Seasonal Distribution, Diurnal Periodicity and Physiological Age of Host-Seeking Tabanids (Diptera: Tabanidae)

Abstract

<p>Host-seeking activity, for most tabanid species, reached a maximum in mid-afternoon. The diurnal periodicities of Chrysops vittatus and C. univittatus, however, were bimodal, with activity peaks in the morning and late afternoon. Air temperature and rainfall were the meteorological parameters having the greatest influence on the diurnal activity pattern.</p> <p>Host-seeking activity began at 13°C and reached a maximum at temperatures between 26 and 28°C. The effect of solar radiation on activity varied with the air temperature.</p> <p>Physiological age studios showed that few females completed two gonotrophic cycles. Tabanus rainwardtii was proven to be autogenous. Autogeny is suspected for C. niger. C. cuclux, C. cincticornis, T. guinquevittatus and Hybomitra lasiophthalma are thought to be capable of facultative autogeny. Other species (C. moechus, C. vittatus, C. univittatus, T. similis, T. lineola, C. aberrans, H. epistates and C. callidus) were anautogenous.</p> <p>Parous females formed a greater percentage of the host-seeking population in the afternoon than in the morning.</p>