Food webs in the garden



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 Our Oxe-eye Sunflower Heliopsis helianthoides is about to bloom
Over the past several years Kiri and I have been furnishing our garden with plants native to Delaware.  We do this not only because we like these plants, but also to support local wildlife (especially insects of course).  While some pest insects can eat just about anything, most of our desirable insects can only feed on indigenous plant lineages that they co-evolved with.

As our summer flowers are gearing up for a brilliant June display, I have been spending more and more time checking  out the critters that have made their home in our yard.

Aphids give live birth
One of the most apparent visitors are these red aphids that are feeding on some plant stems.  Aphids can reproduce with or without sex, and they are viviparous - having live birth.  This helps them to increase in number very quickly, and sometimes an adult aphid can be seen with a whole row of it's clonal offspring feeding right behind it:

Goldenglow aphids Uroleucon rudbeckiae
Despite their sucking the juices out of our plants, these aphids are a welcome visitor, and I don't worry much about them killing my flowers.  Kiri noticed that while the aphids are host specific, feeding only on our Heliopsis, they do not feed on every plant of that species.  The different plants have slightly different genes, and the aphids prefer certain genotypes on which they are the most successful.  On the preferred plants, they have reached very high numbers, but they have also attracted large numbers of insect predators that attack aphids.
A battle is unfolding amongst our wildflowers as these predators go after the huge aphid colonies - I don't think it's going well for the squishy red plant-suckers.  More on that to follow!
Our garden provides wildlife habitat and a place for me to watch predators and prey!

3 comments:

Morgan Jackson at: May 28, 2012 at 11:59 PM said...

The photo of viviparous birth is an absolutely wicked shot! Well done!

Samantha B at: May 29, 2012 at 8:52 AM said...

Nice shots and beautiful garden! I love this blog.

Brian Cutting at: May 30, 2012 at 7:26 AM said...

Thanks for the comments and encouragement! I was on the fence about that aphid shot, but now I'm glad I used it!

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