Growing complimentary crops and nutritionally rewarding cultivars to sustain insect pollinators and crop pollination on farms

Ongoing pollinator declines threaten food security and impair crop yields. A major driver of these declines is lack of sufficient flowers in farmland.
Mass-flowering crops provide abundant resources for some pollinators for short periods, but there are large gaps on many farms when no crop is in flower.

The student will investigate whether pollinator declines may be mitigated by choice of appropriate crops and/or cultivars, over time, at a farm scale.

Oilseed rape, apples, strawberries and raspberries provide nectar and pollen for pollinators, but little attention has been paid to the relative rewards offered by the different cultivars. For example, some varieties of oilseed rape and apple are more attractive to pollinators but the reasons for this have not been investigated. Although visual and olfactory cues likely play a role in long to intermediate range attraction, bees in particular repeatedly return to the same floral resources. Presumably, some varieties provide better resource, e.g. nectar sugars and/or nutritional value of pollen. Growing more rewarding cultivars should benefit the crop, through repeated pollination visits, and benefit pollinator populations by providing higher value food for off-spring. It is thus surprising that plant breeders do not routinely consider attractiveness to pollinators when developing new cultivars, and few attempts have been made to evaluate the relative rewards provided by different cultivars.

The student will quantify the floral resources (nectar volume, sugar concentration, protein, petal size) provided by the main commercial cultivars of oilseed rape, apple, pear, blackcurrant, raspberry and strawberry, and quantify the identity and abundance of pollinators attracted to each. They will map the phenology of these and other flowering crops commonly grown in SE England, with a view to providing continuity of flowering at a landscape scale, with the aim of providing recommendations for farmers and fruit growers.