Pollen Eating. Sphaerophoria scripta, Long Hoverfly, on Field Bindweed, Convolvulus arvensis, Océ-weerd, Meuse Corridor, Venlo, The Netherlands
You may know that its outer 'skin' is so hard and durable that pollen can survive even millions of years. Thus it can be used to date geological and archaeological finds, giving insight, for example, into the processes of climate change.
How then can an insect such as our Long Hoverfly eating pollen access the nutrients inside such a grain?
Well, the pollen grain is 'tricked' - as Christopher Hassall says. When pollen lands on a flower's stigma, the sticky, sweet surface signals it to open a germination pore in that hard outer covering. Through it a pollen tube grows down the style to the ovary to fertilise an ovule which if all goes well will become a seed.
Now, grains of pollen ingested by our Hoverfly into its mid-gut land in a similar environment with nectar and enzymes. They're induced to open a germination pore which gives those enzymes extraction access to pollen's nutrients, thus nourishing our insect and allowing it further life and more pollination work. The empty pollen grains are then normally evacuated.
The photo shows a Hoverfly licking a purple stamen of Field Bindweed for its white pollen. In the middle is the flower's stigma and pistil.
Pollen Eating. Sphaerophoria scripta, Long Hoverfly, on Field Bindweed, Convolvulus arvensis, Océ-weerd, Meuse Corridor, Venlo, The Netherlands
You may know that its outer 'skin' is so hard and durable that pollen can survive even millions of years. Thus it can be used to date geological and archaeological finds, giving insight, for example, into the processes of climate change.
How then can an insect such as our Long Hoverfly eating pollen access the nutrients inside such a grain?
Well, the pollen grain is 'tricked' - as Christopher Hassall says. When pollen lands on a flower's stigma, the sticky, sweet surface signals it to open a germination pore in that hard outer covering. Through it a pollen tube grows down the style to the ovary to fertilise an ovule which if all goes well will become a seed.
Now, grains of pollen ingested by our Hoverfly into its mid-gut land in a similar environment with nectar and enzymes. They're induced to open a germination pore which gives those enzymes extraction access to pollen's nutrients, thus nourishing our insect and allowing it further life and more pollination work. The empty pollen grains are then normally evacuated.
The photo shows a Hoverfly licking a purple stamen of Field Bindweed for its white pollen. In the middle is the flower's stigma and pistil.