(1) Phragmatopoma californica is a suspension feeding polychaete of the family Sabellariidae. It is a common species in California, forming massive reefs (Smith and Carlton, 1975). Members of this family live in tubes that they construct from sand and shell fragments. The anterior end of these tubes increases in diameter to give a flared terminus. Clusters of these flares result in the colonies having a beehive appearance. Thus, these worms are often referred to as the honeycomb worms. Except for studies by Roy (1974) which dealt primarily with activities of P. californica within its tube, the observations of this paper are new with respect to forma- tion of the flared terminus of the tubes by this species. Kirtiey (1968) described the building of massive reefs on the Florida coast by Phragmatopoma lapidosa. Wilson (1968, 1969) described the larval settlement behavior and resulting colonial stucture in the honeycomb worm, Sabellaria alveolata. Vovelle (1965) investigated forma- tion of tubes and the nature of colonies in S. alveolata Most specimens of Phragmatopoma californica exhibit degrees of te ube i 130 flages (2) flares that occupy approximately 180 degrees of the tube diameter. For a number of reasons, flares also commonly deviate from 180 degrees. The flares usually project farthest in the middle and taper towards the sides. Initial inspection of many colonies makes it appear that organization of the flare is random. Further investigation of flares within colonies reveals them to be oriented often in the same direction. Preliminary field observation and experimentation demonstrated that when the flares were scraped off they were usually rebuilt within twelve hours and in the same direction as previous ones. Worms could rebuild their flares in one or more differing directions placed in new locations. Other early when colonies were field observations seemed to show that colonies tended to orient away from strong flows of current. However, colonies maintained in aquaria after their flares had been removed were seen to rebuild towards a relatively weak current. The purpose of this paper is to demonstrate that certain environmental factors influence the construction and direction of flares by Phragmatopoma californica. It will (3) also try to determine the role that predominating currents might play in flare formation. Materials and Methods: Experiments were carried out on colonies of Phragmatopoma californica obtained from the rocky intertidal between Point Cabrillo and Point Allones, Pacific Grove, California. Field studies were conducted in the area from which colonies were collected. This area runs southwest to northeast into the ocean, and has P. californica colonies extending approximately from the +3.3 foot to the -3.0 foot tide level. It is surrounded by sand on either side. The area is semiexposed and subject to a fair amount of wave action. The P. californica colonies are mainly located on rocks. Laboratory experiments took place at Hopkins Marine Station. They consisted of simulated field situations with directed current in both indoor aquaria and an outdoor pool equipped with a submersible pump. When flare removal was required this was done simply (4) by scraping the face of the colony with a straight edged instrument. Experimental and Results: Some Environmental Effects on Flare Construction A large colony, about 1 m by 1.5 m, was located for experimentation. The colony appeared as an orderly array of individual tubes, extending almost vertically from the upper surface of a rock. Flares were generally oriented facing southwest (Figure 1A). Portions of the colony were separated and their flares scraped off. These segments of no less than 15 worms were placed in a triangular, wire cage having its bottom at the -0.1 foot tide level (Fig. 10). They were positioned so that the side that had been nearest land was now adjacent to a cage wall and with the same flare orientation (Fig. 1A). The subcolonies were kept in place by being wrapped in a wire screen which was fastened to the cage. Worms were left in the cage for 24 to 48 hours, time enough for the building of new flares. Following this time (5) interval the subcolonies were then removed and the new flare angle was measured with a protractor (Fig.riB). The entire procedure was then repeated, replacing the worms in a new cage location. A t-test for two independent samples revealed P. californica to have changed flare direction to a.07 level of significance in three out of four field tests. All cases of significant change took place when a colony was moved from the front of the cage, facing the sea, to the back, facing land, or vice versa. ruction in Different Degrees of Current Flare Cons A regularly organized colony of Phragmatopoma californ- ica was obtained from the intertidal and brought into the laboratory. The colony was divided into six segments of no less than ten worms each. These pieces were placed at no more than 33 cm. interval with wooden blocks positioned between them. Any open spaces were filled with modeling clay so as to create a smooth, solid surface on which the colonies were facing. The pieces were positioned so that they all pointed in the same direction (Fig. 24). The (6) entire apparatus was placed in a large circulating sea- water tank with a pump positioned so that a decreasing current ran down its face. Sand, obtained from Aggassiz Beach, was dispersed at the pump outlet so that it would be carried in front of the worms. The current was measured in meters/second by timing the passage of methylene blue dyed seawater through a one meter tube, having an inner diameter of 3.3 centimeters, with its opening at the front of each surface in question. The worms were left for 40 hours then removed. Flare angles were recorded (Fig. 2B). The flares were then re- moved and the entire apparatus replaced, but with a 180 degree turn so that the colonies were now upside down relative to their previous position (Fig. 2B). When flares were again measured the same polar axis was used as in the first trial. The reason for this was that the major con- cern was whether the flare was oriented towards or against the oncoming current. For example, in both cases a flare measuring greater than O degrees and less than 90 degrees was directed towards the current. In Trial I it would be located on the upper left hand side of the tube with the current coming from the right, while in Trial II it would be located on the lower right hand side with current coming from the left. There appeared to be no correlation between the flare angle and current velocity (Table 2). A t-test for two independent samples showed only one subcolony to have changed their flare angles significantly from Trial I to Trial II (Table 3). Discussion: Studies conducted in the field and in the laboratory show that in some instances colonies of Phragmatopoma californica will change the direction of their flares. A significant change among field cases took place when sub- colonies initially facing the ocean were turned to face land and vice versa. In all of these examples flares were directed farther away from a 90 degree angle when colonies were facing the sea. It may be that the incoming wave action exerted a maximum, detrimental effect on the worms when flares were at this angle. Bendimg the flares to the (8) left or right may have lessened the force of waves and thus provided some protection for the worms. Subcolonies not changing flare direction were those that were moved from facing land to facing the side of the cage, or were in the circulating pool. These results may indicate that colonies of P. californica tend not to change the position of their flares and will only do so when absolutely necessary. The worms maintaining their origin- al flare orientation may not have had an environmental shift stressful enough to require any change. Preliminary observations indicated that worms placed in a fast current may try to protect themselves by using their flares as a shield, while those in a slower current which direct their flare towards the flow may be doing so to increase their chances of catching food particles. Lab- oratory attempts to correlate the strength of current with the direction of the flare proved inconclusive. It may have been that the range of currents tested was not sufficient to warrant change of flare position. It would be interest- ing to see if one placed a colony in two extreme current (9) velocities and cause a change in flare orientation from facing a current to opposing the current. The two colonies in the pool which built no flares during the first trial may not have done so because the water movement was too forceful to allow them to extend their tentacles and catch the sand particles necessary for flare construction. It may also have been that the sand was not suspended for a long enough time in front of the worms to allow it to be seized. Additional field observations bring to attention the possible function of the flare in retaining water. P. californica was seen only to extend its tentacles when in an aqueous environment. When colonies which had half of their flares shaved off were observed while the tide was coming in, it was noted that the worms with flares, unlike those lacking them, were able to keep their tentacles ex- tended for a longer period of time after waves had washed over them. The reason for this appeared to be that the flares were able to hold water for short periods of time after the major run off had occurred. (10) Summary: 1. Colonies of Phragmatopoma californica rebuilt their flares in the same direction if unmoved. 2. Colonies of P. californica were observed to occasionally change the orientation of their flares in the field. 3. It appeared that currents may dictate flare con- struction, strong currents causing flares to oppose them and weak currents causing flares to face them. 4. A speculated use for the flare may be in water retention, allowing tentacles to be used. 4 -— 7 —.— Land - Lateral View Phragmatäpoma californica Colony 8 ——— — . . —.— — —- —- —---- - -— — — — LAND Back Left Front OCEAN 94 80 (11 — gure 2 0 —— Cage Wall Top View —.— — + --- - - — —7/. . Cross Section Top View — . + —---- â - — — —-- — -—1.— — — --- ——.— .. -.. —. —------— Right —— — — O0 6 . (12) igure2 —— — - OC C —— — oc 7BOwoed OO 4 Block O ooe S —— oo0 --- O. — -. —1 —- Cross Sation Top View — Phragmatapoma californica Colony +—— — Current ) â - . .- — Trial 4 - -- — —— 4 A B —: â â -- - —.— Current ——— B A 00 Trial2 —5 6 De —— - AB A Legend Right ZL Side of Subcolon —— —--- — = Front (13) Legend: Diagram 1A- Positioning of P. californica colonies in cage. 1B- Measuring flare angles. 10- Positioning of the cage between two rails, front facing ocean. Diagram 2A- Placement of colonies in pool apparatus. 2B- Positioning of apparatus in pool and measurement of angle after trials. 8. — 5 - o o a 55 a0 8 8 50 9 2 — O 1 c . (14 Table II Mean and Standard Deviation of Flare Angles (degrees) No flares built Not flares built 100127.05 48.75t25.51 89.09119.6 102.5115.81 83.93112.12 66.32112.6 98.46114.63 124.29-37.35 (15) Current Velocity (m/sec) .85 .55 .11 .32 .31 .3 .3 .27 .23 .2 +- — 0 + + 58 o 0 Bd C 5 2 O H katvvo (16) (17) Literature Cited: Kirtley, D.W. 1968. The Reef Builders. Nat. Hist., 77:40-45. Roy, P.A. 1974. Tube Dwelling Behavior in the Marine Annelid Phragmatopoma californica (Fewkes) (Polychaeta: Sabellariidae). Bull. South. Calif. Acad. Sci., 73:117-125. Smith, R., Carelton, J. 1975. Lights Manul, Univ. Calif. Press, Berkeley, 716 pp. Vovelle, J. 1965. Le tube de Sabellaria alveolata (L.) et son cement. Etude ecologique, experimrntale, histologique, et histochimique. Arch. 2001. Exper. Gen., 106:1-187. Wilson, D.P. 1968. The settlement behavior of the larvae of Sabellaria alveolata (L.). J. Mar. Biol. Assoc. U.K., 18:367-435. 1969. The Honeycomb Worm. Sea Frontiers 15:322-329.