Ecological characteristics of certain species of horse flies (Diptera: Tabanidae) in Kopacki Rit Nature Park, Croatia

Background and Purpose: The present study had two aims: the first, to document the fauna of horseflies in the Kopacki rit Nature Park, and the second, to supply data on the ecology of the Most common Species. Materials and Methods: Periodical collections were carried out for two consecutive years (1998 and 1999) at 12 localities that cover 3 fields on the UTM grid of Croatia. To sample horse flies, three linen Malaise traps, i.e. red, blue and black, three CDC (Center for Disease Control traps) and entomological net were used. Dry ice (CO2) was used as an attractant. Results and Conclusions: In the Kopacki rit area, 4,033 horse flies belonging to 25 species were trapped. Hybomitra ciureai (Seguy, 1937) was the most common (26.6%) followed by Tabanus bromius L. 1758, (21.3%) and Haematopota pluvialis (L. 1758) (17.5%). These three species account for 65.3% of the tabanids collected in Kopacki rit. The abundance of these species depends on the size of the area flooded because tabanid larvae live in the water or in moist ground near the water and even in the adults remain near their breeding sites. In 1998, the abundance of these three species peaked in June. In 1999, only Hybomitra ciureai and Haemtopota pluvialis were present throughout the horse fly flight season and had two pea’s of abundance (in May and July). The longest flight period (126 days) was recorded in 1999 for Hybomitra ciureai. Horseflies have been clustered into three zoogeographical groups: the Boreal - Eurasian group (19 sp.), the Afro - Eurasian arid group (2sp.) and the South European group (4 sp.).