Strange Pairing

[jwa121]

A British Columbia lepidopterist on vacation in the interior of the province set up a light trap July 2nd and upon checking it in the morning found something unexpected.

He found a female Paonias myops (a small species of hawk moth) paired with a male of the very much larger hawk moth species Pachysphinx modesta.

A strange pairing indeed.

[boghaunter1]

Hi jwa121,

I find a few strange pairings like these almost every season in my light traps. I have found 3 such pairings already (different spp.) this season alone. Your example is very interesting due to the huge difference in size between those 2 spp.. Also was this a male to female pairing? Many times these are male to male pairings & I believe these are caused by the very close proximity/extreme crowding often found in the very small collection pail, box, etc. I have never observed this on collecting sheets or in the wild. Hybrids do certainly occur (very, very rarely) between closely related genera, but I have never seen a wild hybrid between any Sphingid spp. here in Sask....but that doesn't mean that they can't ever occur! Like Jeff Goldblum says in one of the Jurassic Park movies, "Life will find a way." Thanks for posting.

John K.

[jwa121]

Thanks very much for your reply, John.

In answer to your question, yes, this was a male-to-female pairing. A large, male, Pachysphinx modesta was found paired with a small, female, Paonias myops.

John

[adamcotton]

Apart from the issue of genetic incompatibility, it is highly likely that no larvae would hatch from eggs laid as a result of this pairing. The small female Paonias myops presumably has smaller sized eggs than Pachysphinx modesta.

Any larvae that develop inside these smaller eggs would be genetically coded for a head capsule larger than the egg, and as a result could not develop and hatch. If the pairing was the other way round there would be a higher chance of larvae actually hatching. However, if the eggs of the smaller species are actually larger than those of the large species the larvae could develop and hatch.

So, if anyone wants to make hybrids always use the species with larger eggs as the female in a pairing.

Adam.