title: Ethanol preference in Drosophila melanogaster is driven by its caloric value.
abstract: BACKGROUND
  Perhaps the most difficult thing to ascertain concerning the behavior of another animal is its motivation. The motivation underlying the preference of Drosophila melanogaster for ethanol (EtOH)-rich food has long been ascribed to its value as a food. A recently introduced idea is that, as in humans, the pharmacological effects of EtOH also motivate the fly to choose EtOH-rich food over nonalcoholic food.
  
  
  METHODS
  Flies are given a choice between pipets that contain liquid food and liquid food supplemented with EtOH. In some experiments, carbohydrates are added to the non-EtOH-containing food to balance the calories for EtOH.
  
  
  RESULTS
  We confirm that D. melanogaster indeed prefer food that is supplemented with EtOH. However, if the alternative food choice is isocaloric, D. melanogaster usually do not show any preference for a 10% EtOH solution. Even after EtOH preference has been established, it can be completely reversed if the alternative food is calorically supplemented. This occurs even when the carbohydrate solution used to balance calories is not gustatorily attractive. Furthermore, if the alternative food contains more calories than the EtOH food, the flies will prefer the non-EtOH food. We go on to show that during the preference assay that EtOH in the fly does not exceed 4 mM, which in mammals is a nonintoxicating dose.
  
  
  CONCLUSIONS
  We conclude that preference for EtOH in this assay arises not from the pharmacological effects of EtOH but rather because of its nutritive value.
authors.affiliation: Waggoner Center for Alcohol and Addiction Research , Section of Neurobiology, The University of Texas at Austin, TX 78712, USA.
authors.forename: Jascha B
authors.initials: JB
authors.lastname: Pohl
authors.forename: Brett A
authors.initials: BA
authors.lastname: Baldwin
authors.forename: Boingoc L
authors.initials: BL
authors.lastname: Dinh
authors.forename: Pinkey
authors.initials: P
authors.lastname: Rahman
authors.forename: Dustin
authors.initials: D
authors.lastname: Smerek
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Prado
authors.forename: Nyssa
authors.initials: N
authors.lastname: Sherazee
authors.forename: Nigel S
authors.initials: NS
authors.lastname: Atkinson
mesh_terms: D000428:Alcohol Drinking / Q000378:metabolism; D000818:Animals; D002755:Choice Behavior / Q000187:drug effects* / Q000502:physiology; D004331:Drosophila melanogaster / Q000187:drug effects* / Q000378:metabolism; D002149:Energy Intake / Q000187:drug effects* / Q000502:physiology; D000431:Ethanol / Q000008:administration & dosage* / Q000378:metabolism; D005260:Female; D005518:Food Preferences / Q000187:drug effects* / Q000502:physiology
chemical_list: D000431:Ethanol