An Aphids sacrifice

GrayB · #1 (**permalink**) 31-05-2009, 05:48 PM

Hi Everyone,
I knew from photos online that hoverfly larvae fed on Aphids, so when i saw one approaching a group of Aphids i was almost sure what was going to happen but what i wasn't expecting was what actually happened.
In the first shot you can see that the larvae has grabbed the Aphid nymph but as it grabbed it the mother was away to the right of the shot and as soon as the nymph was grabbed she walked down towards the larvae and straight over it as if saying, take me.

And in the second shot you can see that the young nymph is safe to the right of the pic but the mother has taken the young nymphs place and i truly believe that she knew exactly what she was doing.
Or have i read it all wrong?

Will the insect world ever stop amazing me.
Gray.

Snowyriver777 · #2 (**permalink**) 31-05-2009, 06:03 PM

I aggree highly, nature, especially the insect group, always amazes me, and the point that this mother sacraficed herself is amazing, but also prooves how cruel nature is, thanks for sharing your experience.

Jason Green · #3 (**permalink**) 31-05-2009, 06:18 PM

As you say Grey, if this has been read correctly that is one of the most incredible insect occurences I've seen all year. Not least because aphids are often considered pests yet here they are sacrificing themselves!

Great find G, and nice to see you sticking around too, Snowy!

charlieb · #4 (**permalink**) 31-05-2009, 07:06 PM

I find it hard to believe that the mother would sacrifice herself for one nymph - she is capable of producing thousands more (and the nymph looks sucked dry already...) and is as defenseless. If she had some form of defense mechanism that would give her an advantage and chance of survival maybe (for example the Ringed Plover and "broken wing" act)

I think what you have seen is maybe a tactic of "everyone run", and it just so happened she ran into the jaws of the larva.

Jenny W · #5 (**permalink**) 31-05-2009, 07:19 PM

I have to agree with charlieb I'm afraid - they are aphids after all.

GrayB · #6 (**permalink**) 31-05-2009, 08:05 PM

Well it was only my interpretation of what i saw, i'm no expert on aphids and i appreciate everyones point of view, so thanks for the comments but i don't think anyone will no for sure.
Gray.

Paul mabbott · #7 (**permalink**) 01-06-2009, 09:12 AM

Yes, the first aphid was long dead.
However, we shouldn't, in principle, assume that aphids or other insects are incapable of altruistic behaviour. It's a question of numbers - in this case there would be no value in a sacrifice but in other cases (amongst Hymenoptera most notably) one or two animals will often sacrifice themselves in defence of the greater population.
It does happen in one species of aphid:
BBC NEWS | Science & Environment | Aphids' sticky suicide missions

jaguarondi · #8 (**permalink**) 01-06-2009, 09:13 AM

Again I'm no expert, but I think when aphids are alarmed they exude a pheromone which can excite others in the colony. I've seen this happen with black bean aphids - give one a prod then the whole colony start waggling their bottoms and shifting position. I wonder if the nymph exuded this pheromone and that panicked the mother into fleeing - unfortunately in the wrong direction.

squishy · #9 (**permalink**) 01-06-2009, 09:54 AM

excellent photos.

GrayB · #10 (**permalink**) 01-06-2009, 09:11 PM

Paul,
Thanks for the link it made a very interesting read and it does show that there can be alot more to the average aphid.
After reading through this post i'm going to have to admit that the chances are i probably saw what i wanted to see and didn't truly think other possibilities through, and i do think jaguarondi's theory is probably closer to the mark.
It's been a very informative post for me

Snowyriver, Jason, Charlieb, Jenny w, Paul, jaguarondi and Adam thanks for all of your views on this.
Gray.