Posts Tagged ‘Insect Minute’

Insect Minute – Cicadas

Friday, July 27th, 2012

If there is an insect that represents the feeling of summer, I would argue it is the Cicada. At an afternoon baseball game or cook out, a chorus of male cicadas are there providing a soundtrack, doing their most animated singing at the warmest point of the day. This association between summer and cicadas is not unique to North Carolina or North America for that matter. Cicadas are found on every continent, with the exception of Antarctica.  In fact, there are 2,600 described species in the world ranging from very large (110 mm) to relatively small (14 mm), most of which are members of the family Cicadidae. The other family of cicadas, Tettigarctidae, is a very small and relictual group that is represented by two species present only in Australia. These Australian cicadas are known as the hairy cicadas and communicate by transmitting vibrations through vegetation instead of singing like the Cicadas we are familiar with.

The members of the family Cicadidae sing using organs called tymbals which are located on the abdomen of the males. The tymbal is like a drum. A complex membrane with taenidia-like striations running parallel along the surface and as the membrane vibrates and the enlarged chambers within the trachael system in the insects body act as a resonating chamber.

Image from Cicada Mania

Image from what-when-how

The males use the tymbals to attract females and have distinctive calls to ensure that they attract the females in their species. Males and females have tympana on the underside of their abdomen which the females use to hear and orient toward potential mates, while the males use the tympana to identify competeing males.

Image from Cicada Mania

The life cycle of cicadas is pretty neat, a female cicada will lay eggs into the twigs of a woody host plant using a lance-like ovipositor. When the nymph hatches it drops to the ground and, using it’s fossorial legs, burrows into the soil where it spends the majority of its life feeding on juices it sucks from tree roots. The cicadas we are that we hear every summer are known as the dog-day or annual cicada. The latter name is actually a misnomer. Many believe that the dog-day cicada has a one year life cycle when in fact they live under ground for up to 8 years before they emerge. Because they emergence patterns are asynchronous they do not make as big of an impression. When it is time for cicadas to come above ground the nymph will dig to the surface, climb part way up the tree and molt into its adult form.

The periodical cicada get the most attention because of the grand synchronized emergence that occur every 13 to 17 years. These cicadas are in the genus Magicicada, which looks a lot like magic cicada. That is not too far off when you consider that no one knows exactly how they time their appearance. What is it that signals all the members of a brood to emerge at the same time? Some researches have hypothesized that it is a temperature shift, others believe it could be that the cicadas are tracking the seasonal changes in their host plant until they reach 13 or 17 cycles. It could be a combination of both or something else entirely but because they are so long lived it is hard to pinpoint the reason.  Regardless of how they do it, it makes an impact on anyone who is lucky enough to experience it.

photo by billy liar

If you would like to learn more about cicadas there are plenty of websites dedicated to them. They are such enigmatic little creatures it is no surprise!

  1. DrMetcalf database http://www.lib.ncsu.edu/specialcollections/digital/metcalf/cicadas.html
  2. Cicada Mania http://www.cicadamania.com/cicadas/
  3. Track brood emergence of Magicicadas at http://www.magicicada.org/magicicada_i.php

Transcript of Insect Minute 4 – Cicadas

Hi this is Heather with your Insect Minute brought to you by WKNC and the NC State Insect Museum.
Do you love the sound of cicadas singing on a warm summer night? Typically the serenaders you hear are Dog Day Cicadas, which have broods that emerge every year. But, if you were in Wake County in the summer of 2011 you may have heard a different sound. The sound of hundreds of thousands of periodical cicadas singing in unison! These infrequent visitors are in the genus MAGICICADA. Magicicadas have an amazing life history. They live underground as nymphs for 13-17 years feeding on the juices they suck from tree roots. Then, in a synchronized emergence they take to the trees where they molt into their adult forms, feed and mate. Magicicadas have black bodies, orange wing veins and striking red eyes. The dog day cicada has green wing veins and lack red eyes, making the red eyes a key distinguishing character.
Guess what is coming in 2013? You got it; North Carolina will see another grand emergence of magicicadas. So keep your eyes to the trees and your earplugs at the ready!
If you’d like to learn more about the cicadas visit the museum’s website at insectmuseum.org where you find out more about the museum and read our blog where we talk about interesting stuff going on in the world of entomology.

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 Minute – The Arctic Woolly Bear Moth

Friday, July 13th, 2012

As a kid in North Carolina, many of us grew up with the notion that banded woolly bear caterpillars could be used to predict the severity and length of the coming winter. If the band around the center of the caterpillar’s body was wide, we knew we were in for a winter full of snow days and sledding! I am sorry to report that this is, indeed, a wives’ tale. There can be a lot of color variation within one clutch of banded woolly bear caterpillar eggs and the band width typically grows with age. Disappointed? Me too.

Banded woolly bear - Photo by graftendno1

Never the less, there is a woolly bear caterpillar that does have a very interesting relationship with winter. It is called the Arctic woolly bear caterpillar. Although their names are similar and they superficially look alike, these two are very different. The banded woolly bear caterpillar is in the family Arctiidae and is common in all of North America. The arctic woolly bear is member of the family, Lymantriidae, and is found in the Arctic Circle.  This is where is gets really interesting, folks.

The banded woolly bear has two broods in the summer, the first of which pupates and emerges in the same year, the second will pupate over winter and emerge the following spring. The life cycle is very different in the Arctic. Due to the brief growing season, the caterpillar has to feed for several summers to achieve the critical body mass it needs to pupate. As the arctic woolly bear awaits the coming summers it overwinters as a caterpillar, hiding in a hibernacula, allowing the body to freeze, relying on cryoprotectants, such as antifreeze compounds, to minimize permanent tissue damage caused by temperatures nearing -60°C. When the summer returns the caterpillar thaws, reanimates and returns to feeding. This cycle can repeat up to 14 times, meaning 14 years (!) of freezing and thawing and eating, before it pupates and becomes an adult. However a 1998 study by Morewood and Dean showed that it is more common for the cycle to continue for 7 years before pupation. Still, quite impressive!

Arctic Woolly Bear from Discovery documentary, Frozen Planet

Transcript of Insect Minute 2 – Arctic Woolly Bear:

Hi this is Heather with your Insect Minute brought to you by WKNC and the NC State Insect Museum.
The Arctic circle is an unlikely place to find an insect, right? WROOONG! Insects are everywhere and have adapted cool strategies for contending with harsh conditions. The Arctic Woolly Bear Moth is native to this extreme environment. Upon emerging from its egg, the caterpillar begins to eat voraciously. As summer comes to an end it finds a rock to hunker down on and as the arctic freezes over, so does the caterpillar. When the thaw returns the following June, the caterpillar reanimates and returns to its frantic feeding schedule. The cycle is repeated 7 times, which means this moth lives as a caterpillar for 7 years, freezing and defrosting every year. It survives by producing a kind of antifreeze in its blood which protects vital areas from freezing. In the final year the caterpillar develops into an adult, mates, lays eggs and the cycle for the next generation begins.
If you’d like to learn more about the arctic woolly bear 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.

Want to read more?

  1. Morewood, W. Dean & Richard A. Ring (1998). “Revision of the life history of the High Arctic moth Gynaephora groenlandica (Wocke) (Lepidoptera: Lymantriidae)“. Can. J. Zool. 76 (7): 1371–1381. DOI:10.1139/cjz-76-7-1371
  2. ARCTIC WOOLLY BEAR WEBSITE (!!!) – http://www.arcticcaterpillars.org/Site/Arctic_Woolly_Bear/Arctic_Woolly_Bear.html
  3. Bennett, V.A., Lee, R. E., Jr., Nauman, J.S. and Kukal, O. (2003) Selection of overwintering microhabitats used by the arctic woollybear caterpillar, Gynaephora groenlandica. CryoLetters 24(3): 191-200.

Insect Minute – The Wonderful World of Bees!

Thursday, June 21st, 2012

Furry, colorful and industrious bees radiate a charisma that people are naturally drawn to. After all, they produce the celebrated product, honey, and pollinate crops and gardens. Like most people, I knew there were three kinds of bees: the honey bee, the bumblebee and the carpenter bee. What I did not realize until I started studying bees, is that there are over 20,000 species of bees world wide and that these represent only a small portion of the bee diversity out there. There are over 3,500 species in the United States!

Bees are in the order Hymenoptera which also includes wasps, ants and sawflies. Bees and wasps are commonly confused with one another or perceived as names that are interchangeable. Bees and wasps share some attributes; like a similar body plan and they are both holometabolous insects. (A much cuter explanation of metamorphosis) There is one very big thing that sets them apart, their diets! Bees are strictly vegan, preferring to forage on pollen and nectar, whereas most wasps mix other arthropods into their diets.

Common Misconceptions:

  1. Bees bite: Well, not usually. Bees have mandibles but they do not typically use them in defense. The main mode of defense is the stinger, a modified egg-laying structure, found only in females. Males are largely defenseless.
  2. Bees and Wasps are the same thing: It’s true that they are related and very similar anatomically, but there are some major differences. As mentioned above, their diet. Most bees are much fuzzier than wasps, having branched hairs that help them collect pollen.
  3. All bees live in hives: Honey bees do, but most bees are solitary which means they live on their own provisioning their brood cells with pollen and nectar. They typically rest on the backs of leaves, in crevices, or in their unfinished brood cell.
  4. Bees attack people: When a honey bee hive is disturbed the bees may give chase, but most bees will not. In this instance the bees are defending their hive and are attempting to scare off a perceived danger to the colony. Typically bees, including foraging honey bees, are quite docile and are unlikely to react to your presence. In my studies working with bees, I have petted a bee on it abdomen while it foraged and it responded by simply flying away.
  5. Bees are only black and yellow: So not true!! Many are black with some hue of yellow, but they come in a rainbow of colors. Check out this beautiful metallic green sweat bee. Gorgeous!

photo by bob in swamp

Transcript of Insect Minute 1 – Bees:
Hi this is Heather with your Insect Minute brought to you by WKNC and the NC State Insect Museum.
When you think of bees you may immediately think honey bee or perhaps the fuzzy bumble bee or a wood loving carpenter bee that is boring holes into your back porch as I speak.
BUT BEES ARE SO MUCH MORE DIVERSE!
You may be surprised to find out that there are over 20,000 different species of bees in the world! and that there are over 3500 here in the United States. Most bees are not social like honey bees. They may live as solitary insects or in small groups with a queen and a handful of female offspring to assist in collecting pollen and nectar for the next generation.
Bees also come in a myriad of colors…
We are all familiar with yellow and black bees, but they also come in green, blue, purple, and even rainbow! It is their diversity that makes them able to occupy many different habitats and act as effective pollinators!
If you’d like to learn more about the diverse world of bees visit the museum’s website at insectmuseum.org where you find out about our museum and read our blog where we talk about interesting stuff going on in the world of entomology.

Podcast to come soon!