Reclassification of Bracon mendocinus, a gall-associated doryctine wasp, and description of a new closely related species of Allorhogas (Hymenoptera: Braconidae)
Author
Martinez, Juan J.
Author
Zaldivar-Riverón, Alejandro
Author
Sáez, Alberto G.
text
Journal of Natural History
2008
2010-12-02
42
41 - 42
2689
2701
http://dx.doi.org/10.1080/00222930802354134
journal article
10.1080/00222930802354134
1464-5262
5224352
Allorhogas mendocinus
(Kieffer and Jörgensen)
comb. nov.
(
Figures 2A,C,E
,
3A,E
,
4A,B
)
Bracon mendocinus
Kieffer and Jörgensen 1910
, p. 414
Diagnosis
Allorhogas mendocinus
can be distinguished from all other species of
Allorhogas
except
A. joergenseni
sp. nov.
by the rugose head and mesoscutum and the obscured or weak notauli. Following Marsh’s key to species of
Costa Rica
(
Marsh 2002
), the latter two species may be more related to
A. rugosus
Marsh
, which has rugulose mesonotal lobes at least along the notauli, although in the species treated here the sculpture is much coarser. Additionally,
A. rugosus
has bigger eyes (maximum diameter about three times the length of the malar space), honey brown in colour, and with inner orbits emarginated near the toruli.
Allorhogas mendocinus
is distinguished from
A. joergenseni
sp. nov.
by its different metasomal sculpture. In
A. mendocinus
, the metasomal terga beyond tergum III are entirely coriaceous, whereas in
A. joergenseni
these are striate basally and weakly punctate to smooth apically. In addition, frons excavation is not as conspicuous in
A. mendocinus
as in
A. joergenseni
.
Figure 2 (A,C,E)
Allorhogas mendocinus
: (A) head in anterior view; (C) frons in anterior view; (C) mesoscutum in dorsal view. (B,D,F)
Allorhogas joergenseni
sp. nov.
: (B) head in anterior view; (D) frons in anterior view; (F) mesoscutum in dorsal view.
Figure 3 (A,E)
Allorhogas mendocinus
: (A) propodeum in dorsal view; (E) fourth and fifth metasomal terga in dorsal view. (B–D,F)
Allorhogas joergenseni
sp. nov.
: (B) propodeum in dorsal view; (C) metasoma in dorsal view; (D) metasomal tergum I on dorsal and anterior view; (F) fourth and fifth metasomal terga in dorsal view.
Figure 4 (A,B)
Allorhogas mendocinus
: (A) forewing; (B) hindwing. (C,D)
Allorhogas joergenseni
sp. nov.
: (C) forewing; (D) hindwing. Scale: 0.5 mm.
Female
Body length
2.6 mm
, forewing
1.9 mm
.
Colour
. Head and mesosoma orange-red, apex of antenna and metasoma beyond tergum I black, telotarsi darkened, forewing hyaline basally and very weakly infuscate beyond vein M; veins brown, except veins C+SC+R, M+CU and 1-1A which are light brown to yellow; pterostigma brown, hindwing entirely hyaline.
Head
. Transverse, about twice as wide as long, 18 antennomeres; occipital carina present and complete, reaching hypostomal carina; face, vertex and temples coarsely rugose (
Figure 2A
), except for an almost smooth narrow median line from clypeus to toruli; frons weakly excavated (
Figure 2C
); oral cavity small, shorter than malar space; eye moderate sized, 1.5 to 2 times the length of the malar space, with inner orbits uniformly rounded; temples narrow, shorter than eye width.
Mesosoma
. Relatively short and compact, 1.5 to 1.7 times longer than high and about as high as wide. Pronotum rugose, pronotal collar not distinct, pronotal furrow rugose. Mesoscutum (
Figure 2E
) transverse in dorsal view and strongly declivous anteriorly, 0.6 to 0.7 times as long as wide, anterior edge strongly directed anteriorly, apical face forming an acute angle with dorsal face in lateral view; coarsely rugose; notauli completely obscured by sculpture. Scutellum weakly acinose. Propodeum (
Figure 3A
) rugose–areolate, declivous posteriorly, without distinct carina or areola, with two somewhat more evident divergent carinae directed posteriorly and laterally from the median anterior edge. Mesopleuron rugose to acinose, subalar groove rugose, sternaulus half as long as mesopleuron.
Legs
. Foretibia with a row of seven spines along the anterior margin, hind coxa mostly rugose with a small but distinct basal tubercule.
Wings
. Forewing (
Figure 4A
) with pterostigma short and broad, second submarginal cell closed at apex; first subdiscal cell open apically; r shorter than 3RS; 2cu-a absent; RS+Ma sinuate; RS+Mb very short. Hindwing (
Figure 4B
) with vein m-cu nebulous and weakly curved towards wing apex.
Metasoma
. Tergum I always wider than long, striate, anterior area clearly delimited by carinae and punctate; raised median area not clearly defined by carinae, basal sternal plate one-quarter to one-third the length of tergum I. Terga II and III striate, fused, line separating second and third terga weakly indicated laterally; remainder of terga entirely coriaceous (
Figure 3E
); ovipositor sheaths 0.25 times as long as metasoma.
Male
Essentially as in female, with 23 to 24 antenommeres.
Material examined
Argentina
:
Neotype
female (
MACN
, here designated),
La Pampa
,
Parque Luro
,
22 February 2003
,
Martinez
coll.
Additional specimens:
two males
(
MACN
),
La Pampa
,
Santa Rosa
20 March 2006
, reared from galls of
L. chilense
, Martinez
coll
.
Biological observations
The new specimens assigned to
A. mendocinus
were reared from bud galls of
L. chilense
var.
chilense
(
Figure 5B
). These galls are identical to those described and illustrated by
Jörgensen (1917)
from the same plant species (
Figure 5A
). Although the last author mentioned the name
L. gracile
, this is a junior synonym of
L. chilense
var.
glaberrimum
. Galls on this plant species are oval, approximately
1 cm
long, with a stiliform process that is about as long as the gall, and pubescent and green when fresh but brownish and almost glabrous when dry. The tissue surrounding the single pupal chamber is spongy in both mature and dry galls. As mentioned by
Jörgensen (1917)
, galls are common during summer and it is possible that
A. mendocinus
produces more than one generation per year. Unlike the other gall-associated doryctines in the same locality (
Percnobracon
cf.
stenopterus
), which spend winter as mature larvae within galls and the adults emerge in spring, adults of
A. mendocinus
emerge in late summer or early autumn.
Figure 5 (A) Original illustration of galls on
Lycium chilense
from
Jörgensen (1917)
; (B) gall found on
L. chilense
.
In their study of gall insects from
Argentina
,
Kieffer and Jörgensen (1910)
proposed the name
Oligotrophus
(
?
)
lyciicola
for a hypothetic gall-inducing cecidomyiid (
Diptera
) species that could not be reared or observed within the galls, but that was assumed to be the host of
A. mendocinus
and other parasitic
Hymenoptera
. During the surveys made for this study, no adult cecidomyiid flies were reared from galls of
L. chilense
and no cecidomyiid larvae or pupae remains were observed within the pupal chambers. This, together with the current knowledge of gall induction by other species of
Allorhogas
, strongly suggests that
A. mendocinus
actually is the species that induces the galls on
L. chilense
. However, the absence of remains of the host after parasitoid emergence is known to occur in various parasitic species, and therefore further observations are needed to confirm the existence of the above cecidomyiid species.