Baileya multiradiata and Trigonorhinus fungus weevils

When collecting seeds of desert marigold (Baileya multiradiata for you latin fans) I more often than not run across fused clumps of seeds in the seedheads that have been partially eaten and abandoned leaving a chamber and frass behind. This week as I was gathering some I found larvae and later adult fungus weevils (Trigonorhinus) in those chambers. The best match looks to be Trigonorhinus griseus, but being out of my field I'm reluctant to call a species.

As noted the chambers are quite common. This morning I collected and dissected ten likely seedheads (well-dried and shedding old flowers), and found the following:

Larva 2
Pupa 0
Adult 5
Empty chamber 2
No chamber 1

Nine of the ten had chambers. Larvae and adults were alive and were returned to their hosts.

If you have access to plants with mature seedheads (see attached photos), I'd be interested in a count of ten looking for evidence of a chamber (some of the seeds firmly clumped). If you want to go further and open them looking for occupants all the better.

Posted on November 07, 2021 04:07 AM by stevejones stevejones

Observations

Photos / Sounds

Observer

stevejones

Date

November 3, 2021 10:25 AM MST

Description

Larval beetle in Baileya multiradiata seedhead. Adult of presumably the same beetle species here. Both found in mature seedheads.

Photos / Sounds

Observer

stevejones

Date

November 3, 2021 11:05 AM MST

Description

Adult beetle found in Baileya multiradiata seedhead. Larva of presumably the same beetle species here. Both found in mature seedheads.

Photos / Sounds

What

Desert Marigold (Baileya multiradiata)

Observer

stevejones

Date

November 6, 2021 10:16 AM MST

Description

Old flowerhead with flowers and seeds (two layers); Trigonorhinus fungus weevil below. Second photo shows old flowers, third the seeds below. Fungus weevil larvae and adults frequently found in chambers within Baileya seed layer.

Tags

Comments

Detailed observations like this, focused on most every native plant, are bound to pick up the many organisms that use or inhabit it. Its the great fun in observing again and again the same plants and other biota.

Posted by mjplagens over 2 years ago

Loved learning about this weevil! Excellent photos.. Thank you :-)

Posted by ezpixels over 2 years ago

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