Cecidonius pampeanus, gen. et sp. n.: an overlooked and rare, new gall-inducing micromoth associated with Schinus in southern Brazil (Lepidoptera, Cecidosidae)

Abstract

Galls induced by the larval stage of cecidosids (Lepidoptera: Cecidosidae) are complex, multi-trophic systems, still poorly studied. They may be associated with other insect feeding guilds, including inquilines, kleptoparasites, cecidophages, parasitoids, and predators. By causing death of the gall inducer early in life and altering the gall phenotype, inquilines may lead to misidentification of the true gall inducers. Here, we describe through light and scanning electron microscopy Cecidonius pampeanus, a new genus and species of cecidosid moth, from the Pampa biome, south Brazil. It induces unnoticed, small galls under swollen stems of Schinus weinmannifolius Mart. ex Engl. (Anacardiaceae). Such galls are severely attacked early in ontogeny either by unidentified parasitoids belonging to Lyrcus Walker (Pteromalidae) that feed upon the inducer, or by inquiline wasps of the genus Allorhogas Gahan (Braconidae). The inquilines modify the galls into large ones that last longer and promptly call attention. Free-living galls are rare and dehiscent, pupation of C. pampeanus occurring on the ground. Due to these reasons the true inducer has been overlooked in this case for more than a century. Additionally we inferred a phylogeny for Cecidosidae using sequences from mitochondrial and nuclear loci, and characterized genetic variation and gene flow across ten populations. Despite its natural history similarities with the African genus Scyrotis, Cecidonius is a much younger lineage, more closely related to the Neotropical cecidosids. C. pampeanus populations, which are now confined to a few mountain areas within its distribution range due to habitat destruction, are also genetically isolated, requiring conservation measures.

Overlooked gall-inducing moths revisited, with the description of Andescecidium parrai gen. et sp. n. and Oliera saizi sp. n. from Chile (Lepidoptera, Cecidosidae)

“…), using the PureLink genomic DNA kit (Life, Invitrogen, USA) following the manufacturer’s instructions. Sequences of Cecidoniuspampeanus , Cecidonius sp., Cecidoseseremita Curtis, Dicranosescongregatella (Brèthes), Eucecidosesminutanus Brèthes, Olieraargentinana , Scyrotisgranosa (Meyrick) were previously generated by Moreira et al (2017). Adelidae, Incurvariidae and Prodoxidae sequences were incorporated from the GenBank/NCBI databases, as well as the African cecidosid S.pulleni Mey.…”

“…Approximately 2.5 Kb of gene segments were amplified by polymerase chain reaction (PCR): 1421 bp of the cytochrome oxidase subunit I (COI), 474 bp of the 16S ribosomal RNA (16S) and 395 bp of the Wingless (Wg) gene loci, with primers and conditions described in Moreira et al (2017). PCR products were purified using the enzymatic method (exonuclease and alkaline phosphatase), sequenced with BigDye chemistry, and analyzed in an ABI3730XL (Applied Biosystems Inc.).…”

“…This situation is found for many gall-inducing insects, including other Lepidoptera (e.g., Morris 2000, van Noort et al 2007, Luz et al 2015). This was recently demonstrated in detail for Cecidoniuspampeanus Moreira and Gonçalves, a cecidosid moth whose identity was overlooked for more than one hundred years, as its galls had been erroneously described as induced by their hymenopteran inquilines (Moreira et al 2017). …”

“…They include seven genera and 19 species that are distributed in southern South America, southern Africa, and New Zealand (for taxonomic reviews see Davis 1988, Hoare and Dugdale 2003, Moreira et al 2017). In spite of their interesting biology, close association with their Anacardiaceae host-plants ( Schinus L.) and broad geographical distribution, the diversity of Cecidosidae remains mostly unexplored in the Neotropical region.…”

“…Their galls may consist of complex ecological systems that involve additional organisms, in addition to the host-plant and corresponding gall-inducer. For example, other insects can act in multi-trophic levels in these galls, as inquilines, kleptoparasites, or cecidophages, among other feeding guilds, including predators, parasitoids or successors that use them just for shelter (Moreira et al 2017). In the case of kleptoparasites and inquilines, the original inducer might be killed and thereafter the gall is usurped by the invader (Ronquist 1994, van Noort et al 2007).…”