Readers’ wildlife photos

Today our regular Mark Sturtevant weighs in with some spider photos. His captions and IDs are indented, and you can enlarge his photos by clicking on them.

Here are some spider photos. Most were taken early last season—I’m usually about a year behind—but a couple are more recent, shot specifically to fill in a narrative gap for this post.

It is an odd thing that I tend to neglect photographing some of the most commonplace arthropods, and probably the most overlooked of these had been what we call house spiders. These shy cobweb weavers always hide from the slightest disturbance, but after much, much effort I managed to get a focus stack of this one in a staged setting. This is the Triangulate Cobweb Spider, Steatoda triangulosa, and you have probably seen thousands of them.

Next up is a species of Ground Spider, I think Drassyllus sp. Ground spiders are free-roaming and are among the fastest spiders I know when they decide to make a run for it:

The spider shown in the next photo is a Running Crab Spider (Philodromus sp). The term “crab spider” is widely used for spiders in different families, so this is not particularly related to the crab spiders that you might see lurking on flowers:

Here is a small Wolf Spider (Trochosa idunno). She was quite thirsty, so it was easy to get this focus stack of her while she was having a drink.

With the previous picture and subsequent pictures, you can see a significant change in my gear through the reflections in spider eyes. I had used a very popular brand of dual head flash for years, but one that produced twin reflections. Last season I switched to a more traditional single head flash, and you can see that in the reflections of things like spider eyes. I’ve always rolled my own flash diffusers, and this is one of those big conical ones that people tend to favor for single flashes. The black intrusion on the bottom in the eye reflections is the camera lens. One element in this early edition of the new diffuser is the bright spot that you can see in the reflected diffuser face. This of course comes directly from the flash head, and it is an exceedingly common artifact in these types of diffusers. However, I managed to make that pretty much go away with later refinements on the design, and you will see that here and there in later pictures.

Next up are jumping spiders. I begin with my personal favorite which is the Tan Jumping Spider Platycryptus undatus. These are the largest species in this family in my area, and I am very lucky that I can go out to my shed and almost always find at least one of these spiders on it. They have a flatter shape than other jumping spiders, and this allows them to quickly hide in cracks. The cryptic coloration of this species would make it nearly impossible to spot on tree bark, but these seem to prefer the shed (as far as I know). Jumping spiders are fun to work with since they have so much personality and even curiosity, but they also can hop away and go scurrying across the dining room table in an instant. The first pictures show a male:

 

In spider-world, males are often more colorful than the females, and this is a product of intersexual selection where males actively court sharp-eyed and judgmental females. Normally, male color displays are to attract a female and to persuade her into mating. But in the world of jumping spiders male color may also be used as a defense against a murderous attack from a female. Jumping spiders have good but also very weird vision, in which red objects appear closer than they really are. It has not escaped notice that the males of many jumping spider species have reddish markings on their face, like this one, and there is speculation that this might cause a hungry female to lunge inaccurately.

The next two pictures are of a female Platycryptus. I always think of them as looking a bit like scary little Ewoks from Star Wars. Unlike the male, who was super chill for pictures, she needed a meal to sit still for her manually focus stacked pictures:

I would like to explain focus stacking. Macro photography tends to produce pictures with a very shallow depth of focus. One solution for this is to take a series of shots at slightly different focal points, while striving to keep the same alignment on the subject. The pictures are combined, and software is used to blend the pictures together to produce greater depth of focus in a single picture. The process can also result in certain artifacts, however, and those are later cleaned up to some degree with digital trickery. The whole process is technically very easy, but it can take time.

The final images are manual focus stacks of Bold Jumping Spiders, Phidippus audax. The first one is a juvenile, and the last two are of a very regal adult male, all decked out to advertise the quality of his genes to females. Those largish chelicerae and fangs may look imposing, but males of all spiders are strictly lovers and not fighters: those things are simply part of his “bling” for the ladies. Their only thought is to meet up with a conspecific spider of the opposite sex and to hopefully not be murdered: