Any experience breeding Tityus-Granti Hybrids?

[STELLAR]

I'm wondering if anyone has ever hybridized these Hercules beetles (or, frankly any other living thing)

 

I'm wondering if the hybrids were viable or sterile, and how many generations. 

 

I saw online that in a large group of hybrid females only one laid eggs making a second generation of hybrids.  I have no further info on how the second generation did.

[Goliathus]

I'm wondering if anyone has ever hybridized these Hercules beetles (or, frankly any other living thing)

Yes - hybrids have been produced between tityus & granti, hyllus & hercules, and (possibly) hyllus and granti.

I'm wondering if the hybrids were viable or sterile, and how many generations. 

Fertility results from hybrids are variable.  So long as two species are not separated by any more than about 2 million years of speciation, they should (theoretically) be able to hybridize.  However, whether or not the hybrids are fertile varies, and likely depends upon just how much genetic drift has occurred between the two species involved.  Of course, in the case of some insects such as beetles, the form of the reproductive organs between even species that are in the same genus can be different enough that successful mating between the two is unlikely to occur.

I saw online that in a large group of hybrid females only one laid eggs making a second generation of hybrids.  I have no further info on how the second generation did.

Yes - I assume you are talking about the following web page? - 

http://www.uky.edu/Ag/CritterFiles/casefile/insects/beetles/hercules/hybrids.htm

 

[STELLAR]

Yea I was talking about that web page!

So how many generations did your hybrids remain viable for?

[Goliathus]

I've never produced any Dynastes hybrids myself, although I've often had the opportunity to mix tityus and granti.  Many hobbyists are against producing hybrids, for fear of contaminating pure species bloodlines.  If hybrids are produced, one should definitely take care to keep them separated from any pure species lines.

[STELLAR]

I dunno, If i could perfect hybridization I could potentially "discover" a new type and have it named after me. I'd follow this breeding pattern formula.

What are the characteristics of a "Pure" Dynastes Tityus? I've observed D. Tityus larva with black face plates and reddish maroon face plates. Is one of these more of a "true" eastern? Or is this all just silly beetle racism?

 

T = Pure Tityus, G = Pure Granti, H = Hybrid

 

Gen 1: T + G = H

Gen 2: first group H + G = H and second group H + T = H

Gen 3: first H + T = H and second group H + G = G

Gen 4: First group H + Second group H then hopefully at that point they would be viable...

[Anacimas]

15 hours ago, Goliathus said:

...So long as two species are not separated by any more than about 2 million years of speciation, they should (theoretically) be able to hybridize...

 

How is this figure determined for particular species?

 

 

[Goliathus]

I believe that the "2 million years" quote is based upon research on a variety of species, (esp. mammals) though it might not necessarily apply to all animal groups (inc. insects), and probably not to plants at all.  Of course, through genetic engineering, it's possible to mix genes from species separated by hundreds of millions of years (e.g. cats and jellyfish).  Undoubtedly, we'll be seeing a LOT more of this in the years to come.

[Anacimas]

Well, when querying www.timetree.org to determine the phylogenetic distance between Dynastes granti and Dynastes tityus, I get an error message telling me the two taxa are the same. Guess this means I have to power up my trusty time machine again, carefully setting the dial for 2,000,000 years...

[Goliathus]

At the genus level, there won't be very much genetic difference between two species, even if their physical characteristics are quite different.  D. granti and D. tityus are very closely related, and by some classifications, they may simply be viewed as geographical races of the same species.  They possibly diverged from a common ancestor when increased aridity in the southwest geographically separated the AZ / NM mountains from the wetter environments of the east.

[Anacimas]

An interesting read in this regard is Jen-Pan Huang's "The great American biotic interchange and diversification history in Dynastes beetles" in the Sep 1 2016 issue of the Zoological Journal of the Linnean Society, wherein, among other strong assertions, granti and tityus are absolutely classed as separate and distinct species.

What's the point of all this?

I contend:

1. The 2 million year figure for granti/tityus bifurcation may well be accurate but could also be off by an order of magnitude or more.

2. Although taxonomy has come a long way in the last few centuries, a precise understanding of species and speciation remains frustratingly elusive.

3. Ultimately, Stellar's queries re hybrid viability can only be addressed via experiment.

 

 

 

 

[Goliathus]

I am in agreement with all of these comments.

Yes, it's quite possible that granti and tityus diverged considerably less than 2 mya.  They might not have appeared as distinct "species" until sometime well into the Pleistocene, possibly even the latter part of the epoch.