Odonata

Damigella
Calopteryx splendens male

The Order Odonata order includes big predator insects like Dragonflies and Damselsflies, which spend the first part of their life in water hunting invertebrates and small fishes while the adults are good flyer who hunt flying insects.

Their nymphs are not very agile in the water, so they stalk and wait for their prey to pass nearby, close enough to be captured with their extendable lower lip called “Labium” which allows them to seize animal quite big as tadpols, small fish and even newborn snakes.

The amazing nymph hunting technique

The adult’s hunting technique is to catch the flying insect using their feet and quickly kill it with the mandibles. The hunting success rate is between 90% and 97% compared to the 20% achieved by cats which are also considered excellent hunters.

How can the dragonflies be so efficient? watch this video and find it out

They have very small antennas and an excellent sight.
The adults rest on roosts, twigs or leaves from which they can keep an eye on their hunting territory from above. They usually hunt in daylight until the early evening after sunset.


The Odonata Order is split in 2 main Infraorders:

  • Anisoptera
  • Zygoptera

Anisoptera are the Dragonflies, they have big composite eyes all around the head without separation, when they are not flying, wings are kept open. The fist wings pair is bigger then the second pair.

Libellula
In this Dragonly, you can notice the very small antenna and the huge bicolour eyes which surround the whole insect’s head.
Picture by Valter Grillo

Zygoptera are the so called Damsels, generally a little smaller then the Dragonflies, they have the eyes on the side of the head quite distant from each other and when they rest, keep the wing closed on their back. Both wings pair have the same size and colour.

Calopteryx spendens male details
Calopteryx spendens male. Here you can see the details of the short antennas, the eyes in the head sides well separated between them and the wings kept in resting position behind his back.

There is also a small Infraorder Anisozygoptera which includes only the Family Epiophlebiidae which has only one genus Epiophlebia. This genus has 4 species between Japan and China
Epiophlebia diana Carle, 2012 China
Epiophlebia sinensis Li & Nel, 2011 China
Epiophlebia laidlawi Tillyard, 1921 Himalaya
Epiophlebia superstes (Selys, 1889) Japan

Want to know more? visit the following sites:

https://en.wikipedia.org/wiki/Odonata
https://en.wikipedia.org/wiki/Damselfly
https://en.wikipedia.org/wiki/Dragonfly
https://en.wikipedia.org/wiki/Epiophlebia

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Shooting the stars

To photograph the stars you do not necessarily need special equipment, very often you just need lenses and cameras even modest and some tricks that I will try to explain.

Cielo stellato
Shot with Nikon D5600, Lens Nikkor 35mm f/1.8 Exposition 8 sec, ISO 3200, Manfrotto Tripod, self-timer 10 seconds.

Recommended gears:

  • Reflex aps-c or full-frame
  • Tripod (sturdy)
  • Shot lens (18mm, 35mm) preferibly with big aperture, below f/4
  • Remoto trigger, in order to avoid unwanted vibrations and shacking the camera while shooting

Optional gears (I won’t discuss it here)

  • OPTIONAL – filter to lower the light pollution
  • OPTIONAL – Night sky tracker

Camera settings:

  • Manual focus (MF) focusing on a single star (ok… I will write an article about it)
  • Use a sturdy tripod
  • Turn off the Image stabilisation (always turn it off then using a tripod)
  • Shoot in selt-timer mode, or using a remote trigger or a digital time remote
  • Turn off the noise reduction for long exposure, very important if you are planning to use stacking software like Deep Sky Stacker o Sequator
  • Use the maximum aperture. It’s best to use lens very fast preferibly below f/4.
    Usually I shoot with a Nikkor 35mm f/1.8 or with Sigma 105mm f/2.8, sometime even with a Tamron 16-300mm at 16mm f/3.5
  • User the shortest focal lenght: wide-angle lenses or short lens to portrait night landscape, take picture of the Milky Way or some constellations. With lens like 105mm you can take excellent picture of Orion nebula
  • ISO 800: if you have a camera with a high sensitive sensor like Nikon D850, you can also go higher with your ISO to 3200 or even 6400, while if you ave an entry level asp-c, you better stay around ISO 800/1800 in order to avoid to get too much noise.
  • Use long exposure time, but try to avoid the startrail (unless you really want that effect)

The Earth spin very quickly and if you use too long exposure time, you might get the startrail effect, rather then a nice spot on focus. We can use shorter or longer exposure time based on the focal lenght we are using.
The exposure time can be calcolated using the 500 rule or
with the more accurate NPF rule.

500 rule

Frédéric Michaud de La Société Astronòmique du Havre created a new system that take into account other parameter as well in order to get a more accurate value.
The formula is quite complicated, but you can easily calucalte online at the following address

NPF rule online calulator

For instance, taking picture with my Nikon D5600, while using a 35mm lens with f/1.8 I can use an exposure time of 9 secondi by using the 500 rule, while if I choose to use the NPF rule I have to shoot using 6,50 seconds.

In order to avoid to access online calulator, there is an excellent App for your smartphone which has those calculators and many other interesting feature, such as the planner, the moon phases, and really a lot of useful tools.
I strongly advise to use it you can donwload it for Android or iOS

Disponibile su Google Play
Scarica

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Maize adaptation across temperate climates was obtained via expression of two florigen genes

Sara Castelletti, Aude Coupel-Ledru, Italo Granato, Carine Palaffre, Llorenç Cabrera-Bosquet, Chiara Tonelli, Stéphane D. Nicolas, François Tardieu, Claude Welcker, Lucio Conti

Abstract

Expansion of the maize growing area was central for food security in temperate regions. In addition to the suppression of the short-day requirement for floral induction, it required breeding for a large range of flowering time that compensates the effect of South-North gradients of temperatures. Here we show the role of a novel florigen gene, ZCN12, in the latter adaptation in cooperation with ZCN8. Strong eQTLs of ZCN8 and ZCN12, measured in 327 maize lines, accounted for most of the genetic variance of flowering time in platform and field experiments. ZCN12 had a strong effect on flowering time of transgenic Arabidopsis thaliana plants; a path analysis showed that it directly affected maize flowering time together with ZCN8. The allelic composition at ZCN QTLs showed clear signs of selection by breeders. This suggests that florigens played a central role in ensuring a large range of flowering time, necessary for adaptation to temperate areas.

Continue to read the full article on Plos Genetics