Category: spiders

More true facts: ZeFrank on the important of electric fields in nature

December 7, 2025 • 12:00 pm

This eclectic ZeFrank video was sent to me via reader Keith, who notes that ZeFrank is also on an “educational channel” containing videos that have been bowdlerized for educational use. But this one isn’t on it, and I think we’re all adults here. (“Jerry”, referred to several times, must be the producer.)

The first bit is about nematodes (“roundworms”), which inhabit a variety of environments and have a variety of lifestyles, including gross but fascinating parasites.  The discussion of how parasitic nematodes infect insects, using electrostatic charge, is amazing, and the same method is used by ticks and mites. (There’s an ad between 4:22 and 5:38 but it’s for Planet Wild, which has a good mission.)

We then learn that electrostatic fields promote the pollination of flowers by bees. We also see again how bees use thoracic vibration to gather pollen, something that Athayde Tonhasca Júnior wrote about the other day. Finally, we get a lesson on the physics of how hatchling spiders disperse by spinning threads that they release into the atmosphere to drag them away from the hatch site: this is a way of finding a new and possibly better habitat.

As usual, the video is terrific and the science accurate.

 

Readers’ wildlife photos

November 7, 2025 • 8:15 am

I’m running pretty low folks, so if you have good wildlife photos, perhaps you’d like to collect them, write a bit of text, and shoot them my way. Thanks.

Today we have another photo-and-text journey from Athayde Tonhasca Júnior. This is part II, and you can find part I here, which explains the region.  Athayde’s captions are indented, and you can enlarge the photos by clicking on them.

Chapada Diamantina – II

We continue our journey inside Lapa Doce.

There’re lots of water stored in pools, nooks and crevices in all these cave networks. This water was vital to local populations before wells and distribution systems arrived. The doce of Lapa Doce is an allusion to água doce (sweet water), the Portuguese term for ‘fresh water’. These waterbodies are home for all sorts of creatures, including the endemic, blind and albino catfish Rhamdiopsis krugi:

Many skeletons of extinct creatures such as saber-tooth tigers, prehistoric armadillos, horses, and giant sloths have been found on the ancient riverbed. Here, a Eremotherium laurillardi giant sloth is flanked by a 1,80 m human:

The Scream II:

Everywhere: the relentless destructive/constructive action of water:

In some thousand years, this stalactite and stalagmite will come into contact and fuse into a column. You can’t see it from pictures taken by phones under torchlight, but mineral water is dripping ever so slowly from the tip of the stalactite:

The end of the trail, through another collapsed doline. Back to a world of blinding light and sizzling temperatures:

Some of the hundreds of cave paintings found on the walls of collapsed dolines in the region. They have not been dated, we know nothing about the artists, which didn’t stop wackos infesting the internet with extraterrestrial theories:

These cavities under the cave projection look like the result of water drips, but looks are deceiving. Each hole is a trap. A careless insect falling in will try to climb out, dislodging soil particles that send sensory signals to a predator buried on the bottom of the pit– an antlion larva, a lacewing-related insect (family Neuroptera) that will seize the prey, inject it with venom and suck up its innards:

Danger, danger everywhere. An apparently benign bank along the trail…:

… is an ideal ambushing spot for a trapdoor spider (infraorder Mygalomorphae). The door is a hinged segment of a silk cocoon that hides a patient spider:

Readers’ wildlife photos

October 10, 2025 • 8:30 am

Thanks to the four or five readers who sent me photos. Please keep ’em coming in!

Today’s photos come from Rik Gern of Austin, Texas. Rik’s captions are indented, and you can enlarge his photos by clicking on them.

Here’s some randomonium I hope you can use. The unifying theme to these pictures is that they were all taken in my yard within the last six months .

The first picture was taken in May and shows us flowers from a green poinsettia (Euphorbia dentata)  waiting to bud:

This is a spotted bee balm (Monad punctata). It is early in the flowering season, so this one hasn’t developed the tiered layers that give the flowers the look of a wedding cake designed by Dr. Seuss, though it still has a whimsical look:

My yard has several patches of false dayflower (Tinantia anomala), and at first I thought that’s what these were, but the center looks a little different, and I believe this is an Asiatic dayflower (Commelina communis). It doesn’t grow as tall or last as long as the false dayflower.

This plant is a more recent visitor to the yard and iNaturalist identified it as standing cypress (Ipompsis rubra). Online pictures show a plant that has a bright red flower, but I have yet to see this one in bloom, so I may have to wait till next year to be sure, although the leaves look like the pictures I found online. The plants in my yard are still very small, but it looks like they can grow to be quite large, so if the identification is correct, I’ll really have something to look forward to:

(I tried to take a second picture using iNaturalist, but this time the app identified it as Egyptian cypress and then froze up after I took the picture. I couldn’t find any plant called an Egyptian cypress when I did a search, so I’m not sure what’s up with iNaturalist.)

Our final entry is not a plant but a large, scary looking, but harmless zipper spider (Arigope aurantia). I saw the spectacular looking web the other day when I went around the side of the house to put some items in the recycling bin. It was so striking and amazing looking that I thought it would be easy to photograph, but I discovered that spider webs aren’t so easy to get good pictures of.

The spider gets its name from the distinctive zig-zag in the middle of the web. When I first moved to Texas, I was staying with a friend in the country and there were dozens of these spiders and their webs all around. I quickly discovered that the webs are not your typical little spider webs that can be easily brushed away; they are tenacious and sticky and you do not want to brush against one.

Although the spiders eat insects, small birds are vulnerable to getting stuck in the web. On one occasion I awoke to find a poor hummingbird stretched out spread eagle in the web. The spider didn’t take any interest in the bird, but it was a sad sight and gave me a lot of respect for zipper spiders and their webs. This one has taken up residence by the side of the house where there aren’t so many birds and I’m happy to let it stay as long as its web stays out of my face and hair!

The mighty web:

Here is her trademark signature. This one isn’t as dense or distinctive as some, but it still serves to identify the host. I wonder if our spider can spell “some pig”?:

The spider waits patiently:

Extra: Reader James Sulzer wants readers to help him identify this bird:

I took the photo today with my Canon camera at home in my backyard here in Kempton Pennsylvania. It was flying with a flock of turkey vultures that I was trying to photograph with my 400mm lens.
This was the best angle I could get before the birds left the area.

We do get a lot of hawks coming over the house because we are located a few miles from Hawk Mountain Sanctuary. I might contact
someone there who may recognize the type of hawk or eagle this is. Thanks!’

Please put your answers (or guesses) in the comments.

Readers’ wildlife photos

October 2, 2025 • 8:30 am

I have two batches now and some singletons, but of course that won’t last a while, so please send in your wildlife photos. Thanks.

Today we’re featuring the insect and spider photos of reader Mark Sturtevant. Mark’s narrative and captions are indented and you can enlarge his photos by clicking on them.

After a longer than usual absence, I am back with more pictures of arthropods from my area in eastern Michigan. These are pictures from May of not this season, but the previous one. I am far behind in processing pictures as I have so many!

The pictures here will be mostly about moths, starting with a couple of caterpillars. Here is the larva of the Copper Underwing (Amphipyra pyramidoides). Underwing moths are cryptic, but they usually have flashy hind wings as shown in the linked picture to this species. This is a form of deception, since when an underwing moth is flying, a predator would see the bright colors. But after an erratic and hard-to-follow flight, they duck around and land on a vertical surface {usually a tree trunk), fold their wings, and they no longer look like they did.

The next caterpillar is an Eastern Tent Caterpillar (Malacosoma americana). The larvae are very gregarious and together they form a densely webbed bivouac where they shelter for their entire larval stage. They periodically arrive at a quorum for feeding en masse, and when that decision is made, they migrate out together to feed by following pheromone trails to the leaves and then back again to the bivouac. A mature caterpillar will wander on its own to make a cocoon, as I suppose this one was doing. This all seems very interesting to me now, so next summer I am resolved to pay more attention to the habits of these common caterpillars.

I have lately been keeping the porch lights on in order to attract insects I might photograph, and the numbers that are pulled in have been kicked up by a lot with a couple cheap black lights, as the UV from these attracts moderate swarms of insects. So here is a very early and small installment of pictures from the porch.

First is a Bilobed Looper moth, Megalographa biloba, a widely distributed species throughout the Americas. There are several related species that also come to the porchlights and you will see those later.

Next is what is either a Grape Leafroller Moth, Desmia funeralis OR a Grape Leaffolder Moth D. maculalis. Identifying the difference requires a ventral view. The modified antennae identify this one as a male.

The moth in the next picture is the Common Spring Moth, Heliomata cycladata, followed by a lovely little moth called the Pale Beauty, Campaea perlata.

The final moth here is the Baltimore Snout, Hypena baltimoralis.

Other common visitors to the porch lights are large Fishflies. As this was in the Spring, this will be the Spring Fishfly, Chauliodes sp. For scale, it wis about as long as your index finger.

Out in area parks now. Here is a mating pair of Crane Flies, Tipula sp.

One of the American Rose Chafers, Macrodactylus sp. Despite the name, the larvae and adults are fairly broad in their herbivory.

Let’s close with some spiders. A common sight in the woods are these numerous but tiny spiders that use webbing to partially enclose themselves in curled leaves. This is one of the Mesh Web Weavers (Dictynidae). I don’t know how they hunt since I don’t see them with much of a web, but perhaps they go after whatever trips over their weblines in their leaf shelter. There is generally prey in there with them.

It’s always a good idea to inspect leaves, and a curled-up leaf, sewn tightly shut with webbing, is like an Amazon package for Mark. Here, I had opened a tightly enclosed leaf and found this very annoyed crab spider glaring at me inside. What I see here suggests it is a Bark Crab Spider in the genus Xysticus (given the placement of eyes, bristles on the first tibia, and so on). From the looks of her, she will be using this enclosure to protect her egg sac. So after some pictures, I put her and her leaf in a well sheltered area.

The final picture is a favorite species of ground spider, the Parson Spider, Herpyllus ecclesiasticus. These zippy critters commonly turn up in the house. The common name refers to the silvery markings on the abdomen that looks like an old timey minister cravat.

Readers’ wildlife photos and videos

June 14, 2025 • 8:15 am

Here’s a Saturday potpourri of photos and videos from several readers. Their comments are indented, and you can click on the photos to enlarge them.

A video from Jonathan Dore:

I took this video a couple of days ago when I noticed a solitary ant dragging the carcass of a dead wasp across our deck. By the time I got my phone out, it had gone over the edge and was carrying the wasp, while hanging upside down, along the bottom edge of the edging strip of the deck. After going a couple of feet it disappeared behind the edging strip, presumably the entrance point to its nest, or at least the next part of its route. At first I thought the ant was holding onto the wasp with a couple of legs while hanging on to the deck with the other four, but looking closer I believe it’s using all six legs to hang on and is carrying the wasp using only its jaws. Both aspects  —  the leg-hanging and the jaw clasping  —  see like a good illustration of the ant’s remarkable strength.

From Natalie in Berlin, a spider that I identified as a triangle web spider. She was amazed at its laughing-face markings. There is one species found in Europe and North America (Hyptiotes cavatus), but this may be the European spider of the same common name, Hyptiotes paradoxus. She found it while washing lettuce, and let it go.

And a short video of the spider emerging from the lettuce with narration by Natalie:

An insect and some mammals from Christopher Moss. First, the insect:

The white-spotted spruce sawyer (Monochamus-scutellatus), likely a male from the length of the antennae:

From Christopher Moss, “the first muskrat [Ondatra zibethicus] photos of the year”. He adds:

I see he is eating a stand of reeds, and has nearly flattened all of it. Fortunately there are plenty more for him to move on to. 

From Paul T.:

Urban wildlife or near my house.  West side of Madison WI. Just taken with my phone. Sandhill cranes [Antigone canadensis] from last spring, and last month’s wild turkeys [Meleagris gallopavo], with four strutting their stuff, and one outside my window.

. . . And from Cate Plys, a squirrel that’s probably leucistic:

I found it near our place in Michigan where we are now! Sadly it scampered up a tree and I had to take these pics at extreme close up, so the quality could be a lot better.


Readers’ wildlife photos

June 7, 2025 • 8:35 am

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: