Libethra rabdota ( Westwood, 1859 )

Murcia, Andres David & Cadena-Castañeda, Oscar J., 2023, The stick insects (Insecta: Phasmatodea) from the Cloud Forest of the Chicaque Natural Park, Colombia, Insecta Mundi 2023 (20), pp. 1-45 : 4-10

Libethra rabdota ( Westwood, 1859)

( Fig. 1–8 )

Diagnosis. Species with marked sexual dimorphism. Male. Body yellow and thin ( Fig. 1A–B ). Head unarmed and flat vertex ( Fig. 1C ); antennae reaching the VI tergite. Pronotum and metanotum smooth ( Fig. 1C ), mesonotum with small lateral spines ( Fig. 1B ). Abdomen smooth ( Fig. 1A ). Legs ornamentations variable, from armed with small spines or unarmed ( Fig. 1B ). Tergite X divided into two lobes by a midline running through it; poculum firmly tectiform with the posterior margin elongated, convex, and slightly elevated (Fig. E–G).

Female. Body brown and more robust than the male ( Fig. 2A–B ). Head armed with two very prominent foliose structures ( Fig. 2C ), antennae reaching tergite IV ( Fig. 2A–B ). Thorax with variable ornamentations, with several granules or tubercles, and spines with tubercles varying in length, the mesonotal ones larger ( Fig. 2B ). Abdomen with tergites III–VIII with small posterolateral extensions. Tergite III with prominent foliose structure. Tergite IV–V with a smaller foliose structure located on the posterior margin. Tergite VII has a foliose structure larger than in tergites IV and V and less conspicuous than in tergite III ( Fig. 2A–B ). Legs armed with numerous foliose structures that vary in size ( Fig. 2A–B ). Subgenital plate does not project beyond the apex of the abdomen, becoming gradually narrower towards its apex, where it ends in two points and is centrally excavated ( Fig. 2E–G ). Measurements (mm). ♂ / ♀ TL: 33–35 / 36–37, Pr: 2–2.5 / 3–3.2, Ms: 8–9 / 8–10, Mt: 4–4.2 / 4–4.5, Pf: 10–11 / 9–10, Mf: 8–8.2 / 7–8, Hf: 11–12 / 10–10.5, Pt: 11–11.2 / 10–10.5, Mt: 7–8.5 / 7.5–8, Ht: 11–12 / 11–12, Ant: 29–29.5 / 24–27.

Eggs. Dark brown and slightly shiny, with a cream-colored region surrounding the collar and extending dorsally around the micropylar plate. Rough capsule ( Fig. 3 ), 1.8 times longer than wide and 1.6 times longer than tall, semi-ellipsoidal in shape, dorsal surface progressively narrowing towards the posterior polar zone, ovoid operculum with numerous hairs wholly surrounded by the collar, inserted in an angle of 35° ( Fig. 3B–C ). Micropylar plate anterior to the central region, ovoid with a prominent margin, slightly laterally compressed in the posterior region, inner part smooth ( Fig. 3A ). Micropylar cup small, extending beyond the posterior margin of the micropylar plate. The midline is faint and does not reach the polar zone ( Fig. 3A ).

Measurements (mm). Length: 3, capsule height: 1.5, capsule width: 1.2, operculum diameter: 1.

Coloration variation. Male. With variable coloration, as described below: 1. Body completely dark brown ( Fig. 4A ). 2. Light green body ( Fig. 4B ). 3. Ocher-colored body ( Fig. 4C ). 4. Light brown with yellow legs ( Fig.5A ). 5. Light brown with small irregular green spots on the integument ( Fig. 5B ). 6. Dark brown body with a longitudinal yellow dorsal line extending from the pronotum to the tergite X ( Fig. 5C ). Female. 1. Brown body with spines and green leafy extensions. ( Fig.6 ). 2. Body with different shades of brown ( Fig. 7A–B ). 3. Gray body ( Fig. 7C ), some individuals may present combinations of these colors and exhibit different dorsal and longitudinal lines ( Fig. 7A, D ).

Distribution. Widely distributed, in Colombia has been recorded in the departments of Antioquia 1305–2269 m, Cundinamarca 1914 m, Quindío 1800 m, Risaralda (Pereira) and Caldas 1040–2592 m, Cauca, Risaralda, Chocó ( Conle et al., 2011).

Comments. This species has a wide distribution from the Andean region to the Chocó Biogeographic region in Colombia. As it is a wingless species with little dispersal capacity, possibly the specimens from the different localities are not the same species. Additional studies of the individuals from the different mountain ranges as well as from Chocó are required to be able to delimit their taxonomic entities. A couple was seen copulating, and the male had the phallic complex completely exposed ( Fig. 8 ).

Specimens and eggs examined. 5 males and 9 females: 3♂ 1 ♀ 4°36′31″N 74°18′25″W. 2496 m. 14 January 2017; 2♂ 3♀. 4°36′36″N 74°18′26″W. 2409 m. 15 January 2017; 2 ♀. 4°36′43″N 74°18′34″W. 2237 m. 28 January 2017; 3♀. 4°36′29″N 74°18′34″W. 2367 m. 12 September 2020. 15 eggs examined. ( CAUD) .

Figures

Figure 1. Libethra rabdota (Male). A–B) Habitus in lateral and dorsal view. C–D) Head and pronotum in lateral and dorsal view. E–G) Terminalia in lateral, dorsal, and ventral views, respectively.

Figure 2. Libethra rabdota (Female). A–B) Habitus in lateral and dorsal view. C–D) Head and pronotum in lateral and dorsal view. E–G) Terminalia in lateral, dorsal, and ventral views, respectively.

Figure 3. Libethra rabdota. Eggs. A) Dorsal view. B) Ventral view. C) Anterior pole.

Figure 4. Libethra rabdota. Live males, color variation. A) Entirely dark brown body. B) Light green. C) Ocher.

Figure 5. Libethra rabdota. Live males, color variation. A) Light brown with yellow legs. B) Light brown with slight irregular green spots on the tegument. C) Dark brown body with a longitudinal yellow dorsal line that extends from the pronotum to the X tergite.

Figure 6. Libethra rabdota. Live female. Brown coloration with spines and green leafy extensions.

Figure 7. Libethra rabdota. Live females, color variation. A–B) Body with different shades of brown. C) Gray body. D) Some individuals may present combinations of these colors and exhibit different dorsal and longitudinal lines.

Figure 8. Libethra rabdota in copulation.