Pollinia removal and suspected pollination of the endangered ghost orchid, Dendrophylax lindenii (Orchidaceae) by various hawk moths (Lepidoptera: Sphingidae): another mystery dispelled

  • Mark William Danaher U.S. Fish and Wildlife Service
  • Carlton Ward, Jr. Florida Wild
  • Lawrence W. Zettler Illinois College
  • Charles V. Covell, Jr. McGuire Center for Lepidoptera & Biodiversity, Florida Museum of Natural History, University of Florida

Abstract

The ghost orchid, Dendrophylax lindenii (Lindl.) Bentham ex Rolfe (Orchidaceae), is a rare, leafless epiphyte restricted to forests in southernmost Florida and western Cuba. The species’ appealing floral display, high public profile, and challenging cultivation contribute to its ongoing removal from the wild by unethical collectors. To effectively conserve this and other native orchids that rely on seed for reproduction, a thorough understanding of natural pollination mechanisms is essential. Digital single lens reflex camera traps were used to survey for potential pollinators visiting D. lindenii flowers on the Florida Panther National Wildlife Refuge during the summers of 2016 to 2018. Based on suspected D. lindenii pollinia affixed to photographed moths, we provide visual evidence that D. lindenii is pollinated by at least 2 large hawk moths (Sphingidae) in southern Florida, which include the fig sphinx moth, Pachylia ficus Linnaeus, and pawpaw sphinx moth, Dolba hyloeus Drury (both Lepidoptera: Sphingidae). Species that were documented probing D. lindenii flowers, but lacked pollinia, included the giant sphinx moth (Cocytius antaeus Drury), banded sphinx moth (Eumorpha fasciatus Sulzer), and streaked sphinx moth (Protambulyx strigilis Linnaeus) (all Lepidoptera: Sphingidae). In addition to the aforementioned species of hawk moths (sphinx moths), the seagrape spanworm moth (Ametris nitocris Cramer; Lepidoptera: Geometridae), palamedes swallowtail (Papilio palamedes Drury; Lepidoptera: Papilionidae), monk skipper (Asbolis capucinus Lucas; Lepidoptera: Hesperiidae), Brazilian skipper (Calpodes ethlius Stoll; Lepidoptera: Hesperiidae), and 3 unidentifiable geometrid moths were observed visiting D. lindenii flowers within the study area. During 2017 and 2018, a total of 21 different visits by Lepidoptera were recorded, and the duration of each visit was rarely longer than 1 s. Hawk moth visits were infrequent, but did show some evidence of clustering by species. Measurements of proboscis lengths of the 2 documented pollinators from museum specimens were of sufficient length (50–100 mm) to probe D. lindenii nectar spurs, further lending support to our field observations. Larval food sources of the 2 confirmed pollinators include plant species native to southern Florida, suggesting that these moths are natural pollinators of D. lindenii. Our findings, although preliminary, provide critically needed baseline information that will augment ongoing conservation efforts in southern Florida aimed at the recovery of D. lindenii.

 

Resumen

La orquídea fantasma, Dendrophylax lindenii (Lindl.) Bentham ex Rolfe (Orchidaceae), es una rara epífita sin hojas restringida a los bosques en el extremo sur de Florida y el oeste de Cuba. La atractiva exhibición floral de la especie, su alto perfil público y su difícil cultivo contribuyen a su eliminación permanente de los recolectores no éticos. Para conservar de manera efectiva esta y otras orquídeas nativas que dependen de la semilla para la reproducción, es esencial comprender a fondo los mecanismos naturales de polinización. Se utilizaron trampas fotográficas digitales réflex de lente única para inspeccionar posibles polinizadores que visitan flores de D. lindenii en el Refugio Nacional de Vida Silvestre Florida Panther durante los veranos de 2016 para 2018. Sobre la base de la sospecha de D. lindenii polinios pegada a polillas fotografiadas, proporcionamos evidencia visual de que D. lindenii es polinizada por al menos 2 polillas halcón grandes (Sphingidae) en el sur de la Florida, que incluyen la polilla esfinge, Pachylia ficus Linnaeus y la papaya Esfinge polilla, Dolba hyloeus Drury (ambos Lepidoptera: Sphingidae). Las especies documentadas que probaron las flores de D. lindenii, pero carecían de polinios, incluían la polilla esfinge gigante (Cocytius antaeus Drury), la polilla esfinge bandada (Eumorpha fasciatus Sulzer), y la polilla esfinge rayada (Protambulyx strigilis Linnaeus) (todo Lepidoptera: Sphingidae). Además de las especies antes mencionadas de las polillashalcón (polillas esfinge), la polilla de la lombriz (Ametris nitocris Cramer; Lepidoptera: Geometridae), cola de golondrina del paladar (Papilio palamedes Drury; Lepidoptera: Papilionidae), patrón del monje (Asbolis capucinus Lucas; Lepidoptera: Hesperiidae), skipper brasileño (Calpodes ethlius Stoll; Lepidoptera: Hesperiidae), y se observaron 3 polillas geométridas no identificables visitando flores de D. lindenii dentro del área de estudio. Durante 2017 y 2018, se registraron un total de 21 visitas diferentes de Lepidoptera, y la duración de cada visita rara vez fue superior a 1 s. Las visitas de la polilla halcón fueron poco frecuentes, pero mostraron cierta evidencia de agrupamiento por especies. Las mediciones de la longitud de la probóscide de los 2 polinizadores documentados de especímenes del museo fueron de una longitud suficiente (50–100 mm) para sondear los espolones de néctar de D. lindenii, lo que brindó más apoyo a nuestras observaciones de campo. Las fuentes de alimento larvales de los 2 polinizadores confirmados incluyen especies de plantas nativas del sur de Florida, lo que sugiere que estas polillas son polinizadores naturales de D. lindenii. Nuestros hallazgos, aunque preliminares, brindan información de línea de base crítica y necesaria que aumentará los esfuerzos de conservación en curso en el sur de la Florida dirigidos a la recuperación de D. lindenii.

Key Words: Florida Panther National Wildlife Refuge; Fakahatchee Strand; conservation

View this article in BioOne

Author Biographies

Carlton Ward, Jr., Florida Wild

Carlton Ward Jr is a conservation photographer and National Geographic Explorer whose passion for nature was born from the Florida landscape. His mission is to inspire appreciation and protection of Florida’s original nature and culture – the endangered wildness that is often hidden in plain sight but very much needs our attention to be saved.

Lawrence W. Zettler, Illinois College

Hitchcock Professor of Biology

Charles V. Covell, Jr., McGuire Center for Lepidoptera & Biodiversity, Florida Museum of Natural History, University of Florida

Currator of Moths, McGuire Center for Lepidoptera & Biodiversity, Florida Museum of Natural History, University of Florida, Gainesville, FL 32611 USA

Published
2020-02-02
Section
Research Papers