Dieffenbachia oerstedii Schott (Araceae), 1858

Hernández-Ortiz, V. & Aguirre, A., 2015, A new species of the Neotropical genus Beebeomyia (Diptera: Richardiidae) with observations of its biology on Dieffenbachia oerstedii (Araceae), Journal of Natural History 49, pp. 1-13 : 2-3

Dieffenbachia oerstedii Schott (Araceae)

In Mexico, D. oerstedii may be confused with D. wendlandii Schott and D. killipii Croat because they have similar blade shape ( Croat 2004; Acebey and Krömer 2008). Herbarium material of D. oerstedii may also be confused with D. seguine (Jacq.) Schott , from the West Indies and the Amazon region. It is an herb usually less than 50 cm in height, (ranging from 30–75 cm), distributed from southern Mexico to Panama. In the Los Tuxtlas region (Veracruz, Mexico) it occurs from 100 to 1100 m above sea level ( Acebey and Krömer 2008). Flowering occurs throughout the year; however, there are two main periods, one in April at the beginning of the dry season and a second peak during September, at the end of the rainy season; each individual presents one to three inflorescences, or, rarely, four ( Croat 2004). The inflorescence, which consists of a spathe with male and female flowers, is dicogamous (protogynous), and is pollinated by beetles of the genera Cyclocephala and Erioscelis (Scarabaeidae) ( Cuartas-Hernandez and Nuñez-Farfán 2006).

Biological samples

During the peak flowering season of Dieffenbachia oerstedii (September of 2013), infestation rates and feeding habits of a richardiid fly species that was found associated with the developing inflorescences were evaluated. In the field, we observed the female oviposition behaviour, and developing inflorescences were collected for further examination. Under laboratory conditions (temp 24°C ± 4; and RH 70% ± 10), we kept the inflorescences individually in plexiglass cages with permanent moisture at the base. Each inflorescence was measured for length and width, and later it was dissected lengthwise to locate any larvae and/or pupae, recording the particular sites where immature stages were found feeding. The pupae were kept in plastic rearing chambers until adult emergence. Adult specimens were preserved and dry-mounted; the abdomens of some specimens were also excised to study the terminalia of both sexes. The genitalia were processed in a 10% sodium hydroxide (NaOH) solution by heating for 10 minutes, subsequently washed with distilled water, placed in plastic microvials with glycerine and pinned under the rest of the specimen. Digital photographs for D. oerstedii were taken with a Nikon D5100 (18–55 VR, lenses king CU+1, +2, +4, 52 mm) camera, and the images of Beebeomyia specimens were taken with an Olympus C5050 camera, adapted to Olympus SZX7 and BX41 microscopes. The morphological terminology of flies used in this paper is based on Cumming and Wood (2009). The material examined was deposited in the following entomological collections: Instituto de Ecología AC (INECOL), Xalapa, México (IEXA); Colección Nacional de Insectos, Instituto de Biología – UNAM (CNIN); the Estación de Biología Tropical Los Tuxtlas – UNAM (EBLT); and the National Museum of Natural History (USNM).

Data analyses

To evaluate the infestation levels by immature stages found inside the inflorescences of D. oerstedii , we calculated the means and standard error (mean ± SE). Wilcoxon tests were used for comparing infestation levels by fly species, and between sexual sections of the inflorescences ( Zar 2010). Statistical analyses were performed using Statistica software 7.1 (StatSoft, Inc. 2006).