Lytopylus Förster (Hymenoptera, Braconidae, Agathidinae) species from Costa Rica, with an emphasis on specimens reared from caterpillars in Area de Conservación Guanacaste

Michael J Sharkey; Stephanie Clutts; Erika M Tucker; Daniel Janzen; Winnie Hallwachs; Tanya Dapkey; M Alex Smith

doi:10.3897/zookeys.130.1569

. 2011 Sep 24;(130):379–419. doi: 10.3897/zookeys.130.1569

Lytopylus Förster (Hymenoptera, Braconidae, Agathidinae) species from Costa Rica, with an emphasis on specimens reared from caterpillars in Area de Conservación Guanacaste

Michael J Sharkey ¹, Stephanie Clutts ², Erika M Tucker ³, Daniel Janzen ³, Winnie Hallwachs ³, Tanya Dapkey ³, M Alex Smith ³

PMCID: PMC3252762 PMID: 22259290

Abstract Abstract

Twelve species of Costa Rican Lytopylus are treated; these include all species reared from Lepidoptera caterpillars in Area de Conservación Guanacaste, Costa Rica, over 32 years of caterpillar inventory, as well as two species recorded in the literature as occurring in Costa Rica. Ten new species are described, i.e., Lytopylus bradzlotnicki, Lytopylus colleenhitchcockae, Lytopylus gregburtoni, Lytopylus jessicadimauroae, Lytopylus jessiehillae, Lytopylus mingfangi, Lytopylus rebeccashapleyae, Lytopylus robpringlei, Lytopylus sandraberriosae, Lytopylus vaughntani. The following species are transferred to Lytopylus: Metriosoma flavicalcar Enderlein 1920 to Lytopylus flavicalcar comb. n.; Bassus macadamiae Briceño and Sharkey 2000 to Lytopylus macadamiae comb. n.; Metriosoma bicarinatum Enderlein 1920 to Lytopylus bicarinatum comb. n.; Metriosoma brasiliense Enderlein 1920 to Lytopylus brasiliense comb. n.; Bassus tayrona Campos 2007 to Lytopylus tayrona comb. n.; Microdus femoratus Cameron 1887 to Lytopylus femoratus comb. n.; Microdus melanocephalus Cameron 1887 to Lytopylus melanocephalus comb. n.; Bassus pastranai Blanchard 1952 to Lytopylus pastranai comb. n.; Agathis nigrobalteata Cameron 1911 to Lytopylus nigrobalteatus comb. n. Two keys to species of Lytopylus are presented, one interactive and the other static.

Keywords: parasitoids, biology, endoparasitoids, koinobiont, Lepidoptera

Introduction

This is the first of a series of articles to revise the species of Agathidinae reared from lepidopteran caterpillars as part of the inventory of the caterpillars and their parasitoids of Area de Conservación Guanacaste (ACG), northwestern Costa Rica (http://janzen.sas.upenn.edu; http://www.acguanacaste.ac.cr; Janzen et al. 2009). It includes keys, in traditional and interactive formats, to the reared species of Lytopylus Förster and to the two species of Lytopylus previously recorded from Costa Rica. This is not meant to be a comprehensive treatment of the Costa Rican fauna of Lytopylus. A conservative estimate, based on extensive collections at INBio, the Universidad de Costa Rica, and the University of Kentucky, is that there are a minimum of 50 species occurring in the country. Here we treat only 12.

Lytopylus, though proposed in 1862, has spent most of its existence as a junior synonym of Bassus Fabricius, Microdus Nees, and Agathis Latreille. Sharkey et al. (2009) removed it from synonymy in their revision of the Oriental genera of Agathidinae. New World members of the genus may be distinguished from other agathidines by the sculpture of the third metasomal median tergite and by the structure of the propodeal foramen. See the first couplet of the key included in this publication for specifics. The sistergroup to Lytopylus is Braunsia Kriechbaumer which is restricted to the Old World and is mostly tropical or subtropical (Sharkey et al. 2006).

The source files for the keys, descriptions, illustrations, DNA sequence and distributional data are all freely available to future researchers who may wish to build on this beginning. The detailed specimen records are available by search of the individual specimen DHJPARxxxxxxx voucher codes at http://janzen.bio.upenn.edu/caterpillars/database.lasso. DNA trace files and primer information are available through the Barcode of Life Datasystem (BOLD) [Ratnasingham and Hebert 2007] at http://www.boldsystems.org.

Methods

Phenetic and phylogenetic trees, using 658 base pairs of cytochrome c oxidase (COI) data, were constructed using neighbor-joining (NJ), maximum parsimony (MP) and Bayesian methods. MP was performed using TNT (Goloboff et al. 2008). A traditional search with 100 random addition sequences followed by branch-swapping, saving 100 trees per replication, was performed. 1000 bootstrap replications were used to estimate branch reliability. The Bayesian analysis was performed using MrBayes v3.1.2 (Ronquist and Huelsenbeck 2003). Best-fitting DNA substitution models were determined using MrModeltest2.2 (Nylander 2004). The general time reversible model of evolution with a parameter for invariant sites and rate heterogeneity modeled under a gamma distribution (GTR+I+G) was determined as the best-fitting model.

The Bayesian analysis consisted of two independent Bayesian MCMC runs initiated from different random starting trees. The analysis ran for 2,000,000 generations, reaching a topological similarity criterion of 0.01; trees were sampled every 500 generations. 25% of the trees from each run were removed as burn-in upon topological convergence.

The NJ tree was produced from PAUP* (Swofford 2002) using default settings.

Sequence data, trace files, and field data are available on BOLD (www.barcodinglife.org). Additional collection information is deposited at http://janzen.sas.upenn.edu, and all sequences have been deposited in the GenBank database.

The dichotomous key, descriptions, and the interactive key (Appendices 1–3) were generated using DELTA Editor Dallwitz et al. (1999), DELTA Dallwitz et al. (1993), and Intkey Dallwitz et al. (1995).

This set of 10 species of ACG Lytopylus, represented by 76 specimens, is the yield from rearing 498,000+ wild-caught caterpillars of about 6,000 species from ACG dry forest, cloud forest, and rain forest, and a variety of intergrades, over 32 years, beginning 1978 (Janzen et al. 2009). At least 90% of these caterpillars were, in some instar, large enough to host a larva of Lytopylus. The names of the caterpillars, from which the degree of host-specificity mentioned below is determined, is the collective contribution of more than 100 taxonomists and parataxonomists working with both caterpillar morphology and food plant biology, and correlated adult morphology; additionally, nearly all of the caterpillar species have now had their adults DNA-barcoded as yet another check on identification (Janzen et al. 2009, 2011).

Abbreviations and codes.There are numerous codes in the text. Codes beginning with an “H” and followed by numbers are unique identifiers used for specimens in the Sharkey lab at the University of Kentucky, and in the specimen database (http://sharkeylab.org/taxabank/home.php), e.g., H6408. Codes beginning with DHJPAR, e.g., DHJPAR0036705, are used by Janzen as unique identifiers for the parasitoids reared by the ACG caterpillar inventory. Some of the Lepidoptera hosts are incompletely identified; however, they also have unique names such as Desmia Solis19 (which is an interim name for Desmia species 19 as determined by M. Alma Solis of the USDA Systematic Entomology Laboratory, Washington, D.C.). These names will be updated in the Janzen database (http://janzen.sas.upenn.edu/caterpillars/database.lasso) when the species is baptized with a formal scientific name, but the interim name, in this case Desmia Solis19, will remain searchable in that database. Host caterpillars are uniquely identified by their own voucher code system, which is recognizable by YY-SRNP-XXXXX where “YY” is the two digit year and “XXXXX” is a unique number within that year. DNA barcodes associated with each specimen via the DHJPAR code also each have a searchable accession on BOLD (e.g. ASBC979-07 for DHJPAR0021167).

Abbreviations used for specimen depositories are as follows:

AEI

HIC

INBio

Results

Phylogeny and Biology: Lytopylus is an unusual genus of Agathidinae in that it has a cosmopolitan distribution and a wide range of host higher taxa. Most genera of Agathidinae found in the neotropics are restricted to the New World. When there are exceptions to this rule, they are in the form of Holarctic genera that appear to have dispersed into cool, high altitude areas in the northern neotropics, e.g., Agathis, which is found at high altitudes in Costa Rica (Sharkey, unpublished). Most genera of Agathidinae also seem to be restricted to one or a few closely-related families of Lepidoptera; however, the collective set of Lytopylus species attack a wide range of host families. Even within the small sample of ten reared species of Lytopylus represented here, five host families are attacked, i.e., Crambidae, Elachistidae, Pyralidae, Thyrididae, and Tortricidae. However, all of these are leaf-rolling and leaf-tying small caterpillars. Lytopylus are conspicuous in not using species of caterpillars that feed exposed on leaf surfaces (e.g., butterflies and macro-moths), and in not using large caterpillars. However, their absence from leaf-nest-occupying Hesperiidae (over 500 species reared from ACG, Janzen et al. 2011) remains a puzzle, especially since Bassus brooksi, a reasonably close relative to Lytopylus, attacks a very specific, large subset of ACG Hesperiidae (Janzen et al. 1998).

Figure 1 presents the NJ tree, which was much more resolved than were the phylogenetic trees produced by MP and Bayesian analyses. However all three methods were congruent with each other, both in that individuals of what are believed to be a single species grouped together, and the groups bear the same relative position to each other. We mapped the support values of the Bayesian and MP analyses on the NJ tree. Branches without values are those that collapsed in the phylogenetic analyses.

Individual species of Lytopylus tend to be rather host-specific. Of the species treated here all but one, Lytopylus jessiehillae, are found on a single host species. And even the hosts of Lytopylus jessiehillae are very similar to each other. Moreover, the results of our phylogenetic analyses (Fig. 1) show that host family is directly correlated to phylogenetic history, with sister species of Lytopylus sharing the same host family in every case (three). For members of Lytopylus, as with most other closely examined genera of Agathidinae in ACG, the regular use of multiple species of hosts by a single species is the exception and host range is phylogenetically constrained, albeit at a lower taxonomic level than appears to be the case with other Agathidinae.

Taxonomy:Sharkey et al. (2009) distinguished Lytopylus from Bassus and removed it from synonymy, however only three Neotropical species were formally transferred, i.e., Lytopylus boliviensis (Szepligeti), Lytopylus bicristatus (Enderlein), and Lytopylus facetus (Enderlein). The following is a list of all of the non-Costa Rican Neotropical species of Lytopylus known to MJS that are not treated above or elsewhere in this paper; all are new combinations: Metriosoma bicarinatum Enderlein 1920 = Lytopylus bicarinatum; Metriosoma brasiliense Enderlein 1920 = Lytopylus brasiliense; Bassus tayrona Campos 2007 = Lytopylus tayrona; Microdus femoratus Cameron 1887 = Lytopylus femoratus; Microdus melanocephalus Cameron 1887 = Lytopylus melanocephalus; Bassus pastranai Blanchard 1952 = Lytopylus pastranai; Agathis nigrobalteata Cameron 1911 = Lytopylus nigrobalteatus.

Members of Lytopylus can be distinguished from other agathidines in the New World with two characters. Most species (90%) of Lytopylus have some sculpture (rugosity, striae, etc.) on the third median tergite (Fig. 2c, T3), whereas other New World agathidines have T3 completely smooth or rarely with some very weak coriaceous sculpture (Fig. 2d). The 10% of Lytopylus that lack sculpture on T3 can be distinguished by the position of the cavity on the mesosoma (MC) into which the metasoma inserts. In species of Lytopylus (Fig. 2a) it is positioned completely above the coxal cavities of the hind leg and separated from them by a straight transverse carina (TC). In other agathidines (except Braunsia, an Old World genus) the ventral margin of MC is positioned below the dorsal margin of CC and a straight transverse carinae is lacking (Fig. 2b).

Figure 2. — a *Lytopylus* sp. Metasomal cavity (MC) situated entirely dorsal to coxal cavities (CC); a wide, high, straight, transverse carinae (TC) between MC and CC b *Therophilus* sp. MC situated partly between CC c *Lytopylus* sp. median tergite 3 (T3) showing extensive striae in anterior half d *Therophilus* sp. T3 smooth.

Key to Costa Rican species of Lytopylus (♀ and ♂)

Note: This key is restricted to those species reared in ACG and those that are recorded in the literature as occurring in Costa Rica. Since there are a minimum of 50 species of (mostly undescribed) Lytopylus occurring in Cost Rica, users of this key should compare specimens with the descriptions and images after identification using the key below or the interactive key found here.

1a	Metasoma mostly or entirely melanic	2
1aa	Metasoma mostly or entirely pale, yellow, orange, or reddish brown	4

2	Forewing evenly and deeply infuscate	Lytopylus vaughntani sp. n.
2aa	Forewing mostly hyaline, sometimes weakly infuscate basally	3

3a	Notauli sculptured with crenulae in anterior half	Lytopylus bradzlotnicki sp. n.
3aa	Notauli mostly or entirely smooth in anterior half	Lytopylus rebeccashapleyae sp. n.

4a	Median syntergite 2+3 forming a carapace that almost covers all more posterior terga; posterior margin of median syntergite 2+3 convex; 4b. median areola of propodeum well-defined and smooth with a rounded anterior border	11
4aa	Median syntergite 2+3 not forming a carapace that almost covers all more posterior terga; posterior margin of median syntergite 2+3 straight; 4bb. median areola of propodeum not as above, either pentagonal or triangular with sharp angles, or absent	5

5a	Forewing banded	Lytopylus sandraberriosae sp. n.
5aa	Forewing not banded, mostly or entirely infuscate	6

6a	Mesoscutum mostly or entirely pale, orange or reddish yellow	7
6aa	Mesoscutum mostly or entirely melanic	8

7a	Propodeum mostly smooth, lacking areolae	Lytopylus flavicalcar (Enderlein)
7aa	Propodeum sculptured with areolae	Lytopylus robpringlei sp. n.

8a	Hind leg almost entirely black	9
8aa	Hind leg reddish in large part, either coxa or femur or both reddish	10

9a	Occiput relatively sharply angled at mid-height	Lytopylus gregburtoni sp. n.
9aa	Occiput evenly rounded	Lytopylus colleenhitchcockae sp. n.

10a	Gena acute posterolaterally; 10b. median syntergite 2+3 not heavily sculptured	Lytopylus jessicadimauroae sp. n.
10aa	Gena rounded or obtuse posteroventrally; 10bb. median syntergite 2+3 heavily sculptured	Lytopylus macadamiae (Briceño and Sharkey)

11a	Third lobe of median syntergite 2+3 entirely striate	Lytopylus jessiehillae sp. n.
11aa	Third lobe of median syntergite 2+3 smooth, at least posteriorly	Lytopylus mingfangi sp. n.

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Species treatments

Lytopylus bradzlotnicki

Sharkey sp. n.

urn:lsid:zoobank.org:act:D484B71E-5CE6-48DF-AB4E-01F5D673495E

http://species-id.net/wiki/Lytopylus_bradzlotnicki

Figs 3 4

Figure 3. — *Lytopylus bradzlotnicki* sp. n. Holotype a lateral habitus b dorsal habitus c wings.

Description.

Body length 4.1 – 4.5 mm. Ovipositor length 3.9 – 4.2 mm. Gena rounded or with an obtuse angle posterolaterally. Longitudinal groove on interantennal prominence absent. Protuberances on occiput absent. Propodeum with carinae forming areolae, median areola not rounded anteriorly. Notauli well-impressed, with crenulae extending well along its length. Posterior margin of syntergum 2+3 straight. Median syntergite 2 + 3 weakly longitudinally rugose in anterior half to two-thirds, smooth posteriorly. Forewing clear except base slightly infuscate. Color as in Figs 3, 4. Color variation: Pale color of mesonotum may be more extensive or completely absent. Pale color of pronotum may be much reduced but always extensive on meso-and metapleuron. Pale color of hind femur varies from almost completely pale to almost completely melanic.

Figure 4. — *Lytopylus bradzlotnicki* sp. n. Holotype a anterior head b dorsal propodeum c lateral head and mesosoma d dorsal head and mesosoma e dorsal metasoma.

Molecular data.

BOLD process ID/ Janzen parasitoid voucher/GenBank accession:

ASHYC4707-10/DHJPAR0037962/JN034688;

ASHYD1561-09/DHJPAR0036370/JN034687;

ASHYC4706-10/DHJPAR0037961/JN034686-

Distribution.

Guanacaste Province and Alajuela Province, Costa Rica. Click here for a distribution map.

Biology.

All three rearings are from an unidentified Tortricidae of the same species feeding on rain forest Psidium guajava (Myrtaceae). Since this food plant is widely introduced into ACG pastures, it is assumed that the “natural” food plant of this caterpillar is some other plant and therefore the Lytopylus may be there as well. This tortricid lightly silks two overlapping leaves together and lives in a silk and fecal pellet tangle between them, while skeletonizing the leaf. Therefore, the wasp likely accesses the caterpillar by ovipositing through the leaf. This wasp and Lytopylus rebeccashapleyae are the only Lytopylus reared from more than 5,000 ACG tortricid rearings of dry forest and rain forest caterpillars. Austroearinus (Agathidinae) also has been reared in very low numbers from other species of tortricids than those that are Lytopylus hosts.

Etymology.

Lytopylus bradzlotnicki is named in honor of Brad Zlotnick of San Diego, California, who has enthusiastically supported the conservation of the ACG rain forest occupied by this parasitoid wasp.

Material examined.

Holotype: ♀, H6409 (DHJPAR0037961) Costa Rica: Guanacaste: Area de Conservación Guanacaste: Sector Pitilla: Estacion Pitilla: 7.ii.2010, 10.9893N, 85.4258W, 675m [AEI].

Paratypes [AEI, HIC, INBio]: Costa Rica: Alajuela: Area de Conservación Guanacaste: Sector Rincon Rainforest: Estacion Caribe: 26.v.2009, 10.9018N, 85.2749W, 415m: ♀, H7078 (DHJPAR0036370). Sector Pitilla: Estacion Pitilla: 7.ii.2010, 10.989N, 85.425W, 675m: ♀, H7071 (DHJPAR0037962). San Carlos: P.N. Arenal: Colada: 1.ii-iii.2000, 10.635N, 84.47W, 600m: ♀ H7081, ♀ H7070, ♀ H7073, ♀ H7072, ♀ H7069.