Is it the grass that is dying, or is it heaps of soil from ants' nests?
By the way, it won't be dragonfly larvae as they lay their eggs in ponds. I expect your neighbour means cranefly larvae (known as leatherjackets) - they eat the roots of plants -
When you see starlings and crows probing into the turf on meadows and playing fields etc it's the cranefly larvae that they are looking for. It may be that this is a bad year for leatherjacket infestations as they like the ground to remain damp throughout the summer.
If it is leatherjackets it will be the grass itself that is yellowing and dying (not heaps of soil). If you have a bad infestation you can treat with nematodes vhttp://www.harrodhorticultural.com/nemasys-leatherjacket-killer-pid7625.html and it's cominng up to the right time of year to do it.
If it is ants making ant hills, then there are also nematodes to deal with them http://www.unwins.co.uk/nemasys-no-ants-pid2590.html
We've got red ants in our lawn, but as we've got green woodpeckers in the area I'm hoping that the ants will attract them to our garden and they will deal with them for us.