The Biology of Tipula subnodicornis Zetterstedt, with Comparative Observations on Tipula paludosa Meigen

Abstract

The study of the biology of crane-flies belonging to the genus Tipula has been mainly restricted to species of economic importance. T. paludosa, which occurs commonly on cultivated land, has been studied by a number of authors. Rennie (1916, 1917) studied the life cycle of this species and discussed its economic importance. Bodenheimer (1923, 1924) made an extensive study of the structure and biology of a crane-fly referred to as T. oleracea Meigen. He did not distinguish between T. oleracea and T. paludosa, but his figures (and personal communication) indicate that most, if not all, of his material was T. paludosa. Sellke (1936) has made a laboratory study of three species of the T. oleracea group, T. oleracea, T. paludosa and T. fusca Staeger (== T. czizeki de Jong). Barnes (1937) reared larvae of T. paludosa in the laboratory and studied oviposition under laboratory conditions. More recently, Maercks (1939, 1943) studied the Tipulidae of agricultural land in northern Germ4ny, paying particular attention to T. paludosa and factors which may be of importance in influencing the numbers of larvae. Apart from the statement of Audcent (1932) that in Great Britain T. subnodicornis is common on cotton-grass (Eriophorum) moors, little is known of its biology. Tipulidae have usually been studied in the laboratory and few observations have been made under field conditions. Maercks (1939, 1943) sampled for larvae in agricultural land in north Germany, but the populations were only sampled twice in each generation. He also studied the effects of desiccation on the eggs and larval instars of Tipula paludosa and demonstrated that newly laid eggs and the first instar larvae were the stages which were most susceptible to desiccation. Recently, Loughlin (1958a) has shown that eggs of T. oleracea (a species which is closely related to T. paludosa but which lays relatively smaller eggs) are capable of withstanding temporary desiccation beyond the 'dimpling' stage. Rennie (1917) also draws attention to the susceptibility of early stages of T. paludosa to desiccation and associated wet autumns