Papers by Jean-Lou Justine

HAL (Le Centre pour la Communication Scientifique Directe), 2009
The following members of the genus Hypocreadium are described or redescribed: Hypocreadium cavum ... more The following members of the genus Hypocreadium are described or redescribed: Hypocreadium cavum from the starry triggerfish, Abalistes stellatus, Swain Reefs, Great Barrier Reef; Hypocreadium patellare 'Typical form' from Abalistes stellatus, Swain Reefs, the masked triggerfish, Sufflamen fraenatum, Ningaloo, Western Australia and off New Caledonia and the titan triggerfish, Balistoides viridescens, off Lizard Island, Great Barrier Reef; Hypocreadium patellare 'Atypical form A' from the black-bar triggerfish, Rhinecanthus aculeatus, off Lizard Island and Palau and blackbelly triggerfish, R. verrucosus, off Palau; Hypocreadium patellare 'Atypical form B' from the yellow-spotted triggerfish, Pseudobalistes fuscus off Lizard Island; Hypocreadium picasso n. sp. from Rhinecanthus aculeatus, off Lizard Island and Palau, characterised by its broadly pyriform shape and lack of an anterior notch. A key to the species of Hypocreadium is presented. The similarity of the genus Lutianotrema to Hypocreadium is pointed out, but both known species of Lutianotrema are described with 'dorsal' oral suckers.

Systematic Parasitology, Jan 30, 2019
Parasite biodiversity of fish of the southern part of the Mediterranean sea is still incompletely... more Parasite biodiversity of fish of the southern part of the Mediterranean sea is still incompletely explored. We describe here Microcotyle visa n. sp. from the gill filaments of the bluespotted seabream Pagrus caeruleostictus (Valenciennes) (Sparidae) collected off the Algerian coast. The identity of fish hosts was confirmed by barcoding. Microcotyle visa n. sp. is herein described and illustrated. Analysis of the cox1 gene of the monogeneans revealed minor intraspecific variation (1.4%), an order of magnitude lower than the distance between this species and other Microcotyle species (10-15 %). Microcotyle visa n. sp. is distinguished from Microcotyle erythrini van Beneden & Hesse, 1863, a congener infesting sparids, on the basis of morphological (size of clamps, number of testes) and molecular (cox1) differences. This is the fourth member of the genus known to parasitise a sparid host. A species of Paramicrocotyle sp. included in the molecular analysis was nested within a robust Microcotyle + Paramicrocotyle clade; in the absence of demonstrated molecular and morphological differences, we consider that Paramicrocotyle Caballero & Bravo-Hollis, 1972 is a junior synonym of Microcotyle van Beneden & Hesse, 1863 and transfer two species of Paramicrocotyle as Microcotyle danielcarrioni (Martinez & Barrantes, 1977) n. comb. and Microcotyle moyanoi (Villalba & Fernandes, 1986) n. comb.

PeerJ, Aug 16, 2016
Little is known of the diversity of the monogenean parasites infesting deep-sea groupers, and the... more Little is known of the diversity of the monogenean parasites infesting deep-sea groupers, and there is even less information available about their geographic distributions within the ranges of their hosts. To improve our understanding of these hostparasite relationships we conducted parasitological evaluations of the deep-water Haifa grouper Hyporthodus haifensis from the southern Mediterranean off Tunisia and Libya. We collected more than one species of diplectanid monogeneans from this host, but among these only one dominant species was abundant. This proved to be morphologically very similar to Pseudorhabdosynochus sulamericanus Santos, Buchmann & Gibson, 2000, a species originally described from the congeneric host H. niveatus off Brazil and also recorded from H. niveatus and H. nigritus off Florida. Here, we conducted a morphological comparison between newly collected specimens and those previously deposited in museum collections by other authors. Further, we used COI barcoding to ascertain the specific identity of the three host species to better elucidate the circumstances that might explain the unexpectedly broad distribution of P. sulamericanus. We assigned our specimens from H. haifensis to P. sulamericanus primarily on the basis of morphological characteristics of the sclerotized vagina. We also noted morphological characteristics of eastern and western Atlantic specimens that are not clearly described or not given in previous descriptions and so prepared a redescription of the species. We confirmed, by COI barcoding, that no sister-species relationships were evident among the three hosts of P. sulamericanus. Our observation that P. sulamericanus infects unrelated host species with putatively allopatric distributions was unexpected given the very limited dispersive capabilities and the high degree of host specificity common to members of Pseudorhabdosynochus. How to cite this article Chaabane et al. (2016), Pseudorhabdosynochus sulamericanus (Monogenea, Diplectanidae), a parasite of deep-sea groupers (Serranidae) occurs transatlantically on three congeneric hosts (Hyporthodus spp.), one from the Mediterranean Sea and two from the western Atlantic. PeerJ 4:e2233;
Systematic Parasitology, Oct 1, 2019
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
HAL (Le Centre pour la Communication Scientifique Directe), 2009
Parasite, 2021
Cyclocotyla bellones Otto, 1823 (Diclidophoridae) is a monogenean characterised by an exceptional... more Cyclocotyla bellones Otto, 1823 (Diclidophoridae) is a monogenean characterised by an exceptional way of life. It is a hyperparasite that attaches itself to the dorsal face of isopods, themselves parasites in the buccal cavity of fishes. In this study, Cy. bellones was found on Ceratothoa parallela (Otto, 1828), a cymothoid isopod parasite of the sparid fish Boops boops off Algeria in the Mediterranean Sea. We provide, for the first time, molecular barcoding information of a hyperparasitic monogenean, the parasitic crustacean host, and the fish host, with COI sequences.

Parasitology Research, May 11, 2021
Many Pauciconfibula spp. have a long and complicated taxonomic history. The remaining unsolved ta... more Many Pauciconfibula spp. have a long and complicated taxonomic history. The remaining unsolved taxonomic confusion in this genus is impelled by the host range and status of Pauciconfibula spp. from trachinid fishes: Pauciconfibula trachini and Pauciconfibula draconis, from Trachinus radiatus and Trachinus draco (Trachinidae), respectively. Pauciconfibula trachini was reported on Trachinus draco, type host of Pauciconfibula draconis suggesting thus a stenoxenic specificity for the former monogenean and the occurrence of two congeneric polyopisthocotyleans on a single host. Moreover, the validity of Pauciconfibula draconis was repeatedly questioned by several authors, unjustified synonymy between the two species was proposed, and the delimitations between the two species remained unsolved. Original descriptions were also incomplete and poorly illustrated. In this study, we provide a detailed illustrated redescription of both species based on newly collected specimens of Pauciconfibula trachini and Pauciconfibula draconis collected from their type hosts from off three Mediterranean localities: Algeria, Tunisia, and Italy. Integrative taxonomy using COI sequences was applied to resolve the delimitation between Pauciconfibula trachini and P. draconis. This study provides the first DNA barcoding for members of this genus.

PeerJ, Feb 6, 2020
Background: Obama nungara is a species of land flatworm originating from South America; the speci... more Background: Obama nungara is a species of land flatworm originating from South America; the species was recently described and distinguished from a similar species, Obama marmorata. Obama nungara has invaded several countries of Europe, but the extent of the invasion has not been thoroughly mapped. Methods: In this article, based on a five and a half-year survey undertaken by citizen science, which yielded 530 records from 2013 to 2018, we analysed information about the invasion of Metropolitan France by O. nungara. We also investigated the variability of newly obtained cytochrome c oxidase 1 (COI) sequences of specimens from France, Italy and Switzerland. Results: Obama nungara was recorded from 72 of the 96 Departments of Metropolitan France. The species is especially abundant along the Atlantic coast, from the Spanish border to Brittany, and along the Mediterranean coast, from the Spanish border to the Italian border. More than half of the records were from an altitude below 50 m, and no record was from above 500 m; mountainous regions such as the Alps, Pyrenees and Massif Central are not invaded. Local abundance can be impressive, with 100 of specimens found in a small garden. An analysis of our new COI sequences, combined with published sequences of specimens from several countries, confirmed that three clades comprise the species. The first clade, 'Brazil', is currently confined to this country in South America; the second clade, 'Argentina 2', was found in Argentina and in Europe, only in Spain; and the third, 'Argentina 1', was found in Argentina and in Europe, in Spain,
Parasitology Research, Mar 26, 2019
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

PLOS ONE, Aug 17, 2016
Pseudorhabdosynochus Yamaguti, 1958 is a species-rich diplectanid genus, mainly restricted to the... more Pseudorhabdosynochus Yamaguti, 1958 is a species-rich diplectanid genus, mainly restricted to the gills of groupers (Epinephelidae) and especially abundant in warm seas. Species from the Mediterranean are not fully documented. Two new and two previously known species from the gills of Mycteroperca spp. (M. costae, M. rubra, and M. marginata) in the Mediterranean and Eastern Atlantic Ocean are described here from new material and slides kept in collections. Identifications of newly collected fish were ascertained by barcoding of cytochrome c oxidase subunit I (COI) sequences. Pseudorhabdosynochus beverleyburtonae (Oliver, 1984) Kritsky & Beverley-Burton, 1986 and P. sosia Neifar & Euzet 2007 are redescribed from type-specimens and new specimens collected off Tunisia and Libya from M. marginata and M. costae, respectively. Pseudorhabdosynochus oliveri n. sp., from M. marginata (type-host) off the Mediterranean coast of France (type-locality), is described from specimens found among voucher specimens of P. beverleyburtonae deposited by Guy Oliver in the collection of the Muséum National d'Histoire Naturelle, Paris. Pseudorhabdosynochus oliveri is distinguished by the shape of its sclerotised vagina; it was not found in the other localities investigated. Pseudorhabdosynochus hayet n. sp. is described from M. rubra (type host) off Senegal (type-locality) and Tunisia. Pseudorhabdosynochus hayet is morphologically similar to P. sosia (type-host: M. costae) but was distinguished by differences in measurements of the vagina and male copulatory organ, different host, and divergent COI sequences. The four species (P. beverleyburtonae, P. sosia, P. oliveri, and P. hayet) share common characteristics such as squamodiscs with 2 innermost circular rows PLOS ONE |
HAL (Le Centre pour la Communication Scientifique Directe), 2007
HAL (Le Centre pour la Communication Scientifique Directe), 2010
Five species of the genus Multitestis are described, figured or discussed: Multitestis pyriformis... more Five species of the genus Multitestis are described, figured or discussed: Multitestis pyriformis from Platax orbicularis off Lizard Island, northern Great Barrier Reef, Australia and Platax teira off New Caledonia; Multitestis coradioni n. sp.(syn. Multitestis pyriformis Machida, 1963 of Bray et al.(1994)) from Coradion chrysozonus off Heron Island, which differs from M. pyriformis in its oval body-shape, the more posteriorly situated testicular fields and larger eggs, Multitestis elongatus from Platax pinnatus off Lizard Island, Multitestis ...

PeerJ, May 22, 2018
Background: Species of the genera Bipalium and Diversibipalium, or bipaliines, are giants among l... more Background: Species of the genera Bipalium and Diversibipalium, or bipaliines, are giants among land planarians (family Geoplanidae), reaching length of 1 m; they are also easily distinguished from other land flatworms by the characteristic hammer shape of their head. Bipaliines, which have their origin in warm parts of Asia, are invasive species, now widespread worldwide. However, the scientific literature is very scarce about the widespread repartition of these species, and their invasion in European countries has not been studied. Methods: In this paper, on the basis of a four year survey based on citizen science, which yielded observations from 1999 to 2017 and a total of 111 records, we provide information about the five species present in Metropolitan France and French overseas territories. We also investigated the molecular variability of cytochromeoxidase 1 (COI) sequences of specimens. Results: Three species are reported from Metropolitan France: Bipalium kewense, Diversibipalium multilineatum, and an unnamed Diversibipalium 'black' species. We also report the presence of B. kewense from overseas territories, such as French
HAL (Le Centre pour la Communication Scientifique Directe), Jun 21, 2021

Parasitology, 2022
The taxonomy of species of Bivesicula Yamaguti, 1934 is analysed for samples from holocentrid, mu... more The taxonomy of species of Bivesicula Yamaguti, 1934 is analysed for samples from holocentrid, muraenid and serranid fishes from Japan, Ningaloo Reef (Western Australia), the Great Barrier Reef (Queensland), New Caledonia and French Polynesia. Analysis of three genetic markers (cox1 mtDNA, ITS2 and 28S rDNA) identifies three strongly supported clades of species and suggests that Bivesicula as presently recognized is not monophyletic. On the basis of combined morphological, molecular and biological data, 10 species are distinguished of which five are proposed as new. Bivesicula Clade 1 comprises seven species of which three are effectively morphologically cryptic relative to each other; all seven infect serranids and four also infect holocentrids. Bivesicula Clade 2 comprises three species of which two are effectively morphologically cryptic relative to each other; all three infect serranids and one also infects a muraenid. Bivesicula Clade 3 comprises two known species from apogonid...

Folia Parasitologica, 2021
Based on light and electron microscopical studies, a new nematode parasite, Echinocephalus inserr... more Based on light and electron microscopical studies, a new nematode parasite, Echinocephalus inserratus sp. n. (Spirurida: Gnathostomatidae), is described from the spiral valve of the broad cowtail stingray Pastinachus ater (Macleay) (Dasyatidae, Myliobatiformes) from off New Caledonia. The new species is morphologically and biometrically most similar to Echinocephalus overstreeti Deardorff et Ko, 1983, differing from it mainly in the absence of serrations on the posterior parts of pseudolabia and on interlabia, and in having a longer gubernaculum (150-299 µm long). Morphologically unidentifiable, mostly encapsulated larvae of Echinocephalus spp. were recorded from the following six species of teleost fishes collected in New Caledonian waters, serving as paratenic hosts: Perciformes: Acanthopagrus berda (Forsskål) (Sparidae) and Nemipterus furcosus (Valenciennes) (Nemipteridae); Tetraodontiformes: Abalistes stellatus (Anonymous), Pseudobalistes fuscus (Bloch et Schneider) (both Balistidae), Lagocephalus sceleratus (Gmelin) (Tetraodontidae) and Aluterus monoceros (Linnaeus) (Monacanthidae). Co-parasitising larvae of Ascarophis sp. and Hysterothylacium sp. were also collected from P. fuscus. All these findings represent new host and geographical records. A key to valid species of Echinocephalus Molin, 1858 is provided.
Alien land flatworms (family Geoplanidae) are invading many countries in the world. Some can easi... more Alien land flatworms (family Geoplanidae) are invading many countries in the world. Some can easily be identified by their morphology and colour pattern, but some are more cryptic and necessitate a molecular approach. Caenoplana decolorata Mateos et al., 2020 was recently described, from specimens found in Spain, as a sibling species to C. coerulea Moseley, 1877. We found that one specimen collected in Nantes, France in 2014 had a 100% identity of its COI sequence with one specimen of the original description of C. decolorata, and thus we record here the species for the first time in France.

Parasite, 2020
The ultrastructure of the mature spermatozoa of Tergestia clonacantha and T. laticollis collected... more The ultrastructure of the mature spermatozoa of Tergestia clonacantha and T. laticollis collected from the digestive tracts of fishes from New Caledonia is described using transmission electron microscopy and compared to that of related species. The spermatozoa of the two species exhibit the general pattern described in most digeneans, namely two axonemes with the 9 + “1” pattern of the Trepaxonemata, nucleus, mitochondrion, cortical microtubules, an external ornamentation of the plasma membrane, spine-like bodies and granules of glycogen. The spermatozoa of T. clonacantha and T. laticollis show the same ultrastructural model with some specificities in each case, particularly in the disposition of the structures in the posterior extremities of the spermatozoon. This study confirms that ultrastructural characters of the mature spermatozoon are useful tools for the phylogenetic analysis of the Digenea.
Systematic Parasitology, 2020
The diclidophorid Flexophora ophidii Prost & Euzet, 1962, the type-and only species of the genus ... more The diclidophorid Flexophora ophidii Prost & Euzet, 1962, the type-and only species of the genus Flexophora Prost & Euzet, 1962, has never been redescribed neither reported since its original description. The latest lacked a diagnosis of the genus that remains unavailable to date. Flexophora ophidii is redescribed and illustrated based on examination of new material from the type-host Ophidion barbatum L. (Ophidiiformes: Ophidiidae) collected off the Algerian coast (new geographical record), southern Mediterranean. A diagnosis of the genus is provided. This article is part of the Topical Collection Monogenea.

Parasite, 2020
The presence/absence and number of vaginae is a major characteristic for the systematics of the M... more The presence/absence and number of vaginae is a major characteristic for the systematics of the Monogenea. Three gastrocotylid genera share similar morphology and anatomy but are distinguished by this character:PseudaxineParona & Perugia, 1890 has no vagina,AllogastrocotyleNasir & Fuentes Zambrano, 1983 has two vaginae, andPseudaxinoidesLebedev, 1968 has multiple vaginae. In the course of a study ofPseudaxine trachuriParona & Perugia 1890, we found specimens with structures resembling “multiple vaginae”; we compared them with specimens without vaginae in terms of both morphology and molecular characterisitics (COI barcode), and found that they belonged to the same species. We also investigated the male copulatory organ (MCO) of this species, the accuracy of the original description of which is known to be a matter of debate. We found that the genital atrium is armed with 12 hooks arranged as a single circle and a central hollow stylet which is probably involved in traumatic insemina...
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Papers by Jean-Lou Justine
1. Material
A list of the parasites studied (and their hosts) is given: about 40 species of Monogeneans, 10 Digeneans, some Cestodes and Temnocephala.
2. Methods
The methods used for parasite collection, light and transmission electron microscopy are described.
Chapter II. Descriptive study of spermiogenesis and spermatozoa
1. Gross structure of the testis
The testis contains supporting cells, and germinal cells which are grouped in a common cytoplasmic mass at the spermatid stage. The evolution of this mass is described.
2. Spermiogenesis
A "classical" spermiogenesis is described in the Digeneans: 7 stages are defined. This spermiogenesis is also found in the Polyopisthocotylean Monogeneans. The various processes of spermiogenesis of other species may be compared with the "classical" spermiogenesis; they show modifications which are generally simplifications. A general Table showing the possible homologies between the stages of spermiogenesis found in the different species is proposed. In the case of the schistosome, after analysing the spermiogenesis, we suggest considering its aberrant spermatozoon as "neotenic", because it resembles a precociously matured spermatid. The fate and possible role of two organelles of the spermatid which are absent in the spermatozoon, the centre body and the striated roots, are considered. The process of separation of the nature spermatozoon is discussed. The aberrant case of the Polyopisthocotylean Monogenean Diplozoon is underlined, because it is the single case which cannot be compared with the "classical" spermiogenesis. The spermiogenesis of Monogeneans and Digeneans is compared with that of the other Platyhelminthes: it is close to that of Cestodes, but it shows fundamental differences from that of Turbellarians, in spite of a superficial resemblance of the spermatozoa.
3. Structure of the mature spermatozoa
Spermatozoa of Digeneans and Monogeneans are generally filiform. A Table compares the length of spermatozoa in various species. A "classical" pattern of spermatozoon (or type 1) is described: it comes from the "classical" spermiogenesis. The "classical" spermatozoon contains two axonemes incorporated in the sperm body and cortical longitudinal microtubules. This "classical" pattern is almost universal within Digeneans and Polyopisthocotylean Monogeneans, but is unknown in the Monopisthocotylean Monogeneans. It also exists, in a slightly modified form, in some Cestodes. Spermatozoa of the Monopisthocotylean Monogeneans are classified by means of two simple ultrastructural characteristics, the number of axonemes (1 or 2) and the presence of cortical microtubules, in three patterns (types 2, 3 and 4). The cases of the Digenean Schistosoma (non filiform) and of the Polyopisthocotylean Monogenean Diplozoon (aflagellate) are aberrant and set aside. Comparative diagrams are presented.
4. The organelles of the spermatozoon and their evolution during spermiogenesis
Centrioles of mature spermatozoa are atypical and are generally made up of 9 singlets, instead of the typical structure of triplets found in the spermatids. The axonemes show a special pattern, called 9+ ''1 "; the few variations are presented. The ornamentations associated with the membrane are described. The position of the nucleus is discussed: it is posterior, meaning that spermatozoa of Digeneans and Monogeneans are "inverted" compared with those of other animals. Coils of spermatozoa found in some species are considered to be details added to a fundamentally filiform structure.
5. Motility of spermatozoa
Comparative Tables of spermatozoan motility and ultrastructure (axonemes and microtubules) are given. It is impossible to correlate in a precise manner ultrastructure and motility.
6. Behaviour of the spermatozoa during fertilization
The spermatozoa penetrate the oocyte with the nucleus in a posterior position; available data concern only few species, mainly with "classical" spermatozoa.
7. Partial conclusion after chapter II
Data advanced in this chapter are summarised and discussed.
Chapter III. Morphology of spermatozoa, biology of fertilization and phylogeny
1. Introduction
Some classical cases of the literature are considered.
2. Spermatozoa and biology of fertilization
The "classical" spermatozoon (type 1 ) of the Digeneans and Polyopisthocotylean Monogeneans seems to be linked with internal fertilization, through genital ducts (Digeneans) or by hypodermic injection (at least a part of the Polyopisthocotylean Monogeneans). In the monopisthocotylean Monogeneans (with spermatozoa of types 2, 3 and 4), the literature mentions some cases of spermatophores, but it is not possible to establish a strict relationship between these sperm structures and fertilization by spermatophore. The case of the Polyopisthocotylean Monogenean Diplozoon is interesting. In this animal, the biology of fertilization is unique because the two members of the pair are fused, and the spermatozoon is the only aflagellate case known: it displays a remarkable correlation between the biology of fertilization and sperm structure. The case of the schistosomes is discussed. Attempts are made to relate the atypical structure of the spermatozoon to the peculiar characteristics of the schistosomes: gonochorism, progenesis, life in pairs. It seems that life in permanent pairs is a factor of differentiation of atypical sperm structures, in the schistosomes, Diplozoon, and some Didymozoonidae.
3. Spermatozoa and phylogeny
Relationships between phylogeny, taxonomy, biology of fertilization and sperm structure are discussed. In the Trematodes (Digeneans and Aspidogastreans), the sperm structure is very homogenous (type 1) and thus of little use for the understanding of phylogeny within this group. The few variations known (Didymozoata and Strigeata) seem to be linked mainly with the biology of fertilization rather than with phylogeny. In the Monogeneans, comparative spermatology allows us to separate Polyopisthocotyleans and Monopisthocotyleans. Polyopisthocotylean Monogeneans are very homogenous and share type 1 with the Trematodes. The single really different case, Diplozoon, seems to have no phyletic value but is correlated with the biology of fertilization. Monopisthocotylean Monogeneans show three types of spermatozoa. A phyletic scheme built only from sperm ultrastructure shows resemblances with classical phylogenies drawn from the structure of the adults, and a remarkable coincidence with modern phylogenies elaborated from the structure of larvae. The case of the Monogeneans is thus a demonstrative example of the usefulness of comparative spermatology for the understanding of phylogeny.
4. Trends in the evolution of spermatozoa in parasitic Platyhelminthes
Spermatozoa of Platyhelminthes are generally biflagellate. After a comparative study, we consider that the less evolved spermatozoon in the parasitic Platyhelminthes (Monogeneans, Digeneans and Cestodes) is the "classical" type, or type 1. This type 1 is maintained in the Digeneans and Polyopisthocotylean Monogeneans, but is modified in the Cestodes (loss of the mitochondrion, and of one axoneme in some cases), and in the Monopisthocotylean Monogeneans (loss of the microtubules am of one axoneme). The origin of type 1 may possibly be found in the Turbellaria Rhabdocoela Kalyptorhynchia. Comparative and phyletic diagrams of sperm structure in the phylum Platyhelminthes are given.
L’attention des lecteurs est attirée sur le fait que cet article date de 2001.
Le poster présente ici trois exemples de suivis d’espèces invasives via l’utilisation des sciences participatives. D’une manière générale, ces programmes permettent de suivre des espèces (via des inventaires naturalistes, de la cartographie etc.) dans un but de connaissance et de conservation de la biodiversité, associant différents observateurs (naturalistes, grand public) et des organismes scientifiques. Un maximum d’observations est alors collecté facilement et rapidement de manière pédagogique et ludique.
Les sciences participatives sont particulièrement efficaces pour détecter précocement des espèces invasives. C’est le cas du Plathelminthe de Nouvelle Guinée, Platydemus manokwari de Beauchamp, 1963, découvert récemment dans les serres du Jardin des Plantes de Caen et actuellement confiné. Elles permettent également de suivre des taxons à large distribution comme le Frelon asiatique, Vespa velutina Lepeletier, 1836 ou le plathelminthe dit « marron plat ».
L’engouement des différents contributeurs pour ces sciences participatives permet d’enrichir les connaissances sur la distribution des espèces, leur écologie et leur biologie, et de définir des actions appropriées dans le but de limiter la perte de biodiversité.