On Guard

When you take time to smell the flowers, or rather peer at the onions, you find some pretty cool stuff.  This week, Simon shared with me another little gem of nature: parasitized natural enemies.  Just a reminder, parasitoids develop internally on their host, usually killing it.  This particular case of parasitism, however, is atypical in that the host does not die

Image courtesy of Maure et al. 2011

The victim of the story is the common Pink Lady Beetle, Coleomegilla maculata, affectionately called C-mac in some circles.  C. maculata is a generalist predator, feeding on aphid species and other small soft bodied insects.  I’m not surprised to see many of them in the onion fields.  In this case, a parasitic wasp, Dinocampus coccinellae, lays a single egg inside its beetle host.  Rather than killing the host, the wasp larva emerges and spins its pupal casing around the legs of the ladybug, keeping it in place.  Thereby, providing its own bodyguard to protect it from predation and hyperparasitism (parasitoids that parasitize other parasitoids…that’s a lot of parasitism). This article was just published online about the system.  Pretty cool!

Image courtesy of Stippen.nl

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Helmets!

My niece has a doll with a bonnet.  It looks like it’s wearing a helmet.  So she named it Baby Helmet.  It turns out, that these guys have helmets too.

Photo Courtesy of Greg Lasley

This is a treehopper, in the family Membracidae.  This species is the Thorn Treehopper, Umbonia crassicornis, found in the Southern United States.  The helmet is the pretty green, yellow, and pink structure that creates the thorn-like appearance.  A recent article published in Nature found that the helmet is an appendage arising from the first thoracic segment.  Somehow it’s “escaped” the repressive function of the gene that leads to wing formation.  It’s almost as if treehoppers had a third pair of wings.  But not quite, they’re just wing-like.  They’re fused together, not used for flight, practical for mimicry, and in my opinion, make treehoppers look really cute.  Bug Girl has a great explanation of homology and summary of the article if you’re looking for more.

Live fast, die young

It is finally starting to feel like summer.  The sun is shining, the weather is heating up, and the humidity is not that bad yet.  It’s a glorious Sunday for a graduation BBQ and a good way to celebrate Memorial Day Weekend.  I’ve been sleeping with the windows open the past few days, and while I’ve been waking up to the birds singing, I haven’t heard many of the crickets.  Soon though, they will come.  The evening chorus will ring on and on in celebration of summer.

Like summer, crickets can’t go on forever.  But new research indicates that crickets who live fast, die young.  The resting metabolism of crickets determined their longevity.  Calling crickets expend energy, which perhaps takes away from their overall energy budget for other activities.  The research team suggests this may have an impact on their overall lifespan.

The results found that crickets with a higher resting metabolic rate have lower life expectancy.  However, the link between mating calls and resting metabolic rate was not fully distinguished.  While links between physiology and behavior have not been thoroughly explored, they are likely to be very important.

Read more about the article on Wired or for the full article, click here.

Mite-y Cheese

Here’s a road I never thought I’d go down: using arthropods to flavor cheese….WHAT?!  Most excellent.

Photo Courtesy of Cabot Cheese

Last night I went to the Science Cabaret with a friend to learn about the art and science of cheesemaking.  There was chemistry, food science, tasting, and to my surprise, entomology as well!

Enter: cheese mites.  At first I was wondering if they were just referring to unknown creatures as “mites” but indeed, cheese mites are truly mites in the subclass Acari.  Often times, these cheese mites are considered a pest of stored food (maybe in this case aged food) if their arrival is unexpected.  The best way to deal with mite pests is to vacuum the cheese to remove mites (no joke) and make sure to keep the aging shelves clean to prevent mites from recolonizing.

But sometimes, cheese mites are good.  Really.  In fact, cheese makers will purposely introduce mites as part of the maturing process to flavor the cheese and get a good rind.  A study published recently identified two important cheese mites: Acarus siro on Mimolette cheese and Tyrolichus casei on Milbenkase cheese.  These two styles of cheese are specialty cheeses from France and Germany, respectively.  Section a in the figure below illustrates a mite specimen of A. siro. b, c, and d illustrate identifying morphological characteristics of cheese mites.

Photo courtesy of Journal of Dairy Science

There are a few other arthropods associated with cheese making, including cheese flies in the family Piophilidae. These flies are not specific to cheese and may be pests of cured meats or cause intestinal damage in humans.  But the intentional introduction of maggots to pecorino cheese yields the Italian delicacy casu marzu.  See Gordon Ramsey’s segment below.

Mmm cheese.  Even Mental Floss is blogging about it.  And Tina Fey.  Better get working on my night cheese.

Stink bug invasion

They’re coming. In fact, in places south of Ithaca they’re already here.  Yep.  They’re stink bugs.

Brown Marmorated Stink Bug

The Brown Marmorated Stink Bug (Halyomorpha halys, family Pentatomidae) is an introduced pest from Asia and has become a major pest of fruit and vegetable crops.  In Pennsylvania, where the pest is believed to have been introduced, the apple and peach crops have suffered major losses.  It’s really too bad if you want to make peach jam scones.

Appropriately named, stink bugs stink when you squish them.  This is due to a chemical defense against predation.  Imagine how that smell would taste…  These bugs feed directly on fruit causing a type of damage known as catfacing.  It’s spotty damage that renders fruit unmarketable.  If these apples were growing on my tree, I’d probably just cut out the damaged parts and make applesauce or apple galette.

While stink bugs cause economic loss in the agricultural sector, most people encounter them in their homes.  They often get in through cracks or open patio doors on a sunny day.  I was in Pittsburgh last week, and stink bugs flew around the living room like nobody’s business.  Not so fun when you’re Wii bowling and one flies into the side of your head at an alarming speed.

The brown marmorated stink bug is particularly pesky, and some other stink bugs in the family Pentatomidae are pests as well.  But not all!  There are, in fact, some beneficial species that are predators of caterpillar pests.  Like this guy!

Spined soldier bug

Frankenfoods

There has been and continues to be a lot of discussion regarding genetically modified organisms (GMOs) or genetic engineering (GE).  While there are many things that fall under this category, I’m going to stick to food crops (which is an expansive category in itself).

This is what I’m not interested in.

Although it looks pretty cool, and might entice children who are picky eaters to try something nutritious, I find the blue hue of strawberries completely unnecessary and unnatural.  It looks radioactive and reminds me of Teenage Mutant Ninja Turtles. (Speaking of which, who thought it was a good idea to let kids pal around with teenaged mutant turtles who were ninjas and took orders from a sewer rat?  That said, I loved that cartoon.)

What intrigues me is the possibility of using genetic engineering to reduce the use of pesticides, reduce environmental impact, and help create a more sustainable agricultural system for the future.  The blue strawberry above is an example of one kind of genetically engineering a transgenic crop.  An arctic flounder gene coding for an antifreeze protein was introduced to strawberry to help protect the crop against frost.  In theory, it seems like a pretty good idea to protect crops.  But I’m curious to hear the reasoning for using a fish protein in contrast to a cold-hardy plant from the tundra regions of the world.

Another hot commodity in the Frankenfoods debate is Bt corn.  Bacillus thuringiensis is a bacteria currently used in organic agriculture as an insecticide for particular crops.  Different strains of Bt are effective against different kinds of pests which means not all pests are susceptible to the insecticide.  The bacteria produces proteins which disrupt the gut membrane of insects, causing pests to stop feeding.  Currently, Bt has been genetically engineered into certain field crops like corn, soy, and potatoes.  Instead of the pest coming into contact naturally with the bacteria, the plant continuously produces the protein toxic to insects.  This dramatically reduces the insecticides necessary to control pests, as is the case with Bt corn and the European Corn Borer.  But it’s important to keep in mind that all the concerns about insecticide resistance and resistance management still exists for Bt crops.

Photo courtesy of Iowa State Entomology

Genetic engineering is not a cure or a method.  It’s merely a tool that might assist with production and the promotion of sustainable agriculture.  It is equally important that we proceed with caution and concern for social and cultural values.  It’s a complex issue that has no singular answer.  And that seems to be my answer for everything.

For more information, Harvest of Fear was a televised report by NOVA and Frontline exploring this issue.  The report can be viewed on YouTube by clicking here.  The Future of Food was a documentary on the same issue produced by Deborah Koons Garcia.

Latex lovers

So the title of this post is a little misleading I have to admit.  I wouldn’t say these insects particularly love latex, but the words tolerate and sequester come to mind.  With the alternatives being avoid, succumb to, die from…not the most pleasant options.

In the title, I’m referring to the common milkweed plant Asclepias syriaca and its associated herbivores. What a group they are!

Photo courtesy of Folks Butterfly Farm

Milkweed is particularly known for its chemical defenses against herbivory, producing latex and cardenolides for protection.  Usually, these compounds are toxic to insect herbivores.  But, as always in the insect world, there are exceptions.  A handful of insects are specialists on milkweed, feeding on one or a few species because they have evolved a mechanism to overcome the plant defense.  For a full list of specialist herbivores, see here.  The most common milkweed associated insects I see around here include monarch butterflies, the common milkweed beetle, and the small milkweed bug.  But I haven’t been looking very closely.

Photo courtesy of Rhode Island Bugs

Notice the striking color of the beetle, bug, and butterfly.  Their bright coloration is known as aposematic coloration, or warning coloring.  They’re telling predators, “I’m not very good to eat.”  Monarchs, in particular, sequester the toxic cardenolides as caterpillars and butterflies.  The result?  Birds spew their last meal.

The thing I’d like to introduce is the amazing monarch migration across North America.  These butterflies overwinter in lower latitudes as adults, congregating in Monterey, California and Michoacán, Mexico.  Given that we just had (hopefully the last) snow in Ithaca, maybe I should go to Mexico too!

Photo courtesy of Wanderlust Images

For more about this awesome migration and ways to tag and get involved, see here.