The developmental viability and sizes of sequentially oviposited eggs of Boophilus decoloratus and Boophilus geigyi.

The viability and sizes of eggs sequentially laid up to the 10th day of oviposition by engorged Boophilus decoloratus and Boophilus geigyi were studied. The average length and breadth of eggs laid on the 1st and 2nd days of oviposition were statistically greater than at subsequent ovipositions. The eclosion periods of eggs laid from 7th to 10th day of oviposition were shorter than those of eggs laid earlier by both Boophilus species. The percentage mortality of eggs of 9th and 10th day of oviposition was significantly higher than that of the earlier ovipositions. The numbers of larvae which engorged on rabbits after hatching from eggs of 7th-10th day ovipositions were significantly fewer than those which hatched from eggs of earlier ovipositions. It is concluded that eggs of early ovipositions of B. decoloratus and B. geigyi are more viable and survive longer than those of later ovipositions. It is also suggested that the shorter eclosion period of the eggs of later ovipositions is due to the process of embryogenesis which is gradual in the eggs of early ovipositions and faster in those of later ovipositions.