Nine new species of Itaplectops (Diptera: Tachinidae) reared from caterpillars in Area de Conservación Guanacaste, northwestern Costa Rica, with a key to Itaplectops species

AJ Fleming; D. Monty Wood; M. Alex Smith; Daniel Janzen; Winnie Hallwachs

doi:10.3897/BDJ.3.e4596

Biodiversity Data Journal : Taxonomic paper

PDF

Taxonomic paper

Nine new species of Itaplectops (Diptera: Tachinidae) reared from caterpillars in Area de Conservación Guanacaste, northwestern Costa Rica, with a key to Itaplectops species

AJ Fleming^‡, D. Monty Wood^‡, M. Alex Smith^§, Daniel H. Janzen^|, Winnie Hallwachs^|

‡ Agriculture Agri-Food Canada, Ottawa, Canada

§ Department of Integrative Biology, Guelph, Canada

| University of Pennsylvania, Philadelphia, United States of America

Corresponding author:

Academic editor: Daniel Whitmore

Received: 26 Jan 2015 | Accepted: 20 Dec 2015 | Published: 23 Dec 2015

This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Citation: Fleming A, Wood D, Smith M, Janzen D, Hallwachs W (2015) Nine new species of Itaplectops (Diptera: Tachinidae) reared from caterpillars in Area de Conservación Guanacaste, northwestern Costa Rica, with a key to Itaplectops species. Biodiversity Data Journal 3: e4596. https://doi.org/10.3897/BDJ.3.e4596

ZooBank: urn:lsid:zoobank.org:pub:B1A3D7CB-6BB3-4091-B625-A555E059EEDF

Abstract

Nine new species of Itaplectops Townsend (Diptera: Tachinidae) are described from Area de Conservación Guanacaste (ACG), northwestern Costa Rica. All specimens have been reared from various species of ACG caterpillars in the families Limacodidae and Dalceridae. By combining morphological, photographic, and genetic barcode data we provide clear yet concise descriptions. The following nine new species are described in the genus Itaplectops: Itaplectops akselpalolai, Itaplectops anikenpalolae, Itaplectops argentifrons, Itaplectops aurifrons, Itaplectops ericpalolai, Itaplectops griseobasis, Itaplectops omissus, Itaplectops shellymcsweeneyae, Itaplectops tristanpalolai. We move Itaplectops to the tribe Uramyini from its original placement within the Blondeliini, and we discuss its systematic placement. We also provide a key differentiating the, genera of the tribe Uramyini as well as the known species of Itaplectops.

Keywords

tropical rain forest, tropical dry forest, cloud forest, parasitoid fly, host-specificity, caterpillar, Uramyini

Introduction

The tachinid genus Itaplectops Townsend is a small New World genus, previously known only from the type species (Guimarães 1971) and one previously unidentified species from Area de Conservación Guanacaste (ACG) in northwestern Costa Rica mentioned in Wood and Zumbado (2010) which is now described here. The genus was erected for a single female specimen obtained in Cantareira, Brasil, in 1927, described as Itaplectops antennalis Townsend, 1927. Here we describe nine new species from the genus Itaplectops, reared from wild caterpillars collected in ACG (Janzen et al. 2009).

Guimarães (1971) in his Neotropical catalog, placed Itaplectops Townsend in the tribe Blondeliini; however, according to the tribal concept set out by Wood (1985) the morphological characters of Itaplectops would exclude it from this tribe. Guimarães (1980) published the last major systematic work on the tribe Uramyini. In it he provided a diagnosis of the tribe and recognized only two valid genera: Uramya Robineau-Desvoidy 1830 and Thelairaporia Guimarães, 1980. We also discuss the inclusion of the genus Itaplectops Townsend in the tribe Uramyini.

All species described as new herein are based on differences in external morphology, male terminalia, and COI sequences (coxI or cytochrome oxidase 1, a.k.a. DNA barcodes). Our present study focuses on northwestern Costa Rica, and these nine new species are by no means considered by us to be representative of the whole Itaplectops diversity of the region.

Materials and methods

Abbreviations of depositories

CNC Canadian National Collection of Insects, Arachnids and Nematodes, Ottawa, Canada

USNM U.S. National Museum of Natural History, Washington, D.C., USA

INBio Instituto Nacional de Biodiversidad, Santo Domingo de Heredia, Costa Rica

Geographic area of the study and rearing intensity

The flies described in this paper were collected as part of a 35+ year–old ongoing inventory of the caterpillars, their food plants and their parasitoids, found within the 125,000+ ha terrestrial portion of Area de Conservación Guanacaste (ACG) in northwestern Costa Rica (Fernandez-Triana et al. 2014, Fleming et al. 2014a, Janzen and Hallwachs 2011, Janzen et al. 2009, Rodriguez et al. 2012, Smith et al. 2012, Smith et al. 2007, Smith et al. 2006, Smith et al. 2008).The methods employed for rearing the caterpillar parasitoids are illustrated at http://janzen.bio.upenn.edu/caterpillars/methodology/how/parasitoid_husbandry.htm. In brief, caterpillars of all instars (and sometimes pupae) are found in the wild by a wide variety of search methods, and reared in captivity on the food plant species on which they were found, until they produce an adult parasitoid or die of other causes.

It should be noted that this inventory searches some vegetation types and vertical strata much more thoroughly than others. This bias is due to the methods employed for collecting of specimens, which rely solely on those animals within reach of the collectors, up to 3m above the ground. Recent comparisons of reared species of parasitoids with those collected by net or Malaise traps demonstrate that, to date, the estimated 1100+ species of tachinid flies reared by the caterpillar inventory represent less than half the species of caterpillar-parasitizing Tachinidae present in ACG. The largest unsampled habitat is the foliage of the canopy at approximately 3–4m above the ground.

This paper on Itaplectops is part of a larger effort to describe the new species reared during the ACG inventory (Fleming et al. 2014a, Fleming et al. 2014b, Fleming et al. 2015). This series of papers will represent the baseline for later, more detailed ecological and behavioral accounts and studies that will extend across ACG ecological groups, whole ecosystems, and taxonomic assemblages much larger than a genus.

Dissections and imaging

Habitus and terminalia photographs were taken using the methods outlined in Fleming et al. (2014a). Raw image files were first processed with Adobe Photoshop CS6, then digitally stacked to produce a final composite image using Zerene Stacker Software v1.04. Whenever possible, the images provided are of the holotype; however, in cases where a paratype was photographed this is mentioned in the image caption.

Adult flies were dissected following standard practice (O’Hara 1983). Preparations were mounted on a depression slide in a small quantity of Rexall hand sanitizer gel (NPN# 80007138) (Fleming et al. 2014a). After mounting and photographing, the terminalia were rinsed in a small quantity of pure distilled water before being replaced in a glycerine-filled microvial.

The terminology used for structures of the terminalia (which refers here only to the sclerotized parts of the genitalia, and not to the soft internal structures) and other body parts follows Cumming and Wood (2009).The frontal vitta and fronto-orbital plate were measured at the widest point of the frontal vitta, directly above the lunule.

Voucher specimen management

All caterpillars reared from the ACG efforts receive a unique voucher code in the format yy–SRNP–xxxxx. Any parasitoid emerging from a caterpillar receives the same voucher code. When the parasitoid is later dealt with individually, it receives a second voucher code unique to it, in the format DHJPARxxxxxxx. The voucher codes and data assigned to both host and emerged parasitoids are available at http://janzen.bio.upenn.edu/caterpillars/database.lasso. To date, all DHJPARxxxxxxx-coded tachinids have had one leg removed for attempted DNA barcoding at the Biodiversity Institute of Ontario (BIO), University of Guelph, with all collateral data and all successful barcodes permanently and publicly deposited in the Barcode of Life Data System (BOLD, www.boldsystems.org) (Ratnasingham and Hebert 2007), and later migrated to GenBank as well.

Inventoried Tachinidae were collected under Costa Rican government research permits granted to DHJ since 1978, and likewise exported under permit by DHJ from Costa Rica to Philadelphia, and from there to their final depository in the CNC. Tachinid identifications for the inventory were coordinated by DHJ with help from: AJF and DMW (morphology), MAS (barcoding), and DHJ and WH (correlation with host species). Dates of capture of each reared flies in the inventory are the dates of eclosion of the fly, not the date of capture of the caterpillar. The fly eclosion date is much more representative of the time when that fly species is on the wing, than is the date of capture of the caterpillar or, (rarely) the finding of the parasitized pupa. The collector listed is the parataxonomist who found the caterpillar rather than the person who retrieved the newly eclosed fly from its rearing bag or bottle. Life history, biology and parasitization frequencies by these flies will be the detailed subject of later papers.

The five patronyms proposed here are in honor of the Palola-McSweeney family of Vermont, USA, in recognition of their essential role in the development of the Guanacaste Dry Forest Conservation Fund (http://www.gdfcf.org) in support of Area de Conservación Guanacaste (http://www.acguanacaste.ac.cr).

The holotypes of the new species have been deposited in CNC.

DNA barcoding

DNA barcodes (the standard 5’ region of the mitochondrial cytochrome c oxidase I (COI) gene) for all ACG inventory specimens were obtained using DNA extractions made from single legs using a glass fiber protocol (Ivanova et al. 2006). Total genomic DNA was re-suspended in 30μl of dH₂O, and a 658-bp region near the 5’ terminus of the COI gene was amplified using standard primers (LepF1–LepR1), following established protocols (Smith et al. 2006, Smith et al. 2007, Smith et al. 2008). All information for the sequences associated with each individual specimen (including GenBank and BOLD accession numbers) can be retrieved from the Barcode of Life Data System (BOLD) (Ratnasingham and Hebert 2007) via the publicly available dataset dx.doi.org/10.5883/DS-ASITAPLE. A neighbor–joining (NJ) tree (Saitou and Nei 1987) for all Itaplectops reared and DNA-barcoded within the inventory through 2015 is included as Supplementary material in this paper (Suppl. material 1).

Species previously included in Itaplectops

Itaplectops Townsend 1927: 265. Type species: Itaplectops antennalis Townsend 1927, by original designation.

Itaplectops antennalis Townsend 1927: 321; holotype female (USNM) [examined by DMW]. Type locality: Brazil, São Paulo, São Paulo, Cantareira. Type label: “Tremembe/23.X.//Type//Itaplectops/ antennalis /TT. ♀/ Det CHTT”.

Note: Townsend's original locality label displays the place name: "Tremembe" (sic.), however, the original publication states the type locality as Cantareira. Townsend created some confusion with the inconsistent use of the type locality 'Tremembé da Cantareira' referring to what was at his time was a railway station on the northern edge of São Paulo. Among the names he used to refer to this locality were: 'Cantareira', 'Tremembé', and 'S. Cantareira'. Tremembé da Cantareira is situated in what is now called Bairro do Tremembé, on the northern edge of the district of Tremembé. Serra do Cantareira is now used to refer to the state park that surrounds the area of the old Tremembé railway station and is likely to be the area to which Townsend was referring.

Diagnosis of genus Itaplectops

Males and females ranging in total body length from 4 to 7mm.

Head: as wide as thorax when viewed dorsally; facial margin not visible in profile; tawny to brown frontal vitta; eyes densely haired; ocellar bristles small or absent; palpus and proboscis orange; antenna ranging from orange to dark brown, arista bare and ranging in color from orange to entirely dark brown; fronto-orbital plate silvery to very slightly gold tinged; both males and females possessing proclinate orbital bristles (these on rare occasions absent or reduced in males); parafacial and gena silvery to slightly brassy in color; parafacial bare to sparsely haired; facial ridge ranging from bare to bristled along half of its length; gena 1/4 height of eye; vibrissa strongly developed, level or almost level with facial margin. Thorax: thorax and scutellum light gray tomentose throughout; 4 thoracic vittae almost invisible, only slightly darker than the gray thorax, in most cases only visible under certain angles of light; prescutum 1/2–3/4 length of scutum; 3 postsutural dorsocentral bristles; 2–3 postsutural supra-alar bristles; when 3 are present then first postsutural supra-alar greatly reduced; scutellum with at least two pairs of divergent subapical bristles and one pair of crossed apicals; scutellum with 0 to 2 pairs of discal bristles; 2 katepisternal bristles, anteriormost reduced in size; legs varying from yellowish to entirely black and densely haired; wings ranging from smoky yellow to smoky gray, slightly darker along costal margin; costal spine absent; wing veins bare except for the presence of 2–5 small setulae at the base of R₄₊₅; calypters translucent to clear with dense short hairs along their margins. Abdomen: shiny black with a varying degree of silver tomentosity along upper segmental margins; in most cases the abdominal tergites lack median discal bristles, however, when present, they only occur up to T3; mid-dorsal depression extending 1/2–2/3 distance to margin of T1+2. Male terminalia: cercus digitiform, elongate and minorly clubbed at apex, apical 1/3 tapering rapidly down to 1/5 at its widest point, convex when viewed laterally, not fused medially, apex of cerci ranging from very slightly divided to touching when viewed dorsally; surstylus from 7/10 to 9/10 the length of the cercus, from slightly inwardly bent apically to straight, bearing a slight hook at tip, visible in profile, surstylus ranging from bare to densely bristled. Epandrium hirsute, with two apically crossed bristles. Sternite 5 uniform across all species, lobe of sternite 5 with rough serrated inner edge, lobe covered in dense stout bristles. L-shaped hinged phallus, with the end of the basiphallus overlapping the base of the distiphallus.

Discussion of tribal placement

Guimarães (1971) placed the genus Itaplectops in the tribe Blondeliini in the subfamily Exoristinae. Current evidence indicates that Itaplectops belongs in the tribe Uramyini of the subfamily Dexiinae, which to date included only Thelairaporia and Uramya. The Dexiinae are particularly easy to recognize due to the presence of a shared common character, namely a hinge in the phallus, accompanied with a close association of the postgonites with the base of the phallus (Wood and Zumbado 2010). Guimarães (1980) provided a diagnosis of the tribe Uramyini. He described it as a New World tribe, particularly well represented in the Neotropics, parasitizing caterpillars within the families Arctiidae (now Arctiinae in the Erebidae), Limacodidae, Megalopygidae, Lasiocampidae, and Dalceridae (Arnaud 1978, Guimarães 1980, Wood and Zumbado 2010). Guimarães (1980) provided a strong definition of the tribe based on the following diagnostic characters: general body plan slightly to strongly elongate, with body mainly black to dark brown; eyes densely haired; facial margin flat, not visible in profile; lowermost frontal bristles not extending below level of pedicel; facial ridge ranging from bare to bristled on lower half; first flagellomere elongated, nearly reaching lower facial margin; vibrissa strongly developed, almost level with lower facial margin; gena approximately 1/4 of eye height; genal dilation not well developed; prosternum and propleura devoid of strong bristles; postpronotum with four to five strong bristles; prescutum almost as long as scutum (between 2/3 and 3/4 length of scutum in Itaplectops); 3 postsutural dorsocentrals; 3 postsutural supra-alars (anteriormost pair weak or absent in some Itaplectops); wings elongate with a very faint tinge around the costa (in some species of Uramya the wings can be adorned with elaborate markings); costal spine absent; all tergites bearing median marginal bristles, abdominal discal bristles present, on T3 to T5, and sometimes on T1+2 (except in Itaplectops, which can have more varied abdominal chaetotaxy, some species lacking median marginals on T1+2 and T3, and ranging from having no discal bristles to discal bristles being present only on T1+2 and T3). Male genitalia with an L-shaped phallus, end of basiphallus prolonged over the base of the distiphallus, and a long anteriorly curved postgonite. Other similarities shared by members of the tribe, not mentioned by Guimarães (1980), include: the similarity in the arrangement of the lappets of the posterior spiracle – in all three genera the lappets of the posterior thoracic spiracle are almost equal in size, giving the spiracular opening an almost "V" shape – and a bare prosternum; in Uramya the prosternum appears pollinose yet devoid of bristles.

The male terminalia, which are sometimes useful in defining the subfamilies or tribes of the Tachinidae, appear as a major defining character of the tribe Uramyini. In the male terminalia, Itaplectops shares the synapomorphy of the L-shaped hinged phallus, with the end of the basiphallus overlapping the base of the distiphallus, traits common to the rest of the tribe. These structures are stereotypical of the terminalia in the subfamily Dexiinae and are consistent with Guimarães’s diagnosis of the male terminalia in the Uramyini (Uramya and Thelairaporia).

Chaetotaxy, while extremely useful, is not the only important character set defining a genus (Wood 1985). Itaplectops differs somewhat from Guimarães's concept of Uramyini by the presence of 2 rather than 3 katepisternals, and the reduction to sometimes apparent absence of the anterior postsutural supra-alar bristle. Our results suggest a close relationship between Itaplectops and Thelairaporia, which was hinted at by Wood and Zumbado (2010). Itaplectops can be differentiated from Thelairaporia by the presence of only 2 katepisternal bristles, the presence of discals on the scutellum, and the absence of discals on T4. Genera are commonly thought of as neatly categorized assemblages of species. This idea, however, fails to acknowledge the fact that evolution is a fluid matrix in which species are constantly being created and destroyed. The proximity of these two genera may one day be clarified as existing somewhere along this sliding scale idea of evolution.

Barcoding Results

The DNA barcode sequences recovered from ACG Itaplectops display the characteristic strong AT bias of insect mitochondrial DNA (mean percent GC content 30.82, SE 0.17) and no insertions or deletions. Within-species variation was low (mean distance of 0.27%) compared to between-species variation (mean distance 8.06%). All values of DNA barcode variation were calculated within BOLD and can be re-calculated in the future as more specimens are recovered from the ACG inventory and added to the DNA library. Fig. 1 is a neighbor–joining tree for the Itaplectops holotypes reared and DNA-barcoded by this inventory to date.

Figure 1.

Neighbor-Joining (NJ – Saitou and Nei 1987) tree based on Kimura 2-parameter distances (K2P – Kimura 1980) made using MEGA6 (Tamura et al. 2013) for a single specimen from each of the nine species of Itaplectops in ACG. Tip labels include species name, specimen accession number, host species, host family and the lateral image of a male.

Taxon treatments

Itaplectops akselpalolai Fleming & Wood, 2014, sp. n.

ZooBank urn:lsid:zoobank.org:act:067C8099-35A3-42FA-A97C-A4527532CF5B

Material Download as CSV

Holotype:

scientificName:
Itaplectops akselpalolai
; phylum:
Arthropoda
; class:
Insecta
; order:
Diptera
; family:
Tachinidae
; genus:
Itaplectops
; specificEpithet:
akselpalolai
; scientificNameAuthorship:
Fleming & Wood
; continent:
Central America
; country:
Costa Rica
; countryCode:
CR
; stateProvince:
Guanacaste
; county:
Area de Conservacion Guanacaste
; locality:
Sector Rincon Rain Forest
; verbatimLocality:
Palomo
; verbatimElevation:
96
; verbatimLatitude:
10.96187
; verbatimLongitude:
-85.28045
; verbatimCoordinateSystem:
Decimal
; decimalLatitude:
10.96187
; decimalLongitude:
-85.28045
; samplingProtocol:
reared from caterpillar of Natada michorta (Limacodidae)
; verbatimEventDate:
26-Sep-2013
; individualID:
DHJPAR0053409
; individualCount:
1
; sex:
M
; lifeStage:
adult
; preparations:
pinned
; catalogNumber:
DHJPAR0053409
; occurrenceDetails:
http://janzen.sas.upenn.edu
; recordedBy:
D.H. Janzen & W. Hallwachs, Keiner Aragon
; otherCatalogNumbers:
ASHYM2763-13, 13-SRNP-79398
; identifiedBy:
AJ Fleming
; dateIdentified:
2014
; language:
en
; institutionCode:
CNC
; collectionCode:
Insects
; basisOfRecord:
Pinned Specimen

Description

Male

Length: 6mm.

Head (Fig. 2c): proclinate orbital bristles absent; first flagellomere entirely dark, brown to brownish orange over at least 1/2 of its surface; arista dark brown over 1/2 of its length, bright orange basally, with gradual taper; first flagellomere slightly shorter than facial margin by less than half the length of the pedicel; ocellar bristles well developed, at least the length of the pedicel, and arising behind anterior ocellus; ocellar triangle bare; frontal vitta approximately 4x as wide as fronto-orbital plate; facial ridge bearing at least 3 stout supravibrissal bristles; fronto-orbital plate slightly silver; parafacial bare and entirely silver; fronto-orbital plate bare.

Figure 2.

Itaplectops akselpalolai sp. nov. Holotype male; voucher code: DHJPAR0053409; genitalic dissection number: 13-SRNP-79398.

a: dorsal habitus
b: lateral habitus
c: frontal view of head
d: dorsal view of terminalia
e: lateral view of terminalia

Thorax (Fig. 2a, b): three postsutural supra-alar bristles; katepisternum with 2 bristles, anteriormost reduced in size and arising directly below to slightly anterior to suture; apical scutellar bristles short, up to 1/2 the length of subapical scutellars; subapical scutellar bristles strongly divergent; scutellum with no apparent discal bristles.

Wings (Fig. 2a): smoky yellow.

Legs (Fig. 2b): ground color of at least 1/2 of femur yellow, tibia yellow, and tarsi yellow (although these may appear dark due to hirsuteness); dorso-ventral margin of hind tarsi with yellow tufts of bristles apically.

Abdomen (Fig. 2a, b): T1+2 with mid-dorsal depression extending 2/3 along its length, but not reaching tergal margin; silver tomentosity on margins of abdominal segments T3 and T4 only visible under certain angles of light, with these bands not extending beyond 1/3 of tergal surface; median marginal bristles present on T1+2, T3, T4 and T5; reduced discal bristles present on T3, these arising within the silver tomentose band along the tergal margin, sometimes appearing like thickened abdominal hairs.

Terminalia (Fig. 2d, e): both cerci tightly juxtaposed when viewed dorsally. Cercus haired along basal 2/3^rds; appearing convex when viewed laterally with a very slight thickening apically. Surstylus 9/10 as long as cercus, when viewed dorsally outwardly convex at its center, appearing bowed with a very slight acute downward bend apically, with a very slight hook at its tip. Cercus densely bristled along its entire length. Phallus 5x as long as cercus, straight and downwardly curved.

Female: unknown at this time.

Diagnosis

Itaplectops akselpalolai can be distinguished by the following combination of traits: proclinate orbital bristles absent in males; first flagellomere dark brown/black over 1/2 its surface; 3 postsutural supra-alar bristles; median marginal bristles present on T1+2, T3, T4 and T5; discal bristles present at least on T3; silver tomentosity on margins of abdominal segments T1+2, T3, and T4, confined to anterior 1/3 of tergite. It can be distinguished from its most similar congener, Itaplectops griseobasis, following couplet 9 in the key to Itaplectops (below).

Etymology

Itaplectops akselpalolai is named in honor of Aksel Palola of Vermont, USA, a supporter of Eric Palola, Shelly McSweeney, Aniken Palola and Tristan Palola, and therefore of GDFCF and ACG.

Distribution

Costa Rica, ACG, Prov. Alajuela and Guanacaste, rain forest.

Ecology

Hosts:

Reared from caterpillars of Limacodidae, Natada Walker spp.