Variation in the hatching rate of larvae of four tick species from laboratory colonies.

The objective of this study was to evaluate the hatching percentage of tick larvae of Amblyomma sculptum, Dermacentor nitens, Rhipicephalus linnaei, and three strains of Rhipicephalus microplus. The egg masses laid by females of each tick species were weighed in different amounts (125, 250 and 500mg), placed in adapted 3 and 5 mL syringes, and incubated at 27°C and 80% relative humidity for 25 days for A. sculptum and 21 days for the remaining species. After this period, larval hatching rate was evaluated and data were analyzed through correlation and comparison between groups. The results showed that the average hatching rates varied from 27.9% to 42.2% for A. sculptum, 86.6% to 87.7% for D. nitens, 74.4% to 80.0% for R. linnaei, and R. microplus: 75.3% to 82.6% (UFRRJ strain), 64.6% to 72.2% (Mozo strain), and 71.8% to 75.2% (Porto Alegre strain). Although statistically significant differences were observed in the mean percentages between groups, the correlation was weak. We concluded that the weight of the egg masses and the volume of the containers did not significantly affect larval hatching.