title: Participation of irradiated Anopheles arabiensis males in swarms following field release in Sudan.
abstract: BACKGROUND
  The success of the sterile insect technique (SIT) depends the release of large numbers of sterile males, which are able to compete for mates with the wild male population within the target area. Unfortunately, the processes of colonisation, mass production and irradiation may reduce the competitiveness of sterile males through genetic selection, loss of natural traits and somatic damage. In this context, the capacity of released sterile Anopheles arabiensis males to survive, disperse and participate in swarms at occurring at varying distances from the release site was studied using mark-release-recapture (MRR) techniques.
  
  
  METHODS
  In order to assess their participation in swarms, irradiated and marked laboratory-reared male mosquitoes were released 50, 100 or 200 m from the known site of a large swarm on three consecutive nights. Males were collected from this large swarm on subsequent nights. Over the three days a total of 8,100 males were released. Mean distance travelled (MDT), daily probability of survival and estimated population size were calculated from the recapture data. An effect of male age at the time of release on these parameters was observed.
  
  
  RESULTS
  Five per cent of the males released over three days were recaptured. In two-, three- and four-day-old males, MDT was 118, 178 and 170 m, and the daily survival probability 0.95, 0.90 and 0.75, respectively. From the recapture data on the first day following each release, the Lincoln index gives an estimation of 32,546 males in the natural population.
  
  
  CONCLUSIONS
  Sterile An. arabiensis males released into the field were able to find and participate in existing swarms, and possibly even initiate swarms. The survival probability decreased with the age of male on release but the swarm participation and the distance travelled by older males seemed higher than for younger males. The inclusion of a pre-release period may thus be beneficial to male competitiveness and increase the attractiveness of adult sexing techniques, such as blood spiking.
authors.forename: Tellal B
authors.initials: TB
authors.lastname: Ageep
authors.affiliation: Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency, Wagramerstraße 5, PO Box 100A-1400 Vienna, Austria. damiensdavid@hotmail.com.
authors.forename: David
authors.initials: D
authors.lastname: Damiens
authors.forename: Bashir
authors.initials: B
authors.lastname: Alsharif
authors.forename: Ayman
authors.initials: A
authors.lastname: Ahmed
authors.forename: Elwaleed H O
authors.initials: EH
authors.lastname: Salih
authors.forename: Fayez T A
authors.initials: FT
authors.lastname: Ahmed
authors.forename: Abdoulaye
authors.initials: A
authors.lastname: Diabaté
authors.forename: Rosemary S
authors.initials: RS
authors.lastname: Lees
authors.forename: Jeremie R L
authors.initials: JR
authors.lastname: Gilles
authors.forename: Badria B
authors.initials: BB
authors.lastname: El Sayed
mesh_terms: D000818:Animals; D000852:Anopheles / Q000502:physiology* / Q000528:radiation effects*; D003163:Competitive Behavior / Q000528:radiation effects; D003625:Data Collection; D008124:Locomotion; D008297:Male; D010865:Pilot Projects; D012725:Sexual Behavior / Q000528:radiation effects*; D013242:Sterilization; D013397:Sudan; D016019:Survival Analysis