A literature-based review of Hymenoptera Parasitica and Chrysidoidea from Reunion Island

Abstract A review of the genera and species of Hymenoptera Parasitica and Chrysidoidea reported so far from Reunion Island is provided with host information. Data presented here is based on a review of the existing literature by the authors. The list includes: (1) 156 species of Ichneumonoidea belonging to 65 genera and 25 subfamilies (Braconidae: Agathidinae, Alysiinae, Aphidiinae, Braconinae, Charmontinae, Cheloninae, Doryctinae, Euphorinae, Gnamptodontinae, Microgastrinae, Opiinae; Ichneumonidae: Banchinae, Campopleginae, Cremastinae, Cryptinae, Diplazontinae, Ichneumoninae, Mesochorinae, Metopiinae, Ophioninae, Orthocentrinae, Pimplinae, Tersilochinae, Tryphoninae); (2) 121 species of Chalcidoidea belonging to 56 genera and 8 families (Agaonidae, Aphelinidae, Chalcididae, Encyrtidae, Eulophidae, Eupelmidae, Eurytomidae, Ormyridae, Pteromalidae, Signophoridae, Torymidae and Trichogrammatidae); (3) seven species of Cynipoidea (family Figitidae); (4) six species of Chrysidoidea in three families (Bethylidae, Chrysididae, Dryinidae); (5) five species of Platygastroidea (families Platygastridae and Scelionidae); (6) five species of Diaprioidea (family Diapriidae); (7) four species of Ceraphronoidae (families Ceraphronidae and Megaspilidae); and (8) two species of Evanioidea (family Evaniidae). This review records a total of 306 species.


Introduction
The parasitoids of the Hymenoptera Apocrita form one of the most species-rich groups of animals, potentially representing more than 20% of the world's insects (LaSalle and Gauld 1992). Furthermore, they play an important role in the regulation of insect pests and many of them are used in biological control programs all over the world. The failures and successes of their use in biocontrol have been extensively reviewed (e.g. DeBach 1964, Funasaki et al. 1988, DeBach and Rosen 1991, van Driesche and Bellows 1996, Smith 1996, Solomon et al. 2001. To date, the diversity of Hymenoptera in La Réunion has been partially studied. There have been some studies on the hymenopteran diversity around 1950. Risbec (1957) and Benoit (1957) reviewed the Chalcidoidea/Proctotrupoidea and the Ichneumonoidea, respectively. To our knowledge, after 1957 almost nothing was published on the hymenopteran diversity of Reunion Island (only Wiebes 1981 on the figwasps) untill 2001 when Vayssière et al. published a review of the pests and their natural enemies on several crops of the island. Two years later, this work was followed and updated by the publication of a book (Quilici et al. 2003). At this time, taxonomic work on Parasitica was far from exhaustive because it only dealt with parasitoids associated with important pests. In fact, a lot of work has been done to combat key pests such as Tephritid flies (Diptera: Tephritidae) in mango and cucurbit fruits. Nevertheless, the taxonomic review of the fauna from Reunion Island has been conducted for a few groups. Rousse and Villemant (2012) reviewed the Ichneumonidae and provided a key to species of the Island with 15 species new to science. Some subfamilies of Braconidae (Ichneumonoidea) have been reviewed: Madl (2007, Agathidinae), Fischer and Madl (2008, Opiinae), Rousse and Braet (2012, Euphorinae), Braet et al. (2012, Cheloninae), Rousse and Gupta (2013, Microgastrinae). Madl and van Achterberg (2014) published a catalogue of the Braconidae of Malagasy subregion, including Reunion Island. Fischer (2014) published an important paper on Alysiinae and Opiinae (Braconidae) with 12 species new to science. Until to now the study of Ichneumonoidea has added more than 140 species to the list of Benoit (1957).
Superfamilies other than the Ichneumonoidea were less studied. For example, the Chalcidoidea may have a diversity similar to or higher than that of the Ichneumonoidea. In fact, there are a lot of unpublished data from the work of Marc Attié (2001)(2002)(2003)(2004). The material collected during his work is now at the CBGP in Montpellier (France).
By reviewing the published data, this work provides a first list of all the Hymenoptera Parasitica of Reunion Island and the superfamily Chrysidoidea (belonging to the Hymenoptera Aculeata). We think this work will be a valuable tool for future inventories or work on biological control. Indeed, this work allows the detection of new indigenous natural enemies (e.g. Pristomerus river, Ichneumonidae, parasitoid of Prophantis smaragdina, Lepidoptera) and invasive hyperparasitoid or parasitoid of predators (e.g. Homalotylus eytelweinii, Encyrtidae, a parasitoid of Rodolia chermesina, Coccinellidae).

Arrangement of the checklist
In this review, superfamilies are treated according to their importance, the most diverse (Ichneumonoidea) presented first. Genera known so far from Reunion Island are grouped according to subfamilies, and family affiliation. For convenience, families, subfamilies, genera and species are listed in alphabetical order. Genera and species names are followed by the names of the author(s) and year of first description, then by the reference of the record and, when available, host data.
The review includes three tables summarizing (1) the Ichneumonoidea, (2) the Chalcidoidea, (3) the records for the other superfamilies, each with general host information.

Discussion
The present work is a literature-based review. Therefore, users should be aware that it might contain some mistakes present in the original literature. However, all references are listed so that the records can be validated.
This review lists 306 species of parasitoid Hymenoptera recorded from the island belonging to eight superfamilies. Of the species and genera reported from the island, at least 1 genus and 14 species of Ichneumonidae (Rousse and Villemant 2012), and 1 genus and 25 species of Braconidae (Madl 2007, Rousse and Braet 2012, Rousse and Gupta 2013, may be endemic as they currently only are recorded from Reunion Island. On the other hand, several species are now cosmopolitan in distribution due to their widespread use as biocontrol agents.
When compared with other geographical regions of the world, the study of hymenopteran parasitoid diversity in Reunion Island is still preliminary. Many new taxa will probably be found from the region in the future, and thus this checklist will need to be periodically updated.
Recorded from: Risbec 1957 Host information: Unknown