Monday, July 30, 2012

Strange Buzzing Bugs of Summer

All last summer I kept hearing a strange buzzing coming from up in the trees in the backyard, and there were creepy looking bug molts showing up on the outer walls and cinder blocks throughout my gardens. I wondered if a new resident was making its home in my backyard zoo.  Then one day last July, I found my cats’ attention riveted to some frantic, buzzing movement on the patio floor.  It looked like a huge fly—like a horsefly, but bigger.  I ran to grab a jar to save it from kitty’s prey-play then took a good look at what I caught.  It didn’t look like a horsefly at all.  It had big, black bulging eyes, thick, finely veined orange wings, and an orange armored underside.  I had to know what it was.

I drove to the Effie Yaw Nature Center in Carmichael (http://www.sacnaturecenter.net/) with my strange bug to see if I could get some kind of identification.  Unfortunately, the center was closed that day; but just as I was about to leave, one of the staff came out and took a look in the jar, then went back to get a field guide for local insects.  With just a few flips through the colored pictures, she stopped at a page and pointed to a picture that looked very much like the creature in the jar—a cicada! 

With some confusion, I said, “It can’t be a cicada; they’re only on the east coast.” But as we read the description I found that there are “annual” cicadas that can be found on the west coast and throughout North America and Canada.  So, after dropping the still living cicada in a bush near the center as the staff member suggested, I went home somewhat the wiser.

But my introduction to cicadas did not end there.  Just a few days later I was mowing over a large pile of dried leaves in my back yard when I looked down and saw—to my great surprise—a cicada clinging to the front of my shirt.  After my initial shock, and impulse to shake the bug off me, I decided to capture it for some photographs and start researching these strange new inhabitants of my backyard.

The cicada seemed pretty docile, so I put it in a shallow, white pan and started taking pictures.  It even stayed on its’ back for a short time so I got a pretty good photo of the stomach.  Then, after letting the cicada fly free, I turned to the Internet to learn more.  And that’s where the search almost ended.  Information on cicada’s in California is almost non-existent except for the “Bulletin of the California Insect Survey” published by UC Berkeley in 1954.   http://essig.berkeley.edu/documents/cis/cis02_3.pdf

I checked for updates with the Essig Museum of Entomology at UC Berkeley, and the Bohart Museum of Entomology at UC Davis, and the Entomology Museum at UC Riverside, and found little to nothing about cicadas in California.  So I turned back to the Internet, and after extensive searches found enough information to narrow down my “little bug” to the genus Okanagana, based on the circular markings on its back.  There were three species previously found in Northern California that were possibilities: bella, occidentalis or rimosa.

Now I had something to go on, so I decided to turn to facebook where I found Cicada Mania!  I posted my photos on July 20, 2011 and they confirmed it to be Okanagana rimosa, stating that O. bella doesn’t have as much orange on its pronotum (the shield-like area behind the head).  And O.occidentalis is closer to yellow or white in color, not orange.  Cicada Mania’s website (http://www.cicadamania.com/cicadas/) has more pictures of O. rimosa posted from around the US.

I also found Massachusetts Cicadas during my earlier research, a cicada specialist in New England that has extensive coverage on all cicadas from around the country.  They keep a website for ongoing cicada sightings all over the US. (http://www.masscic.org/sightings/cicadas/okanagana-cicada-in-sacramento-ca)

When I posted my pictures and said that I found the cicada on my shirt while mowing, they said it was a female (identified in the photo by the thin black ovipositor located on the underside of the abdomen) that mistook the sound of my lawnmower for a male cicada mating call—a fairly common occurrence among female cicadas.

Massachusetts Cicada also thought my cicada was somewhere between an Okanagana bella and Okanagana rimosa, seeing morphological features that could have narrowed the identification to either species.  But after looking at many specimens of O.bella and O.rimosa in their collection, they’re pretty confident it’s O. rimosa.  My claim to fame is being the first person to post a sighting of Okanagana rimosa in Sacramento.

But why would they settle in my backyard? According to the Entomology Collection at the University of Alberta, Canada, (http://entomology.museums.ualberta.ca/index.html) Okanagana rimosa is an arboreal species that likes to inhabit mixed wood forests, particularly maple trees.  Since we have three mature silver maples between 60-80 feet tall, plus other mature trees, our backyard is perfect habitat.

The adults feed on the trees fluids and the females lay their eggs at the base of small branches.  No economic damage has been reported from these cicadas other than girdling of small branches and twigs from the female’s oviposition punctures. 

The male cicada creates the buzzing sound by means of “timbals” located at the base of the abdomen.  There are strong muscles attached to this organ that produce the vibrations causing the high-pitched buzzing or chattering sounds.  The females are attracted to this mating call (and similar sounds, like lawnmowers) and after courtship, lay their eggs in the tree.  Incubation records are lacking except for a few reports of up to 90 days or less. 

 



After hatching, the nymphs drop to the ground and burrow into the soil at the base of the tree where they feed on the roots until emergence in late spring the following year.  The mature nymphs then climb onto a vertical surface where they molt into winged adults. 







 
These molted skins are usually found on hard surfaces like stucco, wood or cinderblock, but I was surprised to find one this year on the back of a leaf of my ‘Cherokee Purple’ tomato plant.



Predators of the Okanagana cicada are few, mainly birds and sometimes squirrels.  There are also parasitoid cicada wasps that are attracted to the singing male and on which they will deposit their eggs.



The buzzing is also very attractive to cats, who may find a downed male that is emitting a noisy alarm a fascinating plaything. Our cat, Baby Kitteh, had two newly emerged adults on the garage floor in the first week of June this year, with a third larger adult a couple weeks later.  I do try to take them away from Baby if I can and give them a second chance to carry on their life cycle, but I was too late with these three.


One last thing I found about the cicada:  it does not sting or bite, nor is it poisonous.  They look intimidating but are generally a docile insect that won’t hurt if they land on you.  But it would not be a good idea to let one stay on your arm or a patch of skin for too long, because they may eventually mistake you for a tree branch and try to drive their tough proboscis (a thin feeding tube) into your skin—and that would hurt!

Genus Okanagana

Phylum Arthropoda - Arthropods
Class Insecta - Insects
Order Hemiptera - True Bugs, Cicadas, Hoppers, Aphids and Allies
Suborder Auchenorrhyncha - Free-living Hemipterans
Superfamily Cicadoidea
Family Cicadidae - Cicadas
Subfamily Tettigadinae
Genus Okanagana
Species rimosa - Okanagana rimosa

2 comments:

  1. Thanks for all this info. It was driving me crazy not knowing what was creating the sounds in my Sacramento yard in the summer. Ive yet to actually see one yet though!

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  2. I woke up and opened the restroom door and on landed on me 0.0 i heard a buzzing noise but I thought it was my mind and then it landed on my leg and stayed there for a while it then flew off and landed there again, is this normal and why is it in my restroom? ((I had to smash it on my leg...))

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