Cotesia chilonis (Munakata, 1912) (Hymenoptera: Braconidae, Microgastrinae) is a species used widely for biological control of several species of Chilo (Lepidoptera: Crambidae) stem borers. The genus name, species author and year of publication associated with this parasitoid wasp species have varied historically. Based on the available evidence, a complete account of the history and nomenclatural acts associated with C. chilonis is presented, the different alternatives are weighed and discussed, and what is considered as the best alternative is proposed. It is expected that this paper will contribute to clarity and stability in the use of this species name, author and year.

Cotesia chilonis , Microgastrinae , Chilo stem borers, biocontrol, taxonomy, Japan

Cotesia chilonis (Munakata, 1912) is a parasitoid wasp (Braconidae: Microgastrinae) originally described from Japan and widely used in biological control projects against caterpillar stem borers in the genus Chilo (Lepidoptera: Crambidae), pests of graminaceous crops in the Oriental and Afrotropical regions (Kfir et al. 1992, Polaszek and Walker 1992, Polaszek 1998).

Cotesia chilonis belongs to the Cotesia flavipes species complex, which includes four species parasitizing stemboring pests associated with sugarcane and cereal crops (Walker 1994, Muirhead et al. 2008). The monophyly of the complex is well supported by molecular (Smith and Kambhampati 1999; Michel-Salzat and Whitfield 2004; Muirhead et al. 2006, 2008) and morphological characters, such as a dorsoventrally compressed mesosoma (Watanabe 1965; Walker 1994, Muirhead et al. 2008).

The correct genus of the species, as well as its author and publication year (= original description) have long been in a state of confusion. As a result, the considerable literature on C. chilonis is replete with errors. The species has been placed either in Apanteles or in Cotesia, the authorship has been attributed either to Tetsuzo Munakata or to Shonen Matsumura, and the year of the original description has been cited as either 1910 or 1912.

Because of the importance of this species in biological control, the generic placement, author and year of description of Cotesia chilonis must be clarified.

We carefully examined the scientific literature relating to this species, including the report in which the species was originally described (Anonymous 1912). We made an effort to study all taxonomic references to Cotesia chilonis that we are aware of, and also consulted several colleagues who are proficient in Japanese and/or had seen the original paper (see Acknowledgments).

We estimated the number of citations for the different variants of the species names, species author, and year of publication by performing searches on Zoological Record, Google Scholar, and Google.

Cotesia chilonis was originally described in Apanteles (the original description has ‘Apanteles’ misspelled as ‘Apantetus’, see Fig. 1). However, Mason (1981) divided Apanteles into several genera, either new or resurrected (such as Cotesia Cameron, 1891) and transferred many known species, but unfortunately not Apanteles chilonis, to his newly proposed genera. Mason’s (1981) study was instrumental in highlighting the polyphyly of Apanteles s.l., a finding that led to the separation of Cotesia and Apanteles s.str. as separate, unrelated genera.

Figure 1. 

Copy of page 69 of the 1912 anonymous report with the original description of Cotesia chilonis (Munakata, 1912). The red square shows the original species name and attributed author.

Austin and Dangerfield (1989: 137) were the first authors to propose unequivocally the new combination, and to formally transfer the species to Cotesia (although they did so briefly in a paper section discussing unrelated species of Apanteles, and the nomenclatural act was not mentioned elsewhere). One year later Papp (1990: 117), unaware of that reference, proposed the same new combination (he did so in an Appendix rather unrelated to the main content of his paper, which was devoted to reporting Microgastrinae species from Korea). The fact that the new nomenclatural act was not clearly visible or referenced in either of those two papers probably contributed to subsequent overlooking of the new generic placement of chilonis. [Both Austin and Dangerfield (1989) and Papp (1990) attributed the authorship of the species to Matsumura instead of Munakata, see below for more discussion on that].

Cotesia has been universally recognized and accepted as a valid genus by the taxonomic and biological control research community (e.g., Yu et al. 2012, and references to the genus cited therein). However, due to the confusing circumstances detailed above, the species C. chilonis has continued to be variously placed in either Apanteles or Cotesia. For example, basic searches made in November, 2014 using the names ‘Apanteles chilonis’ or ‘Cotesia chilonis’ revealed, respectively 35 and 28 citations in Zoological Record and, 651 and 714 citations in Google Scholar. At the same time a general search in Google reveals 4,280 and 6,020 results, respectively.

Searches performed with Zoological Record, Google Scholar, and Google revealed an equally confusing mix for the author and publication year of C. chilonis (Table 1). Cotesia chilonis was originally described in a report of the Agriculture Experiment Station of Aomori, Japan. The report does not clearly state its author, but apparently it was written by Tetsuzo Munakata, although the species is mentioned in the paper as ‘Apantetus chilonis Mats.’ (Fig. 1).

Watanabe (1965) provided additional and useful information on the author and year of publication, and it should be taken as the best information available to settle the issue. Watanabe (1965: 114, reproduced in Fig. 2) states that “In 1912 Apanteles chilonis was originally described anonymously as a parasite of the rice stem borer, Chilo suppressalis, but there are certain evidences that the author is Tetsuzo Munakata.” The next sentences from Watanabe (see Fig. 2) suggest that Munakata sent the specimens to Shonen Matsumura, who identified the species as ‘Apanteles chilonis n. sp.’ and sent it back to Munakata, who then published the report with the species description in 1912.

Figure 2. 

Copy of page 114 of Watanabe (1965). The red square shows the most relevant paragraphs. The words underlined with gray were made by an unknown source to the copy available to us for study, and are not related to the present paper.

From the above account, it seems evident that Matsumura was the one recognizing the new species, but Munakata was the one publishing it. This opinion from Watanabe agrees with that of other Japanese entomologists, e.g. the braconid specialist Kaoru Maeto (personal communication) and the ichneumonid specialist Jinhaku Sonan (1930: 141). Actually, the 1930 paper from Sonan provides an interesting fact. Sonan was dealing with another species described in the 1912 report (the ichneumonid ‘Ophionellus biguttulus’ currently named ‘Temelucha biguttula’), and he also considered that, even though the original paper had written ‘Ophionellus biguttulus Mats.’, Matsumura did not describe the species but it was Munakata (compare Figs 3 and 4).

Figure 3. 

Copy of pages 141 and 142 (partially) of Sonan (1930). The red square shows Sonan’s interpretation of the species author for one of the species described by Munakata in 1912. The annotations added with a pencil (in gray) were made by an unknown source to the copy available to us for study, and are not related to the present paper.

Figure 4. 

Copy of page 67 of the 1912 anonymous report. The red square shows the original species name and attributed author (compare it against Figure 3 above).

Because the author of the species is not clear from the contents of the 1912 report, the author of the report (Munakata) should also be considered as the author of the species, as explained in The International Code of Zoological Nomenclature (ICZN). Article 50.1.1 states “However, if it is clear from the contents that some person other than an author of the work is alone responsible both for the name or act and for satisfying the criteria of availability other than actual publication, then that other person is the author of the name or act. “If the identity of that other person is not explicit in the work itself, then the author is deemed to be the person who publishes the work.” The last sentence (our italics) clearly applies here, and it should be used to recognize Munakata as the author of the species.

Watanabe, who should also be considered as the First Reviser, sensu Article 24.2 of the ICZN, unambiguously stated the authorship of the species in two papers: Watanabe (1932a: 69) and Wanatabe (1965: 114). Unfortunately he was not followed by subsequent authors. Most notably, the latest comprehensive list of world species of Braconidae (Shenefelt 1972: 468) mentioned Matsumura as the author. Shenefelt was probably the source of the mistake followed by other important references on Microgastrinae (Table 2) which unintentionally contributed to perpetuating the mistake –at least partially– until the present.

Last but not least, the year of publication has, at times, been confused by some sources (Table 2). The most common mistake (1910 instead of 1912) might have originated from another paper of Shenefelt (1965: 400), which misspelled Munakata as ‘Munakato’ and incorrectly assigned 1910 as the date for his report on Cotesia chilonis. For clarification about the actual date, we again follow Watanabe (1932a, 1932b, 1965), as he actually saw the report, studied Munakata’s specimens, and even designated a neotype (Watanabe 1965: 114; see also Fig. 2).

The unfortunate chain of omissions and confusion in publications on Cotesia chilonis has led to this important species to be referred to by several generic names, authors, and years of publication. For the sake of clarity and stability, it is useful to provide in a single paper a complete account of the history and nomenclatural acts associated with this species. Based on the revised evidence, the history of names associated with C. chilonis is presented below. It is hoped that the correct names and dates (as presently understood) are adopted by future researchers.

The decisions made in this paper about names, authors and dates related to Cotesia chilonis benefited considerably from fruitful discussion with several colleagues. Dr John Steel (University of Otago, New Zealand) helped in establishing contact with Japanese colleagues and kindly sent copies of some of the most important references used for this paper. Dr Katsuhiko Sayama (Hokkaido Research Center, Forestry and Forest Products Research Institute, Japan) kindly provided useful comments and copies of some of the most important references used for this paper. Dr Kaoru Maeto (Kobe University, Japan) kindly shared his opinions on the names and authors historically associated with the species. Dr John Huber and Dr Gary Gibson (Canadian National Collection of Insects, Ottawa, Canada) revised earlier versions of the manuscript and helped to clarify contents.