Eustrotiinae

Keegan, Kevin L., Rota, Jadranka, Zahiri, Reza, Zilli, Alberto, Wahlberg, Niklas, Schmidt, B. Christian, Lafontaine, J. Donald, Goldstein, Paul Z. & Wagner, David L., 2021, Toward a Stable Global Noctuidae (Lepidoptera) Taxonomy, Insect Systematics and Diversity (AIFB) 5 (3), pp. 1-24 : 12

Eustrotiinae

The Eustrotiinae have been recognized as a polyphyletic amalgam (e.g., Fibiger and Lafontaine 2005) of small to very small noctuids, united by few if any characters other than size and loss or reduction of the anterior prolegs. Most are brightly colored or otherwise boldly marked; some are entirely or facultatively diurnal. Attempts to identify autapomorphies for the group have been thwarted by the highly heterogeneous composition of the subfamily ( Kitching and Rawlins 1998). The 28 genera included by Hodges et al. (1983) for the fauna of North America north of Mexico have since been parsed among 10 subfamilies. Lafontaine and Schmidt’s (2010) checklist did much to restrict the concept of the subfamily, reducing the number of genera in North America north of Mexico to just 14.

We found that members of genera Capis Grote, 1882 ; Deltote R.L. [Reichenbach], 1817 (= Eustrotia ); Maliattha Walker, 1863 ; Marimatha Walker, 1866 ; Ozarba Walker, 1865 ; and Protodeltote Ueda, 1984 are correctly placed in Eustrotiinae (BS = 85, SH = 99.5, UF = 81; Fig. 3 ), but four other eustrotiine genera grouped elsewhere. Cerathosia Smith, 1887 , formerly Eustrotiinae incertae sedis, was reassigned to Stiriinae by Wagner et al. (2019), a finding we confirmed ( Fig. 4 ). Another Eustrotiinae incertae sedis genus, Neotarache Barnes & Benjamin, 1922 , clustered within Condicinae ( Fig. 5; see Condicinae ). The two largest New World genera that had been recognized in Eustrotiinae , Cobubatha and Tripudia , grouped apart from Eustrotiinae with the Old World genus Aucha ( Fig. 3 ; see Cobubatha clade above).

Species in the genera we found to group in Eustrotiinae are generally external grass ( Poaceae ) or sedge ( Cyperaceae ) feeders as larvae, with reduced or missing prolegs on A3 and A4 and trisetose SV group on A1 ( Crumb 1956, Wagner et al. 2011). Like most other noctuids, adults have large bullae (also known as countertympanal cavities), which are air-sacs in the dorsoanterior part of the abdomen that likely act as resonators for the ear ( Speidel et al. 1996).

Previous concepts of the subfamily, especially with the largely desert-dwelling species of Cobubatha and Tripudia included, suggested that Eustrotiinae were most species-rich in deserts and semi-arid habitats. Our trimmed set of genera argues that the taxon is better thought of as one of mesic grasslands and wetlands. We caution that the taxa we had available for sequencing may not be valid representatives of their respective genera. For example, we have reason to believe that Ozarba , with 208 described species ( Poole 1989), is polyphyletic, with its members representing two or more different noctuid subfamilies (we have yet to sample the type species, O. punctigera Walker, 1865 , found in Indomalaya and Australia).

Figures

Fig. 3. Maximum-likelihood tree inferred by RAxML analysis. Clade labels reflect our hypotheses about the extent of the various clades, and the taxonomic changes suggested in Results and Discussion. Lineages shown as being members of various clades may not have as yet been transferred into them. Bootstrap values ≥ 70 are shown at nodes.The scale bar shows estimated number of substitutions per site.The tree continues into Figs. 4–6. Clades are shown in three alternating colors to aid visibility.

Fig. 4. Continuation of maximum-likelihood tree inferred by RAxML analysis.