Crustacean Research 47: 55-64

Home , Adamsia, Calliactis, Calliactis parasitica, Dardanus (crustacean), Hormathiidae, Sagartiidae

Crustacean Research 2018 Vol.47: 55–64 ©Carcinological Society of Japan. doi: 10.18353/crustacea.47.0_55 Transfer of the gatekeeper sea anemone Verrillactis sp. (Cnidaria: Actiniaria: Sagartiidae) between shells by the host hermit crab Dardanus deformis (H. Milne Edwards, 1836) (Decapoda: Anomura: Diogenidae)

Akihiro Yoshikawa, Ryutaro Goto, Akira Asakura

Abstract.̶ The symbiotic association between hermit crabs and sea anemones is a classic example of mutualism in the sea. Some species of hermit crabs have the ability to transfer the symbiotic anemones onto their new shells when they change shells. The hermit crab Dardanus deformis (H. Milne Edwards, 1836) (Decapoda: Diogenidae) carries some anemones on the dorsal surface of the shell (e.g, Calliactis) it inhabits and frequently has the sea anemone Verrillactis sp. (most probably conspeciﬁc with “Verrillactis paguri” in Uchida and Soyama, 2001) placed at the shell aperture. In this study, we observed that D. deformis transferred Verrillactis sp. from the aperture of its old shell to that of its new shell. This suggests that the peculiar position of Verrillactis sp. is determined by the hermit crab, which recognizes its proper position. Dardanus deformis engaged in a speciﬁc behavior of tapping before transferring Verrillactis sp. to the new shell. This is similar to the behavior shown previously by D. deformis to remove the sea anemones of Calliactis (Hormathiidae) from the dorsal surface of the shell. This suggests that this hermit crab species evolved a very similar tactile process for communication between the different Sagartiidae and Hormathiidae lineages of sea anemones.

Key words: Symbiotic association, mutualism, behavior, marine invertebrate, quantitative observation

■ Introduction and use of the sea anemones as emergency food (Imafuku et al., 2000). The symbiotic sea Many species of hermit crabs are known to anemones also benefit from their association carry symbiotic sea anemones on the external with hermit crabs in the form of access to food surfaces of the shells they inhabit or on their resources (Stachowitsch, 1979, 1980), ensured chelipeds (at least 41 species, 15 genera, 3 substratum availability (Conover, 1979; families of hermit crabs; at least 35 species, 14 Brooks, 1989), protection from predators, and genera, 7 families of sea anemones; Williams increased dispersal (Balss, 1924; Jonsson et al., & MacDermott, 2004; Antoniadou et al., 2001; McLean & Mariscal, 1973). These recip- 2013). The benefits for host hermit crabs in- rocal benefits have identified these relation- clude protection from predators, such as cepha- ships as “mutualism” (Antoniadou et al., 2013). lopods and fish, by the nematocysts of sea At least 24 hermit crab species have the abil- anemones (Ross, 1971; Balasch & Mengual, ity to transfer sea anemones to a new shell at 1973; Ross & Boletzky, 1979; McLean, 1983) shell change (Ross, 1974). Almost all the stud-

Received: 1 Jan 2018. Accepted: 5 May 2018. Published online: 26 Jul 2018. 55 AKIHIRO YOSHIKAWA, RYUTARO GOTO, AKIRA ASAKURA

Fig. 1. The symbiotic sea anemone Verrillactis sp. attached near the aperture of snail shells inhabited by the hermit crab Dardanus deformis (SL＝6.3 mm; female). (a), the original Neverita didyma hosoyai snail shell with Verrillactis sp. attached. (b), a Mancinella siro shell with Verrillactis sp. transferred from a Neverita didyma shell by the hermit crab (observation 1). (c), a N. didyma shell with Verrillactis sp. transferred from a M. siro shell (observation 2). (d), a Purpura panama shell with Verrillactis sp. transferred from a N. didyma shell (observation 3). (e), a N. didyma shell with Verrillactis sp. transferred from a P. panama shell (observation 4). (f), a N. didyma shell with Verrillactis sp. transferred from another N. didyma shell (observation 5). The scales indicate 5 mm. The white arrows indicate Verrillactis sp.

56 Crustacean Research 47 Crustacean Research 47 TRANSFER OF VERRILLACTIS SP. BETWEEN SHELLS BY HERMIT CRAB

ies of the transfer have focused on sea anemo- ■ Material and Methods nes on the external surfaces of the host shells or on the hermit crab chelipeds (Ross, 1975). One D. deformis (shield length＝6.3 mm; fe- However, one interesting example, the sagartiid male) was collected from an intertidal rocky sea anemone Verrillactis sp. (most probably shore at Hatakejima Island, Shirahama, conspecific with “Verrillactis paguri” in Uchi- Nishimuro, Wakayama, Japan (33°41′46.6″N, da and Soyama, 2001) is attached to the colu- 135°21′48.0″E), on 6 September 2017 (Fig. mella (inner lip) of the aperture of the gastro- 1a). We brought it back to our laboratory, kept pod shell carried by the hermit crab (Fig. 1). it in a running-sea-water aquarium, and fed it Predators, such as fish, brachyuran crabs, and once every three days (e.g., krill and fish fil- octopuses (Reese, 1969), often attack the aper- lets). We observed the shell exchange and ture of the shell to eat the chelipeds and ambu- transfer of sea anemones by providing intact latory legs of hermit crabs, so this placement empty snail shells of similar size to the shell of Verrillactis sp. on the shell aperture, might that D. deformis had first used; these shells protect the crabs from predators like a gate- were obtained from a tidal flat at Shinjocho, keeper. Tanabe, Wakayama, and from a rocky shore No quantitative study has examined how a around Shirahama Aquarium, Kyoto University hermit crab transfers this gatekeeper sea anem- (33°41′33.3″N, 135°20′15.8″E). We provided, one, Verrillactis sp., when the crab changes its in an arbitrary order, these shells to D. deformis shell, but one old and anecdotal report is of in- and recorded its behavior with a video camera terest. Cowles (1920) observed that two Philip- (Panasonic, HC-V480MS, Japan). Time se- pine species of hermit crabs, Dardanus defor- quence analysis of the behavioral pattern was mis (H. Milne Edwards, 1836) (as Pagurus made based on the video recordings. The order deformis) and D. pedunculatus (Herbst, 1804) of the shells provided to the crab is shown in (as P. asper), carried two types of sea anemo- Table 1. The nomenclatures of the shell species nes (species not identified) on their shells: one followed the database of the World Register of large anemone on the top of the shell and an- Marine Species (WORMS), accessed on March other small one on the “underside near the pro- 9, 2018. truding head of the hermit crab” (i.e., at the Observation 1: the hermit crab initially car- shell aperture). Cowles (1920) reported that ried the shell of Neverita didyma hosoyai (Kira, these hermit crabs transferred each sea anemo- 1959), with two individuals of Verrillactis sp. ne to the same portion on the new shell when attached to the columella of the shell aperture. they changed their shells. Since these are dif- To promote a shell change, the outer lip of the ferent species the hermit crab must be able to shell was broken in a vise or with cutting pliers recognize the proper position of each sea to expose the chelipeds of the hermit crab, and anemone species on its shell. However, the a new intact shell of Mancinella siro (Kuroda, transfer of sea anemones onto the shell aper- 1931) was provided. The hermit crab changed ture has not been studied since Cowles’s obser- to the M. siro shell, and its behavior was ob- vations. served. The broken shell of Neverita didyma In the present study, we use both video re- (Röding, 1798) was removed from the aquari- cording and quantitative data to report in detail um. how the hermit crab D. deformis transfers Ver- Observation 2: the M. siro shell that now rillactis sp. to its new shell during a shell housed the crab was then damaged as above, change. and three new and intact gastropod shells, Cas- maria erinaceus (Linnaeus, 1758), Laevistrom-

Crustacean Research 47 Crustacean Research 47 57 AKIHIRO YOSHIKAWA, RYUTARO GOTO, AKIRA ASAKURA

Fig. 2. Observation 5: behavioral sequence of the hermit crab Dardanus deformis transferring the sea anemone Verrillactis sp. from a broken Neverita didyma shell to a new intact N. didyma shell. (a)–(c), the shell change behavior of the crab. (d), the ﬁrst stage of the transfer: the crab began tapping the pedal disc and column of the sea anemone with its walking legs and chelipeds. (e) and (f), ﬁnal stage: the crab used one or both of its chelipeds to pinch and remove Verrillactis sp. from the N. didyma shell (g) and (h), the crab placed Verrillactis sp. near the shell aperture using its walking legs and chelipeds. The black arrows indicate the position of Verrillactis sp. before, during, and after transfer.

Table 1. The order of shell provided to the hermit crab.

Observation 1 Observation 2 Observation 3 Observation 4 Observation 5

Before transfer Neverita didyma hosoyai Mancinella siro Neverita didyma Purpura panama Neverita didyma After transfer Mancinella siro Neverita didyma Purpura panama Neverita didyma Neverita didyma bus turturella (Kuroda, 1931), and N. didyma, After the observation, the vacant shells of M. were provided to the crab. The crab ﬁrst chose siro, C. erinaceus, and L. turturella were re- the L. turturella shell and entered it, but imme- moved from the aquarium. diately exited and entered the N. didyma shell. Observation 3: the N. didyma shell that now

58 Crustacean Research 47 Crustacean Research 47 TRANSFER OF VERRILLACTIS SP. BETWEEN SHELLS BY HERMIT CRAB

housed the crab was broken as described above provided. and an intact Purpura panama (Röding, 1798) The observations were made in daylight shell was provided. The crab changed from the hours on 7 Sept. (observation 1), 20:44 to N. didyma shell to the P. panama shell, and its 24:02 on 8 Sept. (observation 2), 9:05 to 10:55 behavior was recorded. on 9 Sept. (observation 3), 19:14 to 22:10 on 6 Observation 4: the P. panama shell that now Oct. (observation 4), and 20:00 to 22:00 on 10 housed the crab was broken as described in be- Oct. (observation 5), and video recordings fore, and an intact N. didyma shell was provid- were made during observations 2 to 5. ed. Observation 5: the N. didyma shell was broken and another intact N. didyma shell was

Fig. 3. Observation 3, first transfer: behavioral sequence of the hermit crab Dardanus deformis transferring the sea anemone Verrillactis sp. from the accidentally separated columella to the dorsal surface of the same shell. (a), the first stage: the crab began tapping the basal disc and column of the sea anemone with its walking legs and chelipeds. (b) and (c), the intermediate stages: the crab continued tapping the basal disc and column of the sea anemone with its walking legs and chelipeds. (d), final stage: the crab used one or both of its chelipeds to pinch and remove Verrillactis sp. from the broken columella of the Neverita didyma shell. (e), the crab placed Verrillactis sp. on the dorsal surface of the shell with its right walking legs and both chelipeds. (f), Verrillactis sp. on the N. didyma shell inhabited by D. deformis.

Crustacean Research 47 Crustacean Research 47 59 AKIHIRO YOSHIKAWA, RYUTARO GOTO, AKIRA ASAKURA

■ Results of the M. siro shell. Observation 2 (Fig. 1c; Suppl. Video 1): the Observation of behavior crab ﬁrst changed from the M. siro shell to the Observation 1 (Fig. 1b): the hermit crab L. turturella shell, but immediately changed transferred the sea anemone Verrillactis sp. again to the N. didyma shell. The crab did not from the columella (inner lip) of the aperture touch the sea anemone when the crab changed of the N. didyma hosoyai shell to the columella shells from M. siro to L. turturella. After the

Fig. 4. Observation 3, second transfer: behavioral sequence of the hermit crab Dardanus deformis transferring the sea anemone Verrillactis sp. from the dorsal surface of the original Neverita didyma shell to a new Purpura panama shell. (a), the ﬁrst stage: the crab began tapping the pedal disc and column of the sea anemone with its walking legs and chelipeds. (b) and (c), the intermediate stages: the crab continued tapping the basal pedal and column of the sea anemone with its walking legs and chelipeds. (d), ﬁnal stage: the crab used one or both of its chelipeds to pinch and remove Verrillactis sp. from the dorsal surface of the shell. (e), the crab placed Verrillactis sp. on the columella of the P. panama shell using its right walking legs and both chelipeds. (f), Verrillactis sp. on the P. panama shell inhabited by the crab.

60 Crustacean Research 47 Crustacean Research 47 TRANSFER OF VERRILLACTIS SP. BETWEEN SHELLS BY HERMIT CRAB

crab entered the N. didyma shell, it walked to observations). After removing the Verrillactis the empty M. siro shell and detached the sea sp., the hermit crab placed it on the columella anemone from the aperture. The manner of this of the aperture of the new N. didyma shell. Af- transfer behavior was quite similar in all the ter 92 seconds (58–120 seconds in other obser- following observations, so this behavior is de- vations), the crab returned to its normal activi- scribed in detail mainly based on observation 2, ty, such as walking. with some variations in the other observations Observation 3 (Fig. 1d), ﬁrst transfer (Fig. 3, noted in parentheses. The clearest series of Suppl. Video 2): when the shell was broken, time sequence photos for this behavior was ob- the columella of the N. didyma shell with Ver- tained during observation 4, so a set of those rillactis sp. attached was accidentally separated photos is shown in Fig. 2 as representative of from the other portion of the shell. However, all the observations. the hermit crab transferred the sea anemone The detaching behavior of the hermit crab from the separated fragment of the columella consisted of short and quick tapping and pinch- to the dorsal side of its own broken N. didyma ing of the anemone (the crab used its walking shell. This behavior is very similar to that re- legs and chelae). The crab often tapped the ported by Ross (1975) involving Calliactis; the edge of the pedal disk of the anemone and hermit crab used its chelipeds and the second sometimes pinched its tentacles and oral disk and third walking legs to place the Verrillactis using the right cheliped. After 28 seconds of sp. onto the broken shell. tapping (19–78 seconds in other observations), Observation 3, second transfer (Fig. 4, Suppl. the margin of the pedal disk of the anemone Video 3): the hermit crab moved from the bro- started to curl back and upward. The hermit ken N. didyma shell to the intact P. panama crab then pinched the Verrillactis sp. and re- shell and transferred the Verrillactis sp. from moved it from the shell, using one or both of the dorsal surface of the N. didyma shell to the its chelipeds. During the transfer, the Verrillac- columella of the P. panama shell using its che- tis sp. tentacles remained extended. The trans- lipeds and the second and third walking legs. fer itself was done immediately (taking ap- Observations 4 (Fig. 1e; Suppl. Video 4) and proximately 2–6 seconds in all the 5 (Figs. 1f, 5; Suppl. Video 5): the crab trans-

Fig. 5. Dardanus deformis: the comparison of the time taken for each behavior between each trial. The black arrow indicates the time ﬂow after shell change.

Crustacean Research 47 Crustacean Research 47 61 AKIHIRO YOSHIKAWA, RYUTARO GOTO, AKIRA ASAKURA ferred the sea anemone from the aperture of the the aperture of the shell could have great pro- old shell to that of the new shell in a similar tective value for the hermit crabs. If the small manner to that described in the earlier observa- species of sea anemone reported in the anec- tions. dotal observation by Cowles (1920) was Verril- lactis sp., which was transferred across shells Duration of behavioral component by D. deformis and D. pedunculatus, he might The duration of each behavioral component have observed similar behavior as is described is shown in Fig. 5, including the time from ini- in the present study. tiating the detaching action to the start of tap- Another important finding in this study is the ping, the duration of the tapping, the duration high recognition ability of the hermit crabs. of the transfer of the anemone, and the time Other symbiotic sea anemone species are at- from completion of the transfer to the time to tached to the dorsal surface of the gastropod return to normal activity. The time from the shell, the aperture of the shell, or the lateral start of the detaching action to start tapping surface of the major cheliped of hermit crabs was 56–372 seconds (average±SE＝75±13.7 (Antoniadou et al., 2013). However, the pres- seconds, n＝6). The first transfer during the ent study has clearly shown that the hermit third observation was irregular, as the crab crab recognized the site at which the sea anem- transferred the sea anemone from the columella one Verrillactis sp. should be attached onto the that had accidentally been separated from the new shell. Although we observed the transfer main portion of the shell to the dorsal surface of sea anemones by the hermit crab six times, of the same shell. On this occasion, the crab the observations were based on just one speci- spent longer (118 seconds) for this transfer men. Therefore, more observations are needed than for the other regular transfers (average± to clarify whether the present observation is SE＝42.4±37.9 seconds, n＝6). The time of unique to this specimen or is characteristic of transfer of the sea anemone from the old shell the D. deformis species. to the new shell was similar throughout all the The present study indicates a high flexibility observations (average±SE＝3.8±1.5 sec- in the behavior of hermit crabs. When the shell onds, n＝6). The time after the completion of was broken, and resulted in separation of the the transfer to return to normal activity (aver- columella, with the sea anemone attached, the age±SE＝108.2±26.5 seconds, n＝6) was crab first removed the sea anemone from the also similar throughout all the observations. broken piece and placed it on the dorsal surface of its damaged shell. Once the crab had ■ Discussion changed to a new shell, it then transferred the sea anemone from the dorsal surface of the old This is the first quantitative observation of shell to the columella of the new shell. Further the transfer by a hermit crab of a sea anemone study is needed to establish the degree of flexi- attached to the columella of the hermit crab’s bility and plasticity of this type of transfer be- old shell to the same position on its new shell. havior under different conditions. For hermit crabs, the most vulnerable shell This study is also of interest from the view- portion seems to be the aperture of the gastro- point of the phylogeny of sea anemones. Sev- pod shell. The shell aperture is always open, so eral species of sea anemones of the family predators, such as brachyuran crabs, break the Hormathiidae Carlgren, 1932 (e.g., Adamsia outer lip of the shell to eat the hermit crabs palliate (Müller, 1776), Calliactis parasitica (Reese, 1969; Asakura, personal observation). (Couch, 1842), Calliactis tricolor (Le Sueur, Therefore, the placement of a sea anemone on 1817) and Paracalliactis rosea Hand, 1976)

62 Crustacean Research 47 Crustacean Research 47 TRANSFER OF VERRILLACTIS SP. BETWEEN SHELLS BY HERMIT CRAB

that are attached to the dorsal surface of the glou, C., 2013. Symbiosis of sea anemones shells used by hermit crabs are also known to and hermit crabs in temperate seas. In: A. F. react to the tactile stimuli by hermit crabs in a Camisão, C. C. Pedroso (eds.), Symbiosis: similar manner as described in the present Evolution, Biology and Ecological Effects, study (Hand, 1975; Lawn, 1976; McFarlane, NOVA Science, New York, pp. 95–118. 1976; Ross, 1974). However, a review of the Balasch, J., & Mengual, V., 1973. The behavior evolution of sea anemones symbiotic with her- of Dardanus arrosor in association with mit crabs by Gusmaõ and Daly (2010) indi- Calliactis parasitica in artiﬁcial habitat. Ma- cates that the sea anemone species Verrillactis rine and Freshwater Behaviour and Physiol- paguri (Verrill, 1869) (Sagartiidae Gosse, 1858) ogy, 2: 25l–260. Balss, H., 1924. Ü ber Anpassungen und Symbi- and species of the genus Calliactis (Hormathi- ose der Paguriden. Eine zusammenfassende idae) belong to phylogenetically different ü bersicht. Zeitschrift für Morphologie und groups. Moreover, the cooperative behavior Ökologie der Tiere, 1: 752–792. between the symbiotic sea anemone Calliactis Brooks, W. R., 1989. Hermit crabs alter sea conchiola Parry, 1952 (Actiniidae Raﬁnesque, anemone placement patterns for shell bal- 1815) and P. rosea and its host is not observed ance and reduced predation. Journal of Ex- only in hermit crabs but occurs in a spider crab perimental Marine Biology and Ecology, Leptomithrax longipes as well (Hand, 1975). 132: 109–121. However, cooperative behavior has not been Cowles, R. P., 1920. The transplanting of sea reported previously between the sea anemones anemones by hermit crabs. Proceedings of Bunodactis chrysobathys Parry, 1951 and the National Academy of Sciences of the Phellia aucklandica (Carlgren, 1924) (Phelli- United States of America, 6: 40–42. idae Verrill, 1868) and the spider crab L. lon- Conover, M. R., 1979. Effect of gastropod shell gipes. Therefore, communication between sea characteristics and hermit crabs on shell epi- anemones and several decapod species (e.g., fauna. Journal of Experimental Marine Biol- hermit crabs and spider crabs) through tactile ogy and Ecology, 40: 81–94. stimuli may have evolved independently in the Fautin, D. G., Crowther, A. L., & Wallace, C. C., lineages of both sea anemones and decapods. 2008. Sea anemones (Cnidaria: Anthozoa: Actiniaria) of Moreton Bay. In: P. J. F. Da- ■ Acknowledgements vie, J. A. Phillips (eds.), Proceedings of the Thirteenth International Marine Biological We thank Mariko Kawamura, Takashi P. Sa- Workshop, The Marine Fauna and Flora of toh and Kouki Yamamoto (Seto Marine Bio- Moreton Bay, Queensland, Memoirs of the logical Laboratory, Field Science Education Queensland Museum, 54(1): 35–64. and Research Center, Kyoto University) for Gusmaõ, L. C., & Daly, M., 2010. Evolution of sea anemones (Cnidaria: Actiniaria: Hor- their aid to obtain the specimens. We also mathiidae) symbiotic with hermit crabs. Mo- thank Colin McLay (Biological Sciences, Can- lecular Phylogenetics and Evolution, 56: terbury University) and Tsunenori Koga (Fac- 868–877. ulty of Education, Wakayama University) for Hand, 1975. Behaviour of some New Zealand sea reviewing our manuscript and giving us highly anemones and their molluscan and crusta- constructive comments. cean hosts. New Zealand Journal of Marine and Freshwater Research, 9(4): 509–527. ■ Literature Cited Imafuku, M., Yamamoto, T., & Ohta, M., 2000. Predation on symbiont sea anemones by Antoniadou, C., Vafeiadou, A. M., & Chintiro-

Crustacean Research 47 Crustacean Research 47 63 AKIHIRO YOSHIKAWA, RYUTARO GOTO, AKIRA ASAKURA

their host hermit crab Dardanus peduncula- Ross, D. M., 1984. The symbiosis between the tus. Marine and Freshwater Behaviour and 《cloak anemone》 Adamsia carciniopados Physiology, 33: 221–232. (Otto) (Anthozoa-Actinaria) and Pagurus Jonsson, L. G., Lundalv, T., & Johannesson, K., prideauxi Leach (Decapoda-Anomura). Bol- 2001. Symbiotic associations between an- lettino di Zoologia, 51: 413–421. thozoans and crustaceans in a temperate Ross, D. M., & Boletzky, S., 1979. The associa- coastal area. Marine Ecology Progress Se- tion between the pagurid Dardanus arrosor ries, 209: 189–195. and the actinian Calliactis parasitica. Re- Lawn, I. D., 1976. The marginal sphincter of the covery of activity in “inactive” D. arrosor in sea anemone Calliactis parasitica. I. Re- the presence of cephalopods. Marine and sponses of intact animals and preparations. Freshwater Behaviour and Physiology, 6: Journal of Comparative Physiology A, 105: 175–184. 287–300. Stachowitsch, M., 1979. Movement, activity pat- McFarlane, I. D., 1976. Two slow conduction tern, and role of a hermit crab population in systems co-ordinate shell-climbing behav- a sublittoral epifaunal community. Journal iour in the sea anemone Calliactis parasiti- of Experimental Marine Biology and Ecolo- ca. Journal of Experimental Biology, 64: gy, 39: 135–150. 431–445. Stachowitsch, M., 1980. The epibiotic and endo- McLean, R. B., & Mariscal, R. M., 1973. Protec- lithic species associated with the gastropod tion of a hermit crab by its symbiotic sea shells inhabited by the hermit crabs anemone Calliactis parasitica. Experientia, Paguristes oculatus and Pagurus cuanensis. 29: 128–130. Marine Ecology, 1: 73–101. McLean, R., 1983. Gastropod shells: a dynamic Tudge, C. C., 1995. Hermit Crabs of the Great resource that helps shape benthic community Barrier Reef and Coastal Queensland. Back- structure. Journal of Experimental Marine huys, Leiden, The Netherlands, 40 pp. Biology and Ecology, 69: 151–174. Uchida, H., & Soyama, I., 2001. Sea Anemones Reese, E. S. 1969. Behavioral adaptation of inter- in Japanese Waters. TBS, Japan, 157 pp. tidal hermit crabs. American Zoologist, 9: Williams, J. D., & McDermott, J. J., 2004. Her- 343–355. mit crab biocoenoses: A worldwide review Ross, D. M., 1971. Protection of hermit crabs of the diversity and natural history of hermit (Dardanus spp.) from octopus by commen- crab associates. Journal of Experimental sal sea anemones (Calliactis spp.). Nature, Marine Biology and Ecology, 305: 1–128. 230: 401–402. Ross, D. M., 1974. Behavior patterns in associa- Addresses tions and interactions with other animals. In: (AY, RG and AA) Seto Marine Biological L. Muscatine, H. M. Lenhoff (eds.), Coelen- Laboratory, Field Science Education and terate Biology: Reviews and New Perspec- Research Center, Kyoto University, 459 Shira- tives, Academic Press, New York, pp. 281– hama, Nishimuro, Wakayama 649–2211, Japan 312. Ross, D. M., 1975. The behavior of pagurids in symbiotic associations with actinians in Japan. Publications of the Seto Marine Bio- E-mail address of corresponding author logical Laboratory, 22(1–4): 157–170. (AY) [email protected]

64 Crustacean Research 47