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EndEmic insEcts
of Rapa nui
searching for vestiges of
ancient ecosystems
by jut Wynne
R e t u R n o f f l a g n º 1 3 9
Since it S firS t f oray in to the fie ld in 1949 ,
fl ag 139 haS be en c arr ied acro SS glacierS in
al aSk a, t hrough cen tra l china on an anc eStra l
ga llifor meS e xpedit ion, and into the jungleS
of yucatá n, m exico, on a jaguar St udy. ove r
the paSt d ecade, thiS flag h aS acc omp anied
jut Wynne on 11 reS earch t ripS—to th e atac ama
and moj ave deS ertS for a n aSa cave detect ion
proje ct a nd to the n orth rim o f the grand
ca nyon, Sout hern china , and South ern S pain for
vario uS cave biolo gy StudieS.
I vividly remember my first encounter with
Rapa Nui (Easter Island). I was ten. My
grandmother bought me a box of National
Geographic magazines at a garage sale.
Unbeknownst to me, her gesture of thought-
fulness would portend many expeditions to
come. For tucked within that musty box was
a tattered issue from 1962 with a story on
Rapa Nui. For days, I peered at the pictures.
I marveled at the mysterious moai, those
towering monolithic statues. I became
transfixed by the exotic landscapes. One
day, I vowed to visit that isolated Polynesian
outpost. Little did I know that decades later,
colleagues and I would make numerous
a fel loW of the explor erS club Since 200 6, jut W ynne iS an aSSiStant reSearch profeSSor With the department
of biological ScienceS, merriam-poWell center for environmental reSearch, norther n ariZona univerSit y.
he StudieS the animalS uSing cave S a nd other hard-to -reach placeS around the Wor ld. thiS project WaS
Sup ported by the fulbright viSiting Schola rS program, cona f-parQue nacional r apa nui, yale cordage , the
explorerS club, the nati ona l Speleol ogica l Socie ty, ripcord travel protection, and onSet comp uter corp.
to foll oW hiS exploitS, viS it or folloW him on t Witter/inStag ram @ju tW ynne.
team memberS peer into the crater of rano kau.
photograph by nicholaS glover. previouS Spread: vieW of
the north Shore of rapa nui from a cave entrance, Sector
unai. photograph by jut Wynne.
ra no k au
ra no ar oi
ra no r ara ku
cav eS
cli ffS
be ache S
cr ater S
roc ky c oaSt
fe rn ga rden
Sur face gri d
th E Ex ploR ERs jo uR na l
contributions to the island’s natural history
and cave ecology.
In 2008, I was bound for the Atacama
Desert of northern Chile to lead the first trip
of a three-year study supported by NASA’s
Exobiology program. Our objectives were
to model the thermal properties of caves
and develop procedures for detecting Earth
caves using thermal remote sensing. We
believed this study would lay the ground-
work for systematically finding and ultimately
targeting Martian caves for robotic explora-
tion—as subterranean Mars represents the
best place to find evidence of life, provided
life ever evolved there. As I prepared for
this expedition, I realized I would be within
striking distance of Te Pito o Te Henua (the
navel of the world), as it is known to the
Rapa Nui and throughout Polynesia.
Governed by Chile, the island is
3,600 kilometers off the South American
coast, five and a half hours from Santiago
by plane. I knew I had to go. So I did my
homework and fleshed out a study design
to conduct a baseline effort of cave eco-
systems. Within weeks I was preparing for
back-to-back expeditions—first to the driest
desert on Earth, and then to Rapa Nui.
Following human colonization (between
the ninth and thirteenth centuries ce), the
island underwent a process known to ecol-
ogists as a “catastrophic ecological shift.” A
number of environmental factors, including
geographic isolation, small size, shallow
topographic relief, low latitude relative to the
equator, and aridity (when compared with
other South Pacific islands) predisposed
the island to dramatic human-induced envi-
ronmental change. Most notably, the arrival
of humans was inauspiciously timed with
an extended drought. The ancient island
ecosystems were largely fire-intolerant. So
as humans ultimately introduced fire into the
system, this likely exacerbated the shift.
The ancient Polynesians were one ingre-
dient in a potent cocktail that transformed
Rapa Nui. According to some estimates,
the human population swelled to more than
10,000 inhabitants. This is an impressive
figure for an ancient civilization perched
upon 164 square kilometers of volcanic
rock in the middle of the South Pacific. A
large number of people tapping finite natu-
ral resources in highly sensitive ecosystems
came at a cost.
Contemporary Rapa Nui is quite differ-
ent from what the Polynesians initially ex-
perienced. By the time the first Europeans
arrived in 1722, the island’s once-lush
palm-dominated scrub forest had largely
shifted to grasslands. Further environ-
mental degradation took place during the
mid-nineteenth century, when most of the
island was converted into a century-long
sheep-grazing operation.
Rapa Nui is now one of the most ecologi-
cally degraded islands in the South Pacific.
Prehistoric, historic, and modern land use
practices have all contributed to the loss of
most native plant and animal species.
Of the remaining 43 endemic plant spe-
cies, 35 have been listed on a sensitivity
gradient from rare to critically endangered.
While 17 species of pelagic birds form
rookeries on the island and surrounding
motus (tiny islets), all ground-dwelling ver-
tebrates have long since perished.
Today, the island may be viewed as a
natural laboratory to investigate questions
related to extensive biological transforma-
tions in isolated ecosystems, ecosystem
responses to invasive species colonization
events, and landscape-scale environmental
change, as well as how alien insect commu-
nities assemble to form a key element of an
ecosystem. Rapa Nui’s ecological shift may
rapa nui naturaliSt SebaStián yancovic pakarati
SearcheS for inSectS in a cave in Sector roiho.
photograph by nicholaS glover.
also provide a window into the ecological
adaptations that isolated endemic species
undergo (or don’t) given numerous environ-
mental stressors.
When I began studying insects on Rapa
Nui nearly a decade ago, 21 endemic spe-
cies were known from the literature. As most
had not been observed since their initial
discovery, it is likely these endemic insects
are now extinct. However, I posited that if
vestiges of Rapa Nui’s ancient ecosystems
persisted, we would find them in the form of
insects within the somewhat buffered envi-
ronments of caves. As I was strategizing my
first expedition, I was optimistic we would
find cave-adapted animals (or troglobites).
Confirmation of these evolutionary mar-
vels would be proof-positive of endemic
relict species of ancient Rapa Nui. Telltale
traits of cave-adapted insects are the lack
of pigmentation, elongated legs and/or
antenna, highly reduced eyes or no eyes at
all, and they’re often quite hairy. Shedding
surface characters in favor of this subterra-
nean tool kit can take a while, evolutionarily
speaking. If we confirmed the presence of
troglobites, this discovery would be indica-
tive of them adapting to subterranean envi-
ronments. At the same time, it would negate
any notion of a recent colonization event,
human-assisted or otherwise. As a result,
these animals would be of tremendous
importance for future conservation efforts.
My first foray to Rapa Nui in 2008 was
a two-cave pilot study. This effort laid the
groundwork for three follow-on expeditions
between 2008 and 2011. We focused
on ten caves within the Roiho lava beds,
an area with the highest concentration of
caves on the island. Although we did not
confirm the presence of insects evolution-
arily constrained to these deep recesses,
we made several fascinating discoveries.
We unearthed eight island endemic and
two Polynesian endemic species. Eight of
the ten endemics were new to science!
These animals ranged from tiny eye-
straining springtails (Collembola) and book
lice (Psocoptera) to the larger bodied roly-
polys (terrestrial isopods). We found these
endemic species primarily in the fern-moss
gardens within cave entrances and beneath
cave skylights. However, four species were
detected lurking in the deepest reaches of
two caves. Because these animals appear
restricted to cave entrances, yet range into
the most environmentally stable reaches of
caves, we postulated their ostensibly cave-
wide distributions may represent the earli-
est stage of an evolutionary shift toward
cave adaptation.
For our two newfound Polynesian en-
demics, we dubbed these animals “canoe
bugs.” The ancient Polynesians dispersed
numerous plant species as they masterfully
navigated the South Pacific, island-hopping
and colonizing eastward in massive dou-
ble-hulled voyaging canoes. These “canoe
plants” provided food, medicine, and other
uses such as materials for nets, rope, sails,
and clothing. Once these stalwart seafar-
ers made landfall, they would grow these
cultivars on the newly colonized island. Our
“canoe bugs” were presumed stowaways
within the soil of these plants.
The discovery of ten presumed cave-
restricted endemic insects left us with
more questions than answers. More than
half of our new species were found in
low numbers (in most cases, one to two
individuals), leading us to suspect they are
imperiled and at risk of extinction.
Are these species simply evolutionary
dead ends living on borrowed time? If not,
how have these species persisted despite
hundreds of years of environmental change,
the author about to deScend a 300-meter cliff in Sector
poike, located in the SoutheaSternmoSt extent of iSland.
photograph by dreW briStoW.
th E Ex ploR ERs jo uR na l
as well as presumed competition with
and predation by alien species? Are they
restricted to caves in only one area, or do
they occur in other caves across the island?
Could these species exist in other similarly
protected surface habitats? Do additional
endemic species persist in other protected
surface habitats as well?
This agglomeration of questions cou-
pled with the relatively limited scope of prior
expeditions compelled me to undertake an
island-wide search for endemic insects.
My goals were to search for our ten new
endemic species elsewhere, uncover ad-
ditional new endemic species, and identify
and characterize the habitats most essential
to the persistence of endemic insect fauna.
Much as NASA prescribes to a “follow the
water” approach in its search for evidence
of life on Mars, I proposed we “follow the en-
demic plants” on Rapa Nui. I hypothesized
where there are endemic plants, there will
be endemic insects. This research would
zero in on caves, cliffs, coasts, and crater
lakes. These areas are the only known lo-
calities where patches of native vegetation
remain as they may be protected from hu-
man activities and livestock grazing. I further
hypothesized that steep cliff faces may be
inaccessible to rats and alien plant species,
and may represent the most important relict
habitat on the island.
Proyecto de Conservación de Insectos
Endémicos launched in June of 2016.
With four teams of Rapa Nui park rang-
ers and community members (notably
Francisco Ika, Lazáro Pakarati, and
Sebastián Yancovic Pakarati), Explorers
Club members, citizen scientists, and
undergraduate students, we combed the
island in search of endemic insects. Over
a period of three and a half months, we
sampled 49 sites, including 20 caves, ten
cliff faces, the three crater lakes (Rano
Aroi, Rano Kau, and Rano Raraku), eight
rocky coastlines, the two main beaches
(Anakena and Ovahe), two inland surface
areas containing patches of native ferns,
and four surface control sites. We col-
lected insects in each locale using an
array of sampling techniques.
The teams endured high winds and in-
tense rainstorms while dangling from ropes
off cliff faces, hiked in 30-knot winds to ac-
cess caves, and even witnessed a roadside
wildfire, which was quickly extinguished by
an intense rainstorm. We also sampled the
most formidable crater lake on the island,
Rano Kau. In several areas skirting the cra-
ter lake, the totora reeds were impenetrably
thick. The person blazing the trail would
dive onto the reeds, flatten them slightly,
climb atop the slightly flattened reeds, and
repeat. To stave off complete exhaustion or
running out of potable water, team mem-
bers took turns leading the charge, rotating
every 15 minutes.
Among our most important study sites,
Rano Kau supports the highest diversity
of plant species on the island. At least 12
endemic or indigenous plants and at least
five “canoe plant” species have been con-
firmed. Interior crater walls receive varying
degrees of sunlight given aspect, time of
day and season, and the interior is charac-
terized by large boulder fields and vertical
cliff faces. In aggregate, this produces high
habitat heterogeneity, which translates to
numerous ecological niches for endemic
insects to occupy.
For our 20 study caves, we sampled
the deepest reaches for troglobitic insects.
We also collected hourly temperature and
relative humidity data at each cave using
HOBO Pro data loggers and mapped 15
of the study caves for which maps did not
exist. Meteorological and structural data
will be used to characterize cave habitats.
My unofficial goal was to double the
number of endemic insect species known
to Rapa Nui. Because we started with a
low number of presumed extant endemic
an undetermined SpecieS of the genuS
(family halophiloSciidae, order iSopoda). thiS
morphoSpecieS repreSentS a neW iSland record
for thiS family and genuS, and may repreSent a neW
SpecieS. image by SebaStián yancovic pakarati.
a potentially neW and endemic
(family tetr agnathidae) collected Within totora
reedS along the Shore of the crater lake in rano
rar aku. image by SebaStián yancovic pakarati.
recently deScribed iSland endemic SpecieS of
collembola (or Springtail),
Seria manukio
. becauSe
it iS beleived to be reStricted to cave entranceS,
the SpecieS name iS rapa nui for “hiding bug.” image
courteSy bernard et al. 2015,
StyloniScuS manuvaka
iS a recently deScribed
polyneSian endemic SpecieS. named “manuvaka,” rapa
nui for “canoe bug,” thiS SpecieS WaS believed to be
diSperSed by the ancient polyneSianS. preSently, it
iS knoWn only to rapa iti (auStral iSl andS, french
polyneSia) and rapa nui. image courteSy taiti and
Wynne 2015,
th E Ex ploR ERs jo uR na l
insects (the previously mentioned ten
species), this seemed reasonable. Based
on preliminary analysis, we may have
at least seven potentially undescribed
(or new and endemic) species. The
prospective new species include a ter-
restrial isopod (Littorophiloscia sp., Family
Halophilosciidae), one long-jawed orb-
weaving spider (Tetragnatha sp., Family
Tetragnathidae), possibly three different
species of planthoppers (Superfamly
Fulgoroidea), and two fungus weevil
beetle species (Family Anthribidae).
While these animals may indeed
represent species new to science, our
assertions have not run the gauntlet of
scientific process. To unveil these animals
as “new to science,” we must painstak-
ingly cross-reference every diagnostic
taxonomic character of these presumed
new species using taxonomic keys, com-
pare the specimens to available voucher
collections, formally write up our pro-
nouncements, and have the theses vetted
WallS of a cave entrance decorated With petroglyphS
of the cre ator diety, makemake, Sector unai.
photograph by jut Wynne.
through peer-review. It may take two to five
years before any of these species can be
sufficiently cross-examined with closely
related sister species, formally described
(if determined to be new), and the results
published in scientific papers.
We collected at least 20,000 ar-
thropod specimens with many being
infinitesimal. To date, less than 2 percent
of these specimens have been sorted and
analyzed. While a team of undergraduate
students is actively organizing, sorting,
and imaging these specimens, it may take
years for us to characterize the assortment
of specimens we’ve collected. Also, small-
bodied arthropods such as springtails,
psocoptera, and mites are often difficult
to examine in the field, making species-
level identifications painstakingly onerous.
Given our limited knowledge of these
groups on the island and the considerable
number of specimens collected, there are
probably new species awaiting formal
description within these groups. More
surprises are anticipated as we somewhat
glacially process these specimens.
While this project represents the larg-
est study to search for endemic ground-
dwelling insects in some of the most
difficult to access areas, only a fraction of
these island environments were sampled.
I suspect it would take several months
to adequately study the highly heteroge-
neous Rano Kau crater. Although troglo-
bites have not been confirmed, only 30 of
800 known caves have been sampled. So,
they may very well be awaiting our discov-
ery. Additionally, only one of the six motus
surrounding Rapa Nui was previously
sampled. In 2012, a research team spent
a few hours collecting spiders on Motu
Nui. As the motus support native plant
species, have not been populated by rats
and livestock, and serve as rookeries for
pelagic birds, they should be considered
high priority targets for study.
Beyond the science, our greatest con-
tribution was speaking with the Rapa Nui
community concerning the importance of
conservation and management of endem-
ic insects. Francisco Ika and I conducted
radio interviews, spoke with students at
three secondary schools, gave a public
lecture at the Rapa Nui Museum, and par-
ticipated in the production of a 15-minute
documentary chronicling the importance
of this work. Through our efforts, we hope
the Rapa Nui people will ultimately em-
brace these endemic insects as their own.
They, too, are Rapa Nui. Once the Rapa
Nui people “adopt” these insects, I believe
this action will significantly improve their
odds of being protected.
The seven potentially new and endemic
arthropods were uniquely detected in
each of the four environments (caves,
cliffs, coasts, and crater lakes). These
findings further support the hypothesis
that endemic insect species still occur
where habitats are partially protected
from human activities and livestock. From
a more practical perspective, this work
has underscored the importance of ef-
fectively managing and conserving these
environments so both endemic plants and
animals may be protected.
A dwindling handful of plants and
bugs are all that remain of the island’s
ancient ecosystems. Each endemic plant
and insect provides a critical cosmologi-
cal tendril between ancient and modern
Rapa Nui. As we continue our analyses,
I will share our discoveries with national
park officials and the island community.
Over the next several years, we hope
to create far greater awareness of our
findings. As this occurs, my hope is
that protection of the island’s endemic
insect species will grow exponentially in
importance and become an underpinning
theme for natural resource conservation
on the navel of the world.
th E Ex ploR ERs jo uR na l
Realms of species, assemblages, and whole ecosystems are threatened by human activities such as damage, resource use, pollution, introduction of neobiota, and also by natural processes and disasters. We present an assessment of distribution patterns and numbers of endemic and threatened species with respect to their habitat affinity and threats at global and European scales.
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