The document discusses the pheromone production system in insects, emphasizing their reliance on chemical signals for communication. It outlines various types of pheromones, their biosynthesis, and the role of specific glands in their production and release. Additionally, it highlights the mechanisms involved in pheromone signaling and the importance of chemical diversity across different insect species.

1. PHEROMONE PRODUCTION
SYSTEM IN INSECT
PRESENTED BY
P.MANIKANDAN
II M.Sc(Ag)Entomology
Chaiman: Dr.R.Kannan
Assistant Professor in Entomology
Annamalai university

2. COMMUNICATION
• Exchange of information between individuals
2

3. INSECT
COMMUNICATION
3
• Insects – also
communicate - but
their "language“ is
congenital.

4. METHODS OF COMMUNICATION
AUDITORY VISUAL
OLFACTION TACTILE
4

5. OLFACTION (CHEMICAL)
• Insects rely more heavily on chemical signals
than on any other form of communication.
• Semiochemicals or infochemicals
• Serve as a form of "language" that helps to
mediate interactions between organisms
5

6. PHEROMONES
• “PHEROMONE" Karlson and Luscher (1959)
• Greek word
• Phero “to transport”
• Hormone “ stimulate”
• Conspecifics - Elicit innate behaviors
• German biochemist - Adolf Butenandt “BOMBYKOL’’
Butenandt et al. (1961)
6

7. GENERAL CHARACTERIZATION OF
PHEROMONES
Conspecific - Influence the sexual behaviour
Effects are expressed via pheromone-receptors
Signaling is G-protein-linked
Volatile and specificity - Bind with specific PBPs
Excreted in: feaces, urine, sweat and other body-fluids
Determined by MHC-genes
Chemically Diverse - according to species, functions,
action
Mixture of chemicals - Carbons numbers-5 to 20
Molecular weight-17 to 880 g/mol
No.of double bonds 0 to 13
Typical feature-Cis-trans isomerism
7

8. SEX PHEROMONE
LEPIDOPTERA AND
COLEOPTERA
ALARM AND AGGRN
PHEROMONE
APHIDS, BOLL
WEEVIL
8

9. TYPES OF PHEROMONES BASED ON
CHANGES IN
INSECT
FUNCTIONAL
GROUP
NO. OF
COMPOUND
• Primer
• Releaser
• Type-I
• Type-II
• Monocomponent
• Multicomponent
9

10. I. BASED ON CHANGES IN INSECT
10

11. A) PRIMER PHEROMONES
Trigger off a chain of physiological changes in the recipient without
any immediate change in the behavior.
Act through gustatory sensilla
Caste determination and reproduction in social insects.
(Ekerholm and Hallberg, 2005)
11

12. B) RELEASER PHEROMONES
Produce an immediate change in the behavior of the recipient.
• Brood-tending pheromones
• Recruitment pheromones
• Trail-following pheromones
• Territory-marking
pheromones
• Many other
• Sex pheromones
• Aggregation pheromones
• Anti-aggregation
pheromones
• Alarm pheromones
• Egg laying pheromones
12
(Ekerholm and Hallberg, 2005)

13. II. BASED ON FUNCTIONAL GROUP
13

14. A. TYPE I PHEROMONE
 C12-C18 carbon chain with functional groups -
alcohol, aldehyde and acetate
 Biosynthesised from de-novo synthesised fatty
acid.
Used in approximately 75% of moths
Eg. Lepidopteran moths
(Ando and Yamakawa, 2011)
14

15. B. TYPE II PHEROMONE
 Comprising unsaturated hydrocarbons and
their epoxy derivates
 C17–C23 hydrocarbons and epoxides
 orginate from long chain hydrocarbons
produced outside PGs.
 Synthesized in oenocytes or epidermal cells
 Geometridae, Arctiidae and cockroach
(Millar et al. 2005).
15

16. III. BASED ON NUMBER OF COMPONENT
16

17. 1. Monocomponent
• Only one chemical compound
Silkworm – Bombykol - (10E,12Z)-
hexadeca-10,12-dien-1-ol C16H30O
(Morgan and Mandava, 1988)
Lymantria dispar – Disparlure - 2-
methyl-7R,8S-epoxy-octadecane -
C19H38O (Jurenka et al., 2002)
17

18. 2. Multicomponent
More than one chemical compound
• Bark Beetle - ipsenol and ipsdienol
• Pink bollworm - Gossyplure
• Cockroach - Blatellaquinone
18

19. 2. Multicomponent
More than one chemical compound
• Tobacco cutworm - Spodolure, litlure
• Gram pod borer- Helilure
• Honey bee queen- Queen’s substance
19

20. EXOCRINE GLAND’S ASSOCIATION
WITH PHEROMONE PRODUCTION
20

21. Gland associated with pheromone
production
• Exocrine glands - Glands that secrete their
products (excluding hormones and other
chemical messengers) into ducts (duct glands)
which lead directly into the external
environment.
• Exocrine glands contain a glandular portion
and a duct portion
21

22. TYPES OF EXOCRINE GLANDS
Based on
1. Structure
2. Product secreted
3. Presence of reservoir
22

23. I. Based on structure
1.Simple - duct portion may be unbranched
SIMPLE TUBULAR SIMPLE BRANCHED
TUBULAR
2. Compound - duct portion may be branched
SIMPLE ALVEOLAR BRANCHED ALVEOLAR
23
COMPOUND TUBULAR COMPOUND ALVEOLAR COMPOUND TUBULO ALVEOLAR

24. PRODUCTS SECRETED BY EXOCRINE
GLANDS
Glands Location Function
Setal glands Scoli Irritant fluid
Stink glands/
Repugnatorial
glands
Scattered all
over body
Secrete bad smelling
substances (stink
bugs, bed bugs)
Salivary glands Near
hypopharynx
Saliva
Pheromone
glands
Abdomen Secretions are
released outside to
attract opposite sex
Wax glands Abdomen Dermal glands
produce wax in honey
bees
Lac glands Dermal Resinous substance
24

25. Based on presence of reservoir
Epithelial glands without
reservoir (ex) metatibial gland
of ants,
Epithelial glands with
reservoir (ex) frontal gland
of termite soldiers
Bicellular unit glands
without reservoir(ex) tergal
glands of honeybees
Bicellular unit glands with
reservoir(ex) venom gland
of Hymenoptera
Bicellular gland units opening through
intersegmental membrane (ex) Richard’s
glands of epiponine wasps
(Sobotnik et al., 2010).
25

26. ANATOMY OF PHEROMONE
PRODUCING GLANDS AND
DISCHARGE
26

27. 1. BLATTODEA
 Gland located on the anterior of the
last (10th) abdominal tergite called the
pygidium in female German cockroach,
Blattella germanica
 Contents of secretory vesicles from
cells in the gland are transpor ted
through long ducts to the cuticular
sur face for release.
 Newly discovered pheromone is
nicknamed “parcoblattalactone”
(Liang and Schal, 1993)
27

28. 2. COLEOPTERA – CLICK BEETLE
 In female Agriotes lineatus, the sex pheromone accumulates in
opalescent, sacciform glands located in the 7th abdominal
segment
 Discharges geranyl hexanoate and geranyl octanoate
posteriorly into the outer por tion of the oviduct .
(Borg Karlson et al. , 1988)
sacciform glands
28

29. 2. SAP BEETLE - CARPOPHILUS
FREEMANI DOBSON
 Males produce hydrocarbon aggregation pheromone in large
disk-like abdominal oenocytes that occur within the body
cavity.
 These cel ls are connected by tracheae to the integument, with
the pheromone secreted into tracheal -associated ductules
eventually reaching the cuticular sur face of the male through
the spiracles.
(Dowd and Bartelt, 1993; Nardi et al., 1996)
29

30. 3. RED FLOUR BEETLE
 A setiferous patch located
over exocrine glands in the
prothoracic femora of the
male Tribolium castaneum
(Herbst)
The secretion from this
patch was attractive to
both sexes
(Faustini et al., 1982)
30

31. 4. ANT LOVING BEETLE
31
 A glandular organ in the apical (10th and 11th)
antennal segments of the male Batrisodes oculatus
Aube is involved in secreting a female attractant
(de Marzo and Vit , 1983)

32. 32
Drosophila melanogaster Meigen
 The hydrocarbon pheromones synthesized in the
abdominal oenocytes are transported by
lipophorin to epidermal cells for deposition on
the cuticular surface.
(Pho et al., 1996)
3.DIPTERA
The cells in Drosophila melanogaster that
produce pheromones are located in
the abdomen. These 'oenocytes' are
revealed by expression of a protein
fluorescing green

33. 4. Lepidoptera
 Lepidopteran females produce and release sex pheromone
components from bulbous extrudable glands located between
the 8th and 9th abdominal segments
(Bjostad et al . , 1987) .
33

34. SATURNIID MOTH- Hemileuca electra
 Female exposing her pheromone gland, located at the t ip of
her abdomen.
 Such pheromone- rel ea sing b e havio r, te rmed “ c a lling, ”
pheromone gland
34

35. EXCEPTIONS
35
 Spear-marked black moth, Rheumaptera hastata - gland consists
of a pair of internal tubular organs that extend f rom their common
opening in the 9th abdominal segment anteriorly into the 7th
abdominal segment (Werner, 1977)
 Paired tubular glands have been identified f rom the bog
holomelina, Holomelina lamae (Freeman) (Yin et al . , 1991)
 Long, coiled tubular glands are present in the abdominal tip of
female arctiid, Utetheisa ornatrix
(Eisner and Meinwald, 1995) .

36. 5. HYMENOPTERA
HONEY BEE PHEROMONE GLANDS
1.Nasanov gland
2.Koschevnikov gland
3. Dufour’s gland
4.Mandibular glands
36

37. 1.Nasanov gland- Located on the top of
the abdomen closer to the stinger. This
gland puts off an ATTRACTANT
pheromone.
2. Koschevnikov gland- Located near the
sting shaft. The gland produces an
alarm pheromone that is released
when a bee stings
3. Dufour’s gland- located in abdomen.
Secretion is often used in
communication to mark members of the
colony.
4. Mandibular glands- gland is situated
near the ventral base of a mandible
37

38. BIOSYNTHESIS
38

39. De nova BIOSYNTHESIS OF PHEROMONE
FATTY ACID METABOLISM
DESATURATION (DESATURASES)
CHAIN SHORTENING BY Β-OXIDATION
FINAL FUNCTIONAL GROUP MODIFICATION BY
REDUCTION (REDUCTASES)
ACETYLATION (ACETYL TRANSFERASES) OR OXIDATION
PHEROMONE PRODUCT
(Tillman et al., 1999)
39

40. Proposed pathways for lepidopteran
sex pheromones
40

41. Fatty acid synthesis
Elongation
Hydro carbon formation
PHEROMONE
PRODUCTION
(Juarez et al., 1992)
41

42. TYPE-II PHEROMONE BIOSYNTHESIS BLATELLA GERMANICA
42
(Juarez et al. , 1992)

43. Dipteran pheromone biosynthesis
Fatty acid
synthesis
desaturation elongation
reductive
decarboxylation.
Unsaturated
hydrocarbons
epoxides
43
(Wicker and Jallon, 1995; Pennanec’h et al., 1997)

44. HOUSE FLY
(Blomquist et al., 1984; Ahmad et al., 1987)
45

45. PHEROMONE PRODUCTION IN
BOMBYX MORI
Fatty acid synthesis
desaturation
Fatty acyl reduction
bombykol
(Ando et al., 1988)
45

46. ENZYMES INVOLVED IN PHEROMONE
BIOSYNTHETIS
a) Acetyl-CoA carboxylase and fatty acid synthetase
• to make 16 and 18 carbon fatty acids
b) Desaturases
• to make mono- and di unsaturated fatty acids
c) Specific chain-shortening enzymes
• to make the right chain length fatty acid
d) a reductase, an acetyltransferase, or an oxidase is
used, sometimes in combination
46

47. ENDOCRINE REGULATION OF
INSECT PHEROMONE PRODUCTION
• Insects utilize at least three hormonal
messengers to regulate pheromone
biosynthesis
 Juvenile hormone III
 Fatty acyl–CoA elongation enzyme(s)
(elongases)
 Pheromone biosynthesis activating
neuropeptide (PBAN)
47

48. HORMONAL MESSENGERS
48
• Blattodean and coleopteran - Juvenile hormone
III
• Diptera - one or more fatty acyl–CoA elongation
enzyme(s) (elongases)
• Lepidopteran - pheromone biosynthesis
activating neuropeptide (PBAN)
(Barth and Lester, 1973)

49. PHEROMONE BIOSYNTHESIS ACTIVATING
NEUROPEPTIDE (PBAN)
• A polypeptide hormone that controls the
synthesis of the sex pheromone in moths has
been named PBAN
• PBAN is produced in the suboesophageal
ganglion (SOG)
• Transported to the corpora cardiaca (CC) before
its release into the hemolymph
• PBAN acts directly on pheromone gland cells by
using calcium and cAMP (Cyclic adenosine
monophosphate) as second messengers.
49
(Barth and Lester, 1973)

50. Role of PBAN in moths
50
• Red banded leafroller (Argyrotaenia
velutinana) - PBAN regulates pheromone
biosynthesis
• Several moths - PBAN appears to regulate an
enzyme, a Δ 11 desaturase

51. PHEROMONE BLENDING
51

52. PHEROMONE BLENDING
• Survey - Ten lepidopteran species - extracts of
the ovipositor tips - unusual fatty acids that
had the same carbon lengths, double-bond
positions, and stereochemistries as the
acetate, alcohol, or aldehyde pheromone
components for the species
(Wolf et al., 1981).
52

53. 53
PHEROMONE BLEND RATIO REGULATION
Ratio-regulated blends of the different
pheromone components.
• Pyralid moth - Ostrinia furnacalis uses a
sex pheromone blend of (E)- and (Z)-12
tetradecenyl acetate (E12-and Z12-14:OAc)
in a 53:47 ratio
• In the closely related species Ostrinia
nubilalis, that uses a mixture of (E)- and
(Z)-11-tetradecenyl acetate (E11- and Z11-
14:OAc) as its pheromone
(Cheng et al., 1981).

54. How the blend specificity achieved?
• Compounds having different oxygenated functional
groups (aldehydes , acetates, alcohols or ketones)
• Compounds having different numbers of carbons in
the skeleton
• Compounds having different degrees of unsaturation
• Compounds having different geometries of double
bonds
• Blends of compounds having different ratios of the
same components
• Blends of compounds containing different numbers of
components
(Wyatt, 2010)
54

55. HOST COMPOUNDS CONVERSION AS
PHEROMONE
55

56. Douglas-fir beetle
• Monoterpene limonene from host Douglas-fir.
• Douglas-fir beetle release limonene as
respective aggregation pheromone
components.
• Limonene functions as a synergist in
douglas-fir beetle.
• Biosynthesis of terpene-derived
pheromones via modification of host
compounds in the curculionid
• Feeding on host Pinus spp. phloem induces
synthesis of JH III by the corpora allata.
(Rudinsky et al., 1977)
56

57. CONVERSION BY THE MALE ORNATE
MOTH Utetheisa ornatrix
Crotalaria
spectabilis monocrotaline oxidation
57
release hydroxydanaidal
(Conner et al., 1981, 1990;Eisner and Meinwald, 1995)

58. CONVERSION BY FEMALES OF THE SALT
MARSH CATERPILLAR MOTH
Host plant
Linolenic acid
(Z9,Z12,Z15-
octadecatrienoic acid;
Z9,Z12,Z15–18:Ac)
decarboxylated Elongation
C21 alkatriene C21 epoxide
58
(Rule and Roelofs, 1989)

59. CONVERSION BY THE MALE
Ips paraconfusus Lanier
ponderosa pine myrcene
(S)-(+)-ipsdienol
and
(S)-(2)-ipsenol
release
(Hendry et al., 1980)
59

60. PHEROMONE RELEASE
60

61. RELEASING OF PHEROMONE
• Releasing into the environment involve two
separate process:
1. Synthesis
2. Dispersal
• Pheromone producing gland with out reservoir
- directly to dispersal.
• Producing gland with reservoir
- temporally separate.
61

62. PHEROMONE DISPERSAL
• Androconial organs : Present
on male butterflies and moth
which ending in a brush-like
row process.
• Male moths extent
androconia to release
pheromones
(Jason et al., 2003)
62

63. PHEROMONE DISPERSAL
• The hairy appendages are the
everted coremata
e.g Creatonotos gangis
• Ants drags the tip of the
abdomen over the surface as
it runs.
63

64. PHEROMONE DISPERSAL
• Insect curls its body, so the
stored phermone which is in
contact with cuticle will
disperse. E.g. ant (Pachycondyla
tarsata).
• In bumblebee, labial gland
pheromones are transferred to
the vegetation by biting.
• In honey bee colony pheromone
dispersal facilitate by fanner
bees
64

65. PHEROMONE DISPERSAL 65
• Releasing the sex attractant
pheromone-calling.
• Pheromone gland exposed to
outside by
-depressing the tip of the abdomen
-extension of the abdomen
-gland is inverted by haemolymph
pressure
• Exposure of the gland is
accompanied by wing vibration
which facilitate dispersal.

66. CHEMORECEPTORS
• Insects can sense various chemical
substances in their environment.
• Gaseous form they may be detected as
odors.
• Solid or liquid form they are perceived as
tastes by gustatory receptors
• Sense of taste (contact chemoreception)
• Sense of Smell (remote chemoreception)
68

67. Gustatory
receptors
sensory neurons
Each neuron appears to
respond to a different
range of compounds
Most abundant on the
mouthparts, but may also
be found on the antennae,
tarsi, and genitalia
Olfactory
receptors
numerous pores.
Dendrites of sensory
neurons branch profusely
within these pores
Some receptors respond to
a wide range of substances
while others are highly
specific
Most abundant on the
antennae
69

68. OLFACTORY SYSTEM
 Olfactory systems detect and differentiate
odor stimuli
 Olfactory receptor neurons encode
information about odors
 Insect ORNs are distributed in sensilla,
usually in the form of sensory hairs
 Odorants pass through tiny pores in the
walls of these sensilla and stimulate
dendrites bathing in the lymph inside
(Silbering and Benton, 2010)
70

69. PERCEPTION AND SIGNAL PROCESSING
Peripheral perception at the antenna where specialized
sensilla
Odorant molecules diffuse into the lumen of the sensilla
Bound to pheromone binding proteins that solublize the
pheromone in the aqueous receptor lymph
Carry them to specialized receptors on the surface of
dendrites in the sensillum.
71

70. 72
G-protein-mediated activation of phospholipase C and generation of inositol
triphosphate
Inositol triphosphate-gated Ca++ channels in the dendritic
membrane
Electrochemical signal transduction
Pheromone molecules must be degraded rapidly.
(Laissue and Vosshall, 2008)

71. Mechanism of perception
73

72. PHEROMONE BINDING PROTEINS
74
• PBPs - small , globular, water-soluble proteins
• Highly concentrated in the aqueous sensillar lymph
• PBPs are broadly expressed in most olfactory
organs
• PBP binds pheromone with certain selectivity
• Initiating the first biochemical step in odorant
reception (Leal, 2013).
• Transporting hydrophobic sex pheromone across
aqueous sensillar lymph to the surface of olfactory
receptor neurons
(Buck and Axel, 1991; Benton et al., 2006)

73. BEHAVIORAL RESPONSE TO
PHEROMONE
75

74. • Orientation of male moths towards the
female-emitted sex pheromone in a natural
environment.
• Pheromone perception triggers a sustained
upwind flight in male moths (positive
anemotaxis).
• Fluttering in silk worm
• Wing raising behavior in Blattodea germanica
• Increased locomotion in trail-following ants
76

75. Periplaneta americana
 Grooming of antenna in male
 Move upwind
 Increased locomotor activity
Honey bee (Queen Mandibular
Pheromone)
 Retinue
 Swarming
 Mating flight
77

76. FACTORS AFFECTING THE
PHEROMONE PRODUCTION
Temperature Photoperiod
PHEROMONE
PRODUCTION
Host plants Age and mating
78

77. CONCLUSION
• Insects have well defined communication system
which rely more on chemical communication in the
form of pheromones for mate finding and aggregation
• Insects synthesis their own pheromone from the bye
products of metabolic activity especially from fatty
acid metabolism and these reactions are catalyzed by
the enzymes.
• The success rely on the reception by its conspecifics
• These properties of pheromone can be exploited for
attracting the crop pest by formulating and used for
better crop protection
79