Sizes and developmental viability of sequentially oviposited eggs of dog ticks: Rhipiceplialus sanguineus and liaemap/iysalis leachi leachi

Abstract

Sizes and developmental viability of sequentially oviposited eggs of up to 12"' day oviposition by dog licks Rhipiceplialus sanguineus and Ilaemaphysalis leachi leachi wore studied. The mean length and breadth of eggs oviposited on days I and 2 were greater (0.45 + 0.111 and 0.44 + 0.042) than those of subsequent oppositions. The eclosion periods of eggs laid from 7"' to 12"' day of oviposition were progressively shorter (17, 16, 14 and 19, 17, 0 days) than those of eggs laid on days 1 and 2 (20 and 22 days) by R. sanguineus and //. leachi leachi, respectively. The percentage mortality of eggs of days 11 and 12 oviposition (70.3% and 100%) was significantly higher than that of earlier ovipositions (9.6% and 31.7%) for R. sanguineus and II. leachi leachi, respectively. The numbers of larvae which engorged on rabbits after hatching from eggs of 11"' and 12"' day oviposition (43 and 0) were significantly fewer than those which hatched from eggs of days 1 and 2 (79 and 63) for R. sanguineus and II. leachi leachi, respectively.A total of 383 larvae of R. sanguineus engorged on rabbits compared to 225 larvae of II. leachi leachi. It is concluded that eggs of early ovipositions of R. sanguineus and //. leachi leachi are longer and wider and more viable than those laid later in the oviposition cycle. The significance of these findings in terms of hatchability of eggs is discussed.