Catharanthus roseus [Madagascar Vinca]

[photoni]

Castellani, Antonio (2022) Catharanthus roseus (L.) G.Don (Apocynaceae) Madagascar Vinca. Photographs made in  visible, ultraviolet and mixed light. LINK

 

Synonyms:

• Vinca rosea L.
• Pervinca rosea (L.) Gaterau
• Lochnera rosea (L.) Rchb. ex Spach
• Ammocallis rosea (L.) Small

 

Other Common Names:

• Madagascar Periwinkle

 

Comment:

Last night I was observing squat and very fast butterflies (hummingbird hawk-moth) insert their proboscis for half a second into the vinca flowers.

 

I was wondering how they can move from one flower to another, in a few tenths of a second, and center the small hole in the flower?

But what will the vision of the butterfly be? Which combination will it be most similar to? TSN575 (~ BG39 3mm) + QB5 (~ BG28)?

 

Embarrassing question ... all the images in the extreme UV that I see here, what's the point ???

 

Thanks for the comments

Antonio

 

Gear:

Sony A7 f.s. with Meritar 50mm lens

Old flash elinchrome 1500W (clare quartz tube)

The last 4 are with Nemo (Alonfire) torch.

 

[colinbm]

Another, Embarrassing question ... is that chewing gum in the left top corner ?

[Stefano]

39 minutes ago, photoni said:

Embarrassing question ... all the images in the extreme UV that I see here, what's the point ???

Curiosity, for me.

[photoni]

1 hour ago, colinbm said:

Another, Embarrassing question ... is that chewing gum in the left top corner ?

@colinbm @Stefano

is a chewing gum covered with Teflon tape XD

[Yves W]

Antonio so no WB on the last photos. Everything is interesting, I like the ZWB3.

For your question, the most frequent of the Sphingidae is Macroglossum stellatarum: 349, 440 and 521nm

Bees go down to 340 and ….324nm.

[photoni]

7 hours ago, Yves W said:

For your question, the most frequent of the Sphingidae is Macroglossum stellatarum: 349, 440 and 521nm

  

@Yves W do you mean, that the Sphingidae have receptors sensitive to these three wavelengths?

therefore it is correct to consider the most flooded vision up to the greens ... and not just blue violet UV

However I do not understand why many flowers are yellow and red if with the vision of the butterflies they are black

 

(photo not mine)

.

 

 

unfortunately the Tangsinuo graph of the UG5 filter is not right, there is a lot of contamination in the reds and IRs

.

 

 

 

 

[Andy Perrin]

Regarding UV-C imaging, for Jonathan he gets more resolution at shorter wavelengths so the photos improve. For others, it’s interesting to see what differences we get from UV-A images. 

[dabateman]

313nm is my favorite by far. The images are sharp and have high contrast, but what you see is similar to 365nm with a lot more work. 

254nm is very different than UVB and UVA. Darker for flowers, but reflective for some leaves. 

Its nice to see differences accross the wavelengths.  I also have to play more with my 970nm and 990nm bandpass filters, that I got from a cheap filter wheel. 

 

@photoni like your photo series across different filters. That is similar  to my choice for various UV wavelengths.  Different lights will also have a nice look. I like my UVB bulb with the Baader venus filter. 

[lukaszgryglicki]

What "UVB bulb" you use?

 

[Yves W]

Yes insects see in UV, blue and green and even some butterflies like Pieridae in red up to 640-660.

They do not see the red so:

- yellow is seen as a green different from the background;

- the red is not seen but they see the reflected UV as for the Papaver;

- purple is seen blue.

[Unscenerie]

Very interesting comparison. I appreciate to see how the QB glass behaves in real world.

ZWB3 seems to be an interesting glass at the intersection of the VIS an UV world.

The lower left flower isn't showing its UV signature with ZWB3, though. Does ZWB3 show UV signatures at all?

I wonder if NIR leakage becomes a problem with ZWB3, though, for people using NIR blockers other than the TSN575.

[dabateman]

The uv signature is green in color when you use zwb3/ ug5/u330.

You can use BG39 or s8612 to block the IR.

I also like it as an IR filter, that gives blue skies and white trees.

[Andrea B.]

But what will the vision of the butterfly be?
which combination will it be most similar to?
TSN575 (~ BG39 3mm) + QB5 (~ BG28)?

 

There is quite a variety of butterfly vision. Here is one reference:  The Eyes and Vision of Butterflies

A few examples from that paper:

• The Japanese Yellow Swallowtail has UV, violet, blue, green, red and broad-band photoreceptors.
• The Painted Lady has UV, blue and green receptors.
• The Golden Birdwing has 9 receptor classes.
• The Common Bluebottle has 15 receptor classes. (wow!)
• The female Small Cabbage White has UV, violet, blue, green, red and deep-red photo receptors.
• The male Small Cabbage White lacks the UV receptor that the female has.

So it is probably rather difficult to know exactly how a butterfly would view the Vinca.

 

It is important to note that some insects have photoreceptors which are not used for color perception, but instead for detecting contrasts or for monitoring motion or position. For example, Adrian Horridge, a neuroscientist who has studied bees extensively, says that honeybees use UV to position themselves for proper flight by noting that the Sun, a big source of UV in honeybee world, is "up". 

 

*******

 One problem when attempting to model insect vision in our photographs for those insects which can detect UV, is that we have no "color" we can assign to reflected UV. My solution to that was to use a pattern to represent reflected UV and combinations of reflected UV with other reflected colors. It's probably a little bit goofy, but I've had fun with it. LINK to Bee Vision Bouquet

 

[Andrea B.]

If a butterfly had tetrachromatic vision [which some butterflies do have] and was able therefore to detect UV, blue, green and red as colors, then the Vinca would look something like this attached emulation.

 

The two Vincas which are primarily UV-absorbing (leftmost and upper right) would appear to this hypothetical butterfly just as they do to us.

 

The three Vincas which are primarily UV-reflecting (on the diagonal) would appear differently to the butterfly than to us because we cannot detect reflected UV. I have illustrated that by adding some dissolved random color dots to those Vincas to represent the reflected UV. The Vinca on the bottom left is only partially UV-reflecting (or alternately, UV-absorbing), so I didn't add as much random color to it.

 

 

 

 

 

---

 

 

However I do not understand why many flowers are yellow and red if with the vision of the butterflies they are black.

 

1) If an insect does not have a red photoreceptor/filter combination which can detect red, that does not mean that the insect cannot see a red flower. The insect knows the red flower is there because it uses other visual and sensory cues in addition to color. (So do humans.) The contrast of the flower against its background, the motion of the edges of the flower in the winds, the scent of the nectar and other cues help guide an insect.

 

2) Not every flower attracts every insect. Pollination is quite specialized. If an insect cannot detect red, then it probably is not a pollinator of red flowers. Hummingbirds often pollinate red tubular flowers. Honeybees are said to prefer violet, blue-violet and blue flower, although we typically see them most any kind of flower.

[dabateman]

26 minutes ago, Andrea B. said:

 

However I do not understand why many flowers are yellow and red if with the vision of the butterflies they are black.

I think its because this world isn't just made up of butterflies. 

Maybe deer or other animals will not eat the flowers and will move on allowing the pollen to be transferred. 

Maybe we humans are too encouraging more color, so flowers will be picked, transported and allowed to pollination over larger distance. 

I think there are many variables at play.

[Yves W]

I don't have too much time to delve deeper into the pollination that I've been passionate about for over 20 years.

For filters, I like the ZWB3 with the TSN575 where UV is seen in green but also with blue and cyan. This is close to the vision of the majority of insects. I also have the ZB1, ZB2, QB29 and QB5.  It is the contrast of the flower and its environment that attracts the insect. The flower contrasts and attracts with its guide nectar (Sprengel 1793).

I agree with Andrea on red flowers which, moreover, in Europe are rare and more frequent in the tropics with hummingbirds.

For Horridge and UV, there have been other studies, Frisch, Daumer and Knoll prove that UV serves in the perception of the flower. It is mainly the ocelli and the upper part of the eyes that are used for tracking even in polarized light.

[photoni]

 

 

19 hours ago, Andrea B. said:

 

• The Japanese Yellow Swallowtail has UV, violet, blue, green, red and broad-band photoreceptors.
• The Painted Lady has UV, blue and green receptors.
• The Golden Birdwing has 9 receptor classes.
• The Common Bluebottle has 15 receptor classes. (wow!)
• The female Small Cabbage White has UV, violet, blue, green, red and deep-red photo receptors.
• The male Small Cabbage White lacks the UV receptor that the female has.

 

@Andrea B. the multispectral vision you say is fantastic and alien

 

if by "bee" vision we mean a phase shift of a color channel, this is the result
UV, blue channel only
VIS, green> red - blue> green

 

(there are movements ... the flowers floated on the water)

 

10 hours ago, Yves W said:

I don't have too much time to delve deeper into the pollination that I've been passionate about for over 20 years.

.

@Yves W time and memory
I often get angry about my low RAM

 

.

 

 

[Yves W]

Photoni, sorry, I didn't explain, I have about twenty books on pollination and hundreds of PDFs. I want to look for studies on the subject and I prefer to wait until winter for the bibliography.

I am 76 years old and for more than 20 years I have been studying orchids full time, their pollination including autogamy. I am inspired by Darwin's work. This morning I got up at 7am.