Turning Up the Heat on a Hotspot: DNA Barcodes Reveal 80% More Species of Geometrid Moths along an Andean Elevational Gradient

Abstract

We sampled 14,603 geometrid moths along a forested elevational gradient from 1020–3021 m in the southern Ecuadorian Andes, and then employed DNA barcoding to refine decisions on species boundaries initially made by morphology. We compared the results with those from an earlier study on the same but slightly shorter gradient that relied solely on morphological criteria to discriminate species. The present analysis revealed 1857 putative species, an 80% increase in species richness from the earlier study that detected only 1010 species. Measures of species richness and diversity that are less dependent on sample size were more than twice as high as in the earlier study, even when analysis was restricted to an identical elevational range. The estimated total number of geometrid species (new dataset) in the sampled area is 2350. Species richness at single sites was 32–43% higher, and the beta diversity component rose by 43–51%. These impacts of DNA barcoding on measures of richness reflect its capacity to reveal cryptic species that were overlooked in the first study. The overall results confirmed unique diversity patterns reported in the first investigation. Species diversity was uniformly high along the gradient, declining only slightly above 2800 m. Species turnover also showed little variation along the gradient, reinforcing the lack of evidence for discrete faunal zones. By confirming these major biodiversity patterns, the present study establishes that incomplete species delineation does not necessarily conceal trends of biodiversity along ecological gradients, but it impedes determination of the true magnitude of diversity and species turnover.

Caterpillar assemblages on Chusquea bamboos in southern Ecuador: abundance, guild structure, and the influence of host plant quality

“…The elevational species turnover between the two forest types was very high, with only 4.0% of species shared between sites, emphasising the highly distinct Lepidoptera communities between the lower montane rain forest and the elfin forest. Such high turnover rates in Lepidoptera communities along elevational gradients are well known from tropical mountain regions (Brehm & Fiedler, ; Axmacher et al ., ; Novotny et al ., ; Brehm et al ., ). More than half of all species were found only as singletons, which is a common pattern in studies dealing with plant‐feeding insects in tropical rain‐forest ecosystems (Basset & Kitching, ; Novotny & Basset, ; Novotny et al ., ) and most probably caused by undersampling owing to the necessary restriction of sampling effort to reasonable limits (Coddington et al ., ).…”

“…For species delimitation, we applied the ‘Barcode Index Number (BIN) system’ (Ratnasingham & Hebert, ). This method has been confirmed as a robust first approach for species delimitation in butterflies (Huemer et al ., ) and moths (Hausmann et al ., ; Zahiri et al ., ), and is particularly useful in areas where taxonomic knowledge is incomplete (Brehm et al ., ). In Table S1, we provide a list of all observed taxa including information about their collection site, and, if available, their ‘Barcode Index Number’ (BIN).…”

Revision of the genus Callipia Guenée, 1858 (Lepidoptera, Geometridae), with the description of 15 new taxa

“…The BIN system allows a quick and reliable assignment of DNA-barcoded specimens. This is particularly valuable in cryptic and difficult species complexes in poorly known faunas (Brehm et al 2016). Assignment of DNA barcodes to described species was performed by careful comparison of type material with freshly collected material (Brehm 2015;Brehm et al 2016), and all relevant types and vouchers are illustrated in this paper.…”

“…This is particularly valuable in cryptic and difficult species complexes in poorly known faunas (Brehm et al 2016). Assignment of DNA barcodes to described species was performed by careful comparison of type material with freshly collected material (Brehm 2015;Brehm et al 2016), and all relevant types and vouchers are illustrated in this paper. DNA-barcoded material also includes six old specimens collected between 30 and 100 years ago in a couple of cases where no fresh material was available (Strutzenberger et al 2012).…”

From writing to reading the encyclopedia of life

“…It can also provide new details on host-parasitoid interactions [107], on pollination syndromes [108,109] and on symbiotic associations [110,111]. Aside from revealing interactions, DNA barcoding allows the assessment of biodiversity on scales [112] and in settings where this would otherwise be impossible [113]. By exploiting its capacity to improve species recognition and to reveal their interactions, DNA barcoding is also providing new details on food web structure [114][115][116][117].…”