DNA barcoding reveals a largely unknown fauna of Gracillariidae leaf‐mining moths in the Neotropics

Abstract

Higher taxa often show increasing species richness towards tropical low latitudes, a pattern known as the latitudinal biodiversity gradient (LBG). A rare reverse LBG (with greater richness towards temperate high latitudes) is exhibited by Gracillariidae leaf-mining moths, in which most described species occur in northern temperate areas. We carried out the first assessment of gracillariid species diversity in two Neotropical regions to test whether the relatively low tropical species diversity of this family is genuine or caused by insufficient sampling and a strong taxonomic impediment. Field surveys in six French Guianan and one Ecuadorian site produced 516 gracillariid specimens that were DNA barcoded to facilitate identification and to match larvae inside leaf mines with adults. Species delineation from sequence data was approximated using Automatic Barcode Gap Discovery and Refined Single Linkage Analysis through the Barcode Index Number system, and the proportion of described/undescribed species was estimated after comparison with types of 83% of described species. Locally, alpha-diversity far exceeds that of any known temperate fauna, with as many as 108 candidate species (59.3% as singletons) collected at one site, and with an estimated species richness lower bound of 240 species. Strikingly, at least 85% of the species collected as adults were found to be undescribed. Our sampling represents the most thorough survey of gracillariid species diversity in the Neotropics to date and the results from both our molecular and morphological analyses indicate that the current reverse LBG seen in this group is an artefact of insufficient sampling and a strong description deficit in the Neotropics.

Systematics and biology of some species of Micrurapteryx Spuler (Lepidoptera, Gracillariidae) from the Holarctic Region, with re-description of M. caraganella (Hering) from Siberia

“…In conclusion, our study documents another example of how DNA barcoding can help to reveal overlooked species and clarify taxonomic issues (Jin et al 2013; Landry et al 2013; Lees et al 2013; Mutanen et al 2013; Huemer et al 2014). Moreover, our analysis highlights the need for a careful revision of Parectopa and Micrurapteryx in the Nearctic and Palearctic Regions, particularly in the context of a broader phylogenetic analysis of the Gracillariidae.…”

“…Many species of gracillariids remain to be discovered, especially in the tropical regions (Lees et al 2013; Brito et al 2013) but also in the Palearctic (Laštůvka et al 2013; Kobayashi et al 2013; Kirichenko et al 2015) and Nearctic regions (Davis and Deschka 2001). …”

Revision of Mandarella Duvivier from Taiwan, with a new species, new synonymies and identities of highly variable species (Insecta, Chrysomelidae, Galerucinae, Alticini)

“…In addition, previous authors have noted that variations in body color and antennomeres may be the result of local adaptation that is not indicative of species boundaries (Kurachi et al 2002, Nahrung and Allen 2005, Quinzin and Mardulyn 2014). Molecular approaches have been applied broadly in systematics of various insects and have fueled taxonomic debates about species recognition, especially when morphological characters are insufficient (Brown et al 2012, Kumar et al 2012; Lee et al 2013, Lees et al 2014, Park et al 2011, Tsai et al 2014). Sequences data from (COI)cytochrome oxidase subunit I , a small fragment of mitochondrial DNA, have been viewed as efficient markers in Chrysomelidae and have been exploited to resolve debates in identification (Germain et al 2013, Kubisz et al 2012, Lopes et al 2015) and elucidate species complex phylogenetics (Quinzin and Mardulyn 2014).…”

Hypermetamorphosis in a leaf-miner allows insects to cope with a confined nutritional space

“…In Lepidoptera, such hypermetamorphosis mostly occurs in Gracillariidae (and sometimes in Epipyropidae and Phyllocnistidae) which is one of the largest families of Lepidoptera containing over 2,000 described species, most of them leaf-miners (Lees et al 2014). This unusual phenomenon allows leaf-miner insects to evolve during a single moult from ''sap-feeding'' to ''tissue-feeding'' habits during their larval lifetime (Davis and Deschka 2001).…”