Regular Mark Sturtevant is back with a batch of lovely arthropod photos. Mark’s captions are indented, and you can enlarge his pictures by clicking on them.
Here are more pictures of arthropods. Some are from area parks, and others are from my house here in Michigan.
First up is an Antlion larva, Brachynemurus abdominalis. One can find the conical pits that these little beasties make all over what I call the Magic Field. How they use their pit to ensnare passing insects is shown in this video. Although they are easily extracted with a spoon to be taken home for pictures, actually getting pictures was not that easy since they generally want to scuttle backwards in an attempt to bury themselves. Right now, I am keeping a few larvae in cups of sand and feeding them ants (which is always entertaining), with the aim of later photographing the pupal stage. Antlion pupae are interesting in that they are still ill-tempered and they bite:
I came upon this wasp-mimicking beetle (Necydalis mellita) along a woodland trail. That it is indeed a beetle is proven by its elytra, even though they are very short. I’ve seen these before but could never get a picture because they are alert and flighty (wasp mimics tend to be wasp mimics all the way). But this one allowed a few pictures. It belongs in the longhorn beetle family:
Next up is a Big Sand Tiger Beetle (Cicindela formosa). These lovely but very alert beetles are common around here in sandy areas. Some days, nothing will get you a picture of one, but on this rather cool and overcast day the task was pretty trivial. Tiger beetles used to be in their own family, but now they have been absorbed into the ground beetle family:
Another challenging beetle is shown next. This is a tumbling flower beetle, Mordella marginata. Tumbling flower beetles belong to their own rather obscure family, and they are normally found on flowers where they eat pollen. There, the least disturbance will cause them to live up to their name as they curl up and fall to the ground:
Next are two grasshoppers because I really like grasshoppers. The first is a ‘hopper nymph of uncertain identity, but it most resembles the Two-striped Grasshopper, Melanoplus bivittatus.
Over the previous summer, I made it a regular habit to scour the front porch in the morning to look for insects that were drawn in overnight by our porch light. Among the more common squatters were these very small Mayflies which I believe to be Callibaetus ferrugineus. First are two females. The close-up picture is focus-stacked with my super macro lens, as are all of the remaining pictures here. She looks pretty strange, as all Mayflies do, but get a load of the male in the next picture.
Here is a male. I still remember my astonishment seeing the first of these! The upward turret-shaped portion of their compound eyes are thought to be used to watch for females:
This set finishes with a couple spiders. First up is a Slender Crab Spider, Tibellus sp. These are shaped to stretch out along grass blades:
And finally, here is a Ground Crab Spider, Xysticus sp. The super macro lens lets me peer into a new world, but I wasn’t expecting that face to look back from it!:
Today sees the return of Robert Lang, physicist, origami master and, today, photographer. Robert’s narration is indented, and you can click on the photos to enlarge them.
More local animals
The Los Angeles basin is a vast urban/suburban metropolis, but its natural boundaries of ocean and mountains are abrupt with sharp transitions created by water and steepness. The northern boundary is formed by the San Gabriel and San Bernardino Mountains (collectively, the Transverse Ranges) and they rise steeply from many back yards along the range. My studio is about 20 feet from the edge of the Angeles National Forest; this gives rise to many wildlife encounters, both at the studio and on the trails that climb up from the back property line. Most of these pictures are fairly recent.
One from last fall that I’ve been saving for RWP is this California Tarantula (Aphonopelma sp.). Probably a male, because he was out and about; in the fall, the males go on walkabout looking for females (who mostly stay hidden in their burrows):
Then we turn to a couple of reptiles. The Western Fence Lizard (Sceloporus occidentalis) is one of the most common lizards around; just walking down the front steps, I’m likely to see one (although it’s rare that they stay still enough to be photographed). They are highly variable in color, and the same lizard can appear either light or dark. In the morning, they are dark to absorb the sun’s rays; then in the afternoon, after they’ve warmed up, they lighten their skin and their lovely iridescence becomes visible:
I was pleased on a recent hike to see a Blainville’s Horned Lizard (Phrynosoma blainvillii) at an elevation of about 4000 feet. They used to be more common in the San Gabriels, but earlier in the previous century their numbers were reduced by collectors gathering them for the curio trade, and they’ve never fully come back. I really should have taken a wide-angle photo of this one; it would have been a great candidate for the “Spot the …” series, as it was so perfectly camouflaged against the sand and gravel I nearly stepped on it:
Another reptile that I’m glad I didn’t step on was this Southern Pacific Rattlesnake (Crotalus oreganus helleri), who was stretched out across the trail. He was pretty chill, though; didn’t budge as we approached, and so we gingerly stepped past. A nice set of rattles on that one!
We have three kinds of squirrels around; ground squirrels, gray squirrels, and the (introduced) Fox Squirrel (Sciurus niger). The local rattlers are happy to dine on any of them.
We also have both crows and ravens; crows are more common down in the neighborhoods, while ravens like this Common Raven (Corvus corax) dominate up in the chapparal. This one is perched on the top of one of last year’s blooms from the Whipple Yucca (Hesperoyucca whipplei):
Larger creatures sometimes come visit the meadow behind the studio. A not infrequent visitor is the coyote (Canis latrans). Although this one was (barely) within the National Forest, they come far down into the adjacent neighborhoods, where they find plentiful food in the form of dropped fruit, loose garbage, and the occasional domestic animal whose owners ill-advisedly allow them to roam free:
Another frequent large visitor is the California Mule Deer (Odocoileus hemionus californicus). This time of year, the bucks are in velvet, like this one. We had a very wet spring, so there is a lot of browse in the mountain canyons and not much to lure them into the meadow, but in the fall, when the acorn crop starts to fall, they’ll be visiting twice a day:
In much of California, the urban/wilderness interface usually exists in one of two states: (1) recovering from the last wildfire; (2) stocking up for the next wildfire. A year ago we had a relatively small wildfire just across the canyon; fortunately, it was a cool day with not much wind, and the fire crews held it to just a few acres:
I spent the afternoon watching the firefighters dragging hoses for hundreds of yards up the ridges while helicopters and fixed-wing aircraft dropped water and fire retardant. I am in awe of the firefighters, who were clambering up cliffs that I wouldn’t even try to scramble under the best of circumstances, while they were wearing and/or carrying 50 pounds of kit and dragging hoses. Within a few hours, they had things under control. The drifting smoke and red fire retardant gave things an almost surreal appearance as they were mopping up:
That was a year ago. One thing about the chaparral is it recovers quickly from fire (indeed, many plants rely on it), and after this spring’s wet rains, the formerly bare ground is covered in new growth, and the burned bushes have resprouted. They’re getting ready for the next fire, which is bound to happen sometime; it’s the nature of this bit of Nature.
A few contributions have been coming in, so we’re good through the weekend, I think. Today we have a new contributor, Małgosia Borkowska-Tarr—from Poland. I’ve also added two photos sent by reader Diana MacPherson from Canada. If you can ID any of the photos, please do so in the comments.
Everyone’s ID and captions are indented, and you can enlarge the photos by clicking on them.
My name is Małgosia and I live in Łuków (eastern Poland) with my husband Brian. He is from California and thanks to him I found out about your website “Why evolution is true.” I took some pictures of wild bees in our garden. There is Anthophora plumipes, Osmia biconis and some others.
From Diana, who found a spider mimicking an ant:
We still have cute spider ants. I took this picture with my 100mm macro lens just now. He’s so small and so convincing as an ant but here he is with his cute spider face.
He’s very tiny – about 2 mm. I took this with a 100mm macro lens so he looks a lot bigger. There are so many species I have no idea what the Latin binomial would be for this guy but he was near my window where I saw the small ant mimicking spiders. I think that window is host to a lot of smaller insects & such that these small arachnids can eat.
And it’s four trilobite species that are the subject of Fortey’s new paper coauthored with Alan D. Gishlick, a geophysical sciences professor at Bloomsburg University, in PNAS, a paper you can read for free by clicking the title below (it’s free with the legal Unpaywall app., the pdf is here, the reference is at bottom, and judicious inquiry might yield a pdf if you can’t see the paper). Trilobites are common fossils, and were marine arthropods that went extinct without leaving descendants.
The upshot is that Gishlick and Fortey analyzed fossils of one species of trilobite found in Morocco, deriving from the Devonian (400 million years ago). This species, Walliserops trifurcatus, had a long trident attached to the front of their bodies, and tried to figure out what it was for. They also found one adult individual whose trident was a bit deformed (see below). Their conclusion is that these were weapons used by males to fight with other males, almost surely to compete for females. They are, posit the authors, the arthropod equivalent of reindeer horns. The other possible functions (feeding, digging, etc.) were largely ruled out.
Here are four species of Walliserops, shown below. All specimens bear a rigid cephalic trident. W. trifurcatus has a slightly recurved trident that bends upwards, while the other species have tridents more flush with the surface of the sediment (all captions come from the paper):
The obvious question is: what is this damn thing for? And there are several hypotheses, all assuming that the structure was molded by natural selection (which includes sexual selection). The authors find evidence against all but one possible function. Here are the alternatives (of course, it could have been used for several things, but it’s likely that selection was wholly or largely on one function). Indented bits are quotes from the paper. The rest of the discussion concerns W. trifurcatus:
A.)Defense. Perhaps the structure could have been used to ward off predators, like the spines found on other trilobites. Here’s how the authors rule this out:
However, such a function would have been difficult given the overall anatomy of the trident and the trilobite. The trident is rigidly attached and cannot be moved independently from the cephalon; it could only be flexed in a dorsal-ventral plane by the trilobite raising and lowering its cephalon. This would create further difficulties since the long genal spines limit how high the head could be angled without lifting the entire body. The trident, therefore, could not be employed in a versatile way, nor be presented as to defend from a predator attacking from above or behind. This morphology is not consistent with a defensive structure.
B.) A feeding structure. Doesn’t seem likely:
A second possible function for the trident would be as an aid to feeding. Like all members of the Phacopida, Walliserops was probably a scavenger/predator, and it might be considered as a possibility that the trident was a comparatively sophisticated sensory device concerned with early detection of prey species—such as buried annelid worms—which could then be grasped by the endopods of the ventral limbs.
C.) Sensory detection of the environment. This is also deemed unlikely from inspection of the structure:
However, examination of the trident in optical and scanning electron microscopy failed to find the arrays of cuticular pits or tubercles usually indicative of the presence of sensilla in fossil arthropods. Most groups of trilobites include species with exterior exoskeletal pitting that is preserved even if the intracuticular canals have been removed by calcite reorganization—and there is no evidence of such exterior pitting on the trident of Walliserops. The absence of evidence for specialized organs on the tines makes it unlikely that it was primarily a sensory apparatus.
D.) A spear to pierce prey: Unlikely because the structure was inflexible, so the animal would have no way of accessing speared prey.
E.) An apparatus to dig, perhaps for prey. The way it’s shaped and angled seems to preclude this (remember, it’s slightly recurved upward; see below):
Another possibility is that the trident may have been used to agitate sediment to disturb prey items, which could then be trapped by the limbs. It is difficult to conceive of W. trifurcatus digging into sediment because to engage sufficiently with the substrate the cephalon would have to tilt at an angle greater than would be allowed by movement on the posterior occipital margin. Equally, if the thorax was arched, the pygidial spines themselves would dig into the sediment.
F.) A combat device on males molded by sexual selection mediated by male-male competition for mates. The authors consider this most likely, especially because the tridents resemble the structure of male dynastine (rhinoceros) beetles, which use them to fight for females.
The authors did a complex morphometric analysis of body and horn shape of W. trifurcatus, comparing it with living rhinoceros beetles to see if the trident could have been used for shoveling/prying, grasping, or fencing—the three types of male-male combat seen in living beetles. The analysis puts the trilobite in the group of living rhinoceros beetles whose males fight by fencing/shoveling: jousting with the structure in front and then trying to shovel the opponent over onto its back. I won’t go into the gory statistical details, which involve principal-components analysis, but the recurved structure of the trilobite’s “trident” is similar to that of shoveling, prying, and fencing beetles (left column: observed means of fighting of living beetles; center: the cephalic structures used; right: the species name [trilobite at the bottom]).
As you see, and as the statistical groupings show, W. trifurcatus is similar to the structures used in rhinoceros beetles for fencing, prying and shoveling. Here is Gishlick and Fortey’s scenario of how the males battled it out in the competition to pass on their genes:
We would hypothesize a fighting scenario in Walliserops similar to that of Trypoxylus. The trilobites would meet and at first spar with their forks, pushing and poking. At some point, they would shift to trying to slide the fork under the other, in an attempt to flip them over. Given the morphology of Walliserops, flipping would be a very effective combat technique. Although the appendages of Walliserops are unknown, it is likely that they were like those of other phacopids in not extending beyond the carapace. This is seen in the Devonian Chotecops, asteropygines Asteropyge, and Rhenops, and recently described in three-dimensional material from the Silurian Dalmanites. Once the trilobite was inverted, righting would not be a simple matter, especially if the dorsally directed spines had snagged in the sediment. An upended trilobite would probably be even more helpless than a beetle in this position and thus excluded from sexual competition.
It might also be dead!
Now the first thing that struck me when I saw this paper was the question that would have occurred to many of you: WHERE ARE THE BLOODY FEMALES?? One of the signs of male-male competition is that the structures used to compete are present in males but almost never in females, as they’re of no use in that sex—and detrimental to fitness if you don’t use them. Male deer have antlers, females do not. Body size, used for combat in elephant seals, is huge in the males, and much, much smaller in females. So if these trilobite horns really were tools used for the “combat” form of sexual selection (the other form, as pointed out by Darwin, is female preference), the females should be around but lack the ornaments. Where are they?
Gislick and Fortey suggest that the females were indeed around, but because they lack the tridents they have not been identified as females of Walliseropstrifurcata:
Since the diagnostic synapomorphy [JAC: shared derived trait] for Walliserops is the anterior trident, it would be likely that the female of the species has been classified in a different genus. That leaves two possibilities: either the females of the relevant species are at present unknown, or they are known but placed in another trilobite genus within Asteropyginae.
That mandates a search for trilobites that resemble the males but lack the horns. The authors raise another possibility: the females weren’t preserved or were offstage, living elsewhere, but this seems less likely:
If we extend the beetle analogy further, it is possible that the females are not preserved if some trilobites, like many dynastines, engaged in sex-specific aggregations; in this case, the females were not always present in the same locations as the males, although it is difficult to explain why the latter were selectively caught up in obrution events. [JAC: “Obrution” is rapid burial in the sediments, the way these creatures must have died and been preserved.]
I favor the “females not yet found” hypothesis. There’s one more hypothesis, which is mine: both males and females have tridents. I don’t know why this would be the case, although you could think that it’s used to take other individuals out of action in conspecific competition for food. But that makes little sense.
Finally, the authors found one example of W. trifurcatus with a deformed trident, having an extra spike (a “quadent”?). Here it is on the right. Note that the branching pattern can be asymmetrical in the normal three-pronged structure).
Because the individual on the right was an adult, Gishlick and Fortey suggest that the deformed structure did not prevent the bearer from growing up and thriving, and thus was unlikely to be used for some vital function like feeding. This adds a little more weight to the sexual-selection hypothesis.
The Upshot: The authors’ analyses and explanations seem plausible to me, though they’d be even stronger if they could find the females. That might be tough: in living species you could find them by looking at mating pairs or even seeing that the DNA was nearly identical, but this isn’t possible with fossilized trilobites, especially because in some living and sexually dimorphic species the females look very different from males. If the authors are right, and I think they are, then this quote from the paper is correct:
Walliserops provides the earliest example in the fossil record of combat behavior, very likely ritualized in competition for mates. Although fossil life habits are difficult to prove, the consilience of morphology, teratology, and biometric data all point to the same interpretation, making it one of the more robust examples of paleoecological speculation.
Today’s photos are a batch of microorganisms and small creatures sent in by reader Mary Rasmussen. Her captions and narrative are indented, and you can enlarge the photos by clicking on them.
If there’s water, there’s probably something living in it.
I collected a half gallon of water, muck, detritus, rocks, a tiny aquatic plant and 3 snails from some very shallow temporary pools along the Lake Michigan shore. Lake Michigan’s depth varies year-to-year. The pools sometimes last a few years and sometimes just a few weeks. This year the lake level was down and the pools dried up by the end of summer.
I put the water etc. in a 12 inch square glass aquarium with an L.E.D. light on top. These are the creatures living in the water that I was able to photograph.
The last 2 photos are Seed Shrimp that were living in 2 inches of water that had collected in a truck rut in a gravel road.
Aquatic Sowbugs (order: Isopoda) a freshwater crustacean, lived at the bottom of the tank, feeding on organic matter.
Two Hydra (phylum Cnidaria, class Hydrozoa, genus Hydra) After a month there were many of these predators in the tank. I could watch them for hours.
Hydra don’t show any signs of deteriorating with age, and there is speculation that they may be immortal. (I’m sorry but I can’t identify that creature on the left.)
Hydra with bud. The bud is a clone of the parent and will break free when mature.
A freshwater snail laid a trail of eggs on the aquarium wall. These are close to hatching.
Seed Shrimps (subphylum Crustacea, class Ostracoda) have a hard shell and use their antennae to move through the water. These were barely visible in the water of a truck rut.
I used a Nikon D500 camera with three off-camera flashes. For larger creatures (Sowbug, Hydra) I used a Nikkor 105mm macro lens with extension tubes. For smaller creatures (snail eggs, Cyclops, See Shrimp) I used a Laowa 25mm f/2.8 2.5-5X Ultra Macro lens with extension tubes.
Today’s batch of photos come from Costa Rica, and were taken by Fred Dyer. His notes and captions are indented, and you can enlarge the photos by clicking on them:
Some Photos from Costa Rica 10-20 July 2022
I recently traveled around Costa Rica with my family for about 10 days prior to a conference. Our itinerary included a day in the capital city of San Jose, a couple of days in the mountainous/volcanic region northwest of San Jose, and then several days along the central Pacific coast. Costa Rica is an amazing place, geologically, biologically, and culturally. Almost everything you see is beautiful. These photographs are a grab bag that don’t have much in common except that they were the ones that came out looking pretty good.
First, a few photos from near the town of La Fortuna and the Arenal volcano, including from a guided walk through a private rainforest reserve. On the walk we saw toucans, howler monkeys, army ants, leaf cutter ants and morpho butterflies, plus these (I welcome corrections on the species identifications):
Eyelash pit viper (Bothriechis schlegelii), which gets its common name from the hairlike scales protruding over each eye. It is a small snake, but one of the most dangerous in Costa Rica.
Stingless bees (Apidae : Apinae : Meloponini: Perhaps Tetragonisca sp?) guarding their nest entrance tube. There are something like 60 species of stingless bees in Costa Rica. These guard bees were 4-5 mm in length. The colony is enclosed in a cavity so its size is hard to know, but some species have several thousand workers in each colony.
View of the Arenal Volcano from the north. This volcano began erupting violently in 1968 and continued until 2010. Vapors still issue from the peak, although this picture shows only clouds:
From La Fortuna/Arenal we drove toward the Pacific coast, and stopped at a wildlife rescue center (Santuario Las Palmas) near the town of Cañas in Guanacaste province. The enclosures held rescued jaguars, pumas, ocelots, monkeys and several species of parrots. We also spotted some wildlife outside the enclosures:
Automeris metzlicaterpillar (larva of a Saturniid moth—in the same genus as the North American Io moth). This beauty was about 10 cm long
Same caterpillar after it moved onto a twig. The urticating spines supposedly produce a nasty venom. Here is what an adult Automeris metzli looks like. Whereas the larva relies upon aposematic signals and spines to deter potential predators from attacking, the adult is cryptic in the resting position, and exposes eyespots as a startle cue.
You can read more on Automerishere.
Black Ctenosaur (Ctenosaura similis), also known as the black spiny-tailed iguana, grazing at Las Palmas. These large lizards are extremely common along the Pacific slope:
In Manuel Antonio National Park, stingless bees (species unknown) on a Heliconia sp.:
Also in the park, Panamanian white-faced capuchins (Capuchin imitator) engaged in a groomfest, while baby looks on. These were part of a larger group of a dozen or so monkeys in a grove of trees about 3 meters above the ground:
Same monkeys, still grooming.
Back in town, a Groove-billed Ani (Crotophaga sulcirostris) with some insect yumminess for its nestling(s). These are large birds (a bit bigger than a grackle) in the cuckoo family. They often nest communally but this seemed to be a single mated pair. The nest was in a tree across the street from our rental house in Manuel Antonio. Pictures of the nestling(s) and the other parent didn’t come out so great.
Playa Hermosa, a black-sand beach about an hour north of Manuel Antonio. This is a destination for expert surfers, and the surf was really intense the day we were there.
American Crocodiles (Crocodylus acutus) basking next to the Tárcoles River below the “Crocodile Bridge.” This is a tourist attraction on the main coastal highway (Route 34). The travel guidebook said that there is a population of 2000 or more crocs in this river and the nearby Carara National Park. Crocodiles often rest with their mouths open to dissipate heat.
Today’s photos come from reader Mark Sturtevant, specialist in arthropod photography. His IDs and text are indented, and you can enlarge his photos by clicking on them.
Here are more pictures taken in 2020.
One day while hiking in the woods, a large flying beetle made a noisy passage across the trail. I managed to knock it down. This is Osmoderma scabra, and it’s only slightly smaller than a walnut.
After a few minutes it had enough, popped out its wings, and lumbered away through the air:
I recently showed a group of strange insects called bark lice. They’re in the same order as parasitic lice, but bark lice are more into feeding on lichens and algae. Some bark lice have wings; here is a handsome example of one. It is Cerastipsocus venosus.
Bark lice are pretty alert and fast. But evidently the one shown in the next picture was not quite fast enough. Based on some details like the relative length of the legs, my guess is that the spider is one of the running crab spiders (species unknown). It was quickly hauling its prey along the twig.
An extremely common visitor to our porch lights is this lovely little Geometrid moth known as the green pug, Pasiphila rectangulata. Cherry trees are one of their host plants, and we do have one, probably explaining why I see them so often.
Let’s stay with the Lepidoptera. Next is a lovely Virginia ctenucha moth (Ctenucha virginica), a species found along wood margins. They resemble the closely related yellow-collared scape moth that frequents fields, and together they are part of an extensive mimicry complex that includes several orders of insects. Some members of the complex are distasteful, or they sting, and others are imposters.
Next up is a caterpillar that was clearly preparing to form a chrysalis. Spiny caterpillars can be hard to identify, but I kept this one and it later emerged as a grey comma butterfly (Polygonia progne).
And next is that same butterfly with recently expanded wings after emerging from its chrysalis. The reason for its common name is because of the comma-shaped mark on the underside of the wings. The upper side of their wings are mostly orange, but they spend much time sitting with wings closed on the ground among the dead leaves. In this circumstance, they are nearly impossible to see!
Next up is a little planthopper called Acanalonia conica. These cute little insects are amusing to photograph, because when they realize they are being watched they deviously move to the back of the twig. The trick then is to extend a finger behind the twig, and that makes them sidle back out to sit in plain view.
The house centipede (Scutigera coleoptrata) is a fairly cosmopolitan species that favors living in houses. As a result, many people know what it’s like to live with house centipedes. Let’s see. . . they attain a size that makes them a bit unnerving, they move fast, and they do have a tendency to suddenly dart out across a wall while you’ve settled down for the evening. I think that about covers it. Folks who live with house centipedes always have strong opinions about them, although they really cause no problems.
Here are some photographs of one that are actually focus-stacked from dozens of pictures taken during a staged setting on the dining room table. Lights were kept off, save for a lamp, and that helped keep it calm. Even so, I am rather surprised this even worked. A few times it did zip away into the dark surroundings, and it was challenging to find again.
Today’s batch comes from regular Tony Eales from Queensland. His notes and IDs are indented, and you can click on the photos to enlarge them.
One of my favourite habitats is leaf litter, I think because it is often overlooked by the general public unless you’re a little kid. Something about lying down in the dirt, watching what is going on brings back my childhood wonder at the variety of life all around us.
So here’s a random selection of leaf litter denizens from around Brisbane Queensland.
First a common little jumping spider called Bianor maculatus. These spiders live in open grass and leaf litter. I was out one day hunting for Peacock Jumping Spiders (Maratus sp.) but all I found was dozens of these little guys.
What they lack in colour they make up for in their charming way of constantly being on the move and waving their forelegs around like antenna. To me this seems to be the first steps towards ant-mimicry, which is highly advanced in some tribes of jumping spider.
It did this individual no good however because shortly after I took this shot it was nabbed and consumed by a wolf spider.
This strange beast is a Short-tailed Whip Scorpion, which is a small order of arachnids called Schizomida. There are only fewer than 250 described species and externally they are all very similar. Generally, the largest are 5-6mm long and are found in humid tropical and subtropical leaflitter and soil in Africa, Australia, Asia and the Americas. The most common genus in Australia is Brignolizomus and that’s likely what this one is.
They have no eyes, but are active predators using their antenna-form forelimbs to find and investigate prey and their relatively large pedipalps to seize, subdue and grind up their victims.
Another strange beast that is common in the litter is millipedes in the Bristle Millipede order Polyxenida. Probably Polyxenus sp.
The leaf litter in Australia is the kingdom of ants. It’s nearly impossible to find anywhere without several species. This is a large Camponotus sp. that I’ve yet to identify.
This ant is perhaps my favourite but they are extremely difficult to photograph as they are always on the move. It is one of the so-called spider ants, Leptomyrmex rothneyi, found in subtropical rainforest leaf litter.
And another favourite is the Painted Strobe Ant, Opisthopsis pictus. These are less common in my area and tend to be in the drier open forests to the north and west. They have an odd stuttering gait that appears to be to confuse predators. It has been observed that they never walk with their strobe gait when inside their nests, only when out in the open.
The subtropical rainforest near where I live has plenty of species of snail but this one is the most spectacular. This is the Giant Panda Snail (Hedleyella falconeri). They are leaf litter specialists and are never found more than half a metre above the ground—unlike many of the other snails that regularly feed on the trunks and leaves of trees.
This is unsurprising given that an adult snail is the size of a tennis ball and a fall from any great height would be potentially fatal. They are under threat from collectors and the pet trade. They are almost impossible to keep in captivity as they require a high humidity and a thriving population of particular fungi on which to feed. Hence many are captured only to die in peoples’ vivariums.
Leaf litter in the open eucalyptus forest has many species of small orthoptera and this is one of my favourites. Macrotona mjobergithe Handsome Macrotona. Macrotona is a genus of spur-throated locusts mostly from Australia often associated with spinifex grasses.
Other common Hymenopterans in the leaf litter are various parasitoid wasps, the most common being velvet ants (Mutilidae), which is what I thought this was at first. However, as it turns out, this is Myrmecomimesis sp., a member of the cuckoo wasp family Chrysididae. Unlike many other cuckoo wasps (but like Mutilids), the females are wingless and spend their time hunting for Phasmid eggs in which to lay their eggs.
Phasmids in Australia produce seed-like eggs that are dropped into the leaf litter. Some have a part to the egg that is meant to be eaten by ants, who take the eggs into the nest where they develop in safety. These wasps run around manically tapping everything with their antenna looking for these eggs before the ants take them.
Another predator, this tiny Carabid beetle,Scopodes sp. hunting through for tiny prey, I’m guessing probably larvae.
One of those potential prey, defending itself with camouflage and silk with leaf-plate armour. One of the case moths in the family Psychidae. Maybe an early instar Lomera sp.
Send in your photos, please; the holidays will soon be on, and nobody will be reading or sending. Thanks!
Today’s photos, a great batch, come from regular Tony Eales from Queensland. His notes are indented, and you can enlarge his photos by clicking on them.
A grab bag of rainforest finds. I’ve been getting seriously addicted to doing night walks in the local rainforest. There’s a lot of different species out compared with the day, and different activities are going on.
Like cicadas emerging from their pupal shells, this one is a Green Grocer (Cyclochila australasiae). One of the favourite photos I’ve ever taken.
I encountered this mantidfly (Ditaxis biseriata) wandering about on a huge tree fallen limb. The ones I’ve found in the rainforest in the day have flown off quickly but this one seemed very interested in my lights.
A lot of sex seems to happen at night as well. Who would have thought that cockroach sex would be so weirdly beautiful? These are in the family Ectobiidae, but more than that I do not know.
There’s a few species I only ever see at night, like this huntsman (Heteropoda hillerae):
During the day these spiders (Genus Namandia in the family Desidae) stay deep in their messy cobweb retreats in the hollows and forks of trees. But at night they run out and grab anything walking around on the trunk of the trees. This hairy caterpillar’s spines were apparently no defence.
The lower trunks of the trees are full of these prehistoric looking pygmy grasshoppers (Tetrigidae). They are both armoured and camouflaged and difficult to photograph well, but worth the effort. This one is Vingselina crassa. [JAC: Look at those hoppers!]
Not just invertebrates come out at night but also vertebrates and normally shy frogs are rather easy to approach and photograph at night time. This one is the Dainty Tree Frog, Ranoidea gracilenta, a fairly common frog but one I never tire of photographing.
I have returned, and I hope that some of you have accumulated wildlife photos to send me for the cache. Now is the time!
Today’s contribution of spider photos is from Tony Eales of Queensland. His notes and IDs are indented, and you can enlarge the photos by clicking on them.
Spider guru Dr Robert Raven, Head of Terrestrial Biodiversity & Senior Curator of Chelicerata at the Queensland Museum, has been telling me for some time now that the way to survey for spiders is to leave your diesel engine running for a while, and the spiders will come crawling out of the surroundings like hypnotised zombies. I had tried this a few times with little success, but recently I tried it on some sandy loam in coastal heath near Bundaberg, Queensland, and it worked beyond my wildest expectations.
Big spiders, little spiders, huntsmans and jumpers and especially ground spiders all came out toward the car. As did a lot of native cockroaches. And at one site the engine vibrations seemed to induce a bunch of spiders to compulsively climb a small tree near the car. I can’t wait to try it again.
Here’s a small sample of some of the things that came running to the siren call of the diesel engine.
One of the larger spiders to come out (around 20mm) and an unusual one. Asadipus sp. There are only seven observations of this genus on iNaturalist. It comes from an Australasian family Lamponidae which has the undeserved reputation of giving necrotic bites, though there is no solid evidence for this idea.
This little guy is probably Epicharitus sp or something related. This genus of striking black and white spiders belongs to the family Gnaphosidae. This is a varied cosmopolitan family known rather unhelpfully as Ground Spiders. [JAC: Wikipedia notes that “Epicharitus is a monotypic genus of Australian ground spiders containing the single species, Epicharitus leucosemus.”, so that may be the species.]
This one isMituliodon tarantulinus, also knowns as the Little Tarantula even though it’s not remotely related to tarantulas. It’s in the family Miturgidae with the ominous common name of Prowling Spiders.
This is a juvenile wolf spider (Lycosidae). As it’s so young, it’s hard to guess at the ID. Quite pretty, though.
By far the most common family attracted to the car were members of the family Zodaridae AKA Ant Spiders. This one isHabronestes hunti and the next two are ones I have yet to get an ID for.
And lastly a couple of the spiders that climbed the small tree in response to the engine vibrations. Hamataliwa sp from the Lynx Spider family Oxyopidae.