Comments on: Return of the supersoldier ants

By: Michael Habib

Michael Habib — Fri, 06 Jan 2012 21:54:48 +0000

That is an intriguing additional morphological difference. My first inclination would be to expect that the expanded wing discs are a side effect of the developmental changes, as you noted, but if there is a functional impact as Abouheif suspects, then the first that comes to mind is strain alteration in the thorax as a result of heavy reaction forces from carrying/using the hypertrophied head. The test for that effect would actually be highly tractable, and probably a few days work after getting surface scan data. I shall have to go ponder that… Thank you for writing back!

By: Ed Yong

Ed Yong — Fri, 06 Jan 2012 19:47:24 +0000

Alex can answer the allometry question better than I, but I’ll note that there is one more difference between the soldiers and the supersoldiers. The soldiers have a pair of vestigial wing discs (the bits that would normally develop into wings in other insects). They’re just these little nubs on its back. In the supersoldiers, there are two pairs of these and they’re bigger. They’re a bit odd and Abouheif has a hunch that they have some sort of function, but he doesn’t know what. Or they could just be a side effect of the general development programme that builds the supersoldiers.

By: Michael Habib

Michael Habib — Fri, 06 Jan 2012 18:43:59 +0000

An exciting and wonderful read; thank you Ed.

Alex: very excited to see you chiming in. I was curious about two items that you might be able to answer: 1) Are the supermajor forms in Pheidole an isometric blow-up of the major caste, or are there additional measurable differences in shape? 2) If there is allometry involved in #1, then are the major caste individuals in Pheidole fimbriata also similar in shape to the supermajor forms in other Pheidole taxa?

By: Alex Wild

Alex Wild — Fri, 06 Jan 2012 18:21:08 +0000

Thanks for reporting so calmly and thoughtfully on this one, Ed. Your pieces are always a pleasure to read!

This story has potential to get more interesting. Rajakumar et al did not include what Moreau inferred as the sister to the rest of the genus: Pheidole fimbriata. (Presumably because that’s a South American species that’s harder to collect). This species is dimorphic, like most Pheidole, yet the major is enormous. It looks like a supermajor, yet the species lacks a regular major caste.

By: Benoit Bruneau

Benoit Bruneau — Fri, 06 Jan 2012 14:43:20 +0000

I, for one, welcome our new insect overlords. Really interesting set of pieces (this one and Nature’s).