Transformation

posted in: Bugs, Invertebrates, My garden, Worcestershire | 0

When I walked around the garden this morning, looking for insects, I was surprised to find that the weather had suddenly turned autumnal – dark, windy, and none too warm. I found a few invertebrates, but none that really interested me until I spotted two Red-legged Shieldbug (or Forest Bug) nymphs, huddling together as if for warmth in the curl of an apple tree leaf. For about the next quarter of an hour I tried to get some usable photos of them, but at that stage I was still struggling with the focusing system of the R7, and most of the files went in the trash almost immediately after upload. The camera was fairly lucky not to follow them.

Fast forward about four hours, during which time I took a restorative  lunchtime nap, and then worked through several videos on YouTube in which wildlife photographers shared their recommendations for setting up the menus, dials and buttons of the R7. Photographer and camera both now refreshed, back out into the garden we went, to try again.

I headed straight for the nymphs, and discovered that during my absence one of them had moved around to the back of the leaf (where you can see the silhouette of its exuvia) and undergone its final moult. On the one hand I was sad to have missed this transformation, but on the other I was able to get some images I think are quite interesting, in showing the difference between a final instar nymph and an adult. Even though I’ve seen many damselflies and dragonflies eclose, and I know that in Odonata the change in size and shape from nymph to adult can be startling, I still find myself looking at this photo in slight wonderment, and struggling to imagine the process by which the teneral shieldbug inflated itself, so as to achieve its adult profile before its new cuticle hardened.

The adult here is still quite pale, but as it matures it will darken to a deep brown colour, with a bronzy metallic sheen. The nymph must surely be due to undergo its own final moult very soon, and you can be sure that I’ll be checking on it first thing tomorrow, in the hope of catching it in the act. By the way, I learned a new word today, in reading around the subject of invertebrate moulting: this Wikipedia article on ecdysis is quite interesting on the stages of the process, and contains an excellent short, speeded-up film – almost more of a GIF, really – showing the final moult, or ecdysis, of a cicada.

In other news (and unsurprisingly, I guess, since this photo is in focus), the R7 is now behaving much better. I doubt I’ll ever love it the way I love the R5, but I think in time we may learn to get along tolerably well. I wanted a second, smaller camera body to use for macro work, as well as to provide backup for the R5, in the same way as I used to use my 7DII alongside the 5DIV – and it’s already obvious that the R7 is a much better camera than the 7DII, so to that extent at least, I’m satisfied.