BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Neurochemical mechanisms of phenotypic plasticity underlying swarm
  formation in the Desert Locust - Dr Swidbert R. Ott and Dr Stephen M. Rog
 ers\, Department of Zoology
DTSTART:20080418T100000Z
DTEND:20080418T103000Z
UID:TALK11696@talks.cam.ac.uk
CONTACT:Hannah Critchlow
DESCRIPTION:The existence of alternative phenotypes arising from a single 
 genotype that are expressed according to environmental conditions is of co
 nsiderable evolutionary significance\, but the controlling mechanisms rema
 in elusive. One major source of environmental variability is the presence 
 and actions of conspecifics which in some species has driven the evolution
  of multiple phenotypes to adapt to changing population densities. Desert 
 locusts\, Schistocerca gregaria\, display a striking example of just such 
 a density-dependent phenotypic plasticity\, changing reversibly between a 
 little seen solitarious phase and the notorious swarming gregarious phase.
  The two phases differ extensively in morphology and physiology\, but beha
 viour is the key to both establishing and maintaining phase. Solitarious l
 ocusts actively avoid other locusts whilst gregarious locusts form cohesiv
 e groups\, but forced crowding of solitarious locusts for just a few hours
  leads to a rapid reorientation towards gregarious behaviour. How this rap
 id behavioural transition is mediated\, however is unknown. We show that s
 erotonin\, an evolutionarily conserved mediator of neuronal plasticity\, p
 erforms this function. Serotonin in the CNS is correlated with the degree 
 of gregarious behaviour\; preventing endogenous serotonin synthesis or blo
 cking its action prevents behavioural gregarization and application of ser
 otonin or receptor agonists drives its acquisition. Our findings suggest t
 hat serotonin is both necessary for gregarization to occur and sufficient 
 to induce it. The initial switch to gregarious behaviour is an essential p
 ivot point\; once solitarious locusts have overcome their mutual aversion 
 sensory positive feedback drives the acquisition of further gregarious pha
 se characteristics and possible swarm formation. This study identifies a n
 eurochemical mechanism for the initiation of swarming and demonstrates how
  density-dependent sensory cues can initiate phenotypic change. \n\n
LOCATION:Physiology Lecture Theatre
END:VEVENT
END:VCALENDAR