STUDIES ON THE EFFECT OF INFECTION BY BABESIA SP. ON OVIPOSITION OF BOOPHILUS-MICROPLUS ENGORGED FEMALES NATURALLY INFECTED IN THE MEXICAN TROPICS

Three hundred and fifteen engorged female Boophilus microplus ticks (w eight 210-250 mg) naturally infected with Babesia sp., in the Mexican tropics were monitored for egg production. Haemolymph samples were tak en from each tick on the 5th day to the 16th day after collection to d etect and estimate the infection with Babesia sp. kinetes. All ticks w ere held in darkness at 27+/-1.5 degrees C and 85-86% relative humidit y. The infection rate of Babesia sp. was 20.3% (64/315). Fifteen ticks were considered heavily infected and 49 lightly infected. The pre-ovi position periods were 3.17+/-0.37, 3.18+/-0.25 and 3.17+/-0.25 days fo r heavily infected, lightly infected and uninfected, respectively (P>0 .05). The numbers of eggs laid on the first day of oviposition were 25 2+/-53, 235+/-37, 54+/-23 for heavily infected, lightly infected and u ninfected, respectively. There was a statistically significant differe nce between infected (heavily and lightly) and uninfected (P<0.05) tic ks. Oviposition periods were 9.60+/-0.81, 9.50+/-0.72 and 9.36+/-0.48 days for heavily infected. Lightly infected and uninfected, respective ly (P>0.05). The average egg production of heavily infected, lightly i nfected and uninfected female ticks was 2640+/-103, 2574+/-123 and 284 1+/-170 (P>0.05), respectively. These data imply that there is an adap tative tolerance between Babesia sp., and B. microplus under field con ditions in the Mexican tropics. (C) 1998 Elsevier Science B.V. All rig hts reserved.