title: Feeding nymphs of Hyalomma truncatum (Acari: Ixodidae) on guinea pigs previously exposed to nymphs.
abstract: The ability of nymphal Hyalomma truncatum Koch to feed on guinea pigs previously exposed to nymphal ticks was studied by measuring the percentage of ticks engorging and molting, their engorged weight, and hemoglobin content. Four guinea pigs were infested with 20, 40, 80, and 200 nymphs, respectively, on three occasions at 21-d intervals, followed by a fourth infestation after another 21-d interval with 100 nymphs. Guinea pigs originally infested with 20 and 80 nymphs were infested a fifth time with 100 nymphs 3 mo after the fourth infestation. Guinea pigs originally infested with 40 and 200 nymphs were infested a fifth time with 100 nymphs 6 mo after the fourth infestation. There was a significant decrease, below infestation I levels, in the number of ticks engorging on each guinea pig during infestations IV and V. Whereas all nymphs molted after infestation I, the percentage of nymphs molting after infestation V ranged from 0 to 34%. For ticks infested on each of the guinea pigs, the percentage molting after infestations III-V were significantly lower than those observed after infestation I. A significant decrease in the mean weight of engorged ticks was observed starting at infestation III. Mean hemoglobin content of ticks declined significantly at infestation II. The response elicited by feeding nymphs appeared to last at least 6 mo.
authors.affiliation: Department of Entomology, Armed Forces Research Institute for Medical Sciences (AFRIMS), APO AP 96546.
authors.forename: K J
authors.initials: KJ
authors.lastname: Linthicum
authors.forename: T M
authors.initials: TM
authors.lastname: Logan
mesh_terms: D000818:Animals; D005247:Feeding Behavior; D005260:Female; D006168:Guinea Pigs / Q000469:parasitology*; D006454:Hemoglobins / Q000032:analysis; D007113:Immunity, Innate; D008675:Metamorphosis, Biological; D009758:Nymph / Q000502:physiology; D013984:Tick Infestations; D013987:Ticks / Q000502:physiology*
chemical_list: D006454:Hemoglobins