Zombie Worms From Planet Sphinx

This time of year, when you're harvesting tomatoes, you often notice part of the plant where the leaves seem to be missing and all that's left are stubby stems.  This is not a deformed tomato plant.  Look closely and you will see a stem that seems to be especially thick and stubby like so: 

Tobacco Horn Worm (Source)

The gigantic worm above is a tobacco horn worm.  It is a positively ravenous caterpillar that literally stuffs itself with tomato or tobacco leaves.  If you touch one, it seems to be so full that its skin feels like a grape leaf around a dolma.  It eats so much of the tomato plant that it can reduce tomato productivity dramatically.  Farmers dislike these caterpillars, but I bet most of them also admire the strangeness of these creatures. 

Tobacco horn worms grow from tiny eggs deposited on tomato plants by the Carolina sphinx moth, a gorgeous night creature that moves and hovers like a hummingbird.  It has a coiled proboscis that it uses to probe nectar from night-blooming flowers trumpet-shaped flowers.  Here is a sphinx moth feeding on an azalea:

Sphinx moth feeding.  (Source)

 Sometimes when you see a tobacco horn worm, it will appear to be covered with dozens of white, ovoid bead-like objects.  When you see this, you know the horn worm is one of the walking dead.  The white things are the pupal cases of a type of braconid wasp, which lays its eggs under the skin of the horn worm.  The eggs hatch inside the horn worm and eat the worm from the inside out.  The larvae begin to burst out of their horn worm and weave little white cases with lids around themselves.  In a few days, they will emerge as adult wasps, and the horn worm will expire as a shrunken husk of itself.  The adult wasps will go on to infect and kill other horn worms.  Braconid wasps are friends of the farmer because they help do the work of dispensing with horn worms.  Anytime a farmer sees an infected horn worm, she lets it be so that more wasps will hatch.  Farmers can even order braconid wasps in the mail to release on their farms.  Here is an infected horn worm:

I know it's hard to see, but there is a parasitised tobacco horn worm in the middle of the picture.  I'll bring a better camera to work tomorrow.

 Here are some better pictures I didn't take from this website:

A good picture of an infected hornworm.

An adult braconid wasp spreading its wings for the first time.

Not All That Buzzes is Black and Gold

The airspace on the farm is busy.  There is no air traffic control, but no one seems to collide.  I'm a giant lumbering along amongst the cloud of busy insects as I work my way down rows of flowers and vegetables.  They hardly seem to notice me as they go about their work.  With so much time and so many insects, I've gotten to know their sounds well.  You can tell an amazing number of buzzing insects by the qualities of their buzzes.

The easiest to recognize are the cicada killer wasps I wrote about a few weeks ago (here).  They have a steady bass tone - a low buzz in which you can occasionally hear individual wing beats.  They are loud and their pitch only changes from the Doppler Effect, lowering a bit as they fly away.

Cicada killer wasp.  Picture source.

Bumblebees are the most common on rows of flowers.  Their buzzing is all fits and starts as they whiz from one flower to the next.  They seem to have trouble steering because they swerve around a flower's entrance before crawling onto it, so their pitch varies widely as they try to align themselves for landing. They are generally loud and low in pitch.

Bumblebee.  Picture source.

Honeybees are quiet and unfortunately rare on the farm.  They move and sound a lot like quiet, higher-pitched bumblebees.  If bumblebees are the bases, honeybees are the tenors.  Sweat bees are the sopranos.  They have these little tiny, quiet buzzes as they try to wedge themselves into the backs of your knees so they can sting you when you squat down.  They are usually unnervingly near you, and they whiz off when you try to swat them.

Sweat bee.  Picture source.

The bugs, stink bugs and assassin bugs, are hilarious once you get used to them.  They buzz so stereotypically that I expect them to have little captions over their heads filled with z's.   They hide amongst the green parts of plants instead of the flowers, and they wait until the last minute to try to escape from a perceived threat.  I'll be harvesting tomatoes and all of a sudden a loud buzzing bug will be flying erratically very near by.  No other buzzing insect buzzes so close and loud. 

 

 

 

Leaf footed bug.  Picture source.

There are some stealth insects too.  Wasps usually don't make a sound.  If you are very quiet, you can hear a little purring noise when they are very close, but usually they just seem to float by noiselessly.

Paper wasp.  Picture source.