PHEROMONE PRODUCTION

SYSTEM IN INSECT

PRESENTED BY

P.MANIKANDAN

II M.Sc(Ag)Entomology

Chaiman: Dr.R.KannanAssistant Professor in EntomologyAnnamalai university

COMMUNICATION• Exchange of information between individuals

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• Insects – alsocommunicate - buttheir "language“ iscongenital.

INSECT COMMUNICATION

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METHODS OF COMMUNICATION

AUDITORY VISUAL

OLFACTION TACTILE

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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

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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)

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GENERAL CHARACTERIZATION OF PHEROMONES

Conspecific - Influence the sexual behaviourEffects are expressed via pheromone-receptorsSignaling is G-protein-linkedVolatile and specificity - Bind with specific PBPsExcreted in: feaces, urine, sweat and other body-fluidsDetermined by MHC-genesChemically Diverse - according to species, functions, actionMixture of chemicals - Carbons numbers-5 to 20Molecular weight-17 to 880 g/molNo.of double bonds 0 to 13Typical feature-Cis-trans isomerism

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SEX PHEROMONE

LEPIDOPTERA AND

COLEOPTERA

ALARM AND AGGRN

PHEROMONE

APHIDS, BOLL

WEEVIL

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TYPES OF PHEROMONES BASED ON

CHANGES IN INSECT

FUNCTIONAL GROUP

NO. OF COMPOUND

• Primer

• Releaser

• Type-I• Type-II

• Monocomponent

• Multicomponent

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I. BASED ON CHANGES IN INSECT

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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.

A) PRIMER PHEROMONES

(Ekerholm and Hallberg, 2005)

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Produce an immediate change in the behavior of the recipient.

B) RELEASER PHEROMONES

• 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

(Ekerholm and Hallberg, 2005)

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II. BASED ON FUNCTIONAL GROUP

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A. TYPE I PHEROMONE

C12-C18 carbon chain with functional groups -alcohol, aldehyde and acetate

Biosynthesised from de-novo synthesised fattyacid.

Used in approximately 75% of moths

Eg. Lepidopteran moths

(Ando and Yamakawa, 2011)

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B. TYPE II PHEROMONE Comprising unsaturated hydrocarbons and

their epoxy derivates

C17–C23 hydrocarbons and epoxides

orginate from long chain hydrocarbonsproduced outside PGs.

Synthesized in oenocytes or epidermal cells

Geometridae, Arctiidae and cockroach

(Millar et al. 2005).

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III. BASED ON NUMBER OF COMPONENT

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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)

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2. Multicomponent

• Bark Beetle - ipsenol and ipsdienol

• Pink bollworm - Gossyplure

• Cockroach - Blatellaquinone

More than one chemical compound

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2. Multicomponent

• Tobacco cutworm - Spodolure, litlure

• Gram pod borer- Helilure

• Honey bee queen- Queen’s substance

More than one chemical compound

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EXOCRINE GLAND’S ASSOCIATION WITH PHEROMONE PRODUCTION

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Gland associated with pheromone production

• Exocrine glands - Glands that secrete theirproducts (excluding hormones and otherchemical messengers) into ducts (duct glands)which lead directly into the externalenvironment.

• Exocrine glands contain a glandular portionand a duct portion

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TYPES OF EXOCRINE GLANDS

Based on

1. Structure

2. Product secreted

3. Presence of reservoir

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I. Based on structure

1.Simple - duct portion may be unbranched

2. Compound - duct portion may be branched

SIMPLE TUBULAR SIMPLE BRANCHED TUBULAR

SIMPLE ALVEOLAR BRANCHED ALVEOLAR

COMPOUND TUBULAR COMPOUND ALVEOLAR COMPOUND TUBULO ALVEOLAR

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PRODUCTS SECRETED BY EXOCRINE GLANDS

Glands Location Function

Setal glands Scoli Irritant fluid

Stink glands/ Repugnatorialglands

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

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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).

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ANATOMY OF PHEROMONE PRODUCING GLANDS AND

DISCHARGE

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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 transported

through long ducts to the cuticular

surface for release.

Newly discovered pheromone is

nicknamed “parcoblattalactone”

1. BLATTODEA

(Liang and Schal, 1993)

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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 portion of the oviduct.

(Borg Karlson et al . , 1988)

2. COLEOPTERA – CLICK BEETLE

sacciform glands

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Males produce hydrocarbon aggregation pheromone in large

disk-like abdominal oenocytes that occur within the body

cavity.

These cells are connected by tracheae to the integument, with

the pheromone secreted into tracheal-associated ductules

eventually reaching the cuticular surface of the male through

the spiracles.

2. SAP BEETLE - CARPOPHILUS

FREEMANI DOBSON

(Dowd and Bartelt, 1993; Nardi et al., 1996)

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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)

3. RED FLOUR BEETLE

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A glandular organ in the apical (10th and 11th)

antennal segments of the male Batrisodes oculatus

Aube is involved in secreting a female attractant

4. ANT LOVING BEETLE

(de Marzo and Vit , 1983)

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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

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Lepidopteran females produce and release sex pheromone

components from bulbous extrudable glands located between

the 8th and 9 th abdominal segments

(Bjostad et al . , 1987).

4. Lepidoptera 33

Female exposing her pheromone gland, located at the tip of

her abdomen.

Such pheromone-releasing behavior, termed “calling,”

SATURNIID MOTH- Hemileuca electra

pheromone gland

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Spear-marked black moth, Rheumaptera hastata - gland consists

of a pair of internal tubular organs that extend from their common

opening in the 9th abdominal segment anteriorly into the 7th

abdominal segment ( Werner, 1977)

Paired tubular glands have been identified from 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).

EXCEPTIONS

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5. HYMENOPTERA

1. Nasanov gland

2. Koschevnikov gland

3. Dufour’s gland

4. Mandibular glands

HONEY BEE PHEROMONE GLANDS

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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

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BIOSYNTHESIS

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De nova BIOSYNTHESIS OF PHEROMONE

PHEROMONE PRODUCT

ACETYLATION (ACETYL TRANSFERASES) OR OXIDATION

FINAL FUNCTIONAL GROUP MODIFICATION BY REDUCTION (REDUCTASES)

CHAIN SHORTENING BY Β-OXIDATION

DESATURATION (DESATURASES)

FATTY ACID METABOLISM

(Tillman et al., 1999)

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Proposed pathways for lepidopteran

sex pheromones

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PHEROMONE PRODUCTION

Hydro carbon formation

Elongation

Fatty acid synthesis

(Juarez et al., 1992)

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TYPE-II PHEROMONE BIOSYNTHESIS BLATELLA GERMANICA

(Juarez et al. , 1992)

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Dipteran pheromone biosynthesis

Fatty acid synthesis

desaturation elongation

reductive decarboxylation.

Unsaturated hydrocarbons

epoxides

(Wicker and Jallon, 1995; Pennanec’h et al., 1997)

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HOUSE FLY

(Blomquist et al., 1984; Ahmad et al., 1987)

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PHEROMONE PRODUCTION IN

BOMBYX MORI

bombykol

Fatty acyl reduction

desaturation

Fatty acid synthesis

(Ando et al., 1988)

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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

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ENDOCRINE REGULATION OF INSECT PHEROMONE PRODUCTION

• Insects utilize at least three hormonalmessengers to regulate pheromonebiosynthesis

Juvenile hormone III

Fatty acyl–CoA elongation enzyme(s) (elongases)

Pheromone biosynthesis activating neuropeptide (PBAN)

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HORMONAL MESSENGERS

• Blattodean and coleopteran - Juvenile hormoneIII

• Diptera - one or more fatty acyl–CoA elongationenzyme(s) (elongases)

• Lepidopteran - pheromone biosynthesisactivating neuropeptide (PBAN)

(Barth and Lester, 1973)

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PHEROMONE BIOSYNTHESIS ACTIVATING NEUROPEPTIDE (PBAN)

• A polypeptide hormone that controls thesynthesis of the sex pheromone in moths hasbeen named PBAN

• PBAN is produced in the suboesophagealganglion (SOG)

• Transported to the corpora cardiaca (CC) beforeits release into the hemolymph

• PBAN acts directly on pheromone gland cells byusing calcium and cAMP (Cyclic adenosinemonophosphate) as second messengers.

(Barth and Lester, 1973)

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Role of PBAN in moths

• Red banded leafroller (Argyrotaeniavelutinana) - PBAN regulates pheromonebiosynthesis

• Several moths - PBAN appears to regulate anenzyme, a Δ 11 desaturase

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PHEROMONE BLENDING

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PHEROMONE BLENDING

• Survey - Ten lepidopteran species - extracts ofthe ovipositor tips - unusual fatty acids thathad the same carbon lengths, double-bondpositions, and stereochemistries as theacetate, alcohol, or aldehyde pheromonecomponents for the species

(Wolf et al., 1981).

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PHEROMONE BLEND RATIO REGULATION

Ratio-regulated blends of the different pheromone components.

• Pyralid moth - Ostrinia furnacalis uses asex pheromone blend of (E)- and (Z)-12tetradecenyl acetate (E12-and Z12-14:OAc)in a 53:47 ratio

• In the closely related species Ostrinianubilalis, that uses a mixture of (E)- and(Z)-11-tetradecenyl acetate (E11- and Z11-14:OAc) as its pheromone

(Cheng et al., 1981).

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How the blend specificity achieved?

• Compounds having different oxygenated functionalgroups (aldehydes , acetates, alcohols or ketones)

• Compounds having different numbers of carbons inthe skeleton

• Compounds having different degrees of unsaturation

• Compounds having different geometries of doublebonds

• Blends of compounds having different ratios of thesame components

• Blends of compounds containing different numbers ofcomponents

(Wyatt, 2010)

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HOST COMPOUNDS CONVERSION AS PHEROMONE

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Douglas-fir beetle

• Monoterpene limonene from host Douglas-fir.

• Douglas-fir beetle release limonene asrespective aggregation pheromonecomponents.

• Limonene functions as a synergist indouglas-fir beetle.

• Biosynthesis of terpene-derivedpheromones via modification of hostcompounds in the curculionid

• Feeding on host Pinus spp. phloem inducessynthesis of JH III by the corpora allata.

(Rudinsky et al., 1977)

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CONVERSION BY THE MALE ORNATE MOTH Utetheisa ornatrix

Crotalaria spectabilis monocrotaline oxidation

hydroxydanaidalrelease

(Conner et al., 1981, 1990;Eisner and Meinwald, 1995)

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CONVERSION BY FEMALES OF THE SALT MARSH CATERPILLAR MOTH

Host plant

Linolenic acid (Z9,Z12,Z15-

octadecatrienoic acid; Z9,Z12,Z15–18:Ac)

Elongationdecarboxylated

C21 alkatriene C21 epoxide

(Rule and Roelofs, 1989)

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CONVERSION BY THE MALE Ips paraconfusus Lanier

ponderosa pine myrcene

(S)-(+)-ipsdienoland

(S)-(2)-ipsenol

release

(Hendry et al., 1980)

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PHEROMONE RELEASE

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RELEASING OF PHEROMONE

• Releasing into the environment involve twoseparate process:

1. Synthesis

2. Dispersal

• Pheromone producing gland with out reservoir

- directly to dispersal.

• Producing gland with reservoir

- temporally separate.

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PHEROMONE DISPERSAL

• Androconial organs : Presenton male butterflies and mothwhich ending in a brush-likerow process.

• Male moths extentandroconia to releasepheromones

(Jason et al., 2003)

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PHEROMONE DISPERSAL

• The hairy appendages are theeverted coremata

e.g Creatonotos gangis

• Ants drags the tip of theabdomen over the surface asit runs.

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• Insect curls its body, so thestored phermone which is incontact with cuticle willdisperse. E.g. ant (Pachycondylatarsata).

• In bumblebee, labial glandpheromones are transferred tothe vegetation by biting.

• In honey bee colony pheromonedispersal facilitate by fannerbees

PHEROMONE DISPERSAL64

• Releasing the sex attractantpheromone-calling.

• Pheromone gland exposed tooutside by

-depressing the tip of the abdomen

-extension of the abdomen

-gland is inverted by haemolymphpressure

• Exposure of the gland isaccompanied by wing vibrationwhich facilitate dispersal.

PHEROMONE DISPERSAL65

CHEMORECEPTORS

• Insects can sense various chemicalsubstances in their environment.

• Gaseous form they may be detected asodors.

• Solid or liquid form they are perceived astastes by gustatory receptors

• Sense of taste (contact chemoreception)

• Sense of Smell (remote chemoreception)

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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

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OLFACTORY SYSTEM

Olfactory systems detect and differentiateodor stimuli

Olfactory receptor neurons encodeinformation about odors

Insect ORNs are distributed in sensilla,usually in the form of sensory hairs

Odorants pass through tiny pores in thewalls of these sensilla and stimulatedendrites bathing in the lymph inside

(Silbering and Benton, 2010)

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PERCEPTION AND SIGNAL PROCESSING

Carry them to specialized receptors on the surface of dendrites in the sensillum.

Bound to pheromone binding proteins that solublize the pheromone in the aqueous receptor lymph

Odorant molecules diffuse into the lumen of the sensilla

Peripheral perception at the antenna where specialized sensilla

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Pheromone molecules must be degraded rapidly.

Electrochemical signal transduction

Inositol triphosphate-gated Ca++ channels in the dendritic membrane

G-protein-mediated activation of phospholipase C and generation of inositol triphosphate

(Laissue and Vosshall, 2008)

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Mechanism of perception73

PHEROMONE BINDING PROTEINS

• PBPs - small , globular, water-soluble proteins

• Highly concentrated in the aqueous sensillar lymph

• PBPs are broadly expressed in most olfactoryorgans

• PBP binds pheromone with certain selectivity

• Initiating the first biochemical step in odorantreception (Leal, 2013).

• Transporting hydrophobic sex pheromone acrossaqueous sensillar lymph to the surface of olfactoryreceptor neurons

(Buck and Axel, 1991; Benton et al., 2006)

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BEHAVIORAL RESPONSE TO PHEROMONE

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• Orientation of male moths towards thefemale-emitted sex pheromone in a naturalenvironment.

• Pheromone perception triggers a sustainedupwind flight in male moths (positiveanemotaxis).

• Fluttering in silk worm

• Wing raising behavior in Blattodea germanica

• Increased locomotion in trail-following ants

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Periplaneta americana

Grooming of antenna in male

Move upwind

Increased locomotor activity

Honey bee (Queen MandibularPheromone)

Retinue

Swarming

Mating flight

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FACTORS AFFECTING THE PHEROMONE PRODUCTION

Temperature Photoperiod

Host plants Age and mating

PHEROMONE PRODUCTION

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CONCLUSION

• Insects have well defined communication systemwhich rely more on chemical communication in theform of pheromones for mate finding and aggregation

• Insects synthesis their own pheromone from the byeproducts of metabolic activity especially from fattyacid metabolism and these reactions are catalyzed bythe enzymes.

• The success rely on the reception by its conspecifics

• These properties of pheromone can be exploited forattracting the crop pest by formulating and used forbetter crop protection

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