Sunday, 23 May 2010

Roses are Red, Greenfly are Pink?...

The recent warm weather has brought out clouds of Greenfly. It seems that most of them have taken to living on my roses.

It's always confused me that although you see loads of Greenfly swarming about, when you look on the plants, very often the don't appear to have wings.

It turns out that not all Aphids have wings. When food is short or conditions dictate, the females give birth to winged individuals that can go in search of new feeding areas. As well as laying eggs in autumn to overwinter, females can produce several offspring per day without mating. No wonder there's so many!

The local birds do their best picking them off but the Aphids have their own defence. The two little tubes sticking up from their back are called Cornicles, and they use them to expel an unpleasant waxy substance to put off their attackers.

Greenfly aren't always green. They range from green to pink as some have the ability to synthetically produce carotenoids (a plant pigment). They have acquired this adaption through a process of horizontal gene transfer (genetic splicing) from ingesting fungi which protect themselves from sunlight using artificially created carotenoids.




Aphids love to suck the sugary sap out of plants. Although they can get all the energy they need from the sap, they need to drink even more in order to obtain the 'building blocks' of life. The excess sap is pooed out as Honeydew. Ants take advantage of this ready food supply and even 'farm' the Aphids. The ants will actively defend the aphids, and even move them about to new feeding areas to maximise output. They milk the little chaps by rubbing their backs with their antennae to make them exude honeydew which they then carry off.

Very often simply viewed as a pest, Greenfly are quite fascinating little creatures. They mean no harm, and I think look rather cute. My roses however are suffering. I don't want to poison the chappys so I'm going to use a kinder method. Simply spray them with soapy water. It won't kill them, but it does get in their eyes. Naturally they will try and rub their eyes, and when they lift their legs to do so, they fall off the plant...

5 comments:

Jeaux said...

I believe ladybugs enjoy them too... for lunch. And they're even cuter.

Nyssa said...

I think the ants are very smart. When the Aphid falls off the plant what happens to it then? Won't it starve or just climb back on the plant once its washed the soap out of it's eyes?

barkfoot said...

Nyssa- I was hoping that they would give up and go onto nextdoors roses instead...

Madwag said...

cool stuff.... I love watching them in our garden

Lavender said...

Great post packed with tasty info, like a reqular encyclopedia article BRAVO Barkfoot! So far Im lucky that the Blue Wrens have been joined by the Thornbills, so I dont have many left to despatch manually - but I will remember the soapy water trick - much nicer than mashing by hand, Cheers!