Sticks and Scales

Eyes on the tops of their heads

  Evenings at  Urosaurus Utopia  are often spent learning about popular culture and American politics via the medium of television.  When the mind is no longer entertained by the flashing box we shut it down and lumber into our sleeping chamber to make the final preparations for bed.  Teeth are scrubbed, bladders are emptied, clothing is shed, and the harsh ceiling light is replaced with the soft glow of bedside reading lamps, ready to serve as our last source of light before our entry into dark dreamland.  One night, as I clicked on the lamp made to resemble a kerosene mantle lamp, I noticed the wobbly flight of a crane fly (family Tipulidae).

The fly found the lamplight irresistable and repeatedly crashed and bumped against the ceramic base until it decided to take a rest on the wall and meticulously clean every part of its body, not too unlike the ways of a cat.  I watched as it repeatedly drew its front legs over its head and down the entire length of its antennae, no doubt removing some microscopic bits of debris.  The wings were given a thorough shaking and dusting off, just as a bird ruffles and vibrates its feathers.  Each leg was combed and smoothed over by the others in turn and when the fly had quite finished his grooming I'd say I detected a hint of pride in his polish. 

When I zoomed in on the fly with my camera, I was certainly surprised to see the ring of eyes on top of its head, otherwise known as ocelli.  I had no idea that insects had more than the typical two compound eyes.  Turns out that not all insects have them, and the ones that do are flying insects, like dragonflies, wasps, locusts, and flies.  Ocelli, don't tend to be very big, as illustrated in the picture below of the ocelli of a house fly, courtesy of Charles Krebs' Macro & Micro site.      

Part of the reason that ocelli are so small is that they are more photo-receptors than eyes, helping the insects to maintain balance in flight as the simple eyes send information to the brain regarding position in relation to sunlight (or moonlight).  Studies on dragonflies have hinted that ocelli can perceive motion as well, improving insects' ability to evade predators or ambush prey.  My crane fly had such large ocelli (relative to the fly) no doubt because it is a nocturnal species.

Interestingly, lizards also have an eye on the tops of their heads, called the parietal eye, that is photosensitive, associated with the pineal gland and thought to regulate circadian rhythms and aid in hormone production for thermoregulation. 

Common Green Lacewing (Chrysoperla rufilabris)

  While on the subject of beautiful green insects attracted to porchlights, lets learn about the lacewing, courtesy Wikipedia.  Lacewings are members of the Chrysopidae family in the order Neuroptera.  The neuropterans are the lace-wing insects and they first appeared on this earth in the Permian period, about 250 million years ago.  That is pretty old, considering that it would be another 100 million years before skinks (my reference point for evolution) came around. 

Apparently they can hear fairly well with their ears that are located at the base of their wings.  They sing to each other in courtship by vibrating either their bodies or objects upon which they are resting.  Their courtship songs are elaborate enough that they have become species barriers among populations of lacewings that are identical in all ways except the language of their song.

The common green lacewing is fairly populous across North America, much to the delight of gardeners in the know.  The larva baby of the lacewing is called an aphidlion for its voracious dietary preference.  They also eat whiteflies and pesty caterpillars (not sure how they discriminate between pest and non-pest...)  Momma lacewing lays her stalked eggs on a plant with a healthy aphid population.  The hatchlings' senses are limited and they just stomp around crazily waving their giant mandibles in the air until they brush against a fat lazy aphid.  Then they snatch it in their jaws and inject poison into it, which can dissolve the inside of the aphid in as little as 90 seconds, turning it into a jelly donut for the aphidlion.  Down the hatch and it's on to the next bumbling aphid. 

Adult lacewings feed on nectar and pollen and especially like sunflowers, dill, angelica, cosmos, and dandelion.

Emerald Geometer Moth

 

Now that I know geometer moths (their form gives them away) I am noticing the different varieties, all gorgeous.  I am so proud to say (with a British accent for authority), "Ah, yes, my absolute favorite moth family is, of course, the Geometridae... quite."

Carnage on the Miniscule

 

I think I know why spiders are associated with Halloween and autumn.  The summer season seems to really belong to the plant-eating bugs, such as grasshoppers.  They just munch their way through all that lavish growth on the annual plants.  As fall sets in and the temperatures fall, the plant-eating bugs die off or go dormant and all the spiders that were feasting on them suddenly become more noticeable and obvious. 

Toward the end of summer I noticed this garden spider who set up her dwelling in the dried flower stalks of my lemon basil.  She wrapped silk around a good set of them and gathered them together in a cone shape, perhaps to repel water and debris.  In the center of the cone surrounded by a tangle of webbing is a buttery yellow cocoon, now empty.  The spiderlings hatched out early October, pale white versions of herself, no bigger than her toe.  Surprisingly, she did not abandon the web once her offspring had tramped out into the world, deciding instead that the abode was a fine place to watch the world go by.  She has laid traps all around the fresh flowers on the basil, capturing anything that chances along. 

One day I was out checking on my seedlings and pulling weeds.  As I pull weeds my mind gets drawn into the lives of the plants and I find myself on my hands and knees peering into the tangle of growth.  The spider has become a staple of my garden story.  I check on her just like I check on my seedlings.  This day, as I bent down to spy on her I noticed the struggling bee, defiantly alive, fluttering her wings helplessly.  I was happy to see the bee, because it meant that there were bees around.  I am so used to thinking that bees are declining that seeing them in my yard is always a surprise and a delight.  I scoped out the yard and discovered Erik's Dalea bushes positively vibrating with bees.  The Dalea was the neon OPEN sign bringing them into the yard and then they casually had a look around, discovering the lemon basil and tomato plant.  This spider is directly enjoying the fruits of the Dalea's florabundance.  Interestingly, the food chain doesn't end there, as you can see there are little flies (I count at least seven) lighted upon the bee's body.  What are they doing?  I think they are eating something.  Or maybe getting ready to lay eggs upon the corpse.  What do you think?

Not JUST a Theridiid spider

She is the dreaded widow, Lactrodectus hesperus.  I found out that she is wearing the colors of an immature female.  This makes the story even more intriguing, as the question arises, can immature females mate and have egg sacs or was this spider babysitting for her mother/sister/aunt?

It also makes me wonder whether I need to worry about black widow spiders plaguing Urosaurus Utopia!  Around the same time that I saw this one, I saw one under my dad's shed and one behind the garbage cans.  I am overly protective of the lives of animals, but both books I consulted, Insects of the Southwest by Floyd Werner and Carl Olson and Venomous Animals of Arizona by Robert L. Smith, advocated dispatching the lives of these unblessed creatures.

I did learn some interesting facts about them.  First, our black widows are not "true" black widows, those would be Lactrodectus mactans, the eastern species.  (P'shaw, I say, perhaps ours are true and theirs is the imposter!)  The female will go to great lengths to avoid biting; she will only do it if she is trapped by a body part or mistakes a finger dangling in her web as prey.  She catches her prey when she feels the vibrations on her web.  When the wandering males discover a female, usually by the pheromones on her web, he sends specific coded vibrations to her to advertise his presence.  If she stays completely still she is communicating her willingness to receive the nuptual gift of a sperm packet, which he places in her fanny pack.  He then hangs around practically begging her to perform the grisly act because his body contributes guaranteed nutrients to his eggs.

My own geometer moth

 

A couple of days after posting about geometer moths I saw my own geometer moth, which I am convinced is the mother coming to scowl at me after I offered her offspring as larder to the ant colonies.  It's interesting to note all the color varieties within these moths.

Theridiid spider

 

I finally got around to pulling the last of the summer weeds, mostly red spiderling and spurge.  The weeds had climbed up in and around anything in their paths, including the unused wheelbarrow leaning against the cinderblock wall separating Urosaurus Utopia (the name I gave our house) from Green Pool Acres (next door neighbor).  I moved the wheelbarrow from its resting spot in order to gain access to the weeds clamboring about when I spotted these twin egg sacs and their parent.  Her body is so similar to a black widow's, but you can see for yourself that she is not one.  I remained cautious, nevertheless.  My guess is that she is in the same family of spiders--the comb-footed, cobweb, or tangle-web spiders.  As I clicked away with the macro setting on she patrolled up and down, always returning to her sacs.  It certainly was a surprise to see two sacs, I thought one was typical.  There are 160 species of spiders in Arizona, ten of which are Theridiidae.

It's Getting Buggy- Conclusion

On Thursday I checked the eggs and noticed that they weren't eggs anymore, they were moving threads.

 

They were extremely tiny.  This detail was invisible to the naked eye.  They were about 2-3 mm long and 0.5 mm thick.  Their locomotion was immediately discernable.  They moved in the classic "inchworm" style.  In the next photo, not only can you see one hatching from it's egg, but you can also see the classic inchworm locomotion in the upper right corner.

 

It turns out that all "inchworms" are larvae of geometer moths--moths of the Geometridae family--Latin for "Earth-measurer," since they measure it as they inch along.  I really wanted to keep a few to watch the complete cycle, but I had no idea what to feed them, and caterpillars can be plant specialists.  I have since learned that in Tucson some geometers feed on the hop bush, which Erik has planted in our back yard.  Since I didn't know what to feed them, I figured they would have the best chance at life if I put them outside.  I placed the diaper back where I found it on the patio.  A few hours later my mom was hanging out laundry and saw that the ants were carting the hatchlings off one-by-one!  Sigh...  The insects are having their end-of-summer wars right now. 

Now it makes sense that the eggs were geometer moth eggs.  I frequently find adult moths resting on my laundry, especially if I left it on the line over night.  Originally I thought that the eggs were laid on the diaper when it was left on the patio, but now I believe the eggs were already there when I took it off the line, I just didn't notice them.  Here's what adult geometer moths look like:

Turns out there are 26,000 species of geometer moths in the world!  That's over three times as many as all the species of reptiles on the earth!  In just one family of moth!  There are 400 species of geometer moths in Southeastern Arizona and almost 2000 species of all moths.

The white moth pic is from Colin Miller's website and the brown mottled moth is from Robert Behrstock's website.

Horse Lubber

This week's Unplugged Project was "Insect."  There are so many insects in Tucson right now, due to the monsoon rains.  My backyard garden and yard is a grasshopper metropolis, which in turn becomes a grasshopper buffet for spiders, lizards, and birds that visit.  Close to our house is Este Wash, a drainage ditch for Broadway Blvd that feeds into Tanque Verde Wash.  The walls of the wash are all concrete, the bottom is sand and the sides are bordered by backyard fences.  The vegetation that grows in the washes is all pioneer species, i.e. weeds, and plants that have escaped their intended domestic habitations.  There is a lot of prickly pear, mesquite, palo verde, and broom.  On one broom patch we discovered these horse lubber grasshoppers, usually about one per plant.  The broom has new succulent growth and plenty of cover, though the horse lubbers don't worry too much about cover, since they are noxious-tasting to even the most indiscriminate predator.  In order to advertise their disgusting taste, and avoid getting eaten, they display bright orange and yellow pinstripes on their matte black carapace, sort of like a hot-rod. 

Grasshoppers figured prominently in my zoological development.  The summers in Colorado Springs brought many grasshoppers for me to pounce on with great zeal, slowly peeking under my cupped hands to check if I had actually captured the treasure.  Sometimes, the act of peeking gave the captive a holy exit and he leaped for his life.  Other times a peek revealed nothing, as if the creature vanished into the ether, at which my lust for a grasshopper would triple and I would launch into the search with greater fervor.  When I finally managed to scoop up one of my buggy brethren I would place it with reverence into a specially prepared "home"--a jar with grass plucked fresh from the lawn and a stick to rest on.  The holes in the lid were punched with one of my mother's paring knives.  The jar would stay on our front porch for a couple of days, after which the hopper received his freedom.

The horse lubbers are not your garden variety grasshopper.  Not only is their color striking, but their size is startling.  They can grow as big as a cigarette lighter.  We decided to catch one and put it in a jar.  Unfortunately, I have lost much of my childhood bravado and so I employed Erik to catch it in a plastic grocery bag.  We brought it home and set to work creating a temporary home.  A quart-size Mason jar with screen (found in the wash) hot-glued onto the lid become his observation cage.  We provided a sand bottom and some broom for him to sit on.  We also gave him a bit of romaine lettuce as recompense for his time.  In retrospect, we should have dispensed of the broom as it crowded the enclosure--a resting stick would do fine.

While our lubber did appreciate the romaine, we all agreed that he looked pitiful in the jar, like a whale in a fishbowl.  We took him back to his real home two days later.  As I let him out, he seemed a little dazed and confused, but ultimately, no worse for the wear.