Oviposition of the Gulf Coast Tick1

Abstract

Female Amblyomma maculatum Koch engorged on bovines and were held in the laboratory at 27°C, 70-98% RH, and a photocycle of 12 hr light: 12 hr dark. Thirty-fIve females were disturbed daily by removal of eggs, and 50 others were allowed to oviposit without being disturbed. Weights of females and number of eggs/♀ did not differ significantly in the 2 groups. Average weight of a newly laid egg was 52 μg; that of an egg from an egg mass after oviposition was complete (but before hatching) was 50 µg. For females which were disturbed daily, the number of eggs laid (avg 9963, range 0-17,592) was highly significantly corre!ated with the weight of the female (avg 0.973)g, range 0.390-1.443 g); the regression of number of eggs on weight of females was YD = 10,804 &-548. When females were undisturbed, the number of eggs laid (avg 9130, range 0-18,218) was also highly significantly correlated with weight of the female (avg 0.919 g, range 0.360-1.439 g); the regression was YUD = 13,878 &-3621. An index of reproduction efficiency (no. eggs/wt ♀), established to relate the capacity of the females to produce eggs to their body weight, and an index of conversion efficiency (wt eggs/wt ♀), established to relate the ability of females to convert body weight into egg weight to their body weight, did not differ between the 2 groups and was not correlated with the weight of females. All females showed a highly significant negative correlation of the preoviposition period (avg 4.15 days, range 1-9 days) with the weight of the female. Peak average daily oviposition was 1059 eggs/♀ on the 6th day of oviposition; an average of > 900 eggs/♀ were laid on days 4-8 of oviposition. The length of the oviposition period (avg 18.1 days, range 0-26 days) was highly significantly correlated with the number of eggs but was not correlated with the weight of the female. The average minimum incubation period was 21.9 days (range 19-24 days), and eggs laid during the 1st 2/3 of the oviposition period had a slightly shorter minimum incubation than those laid during the final 1/3 of the oviposition period.