COMPARATIVE REPRODUCTION AND NONPARASITIC DEVELOPMENT OF BOOPHILUS-MICROPLUS AND HYBRIDIZED BOOPHILUS TICKS (ACARI, IXODIDAE) UNDER NATURALFIELD CONDITIONS IN SUBTROPICAL SOUTH-TEXAS

The reproductive biology and nonparasitic development of Boophilus mic roplus (Canestrini) and hybridized Boophilus ticks (B. annulatus (Say) male x B. microplus female) held under natural field conditions in so uth Texas throughout the year were compared. Comparisons between the t wo types of ticks indicated that the ovipositional biology (percentage of ovipositing females and number of eggs laid) of the females favore d hybrid ticks during some months and B. microplus ticks during other months. However, on a yearlong basis, there was virtually no differenc e in the percentage of ovipositing females or in the number of eggs de posited by hybrid females as compared to B. microplus. The duration of each nonparasitic development period (preoviposition period, incubati on period of eggs, and larval longevity) showed that both types of tic ks had very similar developmental and survival rates during the year. Generally the difference in duration of each of the nonparasitic param eters was <8 days, leading to a high degree of synchrony of the nonpar asitic developmental rates between the two types of ticks. On the othe r hand, egg hatchability of hybrid ticks was consistently lower than p ure-strain B. microplus throughout the year with significantly lower h atch rates occuring in April, July, August, October, and November. Thu s, results obtained on percentage of ovipositing females, number of eg gs laid, preoviposition period, incubation period of eggs, and larval longevity provide positive encouragement for the possible use of steri le hybrid males as a means of eliminating a native B. microplus popula tion. In contrast, results of the egg hatchability of the two types of ticks indicate that the selective advantage afforded to B. microplus could have an adverse affect on the success of a sterile hybrid male p rogram by making the number of hybrid ticks necessary to eliminate a n ative population prohibitively high.