Diabrotica trifurcata Jacoby

Species name

Diabrotica trifurcata Jacoby 1887: 522

Type locality

Panama, V. de Chiriqui

Type depository

BMNH, lectotype, male, verified

Synonyms

elegantula Baly 1886b sensu Jacoby 1887: 504 (misidentification)

linensis Bechyné 1956: 260 (type locality: Panama, V. de Chiriqui; type depository: BMNH, lectotype, male, verified)

Diagnosis

Body length 6.1-7.0 mm. Body width 3.2-3.5 mm. Head basic color black. Antennae filiformfiliform:
slender antennae with antennomeres of similar shape
, bi- or tricolored, antennomeres 1-3 uniformly yellow or yellow with darkened upper sides, antennomeres 4 - 8 uniformly cinnamon brown, antennomeres 9 - 10 uniformly sulphur yellow, antennomereantennomere:
"segment" of antenna, more or less clearly separated
11 dark apically. Maxillary palpi black, chestnut or amber yellow, labrumlabrum:
the "upper lip" of beetles, a movable sclerite joined under clypeus
black or chestnut. Pronotumpronotum:
the notum of the prothorax with highly sclerotized pronotal disc
yellow, light cadmium or ochraceous-orange, subquadrate, weakly bifoveate, with wide shallow foveae, not shagreened. Scutellumscutellum:
small, usually triangular shield between the bases of elytra
amber brown. Basic color of elytra yellow or rufous, with 2-3 black bandsbands:
(here) transverse maculae on the beetle elytra
. Bandsbands:
(here) transverse maculae on the beetle elytra
are connected creating two ring-shape yellow maculae on each elytronelytron:
<em>(pl. elytra)</em> the fore highly sclerotized wing of beetle
, or basalbasal:
of or pertaining to the base, as in the first, or basal segment of an appendage; opposite of apical
band positioned on basalbasal:
of or pertaining to the base, as in the first, or basal segment of an appendage; opposite of apical
elytra margin and divided into three branches (two humeral and one sutural), posteriorposterior:
the region of the body parts of the beetle furthest from the head
band is separate in this case and may be reduced to two transverse spots. Color of bandsbands:
(here) transverse maculae on the beetle elytra
metallic black blue. Elytral 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
rounded, punctation scattered, fine. Abdomen yellow or yellow ocher. Tarsi black, chestnut or mars yellow, protibia uniformly black, chestnut or bicolored, yellow, outer edge with piceous or testaceous line or extensively darkened. Meso- and metatibia black or chestnut. Femora yellow or yellow ocher. Internal sac of aedeagusaedeagus:
the main sclerotized part of the male genitalia; "aedeagus" is used here instead of "median lobe of aedeagus"
with five scleritessclerites:
(here) the sclerotized hooks, spines or plates in the internal sac
.

Known distribution

Costa Rica, Panama, Nicaragua, Colombia

Host plants

Unknown

Remarks

Diabrotica elegantula was described by Baly (1886) from Colombia. Jacoby (1887) discussed the similar specimens from Panama and assigned them to Baly's D. elegantula. He cited Baly's description and proposed the figure of D. elegantula. Jacoby indicated that this species is very variable, but did not provide a description of the species. Bechyné (1956) erroneously credited Jacoby with the description of D. elegantula. He treated the Central American specimens as Jacoby's valid species and cited Jacoby's D. elegantula as a primary homonym of the Baly's D. elegantula. Therefore he proposed a new name, D. linensis, for the Central American specimens. In fact, Bechyné proposed the features that allow distinguishing D. elegantula Baly and Central American specimens belonging to D. linensis. Smith and Lawrence (1967) designated lectotype D. linensis from Jacoby's material. We studied the internal sac of the aedeagusaedeagus:
the main sclerotized part of the male genitalia; "aedeagus" is used here instead of "median lobe of aedeagus"
in the types of D. linensis and D. trifurcata and found no significant differences in the internal sac armament. The elytra color pattern in D. trifurcata is undoubtedly the reduced one of D. linensis. No other morphological and habitual differences were found in these two species. Hereby, we treat D. linensis as synonym of D. trifurcata.

Potential problems with identification

Diabrotica trifurcata Jacoby is very similar to D. elegantula Baly, D. gratiosa Baly, D. morosa Jacoby and D. panamensis Jacoby. They can be separated by the following features: the pronotumpronotum:
the notum of the prothorax with highly sclerotized pronotal disc
in D. trifurcata is not shagreened, the color of the bandsbands:
(here) transverse maculae on the beetle elytra
on elytra is metallic blue, in D. elegantula the pronotumpronotum:
the notum of the prothorax with highly sclerotized pronotal disc
is clearly shagreened, the color of the bandsbands:
(here) transverse maculae on the beetle elytra
on elytra is metallic green; femora in D. trifurcata are yellow, but black in D. morosa. The most reliable feature that allows for distinguishing D. trifurcata is the internal sac of the aedeagusaedeagus:
the main sclerotized part of the male genitalia; "aedeagus" is used here instead of "median lobe of aedeagus"
. Sclerite 5E is a flat arcuate plate, toothed apically. This feature allows to distinguish D. trifurcata from all similar species.