Citation: Aguirre H, Shaw SR, Berry JA, de Sassi C (2014) Description and natural history of the first micropterous Meteorus species: M. orocrambivorus sp. n. (Hymenoptera, Braconidae, Euphorinae), endemic to New Zealand. Journal of Hymenoptera Research 38: 45–57. doi: 10.3897/JHR.38.7403
Wing reduction is well known in the cyclostome lineage of Braconidae, but very unusual in non-cyclostome groups. A new species from New Zealand, Meteorus orocrambivorus, the first micropterous species of the non-cyclostome and cosmopolitan genus Meteorus, is described. Phylogenetic analysis places it close to M. versicolor, a macropterous parasitoid of macrolepidoptera. Details about its host relationships, plant associations and habitat suggest that the necessity of succeeding in cryptic environments may explain the wing modification. A possible case of Batesian mimicry with ants could explain the extreme sexual dimorphism.
Wing reduction, sexual dimorphism, alpine habitat, parasitoid, Orocrambus
Wing reduction is relatively common within the New Zealand braconid fauna.
Wing reduction is displayed in varying degrees, from the total loss of structures associated with wings, including the tegula, to wings being structurally well-developed but too short to perform flight. To describe this variability,
The family Braconidae (Hymenoptera) is mainly comprised of winged species. However, wing reduction is a well-known phenomenon among the cyclostome lineage of Braconidae, since 90 species in 44 genera (1.2%) have been reported showing it (
Meteorus Haliday (Euphorinae: Meteorini) is a cosmopolitan genus of koinobiont parasitoids of Coleoptera and Lepidoptera larvae. Its most remarkable characteristic is the distinctive pendant (meteor-like) cocoon constructed by the last larval instar (
The sampling location was Glynn Wye station at Lewis Pass (42°22.78'S, 172°24'E), North Canterbury Region, New Zealand (Fig. 14). The Lewis Pass traverses the Southern Alps, which run north-south along much of the South Island of New Zealand. It is the most northern and lowest (907m) of the three main alpine passes which allow access between the west and east coasts.
All the Meteorus specimens were reared as solitary parasitoids of caterpillars of Orocrambus ramosellus Doubleday, Orocrambus simplex Butler (Lepidoptera: Crambidae) and Merophyas leucaniana (Walker) (Tortricidae). The caterpillars were collected by Claudio de Sassi from four locations (42°36.73'S, 172°27.78'E; 42°36.88'S, 172°27.62'E; 42°36.72'S, 172°26.58'E; 42°38.83'S, 172°22.17'E) at three elevations (650 m, 800 m, 1000 m) from November 2008 to January 2009. The sample sites comprise alpine and subalpine habitats dominated by a mixture of tussock grasses (Poa and Festuca), representing the native flora component, and exotic pastures accounting for the non-native component (
The caterpillars were hand-picked from the host plants Poa cita Edgar (silver tussock) and Festuca novae-zelandiae (Hack.) (Cockayne, fescue tussock), and subsequently reared to fate in the laboratory (i.e death of caterpillar or emergence of either adult moth or parasitoid). The collected parasitoids were preserved in vials with 95% ethanol, and sent to the University of Wyoming Insect Museum (UWIM).
Eleven specimens were pin-mounted for taxonomic description, 21 remained in alcohol from which 2 legs were sent to Julia Stigenberg at Stockholm University for DNA analyses as a part of her project about the phylogeny of Euphorinae. Morphological terminology follows
Occipital carina complete; ocelli small (ocelli-ocular distance 2.0–2.3× ocellar diameter in females, 1.7× in males); mandible stout and twisted; notauli smooth and not distinct in females, but deeply impressed, narrow, distinct and rugose in males; female micropterous, male macropterous; propodeum smooth in females, but rugulose-lacunose in males; tarsal claw without lobe; dorsope and laterope absent; ventral borders of first tergite almost touching distally; ovipositor 1.9–2.3× longer than first tergite).
Body color. Dark brown-ferruginous
Body length. 3.5 mm.
Head. (Fig. 3). Antenna with 16 flagellomeres; flagellar length/width ratios as follows: F1 = 2.6, F2 = 2.2, F3 = 1.9, F 14 = 1, F 15 = 0.9, F 16 = 2.0; head 1.1× wider than high; occipital carina complete; ocelli ocular distance 2.0× ocellar diameter; head height 1.4× eye height; temple length 0.7× eyes length in dorsal view; vertex in dorsal view not descending vertically behind the lateral ocelli; frons smooth and polished; maximum face width 1.4× minimum face width; face finely rugulose; minimum face width 0.7× clypeus width; clypeus punctate; malar space length 0.4× mandible width basally; mandible stout and twisted.
Meteorus orocrambivorus sp. n. 1 Female lateral habitus 2 Female head and mesonotum dorsal view. The arrow indicates the reduced wing 3 Female head frontal view 4 Female propodeum and first metasomal tergite dorsal view 5 Male lateral habitus 6 Male frontal view.
Mesosoma. (Figs 2, 4, 7 and 9). Pronotum in lateral view dorsally rugose; propleuron smooth and polished; notauli smooth and not distinct; mesonotal lobes not defined; mesoscutum smooth and polished; scutellar furrow with one carina; mesopleuron smooth but rugulose close to tegula; sternaulus long, wide and rugose; metapleuron mostly smooth, rugose close to the coxa; suture between propodeum and metapleuron foveate; propodeum smooth; absence of longitudinal and transversal carinae on propodeum; median depression on propodeum weakly present.
Contrasting differences between males and females. 7 female head and mesonotum dorsal view 8 male head and mesonotum dorsal view 9 female propodeum dorsal view 10 male propodeum dorsal view.
Wings. Very reduced, at most reaching the scutellum apex (Fig. 2).
Legs. Hind coxa slightly strigose dorsally; the remaining surface irregular and punticulate; hind femur 4.8× longer than it is wide; tarsal claw without lobe.
Metasoma. (Figs 1 and 4). Dorsope and laterope absent; ventral borders of first tergite almost touching distally; first tergite smooth and polished except the apical border with short and convergent costae; ovipositor 2.0× longer than first tergite; ovipositor both not thickened basally and straight.
Body length 3.0–3.1 mm; head with long and scattered setae; head 1.2× wider than high; ocelli ocular distance 2.3× ocellar diameter; head height 1.3× eye height; temples length 0.6× eyes length in dorsal view; maximum face width 1.3× minimum face width; face strigulate; minimum face width 0.8× clypeus width; malar space length 0.3–0.6× mandible width basally; pronotum in lateral view dorsally lacunose-foveate, faintly costate ventrally; sternaulus carinate-foveate; propodeum smooth except a small, punctate patch dorsally; hind coxa either strigate-punctate, strigate, or with very small and disperse punctures; hind femur 4.6–5.2× longer than it is wide; ventral borders of first tergite touching for a short distance; first tergite with costae convergent, faintly demarcated; T2 and T3 slightly coriaceous; ovipositor 1.9–2.3× longer than first tergite; ovipositor neither thickened basally nor curved.
(Figs 5, 6, 8 and 10). Body black except the head with a small testaceous patch on the temple behind the eye; wings hyaline; body length 3.7 mm; antenna with 27 flagellomeres; ocelli ocular distance 1.7× ocellar diameter; head height 1.6× eye height; temples length 0.8–0.9× eyes length in dorsal view; vertex in dorsal view not descending vertically behind the lateral ocelli; maximum face width 1.2× minimum face width; minimum face width equal to clypeus width; malar space length 0.7–0.9× mandible width basally; propleuron puncticulate and shiny; notauli deeply impressed, narrow, distinctive and rugose, with pronounced longitudinal carina; mesoscutal lobes well defined; central lobe of mesoscutum punctate; scutellar furrow with seven carinae; mesopleuron smooth and polished; sternaulus rugose; propodeum rugulose-lacunose; longitudinal and transversal carinae on propodeum absent; median depression on propodeum absent; hind coxa with very small and dispersed punctures; wing length 3.6–3.7 mm; second submarginal cell of fore wing not strongly narrowed anteriorly; vein r 0.5× length of 3Rsa (fore wing); vein 3RSa 0.8× length of r-m (fore wing); vein m-cu of fore wing postfurcal; vein 1M 0.8–1× length of cu-a (HW); vein 1M 0.8× length of 1r-m (hind wing); dorsope and laterope absent; apparent dorsopes as deep grooves in the common dorsopes location; first tergite with faintly demarcated and parallel costae, which become more obvious on the apical border.
The micropterous condition of Meteorus orocrambivorus females is unique among all known Meteorus. However if the males are compared with the rest of the New Zealand fauna, Meteorus orocrambivorus seems closest to Meteorus cobbus Huddleston (
Holotype. Female (point-mounted). NEW ZEALAND, South Island, Lewis Pass, Hope River Valley, Glynn Wye Station, 42°36.73'S, 172°27.78'E, 650 m; host plant Poa cita Edgar (silver tussock), host caterpillar Orocrambus ramosellus Doubleday (Crambidae); collected as solitary parasitoid during the period November 2008 to January 2009; Claudio de Sassi, collector.
Paratypes. Two females and seven males same data as the holotype; one female same data as holotype except collected at 42°36.88'S, 172°27.62'E, 800 m; two females and two males same data as holotype except collected at 42°36.72'S, 172°26.58'E; three females and two males same data as holotype except the host caterpillar collected feeding on Festuca novae-zelandiae (Hack.) Cockayne at 1000 m; one female same data as holotype except the host caterpillar collected feeding on Festuca novae-zelandiae at 42°36.88'S, 172°26.58'E; one female same data as holotype except the host caterpillar collected feeding on Festuca novae-zelandiae at 42°36.88'S, 172°26.58'E, 650 m; six females and four males same data as holotype except the host caterpillar collected feeding on Festuca novae-zelandiae at 42°36.88'S, 172°26.58'E, 1000 m; one female and one male same data as holotype except the host caterpillar collected feeding on Festuca novae-zelandiae at 42°38.83'S, 172°22.17'E, 650 m.
NEW ZEALAND, South Island, Lewis Pass, Hope River Valley, Glynn Wye Station.
(Fig. 11). Length 4.4 mm; width 1.6 mm; honey-brown translucent except apex cap golden, posteriorly bordered by a dark ring; oval-shaped, densely wrapped by silk, irregular cap border, anterior end (cap) nipple-like. The cocoon was found unattached inside a structure built by the caterpillar using grass leaves and silk (Fig. 12). No trace of a suspending thread was detected.
11 Meteorus orocrambivorus sp. n. cocoon 12 Orocrambus ramosellus caterpillar 13 Orocrambus ramosellus adult 14 Lewis Pass, the type-locality.
(Figs 12 and 13). The information gathered from the type series and additional rearings indicates that Meteorus orocrambivorus is a solitary parasitoid of larval Orocrambus ramosellus, Orocrambus simplex and Merophyas leucaniana. Parasitized Orocrambus have been collected feeding on Festuca novae-zelandiae, Poa cita. Holcus lanatum L., Anthoxantum odoratum L., Agrotis capillaris L., Festuca rubra L. and Rytidosperma setifolium (Hook. f.) Connor & Edgar. Merophyas leucaniana was collected on Festuca novae-zelandiae.
The species name orocrambivorus is a reference to its feeding habit. The stem of the specific epithet refers to the genus name of the host caterpillar, Orocrambus, and the suffix comes from the Latin -vorare meaning “devour.”
The results of a molecular-based phylogenetic analysis carried out by Julia Stigenberg (unpublished data) placed Meteorus orocrambivorus close to Meteorus versicolor Wesmael. Meteorus versicolor belongs to clade IIB proposed by
15 Meteorus orocrambivorus, ventral borders of first tergite almost touching distally 16 Meteorus versicolor, ventral borders of first tergite completely joined along its basal half. White arrows on both pictures indicate the apical section of the structure. Black arrows indicate the most apical point where the ventral borders converge.
Wing reduction as an adaptation to live in concealed, small and close-fitting niches is a compelling hypothesis to explain wing reduction in several species of Doryctinae (
But a possible adaptation to live in cryptic environments does not fully explain the remarkable sexual dimorphism. The common pattern of sexual dimorphism in Meteorus species is: body size and relative eyes size smaller in males than females, relative ocelli size larger in males than females, antennae longer in males than females, in some cases darker body color in males than females, and the obvious absence of ovipositor in males. The morphological deviation in Meteorus orocrambivorus females is so extreme that the initial assignation of females to the genus Meteorus was dependent on the examination of males. A fleeting glimpse of a Meteorus orocrambivorus female in the field could lead to confusion because of its ant-like appearance. The close morphological and behavioral resemblance to ants is called myrmecomorphy, and it is outlined by a set of departures from the common bauplan in those arthropods having it (
We thank Julia Stigenberg for providing results of the DNA analysis. Dr. Zhaojie Zhang of the University of Wyoming Microscopy Core Facility is thanked for his kind assistance and advice with scanning electron microscopy. We are also grateful to the Museum of New Zealand Te Papa Tongarewa and especially to Mr Ricardo Palma for his kindness in allowing access to the museum’s Hymenoptera collection. The auto-montage imaging system was provided by National Science Foundation grant DEB-10-20751. Any opinions, findings, and conclusions expressed are those of the author and do not necessarily reflect the views of the National Science Foundation. CdS was supported by a University of Canterbury Doctoral Scholarship and a Hellaby Trust Fellowship. The research was funded by the Marsden Fund (UOC-0705, grantholder Jason M. Tylianakis) and the Miss E. L. Hellaby Indigenous Grassland Research Trust.