Stage of life of an exuvia?

General
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https://www.inaturalist.org/observations/295926252
I found the shell of a cicada on the corner post of a back porch. Should the stage of life be annotated as (last-instar) nymph or adult?

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Since it underwent its final molt, it would either be a teneral or an adult (imago), depending on how long ago it molted. We can’t know if the cicada has now fully matured into an imago or is still a teneral and so I would leave it blank.

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Personally I annotate them as nymphs because the exuvia shows the body shape and characteristics of a nymph. Nymphs usually have less observations than adults, especially in Odonates, so by annotating the exuvia as nymphs it means the photos will show up when people filter for photos of nymphs.

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Hi, this is a very good question. As far as I know there is no guideline on how to annotate this, I personally use ‘molt’ for cicada exuviae.
I only use the life stage ‘nymph’ when the nymph is alive and hasn’t molted yet.
I differentiate between the two because there is a difference between a simple exuvia and a nymph, especially nymphs might have some extra colors which are not always on the exuviae after molting (e.g. nymphs might have black spots under the pronotum which are not present on the exuviae).

Hope this helps a bit :)

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Nymph records are useful because they show the habitat where it developed, whereas adults could have travelled. On the other hand, the date you saw the exuvia may be some time after the nymph emerged, so that could give a misleading date for when nymphs can be found. In other words, I don’t know. Molt sounds a good option if its definition fits.

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There isn’t an annotation value for life stage that fits this, IMO. Best to not annotate at all because we currently don’t know what life stage the organism is at, or if it’s even still alive, or how old the molt is. All we know is that it’s evidence that the cicada was there in the past and molted there. Annotating it as a nymph might create phenological data that is not correct.

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In my experiences, cicada exuviae seem to weather much better than odonate exuviae, so they persist in nature much longer and I see what you’re saying about the phenological data. However, my experiences with odonate exuviae is that they are much finer and more susceptible to break down quickly. They usually don’t persist in nature past the first rain after the odonate ecloses. I typically annotate mine as “nymph” and “molt” specifically for projects that gather observations of nymphal Odonata. Unlike cicadas (to my knowledge), the exuviae of odonates is extremely helpful in providing substantiated breeding sites and can often be identified to genus or species with basic photos. Projects that gather photos of nymphs and exuviae (annotated as nymphs) are crucial to understanding more about odonate morphology.

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