The New World ant parasitoid genus Orasema (Hymenoptera: Eucharitidae)
Author
Baker, Austin J.
Author
Heraty, John M.
text
Zootaxa
2020
2020-11-30
4888
1
1
84
journal article
9442
10.11646/zootaxa.4888.1.1
da69a4c8-2962-4d6d-9abf-627b77bb9116
1175-5326
4297699
574A35A5-A551-4A7E-B2BC-481D703B1BE7
Orasema sixaolae
Wheeler & Wheeler
urn:lsid:zoobank.org:act:
4CB6983B-FC4A-4DCD-90D5-D4974A1AE2C1
(
Fig. 24
)
Orasema sixaolae
Wheeler & Wheeler 1937: 163–164
.
Diagnosis.
Distinguished from
O. brachycephala
by the flagellomeres being as wide as long (cup-shaped) with distinct peduncles (
Fig. 24D, E
) and the petiole much longer than the hind coxa. Distinguished from
O. tinalandia
by having more coarsely reticulate sculpture on the mesoscutal midlobe (
Fig. 24F
) and the petiole much longer than the hind coxa.
This species is most similar to
O. nebula
but can be recognized by the more coarsely reticulate sculpture on the face (
Fig. 24B
), a generally larger MSP:EYH that gives the head a more triangular, less circular appearance, and a longer/thinner petiole in both sexes.
Description. Female.
Length
1.5–2.1 mm
(
Fig. 24A
).
Color.
Head and mesosoma dark with iridescence. Mandible brown; Femora mostly brown, tips pale; tibiae yellow.
Head
(
Fig. 24B
). Head in frontal view subquadrate; HW:HH = 1.1–1.2; face completely reticulate to slightly costate on frons; longitudinal groove between eye and torulus present; eyes bare, IOD:EH = 1.5–1.8; MS:EH = 0.6–0.9; malar depression absent; supraclypeal area as long as broad, equal to length of clypeus, smooth; clypeus smooth to shallowly reticulate; epistomal sulcus vaguely defined. Labrum with 4 or 5 digits. Mandibular formula 3:2; palpal formula 3:2. Occiput with dorsal margin evenly rounded; temples absent. Pedicel globose, broader than F1. FL:HH = 1.1–1.3; anellus disc-shaped; F2L:F2W = 1.0–1.5, F2L:F3L = 1.0–1.2; following funiculars subequal in length, gradually broader; clava subovate (
Fig. 24D
).
Mesosoma
(
Fig. 24C, F
). ML:MH = 1.1–1.4. Mesoscutal midlobe reticulate, bare or with very minute setae; lateral lobe smooth. Axilla smooth; scutoscutellar sulcus broad, irregularly foveate, narrowly separated from transscutal articulation; mesoscutellar disc slightly longer than broad, reticulate; frenal line regularly foveate; axillular sulcus indicated by a weak longitudinal carina. Propodeal disc with median carina, smooth laterally (
Fig. 24G
); callus with several short setae on dorsal margin. Prepectus, mesepisternum, and propleuron reticulate. HCL:HCW = 1.7–2.3; HFL:HFW = 6.1–7.0, evenly covered with short, dense setae. FWL:FWW = 2.3–2.5, FWL:ML = 2.4–2.8; basal third of wing bare, including speculum and costal cell, wing disc densely setose; submarginal vein bare; stigmal vein perpendicular to anterior wing margin; postmarginal vein several times longer than stigmal vein. Hind wing costal cell with a broad bare area.
Metasoma.
PTL:PTW = 3.1–4.2, PTL:HCL = 1.1–1.4, areolate-reticulate, lateral margin rounded, ventral sulcus present with margins narrowly separated. Antecostal sulcus foveate; acrosternite posteriorly rounded; apical setae of hypopygium present, minute. Ovipositor with subapical carina present; first (ventral) valvula with 6–8 small, narrowly separated teeth, second (dorsal) valvula with 6 or 7 annuli that are broadly separated dorsally by smooth area.
Male.
Length 1.5–2.0 mm. HH:HW = 1.2–1.3. FL:HH = 1.3–1.5; F2L:F2W = 1.2–1.4 (
Fig. 24E
). Tibiae yellow. PTL:PTW = 6.2–7.8, PTL:HCL = 1.7–2.5.
Planidium.
Described by
Wheeler and Wheeler (1937)
.
Pupa.
Fits the general description for
Oraseminae
pupae provide by
Heraty (1994)
, with three large tubercles along the dorsal margin of the petiole and the prominent transverse abdominal ridges being the most diagnostic features of the subfamily. This species has stronger tubercles coming from the abdominal ridges than the pupa of
O. tolteca
(
Fig. 19D
).
Hosts.
Solenopsis tenuis
Mayr
in
Costa Rica
(
Wheeler & Wheeler 1937
) and
Solenopsis picea
Emery
in Mexico.
Both species of
Solenopsis
make their nests in dead twigs, where parasitized brood and
Orasema
pupae were found. In southern
Mexico
, dead twigs were placed as baits at coffee plantations to monitor
Solenopsis
activity, and
O. sixaolae
were found in many of these plantations (de la Mora Rodríguez
et al
., unpublished).
Plant associates.
Unknown, but possibly coffee,
Coffea arabica
(L.) (
Rubiaceae
).
FIGURE 24
.
Orasema sixaolae
. Female (UCRCENT00282692):
A
, habitus, lateral;
B
, head, anterior;
C
, mesosoma, lateral;
D
, antenna;
F
, mesosoma, dorsal;
G
, propodeum, posterior. Male (UCRCENT00247779):
E
, antenna.
Distribution
(
Fig. 21
).
Argentina
: BA, MN, SA;
Belize
: TO;
Brazil
: SP, MG;
Costa Rica
: AL, GU, HE, LI, PU;
Ecuador
: NA, OR;
Honduras
: OL;
Mexico
: CS, VE;
Peru
: MD;
Trinidad
: SL;
Venezuela
: BO. Specimens collected throughout the year.
Material examined.
Syntype
.
COSTA RICA
.
Limon
:
No. 375
Sixaola River
,
9
°
32’N
,
82°
42’W
,
vii.1924
,
G.C. Wheeler
[
1♀
, deposited in USNM: UCRCENT00248527]
.
Additional material examined.
62 specimens
, see supplementary material.
Discussion.
This species has the largest known distribution of any species in
Oraseminae
, even though it is far less morphologically diverse than
O. coloradensis
. Specimens of
O. sixaolae
have been collected at a fairly even rate throughout the year (49 records), indicating that tropical/subtropical species of
Orasema
are far less ephemeral than the temperate species found in the Nearctic. Despite their presence in previous collections, our sampling in
Trinidad
(2013) and
Costa Rica
(2016) failed to find any additional
O. sixaolae
.