Some aphids (especially the ones that don't undergo winter and lack the need of an egg phase) lack males and the ability to produce males and eggs altogether. I believe our Canadian ones are the egg and male bearing ones.
How do they produce males? Aphids are able to do it becase of a XO sex program. Aphids with XX turn into females and ones with XO turn into males. When males are needed, a semi meiosis happens. Here, one of the X is destroyed in the oogenesis phase to produce a XO and therefor a male. I don't really know how to discribe it any better, so someone else is welcome to jump in
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If you are wondering how they produce the genes to produce wings, that is beond me, lol. My guess is that they all have undeveloped wings, but they only fully grow when enviroment suits them (overcrowding, stavation, etc). Think of it as accidentally spilling fertilzer over a nep. The nep will develop leaves without traps, like a aphid with wings. When the fertilizer is washed out or used up, the need for traps is provoked and all those undeveloped buds will start to grow. That about the wings is totally a guess, so I am interested if anyone can explain it.
Aphids arn't that small, like a small ant at about 1-2mm, and is surely catchable. I guess they just stay on the stalks of the droseras, smart little buggers
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If your keeping your plants outside, they will return after you get rid of them
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Green thumb? I've killed more than my fair share of plants! I am more guilty than my plants
. Hope your aphid problems are solved. Zongyi