PRESENTED BY:-IKRIMA NAAZ

BSC.ZOOLOGY(H)2310

CHEMICAL COMMUNICATION IN

HONEY BEES

INDEX

What are pheromones??? Types of pheromones Queen pheromones Worker pheromones Drones pheromones Brood pheromones

PHEROMONES Pheromones are chemical substances

secreted by an animal’s exocrine glands that elicit a behavioral or physiological response by another animal of the same species.

The term was coined by:KARLSON AND LUSCHER IN 1959

A GREEK WORD-PHERO- “To transport” HORMONE-”Stimulate”

CHARACTERISTICS Conspecific-influence the sexual behaviour Effects are expressed via pheromone

receptors Volatile and specific Chemically diverse-according to species

and functions and actions. No.of carbons-5-20 Molecular weight-17-880g/mol Cis and trans isomerism

Honey bee pheromonal glands….. Mandibular gland Nasonov gland Koschevnikov gland Dufour’s gland

TYPES OF PHEROMONES

PRIMER PHEROMONE RELEASER PHEROMONE

Trigger off a chain of physiological changes in the recipient without any immediate effect in the behavior.

Act through gustratory sensilla

Caste determination and reproduction in social insects.

(A) PRIMER PHEROMONE

(b)RELEASER PHEROMONE

Produce immediate effect change in the behavior of the reciepent.

1. Sex pheromones2. Aggregation pheromones3. Anti-aggregation pheromones4. Alarm pheromones5. Egg-laying pheromones6. Brood-tending pheromones7. Recruitment pheromones8. Trail-following pheromones9. Territory marking pheromones and many others

QUEEN PHEROMONES The honey bee queen represents the main regulating

factor of the colony functions. This regulation is largely achieved by means of pheromones, which are produced by different glands and emitted as a complex chemical blend, known as the “queen signal.”

EFFECTS:- worker cohesion, suppression of queen rearing, inhibition of worker reproduction stimulation of worker activities: cleaning, building,

guarding, foraging, and brood feeding. It is known that when the queen is old or sick (low

pheromonal signal) or it dies (no pheromonal signal), workers are driven to rear new queens from young brood within 12–24 hours.

Main Component of the Queen Signal: The Queen Mandibular Pheromone The queen mandibular pheromone (QMP)

is by far the most studied and well-known chemical signal in the honey bee society

Chemically it is very diverse with at least 17 major components; 5 of these compounds are:

9-oxo-2- decenoic acid (9ODA) + cis & trans 9 hydroxydec-2-enoic acid (9HDA) + methyl-p-hydroxybenzoate (HOB) and 4-hydroxy-3-methoxyphenylethanol (HVA).

Beyond the QMP: Other Queen Pheromones

QMP Assistants: Tergal Gland Pheromones Tergal glands, also known as Renner and

Bumann glands. Queen mandibular gland secretions were more

effective than tergal gland secretions in formation of the retinue, but the two secretions together were even more efficient, indicating a releaser function of queen tergal gland pheromone in evoking the worker retinue behavior.

Footprint Pheromone: Tarsal Gland Pheromones

these secretions are oily, colorless substances that are extruded through openings when the bee is walking, from which comes the name footprint pheromones. tarsal gland secretions deposited by the mated queen on the comb inhibit queen cup construction by workers

Fertility Signal: Dufour’s Gland Pheromones

functions for its secretions, linked mainly to reproduction and egg-laying in queens (production of an egg coating or egg marking) and to defense in workers (production of a sting lubricant, neutralization of the remains of the acid secretion in the sting

Aging of the Queen Signal: Koschevnikov Gland Pheromones

honey bee workers the gland produces an alarm pheromone that is released when a bee stings and in queen it has different role to play(balling behaviour).The gland starts degenerating after the queen is 1 year of age and this contributes to the loss of signal in old queens

Regulation of Worker Reproduction: The Mandibular Gland Pheromones

While the queen mandibular glands produce mainly 9-ODA, 9-HDA, HOB, and HVA, in worker mandibular glands the prevailing components are 10-hydroxy-2(E)decenoic acid (10-HDA), 10-hydroxydecanoic acid (10-HDAA), and their respective diacids. worker mandibular glands are able to produce a set of chemicals very similar to those of queen glands and with a comparable action.

Regulation of Worker Activity: Ethyl Oleate The chemical substance that acts as an inhibiting factor delaying

onset of foraging age was identified by Leoncini et al. (2004) as ethyl oleate. This substance was found in high concentrations on the body of adult forager bees.

WORKER PHEROMONES

Nasonov Gland

The gland consists of a mass of cells located beneath the intersegmental membrane, between the sixth and seventh tergites .The glandular secrete is released under the posterior part of the sixth tergite and the workers free it by flexing the tip of the abdomen downward; during the secretion the bee usually stands with the abdomen elevated and fans its wings to facilitate volatile dispersion . Thus it is very easy to recognize workers bees while they are secreting the Nasonov pheromone

Nasanov gland occurs only in workers, not in queens or drones.The Nasonov gland secretion contains:(Z)-citral(E)-ditralnerolgeraniolnerolic acidgeranic acid(E,E)-farnesolEach of the components separately is not as effective as the mixture .Composition of the secretion changes with age of workers and differs between winter and spring

Workers secrete and disperse the Nasonov pheromone by fanning at the hive entrance to orientate other members of the colony toward the nest. It is also released by young workers during their first orientation flights. The pheromone release is especially evident after colony disturbance and can be elicited by nest odors such as comb, honey, pollen, propolis, and QMP

ALARM PHEROMONES- DEFENSIVE BEHAVIOUR

Defensive behavior is the first out-nest task performed by workers and is thus initiated at a younger age than foraging.

There are two different kinds of workers involved in the defensive behavior:

Guard bees are workers that patrol the entrance of the hive in search of bees, insects, animals, or any other object or creature that approaches the colony . They also inspect all bees that land at the hive entrance through antennation to recognize nestmates and reject non-nestmate.

Defenders, also called stingers, are bees that respond to a danger or a disturbance by flying out, stinging, and sometimes pursuing intruders (Breed et al. 1990).

HONEY BEES have two different alarm pheromones, one from each end of the body. The mandibular glands of workers produce:-• 2-heptanone • isopentyl acetate (sting pheromone) The chemical released when a bee stings, isopentyl acetate, is absent in newly emerged workers whereas bees 15+ days of age have one to five mg. There are several other components of the gland such as acetates and alcohols and they may work in conjunction with isopentyl acetate. Actual stinging or defensive behavior is correlated with isopentyl acetate. Smoke in some way masks the pheromone. The second alarm pheromone, 2-heptanone, is produced in worker mandibular glands. It, like isopentyl acetate, is absent in newly emerged workers but is present by foraging age. Bees respond to 2-heptanone at the nest entrance similarly as they do to isopentyl acetate, but it is not nearly as effective in producing a response, requiring 20 to 70 times as much compound before bees respond. Queen and drones lack 2-heptanone.

Drone Pheromones

Lensky et al. (1985)verified the role of drone mandibular gland secretions in attracting other flying drones to congregation areas. Drone mandibular glands are much smaller than those of queens and workers and their size varies according to age. The secretory activity increases from 0–3 days old to a maximum at 7 days of age, while after 9 days the glands were no longer active.

The drone tarsal gland secretion also differs chemically from the female’s, and its biological effects are still obscure .

Drone Acceptance in the Colony Similarly to workers, honey bee drones show

features that determine their acceptance or refusal in the colony. This depends on whether they belong to the colony or not and on their age. According to Free (1957), in late summer young drones of 7 days of age are fed and cleaned by workers, while older, sexually mature drones (average age 23 days) are rejected and attacked. The mechanism that might be used by the workers to distinguish between drones of different ages could be the perception of chemical signals on the drone surface.

BP components act as primer pheromones regulating, in synergy with QMP, worker ovarian development. In particular, ethyl palmitate and methyl linolenate were found to act as worker ovary development inhibitors

BROOD PHEROMONE