Response to Heethoff, Norton, and Raspotnig: Ant and Mite Diversity Drives Toxin Variation in the Little Devil Poison Frog and Erratum

Abstract

Our recent publication titled "Ant and Mite Diversity Drives Toxin Variation in the Little Devil Poison Frog" aimed to describe how variation in diet contributes to population differences in toxin profiles of poison frogs. Some poison frogs (Family Dendrobatidae) sequester alkaloid toxins from their arthropod diet, which is composed mainly of ants and mites. Our publication demonstrated that arthropods from the stomach contents of three different frog populations were diverse in both chemistry and species composition. To make progress towards understanding this trophic relationship, our main goal was to identify alkaloids that are found in either ants or mites. With the remaining samples that were not used for chemical analysis, we attempted to identify the arthropods using DNA barcoding of cytochrome oxidase 1 (CO1). The critique of Heethoff, Norton, and Raspotnig refers to the genetic analysis of a small number of mites. Here, we respond to the general argument of the critique as well as other minor issues detailed by Heethoff, Norton, and Raspotnig.

How Phylogenetics Can Elucidate the Chemical Ecology of Poison Frogs and Their Arthropod Prey

“…Characterization of the chemical defenses of mites is also hindered by the status of mite taxonomy and dearth of mite taxonomists, an uncontroversial point made by McGugan et al (2016b). The number of oribatid mites is on a par with ants (roughly 14,000 species); Schatz et al (2011) reported 16,197 extant species of oribatid mites.…”

“…They attempted to identify the arthropod species (ants and mites) responsible for the alkaloid diversity in the little devil poison frog, Oophaga sylvatica, by coupling molecular phylogenetic identi cation of prey with characterization of alkaloids both in the prey and in the skin of the predator frog. McGugan et al (2016b) retrieved 137 ants and 102 mites from the stomachs of frogs of three populations of O. sylvatica. Here we focus only on the mites.…”

“…McGugan et al faced swift criticism of their novel approach from a group of mite experts (Heethoff et al 2016, hereafter Heethoff et al) Heethoff et al also argued that CO1 was inadequate for identi cation, given the paucity of mite species for which CO1 sequences were available, and that traditional morphological methods of identi cation would have been more e cacious. McGugan et al (2016b) responded that their species identi cations were tentative and that the primary goal had been not to identify species as alkaloid sources but rather to pro le the diet of geographically diverse populations O. sylvatica. They also stated that not every arthropod consumed by poison frogs was likely to contribute to their alkaloid repertoire.…”