Forum Entomologi Italiani
http://www.entomologiitaliani.net/public/forum/phpBB3/

Onthophagus taurus (Schreber, 1759) - Scarabeidae
http://www.entomologiitaliani.net/public/forum/phpBB3/viewtopic.php?f=170&t=32547
Pagina 1 di 1

Autore:  Lenny [ 29/03/2012, 23:00 ]
Oggetto del messaggio:  Onthophagus taurus (Schreber, 1759) - Scarabeidae

Hello together
i wish you all a succesfull insect season! 8-)

At first i have this Onthophagus from the Bosnian mountain Romanija which is about 1400m high.
Size is 8.5 mm

Can someone determine?

Ciao :)

P1210997.JPG


P1220016.JPG


P1220027.JPG


Autore:  cosmln [ 29/03/2012, 23:50 ]
Oggetto del messaggio:  Re: Onthophagus from Bosnia

:?: :?: Onthophagus taurus (Schreber, 1759) :?: :?:

Autore:  Creedence [ 30/03/2012, 8:11 ]
Oggetto del messaggio:  Re: Onthophagus from Bosnia

D'accordo con Cosmin: un maschio di O. taurus.

Autore:  Lenny [ 30/03/2012, 17:57 ]
Oggetto del messaggio:  Re: Onthophagus taurus (Schreber, 1759) - Scarabeidae

Thank you !!
But if it's a male - where are his horns?? :cry:

Autore:  aphodius [ 30/03/2012, 19:02 ]
Oggetto del messaggio:  Re: Onthophagus taurus (Schreber, 1759) - Scarabeidae

Lenny ha scritto:
Thank you !!
But if it's a male - where are his horns?? :cry:

It's normal for hypotelic male. Only hypertelic males have long horns.

Autore:  Lenny [ 01/04/2012, 17:00 ]
Oggetto del messaggio:  Re: Onthophagus taurus (Schreber, 1759) - Scarabeidae

aphodius ha scritto:
Lenny ha scritto:
Thank you !!
But if it's a male - where are his horns?? :cry:

It's normal for hypotelic male. Only hypertelic males have long horns.


Does that mean it disguises itself as a female so it can sneak in the district of a horned male and "steal" the female?
Or is it just because of insufficient diet?

Ciao

Autore:  aphodius [ 01/04/2012, 22:21 ]
Oggetto del messaggio:  Re: Onthophagus taurus (Schreber, 1759) - Scarabeidae

See e.g. this link:

http://www.bio-nica.info/biblioteca/Jol ... ertely.pdf

Autore:  Lenny [ 02/04/2012, 18:41 ]
Oggetto del messaggio:  Re: Onthophagus taurus (Schreber, 1759) - Scarabeidae

Thank you for the interesting link, but my question is why this male has no horns and not how the horns developed. If males of the same species can have horns or no horns, this must either be a phenotypical variance of the species or a result of different food disposability (in both cases then there must be "intermediate forms"). Or are there only hypotelic and hypertelic males and no forms between them? Then my idea from above (camouflage) could be a possibility? :roll:

Sorry for annoying questioning. I'm just so curious. :gh:

Autore:  aphodius [ 02/04/2012, 19:26 ]
Oggetto del messaggio:  Re: Onthophagus taurus (Schreber, 1759) - Scarabeidae

So, it's interesting theme. Naturally, there are "intermediate forms". Generally, very small males have mostly no horns. On the other hand, very big males have mostly very long horns (but not always!). Medium-sized males have horns more or less reduced. Why? I'm afraid answer to this question will not be easy. Certainly it relates with sexual competition between males, not only with different nutritional conditions of larvae.

Autore:  aphodius [ 03/04/2012, 16:17 ]
Oggetto del messaggio:  Re: Onthophagus taurus (Schreber, 1759) - Scarabeidae

Hi Lenny, today I obtained paper dealing with this matter:

Allegati:
Moczek2000.pdf [216.82 KiB]
Scaricato 10 volte

Autore:  aphodius [ 03/04/2012, 16:20 ]
Oggetto del messaggio:  Re: Onthophagus taurus (Schreber, 1759) - Scarabeidae

And another one:

Allegati:
Moczek2010.pdf [774 KiB]
Scaricato 10 volte

Autore:  Lenny [ 03/04/2012, 22:38 ]
Oggetto del messaggio:  Re: Onthophagus taurus (Schreber, 1759) - Scarabeidae

These are very interesting informations! For me it's traceable now. Big males often have big horns and are more succesfull in fighting for the females. For smaller males it makes no sense to develop horns because they will always be weaker in fights with the bigger males. So they keep totally hornless and gain mobility and agility instead. Then they can sneak around and infiltrate the bigger males tunnels and mate with the females. It's an alternative reproduction strategy. (source: Moczek 2000)

I think the fact that there are few "intermediate forms" is just a genetic remain because the "horn-thing" will surely be older than the sneaking.
Thank you :)

Pagina 1 di 1 Tutti gli orari sono UTC + 1 ora [ ora legale ]
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/