title: Leg loss inLutzomyia longipalpis(Diptera: Psychodidae) due to pyrethroid exposure: Toxic effect or defense by autotomy?
abstract: OBJECTIVE
  Phlebotomine sandflies lose their legs after exposure to pyrethroids. In some insects leg loss helps to defend them from intoxication and predation, a phenomenon known as autotomy. A field observation has shown that sandflies that have lost some legs are still able to blood-feed. The aims of the study were to determine whether leg loss in sandflies, after exposure to deltamethrin, is due to autotomy and to establish the effect of the leg loss on blood-feeding.
  
  
  METHODS
  Two experiments were carried out with Lutzomyia longipalpis: (i) Females were individually exposed to a sublethal time of deltamethrin and mortality and the number of leg loss were recorded; and (ii) Groups of females with complete legs or with 1-3 legs lost due to pyrethroid exposure were offered a blood meal and percentages of blood-fed and fully-fed females were recorded.
  
  
  RESULTS
  Most females lost a median of 1 leg within 1-48 h post-exposure to deltamethrin. Mortality (after 24 h) was significantly higher for exposed females with lost legs (31.1%), compared to exposed females with complete legs (7.3%), and there were no differences in mortality between females with complete legs and the control (unexposed females). There were no differences between the three treatments in the percentages of blood-fed and fully-fed females.
  
  
  CONCLUSIONS
  Leg loss in sandflies is a toxic effect of pyrethroids and there was no evidence of autotomy. The loss of up to three legs after exposure to pyrethroids does not affect blood-feeding behaviour in laboratory and probably also in wild conditions.
authors.affiliation: Entomology Group, National Institute of Health, Bogotá, Colombia.
authors.forename: E
authors.initials: E
authors.lastname: Santamaría
authors.affiliation: Entomology Group, National Institute of Health, Bogotá, Colombia.
authors.forename: O L
authors.initials: OL
authors.lastname: Cabrera
authors.affiliation: Entomology Group, National Institute of Health, Bogotá, Colombia.
authors.forename: J
authors.initials: J
authors.lastname: Avendaño
authors.affiliation: Entomology Group, National Institute of Health, Bogotá; Entomology and Vector Borne Diseases Group, De La Salle University, Bogotá, Colombia.
authors.forename: R H
authors.initials: RH
authors.lastname: Pardo
mesh_terms: D000818:Animals; D005121:Extremities / Q000033:anatomy & histology; D005247:Feeding Behavior; D005260:Female; D007306:Insecticides / Q000633:toxicity*; D009570:Nitriles / Q000633:toxicity*; D011576:Psychodidae / Q000033:anatomy & histology / Q000187:drug effects*; D011722:Pyrethrins / Q000633:toxicity*; D016019:Survival Analysis
chemical_list: D007306:Insecticides; D009570:Nitriles; D011722:Pyrethrins; C017180:decamethrin