Diario del proyecto 2024 Magicicada: Broods XIII and XIX

More and more adult Magicicada are emerging in the northern part of Brood XIX's distribution, and along with them comes the difficulty of identifying the two decim species in the brood: M. tredecim and M. neotredecim. While it's true that M. neotredecim is more closely related to septendecim and tends to be darker, variation is present in all three decim species. I've seen septendecim in previous emergences that were nearly devoid of black on the underside of the abdomen, and I've also seen surprisingly dark tredecim (in areas where only tredecim is present).

M. neotredecim is no exception; it also varies and can be a bit lighter or darker than is typical. John Cooley, who along with Dave Marshall originally described the species, noted that a population in central Illinois is atypically light: see his description of the 3D model here: https://cicadas.uconn.edu/m_neotredecim/

This is why I'm doubtful that coloration alone is a good enough feature for species ID, and why I'll continue to stick with complex-level (more accurately, species group) IDs in areas where both species are possible. As a rule of thumb, reliable genus-level records are more valuable than questionable species-level ones.

Sound recordings, on the other hand, have the potential to be very useful; high-pitched, "displaced" calls occur in areas where neotredecim and tredecim overlap. (See https://cicadas.uconn.edu/rcd/) It would be great to build a good collection of these on iNaturalist!

Temperatures are climbing, and the southeastern woods are ringing with loud cicada choruses! More observations are coming in of holes and nymphs in Brood XIII territory, so they're not far behind their southern cousins. Keep an eye out for the black patches on northern nymphs, which will appear just before they're ready to emerge and undergo their final molt.

In light of all the records coming in, I've broadened the project parameters to include "Needs ID" observations. I hope this will reduce the pressure on identifiers and relieve frustration for contributors who have submitted observations that aren't appearing in the project. It's easy to see just the RG observations by ticking one box in the filter panel, so let's welcome all Magicicada observations to the party!

Misidentifications of Magicicada are relatively uncommon, and usually consist of annual cicada skins or nymphs (which will have a broader, rounder thorax and are often greenish), CV misidentifications of species like Okanagana and Platypedia (which can typically be filtered out by range), and the occasional bee fly pupa, a.k.a. "sky shrimp" (go figure!).

As more adults emerge, remember that (at least for species ID purposes), underside photos of fully darkened adults are everything!

Spring has officially sprung, and adults have begun to emerge in the southeastern US! Three species (tredecim, tredecassini, and tredecula) have been confirmed from SC and GA, so remember to get those all-important shots of the underside of adult, fully sclerotized cicadas if you’re keen on species ID. Check out cicadas.uconn.edu/species for more info on the key characters, and to hear recordings of calls. (A few calls have already been reported on Cicada Safari!)

I’m currently traveling in northern Greece (checking in from the very pretty mountain town of Metsovo at the moment), so my apologies if I’m slow in answering questions or messages. It’s not easy to iNat from a tiny phone screen 😅