What we know so far!

Hi Everyone,

Just checking in with an update, and what is going to be happening going forward! It's been about a year since my last update. Since I posted that lab note, another whole field season went by, and I got to collect more samples! I also got some interesting results, and have some new plans for how to proceed.

Let's first start with results! In my last note, I wanted to make a phylogeny of these organisms to see where things stand, well... here we go!

 

Maximum Likelihood Tree of Mitochondrial DNA (COI gene) of Sphinx gordius, S. poecila, S. oslari, S. luscitiosa, and two outgroups, C. undulosa and S. drupiferarum

This is the first pass at a tree for this species group. As you can see, it's ***COMPLCATED***. Essentially though, there is a difference in the barcodes between Sphinx gordius and Sphinx poecila. This means that according to the COI gene metric, they are separate species. Is this the end-all-be-all? No! There are a lot of other strange factors.

The natural follow-up to these results for me was dissection of the male genitalia. This is to see what they (S. gordius and S. poecila) looked like, and to note any differences. Well... they're the same!

 

Images of the male genitalia of the Sphinx group

This is interesting, because typically we expect differences in dissimilar species. For example, even in the closely related Sphinx luscitiosa has differences that are rather clear. Sphinx drupiferarum looks very different as well. Of course, these are not the only specimens I dissected, but it is representative.

Coupling this data with how variable the moths and caterpillars are, it doesn't totally paint a very clear picture, and we are still back to square one with being able to differentiate the species visually. Let's take a look at this variability.

 

Adults of Sphinx gordius (left) and Sphinx poecila (right) verified by barcode of COI gene

These are adults verified by barcode. In the first batch of barcodes, there were only 4 S. gordius, compared to 20+ S. poecila. The images here represent the extreme variability found in this group of moths. We see this when we look at their larvae as well, these images are not IDed to species, but represent the variability well.

 

Larvae of the Sphinx gordius/poecila complex

Well, what does this all mean?

MORE WORK!

I will be repeating this process on more specimens to try and locate more S. gordius genotypes. This will help with morphological studies. I will also be taking the extracted DNA from all the specimens and look at different genes, this time in the nucleus to see if there are differences there or if they are similar.

Currently, the projected timeline of having a paper on this subject is sometime in April 2025. I know that seems like a long way away, but with the amount of work that still has to be done to be really thorough and the write-up, it's needed.

If you have any questions, please feel free to reach out to me!