Out of Africa: evidence of the obligate mutualism between long corolla tubed plant and long-tongued fly in the Himalayas

1 Mutualism between long corolla tubed plants and their potential pollinators,long-tongued flies, is a classic example of coevolution, but to date, has onlybeen reported from the regions of southern Africa. Many plant species fromthe Himalayas also show botanical characteristics that could be consistentwith pollination by long-tongued flies. Here, we seek the evidence of the"long-tongued-long tubed fly/flower" mutualism out of Africa, in a differentcontinent and climatic region, the Himalayas.2 Floral traits of Himalayan region endemic alpine genus, Roscoea , indicatepossible mutualism with long-tongued flies for pollination success; however,effective pollinators of this genus are yet unknown. This study investigateswhether long-tongued flies and Roscoea purpurea in Nepal Himalayas showexclusive mutualism for their survival/reproduction.3 We made extensive observations of floral visitors of R. purpurea and foodsource of Philoliche longirostris across their wide ranges of populations inNepal Himalayas for three consecutive years (2012-2014). To confirm theobligate reliance of R. purpurea upon P. longirostris for pollination success,manipulated pollination experiments were conducted at two populations for2 years. Similarly foraging behavior, visitation frequency, and pollinationefficiency of P. longirostris were assessed at two populations for 2 years, andits contribution for the reproductive success of R. purpurea was evaluated.Our results indicate that R. purpurea is self-compatible but lacks autono-mous selfing and obligatorily relies on P. longirostris for reproductive suc-cess. Across all populations, P. longirostris was observed as an exclusive andhighly efficient pollinator of R. purpurea, while P. longirostris exclusivelydepends up on R. purpurea for food source.4 Out of Africa, this study provides the first evidence of long-tongued fly polli-nation system and indicates the possibili