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Revista Peruana de Biología

On-line version ISSN 1727-9933

Rev. peru biol. vol.27 no.2 Lima Apr-Jun 2020

http://dx.doi.org/10.15381/rpb.v27i2.16458 

Trabajos originales

Nueva especie de Neoparasitylenchus (Tylenchida, Allantonematidae), parasitando a Harmonia axyridis (Coleoptera, Coccinellidae) en Argentina

New specie of Neoparasitylenchus (Tylenchida, Allantonematidae), parasitizing Harmonia axyridis (Coleoptera, Coccinellidae) from Argentina

Nora B. Camino*  4  , Investigador CIC
http://orcid.org/0000-0003-4910-3986

Guillermo R. Reboredo3  4  a 
http://orcid.org/0000-0002-1214-316X

Sandra E. González4  b  , Personal de Apoyo CIC

3 CONICET

4 Centro de Estudio Parasitológicos y de Vectores, CEPAVE CCT La Plata CONICET, Facultad de Ciencias Naturales y Museo, UNLP. Boulevard 120 y 62, 1900 La Plata, Argentina.

Resumen

Se cita por primera vez el género Neoparasitylenchus Nickle, 1967 (Tylenchida, Allantonematidae), parásito de Harmonia axyridis (Pallas, 1773) (Coleoptera, Coccinellidae) para Argentina. Se describe la especie nueva Neoparasitylenchus platense sp. n. que se caracteriza por tener en las formas de vida libre la región labial rodeada de una estructura plana, estilete delgado, levemente curvado, apéndice caudal redondeado, hembras con cuerpo marrón claro, estilete no hundido en el cuerpo y no prominente, vulva y ano subterminal, apéndice caudal redondeado, con una proyección en forma de clavija, ovíparos. Los machos con un estilete y un esófago parcialmente degenerados, espículas filiformes con base ensanchada, gubernaculum corto, bursa leptodera.

Palabras claves: nemátodos; Neoparasitylenchus; Coccinellidae; taxonomía

Abstract

Presence of the genus Neoparasitylenchus Nickle, 1967 (Tylenchida, Allantonematidae), parasitizing Harmonia axyridis (Pallas, 1773) (Coleoptera, Coccinellidae) in Argentina. We describe a new species Neoparasitylenchus platense sp. n., which is characterized by having the free living stages lip region flatly rounded, spear slender, faintly knobbed, tail rounded, females with light brown body, stylet not sunken into body, and not prominent, subterminal vulva and anus, obtusely rounded tail end, with a peg-like projection, oviparous, and the males with a little stylet and partially degenerate oesophagus, spicules filiform with widened base, short gubernaculum, leptodera bursa.

Keywords: nematodes; Neoparasitylenchus; Coccinellidae; taxonomy

Introduction

The genus Neoparasitylenchus was erected by Nickle in 1967. The type species N. cryphali was described by Fuchs in 1914 and placed in the genus Tylenchus, as T. cryphali. In 1922 Micoletzky located this species naming it Parasitylenchus dispar var. cryphali. Later, Filipjev (1934) put this species as Aphelenchys cryphali; meanwhile Schneider (1939) and Rühm (1956) accepted this species as Parasitylenchus dispar var. cryphali. Nickle (1967) conducted a study organizing the generic nomenclature of Tylenchida nematodes. At this moment 24 species have been described from the genus Neoparasitylenchus, within which only five were described as having free-living stages: N. amvlocercus Poinar & Caylor, 1974, N. cinerei (Fuchs, 1929) Nickle, 1967, N. cryphali (Fuchs, 1914) Nickle, 1967, N. hylastis (Wülker, 1923) Nickle, 1967, and N. pessoni (Fuchs, 1914) Nickle, 1967; all parasites of curcullionid hosts. In this paper we describe another species of the genus Neoparasitylenchus, N. platense sp. n., a parasite of Harmonia axyridis (Pallas, 1773) (Coleoptera, Coccinellidae) Harmonia axyridis Pallas, 1773, the multicoloured Asian lady beetle (Koch, 2003), which is introduced as a biological control agent that was rapidly spread all over Argentina (Saini, 2004). Despite the fact that they are an effective biological control agent in agricultural and landscape environments, they have become a major nuisance to homeowners because of their habit of invading houses and buildings in large numbers while searching for protected sites to overwinter in the fall (mid-May to early August) and appearing again on warm days in September and October (Saini, 2004). In addition, beetles may get in picnic food and drinks, "swarm" like bees and land on people (Brown, 2011). This species prey upon many species of injurious soft-bodied insects such as aphids, scales, and psyllids and it is thus considered beneficial for growers and agriculturalists. Ladybird is the name that has been used for more than six centuries in Europe for this coleopteran species.

Material and methods

Insects: adult coccinellid insects were collected by hand from September 2016 to April 2017 on plant species Cucurbita maxima var. zapallito (Carrière) Millán, 1947 (round green zucchini), at a locality near Gran La Plata, Colonia Urquiza (34°96'72”S, 58°04’96”W). The beetles were distributed in individual plastic containers. In total, 260 adults of Harmonia axyridis (Pallas, 1773) (Coleopera, Coccinellidae), were sampled and dissected. The coccinellids adults were dissected in Petri dishes filled with distilled water under a stereomicroscope. Nematodes: living nematodes were removed from the hemocel of adult host, and then they were killed by placing them in distilled water at 60 °C for 2 minutes. They were fixed in 50% TAF solution in water for 48 hours and then into pure TAF (Poinar 1975). All the specimens were used for photographing in Olympus BX51 microscope with Olympus DP71 camera. Measurements of common nematode body features were performed on 16 fixed nematode specimens of each nematode stage of life cycle. Mean and in parenthesis minimum and maximum.

Results

(Follow Siddiqi 2000)

Order Tylenchida Thorne, 1949

Suborder Hexatylina Siddiqi, 1980

Superfamily Sphaerularioidea Lubbock, 1861

Family Allantonematidae Pereira, 1931

Subfamily Allantonematinae Pereira, 1931

Genus NeoparasitylenchusNickle, 1967

Neoparasitylenchus platense sp. n.

(Figures 1 - 8)

Figures 1 7: Neoparasitylenchus platense sp. n. 1. Entomoparsitic female, 2. Entomoparasitic head female, 3. Entomoparasitic tail appendage female, 4. Posterior end of male, 5. Larva, 6. Free living female, 7. Free living head female. Bars= 1: 200 µm, 2, 3, 4, 5, 7: 50 µm, 6: 100 µm. 

Figure 8: Life cycle of Neoparasitylenchus platense sp. n. 

Description: Entomoparasitic female (n= 18): body worm-shaped, usually curved (Fig. 1). Cephalic region overgrown by body enlargement (Fig. 2). Light brown body. Stylet not sunken into body, and not prominent. Subterminal vulva and anus. Obtusely rounded tail end, with a peg-like projection (Fig. 3). Oviparous. Body length: 2,004 µm (1,655 - 2,100) ; width at midbody: 70 µm (68 - 82) ; length of stylet: 3,5 µm (3 - 4) ; head to excretory pore: 176.30 µm (168.42 - 180.25); head to nerve ring: 96.55 µm (72.50 - 122.32); tail length: 10.35 µm (10 - 11.50) ; length vulva to tail tip: 130 µm (124 - 145); length anus to tail tip: 50 µm (42 - 64)

Male (n= 16) (Fig. 4): little stylet and oesophagus partially degenerate, spicules filiform with widened base, short gubernaculum, leptodera bursa. Body length: 1,242 µm (1,200 - 1,320) ; width at midbody: 36 µm (24 - 47.55); head to excretory pore: 92 µm (90 - 120); head to nerve ring: 50 µm (45.50 - 56) ; tail length: 11 µm (10 - 12); spicules length: 15.50 µm (15 - 17); spicules width: 0.72 µm (0.7 - 0.8); gubernaculum length: 7 µm (6 - 7.5); length of leptodera bursa: 35 µm (32 - 38). The entomoparasitic and free living males are similar in morphometric data.

First stage larvae (n= 25) (Fig. 5): lip region flatly rounded, spear slender, faintly knobbed, oesophagus a narrow tube, with a broad nerve ring. Rounded tail.

Partially free-living females (n= 12): body vermiform (Fig. 6), cephalic region with a cap (Fig. 7), stylet with slight basal thickenings, dorsal gland opened near of stylet base, excretory pore posterior to nerve ring, vulva at about 90 % of body length, immature ovary but with some cells, conoid pointed and rounded tail. This female fertilized invades host´s larva. Body length: 1,080 µm (1,000 - 1,200); width at midbody: 68 µm (60 - 82); length of stylet: 2 µm (2 - 2.2); head to excretory pore: 213 µm (190 - 225); head to nerve ring: 154 µm (145 - 168); tail length: 8 µm (7 - 8.5); length vulva to tail tip: 126 µm (120 - 134); length anus to tail tip: 54 µm (52 - 62).

Type host: Indifferent parasitism in adult males and females of Harmonia axyridis (Pallas, 1773) (Coleoptera, Coccinellidae).

Type locality: Colonia Urquiza (34°96'72”S, 58°04’96”W), Gran La Plata, Buenos Aires, Argentina

Type material: Holotype and allotype deposited in Museo de La Plata, and paratypes deposited in Helminthological Collection of CEPAVE

Effects on the host: this parasite reduces the fat body and atrophies the gonads, sterilizing and then killing it.

Discussion

While conducting field surveys on horticultural pests in the horticultural belt, we found Harmonia axyridis parasitized by (Camino et al. 2016) Metaparasitylenchus Wachek, 1955 (Nickle, 1967), SulphuretylenchusRühm, 1956 (Nickle, 1967), Contortylenchus Rühm, 1956, and Camino et al. (2019) described a new species Parasitylenchus pseudobifurcatus. Now we found another genus and new species Neoparasitylenchus platense sp. n. There are only five species of the genus Neoparasitylenchus that we can compare with our new species since they are the only ones that described the free-living stages, but they can be separated as follow: Neoparasitylenchus amvlocercus the females with rounded tail, distinct mouth cone, stylet with faint or no thickenings, position of the vulva and lack of a crown-shaped lip region. Neoparasitylenchus cinerei has a pointed tail in free living female, the cone mouth in the parasitic female. Neoparasitylenchus cryphali presents a well-developed male stylet and a broad wide bursa. Neoparasitylenchus hylastis has basal swellings on the stylet leptodera bursa, and Neoparasitylenchus pessoni the adult parasitic female has a mouth cone and a pointed tail.

Neoparasitylenchus platense sp. n. is diagnosed by having the free living stages lip region flatly rounded, spear slender, faintly knobbed, rounded tail, females with light brown body, stylet not sunken into body, and not prominent, subterminal vulva and ano, obtusely rounded tail end, with a peg-like projection, oviparous, and the males with a little stylet and partially degenerate oesophagus, spicules filiform with widened base, short gubernaculum, leptodera bursa.

Life cycle of Neoparasitylenchus platense sp. n. (Fig. 8)

After mating, the free-living female enters an immature coccinelid H. axyridis (last larval instar or pupa), and remains in the adult stage where it is located in the body cavity and begins to parasitize the host. Larvae are born and transformed into entomoparasitic females and males, copulate and then larvae that reach in stage III leave the host. They suffer two molts in the environment. The free living females and males appear and the free-living males mate and the cycle is restarted.

Agradecimientos / Acknowledgments:

We would like to thank to Lic. Luis Giambelluca for photograpied the material. Many thanks are expressed to Manuela Reboredo for her careful review of the English language.

Literature cited

Brown MW. 2011. Importance of early arrival of adult Harmonia axyridis for control of Aphids spiraecola on apple. BioControl 56: 65-69. 10.1007/s10526-010-9311-0 [ Links ]

Camino NB, González SE, Reboredo GR, Rosales MN, Zanca FM. 2016. Tylenchids nematodes (Tylenchida) parasitizing field population of Harmonia axyridis Pallas, and Cycloneda sanguinea (Linnaeus) (Coleoptera, Coccinellidae) in Argentina. Revista peruana de biología 23(3):325-328. 10.15381/rpb.v23i3.12870 [ Links ]

Camino NB, Rodríguez Gil S, Reboredo GR, González SE. 2019. Morphological and cytogenetic description of a new species of Parasitylenchus Micoletzky, 1922 (Tylenchida, Allantonematidae) parasitizing Harmonia axyridis (Pallas, 1773) (Coleopera, Coccinellidae) in Argentina. Revista peruana de biología 26(1): 027 - 032. 10.15381/rpb.v26i1.15907 [ Links ]

Filipjev IA. 1934. The classification of the free-living nematodes and their relations to the parasitic nematodes. Smithsonian miscellaneous collections, 89, 63 p. [ Links ]

Fuchs G. 1914. Über Parasiten und andere biologisch an die Borkenkäfer gebundene Nematoden. Vershandl Gasellsch. Deutscher Naturforscher und Ärzte. 2: 689-692 [ Links ]

Fuchs G. 1929. Die Parasiten einiger Rüssel-und Borkenkafer. Zeitschrift für Parasitenkunde 2: 248-285 [ Links ]

Koch RL. 2003. The multicolored Asian lady beetle, Harmonia axyridis: A review of its biology, uses in biological control, and non-target impacts. Journal of Insect Science. 3: 32. 10.1093/jis/3.1.32 [ Links ]

Micoletzky H. 1922. Die freilebenden Erd-Nematoden. Archiv Naturgeschichte Abteilung A. 87: 1-650 [ Links ]

Nickle WR. 1967. On the classification of the insect parasitic nematodes of the Sphaerilariidae Lubbock, 1861 (Tylencoidea: Nematoda). Procceding of the Helminthological Society of Washington. 34: 72-94 [ Links ]

Poinar GO Jr., Caylor JN. 1974. Neoparasitylenchus amvlocercus sp.n. (Tylenchida: Nematodea) from Conophthorus monophyllae (Scolytidae: Coeloptera) in California with a synopsis of the Nematode genera found in bark beetles. Journal of Invertebrate Pathology, 24:112-119 [ Links ]

Rühm W. 1956. Die Nematoden der Ipiden. Parasitologische Scriftenreihe, 6, 437 p. [ Links ]

Saini ED. 2004. Presencia de Harmonia axyridis (Pallas) (Coleoptera: Coccinelidae) en la Provincia de Buenos Aires. Aspectos biológicos y morfológicos. Ria, Inta, Argentina. 33: 151-160. [ Links ]

Schneider W. 1939. Würmer oder Vermes. II Fadenwürmer oder Nematoden. I Freilebende und pflanzenparasitische Nematoden. Tierwelt Deutschlands, 36: 1.260 [ Links ]

Siddiqi MR. 2000. Tylenchida. Parasites of plants and Insects. 2nd Edition. CABI Publishing, Wallingford UK. 848 pp, ISBN 085199-202-1. [ Links ]

Wülker G. 1923. Uber Fortpflanzung und Entwicklung von Allantonema und verwandten Nematoden. Ergebnisse und Fortschritte der Zoologie, 5: 389-507 [ Links ]

Fuentes de financiamiento / Funding: The present work was carried out thanks to the financing of the Comisión de Investigaciones Científicas de la provincia de Buenos Aires, CIC and of the funds of the Incentive Program of the Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata (UNLP).

Aspectos éticos / legales; Ethics / legals: This work did not incur any ethical or legal problems.

Publicación registrada en Zoobank/ZooBank article registered: LSIDurn:lsid:zoobank.org:pub:FBE9DC98-04C4-4074-9037-1F5979320E2F

Acto nomenclatural/nomenclatural act: Neoparasitylenchus platense Camino, Reboredo & González, 2020 LSIDurn:lsid:zoobank.org:act:B1146E52-46CC-40D0-B9FA-6627EA3B53E7

Received: July 15, 2019; Accepted: February 16, 2020

a grreboredo@yahoo.com.ar

b san.gonzalez.san@gmail.com

*Corresponding author:nemainst@cepave.edu.ar

Conflicto de intereses / Competing interests: The authors declare no conflict of interest.

Rol de los autores / Authors Roles: NBC, GRR, SEG: conducted the sampling, processed the material in the laboratory; NBC: wrote the manuscript; NBC, GRR,SRG: revised and approved the manuscript.

Creative Commons License Este es un artículo publicado en acceso abierto bajo una licencia Creative Commons