<< Previous Next >>

Hunter


Hunter
Photo Information
Copyright: Marx Who (Marx44) Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 172 W: 97 N: 926] (3891)
Genre: Animals
Medium: Color
Date Taken: 2010-05-22
Categories: Spiders
Camera: Canon EOS 30 D, Canon EF 100 mm F2.8 Macro USM
Exposure: f/8, 1/160 seconds
More Photo Info: [view]
Photo Version: Original Version
Date Submitted: 2010-05-22 6:37
Viewed: 2288
Points: 12
[Note Guidelines] Photographer's Note
Feeding, digestion and excretion

Uniquely among chelicerates, the final sections of spiders' chelicerae are fangs, and the great majority of spiders can use them to inject venom into prey from venom glands in the roots of the chelicerae.
Like most arachnids including scorpions, spiders have a narrow gut that can only cope with liquid food and spiders have two sets of filters to keep solids out.
They use one of two different systems of external digestion. Some pump digestive enzymes from the midgut into the prey and then suck the liquified tissues of the prey into the gut, eventually leaving behind the empty husk of the prey. Others grind the prey to pulp using the chelicerae and the bases of the pedipalps, while flooding it with enzymes; in these species the chelicerae and the bases of the pedipalps form a preoral cavity that holds the food they are processing.

The stomach in the cephalothorax acts as a pump that sends the food deeper into the digestive system. The mid gut bears many digestive ceca, compartments with no other exit, that extract nutrients from the food; most are in the abdomen, which is dominated by the digestive system, but a few are found in the cephalothorax.

Most spiders convert nitrogenous waste products into uric acid, which can be excreted as a dry material. Malphigian tubules ("little tubes") extract these wastes from the blood in the hemocoel and dump them into the cloacal chamber, from which they are expelled through the anus. Production of uric acid and its removal via Malphigian tubules are a water-conserving feature that has evolved independently in several arthropod lineages that can live far away from water, for example the tubules of insects and arachnids develop from completely different parts of the embryo. However a few primitive spiders, the sub-order Mesothelae and infra-order Mygalomorphae, retain the ancestral arthropod nephridia ("little kidneys"), which use large amounts of water to excrete nitrogenous waste products as ammonia.

marianas has marked this note useful
Only registered TrekNature members may rate photo notes.
Add Critique [Critiquing Guidelines] 
Only registered TrekNature members may write critiques.
Discussions
None
You must be logged in to start a discussion.

Critiques [Translate]

Truly a fantastic capture, both the spider's prey and you as a photographer, Marx! Acceptable dept of field, great sharpness colors and composition!
Regards,
George Veltchev

Hi Mark
What a great shot :a spider and the victim!
Perfect details and colors!
Mariana

  • Great 
  • zetu Gold Star Critiquer/Silver Workshop Editor/Gold Note Writer [C: 967 W: 26 N: 3888] (16941)
  • [2010-05-22 8:04]

Hello Marx
Excellent macro work!
Regards
Razvan

Todo en uno.

Felicitaciones

Hi Marx

An amazing capture, perfect sharpness and details. Excellent composition.

Chris

  • Great 
  • foozi Gold Star Critiquer/Gold Note Writer [C: 2791 W: 0 N: 6696] (25839)
  • [2010-05-23 4:38]

Hello marx,
well captured in excellent clarity and sharpness. The close is magnificent. the effect of seeing it on a stalk of grain is indeed very dramatic.
well presented in splendid intense colour and striking view.

regards,
Foozi

Calibration Check
















0123456789ABCDEF