This is a follow-up to previous sighting 4573397 and MarkT’s sighting 4571518 to try and identify the type of insect. It appears to be similar in size, shape and colouring to a Giant Snowball Mealybug (Monophlebulus sp.). I thought that additional images and details of the insect and particularly its underside, might help with identifying it. The additional images shown in this sighting haven’t helped me with identification, but they have established that the insect was dead and have determined the cause.
The first image in this sighting was taken a few days ago and comparison with MarkT’s sighting shows the insect hasn’t moved for several weeks. The insect appears to have twelve dark cylindrical shaped markings on the orange background of its upper surface. The second image was taken with light shining through the insect’s body from underneath and this shows that the dark markings are not on the upper surface but are shapes within the insect’s body.
The third image shows the insect turned over, exposing its underside and explaining what has happened to it. The insides of the body and the complete underside have been eaten away. There are twelve dark coloured, pupae cases within the insect’s body. These are all facing inwards towards the centreline of the insect’s body. The pupae cases contained twelve adult parasitic wasps, some of which are shown in following sighting 4575452 just after they hatched. The third and fourth images show 5X magnification of some of the empty pupae cases after hatching, with the fifth image being at the host insect’s head end.
It appears that the insect has been parasitized by a female parasitic wasp, one capable of laying multiple (rather than single) eggs within the host insect. The eggs have hatched, and the larvae have fed on the host insect, eventually killing it. The wasp larvae within the host insect have then formed cylindrical shaped pupae. Because of the very thin layer of remaining host covering the pupae, they appear as twelve dark coloured surface markings.
The adult wasps emerged from the pupae all at the same time on June 7th, three weeks after MarkT’s original sighting.
I still don’t know what the host insect was but this sighting and the following one showing the emerged adult wasps (4575452) may help CNM’s moderators with identification.
Great observation @TimL . The shape is wrong for a *Monophlebulus* and I'm not convinced it's a scale insect. It looks familiar but I can't remember where I've seen it before. If/when I do I'll come back and update.