PhD week 51: Corbels

A selection of corbels. For larger pictures and my interpretation of the structures, see the examples on my Flickr page.

The corbel is a character on the hind leg that is frequently used in the higher classification of broad-nosed weevils. It is a feature that is difficult to describe in words, and can be tricky to see at first. Unfortunately, there are few easily accessable pictures that show the different types of corbel. This post is an attempt to rectify the situation.

The corbel refers to the form of the apex of the hind tibia. An "Open" corbel has no particular modification to the apex. An "Enclosed" or "Closed" corbel has a flat area (often with scales or short setae) lying between two rows of setae on the outer edge of the tibial apex. When the corbel is large, such as in Leptopius and Cecyropa, it is easily seen. However, sometimes the corbel can be very slender, as shown by Naupactus leucoloma. In such casees, it can be difficult to determine whether the corbel is open or enclosed. A "Semi-enclosed" corbel has a concave area between the apex of the tibia and the insertion of the tarsus that is always bare. It is important to note that the semi-enclosed corbel is not homologous with the enclosed corbel.

An excellent discussion on the corbel, that goes into a lot more depth than I've covered here, can be found on the International Weevil Community Website.

References:
Thompson RT. 1992. Observations on the morphology and classification of weevils (Coleoptera, Curculionidae) with a key to major groups. Journal of Natural History 26: 835–891.

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Read:
   Ferngren GB (Editor). 2002. Science and Religion. A Historical Introduction Baltimore: The John Hopkins University Press
   Hughes P (Translator). 1937. Meditations for Lent from St. Thomas Aquinas. London: Sheed and Ward
    St Augustine, Betteson H (Translator). 2003. City of God. London: Penguin Classics
   Proverbs 13–16

Watched:
Star Trek: Enterprise Season Two
National Geographic—Best videos of the Russian meteor strike

PhD week 50: Thomas Broun

Portrait of Thomas Broun. From Searell P, Watt JC. 1974. Science gallery: Thomas Broun (1838–1919). New Zealand's Natural Heritage. 3(37) via Bugz

The key figure in the study of New Zealand beetles is without a doubt Thomas Broun (1838–1919). Born in Scotland, he served in the British Army, seeing action in the Crimean War and the Indian Rebellion. He arrived in New Zealand in 1863, where he served in the New Zealand wars before becoming a school teacher on retirement from the army. While he had a strong interest in natural history from a young age, it was not until his arrival in New Zealand he began serious taxonomic research, describing insects in the evenings after work. Over the course of his 56 years in New Zealand, he described 3538 beetle species, covering all families.

While his work has not, in the words of Elwood Zimmerman "stood the test of time", it must be remembered that it was done in testing conditions and with the aid of substantially poorer optics than we have today. Being so distant from the centre of entomological research at the time, he had to rely on the literature he was able to obtain from European colleagues. His decision to bequeath his collection to the British Museum of Natural History has indeed limited further research into New Zealand beetles; but this decision was a prudent one in an age where New Zealand institutions were still very much in their infancy.

He described approximately 70 species of Irenimus, though he described them in the genus Catoptes. He recognised the difficulty of the group, and made the following comment in 1904:

[Catoptes (= Irenimus) duplex] is one of several species that do not accord exactly with Catoptes, Brachyolus or Inophloeus, but partake more or less the structure and appearence of all three. In order to avoid confusion it will be necessary before long to redescribe these genera and define their limits more accurately; when that is accomplished the aberrant species alluded to above may be referred to new but certainly very intermediate genera. As I have not seen some of these species as yet, and as very few examples of some others are possessed by me, the difficult task must be allowed to stand over at present

This "difficult task" has been left until now. Here's hoping that my contribution will finally make this group tractable.

References:
Crosby TK. 2012. 'Broun, Thomas - Broun, Thomas', from the Dictionary of New Zealand Biography. Te Ara—the Encyclopedia of New Zealand
Cheesman TF. 1920. Major Thomas Broun 1838–1919. Transactions and Proceedings of the New Zealand Institute 52: ix–x

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Read:
   Ferngren GB (Editor). 2002. Science and Religion. A Historical Introduction Baltimore: The John Hopkins University Press
   Hughes P (Translator). 1937. Meditations for Lent from St. Thomas Aquinas. London: Sheed and Ward

Websites:
The Internet Bird Collection—Videos, photos and recordings of a number of birds around the world

Watched:
Project 86—Fall, Goliath, Fall music video
Open AIr Summer Shakespeare 2013—Twelfth Night
Star Trek: Enterprise Season Two

PhD week 49: Slide mounting

Weevils slide mounted in Euparal

If you look back over previous blogposts (such as this one and this one), you'll see that I've agonised over different microscope mounting media like I were a character from Twilight. Swayed by my colleague, Rich Leschen, I have thrown my lot in with Euparal, and have spent the past week dissecting and slide-mounting weevil specimens. I will be unable to see the results for another two weeks or so, but initial indications suggest that it will have been a worthwhile exercise. The features that I particularly hope to see are characters of the mouthparts, where I hope to see differences between species that suggest different food preferences. Determining these differences will require careful observation, and it is hoped that these slide mounts will make the task much easier.

While it seems that I am currently at peace with my decision of slide mountant, there remain some dark clouds on the horizon. I recently read a paper that states that Euparal is becoming difficult to source due to a combination of concerns over its toxicity, and its continued availability. This paper suggests dimethyl hydantoin formaldehyde (DMHF) or polyvinylpyrrolidone homopolymer (PVP) as possible substitutes. Maybe my slide mountant angst will continue for a little while yet.

References:
Leschen RAB. 2005. Erotylidae phylogeny and review (Insecta: Coleoptera: Cucujoidea). Fauna of New Zealand 47: 1–108
Liberti G. 2005. Improved solutions of two water-soluble media for mounting beetle genitalia. The Coleopterist 14(1): 29–35.

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Read:
   McCulloch D. 2010. A History of Christianity: The First Three Thousand Years London: Penguin

Websites:
DNA barcoding blog—Seven Deadly sins of DNA barcoding
Tom Robinson—Māori Macron Characters

Listened:
Angel D'Agostino—Adios Arrabel

PhD week 48: Alpine collecting

Camping at Round Hill Skifield.

I love skifields. Only at this time of year though. In a few months time they get covered with snow, and all the insects hide away making them not worth visiting in the slightest. In the past week, I had two very pleasant days in the Two Thumb Range at Round Hill and Mt Dobson Skifields. The point of the trip was to search for Haplolobus saevus, which was collected from the "mountains near Lake Tekapo" according to the original description. We managed to track some down in some spent flowers of Celmisia lyalli at Round Hill. We also found some specimens of Inophloeus in Aciphylla plants growing at the top of Mt Dobson skifield at an elevation of 1950 m. Pretty hardy organisms! The weather was perfect, the company was enjoyable, and the collecting was excellent. The total was one very succcessful field trip.

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Read:
   Chesterton GK. 1908. Orthodoxy. Image, New York (2001 Edition)
   McCulloch D. 2010. A History of Christianity: The First Three Thousand Years London: Penguin

Listened:
Phantom Empire—If the World Burns
Blindside—The Great Depression
Norma Jean—Meridonal

Watched:
Star Trek: Enterprise Season One