Creagrura Townes, 1971

Saeaeksjaervi, Ilari E., Kaunisto, Kari M., Sharkey, Michael, Stedenfeld, Shelby, Smith, M. Alex, Hallwachs, Winnie & Janzen, Daniel, 2022, Cryptic biodiversity of tropical hesperiid caterpillar-attacking parasitoid wasps: three new species of Creagrura Townes (Hymenoptera, Ichneumonidae, Cremastinae) from Costa Rica and Peru, Biodiversity Data Journal 10, pp. 91486-91486 : 91486

Creagrura Townes, 1971

Creagrura Townes, 1971: 6. Type-species: Creagrura nigripes Townes, by original designation.

Creagrura Creagrura nigripes Townes, 1971

Description

Modified from Gauld (2007).

Moderately large species, mainly yellowish-orange or orange-blackish, variously infuscate dorsally, front wings with a dark spot apically. Fore-wing length 8.0 to 9.8 mm. Clypeus separated from face by a suture. Mandibles with a broad ventral flange. Upper tooth of mandible longer and broader than lower tooth. Palpae formula 5:4. Frons slightly biconcave, polished. Antennae hirsute, flagellomeres infuscate, pedicel and scape variable in colouration. Occipital carina broadly interrupted mediodorsally, laterally strong, joining hypostomal carina at base of mandible. Pronotum unspecialised, with epomia slightly raised parallel to anterior margin, upper end detached and angled towards upper margin of pronotum. Mesoscutum with notauli present, broadly, but shallowly, depressed. Scutellum moderately convex, with strong lateral carinae reaching the posterior end. Mesopleuron smooth, punctuated on lower part. Epicnemial carina complete. Metapleuron punctated, separated from propodeum by a strong pleural carina. Propodeum with anterior and posterior transverse carinae present and complete. Lateral longitudinal carinae of propodeum present or rarely absent. Lateromedian longitudinal carinae present or rarely absent. Area superomedia more or less coffin-shaped or very rarely absent. Lateromedian longitudinal carina forming a V- or Y-shaped area basalis. Legs with tarsal claws small, pectinated to apices. Mid-tibia with two apical spurs. Hind femur smooth, without ventral tooth. Fore-wing with an enclosed oblique areolet. Pterostigma slender, blackish, narrower than first subdiscal cell. Distal abscissa of M complete to wing margin. Hind-wing with distal abscissae of M, Cu1 and 1A spectral distally or otherwise incomplete. Metasoma laterally strongly compressed. First tergite elongate, without glymma, ventral margins enclosing most of the sternite. Second tergite slender, varying in length, with a large thyridium. Laterotergite of the second tergite membranous, pendant. Ovipositor short and stout, orange-brownish in colouration and strongly decurved (hook-shaped), without subapical dorsal notch. Male claspers unspecialised, aedeagus slender, decurved, subapical bristles present.

Diagnosis

Creagrura is easy to distinguish from all other genera of the subfamily Cremastinae by the following set of characters: 1) ovipositor short and strongly down-curved, hook-shaped, 2) scutellum with strong lateral carinae, 3) mandible with broad ventral flange, 4) first tergite of metasoma ventrally almost completely enclosing the sternite and 5) second tergite of metasoma with a large thyridium.

Biology

In ACG, the two new species of Creagrura are middle to late instar koinobiont endoparasitoids of caterpillars that are diurnally concealed in longitudinally folded grass, sedge, ginger, palm or marantaceous leaves ( Gauld 2007, DJ, WH, personal observation). However, this is a false impression created by the foraging habits of insect collectors. The caterpillars hide all day in a folded/rolled leaf of their food plant, but venture forth to eat that same and adjacent leaves at night. Since the wasps display all the yellow-orange colour and the behaviour of noctural adult Darwin wasps (Obs.: they do not have enlarged ocelli), we infer that the wasps find and oviposit in the caterpillar when it is exposed at night, rather than when it is concealed in a tight leaf tube during daylight hours. This hypothesis is further supported by the fact that specimens of Creagrura are rarely collected by Malaise trapping (see above) which is the standard tropical sampling method for diurnal Darwin wasps.

Creagrura alejandromasisi sp. n. (BIN AAA2329) is known only from ACG, where it is exclusively a specialist at parasiting the mid- to last instars of medium-sized (2-4 cm) Hesperiinae ( Hesperiidae ) caterpillars feeding on and day-time sequestering amongst the mature leaves of broad-leafed rain forest perenial monocots ( Costaceae , Marantaceae , Cannaceae ) in mostly insolated and full shade microhabitats 90-900 m elevation. It does not extend into adjacent ACG dry forest, as does C. rogerblancoi sp. n., which feeds on Poaceae , Arecaceae and Cyperaceae in both sun and shady microhabitats. It may be common elsewhere in Costa Rica, but not collected, simply because, in decades of Malaise trapping its ACG microhabitats, it has never been caught by a Malaise-trap. While there are many other genera and species of hesperiine and non-hesperiine caterpillars living and feeding in these microhabitats, C. alejandromasisi sp. n. is notable for parasitising only the following species of caterpillars (n = 634 of 155,932 ACG Hesperiidae wild caterpillars reared between 1978 and 2021), almost never a palm-eater, grass-eater or sedge-eater and 91% of the time reared from one of eight species of Saliana ( Hesperiidae ): (http://janzen.sas.upenn.edu/caterpillars/database.lasso): Calpodes ethlius (5), Cynea Burns02 (1), Cynea irma (2), Cynea megalops (1), Decinea decinea derisor (1), Parphora decora (1), Rhinthon molion (1), Rhinthon osca (29), Saliana antoninus (70), Saliana Burns03 (10), Saliana Burns06 (1), Saliana esperi (379), Saliana fusta (15), Saliana longirostris (1), Saliana placens (3), Saliana severus (85) and Talides Burns04 (1). These caterpillars show a wide range of body types and colours, in contrast to those parasitised by C. rogerblancoi . An image of the solitary wasp cocoon with caterpillar cadaver is available at http://janzen.sas.upenn.edu/Wadults/searchplaycat4apr15.lasso?Voucher==05-SRNP-43145&-search and images of all of these species of caterpillars are available at htpp://janzen.sas.upenn.edu.

To date, C. alejandromasisi sp. n. has no suggestion of being attacked by any of the many tens of species of ACG common hyperparasitoids (e.g. Mesochorus , Ichneumonidae ; Perilampus , Perilampidae , Chalcididae ). Its host caterpillars are also attacked by a small array of other species of parasitoids, but those will be treated in other more cross-taxon ecological publications.

Creagrura rogerblancoi sp. n. (BIN AAA5105) has a caterpillar biology quite similar to that of Creagrura alejandromasisi sp. n. described above, except for its species of food plants and caterpillars, lesser sample size and a slight difference in sympatric microecosystems. While there are many other genera and species of hesperiine and non-hesperiine caterpillars living and feeding in its microhabitats, C. rogerblancoi sp. n. is notable for parasitising only the caterpillars of Orses cynisca (257), rarely three genera of grass-eating hesperiinae Hesperiidae and six species of Perichares (37) as grass-eating and understorey palm-eating caterpillars (306 of 155,932 ACG Hesperiidae wild caterpillars reared between 1978 and 2021). Orses cynisca is only feeding on leaves of four species of Cyperaceae and 34 species of Poaceae and the Perichares feed only on grasses and understorey palm leaves. Creagrura alejandromasisi never parasitises Perichares caterpillars feeding on palms or Orses cynisca , whatever plant species it is eating. Equally, C. rogerblancoi never attacks Saliana caterpillars, wherever they are feeding. As a result of their parasitisation of Perichares feeding on leaves of deeply shaded rainforest understorey palms, C. rogerblancoi wasps are more often reared from shady portions of the microhabitat than are C. alejandromasisi , but because the parasite-host interaction presumably takes place at night, this is probably just a serendipitous outcome of the species of host caterpillars and their food preferences. The caterpillars of the four species of Perichares studied intensively (Burns et al. 2008) are nearly identical in superficial appearance, but subtly different in their morphology to each other and similar to the caterpillars of Orses cysnisca (http://janzen.sas.upenn.edu/caterpillars/database.lasso). C. rogerblancoi is common throughout ACG lowland rainforest, but also extends into ACG lowland dry forest (parasitising hesperiine caterpillars eating grasses and sedges).

Taxon discussion

Creagrura Townes has been viewed as a monotypic Neotropical genus ranging from Central to South America for 50 years. Small morphological intraspecific variation previously led to the recognition of only one species, C. nigripes Townes 1971 ( Townes 1971, Gauld 2007). Gauld (2007) stated that it is widespread throughout the Neotropics, but prior to more than a superficial understanding of ACG specimens and their DNA barcodes that emerged in 2004. This new understanding was not available to Gauld in 2007 because the indicative barcode data was still embedded in the gradually accumulating databases of the ACG inventory.

After studying a large amount of new genetic, morphological and biological data, it is now clear that there is more than one species in the genus and all previous descriptions of morphology and geographic ranges are pools of multiple species not individually recognised. All of the hundreds of the two new species, reared in the ACG biodiversity inventory, were misidentified as Creagrura nigripes . There is no evidence that C. nigripes even occurs in Costa Rica or further north. Neither of the two new Costa Rican species have ever been captured in a Malaise trap, despite decades of Malaise trapping ACG forests where the two new species are very common. This result suggests that standard collections of tropical Hymenoptera are likely to not obtain Creagrura , despite its being a common wasp parasitising its common host species of Hesperiidae caterpillars. This note is further supported by our data from South America. Despite of collecting> 250 MTMs (Malaise trap months) in Peru ( Gomez et al. 2018), we have found only a very few Creagrura specimens from these samples.

The mandibular flange and lateral carinae of the scutellum are key identifying characters of Creagrura , but they can also be found in some other Neotropical cremastines. Species of Eiphosoma Cresson exhibit this flange and one, apparently undescribed, Amazonian species has been found to possess a raised, lateral carina on the scutellum (Stedenfeld and Sääksjärvi, unpublished data).