Host specificity of <Emphasis Type="Italic">Anagrus epos</Emphasis>: a potential biological control agent of <Emphasis Type="Italic">Homalodisca vitripennis</Emphasis>

Anagrus epos Girault (Hymenoptera: Mymaridae) is a candidate for a classical biological control program targeting the glassy-winged sharpshooter (GWSS), Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae), in California. Because mass production of GWSS is expensive and labor-intensive, a factitious host that is more economical to produce is desirable to mass produce A. epos for colonization and augmentation efforts. Here, we report the results of host specificity tests and potential rearing techniques for A. epos under laboratory conditions. Females discriminated and oviposited into eggs of seven cicadellid species: H. vitripennis, Circulifer tenellus (Baker), Erythroneura variabilis Beamer, Amblysellus grex (Oman), Graphocephala atropunctata (Signoret), Macrosteles severini Hamilton, and H. liturata Ball, and two cerambycid species: Phoracantha recurva Newman and P. semipunctata (F.). Anagrus epos successfully completed development in the eggs of H. vitripennis, C. tenellus, E. variabilis, A. grex, G. atropunctata, M. severini, and H. liturata. The use of a factitious host and potential nontarget effects of this generalist parasitoid are discussed.     

Engineering Enemy-free Space: An Invasive Pest that Kills its Predators

The biological invasion of the glassy-winged sharpshooter, Homalodisca coagulata, into French Polynesia presents a novel threat to Pacific Island ecosystems. Widely known as an agricultural pest because of its role as a vector of numerous lethal plant diseases, H. coagulata may pose a substantial and immediate risk to arthropod predators on invaded islands in French Polynesia. Controlled feeding experiments revealed that island spiders can be killed following predation on H. coagulata. Spider mortality appeared to result from lethal intoxication, although no form of chemical defense has been reported in H. coagulata. In the two spider species tested, approximately half of all individuals that attacked H. coagulata nymphs or adults died. As populations of this insect increase in size and range on invaded islands in French Polynesia, H. coagulata will increasingly encounter these and other arthropod predators, raising the possibility of population-level impacts on susceptible predator species. Field surveys of island spiders across nine sites on H. coagulata-invaded and H. coagulata-uninvaded islands suggest that this insect may already have adversely impacted an endemic spider on at least one island. Work is needed to identify the nature of the lethal agent harbored within H. coagulata and the taxonomic and geographic breadth of predators vulnerable to it. The generality of H. coagulata-lethality and the capacity of afflicted predator species for population-level adaptation or learned avoidance in response to this spreading pest will determine the magnitude of the threat H. coagulata poses in the South Pacific.     

Invasion dynamics of the glassy-winged sharpshooter <Emphasis Type="Italic">Homalodisca vitripennis</Emphasis> (Germar) (Hemiptera: Cicadellidae) in French Polynesia

The glassy-winged sharpshooter, Homalodisca vitripennis (Germar) [formerly Homalodisca coagulata (Say)] (Hemiptera: Cicadellidae), has recently emerged as a serious invasive pest. From its natural range in the southeast USA and northeast Mexico, it invaded successively California (late 1980s), French Polynesia (1999), Hawaii (2004), and recently Easter Island (2005) inadvertently through the transportation of infested plants. In French Polynesia, H. vitripennis has reached impressive densities becoming an important pest threatening agriculture, native biodiversity, as well as being a major social nuisance. Since 1999, H. vitripennis spread rapidly from Tahiti to neighboring islands, colonizing most of the archipelagos of French Polynesia. In this paper, we present the results of surveys of H. vitripennis populations from 15 islands of French Polynesia and use these data to investigate the invasion dynamics and colonization processes of this pest in a tropical climate. We found H. vitripennis present in 10 islands with two new records confirmed. Our analyses suggest that: (1) H. vitripennis abundance is strongly associated with urbanization, with highest pest densities found in the most developed coastal areas of infested islands, (2) H. vitripennis may exhibit an Allee effect during the early phase of an invasion, and (3) the invasion dynamics of H. vitripennis conform to a stratified dispersal model marked by rapid long-distance human-mediated movement.     

Characterization of cell lines developed from the glassy-winged sharpshooter, Homalodisca coagulata (hemiptera: Cicadellidae)

Summary Four continuous cell lines were established from the embryos of the glassy-winged sharpshooter, Homalodisca coagulata (Say), an economically important insect vector of bacterial pathogens of grape, almond citrus, oleander, and other agricultural and ornamental plantings. The cell lines were designated GWSS-Z10, GWSS-Z15, GWSS-G3, and GWSS-LH. The GWSS-Z10, GWSS-Z15, and GWSS-G3 lines were cultured in Ex-Cell 401 medium supplemented with 10% fetal bovine serum (FBS), whereas the GWSS-LH line was cultured in LH medium supplemented with 20% FBS. The cell lines were characterized in terms of their morphology, growth, protein composition, and polymerase chain reactionamplification patterns of their chromosomal deoxyribonucleic acid. The population doubling times of GWSS-Z10, GWSS-Z15, GWSS-G3, and GWSS-LH were 46.2, 90.9, 100.3 and 60.2 h, respectively. These lines should be useful for the study of insect-pathogenic viruses of leafhoppers, aphids, treehoppers, and other related insects as well as plant-pathogenic viruses that are transmitted by these insects.     

Design of grapevine (Vitis vinifera L.) cultivar-specific SCAR primers for PCR fingerprinting

Among 34 grapevine cultivars (Vitis vinifera L.), eight putative genotype-specific RAPD markers, from ’Albariño’, ’Caíño blanco’, ’Chardonnay’, ’Folle blanche’, ’Grenache blanc’, ’Malvasía Sitges’, ’Torrontés’ and ’Treixadura’ respectively, were selected to transform into SCAR markers. Of these, seven markers were cloned and then five which showed a positive specific hybridization signal were sequenced. For these five markers, 30 sequence-specific primers ranging from 14 to 29 bases were designed to amplify genomic DNA from 64 grapevine cultivars under more-stringent PCR conditions. Only, two primer pairs, OpA11₁₁₇₅p17R/ p17F and OpD10₈₀₀p14R/p14F, still produced a specific SCAR marker, the ’Folle blanche’ ScA11₁₁₇₅ and the ’Malvasía Sitges’ ScD10₈₀₀ respectively. Moreover, the ScA11₁₁₇₅ marker was amplified only in ’Folle blanche’ among the 64 cultivars tested with a large annealing temperature range using either two different Taq DNA polymerases or two separate thermocyclers. In addition, we discuss the initial polymorphism originated by the RAPD technique and suggest a new design of SCAR primers to obtain reliable cultivar-specific SCAR markers from single PCR-based bands for identification purposes.     

Development of strain-specific SCAR markers for authentication of Ganoderma lucidum

In this study we report the application of sequence-characterized amplified region (SCAR) markers in Ganoderma lucidum for strain identification, the first such study in this medicinal mushroom. One fragment unique to strain No. 9 was identified by inter-simple sequence repeats (ISSR), and then sequenced. Based on the specific fragment, one SCAR primer pair designated as GL₆₁₂F and GL₆₁₂R was designed to amplify a 612-bp DNA fragment within the sequenced region. Diagnostic PCR was performed using the primer pair. The results showed that this SCAR marker can clearly distinguish strain No. 9 from other related Ganoderma lucidum strains. Our data provided the foundation for a precise and rapid PCR-based strain-diagnostic system for Ganoderma lucidum.     

Development of a SCAR marker and a strain‐specific genomic marker for the detection of the biocontrol agent strain CPA‐8 Bacillus amyloliquefaciens (formerly B. subtilis)

In this work, reliable tools were developed to detect and identify the biocontrol strain CPA‐8 using DNA amplification techniques. As a first approach, the RAPD (random amplified polymorphic DNA) technique was applied to a collection of 77 related Bacillus species. Among the primers tested, the primer pair OPG1/OPG6 amplified a 668 bp specific product to the strain CPA‐8 that was sequenced and used to design SCAR (sequence‐characterised amplified regions) primer pairs. The SCAR‐4 marker amplified a semi‐specific fragment of 665 bp not only for the strain CPA‐8 but also for other 12 strains whose morphology was completely different from CPA‐8. Another approach was developed to obtain a strain‐specific genomic marker related to ecological adaptations of Bacillus amyloliquefaciens species. The primer pair F2/R2 obtained from RBAM 007760, a gene involved in surface adhesion, amplified a 265 bp fragment unique for strain CPA‐8. Our results revealed that these two molecular markers, SCAR‐4 and RBAM 007760 F2/R2 provide suitable monitoring tools to specifically identify the biocontrol CPA‐8 when applied against brown rot caused by Monilinia spp. in stone fruit. Moreover, our findings demonstrate that the strain CPA‐8 is affiliated with B. amyloliquefaciens species that was formerly designated as Bacillus subtilis.     

A Plating‐PCR Technique for Detection and Quantification of the Biological Control Agent Agrobacterium vitis Strain E26 in Soil under Controlled Conditions

Agrobacterium vitis strain E26 is a promising biocontrol agent of grapevine crown gall, an economically important disease of grape worldwide. In this report, we developed a Plating‐PCR method that allows specific detection and quantification of E26 by combining classical microbiological techniques with molecular tools. Random amplified polymorphic DNA fingerprints were used to differentiate E26 from other A. vitis strains. A differentially amplified fragment from E26 was sequenced and characterized as a sequence characterized amplified region (SCAR) marker. Two primer pairs were then designed and evaluated for their specificity against E26. One of the two SCAR primer pairs, 740F/R, was further selected for specific detection of strain E26. A plating assay coupled to PCR with the SCAR primers 740F/R allowed the assessment of population dynamics of E26 in non‐sterile grape rhizosphere soil under controlled conditions.     

CHARACTERIZATION OF GENETIC MARKERS LINKED TO SEX DETERMINATION IN THE HAPLOID‐DIPLOID RED ALGA GRACILARIA CHILENSIS1

Bulk segregant analysis, random amplified polymorphic DNA (RAPD), and sequence characterized amplified region (SCAR) methods were used to identify sex‐linked molecular markers in the haploid‐diploid rhodophyte Gracilaria chilensis C. J. Bird, McLachlan et E. C. Oliveira. One hundred and eighty 10 bp primers were tested on three bulks of DNA: haploid males, haploid females, and diploid tetrasporophytes. Three RAPD primers (OPD15, OPG16, and OPN20) produced male‐specific bands; and one RAPD primer (OPD12), a female‐specific band. The sequences of the cloned putative sex‐specific PCR fragments were used to design specific primers for the female marker SCAR‐D12‐386 and the male marker SCAR‐G16‐486. Both SCAR markers gave unequivocal band patterns that allowed sex and phase to be determined in G. chilensis. Thus, all the females presented only the female band, and all the males only the male band, while all the tetrasporophytes amplified both male and female bands. Despite this sex‐specific association, we were able to amplify SCAR‐D12‐386 and SCAR‐G16‐486 in both sexes at low melting temperature. The differences between male and female sequences were of 8%–9% nucleotide divergence for SCAR‐D12‐386 and SCAR‐G16‐486, respectively. SCAR‐D12‐386 and SCAR‐G16‐486 could represent degenerated or diverged sequences located in the nonrecombining region of incipient sex chromosomes or heteromorphic sex chromosomes with sequence differences at the DNA level such that PCR primers amplify only one allele and not the other in highly specific PCR conditions. Seven gametic progenies composed of 19 males, 19 females, and the seven parental tetrasporophytes were analyzed. In all of them, the two SCAR markers segregated perfectly with sexual phenotypes.     

Propagation of Homalodisca coagulata virus-01 via Homalodisca vitripennis Cell Culture

The glassy-winged sharpshooter (Homalodisca vitripennis) is a highly vagile and polyphagous insect found throughout the southwestern United States. These insects are the predominant vectors of Xylella fastidiosa (X. fastidiosa), a xylem-limited bacterium that is the causal agent of Pierce''s disease (PD) of grapevine. Pierce’s disease is economically damaging; thus, H. vitripennis have become a target for pathogen management strategies. A dicistrovirus identified as Homalodisca coagulata virus-01 (HoCV-01) has been associated with an increased mortality in H. vitripennis populations. Because a host cell is required for HoCV-01 replication, cell culture provides a uniform environment for targeted replication that is logistically and economically valuable for biopesticide production. In this study, a system for large-scale propagation of H. vitripennis cells via tissue culture was developed, providing a viral replication mechanism. HoCV-01 was extracted from whole body insects and used to inoculate cultured H. vitripennis cells at varying levels. The culture medium was removed every 24 hr for 168 hr, RNA extracted and analyzed with qRT-PCR. Cells were stained with trypan blue and counted to quantify cell survivability using light microscopy. Whole virus particles were extracted up to 96 hr after infection, which was the time point determined to be before total cell culture collapse occurred. Cells were also subjected to fluorescent staining and viewed using confocal microscopy to investigate viral activity on F-actin attachment and nuclei integrity. The conclusion of this study is that H. vitripennis cells are capable of being cultured and used for mass production of HoCV-01 at a suitable level to allow production of a biopesticide.     

Use of life table statistics and degree-day values to predict the invasion success of Gonatocerus ashmeadi (Hymenoptera: Mymaridae), an egg parasitoid of Homalodisca coagulata (Hemiptera: Cicadellidae), in California

Life table statistics and degree-day requirements for Gonatocerus ashmeadi Girault, a parasitoid of the glassy-winged sharpshooter Homalodisca coagulata (Say), were used to estimate the number of expected parasitoid generations in California (USA). Between two to 51 and one to 37 generations per year were estimated across different climatic regions in California, using life table and degree-day models, respectively. Temperature-based values for net reproductive rate, R_o, were estimated in California using a laboratory-derived equation and ranged from zero to approximately 48 and analyses indicate that a minimum of eight generations are required each year to sustain a population increase of G. ashmeadi. Long-term weather data from 381 weather stations across California were used with an Inverse-Distance Weighting algorithm to map temperature-based estimations for the entire state of California. This Geographic Information Systems model was used to determine number of G. ashmeadi generations based on day-degree accumulation, T_c, and R_o. GIS mapping indicated that Californian counties in the north, central west coast, central west and Sierra Nevada regions may be climatic conditions unfavorable for supporting the permanent establishment of invading populations of G. ashmeadi should H. coagulata successfully establish year-round populations in these areas. Southern counties in California that experience warmer year round temperatures and support year round populations of H. coagulata, appear to be conducive to the establishment of permanent populations of G. ashmeadi. The mechanisms facilitating G. ashmeadi invasion and the implications of these temperature-based estimates for biological control of H. coagulata are discussed.     

Biology and host specificity of <Emphasis Type="Italic">Gonatocerus deleoni</Emphasis> (Hymenoptera: Mymaridae), a potential biocontrol agent of <Emphasis Type="Italic">Homalodisca vitripennis</Emphasis> (Hemiptera: Cicadellidae) in California,USA

The host-specificity and biological traits of Gonatocerus deleoni Triapitsyn, Logarzo & Virla (Hymenoptera: Mymaridae), a potential candidate for biological control of the glassy-winged sharpshooter (GWSS), Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae), were determined under laboratory conditions. G. deleoni is a solitary egg parasitoid native to Argentina, originally reared from sentinel eggs of Tapajosa rubromarginata (Signoret) (Cicadellidae). With GWSS as a fictitious host, G. deleoni’s average development time from oviposition to adult emergence was 18.8 ± 1.4 days, with males developing faster than females (18.0 ± 1.3 days, males; 19.0 ± 1.3 days, females). The average parasitism rate on 1–8-day-old eggs was 45.7% but this was significantly affected by the age of the egg, ranging from 1.4% to 69.9% (egg ages 8 and 3, respectively). The average sex ratio was 0.34 (percent males) and sex ratio was not significantly affected by egg age. G. deleoni was able to develop in eggs of GWSS and Homalodisca liturata Ball (both in the tribe Proconiini), but was unable to develop on eggs of Graphocephala atropunctata (Signoret) (different tribe, same subfamily) or Erythroneura elegantula Osborn (different subfamily).     

Gut content examination of the citrus predator assemblage for the presence of Homalodisca vitripennis remains

A two-year study was conducted in a citrus orchard, Citrus sinensis L., to determine frequency of predation on glassy-winged sharpshooter (GWSS), Homalodisca vitripennis (Germar). A total of 1,578 arthropod predators, representing 18 taxa, were collected and assayed for the presence of GWSS egg protein by an enzyme-linked immunosorbent assay using a Homalodisca-species and egg-specific monoclonal antibody and then by polymerase chain reaction using a H. vitripennis-specific DNA marker. The gut content analyses revealed the presence of GWSS remains in the gut of 2.28 % of the total arthropod predator population, with 3.09 % of the spiders and 0.59 % of the insect predators testing positive. Moreover, a comparison of the two assays indicated that they were not equally effective at detecting GWSS remains in predator guts. Low frequencies of GWSS detection in the gut of predators indicated that GWSS are not a primary prey and that predators may contribute little to suppression of this pest in citrus.     

Molecular characterization of a ChaC K+ transport regulator gene and its transcripts in the glassy-winged sharpshooter,Homalodisca coagulata

Four mRNA variants in pooled cDNA samples of the glassy-winged sharpshooter, Homalodisca coagulata, encoding a putative regulator of cation transporters were identified. RT-PCR showed that the hc-chaC variants were expressed during different stages of insect development and in different tissues and sexes. Structural analysis of the hc-chaC gene indicated that intron and exon sequences of the mRNA variants were identical, and similar to chaC-like genes of other insects. The Hc-ChaC protein (22.5 kDa) contained the conserved FGYGSL K⁺-binding motif near its amino-terminus, and the carboxy-terminal region contained two coiled-coil motifs, which had similarity to the PDZ domain present in well-characterized Na⁺/H⁺ exchanger regulatory factors. Our analyses suggest that Hc-ChaC is a regulator of K⁺ transporters such as K⁺/H⁺ antiporters.     

Delivery of a Genetically Marked <Emphasis Type="Italic">Alcaligenes</Emphasis> sp. to the Glassy-Winged Sharpshooter for Use in a Paratransgenic Control Strategy

An artificial feeding system was designed for the glassy-winged sharpshooter (GWSS), Homalodisca coagulata Say (Hemiptera: Cicadellidae). The system, unlike previous systems, provided enough nutrients to GWSS to survive for 48 h. A system like this is a prerequisite to examining the potential use of paratransgenesis to interrupt transmission of Xylella fastidiosa, the bacterial pathogen causing Pierces disease of grape, by insect vectors. We developed a system for short-term feeding of GWSS that allows for the introduction of bacteria in liquid medium, and we have demonstrated the ability of Alcaligenes xylosoxidans denitrificans, expressing a red fluorescent protein (dsRed), to colonize the cibarial region of the GWSS foregut for up to 5 weeks post-exposure. Alcaligenes xylosoxidans denitrificans thus occupies the same region in the foregut as the pathogen, Xylella fastidiosa.     

Transmission of Pantoea agglomerans—A paratransgenic control agent—Within a Homalodisca vitripennis population

Paratransgenic control of pests can be an alternative to chemical control, which is associated with environmental contamination, and higher input cost. We have recently developed paratransgenic control strategy to block transmission of the Pierce's disease pathogen—Xylella fastidiosa by its arthropod vector—Homalodisca vitripennis (the glassy-winged sharpshooter) using antimicrobial peptide-expressing strains of Pantoea agglomerans. In the present study, we report horizontal transmission of one of such P. agglomerans strains from H. vitripennis. This process indicates that P. agglomerans can self-sustain in a population of H. vitripennis and, thus, can provide paratransgenic control of X. fastidiosa in field. These results also provide basis for future field studies.     

Engineering an invasion: classical biological control of the glassy-winged sharpshooter, <Emphasis Type="Italic">Homalodisca vitripennis</Emphasis>, by the egg parasitoid <Emphasis Type="Italic">Gonatocerus ashmeadi</Emphasis> in Tahiti and Moorea,French Polynesia

The glassy-winged sharpshooter, Homalodisca vitripennis Germar (=H. coagulata Say) (Hemiptera: Cicadellidae), invaded Tahiti in 1999 and spread rapidly to the main island groups of French Polynesia becoming an important pest. It threatened agriculture, native biodiversity, and created serious social and recreational problems. Further, massive uncontrolled populations on Tahiti presented an elevated invasion threat to other South Pacific nations. In 2004, a classical biological control program against H. vitripennis was initiated in French Polynesia using the highly host-specific egg parasitoid Gonatocerus ashmeadi Girault (Hymenoptera: Mymaridae). After risk assessment studies indicated an acceptably low level of risk to non-target species, 13,786 parasitoids were released at 27 sites in Tahiti between May and October 2005. Here we present the results of G. ashmeadi and H. vitripennis population surveys during the first year of their interaction in French Polynesia (until mid-May 2006). The impact of G. ashmeadi on H. vitripennis was extremely rapid and high. Parasitism of H. vitripennis egg masses by G. ashmeadi has averaged 80–100% in Tahiti since the introduction of the parasitoid, and populations of H. vitripennis nymphs and adults have decreased by more than 90% since December 2005. Populations of H. vitripennis have been successfully maintained at this low level for more than 1 year. The same results were obtained in nearby Moorea where the parasitoid was probably spread by the unregulated transport of plants infested with parasitized H. vitripennis eggs. Population monitoring continues in order to determine if a stable equilibrium between the pest and the parasitoid has been reached.     

Brochosome influence on parasitisation efficiency of Homalodisca coagulata (Say) (Hemiptera: Cicadellidae) egg masses by Gonatocerus ashmeadi Girault (Hymenoptera: Mymaridae)

Abstract. 1. Many cicadellid females in the tribe Proconiini (Hemiptera: Cicadellidae) cover their egg masses with specialised, usually rod‐shaped, brochosomes as the eggs are being laid. The brochosomes are produced in Golgi complexes in the Malpighian tubules of Cicadellidae. In contrast to the gravid females, adult males, pre‐reproductive adult females, and nymphal males and females produce specialised, usually spherically shaped brochosomes. Brochosomes are also used to cover the external surfaces of nymphs and newly moulted adult males and females. 2. The function of the brochosome covering the egg masses is unknown but various hypotheses have been suggested, including protecting the eggs against pathogens, predators, and parasitoids. Based on preliminary observations of Gonatocerus ashmeadi Girault (Hymenoptera: Mymaridae) parasitising the eggs of the cicadellid, Homalodisca coagulata (Say), it is speculated here that brochosomes covering an egg mass hinder parasitisation of eggs by G. ashmeadi. This hypothesis was tested by observing G. ashmeadi females foraging on leaves with H. coagulata egg masses heavily covered with rod‐shaped brochosomes vs. those lacking brochosomes. 3. Cox's proportional hazards model was used to evaluate the probability, per unit time, that a female G. ashmeadi displayed the sequence of behaviours that ended in successful oviposition as influenced by five variables: (a) presence or absence of brochosomes on an egg mass, (b) the leaf surface, upper or lower, being searched by the parasitoid (the egg masses are laid in the parenchyma on the lower leaf surface), (c) the parasitoid's previous ovipositional experience, (d) egg mass size, and (e) the parasitoid's age. 4. Brochosomes significantly decreased oviposition efficacy of G. ashmeadi females. Scanning electron microscopy showed that females exposed to brochosome‐covered egg masses had brochosomes adhering to their tarsi, legs, antennae, and eyes, all of which prompted extensive bouts of grooming.     

Classical biological control of the glassy-winged sharpshooter,Homalodisca vitripennis,by the egg parasitoid Gonatocerus ashmeadi in the Society,Marquesas and Austral archipelagos of French Polynesia

The glassy-winged sharpshooter, Homalodisca vitripennis (Germar) (= H. coagulata [Say]) (Hemiptera: Cicadellidae), was a major exotic pest in French Polynesia until a classical biological control program against this pest was conducted using the host-specific egg parasitoid Gonatocerus ashmeadi Girault (Hymenoptera: Mymaridae). After risk assessment studies indicated an acceptably low potential threat to non-target species, parasitoids were released on Tahiti in May 2005. One year after release, populations of H. vitripennis had decreased by more than 90% in Tahiti and nearby Moorea. Here we present results of impact studies obtained during the second post-release year for G. ashmeadi in Tahiti and Moorea; we also report for the first time on results for eight other H. vitripennis infested islands located in three different archipelagos (Society, Marquesas, and Austral) of French Polynesia. On all infested islands across the three archipelagos, arrival of G. ashmeadi slashed H. vitripennis densities by more than 95%. In Tahiti and Moorea, H. vitripennis populations were maintained at very low densities during the second post-release year. Seasonal fluctuations of H. vitripennis abundance were observed in Tahiti with pest populations being more abundant during the cooler dry season than during the warmer wet season because of lower parasitism rates. Hence, similar seasonal fluctuations of H. vitripennis abundance are expected across all infested archipelagos in French Polynesia.