Abstract- The wave-exposed, rocky outcrops of the intertidal zone at Hopkins
Marine Station (Pacific Grove, CA) exhibit large numbers of Lottia gigantea
grazing and homing on what appears to be shared territories. This contradicts
previous studies in which Lottia were found to be solitary and territorial,
aggressively repelling intruders and forming distinct territories of bare rock.
This study observed 58 individually tagged limpets on four sites located on two
vertical rock faces. By taking multiple observations of limpet displacements,
recorded on predrawn maps of each site, limpet home scars and territory
boundaries were identified. Limpet size and home scar height above mean
lower water were also measured. Nineteen individuals were identified as non¬
territorial, 32 as territorial, and 7 as indistinguishable (no movement was
recorded). Non-territorial limpets grazed an area larger than those of their
territorial counterparts (mean = 351 cm2 vs. 199 cm2). The variation suggests
that Lottia territorial behavior may be more complex than previously thought.
Page
Introduction:
The Lottia gigantea is a large, 5-8 cm long limpet that inhabits the rocky
shorelines of Western North America. They are found on outcrops exposed to
the water, preferring vertical walls where wave action is heaviest. Lottia
gigantea are found from the tip of Point Reyes, CA, down to Cerros Island,
Mexico.
In 1970, John Stimson studied the territorial behavior of Lottia gigantea
on the coast of Santa Barbara County, CA. He described the territory of a limpet
as a distinct, round or oval patch of bare rock, bordered by algal growth and
sessile organisms such as mussels. The rock was slightly discolored with an
algal film, and within each area existed one solitary Lottia that grazed on the
film. The limpet showed homing behavior, as described by Fisher (1904), but
also exhibited a defensive territorial behavior in which a resident limpet would
aggressively shove other Lottia and individuals of other species off its territory.
Much work has been done on Lottia since Stimson's original
observations, and most of it has noted that these organisms are indeed
aggressively territorial (Stimson, 1973; Wright, 1982; Wright and Shanks, 1992).
However, Lottia observed on the coast of the Monterey Peninsula, CA, have
exhibited a drastically different behavior. Although many individuals are
observed to maintain territorial patches of rock as described by Stimson, others
were found living together in close proximity on large, bare rock walls without
territorial boundaries. This apparent lack of territories suggests possible
variation in limpet behavior.
Page 3
This study investigates the communal behavior of Lottia gigantea near
Monterey. It attempts to determine whether limpets in the Monterey area are
territorial or are more tolerant of each other and show no distinct territories, and
to determine, if they show variation in behavior, what causes this variation.
Methods and Materials:
Experimental Location and Design
The study was conducted at Point Cabrillo, Hopkins Marine Station,
Pacific Grove, Ca. Two vertical granite rock faces were chosen as test locations
because of the abundant Lottia present, and their ease of access and
observation. Both WNW-orientated faces lie in the mid-to-high intertidal zone,
and are directly exposed to incoming waves. The first rock face contained two
test sites. The two are situated two meters apart, with the smaller Site 2 partially
shielded from waves by a large boulder. Sites 3 and 4 are located adjacent to
each other on the second rock face, divided by a crevice that prevents limpets
from traversing from site to site. This face is located within a shallow cove;
although it is exposed to incoming waves, the cove may reduce hydrodynamic
forces imposed on the face and its inhabitants.
The sites were photographed and measured. Maps of each site were
carefully drawn onto graph paper, using the photographs to mark site
boundaries and all physical features, including rock formations, algal patches,
and mussel beds. Depending on the site, map scales were either 15 or 30 cm
of actual substratum per inch of paper. At 30 cm intervals on the sites, 9 mm
Page 4
circular markers painted fluorescent orange were epoxied onto the rock with Z-
Spar Splashzone Compound marine epoxy. These markers and the cor-
responding maps allowed accurate measurements of limpet location.
Length and width of shell were initially measured for 58 limpets in the
sites. Shell area was calculated by assuming shell shape to be an ellipse, and
using the formula:
A-nab.
a=0.5(length)
b=O.5(width)
Limpet shells were cleaned and tagged with 1x3 cm color-coded markers glued
onto the shells with marine epoxy. The markers were cloth strips painted with
fluorescent paint using four colors in various combinations. The cloth allowed
permanent adhesion of paint and prevented disintegration of the tags by
constant exposure to the waves. Bright colors ensured ease of visibility from a
distance in all light conditions. All edges of the tags had to be buried in the
epoxy to prevent waves from ripping them out. Several limpets were retagged
after waves dislodged the markers before the epoxy hardened. Thus, each
limpet was identified by a color code and recorded by an identification number
assigned to each tag.
Data Collection
Observations were taken from vantage points situated high enough
above the waves to minimize the exposure of the observer and far enough
away to minimize detection of the observer by the limpets. For sites 1 and 2,
this was a tall boulder located approximately 4-5 meters in front of the sites.
Sites 3 and 4 were observed through 10x binoculars from approximately 40
Page 5
meters on the opposite side of the cove when the tide was high, and by wading
out into the cove when the tide was low.
Observation sessions included recording limpet location onto the maps
and looking for any overt behavior (e.g., confrontation between limpets). Time
of day, sea and weather conditions were also noted for each session. A single
map was used to record several sessions, using colored pens to differentiate
between time points. The distribution of observation sessions was as follows:
site 1 was measured 43 times, site 2, 20 times, site 3 and 4, 18 times each.
Data Preparation
After collecting all the data, each location recorded for each limpet in a
given site was labeled on a set of "master" maps constructed on Adobe
Photoshop 3.0 using a Macintosh computer. Connecting the outer-most points
delineated grazing area boundaries for each limpet. Small areas showing
multiple points indicated home scars for each limpet. These locations of high
point density occurred because limpets were often recorded at their home
scars. Because the limpets were plotted with different colors, the master maps
clearly showed grazing territories of each individual.
The area of each grazing range was measured by transferring the
boundary lines onto grid paper, counting grid boxes, and multiplying by the
scaled area of each box. Once home scars were identified, the height of each
could be measured as a distance above mean lower water. Height
measurements were taken with a surveyor's transit and stadia rod, using USGS
Topographic Marker "Mussel Point +1" as the reference point. Each measure¬
Page 6
ment recorded for every limpet was then converted into a distance from that
limpet's home scar by measuring the minimum distance between the point and
home scar.
Tidal heights at the times of observation were calculated using Bryan
Wade's Tide Calculator tide prediction Fortran code program. For each time
point, the tidal heights were interpolated using the heights at the hours before
and after the session. Weather conditions, recorded once per day unless
drastic changes occurred, included sky (sunny, cloudy, foggy), and air (windy or
calm, temperature) conditions.
The data were then compiled in two manners: per limpet and per time
point. For each limpet size, home scar height, territory area, number of times
when displaced from home scar, fraction of observations when displaced from
home scar, and average distance of displacement were listed. At every time
point time, tide height, weather condition, number of limpets displaced from
home scar, fraction of limpets displaced from home scar, and average distance
of displacement were listed.
Next, the data taken per limpet were divided into two separate groups,
territorial and nonterritorial limpets, that were used for comparisons. The
limpets were classified as one or the other depending on two criteria: (1)
whether they exhibited aggressive territorial behavior, and (2) whether their
territories showed overlapping areas. Aggressive limpets with non-overlapping
ranges were deemed territorial.
Page 7
Results:
Fifty-one of 58 limpets were observed displaced from their home scars
more than twice. Two limpets did not move at all during the times observed,
and the remaining five moved once or twice for a distance less than their shell
length. These seven limpets could not be classified as territorial or
nonterritorial; they were, thus, discarded from all data analysis.
Thirty-two limpets appeared to graze in an area in which no other limpet
was found. The remaining 19 limpets were found to share 7-59% of their
grazing area with at least one other individual and are, therefore, nonterritorial.
Limpet numbers 2 and 3, 9 and 14, 7 and 15, 10 and 11, 34 and 41, 53 and 57
shared territory space, limpet 433, 437, and 438 shared, as did limpet numbers
26-29 (see figures 1 and 2).
During the course of the study, limpet 41 and 44, #36 and #49 showed
aggressive encounters in which they met, turned towards each other, pushed
and shoved briefly, then turned away from each other and continued grazing
along their respective territorial boundaries. Limpet #33 had an encounter with
a slightly larger, unmarked limpet that shoved 433 until 433 rotated and
escaped back up into its territory. The unmarked limpet promptly turned around
and returned to its own territory.
Limpet statistics
Initially, the limpets from all four sites were tested as one large sample (n
= 51). Limpet shell size varied from 1423.2 to 3165.1 mm2 with mean = 1638.8
Page 8
mme and standard deviation = 409.8 mm2. The distribution of shell sizes is
shown in figure 3. Territory size showed mean = 255 cm2 and standard
deviation = 230.7 cm2 (range = 14 to 1026 cm2). Home scar height above
MLLW ranged from 24 to 152 cm. Mean height was 78 cm with standard
deviation = 57.6 cm. The limpets were found displaced on the average 35% of
the time, and mean displacement = 13.9 cm.
Regressions indicated that larger limpets had larger territories, and were
found lower on the rock faces. Territory size plotted against shell size (fig. 4),
with both axes log transformed, resulted in a significant positive correlation (R =
0.489, P « 0.001, n = 51). Home scar height regressed against shell size (fig. 5)
also showed a significant relationship (R = 0.373, p « 0.01, n = 51). The log
transformation of both axes in the first regression analysis was performed in
order to minimize the increase in variance in the dependent variable (territory
size) as the independent variable (limpet size) increased.
The average displacement observed at a given time regressed against
the fraction of limpets that moved at that time (fig. 6) indicated a significant
positive slope (R = 0.580, p « 0.001, n = 98). In other words, as more limpets
moved, they traveled farther distances.
The ratio of average displacement to territory size regressed against
fraction of times displaced (fig. 7) showed a significant relationship (R =
0.57274,p « 0.001, n = 51). This suggested that the more often a limpet moved,
less distance it traveled each time.
Page 9
No significant relationships were found between average distance or
fraction of times displaced as a function of tidal height or time.
Comparisons between territorial and non-territorial limpets
For territorial limpets, mean shell size was 1679.9 mm2, with a range from
956.1 to 3165.1 mm2, mean territory size = 199 cm2 (14 - 846 cm2), mean home
scar height = 73 cm (24 - 132 cm). Nonterritorial limpets averaged 1569.7 mm?
(1080.1 - 2048.9 mm2) in shell size, 351 cm2 (77-1023 cm2) in territory size, and
86 cm (47 - 152 cm) in home scar height. T-tests performed between the
territorial and nonterritorial means found no significant differences in either
limpet size or home scar height. However, the test indicated a significant
difference in territory sizes between territorial and nonterritorial limpets. The
nonterritorial limpets had larger grazing ranges.
Log transformed territory sizes were again regressed to limpet size, also
log transformed. Nonterritorial limpets (fig. 8) showed no correlation between
limpet size and grazing range size (R = 0.439, p » 0.05, n = 19), whereas
territorial limpets (fig. 9) showed a significant positive correlation between the
two sizes (R = 0.613, p « 0.001, n = 32). Since the former had a significantly
larger range size than the latter, the groups were retested for the significant
correlation after removing differences in shell size between the groups. A test
for equality of slopes indicated no significant difference between the slopes of
the two regression lines (p = 0.629); analysis of covariance could thus be
performed. Äfter removing shell size as a source of variance between the two
groups, the test still found the mean range size of 351 cm* for nonterritorial
Page 10
limpets to be significantly greater than the 199 cm2 mean for territorial limpets (p
= 0.002).
Regression analysis showed a significant negative correlation between
limpet size and height of home scar for territorial limpets (R = 0,519, p « 0.005)
(fig. 10), but no significant correlation between the two for nonterritorial limpets
(R = 0.110, p » 0.50) (fig. 11). Again, a test for equality of slopes found no
difference between the slopes of the two regressions(p = 0.480), and the
corresponding analysis of covariance found no significant differences in home
scar height between the two groups after removing limpets size as a source of
variation (p = O.194).
Lastly, regression analysis showed a significant inverse power
relationship between the average displacement-range size ratio and the
fraction of times displaced for territorial limpets (R = 0.595, p « 0.001) (fig. 12),
but no similar correlation (R = 0.356, p » 0.10) for nonterritorial limpets (fig. 13).
The slopes of the lines were not significantly different (p = 0.282), and the
following analysis of covariance found no significant difference (p = 0.184)
between the two groups.
Nonterritorial limpets
There was no significant correlation between the measured grazing area
size and the amount of area shared (R = 0.213, p» 0.20, n = 19) (fig. 14). Each
limpet was assigned an adjusted area, defined as a sum of the unshared parts
of its measured grazing area and a fraction of the area shared with other
limpets. The fraction equaled 1/2 if two limpets were sharing the area, 1/3 if
Page 11
three were sharing, etc. The mean of these adjusted area sizes = 307 cm2. The
adjusted area sizes were then plotted against the measured area sizes (fig. 15).
and a highly significant positive relationship was found (R = 0.994, p « 0.001, n
= 19).
A final t-test comparing the means of the adjusted areas of nonterritorial
limpets and the areas of territorial limpets showed no significant difference in
territory size. In other words, all the limpets grazed areas that were
approximately the same size, but those that shared grazing areas with others
required more total range area than the limpets that grazed isolated ranges.
Discussion:
About Limpet Statistics...
Mean grazing range sizes for both territorial or nonterritorial limpets (199
and 351 cm“ respectively) were found to be much smaller than grazing range
sizes measured by other researchers. Stimson calculated territory sizes
averaging 900 cm2 per limpet (Stimson, 1970).
Various factors may contribute to this large discrepancy. First, Lottia
grazing range size changes with algal abundance, shrinking when algae are
abundant and enlarging when scarce (Stimson, 1973). Although no data were
taken on algal abundance in this study, variation in algal density between
Santa Barbara County, where Stimson took his measurements, and here in
Monterey might contribute to the size differences.
Page 12
Next, the large number of limpets in close proximity on the rock faces
might prevent individuals from defending large territories. While Stimson did
not taken population density measurements, preventing any comparison with
this study, this might also contribute to the communal variation in their behavior.
Limpets may lear that defending large territories with others around consumes
a large proportion of energy and time that might not be readily available.
Tolerance of others could have been learned from experience, just as territorial
behavior might have been conditioned from previous experience (Wright and
Shanks, 93).
Regression analysis showed a correlation between limpet size and home
scar height for territorial limpets, but not for nonterritorial limpets. The tolerance
that nonterritorial limpets show of others and their ability to share grazing areas
allow nonterritorial limpets more freedom of movement to locate areas of better
food abundance. As a result, they may not be limited as to where they form a
home scar. On the other hand, existence of home scars indicates that they do
prefer a "home;" thus, they are not completely nomadic.
On territoriality...
The two criteria used to determine territoriality of the limpets appeared to
be sufficient. During the course of observations, the limpets were seen to graze
in distinct areas. For many of the limpets, the boundaries of these areas may be
underestimated. Insufficient data prevented a more accurate presentation of
these areas, especially those under 100 cm2. However, all limpets designated
Page 13
"nonterritorial" were seen in areas shared by other limpets, and all the
"territorial" limpets did show recognition of boundary lines,
For example, limpet +22 and +23, whose home scars were only 20 cm
apart, carefully avoided the other’s territory so strictly that when one came to the
boundary, it would halt, pause, rotate around until it was positioned parallel to
the boundary, then continue grazing along the boundaries. Limpet #1 and 44,
ended a confrontation when each stopped pushing, rotated in opposite
directions, and continued grazing along the border of their adjacent territories in
opposite directions. These limpets were also only 7% different in size (1561.4
vs. 1664.2 mm2). Also, limpet 433, designated "nonterritorial," entered foreign
territory, only to be repelled and briefly chased by the slightly larger territorial
limpet, which left its own ground to chase #33 into the latter's territory. Äfter this
encounter, the unmarked territorial limpet retreated directly back into its territory,
stopping and turning only when it reached its own territory.
This indicates two things. First, all of the limpets seem to recognize
borders and, thus, territories, as seen by the regular grazing of each limpet in a
certain area. This implies a possible chemosensitive (olfactory), visual, or even
tactile behavioral response not yet identified. Since Lottia have been
commonly observed responding defensively to contact with Pisaster tube feet
(Bullock, 1953), it may be possible that they also detect the presence or grazing
areas of other limpets. Next, not all limpets respond to, although they may
detect, the presence of other limpets' territories. One obviously notes the
Page 14
shared grazing areas of nonterritorial limpets, but also some individuals, like
f33, disregard the boundaries of even territorial limpets.
Interestingly, no limpet, territorial or otherwise, was observed intruding
into the area of another's home scar. Some limpets such as numbers 1, 26, 33
and 37 graze past other home scars, but never have they been seen grazing
over a scar. Distance between home scars has no relationship to territoriality of
neighbor limpets; some territorial limpets home at locations just 10 cm apart
while others are 40 cm apart, and nonterritorial limpets and combinations of
both show similar numbers in home scar distances.
Previous papers (Stimson 1970, 1973) describe limpet territories as
circular or oval areas. Although this may be true for solitary, territorial limpets,
this did not seem to be the case for communal limpets. Again, insufficient data
may be the culprit, but the tested individuals often showed long, narrow
territories that border on large rock formations or algal patches. Individuals
grazing on such territories include limpet numbers 15, 21, 29, 32, 33, and 53.
Rock formations are difficult to bulldoze, so limpets have to accommodate to
such obstructions One such formation seems to prevent limpet #32 and #33
from grazing on each other's area. On the other hand, limpets are known to
bulldoze algal clumps when forming and maintaining territories, but the limpets
in this study were observed grazing around patched of Endocladia in their
territories.
Some limpets homed at one location, but then traverse great distances to
graze. Limpet 410, 411, 418, show this pattern.
Page 15
„.And the nonterritorial limpets
The amount of shared grazing area may depend on limpet density, local
resource abundance, and location. At site 2, four of five limpets shared
substantial proportions of their territories (30%-59%). These limpets also
homed at close proximity to each other; limpet +27 and +28 homed the closest
at 6 cm apart, limpet +25 was 15 cm from +27, and +29 was 30 cm from +28 (fig.
Apart from site 2, in which close proximity of individuals and large
overlap among ranges showed otherwise, no two limpets were seen in shared
areas simultaneously. When one limpet was within the shared area, the other
was observed grazing elsewhere. This may be due to pure coincidence, distinct
grazing patterns that placed limpets apart at a given time, or a sense of
temporal territoriality. Although verification of this speculation will require a
completely new study, perhaps the limpets can sense the presence of others
such that they will actively avoid the other when grazing in a shared area. This
again suggests possible chemoreceptive behaviors in Lottia.
Conclusion:
The results of this study indicated that variation does exist in the territorial
behavior of Lottia gigantea. Nineteen of 51 limpets were designated as
nonterritorial limpets because they grazed on shared territories, and exhibited
no aggressive behavior towards others. The other 32 limpets were considered
territorial since they appeared to maintain and defend territorial spaces. All
Page 16
limpets, however, lived communally and in close proximity on the rock faces,
Resource abundance and space limitations may play a role in determining the
behavior of the limpets, as might possible chemoreceptive mechanisms or a
sense of temporal territoriality. Since the study did not include such
measurements, this is not conclusive. As indicated, the traditional view of the
aggressive Lottia and its territory is not entirely correct; the territorial behavior in
the limpets may be more complicated than previously deemed.
Acknowledgments:
Much gratitude to Mark Denny for his guidance, input, and advise in
collecting data and writing this paper. Also, thanks to Jim Watanabe for his help
with the statistical analysis, John Lee for his help with the camera set up, and to
Bryan Sun and Steve Randle for their help in collecting data.
Literature Cited:
Bullock, T. (1953). Predator recognition and escape responses of some
intertidal gastropods in the presence of starfish. Behavior 5: 130-140.
Fisher, W. (1904). Anatomy of Lottia gigantea. Zool. Jahrb. Anat. 20(1): 1-66.
Stimson, J. (1970). Territorial behavior of the owl limpet Lottia gigantea.
Ecology 51: 113-118.
Stimson, J. (1973). The role of the territory in the ecology of the intertidal limpet
Lottia gigantea. Ecology 54: 1020-1030.
Wright, G. W. and A. L. Shanks (1993). Previous experience determines
territorial behavior in an archaeogastropod limpet. Exp. Mar. Biol. Ecol.
166: 217-229.
je 19
Figure Legend:
Fig. 1) The maps of sites 1 and 2, showing all locations observed of all limpets.
Each limpet is color coded, and the lines delineate boundaries of grazing
ranges. The areas within each range that show a high density of points
indicates home scars.
Fig. 2) The maps of sites 3 and 4, showing all locations observed of all limpets.
Each limpet is color coded, and the lines delineate boundaries of
grazing ranges. The areas within each range that show a high density of
points indicates home scars.
Fig. 3) Histogram distribution of limpet shell sizes.
mean = 1638.8 mm2, standard deviation = 409.8 mm2
range = 956.1 - 3165.8 mm2
n =51
Fig. 4) Territory size (log transformed) regressed against limpet size (log
transformed).
R =0.489, p « 0.001, n = 51
Territory size shows a significant positive correlation with limpet
size. Territory size increases as limpets get larger.
Fig. 5) Limpet size regressed against home scar height.
R = 0.373, p « 0.01, n =51
Limpet size is negatively correlated with height of home scar. Larger
limpets form home scars lower on the rock, closed to the water.
Fig. 6) Average displacement of limpets recorded at any given observation
session regressed against the percentage of the limpets that moved at
that session.
R = 0.580, p « 0.001, n = 98
There was a positive correlation between average displacement of
limpets and the fraction of limpets displaced at a given observation
session. Under favorable environmental conditions, when more limpets
move, they move greater distances.
Fig. 7) The ratio of average displacement to territory size regressed against the
fraction of times a limpet was found displaced.
R =0.573, p « 0.001, n = 51
Since the average displacement for a limpet depended on territory
size, the ratio of the two provided a normalized measure that could be
compared to the frequency of limpet displacements. A significant
negative relationship was found. A limpet that moved more frequently
covered less distance in its territory each time compared to a limpet that
moved infrequently, but traveled greater distances when it did move.
Page 20
Fig. 8) Territory size (log transformed) regressed against shell size (log
transformed) of nonterritorial limpets.
R =0.439, p» 0.05, n = 19
In nonterritorial limpets, there was no significant correlation between
territory size and shell size. Size of territory did not depend on size of
limpet.
Fig. 9) Territory size (log transformed) regressed against shell size (log
transformed) of nonterritorial limpets.
R =0.613, p « 0.001, n = 32
In territorial limpets, there was a significant positive correlation between
territory size and shell size. Territory size did depend, to a great degree,
on size of the limpet.
Fig. 10) Territorial limpet size regressed against home scar height.
R =0.516, p + 0.005, n =32
In territorial limpets, limpet size was negatively correlated with home scar
height. Larger limpets were found lower on the rock, closer to the water.
Fig. 11) Nonterritorial limpet size regressed against home scar height.
R=0.110, p» 0.50, n = 19
In nonterritorial limpets, limpet size did not determine the height of its
home scar. These limpets were found homing at all heights.
Fig 12) The ratio of average displacement to territory size regressed against the
fraction of times a territorial limpet was found displaced.
R =0.595, p + 0.001, n =32
Since the average displacement for a limpet depended on territory size,
the ratio of the two provided a normalized measure that could be
compared to the frequency of limpet displacements. A significant
negative relationship was found. A territorial limpet that moved more
frequently covered less distance in its territory each time compared to a
limpet that moved infrequently, but traveled greater distances when it did
move.
Fig. 13) The ratio of average displacement to territory size regressed against
the fraction of times a nonterritorial limpet was found displaced.
R = 0.356, p» 0.10, n = 19
No significant correlation was found between the average displacement
to territory size ratio and fraction of times a nonterritorial limpets was
displaced. The trend indicates that these limpets behave similarly to
territorial limpets, but insufficient data on limpets that moyed less than
10% of times prevented a statistically conclusive correlation.
Page 21
Fig. 14) The fraction of shared territory regressed against the measured territory
size of nonterritorial limpets.
R=0.213, p» 0.20, n = 19
No significant correlation was found. The fraction of territory shared
between limpets did not depend on the observed measured size of the
territories.
Fig. 15) The adjusted territory size regressed against the measured territory
size.
R =0.994, p + 0.001, n = 19
There was a significant positive correlation between adjusted territory
and measured territory sizes. Regardless of the proportion of territory
that was shared, the adjusted territory size was directly proportional to
measured territory size.
Page
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Page 23
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Page 24
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Figure 3
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Page 25
Figure 4
Territory Size in Relation to Limpet Size (Log Trans.)

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Page 26
Limpet Size in Relation to Home Scar Hgt.
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Page 27
Average Displacement Recorded at any Given Time Point
in Relation to the Percentage of Limpets that Moved
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Page 28
Figure 7
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Page 29
Figure 8
Territory Size in Relation to Nonterritorial-Limpet
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Page 30
Figure 9
Territory Size in Relation to Territorial-Limpet
Size (Log Transformed)




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2.6
E
GO
Q OO
2.2




C



1.8


C
.

1.4

—
—
E
2.9 3 3.1
3.2 3.3 3.4 3.5 3.6
Log Shell Size (mm2)
Page 31
Territorial-Limpet Size in Relation to
Home Scar Hgt.
—
3500



—
0
sssces
3000
O
2500

—
2000
O
88
0
000
1500
O
—

(
1000
50E
20 40 60 80 100 120 140 160
Home Scar Hgt. (cm)
Figure 10
Page 32
Nonterritorial-Limpet Size in Relation to
Home Scar Height.
3500



3000

.
2500



2000
C



5 1500

O
.
0
1000
50 ETIET
20 40 60
80
100 120 140 160
Home Scar Height. (cm)
Figure 11
Page 33
Ave. Displacement/Grazing Range Size in Relation to
% Times Displaced of Territorial Limpets
—
0.7

—
0.6

Leseeeeeeeeessssssssse
0.5


E 0.4
O
--¬
0.3


3 0.2
8
S0


0.1
3B0o
0


0.4
0.6
0.8
0.2
% Times Displaced
Figure 12
Page 34
Ave. Displacement/Grazing Range Size in Relation to
% Times Displaced of Nonterritorial Limpets
0.7
——

—-------

0.6

8 0.5

-e-
0.4

c

0.3
—

essseeseesssssesesee
0.2

.
0.1

0 0
P
0.4
0.6
0.8
0.2
% Times Displaced
Figure 13
Page 35
Nonterritorial Limpet Grazing Area Size
and Corresponding Percentage of Shared Area
—
esssesesssessseesessee
0.8
—..
Seesseeeeeesesessssese
0.6
—.
Messseeseeeeeseeessese
0.4
.
O
0.2
00
E
200 400 600
0
800
1000 1200
Grazing Area Size
Figure 14
Page 36
Measured Grazing Area Size Compared to
Adjusted Grazing Area Size
1000

—


...
leeeeeessessssssesssesee
800

600
—

400
80
-n-----------
200
88

200 400 600 800 1000 1200
0
Actual Grazing Area Size (cm?)
Figure 15
Page 37