Darwin Wasps from the Andean-Amazonian Region in Caquetá, Colombia: A Taxonomic Synopsis of the Genera of Cremastinae (

Objective. This study proposes a taxonomic synopsis for the genera of the subfamily Cremastinae (Hymenoptera: Ichneumonidae) from the Andean-Amazonian region in Caquetá, Colombia. Additionally, it provides an illustrated taxonomic key for its identification. Scope. To promote knowledge of the diversity of Cremastinae in Caquetá, Colombia. Methodology. This study utilized specimens collected using Malaise traps and Suspendable traps during the term of the project titled “Taxonomy of Pipunculidae (Diptera: Insecta) of Colombia.” The collection efforts covered rural areas such as sugarcane crops ( Saccharum officinarum ) and secondary forest areas, including both ground and canopy levels, across all 16 municipalities of the Caquetá department. Results. A total of 306 individuals of Cremastinae were examined. Seven genera were identified, with six of them representing new records for Colombia: Creagrura Townes, 1971; Eutanygaster Cresson, 1865; Pristomerus Curtis, 1836; Temelucha Forester, 1869; Trathala Cameron, 1899 and Xiphosomella Szépligeti, 1905. Conclusions. The results contribute to a better understanding of the real distribution range of this taxonomic group in the region.


Introduction
Darwin wasps (Hymenoptera: Ichneumonidae) are parasitoids wasps considered one of the largest families in the animal kingdom and natural enemies of a wide range of holometabolous insects and spiders (Broad et al., 2018;Klopfstein et al., 2019). According to Yu et al. (2016), there are approximately 4,420 species of Ichneumonidae in the Neotropical region, and around 25,000 species worldwide.
One of the most significant groups within Ichneumonidae is the subfamily Cremastinae Förster, 1869. This cosmopolitan subfamily comprises 35 genera, with 14 genera known in the Neotropical region (Yu, et al., 2016).
Cremastinae plays a vital role in biological control, parasitizing a wide range of hosts, mainly caterpillars from moth families such as Coleophoridae, Hesperiidae, Psychidae, Pyralidae and Tortricidae. They also affect beetle larvae from Buprestidae and Chrysomelidae, as well as wasps of Tenthredinidae (Okada and Oike, 1940;Dasch, 1979). Additionally, some species are known to parasitize aquatic lepidopteran larvae (Gauld, 2000;Fernandes et al., 2018). There are endoparasites with a koinobiont strategy that consists of temporarily paralyzing the host and allowing it to continue growing until reaching a certain size or stage of development before causing its death (Marquina-Montesinos 2019).
Distinguishing features of Cremastinae from the other Darwin wasps subfamilies include a sclerotized bridge that separates the membranous cavities of the basitarsi and tibial spurs from the tibiae (Townes, 1958).
The Cremastinae fauna from Colombia has not been extensively studied, with only three species of the Eiphosoma Cresson, 1865 reported by Gauld (2000) and Yu, et al., (2016). Therefore, we propose a taxonomic synopsis for the genera of Cremastinae in Caquetá, Colombia, which includes a diagnosis and an illustrated taxonomic key.

Materials and methods
This study was based on specimens collected during the field phase of the project titled "Taxonomy of Pipunculidae (Diptera: Insecta) of Colombia." These specimens are currently deposited in the Laboratorio de Entomología de la Universidad de la Amazonia (LEUA) in Caquetá, Colombia. Darwin wasps were collected using Malaise traps and Suspendable traps continuously from October 26, 2016 to April 12, 2017, for approximately 6.5 months without interruption day and night. The sampling efforts covered both rural areas, such as sugarcane crops (Saccharum officinarum Linnaeus, 1753) from the Poaceae family, and secondary forest areas (ground and canopy) across the 16 municipalities of the Caquetá department.
For the identification and examination of the morphological characteristics, dry mounts were prepared. Direct mounting with entomological pins was used, with glue applied laterally to the mesosoma. This method prevented perforation of the specimens while preserving their morphological characters and coloration.
Individuals were examined and identified using an Olympus SZ61 stereoscope with a 2x auxiliary lens. The dichotomous keys and terminology proposed by Gauld (2000) for the genera of Cremastinae were followed. High-resolution photographs were taken at different focal depths using a Leica digital camera DFC500 attached to a Leica M205C stereomicroscope, connected to a computer with the Leica Application Suite LAS V3.6 software, which includes the Syncroscopy program to align the photographs. The images were edited using the Adobe Photoshop CS6® software tools.
The previous key by Gauld (2000) was modified to incorporate the genera of Cremastinae discovered in Caquetá, Colombia. Maps displaying the geographic records of each genus were generated using SimpleMappr software (Shorthouse, 2010).
In the list of examined specimens, label data are provided exactly as presented on the labels. Square brackets ([]) are used to indicate additional data that are not provided on the specimen labels. When specimen labels contain identical data, the term 'idem' is used, and only the differing data are included.
Eiphosoma is a New World genus that encompasses 56 described species, with the majority occurring in the tropical zone of South America (Gauld, 2000;Yu, et al., 2016). In Colombia, three species have been recorded: Eiphosoma laphygmae Costa Lima, 1953, Eiphosoma nigrum (Szepligeti, 1906, and Eiphosoma vitticolle Cresson, 1865(Yu, et al., 2016. Most Eiphosoma species are commonly found in lowland, open, and degraded habitats (Ashley et al., 1982). Several species of Eiphosoma hold biological importance as parasitoids attacking caterpillars that are pests of Lepidoptera in agricultural systems (Pozo, 2000).
Diagnosis. Coloration. Eiphosoma species are yellow with black spots, although some species are predominantly black (Fig. 1B). Head (Fig. 4C). The mandible is not twisted and exhibits a distinct ventral edge, with the upper tooth longer and wider than the lower tooth. Mesosoma. The mesoscutum displays printed notation and punctuations concentrated in the anterior and posterior parts, while the scutellum can be smooth or punctuated. The metapleuron may be smooth or dotted, and a pleural carina is present. The propodeum can be smooth, coriaceous, rough, or striated, and carinae are present on the posterior femur with a ventral tooth. Fore wing length between 3.8 to 9.7 mm ( Fig. 3E), with or without 3rs-m vein. Metasoma. The laterotergite II lacks a thyridium (Fig. 2B), and the ovipositor is either straight or possesses a sinuous apex (Gauld, 2000  Eutanygaster is a small Neotropical genus with two described species: Eutanygaster brevipennis Cameron, 1911 and Eutanygaster tabascensis (Morley, 1913). Additionally, there are several undescribed taxa within this genus (Gauld, 2000). In the past, Eutanygaster was often confused with Xiphosomella; and the species E. tabascensis was incorrectly placed within that genus (Townes and Townes, 1966).

Diagnosis. Coloration.
Primarily black, although some specimens may exhibit a more yellowish ventral coloration (Fig. 1C). The head (Fig. 4D) is characterized by short mandibles that are not crooked, with a prominent ventral ridge. The upper tooth is slightly longer and thicker than the lower tooth. In the mesosoma, the mesoscutum has a broad, but superficially imprinted notation, appearing smooth and punctuated. The scutellum is convex and smooth, lacking lateral carinae. Abbreviations: T: Thyridium; Lt: Laterotergite; Clle: Scutellar lateral longitudinal carina. carinae; Mesopleuron smooth, dotted anteriorly; propodeum with complete anterior and posterior carinae. Fore wing 4.5 to 6.0 mm (Fig. 1C, 3F). It lacks an areolet, but has contiguous M and Rs veins, 2rs-m is absent. The pterostigma is very thin. In the metasoma, tergite II lacks a thyridium and has a pendant laterotergite (Gauld, 2000).
Pristomerus is a cosmopolitan genus that includes 99 registered species (Yu et al., 2016), most distributed in tropical and subtropical areas. Larvae are endoparasitic of Lepidoptera. In the New World tropics, Pristomerus is not as species-rich as in the Old World, perhaps because the closely related endemic genus Xiphosomella is extremely species-rich (Gauld, 2000).

Diagnosis.
Coloration is mainly yellowish to reddish brown (Fig. 1D). The head (Fig. 1C) features untwisted mandible, without a prominent ventral border, with slightly biconcave upper tooth. The mesosoma has a moderately to weakly imprinted notation on the mesoscutum, which can be smooth or granular with few punctures. The scutellum is moderately convex, smooth and polished without lateral carinae. The metapleuron is usually dotted, sometimes granular or leathery, and the propodeum usually has complete anterior and posterior carinae. The fore wings measure 2.1 to 5.1 mm. (Fig. 1D) (Gauld, 2000).
Temelucha is easily distinguished from other Cremastinae genera by the shape of the first metasoma segment, where the tergite margins enclose the sternites. Temelucha species do not have a tooth on the posterior femur or a discernible thyridium.
Only a few species have a sinuous apex on the ovipositor. Morphologically, they bear resemblance to Trathala species, although Temelucha species never have the first tergite enclosing sternites I. Additionally, Temelucha species closely resemble Neleothymus Förster, 1869 species, suggesting that Neleothymus could be considered as a specialized group within Temelucha (Gauld, 2000).

Diagnosis. Coloration.
Mainly yellowish-brown with few black markings (Fig. 1E). Head. (Fig. 1E). The mandible is not twisted with a narrow ventral ridge, with the upper tooth slightly longer and sturdier than the lower tooth. Mesosoma: The mesoscutum exhibits weakly imprinted or vestigial notation, generally appearing granulated with scattered punctures, while the scutellum is typically flattened. The mesopleuron is generally smoothed with fine punctures anteriorly. The propodeum usually displays more or less complete carinae, although the superomedial area and petiolar can be confluent, sometimes with a transversely strigose area. Fore wing length ranges from 2.2 to 4.5 mm (Fig. 1E). Metasoma. The first segment of the  metasoma features tergite margins enclosing the sternites (Fig. 4E). No species within the genus possess a tooth on the posterior femur, and the thyridium is not detectable. Only a few species have a sinuous apex on the ovipositor (Gauld, 2000).
Trathala is a cosmopolitan genus comprising 97 described species (Yu et al., 2016). Structurally, Trathala exhibits a moderate range of variations in both, the Old and New Worlds, and its differentiation from the Holarctic genus Cremastus Gravenhorst, 1829 and the South African genus Ricrena Cameron, 1906 is not entirely clear. These issues, along with the classification status of the genus, can only be resolved when the highly diverse tropical faunas are better understood in terms of natural species groups within the Ichneumonidae (Gauld, 2000).

Diagnosis. Coloration.
The coloration is variable, with complete blackness being rare (Fig. 1F). Head. (Fig. 1F) The mandibles are not twisted and lack a prominent ventral flange. Generally, the upper tooth is slightly longer and stouter than the lower tooth, although there are cases where the lower tooth is slightly longer. Mesosoma. The mesoscutum exhibits weak to moderately strong notauli impressions, and it is typically granulated or punctuated with granular sculpture on interstices. The scutellum is convex and exhibits various sculptures, usually lacking carinae laterally. epicnemial carina is complete, and the posterior transverse carina is complete or slightly raised medioventrally. The propodeum features anterior and posterior transverse carinae, generally complete, with the presence of lateromedial and laterolongitudinal carinae often complete between the transverse carinae, rarely with both absent. The fore wing lacks an enclosed areolet, and the pterostigma is moderately stout, usually as wide or wider than the first subdiscal cell. The fore wing length ranges from 1.7 to 11.8 mm (Fig. 1F). Metasoma. Tergite II without thyridium, and a folded laterotergite is present beneath the under tergite. The margins of tergite I are parallel and widely separated, thereby exposing the sternites (Fig. 4F). Notably, no Trathala species possesses an areolet on the fore wing, and they also lack a tooth on the posterior femur (Gauld, 2000).  (Yu et al., 2016;Azevedo et al., 2015;Fernandes et al., 2019a;Fernandes et al., 2019b;Fernandes et al., 2020a;Barata, et al., 2022;Fernandes, et al., 2023).

(original designation).
Xiphosomella is a heterogeneous genus found in the New World, comprising 54 described species (Yu, et al., 2016). Additionally, a significant number of species are still awaiting description. In terms of structure, Xiphosomella, as currently defined Townes (1971), exhibits the widest range of variation among all the genera in the Cremastinae subfamily. This stands in contrast to other parts of the Cremastinae, where the generic distinction is based on morphologically distinct species groups (Gauld, 2000). This situation has been further complicated by the fact that the difference between Xiphosomella and Pristomerus is not as straightforward as suggested by Townes (1971). Presently, the primary distinguishing feature between the two genera is the position of the thyridium. In Xiphosomella, the thyridium can be located close to the anterior margin of tergite II to approximately in the center of the tergite. In Pristomerus, the thyridium is consistently found near the anterior margin of the tergite (Gauld, 2000).

Diagnosis. Coloration.
Xiphosomella species exhibit a predominantly yellowish or reddish-brown coloration, often with varying infusions. However, there are rare cases where the coloration is mostly black, although this is not common (Fig. 1G). Head. The mandible is not crooked and lacks a prominent ventral ridge. Typically, the upper tooth is slightly longer, and the lower tooth is more robust, although there are rare instances where the lower tooth is longer (Fig. 3B). Mesosoma. The mesoscutum shows a range of notation impressions, varying from weak to strongly imprinted. It is usually smooth or grainy with scattered punctures, although extensive punctuation is rare. The fore wings measure 2.4 to 8.3 mm (Fig. 1G). The scutellum is moderately convex, smooth and polished without lateral carinae (Fig. 2F). The mesopleuron is generally smooth, with fine punctuations in the anterior part. The propodeum typically has both anterior and posterior transverse carinae, which are usually complete, although there are cases where both carinae are absent (Gauld, 2000).

Discussion
This study contributes to regional and national entomology by providing the first record of the genera Creagrura, Eutanygaster, Pristomerus, Temelucha, Trathala and Xiphosomella in Colombia.
The record of these genera highlights the significance of conducting faunal inventories and studying the distribution and diversity of Darwin wasps, particularly in poorly sampled areas like the Colombian Andean-Amazonian region. It highlights the need for comprehensive research to accurately determine the distribution of genera and species throughout the country.
Notably, Eiphosoma and Xiphosomella were the most abundant genera observed, indicating that they can be readily collected in foothills and Amazon plain forests. Despite conducting an extensive six-month sampling effort across various habitats, the other genera, although their rarity or difficulty of collection could not be definitively determined, exhibited very low abundance, including the sugarcane crops, using different sampling methods, with 20 sampling stations distributed throughout the department (Parada-Marín, et al., 2021). Creagrura, Eutanygaster, Pristomerus, and Temelucha genera were exclusively collected in sugarcane crops, but Eiphosoma, Trathala and Xiphosomella were not only collected in sugarcane crops but also from secondary forest in both the canopy and understory.

Conclusions
This study highlights the significance of conducting inventories of understudied groups like Cremastinae, as it contributes valuable scientific findings that enhance our understanding of the country's biodiversity. These findings serve as a foundation for future research in areas such as taxonomy, systematics, ecology, biogeography and conservation.
The newly recorded genera in this study expand our knowledge of the New World geographical distribution and habitat preferences of Cremastinae in the previously unexplored Andean-Amazonian region of southeastern Colombia.
Furthermore, the dichotomous key to the genera of Cremastinae provided in this study will facilitate their identification by illustrating critical characters and presenting relevant diagnostic information to distinguish them from other genera.