Well-Nigh Wordless Wednesday: Scary

You know what’s kinda scary?  Tarantula hawks.  They’re beautiful and interesting to watch and will completely leave you alone if you leave them alone, but they’re also big and rank really high on the Schmidt Sting Pain Index.  Know what’s even scarier?  Finding this on your kitchen counter one morning when you’re on your way to make a much needed caffeinated beverage:

dead tarantula hawk

Dead tarantula hawk

Dead tarantula hawks in the house mean that live tarantula hawks were flying around inside your house at one point.  *Shudder*

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Unless otherwise stated, all text, images, and video are copyright © TheDragonflyWoman.com
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Sexing Giant Water Bugs

Female giant water bug

Female giant water bug

I am asked how to tell male and female giant water bugs apart more often than I would have ever imagined.  It would seem that there are a limited number of people in the world who can sex water bugs, so I have a rather steady stream of people asking me how to do it.  A few weeks ago I started looking around online to see if there was any information about sexing water bugs, but there’s really nothing available.  Well, there’s one article that is absolutely and completely wrong (I’m not even going to link to it, but don’t listen to anything the person who wrote the eHow article on the subject says!), so that’s no help at all.  It’s high time that this information be made available online!

Sexing belostomatids (aka, giant water bugs) isn’t always trivial.  The males and the females have the same coloration, so you can’t use color differences.  The females are often a little bigger than the males, but there’s a lot of variation in size in both sexes and it can be difficult to tell whether an individual is “big” or “small” unless you have many other individuals to compare with it.  You can sometimes use behaviors to distinguish sexes, especially during the mating season.  For example, if a bug is carrying eggs on its back or climbing up a stick to tend to eggs, it’s a male.  But… you also can’t be sure you have a female just because one doesn’t have eggs, even during the peak of the mating season.  Instead, you need to rely on a structure that varies reliably between the sexes.

Giant water bugs DO bite, but you’re going to have to hold them in place if you want to tell which sex you’ve got.  That usually involves picking them up, so if you do choose to sex water bugs yourself, be careful!  When I pick up water bugs, I use my middle finger and my thumb and press the bug down onto the bottom of whatever habitat/container they’re in.  I then grasp water bugs by the sides of the thorax, as it’s a very rigid part of the body where you can get a firm grip, and use my index finger to support the bug (I apologize that I only have a grainy black and white photo of this…):

Holding giant water bugs

Holding giant water bugs

You need to hold on tight, especially with the larger species, because they are surprisingly strong and will try to wiggle free.  Once you get a good hold on one, you’ll need to flip it over.  The part you need to look for is on the bottom of the abdomen:

Genital plate

Genital plate

This structure is called the genital plate, and it conceals the reproductive organs underneath.  Don’t worry!  You don’t need to go digging around to find internal parts and can use the shape of the genital plate itself.  The shape of the plate varies from genus to genus, but there are some general rules.  The genital plates of male water bugs are smoothly rounded at the tip (the part closest to the back of the bug) and complete (i.e., have no splits or gaps).  For example, the genital plate of males in the genus Abedus look like this:

Abedus male genital plate

Abedus male genital plate

The arrow points to the continuous and smoothly rounded tip of the genital plate.  Here’s a drawing in case the shape is difficult to see in the photo:

Abedus male genital plate

Abedus male genital plate

See?  Rounded at the tip, no splits or gaps.  The females are different.  In some water bug genera, there are splits, notches, or gaps at the tip of the genital plate, so that the line around the tip of the plate is broken.  Many of them have flattened areas at the tip of the genital plate so that they are not completely round.  Most have two distinct little tufts of hairs, either at the edges of a notch at the tip of the genital plate or alongside the midline of the genital plate near the tip.  For example, here’s a female Abedus:

Abedus female genital plate

Abedus female genital plate

In this image, the arrow pointing up from the bottom indicates the flattened, slightly notched part of the genital plate while the arrow coming from the side points to the tuft of hair on the right side of the midline.  The drawing:

Abedus female genital plate

Abedus female genital plate

The little tufts of hair can be quite small and the shape of the genital plate only subtly different from the male, but there are definitely two little tufts of hair on either side of the midline, a flattened area at the tip, and a small split at the tip of the genital plate in Abedus females.

These structures can vary in appearance from species to species, and especially between genera.  For example, this is the genital plate of a male Lethocerus:

Lethocerus male genital plate

Lethocerus male genital plate

Even though it’s much longer and narrower than Abedus, the arrow indicates the same sort of rounded, unbroken tip of the genital plate.  There is a fringe of hair along the tip of the plate in this species, but note that there are no distinct tufts of hairs anywhere.  There’s a groove that runs the length of the middle of the plate, but it doesn’t leave a gap at the tip.  In contrast, here’s the female:

Lethocerus female genital plate

Lethocerus female genital plate

The arrow here points to the tuft of hair to the right of the midline.  In this species, the tufts are at the very tip of the genital plate rather than on the upper surface and recessed from the edge as in Abedus.  There is also a small notch between the two tufts, though it’s a little difficult to see in the photo.

And that’s it!  Smooth, round genital plates in males and flatter, sometimes broken genital plates with two tufts of hairs in females.  In the US, the genital plates of the genus Belostoma are very similar to those shown here for Abedus and other American Lethocerus are similar to the Lethcerus pictured here, so the images here will help with sexing US water bugs.  Other genera in other countries follow similar patterns, but may have some slight differences.

Good luck!

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Swarm Sunday – 2011 Year-End Report, Part 3

Dragonfly Swarm Project logo

It’s time for part 3 of the year-end report for the Dragonfly Swarm Project!  This week: the conclusions.  I’m going to divide this post up into sections to make reading through everything a bit easier, each with its own conclusion.

Conclusion 1: In the United states, dragonfly swarms are more common in the east than the west.

I made a similar conclusion last year, but the pattern has held true a second year and I feel it bears repeating.  I still think that the reason for this pattern has to do with the availability of large bodies of water.  Rather than writing it all out again, I’d like to direct you to last year’s conclusion #1 for more information on the importance of water for dragonfly swarms.  If I’m right about a water-swarm connection, then I should expect to see the same patterns over the next few years.  I therefore make a prediction:

Prediction 1. Dragonfly swarms will continue to be much more abundant in mesic/hydric areas with large bodies of water than in arid regions.  Thus, dragonfly swarming will be most commonly reported east of the Missouri River in the US.

water in East vs West

East vs. West – clearly one is more arid than the other!

Conclusion 2: Flooding and heavy rains are strongly associated with static dragonfly swarms.

People kept talking about flooding in their weather reports this year, so I added a specific question about flooding to the report form, even though the season was half over when I did so.  Based on the data collected from that point on, over 2/3 of all dragonfly swarms are associated with floods or heavy rains that occurred sometime within the month prior to the swarm.

I think there is an obvious reason for this.  Mosquitoes, other aquatic insects, and various terrestrial insects (including the flies commonly lumped into the “gnat” group) may take advantage of available water to increase their population sizes.  Flooding and heavy rains in an area can leave big lakes/pools of water behind where none were previously, and these are prime breeding grounds for mosquitoes and other aquatics.  Sodden soils can also lead to explosions of small flies.  (“Bugnadoes” were reported in many areas along the severely flooded Missouri River this summer.)  If things stay wet for a while, molds can grow and allow yet other insects to experience population booms.  Prolonged wet conditions create perfect conditions for dragonfly swarms: lots of little flying insects (aka, dragonfly buffet!) concentrated in specific areas.  Thus, heavy rains and floods lead to prey population booms, which in turn attract dragonflies to the area, which then leads to swarming.

There’s a lot of evidence to support this conclusion.  Rains mixed with heavy snowmelt in Colorado and several rivers flooded in early to mid-June.  In early July, there was a small surge in reports from Colorado where there had been hardly any the year before.  The Missouri River flooded from late May until Mid-June and remained flooded for many months afterwards.  There were many more reports in the Missouri River area this summer than last.  Also, remember that huge swarming event that happened in the northeast, the one that resulted in hundreds of reports in Ohio, Pennsylvania, Virginia, and West Virginia?  Hurricane Irene hit the mid- to north Atlantic coast August 27th and 28th, causing flooding in some of those areas.  There were also heavy rains in Pennsylvania that created pools of standing water and sodden soils prior to the hurricane.  The surge in swarm reports began only a week later.  Over 400 reports came in from the four state area over the next three weeks. Based on this evidence, I make another prediction:

Prediction 2. Most swarms reported in future seasons will follow flooding or heavy rains.

Aerial view of MO River

Aerial view of Missouri River flooding in early September, over 3 months after the flooding began.

Conclusion 3: There were fewer swarms reported in the Midwest this year because they experienced flooding last year.

In 2010, there were major swarming events in Minneapolis, over large parts of Iowa, and in other areas of the Midwest that coincided with flooding.  In contrast, this year there were comparatively few swarms reported in that part of the country.  My hypothesis: flooding kills/displaces the developing nymphs so that relatively few dragonfly adults emerge the next year.

Flooding is generally bad for insects.  Though some insects have figured out ways to avoid floods (including at least one species of giant water bug), flooding is dangerous for most aquatics, including dragonflies.  A flood can decimate the nymphal dragonfly population by grinding them up in sediment loosened by the flood, washing them downstream, or leaving them stranded on land as the waters recede.  The next generation of dragonflies can be effectively eliminated by floods, resulting in far fewer dragonfly adults emerging the following year.  However, dragonflies are mobile creatures and some will find their way into areas where flooding has occurred in the past.  They’ll go about their regular business of setting up territories and mating, generating a new population of nymphs that will emerge as adults sometime within the following few years.

I think this is what happened in the Midwest.  Last year there was a lot of flooding, so this year there weren’t enough dragonflies in the area to form swarms.  Thus, I observed a sharp decrease in the number of swarms reported along Lake Michigan, the Wabash River, and the Mississippi compared to 2010.  I mentioned last week that I didn’t see the same migratory paths down the Wabash and Mississippi Rivers this year as I did in 2010.  I think it’s because there was so little swarming in the northern Midwest this year that there simply weren’t enough dragonflies to form the big migratory swarms that people actually notice.

Of course, I could be totally wrong!  It could be that the lack of flooding itself in the northern Midwest this year compared to last means that fewer swarms were forming and reported there.  It might not have anything to do with nymphal dragonfly populations at all and everything to do with the amount of water itself.  To test my hypothesis that flooding the year (or two) prior leads to a decrease in swarming in an area, I predict:

Prediction 3. There will be more dragonfly swarms reported from the northern Midwest (Minnesota, Michigan, Wisconsin, northern Illinois, Iowa, etc) in 2012 than in 2011.  Similarly, there will be very few reports of swarms from eastern Ohio, Pennsylvania, Virginia, and West Virginia in 2012.

Midwestern field

Midwestern field. This is the kind of place I would expect dragonfly swarms to form, but will there be swarms here next year? It’s close to the Mississippi River, which flooded horribly in spring 2011.

Those are my three main conclusions for the year!  Ultimately,  I think dragonfly swarming all comes down to weather.  Migrations are certainly weather driven, but the static swarms are weather related too.  Perhaps not directly in many cases, but weather patterns can lead to localized increases of prey in an area, which in turn leads to static swarm formation.  It will be very interesting to see how weather patterns contribute to swarm formation over the next 3+ years!

Next week, I’m going to do one final post about the Dragonfly Swarm Project for 2011.  I want to share some more of those swarm stories I get and I’ve got a few last thoughts to wrap up the season.  Then, I’m going to start doing something else on Sundays, at least until the 2012 swarming season begins.  Look for big changes in a few weeks!

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Have you seen a dragonfly swarm?

I am tracking swarms so I can learn more about this interesting behavior.  If you see one, I’d love to hear from you!  Please visit my Report a Dragonfly Swarm page to fill out the official report form.  It only takes a few minutes!

Thanks!

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Want more information?

Visit my dragonfly swarm information page for my entire collection of posts about dragonfly swarms!

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Unless otherwise stated, all text, images, and video are copyright © TheDragonflyWoman.com

Friday 5: I Am Thankful to Be An Entomologist

Yesterday was Thanksgiving in the US, a time to eat tons and tons of food (enough that you either want to die, just a little, or pass out into a total food coma) and give thanks for the good things in life.  Regardless of whether I spend Thanksgiving with my family or my husband’s (my husband’s this year), there is one tradition that we follow: we go around the table saying what we’re thankful for before we eat.  I’m thankful for many things, but some things I choose not to share at the table.  Like how I love insects and I’m thankful to be fulfilling my long-term dream of becoming an entomologist.  But I can write about that here!  In the spirit of a good, old-fashioned American Thanksgiving, I thus present my entomologically themed list of thanks: why I’m thankful to be an entomologist.

There are so many insects!

You all know that there are a lot of insects in the world.  The number of insects on the planet at any given time is astounding.  (How do you even conceptualize the idea of a quintillion, the number of insects a quick online search suggests are on Earth at any given time?)  There are also more insect species on the planet than all other animal species combined.  If you want to be a scientist and you need to find a little niche to call your own, you could definitely do worse than entomology.  There are so very many research opportunities!  It’s a big field and many subjects are still wide open, ready to be researched, so it’s a great science to be a part of.

insect display

Insect display. This is a tiny handful of the species on the planet!

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INSECTS ARE UBIQUITOUS

There are insects nearly everywhere on Earth except the ocean (a topic for another time).  They can be found living on land, in streams and lakes, in wastewater, in soil, in trees, in plants, in sheep, in humans, on humans, in little pools of water inside tropical plants, in grain storage facilities, in cheeses, on snow fields, and at the base of glaciers.  There’s even a type of aquatic fly larva that is found in pools of petroleum!  Nearly anywhere you go on our planet you can find insects to study.  I think that’s simply amazing.

Carpenter bee nest

Carpenter bee nest. There are insects in there!

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Insects are beautiful

I feel that people would appreciate insects more if they would take a moment to discover how incredibly beautiful they are!  It makes me so happy that artists such as Joseph Scheer and Thomas Shahan share the beauty of insects with the world.  Even if you hate spiders, how can you not appreciate the charisma and stunning structure of one of Shahan’s jumping spiders?  How can one not see beauty in the delicate perfection of the wing scales on one of Scheer’s giant moth images?  Even something like my water bugs, which the vast majority of people I meet think are rather gross, are beautiful to some extent.  The structure of their eyes, the leafy patterns on the backs of the bigger species, the different structures used to breathe… All stunning if you take a moment to look.

Libellula saturata

Female flame skimmer, Libellula saturata

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Entomologists make great friends

I find entomologists to be, by and large, incredibly kind and wonderful people.  I have friends who don’t like insects of course, but those friends sadly don’t share my intense love for a group of rather unloved animals the way other entomologists do.  Entomologists get each other in a profound way.  I knew i was joining the right group of people when I came to Arizona to interview for grad school, saw a tarantula hawk (a REALLY big wasp for those of you who aren’t familiar with them) fly overhead, and nearly everyone in the group looked up and watched it fly by like it was the most interesting thing in the world.  I love being around other entomologists (and here, I’m including all of you non-scientists or non-entomologist scientists with entomological leanings) because they share my love for insects, and are really, really good people to boot.  And, if you’re not an entomologist, it’s still good to have us around!  Who else can tell you whether the spider in your house is poisonous (probably not) or whether the strange pile of lumps under your beam is caused by termites?  :)

Friends Collecting

Some of my entomologist friends collecting together

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Insects make me appreciate the natural world

Nothing makes you appreciate how marvelous the natural world is like insects.  Just ponder it for a moment: there are approximately a million insect species described in the world, and there may be 1-10 million more than we don’t even know about yet.  Insects live nearly everywhere (see above), exhibit some of the most bizarre and/or beautiful behaviors imaginable, and display hugely diverse structures and color patterns.  The fact that all these species, all these forms, all these behaviors exist in a single animal group is nothing short of miraculous.  I see the wonderful beauty of the natural world reflected in insects.  And for that reason alone, I am thankful to be an entomologist.

Leafhopper

Something as common and mundane as a leafhopper can be marvelous

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Unless otherwise stated, all text, images, and video are copyright © TheDragonflyWoman.com

Happy Thanksgiving!

The ants (and one ant mimicking spider) wish you a very happy holiday:

Thanksgiving ants

(Okay, okay, so I drew this myself, but it IS possible to actually get ants to spell words like this with live ants.  Don’t believe me?  Check out Biocreativity’s post on making fire ant art!)

I hope everyone has a very great Thanksgiving!  Or just a great day if you don’t live in the US and are not stuffing yourself silly with poultry and starches today. :)

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Unless otherwise stated, all text, images, and video are copyright © TheDragonflyWoman.com

 

Well-Nigh Wordless Wednesday: Jumper

Since BugShot 2011 concluded, I’ve seen a surge in the number of jumping spider photos appearing online. This is probably because Thomas Shahan, one of the best jumping spider photographers in the world, was one of the instructors and everyone wanted to try their hand at his techniques when they got home. (He takes his photos with cheap, old camera equipment he picks up at garage sales by the way!)  Today I’m jumping on the jumping spider bandwagon myself and give you my best photo of these little, terribly charismatic spiders:

jumper

Hello!

I clearly have a long way to go. :)

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Unless otherwise stated, all text, images, and video are copyright © TheDragonflyWoman.com

Shooting Insects with an iPhone + Olloclip

As you can probably tell from my blog posts, especially the one raving about BugShot 2011, I am in love with insect photography!  There’s something about pulling a camera out and shooting outside for an hour or more that makes me supremely happy.  However, my current DSLR setup is an absolute behemoth and is absolutely not a portable camera for taking to, say, the grocery store in my bag.  Instead, I’ve carried my Canon G11 point and shoot with me for the past 2 years.  It’s much smaller and takes great photos, but it’s surprisingly heavy and doubles the weight of my bag.  My iPhone, on the other hand, is a lightweight and portable camera.  It also takes decent photos so long as I don’t need to zoom in.  Or take photos in low light.  Or photograph small things, such as insects.  That last trait is a bit of a problem for me, but I’m determined to turn my iPhone into an insect photograph taking machine!

My main concern was getting closer to my subjects.  Happily, there are solutions for this!  You can simply tape a 10x hand lens over the camera lens and increase the magnification of the iPhone camera.  It’s a cheap camera hack, but it requires a bit of setup work and isn’t a fast option when I find an insect running down the sidewalk that I must have a picture of RIGHT NOW!  Instead, I’ve looked into the PhotoJojo and Olloclip “macro” lenses for iPhone.  These lenses provide magnification, but are easier to use than the hand lens method.   The PhotoJojo 3 lens set is $25 cheaper than the Olloclip, but to use them you also have to stick a big magnet on the back of your phone.  The Olloclip slides over the phone’s frame instead, so I thought it was probably worth the extra cash.  As luck would have it, I happened to win a cash prize days after I decided I wanted to buy the Olloclip, so I ordered it and waited impatiently for it to arrive.

The Olloclip looks like this:

Olloclip

Olloclip

And it looks like this attached to the phone:

Olloclip on phone

Olloclip on iPhone

The device is two-sided, so depending on which of the three lenses (“macro,” wide-angle, or fish eye) you want to use, you simply slide it over the frame so that your choice of lens sits over the camera lens.  To use the macro lens, you unscrew the wide-angle lens from the Olloclip and it’s ready to use!  It’s a very simple device.

But would it work for insect photos?  I immediately pulled out a box of bugs and selected a few to photograph.  This was one of my first shots, dragonfly wings:

Dragonfly wings

Dragonfly wings

It worked pretty well for that.  The photo was taken indoors under artificial light with a still (dead) subject.  I did have to edit the image to correct the white balance, but that was an easy, minor fix that I could do on my phone.  It’s all well and good that the Olloclip could take photos of a flat, non-moving object, but would it work on a  bigger insect with some depth?  This is how a photo of a midas fly looked, after some color correction for the overhead fluorescent lights:

midas fly

Midas fly

Not half bad!  The Olloclip was able to pick up on some of the surface details of the fly.  So I took my phone + Olloclip outside, because this is ultimately where I’ll be using it.  I photographed a few leaves, then came across an enormous grasshopper.  (Yes folks, it’s November in the Sonoran Desert!)  I moved the phone toward it to try to get a shot… and scared it horribly.  It flew directly into my face, which scared me horribly.  That photo didn’t turn out so well.  But I wasn’t deterred!  I shot some more photos of leaves and a few other things.  This was the best of the bunch:

Leaf

Leaf

This was not as promising.  The photo was blurry, even though I was anchoring my arms against my body AND supporting the leaf with my other hand to prevent it moving in the wind.  Clearly there were a few issues to deal with…

I’ve played with my Olloclip for about a week now and I’ve discovered several limitations.  For one, the lens has virtually no depth of field.  While I can easily photograph something flat, photographing anything with depth leaves most of the image out of focus.  I’ve produced some dreamy shots of plants, but my attempts at insects have been mostly disappointing.  In addition to the depth of field issue, you have to be very close to the subject, within a half-inch, to get the camera to focus.  This is awfully close for some insects, as the grasshopper incident proved.  And, when you’re that close, every tiny movement looks like a very big movement to the camera!  I’m having some issues with motion blur, which is not ideal for photographing mobile insects. There’s a fair amount of noise on all the photos.  Finally, and I just learned this today, screen protectors and the Olloclip really don’t mix.  I ripped mine right off when I saw a trap jaw ant I wanted to photograph today!  Really annoying.

The verdict: the Olloclip is a fun little device, but not ideal for taking crisp, clear photos of insects.  It does produce some lovely botanical images and the wide-angle and fish eye lenses are great, but my iPhone will not be replacing my point and shoot for insects any time soon.  I took a shot of the midas fly with my point and shoot under the same conditions to compare the quality:

Midas Fly

Midas fly - with point and shoot

Much better!  Guess the point and shoot is worth the extra weight after all.

Do any of you have any suggestions for other things I can try to improve my iPhone’s camera so I can stop carrying my beast of a point and shoot around?  If so, please leave a comment!

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Unless otherwise stated, all text, images, and video are copyright © TheDragonflyWoman.com