Anthurium (Araceae)
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Bleiweiss, Nogales Trujillo et. al., 2019 First Observations of Butterfly (Pedaliodes: Satyrinae: ... First Observations of Butterfly (Pedaliodes: Satyrinae: Nymphalidae) Visits to a Wild Anthurium (Araceae) Robert Bleiweiss1,2 [email protected] Angélica Sofía Nogales Trujillo2 [email protected] Thomas B. Croat3 [email protected] César Garzón Santomaro2 [email protected] 1Department of Integrative Biology and the Zoological Museum University of Wisconsin, Madison WI 53706 2Instituto Nacional de Biodiversidad (INABIO) Avenida de Los Shyris (Parque La Carolina) y Pasaje Rumipamba (Boulevard de las Flores) N. 341 Quito, Ecuador 3Missouri Botanical Garden P.O. Box 299 St. Louis, MO 63166–0299 USA ABSTRACT recently discovered at 2700 m in upper Aroids are visited by a diverse assortment montane cloud forests on the eastern slope of animals, including many arthropods and of the Andes in northern Ecuador, some birds. It is therefore surprising that advanced understanding of butterfly-aroid reports of butterflies visiting aroids are associations in several important respects. limited to plants grown in Botanical Over approximately five weeks, two species Gardens or in cultivation. Thus, the role of of Pedaliodes (Satyrinae, Nymphalidae) butterflies in the biology of wild aroids repeatedly visited both female-phase and remains unclear. Observations at Anthurium male-phase inflorescences under a variety bustamanteae (Croat et al. 2020), a species of weather conditions. The butterflies were Aroideana VOL 42 NOS 2&3, 2019 139 Bleiweiss, Nogales Trujillo et. al., 2019 First Observations of Butterfly (Pedaliodes: Satyrinae: ... observed to pick up pollen and feed at fluid time period. Thus, it is not surprising that secretions with their proboscises while they aroid visitors or pollinators include groups perched along male-phase spadices. One or as different as arthropods (e.g. bees, beetles, both Pedaliodes species also formed apparent and flies (Gibernau 2003, 2011, 2016; Prieto feeding queues of up to three individuals & Cascante-Marín 2017) and birds (e.g. seeking to access a fluid-rich zone on the hummingbirds, flowerpiercers, tanagers; male-phase spadix. More direct interference Kraemer & Schmitt 1999; Bleiweiss et al. competition over the surface of the spadix 2019). Butterflies combine attributes of was expressed as aggressive dominance over these attendants, and therefore seem likely butterflies by a wasp, which actively chased to visit aroid as well. However, associations butterflies around the spadix. Evidence that between free-flying butterflies and aroids Pedaliodes visit aroids even when they were completely unknown until recently, experience costs (weather, aggression, when several individuals of the common competition) and benefits (potentially and widespread nymphalid, the Anna’s 88 nutritious aroid secretions) of exploiting butterfly Diaethria anna (Guérin-Méneville), aroids in the wild suggests a dependable were observed feeding at inflorescence ecological relationship. These data confirm fluids of Anthurium podophyllum (Cham. & an earlier report that butterflies are poised Schltdl.) cultivars in Costa Rica. During to provide pollination services to aroids, and these visits the butterflies picked up pollen that nymphalid butterflies in particular may on their proboscises and abdomens and have a special ecological relationship with attended both female-phase as well as male- Araceae, including Anthurium. phase inflorescences (Hartley et al. 2017). With this one exception, however, all other documented association between butterflies KEY WORDS and aroids are of a hodgepodge of captive Ecuador, Montane, Cloud Forest, species housed together in Botanical Mutualism, Pollination, Red Coloration, Gardens (e.g. Suvák 2015). Spadix, Wasp While studying Anthurium bustamanteae (Croat et al. 2020), a species recently INTRODUCTION discovered in upper montane cloud forests The pollination systems of Araceae remain along the eastern slope of the Ecuadorian poorly documented despite intensive studies Andes, two nymphalid butterflies in the into the family’s biological systematics genus Pedaliodes were observed to repeatedly (Croat 1980; Chartier et al. 2013; Gibernau visit its inflorescences. Observations made 2016). Inflorescence design in most aroids intermittently over five weeks allowed us to presents few physical barriers to the flower- characterize the association with respect to bearing spadix, which typically emerges whether butterfly visits: 1) occurred under from the bract-like spathe over a protracted entirely natural (wild) conditions; 2) were of Aroideana VOL 42 NOS 2&3, 2019 140 Bleiweiss, Nogales Trujillo et. al., 2019 First Observations of Butterfly (Pedaliodes: Satyrinae: ... Figure 1. Typical basking behaviors of Pedaliodes asconia (A) and P. phaedra (B) around Guango Lodge, revealing differences in dorsal wing surface coloration. Among possible traits of Pedaliodes that facilitate montane living are their thick hairy bodies, dark coloration, and sun basking. Both species folded their wings when visiting A. bustamanteae (see Figure 2), which suggests they were not visiting the plant to thermoregulate. This difference reinforces the interpretation that butterflies were visiting the plants to feed. sufficient frequency and duration to suggest eastern slope of the Ecuadorian Andes. a strong ecological relationship; 3) resulted Anthurium bustamanteae is a member of in contact with plant sexual structures and section Cardiolonchium (Croat et al. 2020), exploitation of nutritive fluids; 4) could lead and is characterized by its large and striking to mutualisms between butterflies and red spathe and spadix. Floral development aroids. The resulting insights provide followed the typical pattern for the genus, important steps towards understanding the with dichogamous and protogynous sexual role of butterflies in aroid biology and vice staging, resulting in asynchronous versa. development of inflorescences within and among individual plants (Bleiweiss et al. 2019). Macrophotography suggested that MATERIALS AND METHODS floral sexual phases did not develop Study Site and Anthurium Biology.- concurrently on the same spadix, and that Observations were made intermittently male-phase flowers developed in time and between February 26 and March 29, 2017 at space from the base to the tip of the spadix 2700 m in upper montane cloud forests (see Figure 1 in Bleiweiss et al. 2019). Thus, around Guango Lodge (0°22’46.56’’ S, pollination of A. bustamanteae is likely to 78°04’36.12’’ W), which is located occur only by inter-spadix transfers. approximately 4.8 km west of the larger town of Cuyuja, in Napo Province on the Aroideana VOL 42 NOS 2&3, 2019 141 Bleiweiss, Nogales Trujillo et. al., 2019 First Observations of Butterfly (Pedaliodes: Satyrinae: ... As detailed elsewhere (Bleiweiss et al. identifications were made by comparing our 2019), inflorescences of A. bustamanteae photographs of wild butterflies both with produce fluids that appeared to be individuals identified in on-line photographs attractants for various arthropod (wasps, taken at Guango Lodge, and with specimens thrips) and bird (four species of housed in the collections of the Museum of hummingbird and one passerine, a Natural Sciences (MECN) in the National flowerpiercer) visitors. The fluids on Biodiversity Institute (INABIO), Quito. The female-phase inflorescences appeared as species with uniformly black upper wing distinct droplets over the entire spadix, each surfaces was identified as P. asconia Thieme droplet being associated with a female- (Figure 1A), and the one with pairs of large phase flower (stigmatic fluid). By contrast, white bands (forewings) or spots fluid secretions by male-phase (hindwings) on upper wing surfaces was inflorescences are more copious, especially identified as P. phaedra Hewitson (Figure in a “transition zone” where new male- 1B). phase flowers are opening. Although the sugar or caloric content of any of these Observations were made while conducting fluids was not analyzed, the behaviors of other studies, so our data probably visitors suggest that these fluids have underestimated the extent to which nutritive value (Bleiweiss et al. 2019; herein). butterflies visit A. bustamanteae. However, Moreover, analysis of the fluid secretions of overall patterns were consistent across the male-phase inflorescences for a related study period, suggesting that they portrayed species also visited by birds, A. sanguineum, the relationships accurately during this time. indicated appreciable glucose levels (up to In addition, extended watches and digital 12%) in standing crops (Kraemer and photographs were used to document Schmitt 1999). Thus, we consider interesting behaviors. The latter were inflorescence fluids secreted by either sexual captured with a Canon f5.6 55–250mm phase of A. bustamanteae to be potentially zoom lens fitted to a Canon EOS Digital nutritious for the butterflies, while Rebel T5i camera set to ISO 400, AI Servo refraining from any further characterizations AF Mode, auto white balance, and sRGB (e.g. as “nectar”). color space. All photos were taken by Robert Bleiweiss. Visitors.- Both butterfly species observed to visit A. bustamanteae were members of Pedaliodes (Satyrinae: Nymphalidae). These small to medium-sized butterflies are typical denizens of higher elevation habitats throughout the Andes, but are often very similar in appearance and challenging to identify (Pyrcz et al. 2016). Species-level