Diabrotica bioculata Bowditch

Species name

Diabrotica bioculata Bowditch 1911: 16

Type locality

Jalapa, Mexico

Type depository

MCZ, lectotype, male, verified

Synonyms

peckii Bowditch 1911: 53 (type locality: Brit. Honduras, Manatee Dist.; type depository: MCZ, holotype, male, verified)

Diagnosis

Body length 5.8-6.8 mm. Body width 3.0-3.3 mm. Head basic color black. Antennae filiformfiliform:
slender antennae with antennomeres of similar shape
, male antennae with thickened antennomeres 4-6, bi- or tricolored, antennomeres 1-3 uniformly sulphur yellow or yellow with darkened upper side, antennomeres 4-8 uniformly cinnamon brown, antennomeres 9-10 uniformly yellow ocher or yellow, partly infuscateinfuscate:
darken with a brownish tinge
, sulcatesulcate:
bearing the carinae or ridges on the elytron
,1 completely dark (cinnamon brown). Maxillary palpi black, piceous or amber brown, labrumlabrum:
the "upper lip" of beetles, a movable sclerite joined under clypeus
black. Pronotumpronotum:
the notum of the prothorax with highly sclerotized pronotal disc
yellow, mustard yellow or sulphur yellow, subquadrate, weakly bifoveate with wide shallow foveae, shagreened with minute wrinkles. Scutellumscutellum:
small, usually triangular shield between the bases of elytra
yellow or yellow ocher. Basic color of elytra yellow or rufous, with 2-3 black bandsbands:
(here) transverse maculae on the beetle elytra
, anterioranterior:
the nearest to the front of beetle
bands connected into ring-shape maculae. Posteriorposterior:
the region of the body parts of the beetle furthest from the head
maculae oculate or shapeed as opened rings. Epipleura completely yellow, Elytra not sulcatesulcate:
bearing the carinae or ridges on the elytron
, sutural anglesutural angle:
the posterior angle or apex of the elytron near the suture
round, punctation scattered, fine. Abdomen yellow. Tarsi and tibiatibia:
<em>(pl. tibiae)</em> the forth part of the beetle leg articulated with femur on the one side and with tarsus on the other side
black or amber brown, femora uniformly yellow. Internal sac with five scleritessclerites:
(here) the sclerotized hooks, spines or plates in the internal sac
.

Known distribution

Mexico, Belize, Costa Rica

Host plants

Unknown

Remarks

Bowditch (1911) indicated the differences between D. bioculata and D. peckii being slightly different coloration of antennae and elytrae, pronotumpronotum:
the notum of the prothorax with highly sclerotized pronotal disc
foveation and elytrae punctation. All these features are subject of substantial variation within the same species. We studied the internal sac of aedeagusaedeagus:
the main sclerotized part of the male genitalia; "aedeagus" is used here instead of "median lobe of aedeagus"
in the types of both species. No substantial differences were found in the internal sac armament. Both type specimens are very similar in the external features. Hereby we treat D. peckii as synonym of D. bioculata.

Potential problems with identification

Diabrotica bioculata is very similar to many of the "oculate" species such as D. gratiosa Baly, D. adelpha Harold, D. biannularis Harold, D. pulchella (Jacquelin-du-Val). Diabrotica bioculata, the closest species to D. biannularis, can be well separated by tibiatibia:
<em>(pl. tibiae)</em> the forth part of the beetle leg articulated with femur on the one side and with tarsus on the other side
color, which are brown or black in D. bioculata. Diabrotica pulchella can be separated by the same feature, since its tibiatibia:
<em>(pl. tibiae)</em> the forth part of the beetle leg articulated with femur on the one side and with tarsus on the other side
are yellow. The pronotumpronotum:
the notum of the prothorax with highly sclerotized pronotal disc
in D. adelpha is nonfoveate, but bifoveate in D. bioculata. Pronotumpronotum:
the notum of the prothorax with highly sclerotized pronotal disc
and elytrae in D. adelpha are more convex than in D. bioculata. The shape of the internal sac scleritessclerites:
(here) the sclerotized hooks, spines or plates in the internal sac
allows distinguishing D. bioculata from all other species too. Sclerite 5A is quite remarkable, it is a narrow flat plate, widened and toothed apically, bearing extremely long, bent, pointed hook basally.