OLFACTORY COMMUNICATION IN MAMMALS

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OLFACTORY COMMUNICATION IN MAMMALS

• Mammalogy
• EEOB 625
• 9 February 2004

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• Olfactory Communication In Vertebrates
• Pheromone is a chemical released by one
• individual that elicits a response in one
• or more individuals of the same species
• Common in vertebrates except birds
• Source of chemical in the sender
• Chemosensory tissues in the receiver
• Criterion for pheromone status for a
• chemical? Effective in the absence of all
  other
• stimuli from the source
  individual
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Sites of Pheromone Production

• Skin Glands sternal, ano-genital, hip, foot,
• pre-orbital, tarsal, mandibular, chest
• Saliva and secretions of the oral angle gland
• Urine feces (with preputial anal glands)
• Examples Castor canadensis - castor anal
  glands and the anal glands of mustelids
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The mammalian skin A major source of pheromones

• Epidermis the pheromonally functional part of
• skin (dermis the
  structural part)
• Derivatives of the epidermis
• Hair - guard hairs underfur, vibrissae,
• follicles, piloerector muscles, and
  nerves
• Skin glands
•  1. Sebaceous glands oil glands of hair
  follicles
• 2. Eccrine - sweat glands
• 3. Apocrine - odor producing glands

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Epidermis
Dermis
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Sebaceous
Ecrine
Apocrine
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Chemoreception and the response to pheromones

• Olfactory epithelium of nasal turbinates the
  main olfactory system perception of odor
• External Nares perception of direction
• Factors in sensitivity to odors pheromones
• Vomeronasal organ (Jacobson's Organ)
• Sensitive to both volatile and non-volative
  chemeicals
• Important in detection of sex pheromones
• Flehmen behavior in ungulates

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Typical Mammal Human
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(VNO)
Vascular sinus
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Properties Types of Pheromones

• Chemical Properties volatile non-volatile
  compounds
• e.g., amines, carboxylic acids, fatty
  acids (important?)
• Signaling pheromone Definition examples
• Broadcast scent marking - "territorial"
  individual and
• Family recognition
• Sexual attractants estrous females
• Priming pheromone definition examples
• Reproductive activation puberty estrous
  cycles
• Response to pheromones hypothalamus,
  pituitary, ?
• Reproductive activation in the gray short-tailed
  opossum

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Pheromonal Activation of Reproduction in Female
Opossums
Females in estrus
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Supra-sternal gland of male opossum
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Phermomonal Induction of Puberty in Opossums

• Pheromonal Exposure (from 90 days)
• Direct Indirect Isolated
• N 22 22 12
• Estrus 22 13 0
• Days at Estrus 127 162 (none at 180)
• Weight (g) 61 59 (61,
  nonestrus) at 1st Estrus

Stonerook Harder (1992)
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Ovarian follicle diameter
Juvenile body weight