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patterns—electric blue in the westernCaribbean, lemon yellow in the Northern
Why Gobies Are Like Hobbits
Caribbean—might be local signals to preda-tors that these gobies are the valet service
As Bilbo Baggins famously warned, trav- genetic breaks between island groups that rather than the entrée. If this is true, then the
live relatively close together. These breaks
wrong color pattern of an “immigrant” goby
coincide with well-established color-pattern
ing where you might be swept off to” (1
differences among goby fish—for example,
the better part of a century, marine biologists
the white and blue forms in the Caribbean
have assumed the roads of ocean currents are
waters around Puerto Rico are genetically
goby populations remain remarkably distinct
distinct populations even though they reside
from island to island, so this explanation can-
within 23 km of each other (see the figure).
not suffice. The other possibility is that the
www.sciencemag.org/cgi/ and larvae and rafting
content/full/299/5603/51 propagules of many
that is, they have a hidden level of drift
far from their homes, on distant shores.
Now, on page 107 of this issue, Taylor and
) help to overturn this notion. They
provide further evidence that at least some
marine species whose larvae have the potential
the larvae of other reef fishes. But this
to disperse over long distances, instead show
and low dispersal. Mantis shrimp in Indonesia
show genetic differences similar in spatial
scale and genetic depth to the gobies studied
contained in larval structures (3
In living color.
) and blue (middle
other, yet remain genetically separate. Even though their
Mexico and the west Atlantic (6
), or between
pelagic larvae could be dispersed over large distances by
the Mediterranean and the east Atlantic (7
ocean currents, the larvae prefer to remain close to home.
These genetic results are paralleled by new
) A cleaner goby (also called a sharknose goby) cleans
information gleaned from the chemical signa-
the parasites from a red hind (Epinephelus guttatus).
ture of fish otoliths (calcareous components of
the inner ear) or mollusk statoliths (calcareous
genetic data, the implications are strong that
The gobies studied by Taylor and Hellberg
very little population exchange has taken place.
have high dispersal potential—their larvae
hard structures of calcium carbonate grow like
remain adrift in ocean currents for about 3
tiny pearls within the animal, depositing a
Taylor and Hellberg study (2
). They show
layer for each day of life—including the days
that there are remarkably strong patterns of
buoys to travel hundreds of kilometers (2
spent as pelagic larvae. As larvae pass through
genetic structure in the mitochondrial genes
Two types of explanations are possible for
different trace-metal environments, the hard
of a small Caribbean reef goby fish (see the
sharp genetic distinctions in the face of such
parts act as a sort of flight recorder that can be
figure). Such patterns demonstrate not only
dispersal potential. First, there might be
read after the larvae settle in their final loca-
that distant islands harbor genetically distinct
strong selection against the wrong genotypes.
tion. The information thus gleaned differs in
populations, but also that there are sharp
These gobies are cleaners—that is, they make
significant ways from that obtained through
their living picking the parasites off larger
genetic analysis. It reflects an individual’s his-
S. R. Palumbi is in the Department of Biological
fish, often the same fish that any rational
tory since birth, including the pelagic pathway
Sciences, Stanford University, Pacific Grove, CA 93950,
goby would consider a dangerous predator.
taken as a larva, and potentially provides much
USA. E-mail: firstname.lastname@example.org R. R. Warner is in
Yet the large fish hold their appetites at bay
more fine-scale spatial data. But the results are
the Department of Ecology, Evolution, and Marine
while the tiny gobies dart about them, picking
Biology, University of California, Santa Barbara, CA
similar to those obtained by genetic analysis.
93106, USA E-mail: email@example.com
their skin clean of parasites. The variable color
For example, populations of fish on tropical
islands are capable of seeding themselves
uncharacteristic in that they are almost all
3. S. E. Swearer et al., Bull. Mar. Sci. 70
, 251 (2002).
despite having larvae that survive for weeks
from island populations (9
). Yet these exam-
4. P. H. Barber, S. R. Palumbi, M. V. Erdmann, M. K. Moosa,
with the potential for long-distance dispersal
ples of fine-scale patterns in genetic or chem-
, 692 (2000).
5. S. Planes, P. Romans, R. Lecomte-Finiger, Coral Reefs
). Whelk populations along the California
ical signatures tell us that the conventional
, 9 (1998).
coast also appear to be colonized by locally
wisdom of marine biology—that the ocean
6. J. C. Avise, Phylogeography (Harvard Univ. Press,
road is a long one for larvae—may prove to be
7. H. Quessada, C. Zapata, G. Alvarez, Mar. Ecol. Progr.
a coarse generalization (10
). It turns out that
, 99 (1995).
using two very different approaches are telling
8. D. Zacherl, thesis, University of California, Santa
us the same thing: that in some times and
either—Bilbo was an exception—and in the
9. C. Mora, P. F. Sale, Trends Ecol. Evol. 17
, 422 (2002).
places, marine larvae are capable of maintain-
end gobies and hobbits like to stay at home.
10. The extent of marine larval dispersal will be one of
ing close links to home despite their proximity
the subjects of a symposium at the upcoming AAAS
to the ocean highways of the sea. Of course,
References and Notes
meeting in Denver, CO: “Opening the Black Box:
1. J. R. R. Tolkien, The Lord of the Rings: The Fellowship
Understanding Ecosystem Dynamics in the Coastal
many other marine species seem to disperse
of the Ring (Houghton Mifflin, Boston, 1994), p. 72.
Ocean” (B. Menge, R. Warner, and J. Lubchenco, co-
broadly, and the examples cataloged here are
2. M. S. Taylor, M. E. Hellberg, Science 299
, 107 (2003).
P E R S P E C T I V E S : C H E M I S T R Y
form. Thus, there are 3 C22H28 tetraman-tanes, 6 isomeric C26H32 pentamantanes,and as many as 17 possible C
Delving into Nature’s Bounty
ferences between their relative thermody-namic stabilities decrease, and the com-
plexity of the potential-energy surface con-
elucidated in 1913 (1
), consists of
forming a tetracyclic cage system. Shortly
thereafter it was recognized that a series of
posed on this diamond lattice. The simplest
of these “diamondoids,” with the common
In a report by Dahl et al.
higher “adamantologs” of adamantane (see
cules. They could neither be isolated from
). Such functionalized
Diamond in miniature.
The structures of adamantane
), diamantane (center
), and triamantane (right
) are seg-
interest in these molecules and their chem-
Schleyer reported that endo
tane (C14H20) (see the figure). This com-
nenorbornane (which can be prepared read-
which is used extensively as an antidyski-
cal antiviral agent to treat Type A influenza
in humans (6
). Polyalkyladamantanes have
). The third member of the dia-
jet fuel blends (8
). There is also
particularly in the area of microelectron-
+12), where n
= 0, 1, 2, 3, …
Dahl et al.
) have isolated and charac-
terized several previously unknown higher
first three members of the series (adaman-
diamondoid hydrocarbons from crude oil.
tane, diamantane, and triamantane) exists
In addition, they have developed improved
The author is in the Department of Chemistry,
as a single isomer, higher members of the
University of North Texas, Denton, TX 76203, USA.
series can exist in more than one isomeric
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