Division of Agriculture and Natural Resources
Division of Agriculture and Natural Resources
Division of Agriculture and Natural Resources
University of California
Division of Agriculture and Natural Resources

A Spider Year

Cruising the avocado orchard, checking out the irrigation system

Then Bang!!!!!!! What hit me?????

A little closer look, after clearing some sticky stuff off my head and hair and face and shirt and still not getting it completely off.

And there's the remainder of a spider web with a spider in the center of it (that brown blob near the top right)

 

And high in the sky there's another spider above my head (that little little dot)

I must have initially hit “signal threads” which alert the spider that I was coming, because just as I took these photos, it had scampered off into hiding in a leaf. I tried to get more close-ups but the spider just did not want to get close. It looked like the an unidentified species of Araneidae family of orb weaver spiders that is common in the Ventura/Santa Barbara area.

They have been common all spring and summer this year. The Year of the Orb Spider, maybe. It's been an unusual year with all the rain and mild weather. They feed on all manner of insects that fly into their webbing – thrips, whiteflies, moths, even hummingbirds have been known to be caught up in orb weaver webbing.

They are usually most active at night and morning, repairing the webbing from the night's catches and other orchard intruders. Their webbing can stretch for several feet between branches, with the web catching portion (where the circular part is most intensive) from 6 – 18 inches.

This year has also seen a flurry of infestation by the Caloptilia avocado leaf roller/miner. Maybe that's why there's been so much more spiders, since there's more food.

https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=48887

Whatever the cause of the increased orb spiders is, it's best to thread your way through the orchard with an outstretched branch, used like the wand of a conductor, acting like you know what you are doing.

A study about orb spiders from 1980 in San Diego is available online:

California Avocado Society 1980 Yearbook 64: 153-186 A Study of Neoscona oaxacensis (Araneae: araneidae) in Commercial Avocado Orchards in San Diego County, California Frank Henry Pascoe Candidate for degree of Master of Science in Biology, San Diego State University, San Diego, California.

https://www.avocadosource.com/cas_yearbooks/cas_64_1980/cas_1980_pg_153-186.pdf

 Image: Lea Boyd, Saticoy, CA 2023

 

Posted on Wednesday, September 13, 2023 at 8:05 AM
Tags: spiders, worms
Focus Area Tags: Agriculture

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