Friday 5: Milkweed Predators

A few weeks ago, I helped a coworker do a training workshop for the Monarch Larva Monitoring Project.  She’s been doing MLMP for multiple years, so she knows more about it than I do, but I’ve really enjoyed being a part of the project since my arrival in North Carolina.  It was a lot of fun teaching the workshop too!  The attendees seemed really happy to be identifying monarch caterpillars in the classroom, then doing it some more outside.  I think everyone went home feeling a sense of accomplishment, so I considered it a success!

The day following the workshop was a Saturday and, since my coworkers and I have to take turns doing weekend shifts, it was my turn to work the weekend.  When it came time to take a break, I did what I never had a chance to do during the workshop: I took my camera down to the milkweed where the attendees had found so many of their monarch larvae and shot some of them.  It was raining a little, but that didn’t deter me!  And I’m glad it didn’t because I saw a ton of great stuff on that milkweed, including several predatory species that were presumably eating the excessively abundant oleander aphids:

Aphids

Oleander aphids galore!

These predators included…

Ladybug

Ladybug

Ladybug eating an aphid

This is THE classic eater o’ aphids, and here you can indeed see one happily munching on an aphid.  It certainly had a lot to choose from!  It’s fun to remember that although so many people think of ladybugs as cute and adorable little beetles, they’re also predators that mercilessly chow down on other insects.  Nom nom nom!

Hover Fly Larva

There were several of these syrphid larvae on the milkweed:

Syrphid larva with aphids

Hover fly larva with aphids

According to our milkweed insect field guide (because what do I know about terrestrial fly larvae?), these flies are predators of aphids.  Go little fly, go!  Eat those aphids!  The more you eat, the more milkweed there is available for hungry little monarchs.  That fly will, as I understand, metamorphose into one of those great little yellow and black flies that hover a few feet above the ground.  I love everything about this larva, including the fact that you can see its digestive tract right through the exoskeleton.  Super cool!

Lacewing Larva No. 1

Lacewing with aphids

Lacewing larva with aphids

This lacewing wasn’t shy about its role as a predator and went scurrying about the leaves in search of aphids to eat.  I saw it catch and eat one, though I was so fascinated that I forgot to take a photo.  Oops!  Just imagine that lacewing with a nice, fat aphid in its mouth as it sucked down the aphid juice.  They’re fantastic little predators!  If you’re a gardener, these insects should become your best friends.

Lacewing Larva No. 2

Lacewing with aphid husks

Lacewing with aphid husk attire

Unlike the lacewing No. 1, lacewing No. 2 apparently felt the need for a disguise. If you look carefully you’ll notice that all that junk up on its back is discarded aphid exoskeletons, aphid husks!  I wasn’t able to find one of them, but some of these lacewings were positively covered in aphid husks so that you would never even expect an insect to be tucked away in the pile.  I am not sure whether these eat the aphids and then throw the husks on their backs (a sort of less permanent prison tattoo indicating the number of inmates this lacewing has killed) or scoop them up off the leaves and chuck them up there.  Either way, this lacewing was meandering more slowly around the leaf as it sought an aphid to eat than the lacewing above.  It was really fun finding two lacewing species with two totally different personalities!

And finally…

Itsy, Bitsy Spider

Spider

This was one of the smallest spiders I’ve ever seen!  It’s smaller than the aphids, and MUCH smaller than my fingers (which look positively enormous in this shot!), but it seemed to be going after the aphids nonetheless.  I can’t tell you anything more about this spider except that it was darling.  Look how tiny it is!  Adorable.

Milkweed is positively crawling with insects!  Apart from the aphids and their predators, I also saw ants herding aphids, a variety of wasps that seemed to be attempting to parasitize the aphids, some predatory flies, and a bunch of true bugs that were eating the milkweed.  Who knew that milkweed was such a battleground where every insect is in a life and death struggle for survival?  If you have milkweed in your area, I encourage you to visit it.  You’re likely to see some really cool things!

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Unless otherwise stated, all text, images, and video are copyright © C. L. Goforth

Friday 5: Fun Facts About Giant Water Bugs

This week’s Friday 5 features a subject near and dear to my heart: giant water bugs!  If you aren’t familiar with these beasts, they have some really amazing characteristics that make them a fascinating group of insects to study.  I’ve already covered giant water bug parental care and feeding in other posts.  Today I’m going to share 5 fun facts about giant water bugs.  I hope that knowing these facts will help you fall in love with these wonderful bugs!

Lethocerus medius

Lethocerus medius, the biggest giant water bug in Arizona, can reach lengths of nearly 2.5 inches!

1.  The largest true bug (i.e. member of the insect order Hemiptera) in the world is a giant water bug.

Lethocerus maximus is truly a giant, reaching nearly 5 inches in length!  However, if you want to add one to your collection, you’ll have to visit northern South America.  The Lethocerus in the US are piddly in comparison, topping out at about 2.5 inches – half the size of the biggest species.

Abedus cannibalizing eggs

A male Abedus herberti cannibalizing his own offspring after he scraped them off his back.

2.  Giant water bugs can be cannibalistic.

A hungry giant water bug will eat almost anything it can get its claws on, including its own young (only when very hungry or something has gone wrong with the eggs a male is caring for), the young of other individuals, and each other.  Female Lethocerus are also known to rip apart the egg clutches deposited by other females when there aren’t enough males with good egg laying sites to go round.  However, I haven’t observed giant water bugs eating each other in the field unless there is very little other food available and they are getting desperate.  It would seem they prefer not to eat each other, but they will when they have no other choice.

Abedus herberti mating

Abedus herberti mating.

3.  Giant water bug mating can take several hours, especially in the back brooding species.

Mating is a long, involved process in the back brooding giant water bugs.  First the male does little push ups in the water.  These are thought to send vibrations through the water that the females respond to.  After a male and a female find one another, they mate.  Then the female climbs on the back of the male and lays a few eggs, maybe 4.  Then the male shakes her off and they mate again.  Then she lays a few more eggs before being shaken off again.  This goes on and on until most of the back of the male is covered with eggs, sometimes 150 altogether!  You can see how this might take a long time.  The water bugs in the photo took over 6 hours to lay all of their eggs.

Belostoma micantulum

Belostoma micantulum, a giant water bug from Argentina, is one of the smallest giant water bugs in the world.

4.  Not all giant water bugs are giant.

Belostoma parvum, a giant water bug from northern South America, can be less than a centimeter long.  It’s a not-so-giant water bug!  In fact, several species of giant water bugs in the genus Belostoma are actually quite small and don’t live up to the “giant” in their name at all.  The giant water bug pictured here is Belsotoma micantulum, a tiny little giant water bug that maxes out at a little over a half an inch long.  Pretty cute though, especially when munching on a mealworm that is WAY too big for her!  :)

flood

The only flash flood I've ever personally witnessed, though it's hard to see how big this flood was in this photo! Clicking on the photo will take you to a cruddy, low-res video I shot of it and posted on YouTube.

5.  At least one species has a nifty flood-avoidance behavior.  

Imagine you’re an aquatic insect and a flash flood is headed your way.  You’re going to be ground into a bloody pulp if you stick around.  What do you do?  If you’re the giant water bug Abedus herberti, you climb out of the stream before it floods!  This species crawls out of the water and walks perpendicularly to the bank until it reaches shelter away from the stream.  After the flood passes through, it crawls back into the water and carries on with its regular activities.  Awesome behavior!  And you can see a video of it online by visiting Dr. Dave Lytle’s website.  He filmed Abedus herberti leaving the stream after artificially simulating flood conditions with a fire hose.  The video is hilarious, so I encourage you to take 30 seconds out of your day to watch it.

Aren’t giant water bugs cool?  I love my bugs.  Considering they mostly just sit in one place hoping that food will swim by, it never ceases to amaze me just how many wild characteristics these bugs really have.  Hope you enjoyed this little peek into some of the many fascinating things these bugs have going for them!

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

More giant water bugs eating

I’ve been super busy with work recently and haven’t had time to put together one of my normal, long-ish blog posts.  But, I wanted to get SOMETHING up this week!  This will be short on words, but hopefully big on the wow value.

Several weeks ago, I wrote a post on giant water bugs eating and included a video of the medium sized species we have in Arizona (Abedus herberti) eating a mealworm that I gave it.  That post details how giant water bugs eat, so I recommend that you check it out for more detailed information on what you’ll see here.  Abedus herberti isn’t nearly as big as another Arizona native, Lethocerus medius, and while it’s mode of eating is still impressive, it’s nothing compared to what L. medius can do.  Species in the genus Lethocerus are the largest true bugs on the planet and are real powerhouses when it comes to taking down vertebrate prey.  These bugs are big, so they can eat really big things like snakes, turtles, frogs, fish, and birds.  So, in my insect behavior class we fed a goldfish to the Lethocerus medius we’d been experimenting with all semester, a goldfish that was about the same length and likely much heavier than the bug.  The bug hadn’t eaten for over a week to prepare it for the goldfish demonstration.  This was the result:

Now if that isn’t the coolest thing ever, I don’t know what is!  This right here should be enough to convince anyone that giant water bugs are the best insects one Earth.  (Okay, okay – so I’m a little biased!)  Now normally this bug would just sit in one spot and wait for food to swim by (they’re called sit and wait predators for a reason), but not this one.  He was so hungry he actually hunted down and captured his food before eating it.

Next up will be my one-year anniversary post.  I can’t believe I’ve been at this for a year already!  This calls for a celebration.  I might even give something away as a reward for sticking with me this long…

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Unless otherwise stated, all text, images, and video are copyright © 2010 DragonflyWoman.wordpress.com.