My laboratory is engaged in research on several aspects in the chemical ecology of social insects.

Chemical behavioral and neurochemical bases of nestmate recognition
Nestmate recognition, a mechanism that evolved in social insects as defense against exploitation of nest resources, is largely mediated by chemical signals. When two individuals meet they match the label, the chemical signal it carries on the epicuticle and represents the colony odor, with a neural template present in the brain. If the label matches the template amicable interactions between the individual ensue, otherwise they engage in aggressive interaction.
In my laboratory we investigate the chemical nature of recognition signals in ants and the mode by which the genetically based individual odors blend into a uniform colony odor. Through chemical extraction and identification and behavioral assays we demonstrated that cuticular hydrocarbons comprise at least part of the label in several ant species. Using radioactive tracers we further demonstrated that individual ants share their label with other nest members, thus achieving a uniform colony odor and is distinguished from that of other homospecific colonies. The rate and magnitude of transfer depend on the modality used; Trophallaxis is by far the most efficient mode of transfer followed by allogrooming and to a minor extent other body-to-body contacts. In all of these case we discovered that the postpharyngeal gland, a head exocrine gland that is idiosyncratic to ants, act as a “gestalt organ” where individual admix their proper hydrocarbon pool with that they acquire from their nestmate.
The queen is a prime motivator for worker aggression and territoriality. Under queenless conditions worker become gradually less aggressive to the point where two alien colonies can merge to a single colony. It is assumed that the queen emits a primer pheromone that affects the discrimination threshold of workers and renders them intolerant to even slight deviation in recognition pheromone composition. These social interactions are apparently mediated by octopamine. Social isolation seems to create a deficiency in this biogenic amine and augment the intensity of social activity including trophallaxis. By treating the ants with either octopamine or an octopamine-antagonist we can modulate this effect.
In the future we aim at understanding the mode of action of octopamine and other biogenic amine on social cohesion on the one hand and aggressive behavior on the other hand.

Caste specific pheromones and queen-worker conflict in the honeybee.
Social insects are endowed with pheromones that regulate a multitude of social behaviors, many of which exhibit caste specific chemistry. Queens of the honeybee Apis mellifera, for example, possess multiple exocrine glands that produce complex caste specific pheromones. Among these the best researched are the mandibular and Dufour’s gland. Caste specificity however is not due to “fixed caste specific biosynthetic pathways”, but rather show plasticity in workers according to their physiological and social state. Queenless workers that have developed ovaries exhibit the typical queen secretion, both in the mandibular and Dufour’s glands. Thus, the queen, probably via a queen signal, regulates the glandular expression of workers. A series of biosynthesis studies with Dufour’s gland have shown that when incubated in vivo, glandular expression match the social of the worker investigated. Glands of queenright workers show only newly synthesized hydrocarbons (typical worker compounds), whereas glands of queenless workers produce also de-novo esters (typical queen compounds). In contrast, glands incubated in vitro produced the queen-like esters irrespective of the social status of the workers utilized.
The close association between ovarian development and the occurrence of queen-like pheromones suggest that these provide a reliable fertility signal. Producing a chemical signal by the queen denoting her fertility is a rapid way to transmit the information. Since it is coupled with egg laying it become immune to cheating. Producing the signal by workers under queenless hopeless situation may give then an edge in worker-worker competition over reproduction and help recruiting helper nestmates.
In the future we wish to unravel the queen signal that is responsible for the regulation of mandibular and Dufour’s gland expression in workers, and elucidate by which mechanism the queen compounds production in is turned on and off. We also aim at understanding better the role of the gland in queen-worker social interactions, in particular regarding queen-worker and worker-worker conflicts over reproduction.

Queen-worker conflict over male production in bumblebees
Bumblebees provide an excellent model for studying queen-worker conflict over reproduction. The constitute monogyne colony in which the queen is singly inseminated. Kin selection therefore predicts that worker will gain more fitness by rearing either sons or nephews (worker derived males) than brothers (queen derived males). Since this species construct annual colonies there is a narrow window for worker reproduction and thus overt conflict is predicted to occur towards the end of colony cycle.
The conflict over male production in Bombus terrestris is characterized by workers oviposition on the one hand and mutual oophagy on the other hand. This so-called competition phase is also tightly correlated with new queen production and marks the end of the colony life cycle. Despite the great reproductive efforts made by workers, molecular data indicate that the overwhelming majority of the males are queen-derived. However, in many cases queen death occurs during the competition phase, leaving the stage open for worker reproduction. It is hypothesized that queen death is cause by matricide that has evolved as a countermeasure for queen dominance in reproduction.
Our research in the near future centers on deciphering the mechanisms underlying this behavioral arms race. We wish to elucidate the signals that trigger the competition phase and how this is related both to worker reproduction and gyne formation.
Contrasting bumblebee and honeybee queen-worker interactions paves the way to a better understanding of the evolution of sociality in terms of genetic gain vs. genetic conflict.

Ants

Soroker, V., Vienne, C. Hefetz, A ., and Nowbahari, E. 1994 The P ostpharyngeal Gland as a “Gestalt” Organ for Nestmate Recognition in the Ant Cataglyphis niger . Naturwissen. 81:510-513

Soroker, V., Vienne, C. and Hefetz, A . 1995 Hydrocarbon dynamics within and between nestmates in Cataglyphis niger (hymenoptera: formicidae). J. Chem. Ecol. 21:365-378

Vienne, C., Soroker, V. and Hefetz, A . 1995 Congruency of hydrocarbon patterns in heterospecific groups of ants: transfer and/or biosynthesis ? Insectes Sociaux 42:267-277

Errard C., and Hefetz, A . (1997) Label familiarity and discriminatory ability of ants reared in mixed groups. Insectes Sociaux   44: 1-10.

Lahav, S., Soroker, V., Vander Meer,   R. K., and Hefetz, A . (1998) Nestmate recognition in the ant Cataglyphis niger : Do queens matter? Behav. Ecol. Sociobiol. 43: 203-212

Lahav, S., Soroker, V., Vander Meer R. K., and Hefetz, A . (1999) Direct Behavioral Evidence for Hydrocarbons as Ant Recognition Discriminators. Naturwissen. 86:246-249

Soroker, V., and Hefetz, A . (2000) Hydrocarbon site of synthesis and circulation in the desert ant Cataglyphis niger J. Insect Physiol. 46: 1097-1102

Boulay, R., Hefetz, A ., Soroker, V., and Lenoir, A . (2000) Camponotus fellah colony integration: worker individuality necessitates frequent hydrocarbon exchanges. Anim. Behav. 59:1127-1133

Boulay, R., Soroker, V., Godzi n ska, E. J., Hefetz, A . and Lenoir, A. (2000) Octopamine reverses the isolation-induced increase in trophallaxis in the Carpenter ant Camponotus fellah J. Exp. Biol. 203: 513-520

Lenoir, A., Hefetz, A , Simon,T, and Soroker, V. 2001 Comparative study of the dynamics of gestalt odour formation in two ant species, Camponotus fellah and Aphaenogaster senilis (Hymenoptera: Formicidae). Physiol. Entomol. 26:275-283

Lenoir, A., D'Ettorre, P., Errard C., & Hefetz, A . 2001 Chemical ecology and social parasitism in ants. Ann. Rev. Entomol 46: 573-599.

Boulay R., Katzav-Gozansky, T., Vander Meer, R.K. and Hefetz, A., 2003 Colony insularity through queen control on worker social motivation in ants. Proc. Royal Soc Lond. B 270:971-977

Lavine, B.K, Davidson, C., Vander Meer, R.K., Lahav, S., Soroker, V., and Hefetz, A. 2003 Genetic Algorithms for Deciphering the Complex Chemosensory Code of Social Insects Chemom. Intell. Lab. Syst. 66:51-62

Katzav-Gozansky, T., Boulay, R., Vander Meer, R.K., and Hefetz, A. 2004 In-Nest environment modulates nestmate recognition in the ant Camponotus fellah. Naturwissenschaften 91:186-190

Boulay R., Katzav-Gozansky T., Hefetz, A. and Lenoir, L. 2004 Odour convergence and tolerance between nestmates through trophallaxis and grooming in the ant Camponotus fellah (Dalla Torre). Insectes Sociaux 51:55-61

Richard F-J, Hefetz, A., Christides J-P, and Errard, C. 2004 Food influence on colonial recognition and chemical signature between nestmates in the fungus growing ant Acromyrmex subterraneus subterraneus. Chemoecology 14:9-16

Errard, C., Delabie, J., Jourdan, H., and Hefetz, A. 2005 Intercontinental chemical variation in the invasive ant Wasmannia auropunctata (Roger) (Hymenoptera Formicidae): a key to the invasive success of a tramp species. Naturwissenschaften 92:319-323

Ruano, F., Hefetz, A., Lenoir, A., Francke, W., and Tinaut, A. 2005 Dufour’s gland secretion as repellent used during usurpation in the slave-maker ant Rossomyrmex minuchae. J. of Insect Physiol. 51:1158-1164

Errard, C., Hefetz, A., and Jaisson, P. 2006 Social discrimination tuning and chemical sameness in ants Behav. Ecol. Sociobiol. 59:353-363

Cruz-López, L., Jackson, B.D., Hefetz, A., and Morgan, E.D. 2006 Tobacco alkaloids in the venom of Messor ants. Biochem. syst. Ecol. 34:199-204

Errard, C., Ruano, F., Richard, F-J, Lenoir, A., Tinaut, A., and Hefetz, A. 2006 Co-evolution-driven cuticular hydrocarbon variation between the slave-making ant Rossomyrmex minuchae and its host Proformica longiseta (Hymenoptera: Formicidae). Chemoecology 16: 235–240

Richard, F.-J., Poulsen, M., Hefetz A., Errard, C., and Boomsma J. J. 2007 The origin of chemical profiles of fungal symbionts and their significance for nest-mate recognition in Acromyrmex leaf-cutting ants. Behav. Ecol. Sociobiol. 61:1637–1649

Boulay R., Hefetz, A., Cerdá X., Devers, S., Francke, W., Twele, R., and Lenoir, A., 2007 Production of sexual in a fission-performing ant: dual effects of queen pheromones and colony size. Behav Ecol. Sociobiol. 61:1531–1541

Boulay R., Cerda X., Roldan M., Simon T., and Hefetz A. 2007 Intraspecific competition in the ant Camponotus cruentatus: should we expect the “dear enemy” effect? Anim. Behav. 74: 985-993

Hefetz, A. 2007 The evolution of hydrocarbon pheromone parsimony in ants (Hymenoptera: Formicidae) –interplay of colony odor uniformity and odor idiosyncrasy – a review. Myrmecol. News 10: 59-68

Le Conte, Y. and Hefetz, A. 2008 Primer pheromones in social Hymenoptera. Annu. Rev. Entomol. 53:523-542

Bumble bees

Hefetz, A . (1998) Exocrine glands and their products in non- apis bees: chemical, functional and evolutionary perspectives. In Pheromone communication in social insects: Ants, wasps, bees, and termites. Vander Meer, R.K., Breed, M., Winston, M., and Espelie, C. (eds) pp 236-256

Bloch, G., Borst, D.W., Huang, Z.-Y., Robinson, G.E. and Hefetz, A . 1996 Effects of social conditions on JH-mediated reproductive development in Bombus terrestris workers.   Physiol. Ent. 21: 257-267

Cnaani, J., Borst, D., Huang, Z.-Y., Robinson, G., and Hefetz, A . 1997 Differences in development and rates of JH biosynthesis between queen and worker larvae in Bombus terrestris . J. Insect Physiol. 43: 373-381

Bloch, G. and Hefetz, A . (1999) Regulation of Reproduction by Dominant Workers in Bumble Bee ( Bombus terrestris ) Queenright Colonies. Behav. Ecol. Sociobiol. 45: 125-135

Bloch, G. and Hefetz, A . (1999) A reevaluation of the role of the mandibular glands in the regulation of reproduction in bumblebee colonies J. Chem. Ecol. 25: 881-896

Bloch, G., Borst, D. W., Huang. Z-Y., Robinson, G. E., Cnaani, J., and Hefetz, A . (2000) JH Titers, JH Biosynthesis, Ovarian Development and Social Environment in Bombus terrestris J. Insect Physiol. 46:47-57

Bloch, G., Hefetz , A . and Hartfelder, K.(2000) Ecdysteroid titer, ovary status, and dominance in adult worker and queen bumble bees ( Bombus terrestris ) J. Insect Physiol 46:1033:1040.

Bloch, G., Simon, T., Robinson, G.E. and Hefetz, A . (2000) Brain Biogenic Amines and Reproductive Dominance in Bumble Bees ( Bombus terrestris) J Comp. Physiol. A 186:261-268

Cnaani, J., Robinson G.E., Bloch G., Borst, D., and Hefetz, A . (2000) The effect of queen-worker conflict on caste determination in the bumble bee Bombus terrestris   Behav. Ecol. Sociobiol. 47:346-352

Hartfelder, K., Cnaani, J., and Hefetz, A . (2000) Caste-specific differences in ecdysteroid titers in early larval stages of the bumble bee Bombus terrestris : Endocrine evidence that caste determination and caste differentiation are distinct processes J. Insect Physiol. 46: 1433-1439

Cnaani, J. Robinson G.E, and Hefetz, A . 2001 The critical period for caste determination in Bombus terrestris and its juvenile hormone correlates. J. Comp. Physiol. 186:1089-1094

Cnaani, J., and Hefetz, A . (2001) Are queen Bombus terrestris giant workers or are workers dwarf queens? Solving the “chicken and egg” problem in a bumblebee species. Naturwissen. 88: 82-84

Alaux C., Jaisson P. and Hefetz A. 2004 Queen influence on worker reproduction in Bombus terrestris colonies (Hymenoptera, Apidae, Bombinae) Insectes Soc. 51:287-293

Alaux C., Savarit F., Jaisson P. and Hefetz A. 2004 Does the queen win it all? Queen-worker conflict over male production in Bombus terrestris Naturwissenschaften 91:400-403

Alaux C., Jaisson P. and Hefetz A. 2005 Reproductive decision in semelparous social insects: a pace-maker queen in bumblebees colonies Behav. Ecol. Sociobiol. 59:270-277

Alaux, C., Jaisson, P., and Hefetz, A. 2006 Regulation of worker reproduction in bumblebees: workers eavesdrop on a queen signal Behav. Ecol. Sociobiol. 60:439-446

Alaux, C., Hefetz, A., and Jaisson, P. 2006 Plasticity of worker reproductive strategies in Bombus terrestris: lessons from artificial mixed-species colonies Anim. Behav. 72:1417-1425

Alaux, C, Boutot, M., Jaisson P, and Hefetz, A. 2007 Reproductive plasticity in Bombus terrestris workers – reversion from fertility to sterility under queen influence. Behav Ecol. Sociobiol. 62:213-222

Honeybees

Katzav-Gozansky T., Soroker V., Cojocaru M., Erdmann D. H., Francke W., and Hefetz, A . (1997) Plasticity of caste specific Dufour’s gland secretion in the honey bee ( apis mellifera l.) Naturwissen. 84:238-241

Katzav-Gozansky, T. Soroker, V. and Hefetz, A . Plasticity in caste-related exocrine secretion biosynthesis in the honey bee ( Apis mellifea ). (2000) J. Insect Physiol. 46:993-998

Katzav-Gozansky, T., Soroker, V., Ionescu, A., Robinson, G. E., and Hefetz, A ., (2001) Task related chemical analysis of worker honeybees’ labial gland secretion. J. Chem. Ecol. 27:919-926

Katzav-Gozansky, T., Soroker, V., Ibarra, F., Francke, W., and Hefetz, A. 2001 Dufour’s gland secretion of the queen honey bee: an egg discriminator pheromone or a queen signal? Behav. Ecol. Sociobiol. 51:76-86

Katzav-Gozansky, T., Hefetz A., and Soroker, V. 2002 Evolution of worker sterility in honey bees: Egg-laying workers express queen-like secretion in Dufour’s gland. Behav. Ecol. Sociobiol. Forum 51:588-589

Katzav-Gozansky, T. Soroker, V. and Hefetz, A. 2002 Honeybees Dufour's gland - idiosyncrasy of a new queen signal. Apidologie 33:525-537

Katzav-Gozansky, T., Soroker, V., Ibarra, F., Francke, W., and Hefetz, A. 2001 Dufour’s gland secretion of the queen honey bee: an egg discriminator pheromone or a queen signal? Behav. Ecol. Sociobiol. 51:76-86

Katzav-Gozansky, T., Hefetz A., and Soroker, V. 2002 Evolution of worker sterility in honey bees: Egg-laying workers express queen-like secretion in Dufour’s gland. Behav. Ecol. Sociobiol. Forum 51:588-589

Katzav-Gozansky, T. Soroker, V. and Hefetz, A. 2002 Honeybees Dufour's gland - idiosyncrasy of a new queen signal. Apidologie 33:525-537

Sole, C.L., Kryger, P., Hefetz, A., Katzav-Gozansky, T., and Crewe , R.M. 2002 Mimicry of queen Dufour’s gland secretions by honey bee workers of Apis mellifera scutellata and A. m. capensis . Naturwissen. 89:561-564

Katzav-Gozansky, T., Soroker, V. and Hefetz, A. 2003 Honeybee egg-laying workers mimic a queen signal. Insect Soc. 50:20-23

Katzav-Gozansky, T., Soroker, V., Kamer, J., Schulz, C., Francke, W., and Hefetz A. 2003 Ultrastructural and chemical characterization of egg surface of honeybee worker and queen-laid eggs. Chemoecology 13: 129-134

Katzav-Gozansky, T., Boulay, R., Soroker, V., and Hefetz, A., 2004 Queen-signal modulation of worker pheromonal composition in honeybees Proc. Royal Soc Lond. B 271:2065-2069

Dor, R., Katzav-Gozansky, T., and Hefetz, A. 2005 Dufour's gland pheromone as a reliable fertility signal among honeybee (Apis mellifera) workers. Behav. Ecol. Sociobiol. 58:270-276

Katzav-Gozansky T., Boulay R., Soroker V., and Hefetz A. 2006 Queen-signal modulation of worker pheromonal composition in honeybees J. Comp. Physiol. 192:737-742

Malka, O., Shnior, S., Hefetz, A., and Katzav-Gozanski, T. 2007 Reversible royalty in worker honeybees under the queen influence. Behav Ecol Sociobiol. 61:465–473

Katzav-Gozansky, T., Hefetz, A., and Soroker V. 2007 Brain modulation of Dufour's gland ester biosynthesis in vitro in the honeybee ( Apis mellifera ) Naturwissenschaften 94:407–411

Inbar, S. and Hefetz, A. 2008 Kin composition effects on the reproductive competition among queenless honeybee workers. Naturwissenschaften (DOI 10.1007/s00114-008-0343-6 )

Malka O., Snior, S, Katzav-Gozansky, T, and Hefetz, A. 2008 Aggressive reproductive-competition among hopelessly queenless honeybee workers triggered by pheromone signaling Naturwissenschaften ( 10.1007/s00114-008-0358-z )

Research associate

Dr. Tamar Katzav-Gozansky
Tovit Simon

Current Students:

Phd

2003 -  Osnat Malka, Social and Physiological Regulation of Cast Specific of Mandibular Gland Secretion of the Honey Bee (Apis mellifera).

2008 - Etya Amsalem

2008 - Merav Vonshak

M.Sc.

2003 - Shiri Shnieor, Reproductive dominance in the Honeybee Apis mellifera - chemical and behavioral aspects.

2003 - Rina Milman, Diet effect on nestmate recognition behavior in the ant Camponatus fellah.

2008 - Itai lalzar

2008 - Galia Wolpe