Intraspecific diversity in parasites with heteroxenous life cycles is guided by reproduction mode, host vagility and dispersal, transmission features and many other factors. Studies of these factors in Digenea have highlighted several important patterns. However, little is known about intraspecific variation for digeneans in the marine Arctic ecosystems. Here we analyse an extended dataset of partial cox1 and nadh1 sequences for Tristriata anatis (Notocotylidae) and confirm the preliminary findings on its distribution across Eurasia. Haplotypes are not shared between Europe and the North Pacific, suggesting a lack of current connection between these populations. Periwinkle distribution and anatid migration routes are consistent with such a structure of haplotype network. The North Pacific population appears ancestral, with later expansion of T. anatis to the North Atlantic. Here the parasite circulates widely, but the direction of haplotype transfer from the north-east to the south-west is more likely than the opposite. In the eastern Barents Sea, the local transmission hotspot is favoured.

This is the first report on increasing yield and nutritional content of snake melon (Cucumis melo L. var. flexuosus) by exploiting intraspecific genetic variation of genetically diverse melons. Inbred snake melon ‘Punjab Long melon 1’ (PLM1) was hybridized with five genetically diverse inbred melons: KP 7 (var. momordica), AM 72 (var. acidulus), ‘Arya 1’ (var. chate), 04-02 (var. tibish) and ‘Punjab Wanga’ (unknown botanical variety). The parents and hybrids were evaluated at three locations for nine traits. Hybrids PLM1 × 04-02 and PLM1 × ‘Punjab Wanga’ exhibited significant (P0.05) heterosis for the number of marketable fruits per plant, and ascorbic acid and carotenoid contents of marketable fruits.

Increasing interaction among specialists in the field of biosystematics so as to facilitate better identification services is suggested, taking into consideration the increasing intraspecific diversity resulting in recognizable “biotypes”. The need for a more comprehensive idea of intraspecific diversity in different insect groups is also indicated.