Blood Feeding, Oögenesis, and Oviposition by Tabanus nigrovittatus1 in the Laboratory

Parous Tabanus nigrovittatus Macquart were collected from canopy or box traps in Connecticut and Massachusetts salt marshes and were presented warmed (31°C-37°C) citrated beef blood in the laboratory. Females ingested between 3.2–53.7 mg of blood. Pre-fed body weights varied (19.9–53.4mg) but were significantly correlated with sizes of blood meals. Quantities of ingested blood were significantly correlated with fecundity. Oöcytes matured 7–10 days after engorgement. There was no significant difference between anautogenous fecundity ( $\bar x$ = 154.8) and autogenous egg production ( $\bar x$ = 168.9). During oviposition, females cemented the eggs together and to the substrate; eggs were arranged in 2 tiers and hatched within 1 wk of deposition. Hatch rates for 42 egg masses averaged 40.3% and ranged from 1.3–95.5%. No more than 1 follicular relic (=dilatation) could be found per ovariole in 235 host-seeking individuals or in 8 females that had completed 2 ovarian cycles (anautogenously) in the laboratory. Thus, the application of Polovodova's method to field-captured T. nigrovittatus is likely to yield inaccurate estimates of physiological age.