Liberal Arts Blog — Aposematic, Deimatic, Nyctinastic — Isn’t Evolution Awesome?
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Liberal Arts Blog — Wednesday is the Joy of Science, Engineering, and Technology Day
Today’s Topic — Aposematic, Deimatic, Nyctinastic — Isn’t Evolution Awesome?
I learned three new words this week. What do they mean? Nyctinastic is the characteristic of some plants (such as the “rose of sharon”) to “sleep” (close up at night). Aposematism is “the use of a signal and especially a visual signal of conspicuous markings or bright colors by an animal to warn predators that it is toxic or distasteful.” Deimatic behavior is basically bluffing by species who lack strong defenses. What is your favorite example of each? Experts — please chime in. Experts — please chime in. Correct, elaborate, elucidate.
APOSEMATISM — Skunks, Badgers, Lady Bugs, Poisonous Frogs, Monarch Butterflies
1. The granular poison frog (above) lives in Costa Rica and Panama. Its scientific name is Oophaga granulifera.
2. The skunk (mephitis mephitis) is the reason for this post. I saw one poking in my backyard early last Sunday morning. Initially I thought it was two animals — one black and one white.
3. A lady bug’s bright spots are “warnings” to potential predators of toxic alkaloids.
NB: “Mullerian mimicry is a natural phenomenon in which two or more well-defended species, often foul-tasting and sharing common predators have come to mimic each other’s honest warning signals to their mutual benefit.” An example would be the Monarch and Viceroy butterflies. (See fourth link below.)
DEIMATIC BEHAVIOR — bluffing (moths, butterflies, octopus, squids)
1. The moth above resembles the face of a snake.
2. “The term deimatic or dymantic originates from the Greek δειματόω (deimatóo), meaning “to frighten”.
3. “An experiment by the Australian zoologist A. D. Blest demonstrated that the more an eyespot resembled a real vertebrate eye in both color and pattern, the more effective it was in scaring off insectivorous birds.”
NB: “In another experiment using peacock butterflies, Blest showed that when the conspicuous eyespots had been rubbed off, insectivorous birds (yellow buntings) were much less effectively frightened off, and therefore both the sudden appearance of color, and the actual eyespot pattern, contribute to the effectiveness of the deimatic display.”
NYCTINASTY — “sleeping” in response to diurnal temperature and light changes
1. Darwin described this phenomenon in one of his last books: The Power of Movement in Plants (1880). See the illustration above.
2. Both the petals of flowers and the leaves of legumes can display this relatively rare trait. Examples: tulips, rose of sharon, morning glory, peas and beans.
3. A smaller surface area leads to “better temperature retention and also reduces nighttime herbivory.”
NB: “The earliest recorded observation of this behavior in plants dates back to 324 BC when Androsthenes of Thasos, a companion to Alexander the Great, noted the opening and closing of tamarind tree leaves from day to night.”
FINAL QUESTION
What human behavior can be described, by extension, as aposematic, deimatic, or nyctinastic?
A ladybug’s bright colors advertise toxic chemical defenses
Deimatic behaviour — Wikipedia
A LINK TO THE LAST FOUR YEARS OF POSTS ORGANIZED BY THEME:
PDF with headlines — Google Drive
ATTACHMENT BELOWS -
#1 A graphic guide to justice (9 metaphors on one page).
#2 “39 Songs, Prayers, and Poems: the Keys to the Hearts of Seven Billion People” — Adams House Senior Common Room Presentation, 11/17/20
YOUR TURN
Please share the coolest thing you learned this week related to science, engineering, or technology. Or, even better, the coolest or most important thing you learned in your life related to science and engineering.
This is your chance to make someone else’s day. Or to cement in your mind something that you might otherwise forget. Or to think more deeply about something dear to your heart. Continuity is key to depth of thought.
