Golden Silk Spiders, Mating

March 31st, 2011 - 10:09 PM | Filed under Featured Photos | 4 Comments

January 19, 2011 | Armonia Nature Preserve, Limon Province, Costa Rica

When I first spotted this female Nephila clavipes, she was positioned rather low in her web. Her background was cluttered and shaded. I prodded her a few times, and as I’d hoped, she retreated to a higher position in her web where I thought I might be able to get a more pleasing background.

Unexpectedly, her quick movements drew the attention of a male that was also hanging out in her vicinity. I’ve read that males prefer to mate when the female is preoccupied with a meal (so they’re less likely to become a meal themselves). Perhaps he mistook her quick retreat as movement toward prey. At any rate, he wasted no time approaching her and getting into a mating position.

I kept snapping away the whole time. This was the only keeper, which I’m pretty happy with. I took awhile to settle on the right settings that yielded a pleasing background with adequate depth of field. Then I just shot away and hoped some would yield the right plane of focus. I didn’t quite nail it, but it looks pretty good at this resolution.

It was complete luck that this photo shows pretty clearly the tips of the male’s palps, where he stores sperm prior to mating. The tip of one can be seen pointing rearwards. The tip of the other is inserted into the female’s reproductive opening, the epigyne.

Finally, is it just me, or does it seem like the females of this species might just be putting on some sexy lingerie for the males? Just look at the pattern on the underside of her abdomen!

Photo Details:

Canon EOS 60D
Canon EF100 Macro lens
Canon MT-24EX flash
Shutter priority AE, 1/160 sec, ISO 800, f/6.3
Exposure compensation -1 1/3
Flash exposure compensation -1

Subjects: Arachnids, Orb Weavers, and Spiders.
Places: Cahuita to Manzanillo, Costa Rica, Limon Province, and North America.
Behaviors: Mating.
Life Stages: Adult.
Sexes: Female and Male.
Taxa: Class Arachnida, Family Araneidae, and Order Araneae.
Colors: Black, Brown, Silver, and Tan.

4 Responses to “Golden Silk Spiders, Mating”

  1. Nice – I can’t think of another example where the difference in size between male and female is this great.

    Re. photo settings, I’m surprised you even needed flash with ISO at 800 and aperature opened up like that. Also, doesn’t the flash unit FEC setting override that of the camera, or am I confusing this with something else?

    • Troy Bartlett says:

      Extreme sexual dimorphism always brings this to mind:
      Anglerfish

      The background was more brightly lit than the foreground. Her web was on the side of a tree. I was trying to get a well-lit background leaf to provide a nice background. It was too small to cover the whole background, but provided a partial backdrop.

      If there’s FEC on the flash, I’ve never used it. I rely heavily on the camera’s setting for that. I was slightly concerned prior to getting the 60D because they removed a dedicated button for that. It’s still easily accessible, albeit via a different method. The only flash setting I use is the one to balance the output between the two flash heads.

  2. Patrick Coin says:

    Very nice, including the background. This sort of shot is very hard to balance, and I’m not very good at it, but am getting better.
    On the Canons, the FEC is set on the camera, I believe. When you are using E-TTL that takes priority.
    Interesting question about the exposure compensation versus FEC. I think the camera tries to balance natural and flash exposures, and that both those compensations will have an effect.
    Like Troy did here, I usually push the ISO up to brighten the natural-light background–that is because I am usually constrained on the shutter speed and f-stop by hand shake and depth-of-field, respectively.
    With this sort of shot, I sometimes just change flash exposure to manual because the TTL can be inconsistent.
    At any rate, great work.

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