Sperm competition in the family Libellulidae (Anisoptera) with special reference to Crocothemis erythraea (Brulle) and Orthetrum cancellatum (L.)

Examination of the behavior and of the male and female genital structure of a number of libellulid dragonflies has suggested that some may be defined as “removers” while others are probably “repositioners”. The latter are those species which are believed to gain sperm precedence mainly by repositioning sperm already present in the female before inserting their own, thereby gaining a last-infirst-out precedence. The former, on the other hand, tend to spend longer in copulation and possess penes armed with barbed flagella and/or processes. They are thought to remove sperm from females before introducing their own. Some species probably depend on a strategy which may combine repositioning with removing. Crocothemis erythraea and Orthetrum cancellatum are examined in this context.