Posts Tagged ‘Coleoptera’

Insect Minute – What is the biggest insect?

Wednesday, July 18th, 2012

When you are in a specialized career, like entomology for example, you are bound to get many questions. Some of the common questions we get are “What is the most dangerous insect?” “Which has the worst sting?” or “Who would win in a fight between place two large insects that would never cross paths here?” We’ll save these questions for future Insect Minutes. The question that we seek to answer this week is, “What is the biggest insect?”

Aggggghhhh!! That is one big insect!!

To answer this question we need clarification, how do you quantify “biggest”? Insects are very diverse and they come in many shapes which means that the longest is not the heaviest.  So to answer the question of what is the “biggest” completely there are two answers.

The longest insect is the Chan’s Mega Stick from Borneo. Phobaeticus chani is a member of the stick-insect order Phasmatodea. Our native species, Diapheromera femorata, is 3 to 4 inches long. Phobaeticus chani is 14 inches long, if you include the legs the length extends to 22 inches!! Despite its large size very few people have seen one, in fact if you searched all the insect collections in the world you would only find that 3 have been collected. All stick insects are masters of camouflage living up to the order’s prefix which comes from the Greek, phasm, meaning phantom. It may be that the Chan’s megastick is even more elusive because they typically reside in canopy of the rainforest.

Phobaeticus chani, or 'Chan's megastick,' mounted and displayed.

Image from FoxNews.com

The aptly named Goliath beetle is arguably the heaviest insect, based on the bulk of the five beetles included in this genus. The Goliath beetle, Goliathus regius, found in western equatorial Africa is the largest of the group weighing in at 3.5oz! This beetle is about the size of a small apple or bar of soap. Not big by vertebrate standards, but huuuge for an insect.

image by opacity (Anne Petersen)

People find the look and docile behavior of these beetles very attractive and keep them as pets. The grubs, or larvae, of the Goliath beetle require a lot of protein while they develop but once the beetle reaches adulthood it relies on high-sugar foods like sap and fruit making them quite easy to care for. The Goliath beetle is also often used in insect fights; a spectator sport that capitalizes on the male beetle’s natural tendency to fight other males when a reproductive female is present.

So, as you can see, these insects couldn’t be more different from one another and yet they are both contenders for the title: The WOOOORLDSSS Biggest Insect!

Transcript of Insect Minute 3 – The Biggest Insect

Hi this is Heather with your Insect Minute brought to you by WKNC and the NC State Insect Museum.
“What is the biggest insect?”  Well that depends, is the longest or the heaviest
The longest insect is the Chan’s mega stick found in Borneo.  The walking stick can be over 1 foot in length! Can you imagine finding an insect the same size as your foot-long sub? Chances are slim any of us will see one, even if we do make it to Borneo because they are well camouflaged, looking just like the limbs of the trees they reside in.
The heaviest insect is only 4 to 5 inches long but what he lacks in length he sure makes up for in mass.  The aptly named Goliath beetle weighs 3.5 oz which makes this beetle about the same size and weight as a bar of soap. Imagine trying to lather up with this guy, the last thing you’ll be is squeaky clean.
If you would like to see pictures of these insects and find out more about them please visit the museum’s website at insectmuseum.org where you also find out information about the museum and read our blog where we talk about interesting stuff going on in the world of entomology.

Insect Morphology Seminar – foregut & infrabuccal pouch

Tuesday, February 21st, 2012

We began our exploration into the insect digestive system with Ann Carr’s lovely presentation on the foregut and the infrabuccal pouch. The infrabuccal pouch is a very neat structure that evolved independently in three orders: Hymenoptera, Isoptera and Coleoptera. It is basically a pocket in the mouth of an insect, like a termite, where it sequesters and “domesitcates” microbes that are used to aid in the digestion of its food.

What I found most interesting about her presentation is that there is an analogous structure found in Lepidopterans that is used for pollen digestion. The infrabuccal pouch of a Lepidopteran is similar in structure and found in the same area but has one big difference…SPINES!!!

check out this spine in the infrabuccal pouch of a Lepidopteran

These spines help to break down the pollen grains before they move into the foregut. I have been unable to find any publications or anyone that confirm whether there are microbiota in the Lepidopteran infrabuccal pouch. Which raises the question, is this a homonym? Meaning, is this a different structure deserving of a different name or is it a homologous structure? This also leads to our next…READER’S CHALLENGE!!

Can you find a paper that outlines the biotic makeup of the infrabuccal pouch in Lepidoptera OR can you find a paper that supports that this structure should be renamed as it does not serve the same function as the infrabuccal pouch in Hymenoptera, Isoptera and Coleoptera?

The winning paper of the week in our discussion group was, hands down, Keith Bayless with his paper about the evolution of flea-born transmission of bubonic plague in Yersinia pestis. I found this paper so interesting because, even as an entomologist, when I think of the PLAGUE I think of fleas passing it along with very little effort. It turns out that out of 2,000 species only 80 are even capable of harboring plague bacteria and the ones that can transmit the bacteria aren’t even that good at it! The flea only appeared to be excellent transmitters of the plague because they had such a close relationship with their host and could bite them (meaning us!) multiple times thereby increasing the chance of infection. There is a lot more interesting information in this paper and I encourage you to read it!

Other Papers This Week
1. The functional morphology of the honey stomach (aka crop) of the honey bee
2. Cephalotes ants and the special structures they have to harbor symbiotic organisms
3. Pretty cool paper on the proventriculus and the role it plays in the immunity of the tsetse fly
4. Ever wonder how starvation and parasitism effects foregut constriction in the midgut of Manduca sexta larvae? Here is your answer.
5. The contribution of the midgut bacteria of Aedes aegypti in blood digestion and egg production and how antibiotics affect it

Insect of the week – number 95

Friday, November 11th, 2011
Coccinella septempunctata

A seven-spot ladybug (Coccinella septempunctata).

Insect of the week – number 94

Friday, November 4th, 2011
long-necked ground beetle
A long-necked ground beetle (Colliuris pensylvanica) at a light in Durham, NC.

Insect of the week – number 91

Friday, October 14th, 2011

Insect of the week – number 90

Friday, September 23rd, 2011
Stethorus punctillum Weise
Great image of a Stethorus punctillum (Weise, 1891) specimen in Belgium, captured by Gilles San Martin.

Stethorus punctillum distribution
Distribution of Stethorus punctillum (Weise, 1891) in North America. Figure from Gordon (1985).