Staminodeus vectoris, Nico M. Franz, 2001

Nico M. Franz, 2001, Description And Phylogeny Of Staminodeus, A New Genus Of Derelomini (Coleoptera: Curculionidae) Associated With Cyclanthaceae, The Coleopterists Bulletin 55 (4), pp. 411-432 : 427

Staminodeus vectoris , new species

Diagnosis. Staminodeus vectoris is distinguished from S. dilatatus by the higher number of smaller, arcuate dentes in males, in addition to differing from S. bispinosus and S. forcipis by the glabrate frons. Males and females were associated by field observations (see below).

Male. Length 1.6–2.3 mm, width 0.7–1.0 mm, l/ w 2.1 –2.4. Rostrum 0.4–0.5 mm, r/p 0.7–0.9. Frons glabrate. Pronotum l/ w 0.8 –1.0, convex. Prosternum longer than mesosternum. Profemur ( Fig. 3g ) slightly arcuate, f/p 0.9–1.2, width similar throughout, ventrally denticulate; protibia ( Fig. 3g ) subrectate, t/f 0.9–1.2, anteroventral margin with row of 6–10 apically directed, arcuate dentes, apically mucronate, promucron nearly 2/3 as long as protarsal claw; mesotibia apically mucronate, mesomucron nearly 1/4 as long as mesotarsal claw. Elytron l/ w 1.3 –1.6 (N 15). Wing/body 1.2–1.3, wing l/ w 3.0 –3.4 (N 8). Median lobe ( Fig. 4g ) l/ w 2.5 –3.3 (N 15), laterobasal sclerites apically setose, median sclerite basally projected, apically bifurcate, setose, apical rami undulate, apically spatulate, basal 3/4 of median lobe denticulate, aedaegal apodemes shorter than median lobe.

Female. Length 1.8–2.2 mm, width 0.8–1.0 mm, l/ w 2.1 –2.4. Rostrum 0.5 mm, r/ p 0.8–1.1, laterobasal 1/3 carinulate. Frontal spine nearly 3/5 as long as diameter of eye. Pronotum l/ w 0.8 –1.1 (N 15). F/p 0.9–1.2; t/f 0.8–1.0. Elytron l/ w 1.4 –1.6 (N 15). Wing/body 1.2–1.3, wing l/ w 3.0 –3.4 (N 8). Spermatheca ( Fig. 5g ) deflexed nearly 135, apex rotundate.

Type Information. Male holotype ‘‘ Costa Rica, Heredia, La Selva , 40 m, on Asplundia uncinata, leg. N. Franz, VII­03–1997 ’’ ( MUCR) ; female allotype, same label as male holotype ( MUCR) ; male paratypes, same labels as male holotype (AMNH, 5; BMNH, 5; CMNC, 5; CWOB, 5; INBC, 5; MIUP, 5; MUCR, 5); female paratypes, same labels as male holotype (AMNH, 5; BMNH, 5; CMNC, 5; CWOB, 5; INBC, 5; MIUP, 5; MUCR, 5).

Etymology. Named for the female behavior of transporting the detached staminodes (see below)— vectoris signifying ‘‘carrier’’ ( Brown 1956).

Distribution. Staminodeus vectoris has been collected at the Volcán Arenal in Costa Rica, Provincia Alajuela, Los Lagos: 10 29 N, 84 43 W; on the Carribean slope of Costa Rica, Provincia Heredia, Parque Nacional Braulio Carrillo, La Selva and Rara Avis; in the Central Valley of Costa Rica, Provincia San Jose ´, Zurquí de Moravia; and on the Carribean slope of Panama, Provincia Bocas del Toro, Río Changuinola ( Fig. 6 ).

Natural History. Staminodeus vectoris is associated with the staminodes of the inflorescences of Cyclanthaceae . At La Selva, both sexes visit several species of Asplundia Harling , Carludovica Ruíz & Pavón , Chorigyne R. Eriksson , Dicranopygium Harling , and Evodianthus Oersted. The following observations were made for the most part on Asplundia uncinata Harling. The adult beetles arrive at dawn during the pistillate anthesis when the floral fragrances are volatilized. The females detach the staminodes and fall to the floor where they transport them with their legs—by turning upside down and using the frontal spine to support their position against the surface underneath. Meanwhile, the males associate with the moving staminodes. If several males occur on the same staminode, short fights are observed during which the prothoracic legs are used to displace competing males with fast blows. Presumably, the dentate protibiae interlock and translate the lifting power among them. Copulation and oviposition occur above the forest floor; the reproductive behavior is described with more detail in Franz (1999, in prep.). The ephemeral staminodes serve as an oviposition substrate. The larvae are detritivores in the leaf litter, and the pupae emerge from the forest floor after 10–20 days. The adult beetles are not pollinators because they do not touch the pistillate flowers of the host inflorescence and leave before the staminate anthesis. Staminodeus vectoris was coded (by C. W. O’Brien) as ‘‘gen. C 2 sp. C1’’ in Franz (1999).

Figures

Fig. 3. Staminodeus, male, right profemur and protibia, anterior view, a) S. inermis; b) S. curvitibialis; c) S. denticulatus; d) S. bispinosus; e) S. forcipis; f) S. dilatatus; g) S. vectoris. Scale bar 0.1 mm.

Fig. 4. Staminodeus, male, aedeagus, ventral and lateral view, a) S. inermis; b) S. curvitibialis; c) S. denticulatus; d) S. bispinosus; e) S. forcipis; f) S. dilatatus; g) S. vectoris. Illustrations are interpretative: denticulation and setation are omitted. Scale bar 0.1 mm.

Fig. 5. Staminodeus, female, spermatheca and gland reservoir, a) S. inermis; b) S. curvitibialis; c) S. denticulatus; d) S. bispinosus; e) S. forcipis; f) S. dilatatus; g) S. vectoris. Scale bar 0.05 mm.

Fig. 6. Distribution of Staminodeus in Costa Rica, Panama, and Venezuela, S. bispinosus; S. curvitibialis (distributional record for Colombia, Provincia Nariño, La Planada is omitted); S. denticulatus; S. dilatatus; S. forcipis; S. inermis; S. vectoris.