I'm pretty sure there is more than one species under the name "tapinoma sessile" here in canada as well. I have seen colonies that have larger workers and larger queens and are strictly monogynous, as opposed to the small polygynous ones.

During the last glacial maximum it is probable that no ants were present in your location unless there was a refugia population and that what you would have are populations that have reintroduced themselves during the past 8-10kyears.  The upshot is these populations are usually genetically very similar due to bottleneck scenarios.  My personal COX1 gene analysis for Canadian T. sessile has them all within one clade or haplotype, with more limited genetic diversity than the populations we have here in East Tennessee which did not undergo major glaciation. I would agree that there may very well be other "species" within the T.sessile population and crypsis is occurring. I also believe this species has been just "dumped" into a species bucket the default being:  It is a Dolichoderid, it is concolor, it has an odor = T. sessile.  South America has at least 6-7 recognized species and US/Canada/Mexico excluding the Caribbean with 2. It is known that tropical ecosystems foster greater speciation events and hence greater species.  North America is large though and it would not be surprising that what we know as T.sessile is actually a group of species.  I have a fundamental question though is how has speciation occurred in North America since opportunities for population isolation to occur do not readily avail themselves particularly in the Eastern half of the continent.  So I am quite curious how this novel species occurred. As for the Rocky Mountains being acting as a barrier, the ants I have acquired from Washington State clearly are T. sessile though they do have a lineage that is second oldest to the Tapinoma sp.nov.  that I am currently working on.  Current estimates of its population divergence have it in the mid to late Miocene then a 2-3 million year gap with the Washington State samples. Just keep in mind this is all inferred and tentative.

 

Interesting...

Edited by PurdueEntomology, December 9 2020 - 2:13 AM.

Where it all happens!

Nope no difference at all. No, really though those are excellent images and very informative.

Are there any morphological differences between workers too, or are males needed to distinguish between the two species?

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Yes.  There are currently 3  principle diagnostically significant morphological variations.  Once I get all my measurements and statistical analysis done there may be more.  

That's a pretty sizable difference on the ocelli! 

Here it is May 2021!  I was able to get to California this past weekend to collect samples of Tapinoma schreiberi along with reproductives of T. sessile which I did not have from the western population.  The morphological data so far has it very similar to my possible new Tennessee Tapinoma species.  I am just getting my SNP (single nucleotide polymorphism) work done to do a population structure analysis and that will be the clincher with regards to the new species thesis.  I did finish an analysis of the effects of climate and elevation on adaptive convergence with the East Tennessee Tapinoma sessile population and that seems to indicate that individual clades (sub populations) are positively adapting into niche environments based on elevation and precipitation.  I will be getting my first official draft of my thesis out by June 11 and hopefully defending in July with Master's being complete by August.  

This is extremely interesting!  Can't wait to see the thesis come out!  A little off topic kinda, but I have a friend who's last name is Perdue lol

 

Are there any morphological differences between workers too, or are males needed to distinguish between the two species?

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Yes.  There are currently 3  principle diagnostically significant morphological variations.  Once I get all my measurements and statistical analysis done there may be more.  

 

Excellent news, can't wait for the final results.

Edited by madbiologist, May 4 2021 - 4:28 PM.

We just assembled the whole genome of T. sessile from a male, meaning it is haploid.  One of the papers we wish to publish on our research is the whole genome of T. sessile which to our knowledge will be the first whole genome sequencing of this species.  We are looking into reconstructing the whole mitochondrial COX1 gene and see what it produces in a phylogenetic study.  Still waiting for the single nucleotide polymorphism (SNP) sequences to arrive to do the more detailed population structure.  So excited!!

Amazing work! Now you need to figure out how to keep them out of my kitchen!

just bait them.   my professor is looking into if after a colony has been baited if surviving pupae are able to eclose without assistance from nurse ants.  Though a colony may be affectively dead i.e., if reproductives are dead but that does not mean a residual colony may persist for a time and be a nuisance.  My mom has a huge polygamous colony at her house and around the yard.  She hates those [censored]-ants getting into her cookies!!  I was up there last Friday and actually observed intranatal mating i.e. siblings mating within the nest.  I had read it occur but never observed it myself. 

Got the single-nucleotide polymorphism (SNP) data back and will begin to compare each sampled ant to the reconstructed genome of our haploid male.  This will allow us to see genetic variation from our ant samples and thus establish relationships with our sampled ants with regards to population clusters, inbreeding, hybridization etc.  I will also be using this genome wide approach to construct a phylogenetic tree that is much more accurate than a single gene or suite of genes could do.  

Here is a link where this type of SNP data was used to understand invasive fire ants:                 https://link.springe...2862-019-1437-9  

Here is a link describing SNP's:                                                                                                      https://en.wikipedia...de_polymorphism

Unrelated, but I have seen 3 or 4 morphologically distinct species of Tapinoma (in size, behaviour) distinguishable from the queens here in Ontario

Amazing work! Now you need to figure out how to keep them out of my kitchen!