title: A study of the diapausing behaviour of Rhipicephalus appendiculatus and R. zambeziensis under quasi-natural conditions in Zambia.
abstract: The diapausing behaviour of Rhipicephalus appendiculatus was studied under quasi-natural conditions in the Eastern Province of Zambia. Newly-moulted adults of ticks indigenous to the study area entered a behavioural diapause when exposed to daylengths below a critical photoperiod, provisionally a daylength between 11 h 20 min and 11 h 45 min. In the Eastern Province of Zambia the diapause was apparently not terminated by a long-day signal, but by a weakening of the photoperiodic maintenance of the diapause because of increasing age of the ticks. Adults of a reference stock indigenous to Kenya also entered a diapause when exposed to daylengths below the same threshold and maintained this diapause for the same length of time. Adults of a reference stock of Rhipicephalus zambeziensis indigenous to Zimbabwe did not enter a diapause when exposed to the same daylengths. The relevance of the findings is discussed in relation to the distributions of the two species.
authors.affiliation: Department of Tropical Animal Health and Production, Institute of Tropical Medicine, Antwerp, Belgium.
authors.forename: D L
authors.initials: DL
authors.lastname: Berkvens
authors.forename: R G
authors.initials: RG
authors.lastname: Pegram
authors.forename: J R
authors.initials: JR
authors.lastname: Brandt
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D005260:Female; D006813:Humidity; D017440:Photoperiod; D011817:Rabbits; D012621:Seasons; D013987:Ticks / Q000502:physiology*; D015024:Zambia