Readers’ wildlife photos

Keep sending in your photos, folks! Today we’ll finish up with the second installment of Mark Sturtevant’s insect photos (first bit here).  Mark’s notes are indented:

I generally don’t take more pictures of insects after they are well documented in my portfolio, but the jewel wing damselflies are among the exceptions to that informal policy. Besides being very beautiful, I enjoy the challenges that they present. They are shade-loving, which presses me to use the flash, but their metallic colors tend to not come out well with the flash, so I have been trying a variety of experiments to get the right effect. This summer I learned that I can sometimes get a true representation of their colors by bouncing the flash up from the ground or down from the canopy.

This picture shows a female ebony jewel wing (Calopteryx maculata). As one can see they are a bit duller in color [compare to male in previous installment], and they have white stigmata on their wings. When getting pictures of this one I was lying flat on my stomach. After a time she nipped out, grabbed a small moth, and returned to her perch with her meal stuffed into her surprisingly capacious mouth.

6jewelfemale

Next is a very large ladybug larva, probably belonging to the giant fifteen-spotted ladybug (Anatis labiculata). This one was grazing on a colony of leaf beetle larvae. I was a bit surprised to see this since I thought of ladybugs as aphid predators, but they clearly do not care what I think. The leaf beetle larvae seem to be using excrement as camouflage. So, eww.

7ladybuglarva

Next is a longhorn beetle, the elm borer (Saperda tridentata). Although the adults are rather pretty, the larvae can do serious damage to elm trees as they bore extensive galleries under the tree bark.

8longhorn

Nearing the end, the next picture is what certainly looks like a caterpillar but in fact it is the larva of a sawfly wasp, probably in the genus Abia. One difference between sawfly larvae and caterpillars is that the former has abdominal ‘prolegs’ on pretty much every segment of the abdomen, but lepidoptera larvae would have two or more segments without prolegs. Their resemblance to caterpillars is an example of convergent evolution, since like caterpillars they crawl around on leaves and branches, eating the foliage.

9sawflylarva

The final two pictures feature the long-jawed orbweaver, possibly Tetragnatha elongata, or T. versicolor. The color patterns are a bit variable, and it can be difficult to really be sure. In any case, these largish, semi-communal spiders are commonly seen hanging along branches over water. Long-jawed orbweavers look pretty scary with their oversized chelicerae and fangs, but they are handled easily. According to some pictures I have seen, the big chompers are for clasping between males and females.

The first picture is a female, and the second picture shows a male. I had quite a time trying to get the latter picture since he simply would not sit still in the field. I resorted to bringing him home for a staged shot while isolated on a stick in my back yard. But he would have none of it. The male immediately ran up to the top of the stick and posted his abdomen into the air while waving his back legs. I barely had time to realize what he was up to when he suddenly flew away, making a beeline through the air for a nearby tree canopy! The crafty little bugger had sent out an airborne dragline into the breeze, and waited for it to catch onto something before making his get-away along it. I intercepted him just before he was out of reach and returned him to his perch. Seconds later, off he went again! So I had to bring him indoors for pictures where there was no breeze. But even then he was a complete pain in the *ss and the entire process was pretty exhausting. I have developed considerable admiration for this challenging spider, and I would like to return to this group again to try to get pictures that show off their ‘flying’ talent. But since they are good at it, I expect I will need to collect several of them to replace the escapees.

10longjawedfemale

11longjawedmale

 

16 Comments

  1. Debbie Coplan
    Posted December 26, 2016 at 8:21 am | Permalink

    A really wonderful post. I am glad of your success in chasing down the male orbweaver because I love the photo of him at the end.

  2. Randall Schenck
    Posted December 26, 2016 at 8:25 am | Permalink

    Nice photo of the elm tree killer. Small things can do big damage.

  3. Heather Hastie
    Posted December 26, 2016 at 9:05 am | Permalink

    Once again, wonderful photos Mark, and I love your commentary too. Thanks so much for sharing them. 🙂

  4. ThyroidPlanet
    Posted December 26, 2016 at 9:37 am | Permalink

    Nice pics!

  5. Mark Sturtevant
    Posted December 26, 2016 at 10:02 am | Permalink

    Thank you, everybody.

  6. rickflick
    Posted December 26, 2016 at 10:18 am | Permalink

    Following the link for the Jewelwing, I found a head shot that I found fascinating.

    https://en.wikipedia.org/wiki/Ebony_jewelwing#/media/File:Ebony_Jewelwing,_eye,_md,_pg_County_2013-06-11-18.02.19_ZS_PMax_(9022145050).jpg

  7. Jenny Haniver
    Posted December 26, 2016 at 10:36 am | Permalink

    Oh no! Female jewel winged damselflies exhibit the stigmata. Da Lawd sure works in mysterious ways.

    • Mark Sturtevant
      Posted December 26, 2016 at 11:10 am | Permalink

      ‘pterostigma’ is the more secular term. 😉

      • Jenny Haniver
        Posted December 26, 2016 at 2:18 pm | Permalink

        So I Googled “pterostigma” and learned about the aerodynamic function of this structure, which makes me wonder why the male jewel winged damselflies don’t have them. Nonetheless, my mind is polluted by RC associations, which your first characterization triggered. This calls to mind my as yet unanswered question — Why, when an animal is killed for scientific purposes, it’s called a “sacrifice”? Even in its etymology, that term is so laden with religious, specifically Christian symbolism, that I find it impossible to think of the word divorced from its linguistic/religious matrix.

        • Mark Sturtevant
          Posted December 26, 2016 at 4:22 pm | Permalink

          All modern Odonates have the pterostigma, but the female has made it more flashy with the white color. Both sexes patrol near streams, and when at rest they occasionally flick their wings open and closed. This is clearly to signal to each other. I am not sure why females signal like the males do, but I guess their white stigma is to help identify them as female.

          I expect that the term ‘sacrifice’ in science, as in when one kills something for a scientific collection (I used to do quite a lot of that), is done to communicate a sense of gravitas. They are not killed for sport or for personal gain, but to serve a higher purpose which in this case would be to expand knowledge. Even the term ‘higher purpose’ is another example of religion leaking into the language. “Pterostigma” as well, obviously :/ A huge portion of our language idioms are infused with religion since the language evolved in considerably more religious times.

          • Jenny Haniver
            Posted December 27, 2016 at 12:17 am | Permalink

            Your observations are appreciated. I had expected the pterostigma re coloration had some sort of function re sexual signaling, but to find that this structure regulates gliding was quite a surprise.

  8. Posted December 26, 2016 at 11:14 am | Permalink

    Very nice photos with lots of interesting background. I really like your posts.

    • Mark Sturtevant
      Posted December 26, 2016 at 4:25 pm | Permalink

      Thanks, Lou! I only wish I could skulk in a rain forest, as you do. You may spend hours going maybe 20 feet, for the abundance of things to photograph. Here, I have to walk a few miles to get half the material. Still, it is great exercise.

  9. nay
    Posted December 26, 2016 at 11:49 am | Permalink

    Great photos! And the hoops you jumped to get them! And you got a way with words, Dude: “but they clearly do not care what I think.” Hahahahaha – scientific method in a nutshell; you go with the evidence, not the hypothesis. Also” “The leaf beetle larvae seem to be using excrement as camouflage”, but the ladybug larva was not fooled. Many thanks for the pix and the lessons – and thanks to Professor CC(E) for posting them! (Hmmm, lots of “!” in this comment)(but all well deserved!!!).


One Trackback/Pingback

  1. […] via Readers’ wildlife photos — Why Evolution Is True […]

%d bloggers like this: