Annoying insects?

Mayfly have featured in this blog several times, having spent over a year as larvae, eating algae those that have survived being eaten by fish, crayfish and dragonfly larvae emerge from the river in late spring and become adults.  With no mouth or stomach closeup they appear almost alien.
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The e lucky one ones will live for a day during which they will attract a mate, reproduce, lay eggs and die:
Whilst, the unlucky ones just become part of the food chain. Having survived them as nymphs, adult mayfly are a target for adult dragonflies and damselflies, who find the males easy prey as they bounce up and down in the air trying to attract a mate.
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These along, with the mayfly are prey for swifts who have returned to Abingdon after spending the winter in Africa to raise their young. Darting above the river at high speed, making the most of this abundance of winged insects (making them rather tricky to photograph).
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The swifts - along with the damselflies, dragonflies and the unfortunate mayfly - are in turn prey to a small bird the size of the kestrel with the flying pattern of a swift; these are hobbies that have also returned from Africa and on occasions can be seen darting above the Ock:.

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Although when swarming in large numbers they can be an annoyance on a early summer walk, the mayfly in their larval and adult forms are probably one of the most important creatures on the river and without them we wouldn't have the dragonflies, birds, fish and otters that make the Ock such an enjoyable place to walk.