The Zig Zag Dance
Written by Frank Woodard.
I'm fascinated by insect behavior and I enjoy discovering what insects are up to. I try to understand whats going on
with my tiny neighbors. It's not easy. Insects usually don't cooperate! As H. W. Shepheard-Walwyn says in his book
“Nature's Riddles”, often the best I can do is observe isolated moments, incomplete parts of a larger story, and
guess at what is happening.
Consider what might be the mating dance of the Great Black Wasp (Sphex pensylvanicus). One hot afternoon I was
sitting in the shade when I saw two big blue faeries flying back and forth across the meadow. I guess one was
chasing the other. They were at it for quite a while. I tried to “catch” them with my camera but to no avail. Yet at
one point they turned in front of me and flew directly away. The front faerie was flying in a perfectly straight line,
while the faerie following was weaving back and forth to either side at a precise distance behind the leading one
creating a perfect sine wave. Perhaps the following one was trying to impress the leading one with great flying
skills so she would agree to mate. Perhaps... it was impressive to see! It was only later I found one of them perched
on a flower so I could identify it. A second wasp came by several times as if trying to get the perched wasp to play
the chase game. The first wasp wasn't interested and the second soon gave up. Sorry, the best I could do is a blurred
photo of the second wasp tormenting the first wasp.
I hope that at some point when I wasn't nearby observing, as in the following photos of what seems to be a similar
species of hymenoptera, the Potter Wasps (Eumenes fraternus), that the Great Black Wasps might end their dance in
a similar manner. I'm always happy too see more of both on the farm!
Orb weaver spiders are a little easier to observe because they stay in one place. Earlier this season A Zig Zag Spider
(Argiope aurantia) built her web across a garden path through the milkweed. I've had adventures with Argiope
aurantia over the years, thus one of the few Latin names I remember. I know Zig Zag spiders like high perches to
build their webs and I knew if I walked through the web she would move it out of the way. Once I had a Zig Zag
Spider build her web in the open woodshed doorway. She really liked that spot, for after I walked though her web a
couple times she rebuilt her web leaving a Frank shaped space for me to pass through. I also knew as documented
by the Maine Agricultural and Forest Experiment Station Technical Bulletin 190 (2003 by Maloney, Drummond
and Alford) that spiders are a wonderful addition to the garden that help mitigate pests. I made a detour in the path
that went around her web. Soon there were two Zig Zag spiders in that spot and I enjoyed watching them get larger
over the summer.
One day I walked out to the garden after lunch and there was a much smaller spider nearby on Dame Zig Zag's
web. This season I've spotted several different spider webs with two spiders, most often one to the side much
smaller than the one in the center. I'm no scientist but it seems to me that two adult spiders on one web can only
mean one thing. Insects have much more patience that I do and though I kept checking back on Dame Zig Zag I
didn't see any movement and later when I returned to the web the second spider had simply disappeared.
Yet when I returned to Dame Zig Zag's web the next day there was all kinds of activity!The first thing I noticed was
that she had caught herself a treehopper (Ceresa diceros) and was holding it in her mouth. There was not only a
smaller spider on the web about eight inches away above her but also two smaller spiders on the outer edges of the
web. Lets assume the smaller ones were males. At that point the male above began repeatedly approaching her,
stroking her backside for a brief moment, and then quickly retreating eight inches away when she waved her two
back legs at him. During his repeated attempts one of the other spiders approached from her side. The first male
attacked the second male causing the second male to drop off the web, and then the first male returned to his
position. Over the course of about half an hour the first male continued his repeated approaches and then changed
his behavior, now only retreating a few inches away after each approach. The male kept getting more intimate,
beyond just stroking her backside to eventually sidling up beside her a few times. That's when it really got exciting!
About the third time he got beside her she suddenly dropped about six inches and snapped her legs shut just like
closing a trap!! In the photo the male is just a blur between her legs on the left of the photo apparently running for
his life. It seems male spiders aren't into cuddling. A moment later she returned to the center of the web with
something in her mouth. There was no sign of the male! I quickly went around for another view from underneath
but it was only after I reviewed the photos that I saw that at the moment she dropped there was a bright pink spot on
her abdomen, a spot that quickly disappeared a moment later when she returned to the center of the web, reeled
back in her treehopper and had started wrapping her prey. The male had dropped to safety!
The male climbed back up and for a time continued to approach and stroke her back. At one point a male about half
the size of the first male ran up and jumped on her back and then quickly ran away. Obviously the little guy had
high hopes. The first male made a few more approaches and then, once again, the web became quiet. The successful
male was waiting close by on the reverse side of the web and two other males were waiting on the edges. Dame Zig
Zag focused on wrapping her treehopper. Whatever signal she had been putting out had apparently stopped.
Was the dance successful? The next morning she had rebuilt her tattered web and the males were gone. Gone too
was the second Zig Zag spider just leaving behind an empty web. Another of nature's riddles. Before I destroy the
milkweed when I till the garden in the Autumn I'll check for her egg sac. If I find it I'll put it in a safe place in hopes
that next season there will once again be Zig Zag spiders dancing by the garden.
