandula. Generally, these and the Thoracica. The Thoracica contains latter two species are found higher in the 1,000 species worldwide including the intertidal than is S. cariosus, which occurs monophyletic taxa, Lepadomorpha, the mostly subtidally. stalked barnacles, and the Balanomorpha, or Balanidae encompasses the genera sessile barnacles (Perez-Losada et al. 2008; Megabalanus, Paraconcavus, and Chan et al. 2014). Among the sessile forms, Menesiniella (each with one local species), there are four families represented locally. Amphibalanus (three local species) and The family Chthamaloidea includes members Balanus (four local species). Balanus of the genus Chthamalus. Juvenile Balanus crenatus is generally found in the intertidal glandula and Chthamalus dalli, often found at a lower level than the ubiquitous and together, are very alike. The genus morphologically similar B. glandula. Chthamalus has alae on its rostral plates, not Balanus glandula has no longitudinal wall radii (i.e. the rostral plate is overlapped, tubes (except when young) and it differs in rather than underlapped, as in B. glandula, the structure of terga and scuta: the terga by the rostrolateral plates). Chthamalus dalli are very wide and have longer spurs and is found both with and at higher tide levels the scuta have no adductor ridges (compare than B. glandula, and individuals are usually Fig. 5 with B. glandula Figs. 4, 5, this brown. The family Tetraclitoidea has one guide). Balanus crenatus, on the other species locally (Tetraclita rubescens), and is hand, has a shell wall with a single row of characterized by a wall that is composed of uniformly spaced tubes (Newman 2007). four plates (rather than six in the Balanidae). Balanus crenatus is a difficult barnacle to The remaining two families are the identify: "Not only does every external Balanidae and Archaeobalanidae. The character vary greatly in this species, but Archaeobalanidae includes the genera the internal parts very often vary to a Armatobalanus, Conopea, Hesperibalanus surprising degree, and to add to the and Semibalanus (each with one local difficulty, groups of specimens do not rarely species). The latter genus includes a vary in the same manner” (Charles Darwin common local intertidal species S. cariosus in Cornwall 1951). Balanus nubilus, the (and former member of the genus Balanus). giant acorn barnacle, is easily distinguished An isolated S. cariosus, is with splinter-like from B. glandula by its large size, reaching spines, nearly black cirri and is not likely to be 100 mm in diameter, and a shell aperture confused with another barnacle. It has a that is relatively large and flaring (Newman thatched appearance, being irregularly ribbed 2007). Balanus trigonus is a lower intertidal and its walls have uneven, longitudinal tubes species with a southern distribution (to (Pilsbry 1916). However, where it is crowded Monterey Bay, California). or eroded, these spines may be worn off or not developed, and the barnacle would have Ecological Information to be distinguished from other common Range: Type range includes Alaska to Baja barnacles by its terga and scuta, and by its California (Darwin 1854), B. glandula was unique and unusual membraneous base. introduced to South America (Argentina) and Semibalanus cariosus have terga with a long Japan (Kado 2003; Newman 2007; Rashidul pointed spur, quite different from either B. Alam et al. 2014). crenatus or B. glandula. Semibalanus Local Distribution: Ubiquitous in a wide cariosus commonly co-occurs with B. variety of locations from the open rocky crenatus, B. glandula, as well as with shores to the salty or brackish bays of the Chthamalus dalli. Juvenile S. cariosus will Oregon coast (Kozloff 1993), where show a typical heavy ribbing and starry basis populations show genetic heterogeneity over outline, which would distinguish it from young great distances (Barshis et al. 2011), except

in central California where gene flow is more Life-History Information restricted between populations (Sotka et al. Reproduction: Cirripeds usually brood their 2004). eggs and B. glandula produces 2–6 Habitat: Very adaptable to a variety of broods/year, in winter and spring (Oct–May in habitats. Suitable substrates include rocks, southern California), and through September pilings, wood, other crustaceans, molluscs, on Vancouver Island and December in Friday and barnacles. Often in conditions with Harbor (Høeg et al. 1987). Barnacles are one extreme exposure to sun, wind, rain and can of the few sessile organisms with internal tolerate estuarine conditions quite well, fertilization and plasticity in penis length has including those of poor water circulation, low been observed, with shorter penises in high oxygen, and little wave action (Ricketts and wave-energy environments (Neufeld and Calvin 1971). Populations in polluted areas Palmer 2008). Individuals are hermaphroditic have been shown to exhibit lower genetic and self-fertilization is possible, but not diversity, with more individuals of the same common (MacGinitie and MacGinitie 1949; haplotype (southern California, Ma et al. Yonge 1963). Spermcast spawning can 2000). occur (Barazandeh et al. 2014). Eggs and Salinity: Collected at salinities of 30, but can embryos are retained in ovisacs within the also survive at lower salinities (Ricketts and mantle cavity and are discharged as nauplii Calvin 1971). Balanus glandula resists after four months (Yonge 1963; Høeg et al. desiccation better than other Balanus species 1987; Arnsberg 2001). Ascorbic acid in water (Newman and Abbott 1980). stimulates copulation (R. Boomer personal Temperature: Survives a wide range of communication). For detailed reproductive temperatures, but optimal temperatures for anatomy see Høeg et al. (1987). feeding range between 10˚ and 15˚ C Larva: Cirriped broods hatch as nauplius (Nishizaki and Carrington 2014). larvae and undergo 4–6 naupliar stages, each Tidal Level: One of the most important larger and more setose than the last (Høeg et zonation indicators as very small barnacles al. 1987; Arnsberg 2001; Chan et al. 2014). often settle high in the dry uppermost Fewer setae occur on the antennae rami and intertidal zone, below Littorina (Ricketts and mandibles in B. glandula nauplii beyond stage Calvin 1971). Individuals are most common I than is seen in congeners (Brown and in the high to mid-tide zone (Darwin 1854) Roughgarden 1985). For naupliar setal and their upper limit appears to be set by formulae and antenna morphology, see substrate temperature as S. cariosus and B. Branscomb and Vedder 1982. Larvae molt to glandula individuals showed a negative the second naupliar stage shortly after correlation in abundance with substrate hatching (Branscomb and Vedder 1982). The temperature in the mid-intertidal (Salish Sea, generalized cirriped nauplius has a triangular Washington, Harley 2011). or shield-shaped carapace with frontolateral Associates: Forms dense clusters with horns and a conspicuous naupliar eye (Fig. 1, Chthamalus dalli, Nucella, mussles and Arnsberg 2001; Figs. 22.1–22.2, Chan et al. limpets (including Lottia digitalis) at high tide 2014). In B. glandula, the nauplius has levels (Kozloff 1993; Newman 2007). curved frontal horns and a 3-lobed labrum Sometimes found on larger Balanus cariosus (Brown and Roughgarden 1985; Figs. 4 and individuals. 7, Arnsberg 2001). The first naupliar stage Abundance: One of the most abundant lasts less than an hour and stages 4–6 are animals on the coast with up to 70,000 recognizable by a pair of well-developed individuals per square meter (Ricketts and dorsal carapace spines (Arnsberg 2001). The Calvin 1971). Larval abundance can also be sizes of B. glandula nauplii begin at 271 µm high in the plankton, where 10 cyprids per (stage I) and end at 745 µm (stage VI) (Brown 200 liters were reported in central California and Roughgarden 1985). The final larval (Gaines et al. 1985). stage in cirripeds is called a cyprid, a non- feeding stage that attaches to a substrate by its antennae, secretes a cement and builds

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12694 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to [email protected] the adult calcareous shell (Ricketts and Longevity: 8–10 years (Newman and Abbott Calvin 1971). Cyprids are oblong and 1980). composed of a bivalve shell, six thoracic Growth Rate: Cirriped body growth occurs in appendages, a pair of compound eyes and a conjunction with molting (Kuris et al. 2007). conspicuous lipid reserve anteriorly (Fig. 3, Shell growth proceeds as follows (basal Arnsberg 2001; Figs. 22.2–22.3, Chan et al. diameters): 7–12 mm in first year, 10–16 mm 2014). Cyprids prefer rough surfaces for by the second year and 14–17 mm by three settlement (Yonge 1963). Cyprid larvae in B. years (Newman and Abbott 1980). Adults glandula are golden in color and have a under high densities form “hummocks” where distinct carapace shape and surface that is individual barnacles grow tall and form tightly- dull and decorated with papillae and four packed columns (Bertness et al. 1998). Shell pigment patches, they are 640–780 µm in size (e.g. terga and scuta) may correlate with length and can be observed in the plankton temperature (Barnes and Healy 1969). Those year round except in winter months (Fig. 8, B. glandula that settle at lowest tidal heights Arnsberg 2001). The pelagic larval duration grow fastest in the first year, but after that, in B. glandula is estimated at 3–4 weeks those higher in the intertidal exhibit the fastest (Brown and Roughgarden 1985). Larval growth (Yonge 1963). settlement is effected by degree of coastal Food: Filter or suspension feeders (Nishizaki upwelling, where more settlement is observed and Carrington 2014), barnacles eat plankton in years when upwelling is weak and larvae and some detritus, that is strained from stay closer to shore (Connolly and incoming currents by several pairs of Roughgarden 1998; Barshis et al. 2011). hydrostatically-extended thoracic appendages Most larval settlement occurs in spring and called cirri (Fig. 1) (MacGinitie and MacGinitie autumn in Friday Harbor, Washington (Høeg 1949). et al. 1987), but may vary with sea Predators: Snail Nucella at low tide levels, temperature (e.g. January–June, Santa as well as sea stars, worms (particularly on Barbara, California, Connell 1970). Where juveniles), birds and occasionally humans cyprids were abundant in the water column, (e.g. Northwest Native Americas). Three snail settlement occurred at a rate of 2 cyprids per species, Thais emarginata, Thais canaliculata square centimeter of available space (Gaines and Thais lamellose, are also common et al. 1985). Like other marine invertebrate predators of B. glandula and S. cariosus larvae, the cyprid larvae of S. cariosus and B. (Washington, Connell 1970). Furthermore, it glandula become concentrated in has been suggested that predation by this convergence zones over internal waves, genus of drilling gastropods has driven the which provides a mechanism for shoreward evolution of balanomorph barnacle plate transport of larvae prior to settlement (Shanks morphology (Palmer 1982). Predators on B. and Wright 1987). glandula larvae include many plankton Juvenile: Newly metamorphosed juveniles feeders (e.g. fish, MacGinitie and MacGinitie can be found settled in the intertidal from -0.6 1949). meters to -0.3 meters and have six pairs of Behavior: Adults exhibit anti-predatory setae situated near and around the opercular hiding behavior (i.e. withdrawl of cirral fan) in opening (Høeg et al. 1987). The shell wall in response to shadow (Dill and Gillet 1991). juveniles consists of empty vertical tubes, Cyprid larvae can actively search out settling which only become filled and irregular in the area by “walking” on antennules, and adult adult. Individuals from the upper tidal levels distribution is at least in part determined by reach sexual maturity and spawn during their these pre-settlement behaviors and zonation second year, while those from lower areas do in the plankton (Grosberg 1982; Gaines et al. so in their first year (Yonge 1963). 1985).

Bibliography CHAN, B. K. K., J. T. HØEG, and R. KADO. 2014. Thoracica, p. 116-124. In: Atlas ARNSBERG, A. J. 2001. Arthropoda, of crustacean larvae. J. W. Margtin, J. Cirripedia: the barnacles. In: An Olesen, and J. T. Høeg (eds.). Johns identification guide to the larval marine Hopkins University Press, Baltimore. invertebrates of the Pacific Northwest. CONNELL, J. H. 1970. A predator-prey A. L. Shanks (ed.). Oregon State system in the marine intertidal region. University Press. I. Balanus glandula and several BARAZANDEH, M., C. S. DAVIS, and A. R. predatory species of Thais. Ecological PALMER. 2014. Where even a long Monographs. 40:49-78. penis can't help: evidence of long- CONNOLLY, S. R., and J. ROUGHGARDEN. distance spermcast mating in two 1998. A latitudinal gradient in acorn barnacles. Journal of northeast Pacific intertidal community Experimental Marine Biology and structure: Evidence for an Ecology. 454:49-54. oceanographically based synthesis of BARNES, H., and M. J. R. HEALY. 1969. marine community theory. American Biometrical studies on some common Naturalist. 151:311-326. cirripedes. II. Discriminate analysis of DARWIN, C. 1854. A Monograph of the measurements on the scuta and terga subclass Cirripedia (Part II Balandiae). of Balanus balanus, Balanus crenatus, Royal Society, London. Balanus improvisus, Balanus glandula DILL, L. M., and J. F. GILLETT. 1991. The and Balanus amphitrite stutrsburi, economic logic of barnacle Balanus Balanus pallidus stutsburi. Journal of glandula (Darwin) hiding behavior. Experimental Marine Biology and Journal of Experimental Marine Ecology. 4:51-70. Biology and Ecology. 153:115-127. BARSHIS, D. J., E. E. SOTKA, R. P. KELLY, GAINES, S., S. BROWN, and J. A. SIVASUNDAR, B. A. MENGE, J. A. ROUGHGARDEN. 1985. Spatial BARTH, and S. R. PALUMBI. 2011. variation in larval concentrations as a Coastal upwelling is linked to temporal cause of spatial variation in settlement genetic variability in the acorn for the barnacle, Balanus glandula. barnacle Balanus glandula. Marine Oecologia. 67:267-272. Ecology Progress Series. 439:139- GROSBERG, R. K. 1982. Intertidal zonation 150. of barnacles: the influence of BERTNESS, M. D., S. D. GAINES, and S. M. planktonic zonation of larvae on YEH. 1998. Making mountains out of vertical distribution of adults. Ecology. barnacles: the dynamics of acorn 63:894-899. barnacle hummocking. Ecology. HARLEY, C. D. G. 2011. Climate change, 79:1382-1394. keystone predation, and biodiversity BRANSCOMB, E. S., and K. VEDDER. 1982. loss. Science. 334:1124-1127. A description of the naupliar stages of HØEG, J. T., P. L. LIIG, R. R. the barnacles Balanus glandula STRATHMANN, and D. S. WETHEY. (Darwin), Balanus cariosus (Pallas), 1987. Phylum Crustacea, class and Balanus crenatus (Bruguiere) Maxillopoda, subclass Cirripedia, p. (Cirripedia, Thoracica). Crustaceana. 370-392. In: Reproduction and 42:83-95. development of marine invertebrates BROWN, S. K., and J. ROUGHGARDEN. of the northern Pacific coast. M. F. 1985. Growth, morphology, and Strathmann (ed.). University of laboratory culture of larvae of Balanus Washington Press, Seattle. glandula (Cirripedia, Thoracica). KADO, R. 2003. Invasion of Japanese shores Journal of Crustacean Biology. 5:574- by the NE Pacific barnacle Balanus 590. glandula and its ecological and biogeographical impact. Marine

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12694 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to [email protected] Ecology Progress Series. 249:199- NISHIZAKI, M. T., and E. CARRINGTON. 206. 2014. Temperature and water flow KOZLOFF, E. N. 1993. Seashore life of the influence feeding behavior and northern Pacific coast: an illustrated success in the barnacle Balanus guide to northern California, Oregon, glandula. Marine Ecology Progress Washington, and British Columbia. Series. 507:207-218. University of Washington Press, PALMER, A. R. 1982. Predation and parallel Seattle. evolution: recurrent parietal plate KURIS, A. M., P. S. SADEGHIAN, J. T. reduction in Balanomorph barnacles. CARLTON, and E. CAMPOS. 2007. Paleobiology. 8:31-44. Decapoda, p. 632-656. In: The Light PEREZ-LOSADA, M., M. HARP, J. T. HOEG, and Smith manual: intertidal Y. ACHITUV, D. JONES, H. invertebrates from central California to WATANABE, and K. A. CRANDALL. Oregon. J. T. Carlton (ed.). University 2008. The tempo and mode of of California Press, Berkeley, CA. barnacle evolution. Molecular MA, X. L., D. L. COWLES, and R. L. Phylogenetics and Evolution. 46:328- CARTER. 2000. Effect of pollution on 346. genetic diversity in the bay mussel PILSBRY, H. A. 1916. The sessile barnacles Mytilus galloprovincialis and the acorn (Cirripedia) contained in the barnacle Balanus glandula. Marine collections of the U.S. National Environmental Research. 50:559-563. Museum; including a monograph of MACGINITIE, G. E., and N. MACGINITIE. the American species. U.S. National 1949. Natural history of marine Museum Bulletin. 93:1-366. animals. McGraw-Hill Book Co., New RASHIDUL ALAM, A. K. M., T. HAGINO, K. York. FUKAYA, T. OKUDA, M. NAKAOKA, MARCHINKO, K. B. 2003. Dramatic and T. NODA. 2014. Early phase of phenotypic plasticity in barnacle legs the invasion of Balanus glandula along (Balanus glandula (Darwin)): the coast of Eastern Hokkaido: magnitude, age dependence, and changes in abundance, distribution, speed of response. Evolution. and recruitment. Biological Invasions. 57:1281-1290. 16:1699-1708. NEUFELD, C. J., and A. R. PALMER. 2008. RICKETTS, E. F., and J. CALVIN. 1971. Precisely proportioned: intertidal Between Pacific tides. Stanford barnacles alter penis form to suit University Press, Stanford, California. coastal wave action. Proceedings of SHANKS, A. L., and W. G. WRIGHT. 1987. the Royal Society B-Biological Internal-wave-mediated shoreward Sciences. 275:1081-1087. transport of cyprids, megalopae, and NEWMAN, W. A. 2007. Cirripedia, p. 475- gammarids and correlated longshore 484. In: The Light and Smith manual: differences in the settling rate of intertidal invertebrates from central intertidal barnaces. Journal of California to Oregon. J. T. Carlton Experimental Marine Biology and (ed.). University of California Press, Ecology. 114:1-13. Berkeley. SOTKA, E. E., J. P. WARES, J. A. BARTH, R. NEWMAN, W. A., D. P. ABBOTT, R. H. K. GROSBERG, and S. R. PALUMBI. MORRIS, and E. C. HADERLIE. 1980. 2004. Strong genetic clines and Cirripedia: the barnacles. In: Intertidal geographical variation in gene flow in invertebrates of California. Stanford the rocky intertidal barnacle Balanus University Press, Stanford, California. glandula. Molecular Ecology. 13:2143- 2156.

YONGE, C. M. 1963. The Sea shore. Atheneum, New York.