Research Article |
Corresponding author: Héctor A. Vargas ( lepvargas@gmail.com ) Academic editor: Christian Schmidt
© 2020 Sebastián Espinoza-Donoso, Dante Bobadilla, Wilson Huanca-Mamani, Marcelo Vargas-Ortiz, Héctor A. Vargas.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Espinoza-Donoso S, Bobadilla D, Huanca-Mamani W, Vargas-Ortiz M, Vargas HA (2020) A new species of Ithome Chambers (Lepidoptera, Cosmopterigidae, Chrysopeleiinae) from the Atacama Desert revealed by morphology and DNA barcodes. ZooKeys 912: 125-138. https://doi.org/10.3897/zookeys.912.47562
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Morphology and DNA barcode sequences were used to assess the taxonomic status of a micro-moth of the genus Ithome Chambers, 1875 (Lepidoptera, Cosmopterigidae, Chrysopeleiinae), whose larvae feed on inflorescences of Prosopis tamarugo Phil. (Fabaceae), a tree native to the Pampa del Tamarugal, Atacama Desert, northern Chile. As a result, Ithome tamarugensis Vargas, sp. nov. is described and illustrated. Its genitalia are remarkably similar to those of Ithome tiaynai Vargas, 2004 from coastal valleys of the Atacama Desert. However, the two species can be recognized by the shape of the phallus in males and the shape of the antrum and ductus bursae in females. The genetic distance between DNA barcodes of I. tamarugensis and I. tiaynai was 3.0–3.3% (K2P), and a maximum likelihood analysis indicated that they are in reciprocally monophyletic clusters, providing additional support for the heterospecific status suggested by morphology.
Florivorous larvae, Ithome concolorella (Chambers, 1875), Ithome tiaynai Vargas, 2004, Prosopis tamarugo Phil.
The Atacama Desert harbors a distinctive biota characterized by some endemic plants and animals (e.g.
Ithome Chambers, 1875 (Lepidoptera, Cosmopterigidae, Chrysopeleiinae) is a New World genus of micro-moth with 19 species currently described. Eighteen species of Ithome have their type locality on mainland America and one in the Galápagos Islands (
Two of the species of Ithome originally described from the southern United States have expanded their ranges outside of mainland America and are pests of Fabaceae. Ithome concolorella (Chambers, 1875), described from Texas, became a pest of Acacia farnesiana (L.) Willd. and Prosopis chilensis (Mol.) Stuntz in the Hawaiian Islands because feeding by its larvae reduces the flower production of these trees, which are important nectar sources for honey bees (
Ithome tiaynai Vargas, 2004 is the only representative of the genus currently described from Chile. Its larvae feed on inflorescences of Acacia macracantha Willd. (Fabaceae) in coastal valleys of the Atacama Desert (
We used morphology and DNA barcode sequences (sensu
Larvae of Ithome were collected on inflorescences of P. tamarugo in La Tirana village, at about 1000 m elevation in Tamarugal Province, Tarapacá Region, northern Chile, in August 2018 and September 2019. The inflorescences with larvae were placed in plastic vials with paper towel at the bottom and brought to the laboratory, where additional inflorescences were provided until the larvae finished feeding and pupated. The vials were observed daily until adult emergence. The adults were mounted and their abdomens were removed and placed in hot KOH 10% for a few minutes for dissection of their genitalia, which were stained with Chlorazol black and Eosin Y and slide mounted with Euparal. Description of genitalia follows
Genomic DNA was extracted following the procedures described by
IDEA Colección Entomológica de la Universidad de Tarapacá, Arica, Chile
Six DNA barcode sequences were obtained (Table
Species | BOLD accession | GenBank accession | Country |
---|---|---|---|
Ithome curvipunctella (Walsingham, 1892) | BBLOB1350-11 | USA | |
Ithome tamarugensis Vargas, sp. nov. | MN586873 | Chile | |
I. tamarugensis | MN586874 | Chile | |
I. tamarugensis | MN586875 | Chile | |
Ithome tiaynai Vargas, 2004 | MN586876 | Chile | |
I. tiaynai | MN586877 | Chile | |
I. tiaynai | MN586878 | Chile |
Ithome
sp. (
Ithome concolorella; misidentification (
Chile, Tarapacá Region, Tamarugal Province, La Tirana village, 20°20'S, 69°39'W.
Holotype male, pinned, genitalia slide HAV-1307. Original labels: “Chile, Tamarugal, La Tirana, emerged October, 2019, H.A. Vargas coll.”, “ex-larva inflorescence Prosopis tamarugo, collected September, 2019”, “Holotype / Ithome / tamarugensis / Vargas” [red handwritten label] (
Paratypes (Five males, five females). One male (genitalia slide HAV-1309), two females (genitalia slides HAV-1308, 1310), same data as for holotype (
The mainly shiny black adults of I. tamarugensis resemble those of I. tiaynai, the only other Chilean congeneric. In addition, the genitalia of the two species are outstandingly similar. However, the male of I. tamarugensis has the phallus dorsally excavated in the middle, slightly broadened subapically, and with a deep cleft apically. In contrast, the phallus of I. tiaynai is parallel sided in the middle, slightly straightening subapically, and with a small cleft apically. The female of I. tamarugensis has a short cylindrical antrum and coiled ductus bursae. In contrast, the female of I. tiaynai has a mainly undifferentiated antrum and conic ductus bursae. Although signa were not mentioned in the original description of I. tiaynai, recent observations have revealed the presence of two signa similar to those found in I. tamarugensis.
Male (Fig.
Head. Shiny dark grey on face, shiny black dorsally. Haustellum shiny dark grey. Labial palpus shiny black. Antenna shiny black, filiform, about 3/4 wing length; pecten formed by a dark brown scale placed near base of scape.
Thorax. Shiny black dorsally, brownish grey laterally. Foreleg mainly shiny black; coxa brownish grey laterally; brownish grey at middle and apex of tibia and apex of tarsomeres. Midleg mainly shiny black; two brownish grey tibial spurs; brownish grey at apex of tarsomeres. Hindleg mainly shiny black laterally, brownish grey medially; tibia with longitudinal stripe of short, hair-like, yellowish-grey scales dorsally; four brownish-grey tibial spurs; tarsomeres mainly brownish grey with a few darker areas. Forewing shiny black with slightly differentiated (or sometimes absent) brownish-grey transverse stripe subapically; fringe brownish grey. Hindwing shiny black on basal half, brownish grey on distal half; fringe brownish grey.
Abdomen (Fig.
Male genitalia and pregenital abdominal segments of Ithome tamarugensis Vargas, sp. nov. A Abdominal segments VII and VIII B genitalia in ventral view, phallus removed, asterisk shows the right valva C phallus in lateral view D apex of the hook of the left valva (marked with arrow in B) E apex of phallus, arrow shows the dorsal excavation F cornutus. Scale bar: 0.1 mm.
Male genitalia
(Fig.
Female. Similar to male in size and coloration. Hindwing brownish grey; fenulum with three acanthae. Abdomen brownish grey. Separation between VI and VII segments slightly differentiated.
Female genitalia
(Fig.
Ithome tamarugensis is known from the Pampa del Tamarugal (Fig.
All the specimens of I. tamarugensis examined in this study were reared from larvae collected on P. tamarugo (Fig.
The specific epithet is derived from the Pampa del Tamarugal, where the type locality of I. tamarugensis, La Tirana village, is located.
Despite the extreme aridity of the Atacama Desert, some reports in the last decades suggest that it harbors a distinctive micro-moth fauna associated with native plants (e.g.
Although there are no previous studies dealing with phylogenetic relationships of the species of Ithome, the morphology suggests that I. tamarugensis and I. tiaynai are closely related. First, the highly specialized sternum VIII of the male abdomen is indistinguishable among them, but clearly different from this structure in the remaining species of the genus (
The current data suggest that the geographic ranges of the two species of Ithome of northern Chile are restricted to different ecological zones of the Atacama Desert, the coastal valleys in the case of I. tiaynai, and the Pampa del Tamarugal in the case of I. tamarugensis. A similar geographic pattern has been described for two morphologically close micro-moths of the genus Cryptophlebia Walsingham (Tortricidae), with C. cortesi Clarke, 1987 restricted to the coastal valleys and C. saileri Clarke, 1987 to the Pampa del Tamarugal (
We thank Sjaak Koster and Christian Schmidt for kind suggestions on a previous version of the manuscript and Lafayette Eaton for checking the English. The study was supported by project UTA-MAYOR 9722–18 from Universidad de Tarapacá.