Sigara falleni

Sigara falleni is a very common water bug which inhabits lakes, ponds, ditches and slow flowing rivers (often with S. dorsalis) and has a preference for neutral to alkaline water with fairly low levels of organic matter. It is capable of flight and is often taken at light traps, although a poor coloniser of new habitats. Adults overwinter and reproduce in the spring to give a new generation of adults by June. Another generation matures by August and the adults of a third generation overwinter. The stridulatory area on the front femur is poorly developed, but S. falleni is capable of a faint call.

Sigara-falleni-+-map

The map is based on records from NBN Gateway, with yellow dots showing pre 1990 records, reds dots 1990 – 2015 records and red on yellow dots overlapping records. A widespread species in the UK although more scattered in the west. It occurs Ireland where records are predominantly from the northern half of the island.

Although many species of Sigara may look similar at first glance, a combination of the following characters will generally be sufficient for identification: the length, the number of pale lines on the pronotum (and sometimes the shape of the pronotum) the pattern of dark and light lines on the forewing, the structure of the male pala  and the shape of the metasternal xiphus. Sigara falleni is one of the larger Sigara species (length 7 – 8 mm) with 7 or more pale lines on the pronotum, large male palae with two rows of pegs consisting of a longer diagonal row which points  to the inner end of the short outer row (see below), a blunt and short metasternal xiphus (see below) and the pointed sides of the pronotum forming acute angles (cf. S. distincta). The closely related species S. iactans, which is a recent immigrant to the UK, is very similar to S. falleni and is best distinguished by the form of the male pala.

      Sigara-falleni-pala-1     Sigara-falleni-xiphus

                                   Male pala                                       Metasternal xiphus