TRABAJOS CIENTÍFICOS
Egg parasitoids of Megamelus spp. (Hemiptera: Delphacidae) in Argentina tentativa
Parasitoides oófagos de Megamelus spp. (Hemiptera: Delphacidae) en la Argentina
Triapitsyn, Serguei V.*, Alejandro J. Sosa** and M. Cristina Hernández**
* Entomology Research Museum, Department of Entomology, University of California,
Riverside, California, 92521, USA; e-mail: serguei.triapitsyn@ucr.edu
** USDA-ARS South American Biological Control Laboratory, General Simón Bolívar 1559
(B1686), Hurlingham, Buenos Aires, Argentina: e-mail: alejsosa@speedy.com.ar, crisher@speedy.com.ar
ABSTRACT. Egg parasitoids (Hymenoptera: Eulophidae, Mymaridae, and Platygastridae) of Megamelus spp. (Hemiptera: Delphacidae) in Argentina are reviewed and keyed. Four new species are described: Anagrus (Anagrus) empanadus Triapitsyn, sp. nov. (Mymaridae, parasitoid of M. scutellaris Berg feeding on water hyacinth, Eichhornia crassipes (Martius) Solms-Laubach, Aprostocetus (Ootetrastichus) riverplaticus Triapitsyn, sp. nov. (Eulophidae: Tetrastichinae, parasitoid of M. bellicus Marino de Remes Lenicov & Sosa), A. (Ootetrastichus) yerbamatei Triapitsyn, sp. nov. (parasitoid of M. bellicus, M. scutellaris and Megamelus sp.), all from Buenos Aires Province (A. (Ootetrastichus) yerbamatei also occurs in Formosa Province), and Parascelio sabcli Triapitsyn, sp. nov. (Platygastridae: Scelioninae, parasitoid of M. scutellaris in Formosa, the host association is tentative). Other known egg parasitoids of Megamelus spp. in Argentina include Kalopolynema (Kalopolynema) poema Triapitsyn & Berezovskiy (Mymaridae, parasitoid of M. scutellaris in Buenos Aires), and also Cremastobaeus atratus Loiácono & Mulvani (Platygastridae: Scelioninae, parasitoid of M. scutellaris in Formosa, the host association is tentative).
KEY WORDS. Delphacidae; Megamelus; Eulophidae; Mymaridae; Platygastridae.
RESUMEN. Se revisaron los parasitoides oófagos (Hymenoptera: Eulophidae, Mymaridae, y Platygastridae) de Megamelus spp. (Hemiptera: Delphacidae) de la Argentina, y se presenta una clave para su identificación. Se describen cuatro especies nuevas: Anagrus (Anagrus) empanadus Triapitsyn, sp. nov. (Mymaridae, parasitoide de M. scutellaris Berg que se alimenta de camalote, Eichhornia crassipes (Martius) Solms-Laubach; Aprostocetus (Ootetrastichus) riverplaticus Triapitsyn, sp. nov. (Eulophidae: Tetrastichinae, parasitoide de M. bellicus Marino de Remes Lenicov & Sosa); A. (Ootetrastichus) yerbamatei Triapitsyn, sp. nov. (parasitoide de M. bellicus, M. scutellaris y Megamelus sp.), todos de la provincia de Buenos Aires (A. (Ootetrastichus) yerbamatei también se encuentra en Formosa); y Parascelio sabcli Triapitsyn, sp. nov. (Platygastridae: Scelioninae, parasitoide de M. scutellaris en Formosa, la asociación con el huésped es tentativa). Se incluyen otros parasitoides oófagos conocidos de Megamelus spp. en la Argentina, tales como Kalopolynema (Kalopolynema) poema Triapitsyn & Berezovskiy (Mymaridae, parasitoide de M. scutellaris en Buenos Aires) y también Cremastobaeus atratus Loiácono & Mulvani (Platygastridae: Scelioninae, parasitoide de M. scutellaris en Formosa, la asociación con el huésped es tentativa).
PALABRAS CLAVE. Delphacidae; Megamelus; Eulophidae; Mymaridae; Platygastridae.
Recibido: 14-XII-2009;
Aceptado: 8-VII-2010
INTRODUCTION
Five species of the planthopper genus
Megamelus Fieber (Hemiptera: Delphacidae)
are known from South America, these were
recently reviewed by Sosa et al. (2007b). They
are frequently associated with aquatic plants,
particularly the Pontederiaceae. Megamelus scutellaris Berg is considered a candidate
for biocontrol of water hyacinth, Eichhornia
crassipes (Martius) Solms-Laubach, an
invasive aquatic weed that clogs waterways,
lakes, and channels in several countries
beyond its native range (Sosa et al., 2004,
2005, 2007a, 2007b).
There are few records of egg parasitoids
of Megamelus spp. in South America:
Kalopolynema (Kalopolynema) poema
Triapitsyn & Berezovskiy (Mymaridae) was
reported from eggs of M. scutellaris on
water hyacinth (Triapitsyn & Berezovskiy,
2002; Sosa et al., 2004, 2005), and
Aprostocetus (Ootetrastichus) sp. from eggs
of M. bellicus Marino de Remes Lenicov & Sosa (Mariani et al., 2007; Sosa et al.,
2007b), both in Buenos Aires Province,
Argentina. The latter is described here as
A. (Ootetrastichus) riverplaticus Triapitsyn,
sp. nov. Extralimital records include
Kalopolynema (Kalopolynema) ema (Schauff & Grissell) in Florida (USA) on M. davisi Van
Duzee (Triapitsyn & Berezovskiy, 2002), and
Anagrus incarnatus Haliday (Mymaridae) in
Wales (UK) on Megamelus notulus (Germar)
(Whalley, 1956).
Megamelus scutellaris has been recently
approved for release in Florida, thus a study
of its egg parasitoid fauna in the native range
was a necessity. In the course of this study,
a number of both internal and internal/external egg parasitoids from three families of
Hymenoptera (Eulophidae, Mymaridae, and
Platygastridae) were discovered in Argentina,
and these are keyed and reviewed herein.
MATERIAL AND METHODS
Most of the specimens were reared from
the delphacid (Megamelus spp.) eggs, stored
in ethanol, then dried using a critical point
drier and point-mounted; selected specimens
were dissected and slide-mounted in Canada
balsam. The collections from Formosa
Province were made by incubating (in the
laboratory) the petioles of water hyacinth in
opaque bottles with a translucent vial in the
cap; the emerging parasitoids (if any) were
collected daily.
Terms for morphological features follow
Gibson (1997); we also use the abbreviation
F for an antennal funicle (or flagellar in males
of Mymaridae) segment. Unless indicated
otherwise, measurements are given in
micrometers (µm) as length or, where
appropriate (e.g. for the wings), as length:
width ratios.
Abbreviations for depositories of
specimens are as follows: CNCI, Canadian
National Collection of Insects, Ottawa,
Ontario, Canada; MLPA, Museo de La Plata,
La Plata, Buenos Aires, Argentina; UCRC,
Entomology Research Museum, University
of California, Riverside, California, USA;
USNM, National Museum of Natural History,
Washington, DC, USA.
The first author is solely responsible for
most of the text; the second and the third
authors provided the reared material for this
study and contributed to the introduction
and description of the collecting methods.
RESULTS
Taxonomy
Key to egg parasitoids of Megamelus spp. in Argentina
1. Forewing with venation short, extending at
most to about 0.3x length of wing ............................................................................... 2
1´. Forewing with venation longer,
extending at least to about 0.5x length of
wing ........................................................ 3
2. Forewing at least 9.8x as long as wide,
with only one, median, row of setae on
disc (Fig. 21) ............................. Anagrus (Anagrus) empanadus Triapitsyn, sp. nov.
2´. Forewing about 7.3x as long as wide, with
disc densely setose beyond venation (Fig.
25) ............ Kalopolynema (Kalopolynema)
poema Triapitsyn & Berezovskiy
3. Antenna (excluding 3 or 4 anelli) 7- or
9-segmented; body smooth .....................4
3´. Antenna 12-segmented (anelli absent,
F1 and F2 may be almost fused); body with
reticulate sculpture ............................. 7
4. Antenna (excluding 4 anelli) 7-segmented,
with scape not expanded (female) ...................................................................5
4´. Antenna (excluding 3 anelli)
9-segmented, with scape notably expanded
(male) ...................................................... 6
5. Head mostly brown; midlobe of
mesoscutum with 1 pair of setae............... Aprostocetus (Ootetrastichus)
riverplaticus Triapitsyn, sp. nov.
5´. Head mostly yellow and light brown;
midlobe of mesoscutum with 2 pairs of setae.................... Aprostocetus (Ootetrastichus)
yerbamatei Triapitsyn, sp. nov.
6. Scape about 2.0x as long as wide....................................... Aprostocetus
(Ootetrastichus) riverplaticus Triapitsyn, sp. nov.
6´ Scape about 2.9x as long as wide......................... Aprostocetus (Ootetrastichus)
yerbamatei Triapitsyn, sp. nov.
7. Forewing with postmarginal vein
present and longer than stigmal vein
(Fig. 28) [female antenna with F1 and F2
almost fused and clava 4-segmented (Fig.
26)].................................................
Cremastobaeus atratus Loiácono & Mulvani
7´. Forewing with postmarginal vein absent
(Fig. 32) [female antenna with F1 and F2 not
fused and clava 5-segmented (Fig. 30)] ................. Parascelio sabcli Triapitsyn, sp. nov.
Eulophidae: Tetrastichinae
Aprostocetus (Ootetrastichus) riverplaticus Triapitsyn, sp. nov. (Figs 1-7)
Figs. 1-4. Aprostocetus (Ootetrastichus) riverplaticus sp. nov., female (holotype): 1, antenna; 2,
mesosoma; 3, metasoma; 4, forewing.
Figs. 5-7. Aprostocetus (Ootetrastichus) riverplaticus sp. nov., male (paratype): 5, antenna; 6, genitalia;
7, forewing.
Aprostocetus (Ootetrastichus) sp.: Mariani et al., 2007: 189-190, 195 (information on the host and egg parasitism); Sosa et al., 2007b: 801, 803 (host information, biology).
Description. Female (holotype and
paratypes). Body length 1650-2245 µm
(dry-mounted paratypes). Head mostly
brown except eyes and ocelli dirty pink;
mesonotum greenish with bright metallic
sheen, mesopleura mostly shining brown,
tegula bright yellow; two basal gastral
segments mostly yellow, remainder of gaster
brown; scape, sometimes pedicel partially,
and anelli yellowish, remainder of antennal
segments a little darker (light brown); legs
mostly yellow or yellowish brown except
metacoxa shining brown and all apical
tarsomeres brown.
Antenna (Fig. 1) with scape minus short
radicle about 4.6x as long as wide and
almost smooth; funicle (excluding 4 anelli,
second anellus very short) 3-segmented, F1
the longest funicle segment, slightly longer
than pedicel, F2 about as long as F3; clava
2-segmented, apical claval segment with a
spicula and about 1.8x length of basal claval
segment; funicle and claval segments with
long hairs and each with at least 2 hair-like
longitudinal sensilla. Mesosoma (Fig. 2) with pronotum
entire, with more or less conspicuous
sculpture; mesoscutum and scutellum faintly
longitudinally striate, midlobe of mesoscutum
with 1 pair of setae, scutellum with 2 pairs
of setae, scutellar placoid sensilla about in
the middle of scutellum. Metanotum and
propodeum with inconspicuous sculpture,
almost smooth.
Wings. Forewing (Fig. 4) 3.3-3.4x as
long as wide; venation extending to about
0.6x length of wing, disc almost hyaline,
mostly bare behind base of submarginal vein
and densely setose elsewhere; the longest
marginal seta 0.23-0.32x greatest width of
disc. Hind wing 10.4-10.8x as long as wide;
disc hyaline, bare behind base of venation
and densely setose elsewhere; the longest
marginal seta 1.2-1.4x greatest width of
disc.
Metasoma (Fig. 3) with gaster elongate
(particularly the apical gastral tergum),
notably longer than mesosoma. Ovipositor
occupying almost entire length of gaster, a
little exserted beyond gastral apex; ovipositor
length: metatibia length ratio 2.9-3.1:1.
Measurements (µm) of the holotype.
Body: 1906; head: 271; mesosoma: 492;
gaster: 1156; ovipositor: 1057. Antenna:
scape: 155; pedicel: 74; F1: 79; F2: 67; F3:
67; clava: 157. Forewing: 1236:366; longest
marginal seta: 118. Hind wing: 1045:97; longest marginal seta: 136.
Male (paratypes). Body length 1024-1321 µm (dry-mounted paratypes). Similar
to female except for the normal sexually
dimorphic features such as color, antenna,
and genitalia, as follows. Head mostly yellow
except eyes and ocelli dirty pink and area
between posterior ocelli brown; pronotum
brown dorsally, rest of metanotum shining
brown with greenish metallic tinge; basal
gastral segments yellow, apical segments
brown; scape yellow to light brown, pedicel
and anelli light brown, remainder of antennal
segments slightly darker (brownish); legs
mostly yellow except all apical tarsomeres
brown. Antenna (Fig. 5) with scape about 2.0x
as long as wide; funicle (excluding 3 anelli)
4-segmented, F1-F4 more or less subequal in
length; clava 3-segmented, apical segment
with a spicula; funicle and claval segments
with long hairs and each with at least 2 hairlike
longitudinal sensilla. Forewing (Fig.
7) about 3.2x as long as wide, the longest
marginal seta about 0.27x greatest forewing
width; hind wing about 9.4x as long as wide;
discs of forewing and hind wing hyaline.
Genitalia (Fig. 6) typical for the subgenus,
digitus with a spine.
Diagnosis. In addition to the characters
mentioned in the keys above and below,
female of A. (Ootetrastichus) riverplaticus sp. nov. differs from that of A. (Ootetrastichus)
yerbamatei sp. nov. in having a relatively
wider forewing (3.3-3.4x as long as wide) with
relatively shorter marginal setae (the longest
marginal seta is 0.23-0.32x greatest width
of the disc) whereas in A. (Ootetrastichus)
yerbamatei the female forewing is 3.6-3.8x
as long as wide and the longest marginal seta
is 0.4-0.5x greatest width of the disc. The
male of (Ootetrastichus) riverplaticus differs
from that of A. (Ootetrastichus) yerbamatei in also having a relatively wider forewing
(about 3.2x as long as wide) with relatively
shorter marginal setae (the longest marginal
seta is about 0.27x greatest width of the disc)
whereas in A. (Ootetrastichus) yerbamatei the male forewing is about 4.0x as long as
wide and the longest marginal seta is about
0.5x greatest width of the disc.
The females of A. (Ootetrastichus)
riverplaticus and A. (Ootetrastichus)
yerbamatei differ from that of A.
(Ootetrastichus) infulatus (De Santis), the
only species of the subgenus Ootetrastichus Perkins of the genus Aprostocetus Westwood
that was previously described from Argentina
(De Santis, 1957), in having the antennal
flagellum with 4 anelli and a relatively longer
ovipositor, as indicated in the key below.
In A. (Ootetrastichus) infulatus, flagellum
of the female antenna (Fig. 15) has 3 anelli
(Luft Albarracin & Triapitsyn, 2007) and the
ovipositor (Fig. 16) is notably shorter (the
ovipositor length:metatibia length ratio is
1.5:1 in the holotype). The longest marginal
seta on the forewing (Fig. 17) of the holotype
female of A. (Ootetrastichus) infulatus is
0.27-0.28x maximum forewing width.
Figs. 15-17. Aprostocetus (Ootetrastichus) infulatus (De Santis), female (holotype): 15, antenna; 16,
mesosoma and metasoma; 17, forewing.
The only other two species of the subgenus A. (Ootetrastichus) registered for the Neotropical region are the little known A. (Ootetrastichus) coxalis (Howard) (Grenada) and A. (Ootetrastichus) cupreus (Ashmead) (Grenada and Saint Vincent and the Grenadines) (Ashmead, 1894; Howard, 1897; De Santis, 1979; LaSalle & Schauff, 1992). Female head and mesosoma are mostly dark brown dorsally with a dark green metallic sheen in A. (Ootetrastichus) cupreus, and its apical gastral tergum is notably less elongate than in A. (Ootetrastichus) riverplaticus or A. (Ootetrastichus) yerbamatei. Because identification of the Neotropical species of A. (Ootetrastichus) is currently very problematic (prior to this study there were no keys available to separate them), a partial key is provided here (A. (Ootetrastichus) coxalis is excluded because the original description of its holotype, which was not available to us, is poor).
Key to the Neotropical species of Aprostocetus (Ootetrastichus) (females)
1. Ovipositor length:metatibia length ratio
about 1.5:1 .................................................................A. (O.) infulatus (De Santis)
1´. Ovipositor length:metatibia length ratio
at least 1.8:1 .....................................2
2. Head mostly brown or dark brown with
or without dark green metallic sheen .................................................................... 3
2´. Head mostly yellow and light brown
......... A. (O.) yerbamatei Triapitsyn, sp. nov.
3. Gaster with two basal terga mostly yellow
................................................................
A. (O.) riverplaticus Triapitsyn, sp. nov.
3´. Gaster with two basal terga brown .................................... A. (O.) cupreus (Ashmead)
Etymology. The species is named after La Plata River (Río de la Plata, sometimes rendered River Plate in British English) in which basin it occurs.
Host. Megamelus bellicus Remes Lenicov & Sosa. Mariani et al. (2007) reported a 25.1% egg parasitism of this host in Argentina by A. (Ootetrastichus) riverplaticus [as Aprostocetus (Ootetrastichus) sp.], which is an internal/external egg parasitoid: the eulophid larvae develop within the host's egg and once emerged, they consume the other eggs in the scar (Sosa et al., 2007b), i.e. acting as egg predators. Its possible ability to attack also eggs of M. scutellaris Berg has yet to be demonstrated.
Type material. Holotype female [MLPA] on slide labeled: "ARGENTINA: Buenos Aires, Hurlingham, USDA-ARS South American Biol. Control Lab., 20.v.2005, A. Sosa & J. Dorado. Egg predator of Megamelus sp. (bellicus ms name of A. Sosa) colony on Pontederia cordata. Mounted at UCR/ERM by V. V. Berezovskiy 2005 in Canada balsam". Paratypes: ARGENTINA, Buenos Aires: Hurlingham, USDA-ARS South American Biological Control Laboratory: 22.i.2003, S. V. Triapitsyn, M. C. Hernández (from eggs of Megamelus sp. [later described as M. bellicus Remes Lenicov & Sosa (Sosa et al., 2007b)] on water hyacinth) [2 females, 4 males on points, UCRC]; 23.i.2003, M. C. Hernández, S. V. Triapitsyn (yellow pan traps in an artificial pond with water hyacinth infested with colonies of Megamelus scutellaris Berg and Megamelus sp. (later described as M. bellicus) [8 females, 3 males on points, UCRC, 1 male on point, MLPA, and 1 female, 1 male on slides, UCRC]; 20.v.2005, A. J. Sosa, J. Dorado ("egg predator" of Megamelus sp. [later described as M. bellicus] colony on Pontederia cordata) [9 females on cards, CNCI (1), MLPA (2), UCRC (5), USNM (1), 1 male on card, UCRC]. "Summer 2005", A. J. Sosa, J. Dorado ("egg predator" of Megamelus sp. [later described as M. bellicus]) [3 males on cards, UCRC].
Comments. Although some authors
recently regarded Ootetrastichus as a
valid genus separate from Aprostocetus (Kostjukov, 2004; Yegorenkova et al., 2007),
we treat all these species in the subgenus
Aprostocetus (Ootetrastichus) to ensure
stability in this difficult group, until the
status of Ootetrastichus is clarified based on
a rigorous study of its species worldwide,
and its relationships with other subgenera
of Aprostocetus as well as other genera of
Tetrastichinae are better understood.
The holotype of A. (Ootetrastichus)
infulatus [in MLPA] was examined, it is
poorly mounted (the body is fragmented) on
slide labeled: 1. "Ootetrastichus infulatus Det. De Santis HOLOTIPO 1913/1 MUSEO
DE LA PLATA", 2. "PUNTA LARA (Pcia.
Buenos Aires") Col: De Santis II/1955 ♀".
Female of this species was redescribed, and
male newly described, by Luft Albarracin & Triapitsyn (2007), who also indicated
Chlorottetix fraterculus (Berg), Dalbulus
maidis (DeLong & Wolcott), Exitianus
obscurinervis (Stål), Syncharina punctatissima
(Signoret) (Cicadellidae), and Peregrinus
maidis (Ashmead) (Delphacidae) as its hosts
in Tucumán Province, Argentina.
One female (lacking both antennae)
and one male paralectotypes of A.
(Ootetrastichus) cupreus [both in USNM]
were also examined, they were designated
by LaSalle & Schauff (1992) and are labeled
as follows: 1. "Sea Level.", 2. "Windward
side St. Vincent, W. I. H. H. Smith", 3. "Tetrastichodes cupreus Ashm ♀ Type", 4.
[red] "Cotype No. 2480 U.S.N.M.", 5. [blue] "Paralectotype Aprostocetus cupreus LaSalle
+ Schauff 1992" (female glued to a short pin
inserted in a small card); and 1. "St. Vincent,
W. I. H. H. Smith 241", 2. "Tetrastichodes
cupreus Ash ♂ Type", 3. [red] "Cotype No.
2480 U.S.N.M.", 4. [blue] "Paralectotype
Aprostocetus cupreus LaSalle + Schauff
1992" (male on a point).
Aprostocetus (Ootetrastichus) yerbamatei Triapitsyn, sp. nov. (Figs 8-14)
Figs. 8-11. Aprostocetus (Ootetrastichus) yerbamatei sp. nov., female (holotype): 8, antenna; 9,
mesosoma; 10, metasoma; 11, forewing.
Description. Female (holotype and
paratypes). Body length 1288-1300 µm
(dry-mounted paratypes) or 1304-1636 µm (slide-mounted paratype and holotype,
respectively). Head mostly yellow and light
brown except eyes and ocelli dirty pink;
mesosoma and metasoma dorsally mostly
brownish (brown to dark brown with some
greenish metallic sheen) except two basal
gastral terga partially yellowish to light
brown, tegula bright yellow; scape and
anelli light brown, remainder of antennal
segments brown; legs mostly yellowish
except metacoxa and all apical tarsomeres
darker (brownish).
Antenna (Fig. 8) with scape minus short
radicle 4.4-4.6x as long as wide and almost
smooth; funicle (excluding 4 anelli, second
anellus very short) 3-segmented, F1 the
longest funicle segment, a little longer than
pedicel and notably longer than F2 or F3;
clava 2-segmented, apical claval segment with a spicula and 1.8-2.2x length of basal
claval segment; funicle and claval segments
with long hairs and each with at least 2 hairlike
longitudinal sensilla.
Mesosoma (Fig. 9) with pronotum
entire, with more or less conspicuous
sculpture; mesoscutum and scutellum faintly
longitudinally striate, midlobe of mesoscutum
and scutellum each with 2 pairs of setae,
scutellar placoid sensilla close to posterior
margin of scutellum. Metanotum and
propodeum with inconspicuous sculpture,
almost smooth.
Wings. Forewing (Fig. 11) 3.6-3.8x as
long as wide; venation extending to about
0.6x length of wing, disc almost hyaline,
mostly bare behind base of submarginal vein
and densely setose elsewhere; the longest
marginal seta 0.4-0.5x greatest width of
disc. Hind wing 10.7-13.0x as long as wide;
disc hyaline, bare behind base of venation
and densely setose elsewhere; the longest
marginal seta 1.4-1.9x greatest width of
disc.
Metasoma (Fig. 10) with gaster elongate
(particularly the apical gastral tergum),
notably longer than mesosoma. Ovipositor
occupying almost entire length of gaster,
slightly exserted beyond gastral apex;
ovipositor length:metatibia length ratio 2.7 - 2.9:1.
Measurements (µm) of the holotype. Body: 1636; head: 197; mesosoma: 418;
gaster: 984; ovipositor: 935. Antenna: scape:
148; pedicel: 70; F1: 77; F2: 58; F3: 57;
clava: 151. Forewing: 1113:308; longest
marginal seta: 127. Hind wing: 910:85;
longest marginal seta: 115.
Male (paratypes). Body length 1023 µm
(dry-mounted paratype). Similar to female
except for the normal sexually dimorphic
features such as color, antenna, and genitalia,
as follows. Head yellow except eyes and
ocelli dirty pink; mesosoma and metasoma
dorsally mostly grayish-dark brown with
some metallic sheen except dorsellum a
little lighter and two basal gastral terga
yellow; scape and anelli pale, remainder
of antennal segments slightly darker (light
brown); legs mostly yellowish except pro-and mesotibiae apically and all apical
tarsomeres darker (brownish). Antenna (Fig.
12) with scape about 2.9x as long as wide;
funicle (excluding 3 anelli) 4-segmented,
F1, F3 and F4 subequal in length, F2 slightly
longer; clava 3-segmented, apical segment
with a spicula; funicle and claval segments
with long hairs and each with at least 2 hairlike
longitudinal sensilla (except only 1 such
sensillum on F1). Forewing (Fig. 13) about
4.0x as long as wide, the longest marginal
seta about 0.5x greatest forewing width; hind
wing about 12.0x as long as wide; discs of
forewing and hind wing hyaline. Genitalia (Fig. 14) typical for the subgenus.
Figs. 12-14. Aprostocetus (Ootetrastichus) yerbamatei sp. nov., male (paratype): 12, antenna; 13,
forewing; 14, genitalia.
Diagnosis. In addition to the distinguishing characters mentioned in the keys above, also see the diagnosis of A. (Ootetrastichus) riverplaticus sp. nov.
Etymology. The specific name refers to "yerba mate" (Ilex paraguariensis A. Saint-Hilaire), from which mate, first author's favorite drink in Argentina, is prepared.
Hosts. Megamelus bellicus Marino de Remes Lenicov & Sosa, M. scutellaris Berg, and Megamelus sp.
Type material. Holotype female [MLPA] on slide labeled: "ARGENTINA: Buenos Aires, Otamendi, 5.vii.2005, A. Sosa and J. Dorado. Egg predator of Megamelus scutellaris Berg on water hyacinth, Eichhornia crassipes. Mounted at UCR/ERM by V. V. Berezovskiy 2005 in Canada balsam". The type locality is Ingeniero Otamendi. Paratypes: ARGENTINA, Buenos Aires: Ingeniero Otamendi, 5.vii.2005, A. J. Sosa, J. Dorado (from eggs of M. scutellaris on water hyacinth) [1 male on card and 1 male on slide, UCRC]. "Summer 2005", A. J. Sosa, J. Dorado ("egg predator" of Megamelus sp. [later described as M. bellicus]) [3 females on cards, MLPA, UCRC, USNM, and 1 female on slide, UCRC].
Other material examined. ARGENTINA, Formosa: Herradura, "Laguna del Vivero" (an unnamed old meander of Río Paraguay near a nursery), 26°29'27''S 58°18'17''W, 61 m: 23.xi.2004, G. J. Cabrera, M. C. Hernández (emerged from petioles of water hyacinth infested with eggs of Taosa sp. (Dictyopharidae) and likely also of Megamelus sp.) [1 female, 1 male, UCRC]; 18.ii.2008, G. J. Cabrera, M. C. Hernández (emerged from petioles of water hyacinth infested with eggs of Megamelus sp. and Taosa (Cuernavaca) longula Marino de Remes Lenicov (Hemiptera: Dictyopharidae)) [3 females, UCRC]. Palo Santo, 9.i.2002, H. A. Cordo, M. C. Hernández (from petiole of water hyacinth with eggs of M. scutellaris) [1 female, 2 males, UCRC].
Mymaridae
Anagrus (Anagrus) empanadus Triapitsyn, sp. nov. (Figs 18-23)
Figs. 18-21. Anagrus (Anagrus) empanadus sp. nov., female: 18, antenna (paratype); 19, mesosoma
(holotype); 20, metasoma (holotype); 21, forewing (holotype).
Description. Female (holotype and
paratypes). Body length 594-693 µm (drymounted
specimens) or 836-873 µm (slidemounted
specimens). Face and vertex
yellow except trabeculae and stemmaticum
dark brown; scape and pedicel light
brown, flagellum brown; pronotum pale,
mesoscutum brown, anterior scutellum light
brown, posterior scutellum lemon yellow,
propodeum yellow except brown medially;
legs mostly light brown; median and apical
gastral terga yellow, remainder of gastral
terga brown, ovipositor sheaths light brown.
Head about as wide as mesosoma.
Antenna (Fig. 18) with scape 3.0-3.4x
as long as wide, with cross-ridges, a little
shorter than clava; pedicel much longer than
F1 (the shortest funicle segment); F2, F6, and
often F4 the longest funicle segments (F6
sometimes slightly longer than F2 and F4),
F3 and F5 slightly shorter (F5 sometimes
almost as long as F4); F1-F3 and F5 without
longitudinal sensilla, F4 with 1 longitudinal
sensillum, and F6 with 2 such sensilla; clava
2.7-2.8x as long as wide (in lateral view),
with 5 longitudinal sensilla.
Mesosoma (Fig. 19) about 0.5x as long as
metasoma. Mesoscutum with a pair of short,
weak adnotaular setae.
Forewing (Fig. 21) a little shorter than
body, 10.1-10.7x as long as wide; disc
slightly, inconspicuously infumate, with
an incomplete median row of setae and
a few additional setae in the middle; the
longest marginal seta about 3.3x maximum
wing width. Lengths of distal and proximal
macrochaetae in ratio 3.2-3.4:1. Hind wing
29-32x as long as wide, disc with a row of
setae along each margin; the longest marginal
seta 7.2-7.5x maximum wing width.
Metasoma (Fig. 20). Ovipositor long,
anteriorly usually overlapping mesophragma
and posteriorly exserted beyond apex of gaster by 0.33-0.36x own length (ratio of total
ovipositor length to length of its exserted part
2.7-2.8:1). External plate of ovipositor with 2
setae. Ovipositor length: protibia length ratio
about 4.4:1.
Measurements (µm) of the holotype.
Body: 836; head: 141; mesosoma: 246;
metasoma: 449; ovipositor: 670. Antenna:
scape: 94; pedicel: 42; F1: 18; F2: 55; F3: 46;
F4: 52; F5: 48; F6: 55; clava: 106. Forewing:
652:61; longest marginal seta: 203. Hind
wing: 615:21; longest marginal seta: 152.
Male (paratypes). Body length 528-561 µm (dry-mounted specimens). Similar
to female except for the coloration and
normal sexually dimorphic features such
as antenna and genitalia, as follows. Color
notably darker than in female: body mostly
brown except posterior scutellum pale.
Antenna (Fig. 22) with scape plus radicle
about 2.8x as long as wide. Forewing about
9.8x as long as wide, a little wider than in
female. Genitalia (Fig. 23) similar in shape
and structure to those of the Neotropical
species A. (Anagrus) amazonensis Triapitsyn,
Querino & Feitosa, A. (Anagrus) brasiliensis
Triapitsyn, A. (Anagrus) lineolus Triapitsyn,
and A. (Anagrus) urichi Pickles (Triapitsyn,
1997, 2000, 2002; Triapitsyn et al., 2008).
Figs. 22, 23. Anagrus (Anagrus) empanadus sp. nov., male (paratype): 22, antenna; 23, genitalia.
Diagnosis. Member of the incarnatus species group of the nominate subgenus Anagrus (Anagrus Haliday), as defined by Chiappini et al. (1996). In the keys to the Argentinean and Neotropical species of Anagrus Haliday by Triapitsyn (2000, 2002), respectively, A. (Anagrus) empanadus sp. nov. would key to the same couplet with A. (Anagrus) lineolus, to which it is most similar. The female of A. (Anagrus) empanadus differs from that of A. (Anagrus) lineolus in lacking a longitudinal sensillum on F5 of the antenna and also in having a much longer ovipositor, which is exserted beyond apex of the gaster by 0.33-0.36x own length (the ovipositor length: protibia length ratio is about 4.4:1). In A. (Anagrus) lineolus, which is known from Argentina, Brazil, Mexico, Peru, and Florida, USA (Triapitsyn, 2002), the ovipositor is exserted beyond apex of the gaster by at most 0.11x own length (the ovipositor length: protibia length ratio is 1.9-2.1:1) (Triapitsyn, 2000). Anagrus (Anagrus) empanadus is also similar to the recently described A. (Anagrus) amazonensis from Brazil, whose female has a longitudinal sensillum on F5 of the antenna and also a much shorter ovipositor, which is exserted beyond apex of the gaster by at most 0.07x own length (the ovipositor length: protibia length ratio is 2.0-2.1:1) (Triapitsyn et al., 2008).
Etymology. The specific name refers to "empanada(s)", first author's favorite food in Argentina.
Host. Megamelus scutellaris Berg.
Type material. Holotype female [MLPA] on slide labeled: "ARGENTINA: Buenos Aires, Otamendi, 5.vii.2005, A. Sosa and J. Dorado. Ex eggs of Megamelus scutellaris Berg on water hyacinth (Eichhornia crassipes). Mounted at UCR/ERM by V. V. Berezovskiy 2005 in Canada balsam". The type locality is Ingeniero Otamendi. Paratypes: ARGENTINA, Buenos Aires: Ingeniero Otamendi, 5.vii.2005, A. J. Sosa, J. Dorado (from eggs of M. scutellaris on water hyacinth) [10 females on cards, CNCI (1), MLPA (2), UCRC (6), USNM (1), 2 males on cards, MLPA, UCRC, and 1 male on slide, UCRC]. Near Ingeniero Otamendi, Río Paraná de las Palmas shore, 34º10'52.7''S 58º52'12.8''W, 6 m, 23.i.2003, S. V. Triapitsyn, M. C. Hernández, total sweeping [1 female on slide, UCRC].
Kalopolynema (Kalopolynema) poema Triapitsyn & Berezovskiy (Figs 24, 25)
Figs. 24, 25. Kalopolynema (Kalopolynema) poema Triapitsyn & Berezovskiy, female (paratype): 24,
antenna; 25, forewing.
Kalopolynema (Kalopolynema) poema Triapitsyn & Berezovskiy, 2002: 614-616.
Kalopolynema poema: Sosa et al., 2004: 274
(host information); Sosa et al., 2005:
71 (host information).
Comments. See Triapitsyn & Berezovskiy (2002) for the detailed description and diagnosis of K. (Kalopolynema) poema, originally described from two female specimens collected at the USDA-ARS South American Biological Control Laboratory in Hurlingham, Buenos Aires, Argentina. The female antenna (Fig. 24) and forewing (Fig. 25) are illustrated here to facilitate its recognition. The male of this species is unknown.
Host. Megamelus scutellaris Berg (Triapitsyn & Berezovskiy, 2002; Sosa et al., 2004, 2005).
Material examined. ARGENTINA, Buenos Aires: near Ingeniero Otamendi, Río Paraná de las Palmas shore, 34º10'52.7''S 58º52'12.8''W, 6 m, 23.i.2003, S. V. Triapitsyn, M. C. Hernández [1 female, UCRC]. Tigre, 34°23'50''S 58°34'32''W, 5 m, G. A. Logarzo: 9-16.xi.2005 [1 female, UCRC]; 2–11.ii.2006 [2 females, MLPA, UCRC].
Platygastridae: Scelioninae
Cremastobaeus atratus Loiácono & Mulvani (Figs 26-29)
Figs. 26-29. Cremastobaeus atratus Loiácono & Mulvani (Palo Santo, Formosa, Argentina): 26, female
antenna; 27, female mesosoma and metasoma; 28, female forewing; 29, male antenna.
Cremastobaeus atratus Loiácono & Mulvani, 1987: 16-18, 20 (measurements), 23-24 (illustrations); Johnson, 1992: 365 (catalog).
Comments. Species of the almost cosmopolitan genus Cremastobaeus Ashmead were reviewed by Loiácono & Mulvani (1987) mainly based on the material collected by A. A. Ogloblin in Loreto, Misiones, Argentina. This is the first record of C. atratus outside of its type locality in Loreto. To facilitate recognition of this species, here we provide illustrations of the female antenna (Fig. 26), mesosoma and metasoma (Fig. 27), and forewing (Fig. 28) as well as of the male antenna (Fig. 29).
Host. Megamelus scutellaris Berg. However, this host association is tentative due to the collecting method described in "Material and methods"; if confirmed, that would be the first known host record for the genus besides the possible host association with Gryllidae (Orthoptera) (Masner & Hanson, 2006).
Material examined. ARGENTINA, Formosa, Palo Santo, 9.i.2002, H. A. Cordo, M. C. Hernández (from petiole of water hyacinth with eggs of M. scutellaris) [2 females, 3 males, UCRC].
Parascelio sabcli Triapitsyn, sp. nov. (Figs 30-32)
Figs. 30-32. Parascelio sabcli sp. nov., female (holotype): 30, antenna; 31, mesosoma (posterior part
only) and metasoma; 32, fore- and hind wings.
Description. Female (holotype and
paratypes). Body length 2410–2520 µm.
Body mostly dark brown except fourth
gastral tergite and sternite almost entirely
light brown, remainder of gaster contrastingly
brown to dark brown. Scape, pedicel, and
funicle light brown to brown, clava dark
brown; legs light brown except tarsi a little
darker (brown).
Head with punctate-reticulate sculpture,
with short, weak hairs.
Antenna (Fig. 30) with scape about 4.5x
as long as wide and smooth; F1 almost as
long as pedicel and the longest funicle
segment, F3-F5 a little wider than F1 or F2;
clava about as long as funicle, with basal
four segments wider than long and the apical
segment a little longer than wide.
Mesosoma notably sculptured, with
pronotum short; scutellum with dense
pubescence (setae longer than on
mesoscutum). Metanotum medially with a
strong spine (Fig. 31).
Wings (Fig. 32). Forewing 3.5-3.6x as
long as wide; disc almost hyaline (at most
with a very slight brownish tinge), densely
setose; the longest marginal seta about 0.13x
greatest width of disc. Hind wing about 6.6x
as long as wide; disc almost hyaline (at most
with a very slight brownish tinge), densely
setose; the longest marginal seta 0.34-0.35x
greatest width of disc.
Legs. Coxae smooth.
Metasoma (Fig. 31) with strong sculpture
on three basal tergites. Ovipositor occupying
almost entire length of gaster, a little exserted
beyond gastral apex (by 0.03–0.12x own
length); ovipositor length:metatibia length
ratio about 2.6:1.
Measurements (µm) of the holotype.
Body: 2520; head: 363; mesosoma: 677;
gaster: 1480; ovipositor: 1433. Antenna:
scape: 230; pedicel: 100; F1: 97; F2: 51; F3:
48; F4: 40; F5: 40; clava: 279. Forewing:
1660:467; longest marginal seta: 62. Hind
wing: 1298:197; longest marginal seta: 68.
Male. Unknown.
Diagnosis. The female of P. sabcli sp.
nov. differs from those of the previously
described congeneric species by the color of
the gaster, as indicated in the key below.
The generic diagnoses of the Neotropical
genus Parascelio Dodd were given by
Masner (1976) and Austin & Field (1997).
The genus has not been previously recorded
from Argentina. Prior to this study there
were no keys available to separate the three
described species.
Etymology. The species is named after the USDA-ARS South American Biological Control Laboratory (SABCL).
Host. Megamelus scutellaris Berg. This host association is tentative due to the collecting method described in "Material and methods"; if confirmed, that would be the first known host record for the genus.
Type material. Holotype female [MLPA] on slide labeled: 1. "ARGENTINA: Formosa, Palo Santo, 9.i.2002, C. Hernández "Prs./ Megamelus sp.". Mounted at UCR/ERM by V. V. Berezovskiy 2008 in Canada balsam"; 2. "Parascelio Det. L. Masner, 2006". Paratypes: same data as the holotype [2 females on points, CNCI, UCRC]. The collectors were H. A. Cordo (in the field) and M. C. Hernández (in the laboratory), parasitoids emerged from petioles of water hyacinth infested with eggs of M. scutellaris.
Key to the species of Parascelio (females)
1. Body mostly orange-yellow ....................................................... P. ruber (Szabó)
1´. Body mostly dark brown or black ......................................................................... 2
2. Gaster entirely dark brown or black ..................................................................... 3
2´. Gaster with fourth gastral tergite and
sternite almost entirely light brown,
remainder of gaster contrastingly brown to
dark brown ....... P. sabcli Triapitsyn, sp. nov.
3. F3 and F4 yellow ........................................................................ P. undulatus Dodd
3´. F3 and F4 brown ......................................................................... P. molnari (Szabó)
ACKNOWLEDGEMENTS
We thank Vladimir V. Berezovskiy (UCRC) for mounting the specimens; Lubomír Masner (CNCI) for the generic identifications of Parascelio sp. and Cremastobaeus sp.; Marta Loiácono (MLPA) for the identification of Cremastobaeus atratus and also for arranging a loan of the holotype of Aprostocetus (Ootetrastichus) infulatus; John La Salle (Australian National Collection of Insects, CSIRO Entomology, Canberra, Australian Capital Territory, Australia) for valuable comments on the status of Aprostocetus (Ootetrastichus) and help with the literature; Terry Nuhn (USNM) for the loan of type specimens of Aprostocetus (Ootetrastichus) cupreus; and Guillermo A. Logarzo (USDAARS South American Biological Control Laboratory, Hurlingham, Buenos Aires, Argentina) for collecting many interesting specimens of Mymaridae in Argentina. Jennifer Walker (UCRC) prepared some of the illustrations.
LITERATURE CITED
1. ASHMEAD, W. H. 1894. Report on the parasitic Cynipidae, part of the Braconidae, the Ichneumonidae, the Proctotrypidae, and part of the Chalcididae.–Part II, pp. 108-188. In: Riley, C. V., Ashmead, W. H. & L. O. Howard. Report upon the parasitic Hymenoptera of the island of St. Vincent. J. Linn. Soc. Zool. 25: 56-254.
2. AUSTIN, A. D. & S. A. FIELD. 1997. The ovipositor system of scelionid and platygastrid wasps (Hymenoptera: Platygastroidea): comparative morphology and phylogenetic implications. Invert. Taxon. 11: 1-87.
3. CHIAPPINI, E., S. V. TRIAPITSYN & A. DONEV. 1996. Key to the Holarctic species of Anagrus Haliday (Hymenoptera: Mymaridae) with a review of the Nearctic and Palaearctic (other than European) species and descriptions of new taxa. J. Nat. Hist. 30: 551-595.
4. DE SANTIS, L. 1957. Descripción de nuevos géneros y especies de calcidoideos argentinos. I (Hymenoptera). Not. Mus. Zool. 19 (166): 33-72.
5. DE SANTIS, L. 1979. Catálogo de los himenópteros calcidoideos de América al sur de los Estados Unidos. Publicación especial, Comisión de Investigaciones Científicas de la provincia de Buenos Aires, La Plata, 488 pp.
6. GIBSON, G. A. P. 1997. Morphology and terminology. In: Gibson, G. A. P., J. T. Huber & J. B. Woolley (eds), Annotated keys to the genera of Nearctic Chalcidoidea (Hymenoptera), NRC Research Press, Ottawa, Ontario, Canada, pp. 16-44.
7. HOWARD, L. O. 1897. On the Chalcididae of the Island of Grenada, BWI. J. Linn. Soc. Zool. 26: 129-178.
8. JOHNSON, N. F. 1992. Catalog of world species of Proctotrupoidea, exclusive of Platygastridae (Hymenoptera). Mem. Am. Entomol. Inst. 51: i-v +1-825.
9. KOSTJUKOV, V. V. 2004. [On the status of the subgenera of the genus Aprostocetus Westwood, 1833 (Hymenoptera, Eulophidae, Tetrastichinae) with description of Stepanovia, gen.n.] In: Nadikti, V. D., V. Y. Ismailova, G. I. Levashova & E. S. Sugonjaev (eds), [Biological protection of plants is the basis of stabilization of agroecosystems], Proc. Intern. Sci.-Pract. Conf., Krasnodar, 2004, 1, pp. 36-44. [In Russian.]
10. LASALLE, J. & M. E. SCHAUFF. 1992. Preliminary studies on Neotropical Eulophidae (Hymenoptera: Chalcidoidea): Ashmead, Cameron, Howard and Walker species. Contr. Am. Entomol. Inst. 27 (1): 1-47.
11. LOIÁCONO, M. S. & S. H. MULVANI. 1987. Sistemática y análisis fenético de seis nuevas especies del género Cremastobaeus Ashmead 1893 (Hymenoptera– Proctotrupoidea). Rev. Asoc. Cienc. Nat. Litoral 18 (1): 13-28.
12. LUFT ALBARRACIN, E. & S. V. TRIAPITSYN. 2007. Aprostocetus (Ootetrastichus) infulatus (Hymenoptera: Eulophidae): description of the male, new distribution and first host records. Zootaxa 1438: 65-68.
13. MARIANI, R., A. SOSA & A. M. MARINO DE REMES LENICOV. 2007. Megamelus bellicus (Hemiptera: Delphacidae): immature stages and biology. Rev. Soc. Entomol. Argent. 66 (3-4): 189-196.
14. MASNER, L. 1976. Revisionary notes and keys to world genera of Scelionidae (Hymenoptera: Proctotrupoidea). Mem. Entomol. Soc. Can. 97: 1-87.
15. MASNER, L. & P. E. HANSON. 2006. Familia Scelionidae. In: Hanson, P. E. & I. D. Gauld (eds), Hymenoptera de la región neotropical. Mem. Am. Entomol. Inst. 77, pp. 254-265.
16. SOSA, A. J., A. M. MARINO DE REMES LENICOV, R. MARIANI & H. A. CORDO. 2004. Redescription of Megamelus scutellaris Berg (Hemiptera: Delphacidae), a candidate for biological control of water hyacinth. Ann. Entomol. Soc. Am. 97 (2): 271-275.
17. SOSA, A. J., A. M. MARINO DE REMES LENICOV, R. MARIANI & H. A. CORDO. 2005. Life history of Megamelus scutellaris with description of immature stages (Hemiptera: Delphacidae). Ann. Entomol. Soc. Am. 98 (1): 66-72.
18. SOSA, A. J., H. A. CORDO & J. SACCO. 2007a. Preliminary evaluation of Megamelus scutellaris Berg (Hemiptera: Delphacidae), a candidate for biological control of waterhyacinth. Biol. Contr. 42 (2): 129-138.
19. SOSA, A. J., A. M. MARINO DE REMES LENICOV & R. MARIANI. 2007b. Species of Megamelus (Hemiptera: Delphacidae) associated with Pontederiaceae in South America. Ann. Entomol. Soc. Am. 100 (6): 798-809.
20. TRIAPITSYN, S. V. 1997. The genus Anagrus (Hymenoptera: Mymaridae) in America south of the United States: a review. Ceiba 38 (1): 1-12.
21. TRIAPITSYN, S. V. 2000 [1999]. A review of the species of Anagrus Haliday, 1833 (Hymenoptera: Mymaridae) collected by A. A. Ogloblin in Argentina. Rus. Entomol. J. 8 (3): 213-222.
22. TRIAPITSYN, S. V. 2002. Descriptive notes on a new and other little known species of Anagrus Haliday, 1833 (Hymenoptera: Mymaridae) from the New World tropics and subtropics. Entomotropica 17 (3): 213-223.
23. TRIAPITSYN, S. V. & V. V. BEREZOVSKIY. 2002. Revision of Kalopolynema, with notes on Platypolynema (Hymenoptera: Mymaridae). Fla. Entomol. 85 (4): 611-619.
24. TRIAPITSYN, S. V., R. B. QUERINO & M. C. B. FEITOSA. 2008. A new species of Anagrus (Hymenoptera: Mymaridae) from Amazonas, Brazil. Neotrop. Entomol. 37 (6): 681-684.
25. WHALLEY, P. E. S. 1956. On the identity of species of Anagrus (Hym., Myrmaridae [sic]) bred from leafhopper eggs. Entomol. Mon. Mag. 92: 147-149.
26. YEGORENKOVA, E. N., Z. A. YEFREMOVA & V. V. KOSTJUKOV. 2007. Contributions to the knowledge of tetrastichine waps (Hymenoptera, Eulophidae, Tetrastichinae) of the Middle Volga Region. Entomol. Rev. 87 (9): 1180-1192.