Today is Black Friday, a day that marks the beginning of the Christmas shopping season. It's reportedly the busiest shopping day of the year.

But to us, today is Green Friday, in recognition of a female green praying mantis,Stagmomantis limbata.occupying a rib of a tall green cactus in our Vacaville garden. This is not her "busiest shopping day" of the year.

Ms. Mantis is not praying or preying. She is resting. She is clinging to a Pachycereus marginatus, also known as a "Mexican fence post."

She's the last of the season. She's already deposited her egg case, an ootheca, and she's about to expire. 

Ms. Mantis peers at me with her super-duper 3-D vision. She can turn her triangular-shaped head 180 degrees. She's an ambush predator and a strikingly fast predator at that. She can nail a bee, fly or butterfly with her spiked forelegs in about 50 to 70 milliseconds.

But not now.

She is resting. She is the last of the season.

It's Green Friday. 

Human: "It's the end of Daylight Savings Time!"

Praying Mantis: "The end of Daylight Savings Time? Does that mean I have to stop scaring the livin' daylights out of a bee?"

Human: "No, it's when we humans set the clocks forward by one hour in the spring, and then in the fall, we set the clocks back an hour."

Praying Mantis: "So if I catch a bee today at 4 p.m., it's actually 5 p.m."

Human: "Correct."

Praying Mantis: "And if I eat the bee at 4:05, it's actually 5:05 p.m."

Human: "Correct!"

Praying Mantis: "And if I catch another bee at 5:30 p.m., it's actually 6:30 p.m.?"

Human: "Correct again! Go to the head of the class!"

Praying Mantis: "Why do you humans have Daylight Savings Time?"

Human: "To get more daylight in the spring.  Did you know that New Zealand entomologist George Hudson first proposed modern Daylight Savings Time, so that after his work shift, he could get more daylight to collect insects?"

Praying Mantis: "He wanted to collect ME?"

Human: "Yes, and other insects. He won the Hector Memorial Medal in 1923 for proposing Daylight Savings Time."

Praying Mantis: "But still, why would I want to get up an hour earlier in the spring? Honey bees don't leave their colony to forage until it's around 55 degrees."

Human: "Haven't you heard? Early to bed and early to rise makes a MANTIS healthy, wealthy and wise!"

Praying Mantis: "Go away before I mistake you for a bee."

"This hanging potted plant ain't big enough for both of us!"

So, how do you beat the competition? You defeat 'em and then you eat 'em.

That's what Vacaville resident Mike Castro witnessed recently.

The hot spot: A hanging pot of porcelain flowers, aka wax flowers (Hoya carnosa). When the flowers finished blooming in his garden, Castro transferred the hanging pot to his patio.

Castro soon observed a female and a male mantis "getting busy" (mating) on the hanging rope, but the male did not lose his head.

Several days later, he saw two females battling one another. The victorious female promptly decapitated her victim and then proceeded to eat her--everything but the wings and legs.

We showed Castro's images to praying mantis expert Lohitashwa "Lohit" Garikipati, a 2012 UC Davis entomology graduate who is studying for his master's degree in biology it Towson University, Md., with advisor Christopher Oufiero, with plans to obtain his doctorate.

"What he observed is really cool actually!" Garikipati wrote in an email. It's an example of female territoriality. Often times before it gets to this stage, one female (usually the more defensive individual) will attempt to display or throw bluff strikes to deter the aggressor--in this case it is likely a case of beneficial happenstance for the victor; she has less competition now and made a meal of the competitor. What often happens more typically, though, is that the more territorial individual will simply decapitate or de-arm a competitor,  but will not consume the entire mantis. I've seen it a lot thanks to captive observation--mantises do seem to recognize conspecifics, or at the very least that an insect is a mantis. Some species even have species specific mating displays!

"Such examples of territoriality can be hard to observe in the wild, but this is one such example!" Garikipati noted. "And for adult females later into the year. competition is indeed stiff and everything that can help them survive and lay eggs is a benefit."

The PPB (Potted Plant Battle) brings to mind the 'ol Western movie phrase, "this town ain't big enough for both of us" which appeared in:

• The Virginian (1929): "Trampas: "This world isn't big enough for the both of us!"
• The Western Code (1932): Nick Grindell: "This town ain't big enough for the both of us and I'm going to give you 24 hours to get out. If I see you in Carabinas by this time tomorrow, it's you or me!"
• A song, "This Town Ain't Big Enough for Both of Us," written by Ron Mael and performed by American pop band Sparks, for their studio album Kimono My House (1974).  

Researchers, however, attribute the first recorded usage of the phrase to Emerson Hough's 1926 novel, "The Covered Wagon."  Jack McPherson, a character in his book, proclaims "There ain't room in this here wagon train fer both of us, an' one of us has got to hit the trail." 

Flash back to Vacaville: one female praying mantis did "not hit the trail" when warned--and lost the fight, her head and her body. 

And probably her dignity...Girls will be girls?

Scenario: A female praying mantis, a Stagmomantis limbata, is perched on a daphne.

Pho-tog: "Good morning, Ms. Mantis! How are you today? Hope you're not thinking about catching a bee for breakfast!"

Ms. Mantis: "Oh, no! I would never think of catching a bee! I'm...ahem...allergic to bees. Yes, that's it. I'm ALLERGIC to bees. I'm just...ahem...doing my morning exercises. Gotta stay in shape."

Pho-tog: "Bend and stretch, right? Bend and stretch? No honey bees on the menu?

Ms. Mantis: "Oh, yes, bend and stretch.  My morning exercises! No bees on the menu!" (Then she spots a bee below)

Pho-tog: "Hey, wait, why are dropping down in the daphne?"

Ms. Mantis: "Gotta go do my floor exercises now! Yes, that's it. My floor exercises."