Effect of egg clustering on the fitness of Rhipicephalus sanguineus larvae.

Several biological aspects of Rhipicephalus sanguineus have been studied, but scant information is available on the effect of egg clustering on incubation period and larval survival. Herein, R. sanguineus eggs were separated in groups composed by 1 (GI), 10 (GII), 50 (GIII), 100 (GIV), 500 (GV) and 1,000 (GVI) eggs (10 replicates), and incubation and larval survival period were recorded. No correlation was observed between the amount of egg batches and hatching percentage. Larvae from GI hatched in a longer time (mean 17 days), than those of other groups (mean 14.9 days). This difference was significant in eggs from group GI vs. GV and GI vs. GVI (P<0.05). Conversely, GI displayed a shorter survival period (mean 28.7 days) compared with other groups (P<0.01). The maximum survival time was recorded in GV (mean 49.8 days). Data suggest that R. sanguineus egg clustering affects incubation period and larval survival.