Cacographis (Lederer, 1863) of Costa Rica feeding on Araceae: species identity, biology, and larval description (Lepidoptera: Crambidae)

Authors: Solis, Maria; VARGAS ALVARADO, JAVIER - Universidad De Costa Rica; PHILLIPS-RODRIGUEZ, E. - National Museum Of Costa Rica; HALLWACHS, W. - University Of Pennsylvania; JANZEN, D. - University Of Pennsylvania

Submitted to: Proceedings of the Entomological Society of Washington
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/22/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary: Many species in the arum plant family are grown for food or cultivated for their ornamental leaves worldwide. Recently, caterpillars of a group of snout moths were reared on taro for the first time in Costa Rica. Historically, these caterpillars have been intercepted at U.S. ports on the same plant family, and although the host plant occurs in southeastern United States members of this moth group have not been reported to occur in the U.S. Because the caterpillars are internal feeders, we describe the caterpillars and the external damage they cause for the first time. We coin a new common name for a species, the taro snout moth. Nomenclature is usually based on adults only, so the morphological identity of Central American species was determined, and one subspecies was elevated to species rank. As a result of recent additional material and unraveling of the classification, we now report three species of this group in Costa Rica instead of one. This information will be useful to taro growers in the Western Hemisphere and U.S. quarantine personnel at U.S. ports.

Technical Abstract: The recent discovery of larvae as stem and petiole miners in Colocasia esculenta var. esculenta Schott (Araceae) in Costa Rica provided the impetus for the study of Cacographis Lederer in Central America. Adults were reared and identified as Cacographis osteolalis osteolalis (Lederer, 1863), the taro snout moth (newly coined here). Because most of the feeding is internal, external reactions by the plant are described and illustrated for diagnosis in taro plantations. Additionally, based on evidence of external morphology, male genitalia, and COI barcodes, we elevate the Central American Cacographis osteolalis azteca Munroe to the rank of species, C. azteca, revised status. In addition to C. undulalis Schaus that is endemic to Costa Rica, two additional taxa, C. azteca, and the nominotypical subspecies, C. osteolalis osteolalis, are also reported to occur in Costa Rica. The larva of the genus Cacographis is described for the first time in the subfamily Midilinae, a member of the “wet habitat clade” in the Crambidae (Regier et al. 2012). The larvae have bisetose lateral setae on the prothorax that differ greatly in length, and highly modified abdominal segments eight and nine, with spiracles for respiration facing posteriorly that have not been reported elsewhere in the Pyraloidea. Cacographis larvae are compared to those of Midila Walker, and images of the larval morphology are provided.