Larval and pupal descriptions for the genera Podischnus and Heterogomphus (Scarabaeidae: Dynastinae: Oryctini)
Author
Moreno, Jhon César Neita
Author
Orozco, Jesús
text
Zootaxa
2009
2168
34
44
journal article
10.5281/zenodo.189152
3f5939b6-1a02-44ad-a36d-49fefb9424db
1175-5326
189152
Podischnus agenor
(Olivier)
This is the first species in the genus
Podischnus
to have its immature stages described. The descriptions are based on three third-instar larvae, two exuviae from third-instar larvae, and
2 pupae
associated with adults (
Fig. 1
) with the following data:
COLOMBIA
: Choco:
Lloró
, Granja Universidad Tecnológica del Chocó; 5º30.52'52''N;
76º44'33.33''W
;
90 m
; in rotten wood of
Cedrela odorata
L.;
18 November 1998
.
Description of third-instar larva
. Dorsal body length
85–101 mm
(
Fig. 2
a).
Head
(
Figure 2
b).
Cranium
: Width
10–12 mm
. Surface reddish brown, finely punctate; 4 dorsoepicranial setae, 25 epicranial setae distributed irregularly, 11–12 paraocellar setae on each side. Ocelli present. Frontal suture and clypeofrontal suture distinct.
Frons
: 1 exterior frontal seta, 1 posterior frontal seta on each side; 4–5 setae on each anterior angle.
Clypeus
: Form trapezoidal. Postclypeus reddish brown, well sclerotized, densely punctuate; preclypeus light brown, with 2 central setae and 2 lateral seta on each side.
Labrum
: rugopunctate, slightly asymmetrical, 8 posterior setae, 4 lateral setae on each side, 2 central setae.
Antennae
: with 4 antennomeres, antennomere 2 and 3 about 1/4 times longer than antennomere 1 and 4; antennomere 4 slightly longer than antennomere 1. Antennomere 4 oval in dorsal and ventral view, almond-shaped in lateral view; dorsal surface with 10–11 sensory spots (
Fig. 2
c); ventral surface with 9 sensory spots (
Fig. 2
d).
Epipharynx
(
Fig. 2
e): suboval, asymmetrical, left lateral edge angulate. Haptomeral process prominent, entire; right chaetoparia with 95 setae; left chaetoparia with 82 setae, with some sensilla; acroparia each with 21 straight, long, thick setae; corypha with 4 fine, long setae; acanthoparia with 12–13 short, curved, spine-like setae; pedium large, ovate. Dexiotorma elongate, narrow; laeotorma slightly shorter than dexiotorma. Dexiophoba absent; laephoba poorly developed between haptolachus and inner side of laeotorma, with 24 fine setae. Sclerotized plate of right nesium long, elongate, and truncate at apex; sense cone on left nesium represented by longitudinal, wellsclerotized plate, apex with 4 sensilla. Crepis poorly defined.
Maxillae
(
Fig. 2
f): cardo subrectangular. Stipes longer than wide. Galea with many stout setae and 1 well-developed uncus at apex. Lacinia with many stout setae and 3 unci fused at their bases (
Fig.
2
g). Maxillary palpi with 4 palpomeres, all palpomeres of different lengths, palpomere 4 twice as long as palpomere 2. Stridulatory area with 10 blunt, truncate ridges and an anterior truncate process (
Fig. 2
h).
Hypopharynx
(
Fig.
2
i): Glossa with 50 fine, long setae and 34 stout, short setae. Hypopharyngeal sclerome asymmetrical, concave medially, sharp process produced dorsally; left and right lateral lobes with 38 fine, moderately long setae. Left margin with row of 12 stout, moderately long setae directed toward center of sclerome and 3 basal setae at sclerome.
Right mandible
: apical tooth blade-like, S1 + S2 fused, S3 rounded after scissorial notch; scrobe with 16 fine, long setae. Ventral surface (
Fig. 2
j) with elongate-oval stridulatory area formed by 34 narrowly separated ridges; ventral process well developed, rounded, with many asperites. Dorsal surface (
Fig. 2
k) with line of 12 fine, long setae. Brustia with 6 long, stout setae. Calx large, with 11 basolateral setae. Molar area with 3 wide, convex, ridged lobes (M1-3) and with 9 long, fine setae.
Left mandible
: scissorial region with 4 teeth, basal tooth separated from S1-S3; S1 and S2 separated from S3 by scissorial notch. S3 and S4 notched. Scrobe with 14 long, fine setae. Dorsal surface (
Fig. 2
l) with line of 17 fine, moderately long setae; acia well developed, sharp, setae at apex absent, with 12 basolateral setae. Ventral surface with elongate-oval stridulatory area formed by 31 narrowly separated ridges (
Fig.
2
m); ventral process well developed, rounded, with many asperites; dorsomolar area with row of 12 stout, fine, moderately long setae; brustia with 14 stout, long setae arranged in form of a “U”. Molar area with 3 lobes, first molar lobe (M1) large.
Thorax
. Pronotum irregularly and weakly sclerotized, with 8 long, fine setae. Prothoracic spiracles (
Fig. 2
n)
0.69 mm
long,
0.49 mm
wide; respiratory plate dark brown, bulla prominent; distance between respiratory lobes less than diameter of bulla; plate with 46 holes across diameter at middle, holes with irregular edges (
Fig. 2
o). Dorsum of prothorax with transverse row of 38 long, fine setae. Mesoprescutum with transverse, irregular row of 28 long, fine setae and 24 short, spine-like setae; metaprescutum with 32 long, fine setae; metascutellum with 22 long, fine setae and 40 short, fine setae; spine-like setae absent.
Legs
: Tarsal claws with enlarged apical process, 1 basoexternal seta and 1 internal, preapical seta (
Fig. 2
p). Tarsal claw on protarsi larger than claws on mesothoracic and metathoracic legs. Coxae, trochanter, and tibiotarsi of all legs setose, setae fine or stout.
Abdomen
. Abdominal spiracle I
0.57 mm
long,
0.38 mm
wide, shorter than spiracles II–VIII. Spiracles on segments II and VI equal in size,
0.57 mm
long,
0.42 mm
wide; spiracles on segment VII slightly wider than preceding (
0.57 mm
long,
0.49 mm
wide). Abdominal segment I with 21 long, fine setae on prescutum, 42 short, fine setae; subscutum with 18 long, fine setae; scutum with 8 long, fine setae, 18 short, fine setae, 13 short, spine-like setae; scutellum with 8 long, fine setae, 32 short, fine setae. Abdominal segment II on prescutum with 22 long, fine setae and 42 short, fine setae; subscutum with 18 short, fine setae; scutum with 8 long, fine setae, 18 short, fine setae, and 13 short, spine-like setae; scutellum with 8 long, fine setae, 32 short, fine setae. Abdominal segment III on prescutum with 18 long, fine setae, 62 short, fine setae, and 22 short, spine-like setae; subscutum with 51 short, fine setae; scutum with 10 long, fine setae, 102 short, fine setae and 46 short, spine-like setae; scutellum with 12 long, fine setae, 112 short, fine setae, and 89 short spine-like setae. Spiracular area with 61 long, fine setae. Abdominal segment IV on prescutum with 18 long, fine setae, 12 short, fine setae and 116 short, spine-like setae; subscutum with 58 long, fine setae and without short, spine-like setae; scutum with 18 long, fine setae, 165 short, fine setae and 126 short, spine-like; scutellum with 12 long, fine setae, 186 short, fine setae, and 168 short, spine-like setae. Spiracular area with 61 long, fine setae. Abdominal segment V with 18 long, fine setae, 196 short, fine setae, and 202 short, spine-like setae on prescutum; subscutum with 51 short, fine setae; scutum with 16 long, fine setae, 116 short, fine setae, and 226 short, spine-like setae; scutellum with 12 long, fine setae, 212 short, fine setae, and 109 short, spine-like setae. Spiracular area with 61 long, fine setae. Abdominal segment VI on prescutum with 22 long, fine setae, 122 short, fine setae, and 201 short, spine-like setae; subscutum with 56 short, fine seta and without short, spine-like setae; scutum with about 126 long, fine setae, 198 short, fine setae, and 198 short, spine-like setae; scutellum with about 10 long, fine setae, 118 short, fine setae, and 179 short, spine-like setae. Spiracular area with 61 long, fine setae. Abdominal segment VII with 2 rows of setae (anterior and posterior), each with 2 long, fine setae, 186 short, fine setae, and 28 short, spine-like mixed. Spiracular area with 61 long, fine setae. Abdominal segment VIII with 2 rows of setae, anterior row with 2 long, fine setae; posterior row with 4 long, fine setae, and 216 short, fine setae mixed. Spiracular area with 58 long, fine setae. Abdominal segment IX with one anterior row of 2 fine setae, and a posterior row with 4 long, fine setae mixed with 216 short, fine setae. Spiracular area with 58 long, fine setae. Abdominal segment X with approximately 124 moderate to long, fine setae and 391 short, spine-like, mixed setae. Spiracular area with 58 long, fine setae. Pleural lobes with 48 long, fine setae; short setae absent.
Raster:
without palidia; campus with 18 long, fine setae; teges with 125 short setae projecting toward superior anal lobe; barbula with 35–36 long, fine setae. Anal slit transverse.
FIGURE 2.
Podischnus agenor
third-instar larva. a. larva, lateral view; b. head; c. dorsal view of antennomere 4; d. ventral view of antennomere 4; e. epipharynx; f. maxilla; g. maxillar unci; h. maxillar stridulatory area; i. hypopharynx; j. right mandible, ventral view; k. right mandible, dorsal view; l. left mandible, dorsal view; m. left mandible, ventral view; n. respiratory plate; o. respiratory plate holes; p. tarsal claw.
Description of pupa
. Male (
Fig. 3
). Length
38.3 mm
. Width at pronotum
18.6 mm
. Body shape elongate, oval, stout. Color dark reddish orange. Entire body covered with fine, velvety-gold vestiture.
Head
. Glabrous, bent sharply beneath thorax; antennae, labrum, mandibles, maxillae and palpi discernible; antennal tecae expanded, stout, with rounded apex. Compound eyes sunken, scarcely visible. Frontoclypeus with strong, wide, massive horn; apex broadly rounded.
Thorax
. Pronotum: glabrous, anteromedial tubercle with rounded apex. Elytral and posterior wing tecae closely appressed, curved ventrally around body; elytral tecae extending to middle of abdominal segment IV; posterior wing tecae extending to middle of abdominal segment V. Protibia with 3 distinct teeth on external edge. Mesotibiae and metatibiae with inner and external spines well developed at apex.
FIGURE 3.
Podischnus agenor
pupa. a. ventral view; b. lateral view; c. dorsal view.
Abdomen
. Segments III–X well defined in ventral view. Segment VII slightly longer than preceding segment, VIII 0.25 times longer than segment VII; segments VIII and IX fused. Segment X with small and slightly prominent genital ampulla. Segments I–X with well-defined dioneiform organs in dorsal view, sclerotized between segments I–VII. Pleural lobes rounded. Spiracle I elongate, with fine peritreme and covered by wing thecae; spiracles II–IV ovate, prominent, with strongly sclerotized peritreme; spiracle V–VIII closed. Abdominal apex rounded, with fine and short setae.
Female. As male except in the following respects: Length
38.2 mm
. Width at pronotum
15 mm
.
Head
. Without tubercle.
Abdomen.
Segment X without genital ampulla.
Remarks
. The following characters will separate the larvae of
P
.
agenor
from other Neotropical dynastine larvae: anterior frontal setae and posterior frontal setae present; laeophoba with 24 short, fine setae; stridulatory area with 10–11 blunt, truncate ridges; antennomere 4 with 10 dorsal sensory spots; spiracles on abdominal segments I–IV similar in size; spiracles on segments VII–VIII larger than those on preceding segments.
Natural History
. Adults have been primarily collected at lights at night. They have been observed flying between 20:00 – 05:00. The adults had been taken between March, when the first rains start, through July. The males excavate a gallery in a stalk of
Bambusa guadua
H. & B. (
Poaceae
) or sugarcane (
Eberhard 1979
). Mating occurs inside the stalk. Both beetles exit when mating is over. The larvae have been observed feeding in dead, rotten wood of
Cedrela odorata
L. (
Meliaceae
). The pupal stage lasts from January to March. The life cycle is of one year (
Neita
et al
. 2006
).
Distribution
.
Podischnus agenor
is distributed from
México
to
Ecuador
(
Endrödi 1976
,
1985
;
Ratcliffe 2003
). This species is found in
Colombia
in forest areas from the sea level to
1600 m
.