Avarua, Cook Islands
Identification request
2021-07-11T23:35:43.3477525Z
   2
Melittobia sp. Rarotonga

Kia orana Hymenopterists,

We would be most appreciative if these putative Melittobia could be identified to species. They were found in a leaf-cutter bee nest, Megachile nr. laticeps.

I have not found references to any Melittobia in nearby countries such as Fiji, Samoa, Tonga or French Polynesia.

Regards, Gerald

Hymenoptera

Responses

   0
2021-08-10T14:00:00.0000000Z

Hi Gerald

It's taken a while but we are able to answer your question, or at least get close. I just have to get some permissions, and then will let you know. This is to whet your appetite with some references! I must say that a lot of people have been interested in Melittobia since your post, and also very taken by the excellence of your images. I rue the fact that I could not get funds for you to show the region how you do it. Perhaps training via Zoom would be a possibility.

An associate has sent the following:

Dahms EC. 1984. Revision of the genus Melittobia (Chalcidoidea : Eulophidae) with the description of seven new species. Memoirs of the Queensland Museum 21, 271-336.

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2021-08-10T18:00:00.0000000Z

Hi Gerald 

I am pleased to tell you that Dr Chris Burwell, Senior Curator, (Entomology), Queensland Museum, has looked at your images. This is what he has to say:

I’ve had a look at those images of the Melittobia species from the Cook Islands, they are amazing images given the minute size of the wasps.

One the previous curators of entomology at the Queensland Museum was Ted Dahms who revised the world species of Melittoba, so we have specimens of a number of species in the collection.

I’ve had a look though Ted’s revision of the genus (Dahms, E.C.D. 1984. Revision of the genus Melittobia (Chalcidoidea: Eulophidae) with the description of seven new species. Memoirs of the Queensland Museum 21(2): 271-336) and the antennae of the male from the Cook Islands most closely resembles that of two described species, M. australica and M. hawaiiensis. Males of those two species are extremely similar to each other and Dahms’ distinguished them on the basis of the number of setae on part of the underside of the first segment of the antenna, while the females couldn’t be distinguished. Unfortunately the underside of the first segment of the antennae isn’t visible in the images, and even if it were, I don’t think there’s enough detail to distinguish the individual setae.

So the best I can suggest is that they are either M. australicaM. hawaiiensis or perhaps an undescribed species.

END

Gerald, I can given you Chris' email if you wish.

grahame

2021-08-13T21:57:40.0779477Z
Many thanks Grahame for your persistence and many thanks Chris for your extensive expert support. I am traveling at the moment and will follow up in a couple of weeks when I get back to the office. Remarkable that you have it down to one of two species ("or perhaps an unsubscribed species"). Great to know that M. australica and M. hawaiiensis have a distinctive separating feature. I'll see what I have in images, but, in particular, I'll investigate the male antennae more thoroughly on the next specimen. I'm glad you enjoyed the images. Live images with Olympus TG4 (point-n-shoot) and dead images with fairly cheap digital camera on trinocular microscope (?40x). Then Photoshop cropping, resizing, Levels and Smart Sharpening and saving a jpg Quality 12. In this case the 4 inserted images were sized to 450x300px to fit into our standardized 900x600px. Our main secret is the standardized overall size, Levels and Smart Sharpen which saves the time of wondering what else you could manipulate. Meitaki ma'ata, Gerald