1. MALE GENETALIA OF
MAJOR INSECT ORDERS
CHRYSTINA ALLIEN XAVIER
KERALA AGRICULTURAL UNIVERSITY
COLLEGE OF AGRICULTURE, VELLAYANI
1
2. INTRODUCTION
• The external reproductive organs of the male are concerned in
coupling with the female genitalia and with the intromission of
sperm. They are known collectively as the male genitalia.
• Male genital morphology typically exhibit patterns of highly
divergent evolution.
• There is considerable variation in the terminology used in
describing the genitalia in different orders and problems in
homologizing the different structures.
2
3. MALE GENITALIA
The primary function of the male genitalia in insects is insemination of the
female.
Methods of achieving insemination involve special functions of external
genitalia including;
clasping and holding the female,
retaining the connection with the female gonopore,
the construction of spermatophores, and
the deposition of spermatophores or semen into the female genital tract;
in some insects the injection of semen takes place directly into the female
body (traumatic insemination of some Hemiptera). Other functions of the
male genitalia include excretion and various sensory functions
3
4. • The basic elements are derived from a pair of primary phallic lobes
which are present in the posterior ventral surface of segment 9 of the
embryo.
4
5. • They may represent ancestral penes rather than appendages of
segmental origin. These phallic lobes divide to form an inner pair of
mesomeres and outer parameres, collectively known as the
phallomeres.
5
6. • The mesomeres unite to form the aedeagus; the intromittent organ. The
inner wall of aedeagus continuous with the ejaculatory duct ;
endophallus & opening of the duct at the tip of aedeagus; phallotreme
6
7. • The gonopore is internal, but in many insects the endophallic duct is
eversible and so the gonopore assumes a terminal position during
copulation.
• Parameres develop into claspers; variable in form.
7
8. Male genetalia of hexapoda having paired gonopores:
PROTURA
• Bipartite intromittent organ eversible from
between the sternal plates of the 11th and 12th
abdominal segments.
• The distal part of genital organ ends –pair of
hollow processes – 2 genital ducts opens
separately through subterminal apertures
(Gprs).
• On 9th abdominal segment
8
9. THYSANURA
• Consists of an unpaired median
intromittent organ and paired lateral
accessories.
• In Machilidae and Lepismatidae the
intromittent organ is a simple
tubular median penis, or phallus
arising from the membrane behind
the narrow membranous venter of
the ninth abdominal segment.
• The organ; proximal part/
phallobase (Phb) & distal part/
aedeagus (Aed). 9
10. • Closely associated with the penis
are the appendages of the ninth
segment, which are well developed
in the Thysanura.
• Each genital appendage, or
gonopod, consists of a large, flat
coxopodite (Copd) and of a slender
distal stylus (Sty)
• Certain species of Machilis have
also a pair of smaller anterior
gonapophyses arising at the
corresponding angles of the
coxopodites of the eighth segment
(A, 1Gon).
10
11. • Male Archaeognatha and Thysanura have terminal segments similar to
those in females, but with a median phallus which is bilobed in
Thysanura.
• In these groups, sperm are not transferred directly to the female
11
12. General Structure of the Male Genitalia of
Pterygote Insects
• The primary external genital organs of male pterygote insects are located
medially on the venter of the ninth abdominal segment.
• This segment, therefore, is the male genital segment, or gonosomite.
• Accessory genital structures, however, may be present on the periphery of
the genital segment or on the pregenital or post genital segments.
12
13. • The genital parts, therefore, can be classed in two distinct groups of
structures.
one group constitute the median intromittent apparatus of the ninth
segment; the phallic organs.
the peripheral accessory structures of the ninth or other segments;
termed collectively the periphallic organs.
• The phallic organs are immediately concerned with the function of
coition; include the phallus and various supporting structures
• The periphallic organs are movable or immovable lobes or processes-
grasping or clasping role during copulation.
13
15. ODONATA
• There is development of a secondary
copulatory organ on the anterior part of
the abdomen
• The true gonopore of the male (C, Gpr)
is situated on a rudimentary penis of the
ninth abdominal segment concealed
beneath two small plates (e), which
possibly represent the gonopods.
• A large post genital plate (f) appears to
be a secondary sclerotization of the
intersegmental area behind the genital
organ.
15
16. • The functional intromittent organ
of the Odonata is a secondary
structure situated in a median
depression on the ventral wall of
the second abdominal segment (A,
Pen)
• This organ is a strongly sclerotized
tubular structure
• Various accessory lobes (A, a, b)
arise from the sur-rounding walls
of the first and second abdominal
segments
• Copulatory organ contains a
chamber open to the exterior
which serves as a sperm receptacle
16
17. ORTHOPTERA
• The external genitalia of male
Orthoptera are mostly phallic
structures.
• The coxopodites of the styli are
plates distinct from the ninth
sternum in Grylloblattidae (A,
Cxpd), but otherwise the genital
coxopodites are united with the
sternum in the definitive sternal plate
of the ninth abdominal segment.
17
18. • In Mantidae and Blattidae the male
organs consist typically of three phallic
lobes surrounding the gonopore,
contained in a genital chamber between
the ninth sternum and the paraprocts (E).
• Of the three phallomeres, two are
situated above the gonopore, one to the
left (E, F), the other to the right (G),
while the third (H) lies ventral to the
genital opening.
• The ventral lobe (H) is usually more
simple, and, since the ejaculatory duct
(Dej) opens in a membranous fold at its
base (Cpr),it is often called the "penis."
18
19. COLEOPTERA
• The male genitalia in Coleoptera, as
in Orthoptera, are phallic structures
only, there being in general no
accessory or periphallic armature on
the genital segments.
• The ninth and tenth segments of the
abdomen are usually much reduced
and retracted into the eighth segment,
and in some forms the eighth is
concealed within the seventh.
19
20. • The phallic organs consist essentially
of a tubular aedeagus and a variously
developed phallobase usually
provided with parameres.
• Within the eighth segment is an
invagination cavity (B, a) into which
are retracted the reduced ninth and
tenth segments, but which is
continued forward through the
narrow annulus as a large genital
chamber (GC) containing the phallic
organs (Phl).
• The tenth segment(X) appears as a
small projection from the dorsal wall
of the entrance chamber, bearing the
anus (An).
20
21. • The phallic organs arise from the
anterior wall of the genital chamber
(Phl).
• The aedeagus (C, D, Aed) is
typically a sclerotic tube with a
membranous distal part (Vsc); from
its base an apodeme (D, Apa)
projects into the body cavity
beneath the apodeme of the
phallobase.
21
22. HEMIPTERA
• In addition to well-developed phallic organs,
various periphallic structures having the form
of lobes or processes arising from the eighth,
ninth, and tenth abdominal segments.
• Movable claspers; the harpagones as
derivatives of the styli of the gonopods of the
ninth segment.
• In Homoptera, arise from the floor of the
genital chamber, where their bases are usually
associated with one of the sclerites of the
phallobase or supporting plates of the aedeagus
• In Heteroptera, the harpagones are small but
strongly musculated processes articulated to the
sclerotic wall of the ninth segment inflected
into the genital chamber.
22
23. • The principal segment involved in the genital modification of the
hemipterous abdomen is the ninth but in heteroptera the eighth is often
reduced and closely associated with the ninth.
• The phallus of the Hemiptera comprises in most cases a phallobase
and an aedeagus, though either one or the other may be suppressed.
23
24. • The aedeagus in its simplest
development is a tubular structure (E,
Aed), but more usually it takes on an
irregular shape may produce bizarre
forms, often with curious terminal
outgrowth (D, g).
• It is usually provided with apodemal
processes for muscle attachment (D, h,
i).
• The phallobase is variously developed.
It may consist merely of one or two
basal plates in the wall of the genital
chamber (E, F,1BP, 2BP) supporting
the aedeagus (Aed) and giving
attachment to phallic muscles.
24
25. LEPIDOPTERA
• The genital complex of male
Lepidoptera includes the eighth, ninth,
and tenth abdominal segments.
• The eighth segment forms at least a
protractile base for the copulatory
apparatus (H), and in some cases it
bears accessory genital lobes. The ninth
segment may be a simple sclerotic ring
(H, IX), but usually it is irregular in
form, with distinct tergal and
coxosternal areas of sclerotization.
• The tergum (IXT) is the tegumen of
lepidopterists, and the coxosternal arc
the viniculum.
• The tenth segment may be a simple
membranous tube(H X) 25
26. • Movable genital claspers (the harpes of
lepidopterists) are characteristic of the
male genitalia of Lepidoptera and
assume a great variety of forms (D, H, 1,
Hrp).
• The phallic organs of the Lepidoptera
include an aedeagus (Aed), usually an
eversible endophallic tube often of much
greater length than the aedeagus (F,
Enph), and various supporting structures
that may be referred to the phallobase.
• In its simplest development the
phallobase is a mere inflection of the
genital chamber wall forming a pocket
(phallocrypt) containing the base of the
aedeagus; but the lips of the pocket may
be produced as a tubular theca (D,The)
more or less enclosing the aedeagus
26
27. HYMENOPTERA
• The male genitalia of Hymenoptera appear
to be phallic structures only, periphallic
appendicular organs being absent in most
cases
• The phallus is usually a large, highly
complex structure(C, D) arising from the
wall of the genital chamber above ninth
sternum (A).
• It consists of a central aedeagus (C, D Aed)
often provided with lateral or terminal
processes, and of a large two-segmented
phallobase (Phb) bearing various lobes and
processes surrounding the aedeagus.
• The proximal segment, or basal ring
(cardo"), of the phallobase (BR) opens
from the body cavity by a large foramen(D)
that gives passage to the ejaculatory duct 27
28. • The more lateral ventral pair (C,
D, G, Pmr)may be termed
parameres
• Aedeagus is a relatively simple
structure.
• In the Pteronida (C, D, Aed) it is
mostly membranous but contains
two lateral plates (E, F, d)
produced proximally as
apodemes on which the aedeagal
muscles are attached (E, G).
• In the honey bee the entire phallic
organ is much simplified; the
basal structures of other
Hymenoptera are absent, and the
organ appears to consist of the
aedeagus with a highly developed
eversible endophallus. 28
29. DIPTERA
• The male genitalia of Diptera show a great
proclivity toward the development of
secondary lobes and processes, both phallic
and periphallic.
• In the more generalized families the genital
segments have a tendency to form a terminal
enlargement (hypopygium) of the abdomen
(A)
• In higher families the distinction between
the genital and visceral regions of the
abdomen becomes accentuated by a
reduction of the sixth and seventh segments
and a close association between the eighth,
ninth, and tenth segments to form a genital
complex(F), which becomes mostly
concealed within the fifth segment (E).
• Asymmetry is of frequent occurrence in the
genital region, and the ninth segment is
sometimes partly revolved upon its axis or
completely inverted.
29
30. • The phallic organs of Diptera consist
principally of a variously developed
aedeagus, though supporting basal
structures also may be present.
• The aedeagus in its simpler form varies
from a short tapering process (C, Aed) to
a long slender tube usually curved or
coiled.
• The typical muscoid aedeagus is a large
irregular structure (J, Aed) with basal,
lateral, and ventral lobes or processes.
• Phb is represented by a low thecal fold
surrounding the base of the aedeagus, in
the walls of which are two small plates
(p) supporting a large basal apodeme (A
pb) for muscle attachments. 30
