| The tick Ixodes aragaoi Fonseca, 1935 occurs at Brazil and Uruguay, where its immature stages feed mainly on small rodents, and adults on deer and cattle. In July 2011, four engorged females of I. aragaoi were collected from Rocha department in Uruguay, brought to the laboratory where a colony was established and used for biological studies. Free-living tick stages were maintained in an incubator at 23°C with a relative humidity >95%. During two tick generations in the laboratory, 41 rodents of the species Calomys callosus with 100-200 larvae and 30 nymphs were each infested. For adult ticks, 4 New Zealand rabbits were each infested with 10 couples of I. aragaoi. Grouping data from the two lab generations, larval, nymphal, and female mean feeding periods were 5.5±0.7, 6.0±2.8, and 13±0.8 days, respectively. Feeding success (the proportion of unfed ticks that successfully engorged) was 64% for larvae, 44% for nymphs, and 75% for females. Overall, 92.6% of the engorged larvae detached from hosts during daytime (from 7a.m. to 7p.m.), whereas 7.4% detached during the night (from 7p.m. to 7a.m.). For engorged nymphs, 58.3% detached during daytime, and 41.7% during the night. Mean larval premolt periods at 23°C, 25°C and 27°C were 42.2±4.4, 34±2.9 and 33.5±2.6 days, respectively. Mean nymphal premolt periods at 23°C, 25°C and 27°C were 41.4±4.4, 39.3±3.1 and 35.2±4.0 days, respectively. Mean values for female reproductive parameters at 23°C were: engorged female weight: 98.7mg; preoviposition period: 12.8±2.4 days; egg mass weight per female: 21.3mg; egg incubation period: 58.5±1.7 days. Unfed larvae were obtained at low proportions from most of the egg masses. |
