Photo by Nicholas A. Tonelli licensed under CC BY 2.0

There are few things better than hiking on a hot summer day and coming across a big patch of ripe blackberries and/or raspberries. If you're anything like me then you promptly gorge yourself on handfuls of these sweet aggregate fruits. However, the genus Rubus never gives its fruit away all at once. Although this may seem like a pain for us humans, there is good reason for it.

The answer to this ripening strategy lies in the seed dispersers. A multitude of animals feed on the fruit of the genus Rubus but by and large the best seed dispersers are birds. Rubus fruits begin to ripen around the time when many birds are beginning to ramp up their food intake to prep for either migration or the long winter to come. Regardless, birds can travel great distances and thus can spread seeds via their droppings wherever they go.

If Rubus were to ripen their fruit all at once, only a handful of birds would make use of the entire seasons reproductive effort. This means that all the seeds of an individual plant would likely fall to the ground in the general vicinity of the parent. By sequentially ripening their fruit, Rubus ensure that their seeds will not only be available for a few weeks to a couple of months, it also ensures that birds, as well as many other animals, will be involved in the distribution of seeds. It's not just the genus Rubus that does this either. Plenty of other berry producing plants ripen their fruitss sequentially. It is a wonderfully successful strategy to persuade mobile organisms to do exactly what the plants require.

Photo Credit: Nicholas A. Tonelli (http://bit.ly/1q6Gvja)

Further Reading:
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