Tropical cucumbers in the genus Gurania are the home of Blepharoneura flies. Gurania plants begin their life as males, then switch to be females!

Early in life the vine invests energy in climbing high and capturing as much light as possible. During this time only male flowers are produced.

When the plant has grown high enough and big enough, the end of the vine stops creeping upwards and hangs down loose. On the end of the loose vine female flowers can finally grow.

Why do female Gurania flowers hang loose? The bats that disperse the fruit find it via echolocation. If the fruit didn't hang loose in an open space, the bats wouldn't be able to find it.

(above) Male inflorescence with a Blepharoneura fly

(below) Hanging female flowers

(both pictures above) Fruit bat eating Gurania fruit