Tuesday, May 7, 2013


Yesterday I posted some pictures of the ichneumon wasp called Orthopelma mediator that parasitises Diplolepis rosae, the gall wasp that causes bedeguar galls on wild roses. Today seven more parasites hatched out, but so did two surviving D. rosae gall wasps, pictured below. Large galls, like the one I collected, can contain up to 60 D. rosae larvae.

These dumpy little wasps, about 4mm. long, have a very distinctive profile with an enlarged red abdomen that's keeled underneath.

Almost all D.rosae individuals are female and reproduce parthenogenetically, producing fertile eggs without fertilisation by males, which are rare. The female inserts her eggs in rose leaf buds just before they begin to open and the plant cells that they are attached to proliferate to produce the spectacular mossy, crimson gall, which contains a nutritive tissue that the larvae feed on.

Below are a couple of pictures of the gall produced by this little wasp


  1. Amazing stuff Phil. Our world and nature never cease to amaze me. I'm so glad you share your knowledge.
    If only more schools taught about nature in this way, I'm sure it would be a better place.

  2. Hi Keith, I originally set up this blog because part of my job when I worked at Durham University was to develop resources for schools. It was the kind of stuff that fascinated me when I was growing up - and provided me with a career - so I sort of hope that it might do the same for some of the next generation...