Readers’ wildlife photos

December 6, 2022 • 8:15 am

Keep those photos coming in, and thanks to the people who answered my call for pictures.

One of them was reader Mary Rasmussen, who sent some lovely insect photos. Her captions and IDs are indented, and click on the photos to enlarge them.

I noticed butterflies, bees and flies covering the wild native Boneset plants flowering along the northern Lake Michigan shore, but wind made it hard to photograph them. Wind is a problem for photographing insects, so I tried planting 3 Boneset seedlings in a 16″ pot. They are easy to grow, bloom for weeks in August or early September and always attract a crowd. I drag the pot to a sheltered spot to photograph on windy days. The plants are perennial and overwinter well in my unheated (Zone 5b) garage. They last for years if I remember to water them once during warm winters. In a cold winter they need no care at all.

Every summer is different. This year the Boneset plant was covered in different types of flies, wasps and bees. They pushed out the occasional butterfly that tried to land. They were so focused on getting nectar that they mostly tolerated my camera getting close.

3 Boneset plants in 16” pot:

Common Eastern Bumble Bee (Bombus impatiens) with pollen basket on hind leg:

Orange-belted Bumble Bee (Bombus ternarius):

Golden Northern Bumble Bee (Bombus fervidus):

Cluster Fly (Pollenia rudis):

Clockwise from top: Cluster Fly, Friendly Fly (Sarcophaga aldrichi) and unknown orange fly:

Common Green Bottle Fly (Lucilia sericata):

Flower Fly mimicking a bee (Helophilus species):

Wasp-mimic Fly mimicking a wasp (possibly ):

Another type of Flower Fly also mimicking a bee (Toxomerus geminatus):

Northern Paper Wasp (Polistes fuscatus):

A larger wasp tussling with a smaller wasp. The wasps often took ownership of the flowers and aggressively pushed away any intruders:

The larger wasp is triumphant after vanquishing its smaller rival. Actually, I see this leg-raise behavior in wasps and bees often. They seem to use it as a warning signal. Bumble Bees seem to use it as more of a request. They will raise a leg when my lens gets too close and as I move back they will lower their leg. Their communication to me is pretty clear. They have never tried to sting me. I don’t push my luck with the wasps.

Every now and then a butterfly will land and have a few seconds to sip nectar. This Red Admiral butterfly (Vanessa atalanta) is feeding and showing its beautiful underwings.

I use a Nikon D500 camera with Nikon VR 105mm f/2.8G macro lens. For smaller subjects I add a Raynox DCR-150 snap-on macro lens. I’m currently using a folding diffuser from AK Diffuser:

Recommended book: Insects of the North Woods by Jeffrey Hahn.

Readers’ wildlife photos

December 3, 2022 • 8:15 am

It’s been a while since we’ve had an illustrated biological tale from Athayde Tonhasca Júnior, but we get one today—on the work of one Ch. Darwin on orchis. Athayde’s prose is indented, and you can click on the photos to enlarge them.

Evolutionary dead ends and sticky contrivances: Darwin the botanist

Athayde Tonhasca Júnior

In 1842, the Darwin family – Charles, his wife Emma, and their two children William and Anne – moved to Down House in the village of Downe, England. The Darwin patriarch, who had travelled the world aboard H.M.S. Beagle (1831–1836), would spend the remaining 40 years of his life in quiet isolation at home because of ill-health. Darwin’s condition (whose origin still puzzles scholars) did not slow him down; he embarked on several projects such as monographs on coral reefs and barnacles, and of course overseeing the publication of On the Origin of Species. But Darwin spent most of his time working with plants, which are convenient study subjects for someone with a sedentary lifestyle. Assisted by gardeners and occasionally his children, Darwin observed and experimented with cabbage, foxglove, hibiscus, orchids, peas, tobacco, violets and many other species in his garden and glasshouse.

The Old Study at Down House, where Darwin completed On the Origin of Species by Means of Natural Selection. Evolutionists are encouraged to go on pilgrimage to Down House provided they are physically and financially capable.  [JAC: it’s not expensive and is close to London. Anybody interested in Darwin and evolution MUST go! And the town has two lovely pubs.]

Darwin’s glasshouse at Down House, where he conducted many experiments © Tony Corsini, Wikimedia Commons.

Among various major contributions to botany (detailed by Barrett, 2010), Darwin documented the importance of cross-fertilisation (i.e., the transfer of pollen between different plants) for producing healthy offspring. Ever meticulous about supporting his theories with data, Darwin amassed eleven years of continuous observations to highlight the superiority of cross-fertilisation over self-fertilisation, i.e., the transfer of pollen within the same flower or between different flowers on the same plant.

Indeed, the great majority of flowering plants predominantly or exclusively outcross – that is, they mate with other individuals – even though they could easily self-fertilise because they are hermaphroditic (their flowers contain both male and female sexual organs). In fact, numerous flowers have mechanisms to avoid self-fertilisation. At best, many self-pollinating species (or ‘selfers’) exhibit mixed mating systems.

The bee orchid (Ophrys apifera). Despite its name, this orchid is mostly a selfer in northern Europe. In the Mediterranean, where this orchid is more abundant, its flowers are pollinated by bees © Bernard Dupont, Wikimedia Commons. [JAC: note that some petals have evolved to resemble a female bee. When a male sees the flower, he tries to mate with it, and the pollen sacs above his head stick to the body.  Frustrated, he flies away with the pollen, forgets about being duped, and tries to mate with yet another flower, whereby cross-fertilization is effected. This is a great example of a plant mimicking an insect. See more below.]

Self-pollination has some advantages: it helps to preserve desirable parental characteristics when a plant is well adapted to its environment. Because selfers do not depend on pollen carriers, they can colonise new habitats with a handful of individuals. Selfers do not have to spend energy on nectar, scents, or substantial quantities of pollen. Self-pollination is useful to farmers, as the genetic identity of a variety or cultivar is easily maintained, without requiring repeated selection of desirable features.

Self-pollination sounds like a convenient and rational lifestyle, but there are catches, and they are considerable. Selfers’ limited genetic variability makes them vulnerable to environmental changes; a hitherto well-adapted population can be driven to extinction if no individuals are adapted to novel conditions – and changes are inevitable, given enough time. Selfers are also particularly susceptible to inbreeding depression:  if the population is homogeneous, genetic defects cannot be weeded out by genetic recombination.

Taking into consideration the long-term hazards of selfing, it seems paradoxical that 10 to 15% of all flowering plants from many taxonomic groups made the transition from outcrossing to full self-fertilisation. Darwin proposed an explanation for this puzzle: cross-pollinated species would turn to self-fertilisation when pollinators or potential mates become scarce. In other words, self-fertilisation assures survival when outcrossing becomes inviable. Darwin’s hypothesis, currently known as the ‘reproductive assurance hypothesis’, continues to be the most accepted explanation for the evolution of self-fertilisation.

Remarkably, researchers were able to quickly induce the transition from cross-pollination to self-pollination in the common large monkeyflower (Erythranthe guttata, previously known as Mimulus guttatus) by preventing plants’ contact with pollinators (e.g., Busch et al., 2022). Monkeyflowers kept in a glasshouse with no pollinators for five generations increased the production of selfing seeds and showed a reduction in the stigma to anther distance – this feature, known as herkogamy, is one of the indicators of ‘selfing syndrome’: the greater the distance between stigma and anther, the greater the likelihood of the stigma receiving external pollen, thus the lower the chance of self-pollination. After nine generations, plants experienced a significant reduction of genetic variability. Monkeyflowers kept in another glasshouse with free access to the common eastern bumble bee (Bombus impatiens), one of the plant’s main pollinators, underwent none of these effects.

L: The common large monkeyflower, a native to western North America. Its wide corolla and landing platform are convenient for its main pollinators, bumble bees © Rosser 1954, Wikimedia Commons. R: Diagram of a large monkey flower with the upper corolla removed to show the reproductive structures © Bodbyl-Roels & Kelly, 2011.

A common eastern bumble bee; its absence induces selfing in large monkey flowers © U.S. Geological Survey Bee Inventory and Monitoring Lab.

What do these observations about the monkey flower tell us? For one thing, they are cautionary tales about the risk of losing pollinators. A variety of human disturbances such as agriculture intensification, loss of habitats, and diseases have caused a decline of some insect populations, including pollinators. A scarcity of flower visitors may threaten pollination services directly, or induce some plants to adapt quickly and become self-pollinated. Adaptation sounds good, but selfers’ lower genetic diversity and reduced capacity to adjust to environmental vicissitudes make them vulnerable to extinction.

The renowned botanist and geneticist G. Ledyard Stebbins (1906-2000) suggested that selfing is an evolutionary dead end: it is advantageous in the short term but harmful in the long run. And because the transition from outcrossing to selfing is irreversible, according to Dollo’s Law (structures that are lost are unlikely to be regained in the same form in which they existed in their ancestors), self-fertilization ends up in irretrievable tears. And the monkeyflower has shown that it all may happen before we notice it.

While Darwin worked in his garden, somewhere in the British countryside a four-spotted moth (Tyta luctuosa) landed on a pyramidal orchid (Anacamptis pyramidalis), intending to sip some nectar. The moth certainly didn’t expect to end up with its proboscis – the elongated mouthparts used for sucking by butterflies and moths – covered with blobs of pollen. But that was the least of the moth’s problems, as disaster loomed: the hapless wanderer was captured by an unknown collector and became a model for George B. Sowerby (1812-1884), the illustrator of Charles Darwin’s masterpiece about orchid fertilisation – On the Various Contrivances by Which British and Foreign Orchids Are Fertilised by Insects, and On the Good Effects of Intercrossing.

An illustration from Charles Darwin’s book on fertilisation of orchids depicting the head of a four-spotted moth with its proboscis laden with several pairs of pollinia from pyramidal orchids. Names of the species involved have changed since then.

Those globules of pollen attached to the moth’s proboscis are known as pollinia (sing. pollinium). Each unit contains from five thousand to four million pollen grains, depending on the species. The grains are stuck together with pollenkitt, an adhesive material found in almost all angiosperms pollinated by animals. A stalk-like structure connects the pollinia to a gluey pad known as viscidium, and the whole assemblage is often referred to as a pollinarium.

A pollinarium: the pollinia on the toothpick are held in place by the sticky viscidium © Frederick Depuydt, Wikimedia Commons.

Pollen grains lumped together in a sticky package are not easily carried away by water or wind. As Darwin learned from his observations and experiments, this is done by animal vectors, mostly wasps and bees (although moths, beetles, flies and birds do the job for a reasonable number of orchid species). Having pollen grains in a single unit reduces wastage during dispersal, but it’s a risky strategy: a lost pollinium means no pollination at all. So orchid flowers have undergone dramatic morphological transformations to assure that pollinia are picked up by the right pollinator:

‘If the Orchideæ had elaborated as much pollen as is produced by other plants, relatively to the number of seeds which they yield, they would have had to produce a most extravagant amount, and this would have caused exhaustion. Such exhaustion is avoided by pollen not being produced in any great superfluity owing to the many special contrivances for its safe transportal from plant to plant, and for placing it securely on the stigma. Thus we can understand why the Orchideæ are more highly endowed in their mechanism for cross-fertilisation, than are most other plants.’ (Darwin, 1862, Fertilisation of Orchids).

What are some of these contrivances mentioned by Darwin? Orchids’ stamens (comprising anthers and filaments, the male reproductive parts) are fused with the pistil (which are the female reproductive parts: stigma, style and ovary) to form a structure known as a column. The anther (the pollen-producing organ) is located at the distal – away from the centre – end of the column, and the stigma (the pollen-receiving organ) lies close by. Directly below the column there’s an enlarged petal named labellum or lip, which often is noticeably different from other flower parts in its colour, markings, or shape. For nectar-producing species, nectaries are located at the base of the labellum.

Parts of an orchid flower © Thomas Cizauskas, CC BY-NC-ND 2.0:

So the stage has been meticulously set. The distinct labellum is a perfect landing strip for an insect attracted by the orchid’s rewards, be they real (nectar) or not (when physical or chemical decoys are deployed). The pollinator lands on the labellum, touches the tip of the column, and goes away with pollinia securely adhered to its body by the viscidium, which works better on smooth surfaces such as the eyes and mouthparts of insects and beaks of birds. When the pollinator visits another flower, the pollinia are likely to be transferred to the stigma. Sticky pollinia and viscidium ensure secure removal of pollen, minimal losses during transit, and a high probability of deposition on a receptive stigma.

An orchid bee (Euglossa sp.) with pollinia attached to it © Eframgoldberg, Wikimedia Commons:

These morphological features have evolved independently in two plant groups: orchids (family Orchidaceae) and milkweeds (subfamily Asclepiadaceae of the family Apocynaceae). But pollinia are relatively more important for orchids; with more than 26,000 described species, they make up about 8% of all vascular plants and span a range of habitats in all continents except Antarctica; there are more orchid species in the world than mammals, birds and reptiles combined.

Orchids’ highly specialized ‘lock and key’ pollination system reduces the chances of pollen being picked up by the wrong flower visitor or being transferred to the wrong plant species; the selective adaptations towards the right flower-pollinator association must have contributed to orchids’ enormous richness and diversity of forms. It’s amazing what a dab of glue here and there can do.

A figure from the 1877 edition of Fertilisation of Orchids. A pencil inserted into the flower of an early-purple orchid (Orchis mascula) comes out with an adhered pollinium. Within 30 seconds, loss of moisture bends the stalk forward. If the pollinium was attached to a bee, it would be perfectly positioned to touch a receptive stigma.

Readers’ wildlife photos

November 26, 2022 • 8:15 am

Today we have photos from several readers. Their captions and IDs are indented; click to enlarge the photos.

First a few photos from reader Ken Phelps:

Attached photos of a fungus growing on a dead Arbutus tree, and backlit bark peeling from a live Arbutus. I believe the fungus is Laetiporus gilbertsonii, although I would take that with a grain of salt – literally, perhaps, as L. gilbertsonii is edible.

And from last year, a Roswell pear. As Ken says, “We are not eating alone!”:

Foggy morning dog walk in the yard:

From Rachel Sperling:

I was saving this photo for when I had more to share, but I saw your request this morning. I’m pretty sure this is a dark fishing spider (Dolomedes tenebrosus). I encountered it on the New York section of the Appalachian Trail earlier this month. In addition to insects (not sure what type of beetle this one has caught) larger ones are able to catch fish. According to Wikipedia, their bodies are covered with hydrophobic hairs that allow them to run on water (suck it, Jesus). When they submerge, the air trapped in these hairs becomes a thin film, allowing them to breathe underwater. The air makes them quite buoyant, so they have to hold onto a twig or a rock in order to stay submerged. I think they’re really cool.

Also sharing a photo I took last night [June 23, 2022] of the ALMOST full strawberry moon. This is from a park in Meriden, Connecticut, which has a lovely ridge that offers views to the east and west. This was taken around 8:30.

Two photos from Divy:

Ivan and I love to relax in our backyard each evening with a cold beer, and just watch the birds and the insects frolic in our garden.

I think this is a Red-tailed Hawk [Buteo jamaicensis].

A Red-bellied woodpecker [Melanerpes carolinus]:

A male Northern Cardinal and two females [Cardinalis cardinalis]:


Readers’ wildlife photos

November 25, 2022 • 8:15 am

We resume our readers’ photos after the Thanksgiving hiatus. Today’s contributor is Rik Gern, who sends photos from Texas and Wisconsin. Rik’s notes are indented, and you can enlarge the photos by clicking on them.

I hope there is something in this collection of pictures that you can use for your readers’ wildlife pictures feature. This is a random collection of photos united by the theme “saved by photoshop”. Each one was an initial frustration because it bore no resemblance whatsoever to the image I had in my mind’s eye, but with the help of heavy editing I hope I was able to turn a bunch of sows’ ears into, if not silk purses, at least serviceable satchels.

The first half come from my neighborhood in south Austin, TX and most of the others are from St. Germain, Wisconsin.

It’s fairly rare that I see a Globular Drop Snail (Helicina orbiculata), but their shells are quite common. The sight of these two shells nestled together put my mind into anthropomorphic overdrive as I imagined the big one protecting and sheltering the smaller one, although both were in fact abandoned shelters.

The Spineless Prickly Pear Cactus (Opuntia ellisiana) in the front yard is in a constant state of growth and decay. This one had a dry rot spreading through one of the pads. The glochids look like little puffs of cotton, but don’t be fooled; they harbor spines that are just as painful as the ones on the healthy part of the plant!

Pink Woodsorrel (Oxalis debilis) is a lovely little wildflower that pops up every spring and summer. They always catch my attention and look like they’d be photogenic from any angle, but they don’t always stand out to the camera, so I tried playing with extremes of light and dark to make these “pop”.

Every now and then you see a blossoming Century Plant (Agave americana) in Austin. I’m glad I got a picture of this one, because the next time I came by not only was the blossom gone, but the leaves were hacked into short stumps that made the entire plant fit in the grassy area between the sidewalk and curb.

Traveling north to Wisconsin, the pictures of the pine trees were taken on a foggy morning. The scene was beautiful to the naked eye, but the pictures just looked overexposed, so I had to play with photoshop’s “water color” filter, among others, to try to do justice to the look of the morning fog. (I believe the first photo is red pine [Pinus resinosa] and the second is balsam fir [Abies balsamea].)

You’d think it would be easy to get a good picture of a Marginal Wood Fern (Dryopteris marginalis), but none of the ones I took really stood out, so I just went to town with one of them and “electrified” it!

Back to Texas for this one. I can’t remember where it was taken but it was somewhere in central Texas in the springtime. I believe it is a Star of Bethlehem flower (Orthinogalum umbellatum), but I’m not sure. The little flowers are pretty, but I had to really exaggerate the sharp and soft focus in the foreground and background to make this one show up. I got a little obsessed with it and three or four days and two versions of photoshop later it morphed into something that looks like Georgia O’Keefe meets the Day of the Dead!!! (last photo):

Readers’ wildlife photos

November 22, 2022 • 8:15 am

We’re running low on photos, folks, so if you have some good ones, you know what to do. .

Today’s batch comes from Brian Cox, an instructor at Assinboine Community College in Manitoba (see his earlier photos here). Brian’s notes and IDs are indented, and you can enlarge the photos by clicking on them.

A crayfish claw jammed between dock boards in Kenora, Ontario, Canada. I don’t know the species of crayfish, but here are some possibilities.

Stilt sandpiper (Calidris himantopus) in my hometown of Brandon, Manitoba.

A neighbour threw his Christmas tree on a bonfire. I was able to capture the vibrant colours, but I can only guess at the tree species. Is it a white or black spruce? Perhaps a jack pine?

Capturing a red-tailed hawk (Buteo jamaicensis) in flight with a manual-focus zoom lens can sometimes come down to luck. My city is surrounded by farmer’s fields, prime hunting grounds from these hawks.

This red-tailed hawk was happily stripping pieces off a Northern pocket gopher (Thomomys talpoides) until I got too close. The image is a little out of focus…

And this gopher completely objects to the hawk’s lunch preferences.

I startled this North American porcupine (Erethizon dorsatum), but waited for it to find the right safety-tree to climb up. I think it gave me a little smile.

Riding Mountain National Park is a one-hour drive from my home. There are approximately 1000 American black bears (Ursus americanus) in a 2,969 km2 (1,146 sq mi) area. This one was enjoying fresh dandelions (Taraxacum officinale).

Readers’ wildlife photos

November 21, 2022 • 8:00 am

Today we have the second batch of Arizona plant photos and landscapes sent by reader Bruce Cochrane (the first batch is here). His captions and IDs are indented, and click on the photos to enlarge them.

As promised, here are some photos of plants and their flowers (and some landmarks) taken over the years in the vicinity of Tucson, more specifically from Ironwood Forest National Monument to the north, Buenos Aires National Wildlife Refuge to the south, and Organ Pipe National Park to the west.

Texas Prickly Pear (Opuntia lindheimeri) The taxonomy of this genus is a mess, with suggestions of their being multiple evolutionary origins of species (polyphyly) as well as extensive interspecific hybridization:

Prickly Poppy (Argemone pleiacantha):

And of course the Saguaro cactus (Carnegiea gigantea), here in bloom:

Two of our favorite landmarks.

 Baboquivar Peak, which overlooks Buenos Aires and the only site for technical rock climbing in Arizona.

Ragged Top, at the heart of Ironwood Forest National Monument.

And finally, two human impacts, one historic and an unfortunate contemporary one. . . 

Petroglyph in Saguaro National Park West.

The Mexican Border:

Readers’ wildlife photos

November 12, 2022 • 8:30 am

Today’s photos come from reader Susan Harrison, an ecologist at UC Davis. Susan’s narrative and IDs are indented, and you can enlarge the photos by clicking on them.

Piute Pass in the high Sierra Nevada

These photos are a companion piece to my pictures of the arid White Mountains and their ancient bristlecone pines. In August 2022, just after visiting the White Mts, I crossed Owens Valley and hiked up Piute Pass Trail — one of the shortest ways into the lush meadows and glaciated granite of the high Sierra Nevada. The trail starts at North Lake (9,276’), soon enters the John Muir Wilderness, and ascends to Piute Pass (11,423’) in four steep miles.  From there, the trail traverses Humphreys Basin and reaches  the splendid section of the Pacific Crest Trail known as Evolution Valley.

Historical side note:  Evolution Valley was named by Theodore Solomons, who explored and mapped the Sierra Nevada, and who named some of its tallest peaks for Darwin, Wallace, Haeckel, Huxley, and Spencer because these evolutionary pioneers were “at one in their devotion to the sublime in Nature.”

Even in the late summer of a drought year, the Piute Pass area abounded in water, wildflowers, and animal activity, a far cry from the austerity of the nearby White Mts.

Humphreys Basin from Piute Pass:

Sierra Gentians (Gentianopsis holopetala) and Lemmon’s Indian Paintbrush (Castilleja lemmoni):

Monkeyflower (Mimulus guttatus/Erythranthe guttata) – this widespread wildflower and its many close relatives are a “model system” for eco-evolutionary research:

Baby Elephant’s Head (Pedicularis attollens), an alpine specialist plant:

American Pika (Ochotona princeps), an alpine specialist animal:

Yellow-bellied Marmots (Marmota flaviventris):

Golden-mantled Ground Squirrel (Callospermophilus lateralis):

Dark-eyed Junco (Junco hyemalis), which were abundant on and around the Limber Pines (Pinus flexilis):

Williamson’s Sapsucker (Sphyrapicus thyroideus), a subalpine forest bird that was a “life-lister” for me:

Yellow-rumped Warbler (Setophaga coronata):

Rufous Hummingbird (Selasphorus rufus) on a streamside Tower Larkspur (Delphinium glaucum):

A Sierra Lily (Lilium kelleyanum) overhanging a stream:

Readers’ wildlife photos

November 8, 2022 • 8:00 am

We’re back with a selection of photos from Tony Eales from Queeensland. Tony’s notes are indented and you can (and should) enlarge his photos by clicking on them.

I had to go to the Burnett River region for work and spent the nights investigating the habitat known, rather oxymoronically, as ‘dry rainforest‘. It’s a highly diverse forest type that once covered a lot of coastal and subcoastal subtropical Queensland. These days, apart from creek lines and rocky hills and gorges, most has been cleared and fragmented for livestock and agriculture, particularly on the rich red basaltic soils of the South Burnett.

One conservation park I visited was no more than 400m by 200m, but represented probably the only remnant patch on flat red soil in the region. Despite this the diversity was pleasing.

The best find was a newly emerged pie-dish darkling beetle Cillibus ovalis.

 I went through the records on Atlas of Living Australia and the last recorded sighting of this beetle was 1953 and before that 1870. I suspect it is adapted to the particular soil and habitat that has mostly been lost through agriculture.

It was here that I also found my first Four-barred Swordtail butterfly, (Protographium leosthenes ssp. leosthenes). With my camera setup I can photograph butterflies only when they’re asleep. They’re too fast and nervous in the day.

I also went to the nearby Boat Mountain Conservation Park. This is a larger reserve with more habitat types, but is a rocky hill with none of the rich red soil habitat. The dry rainforest here is dominated by the prickly Capparis sarmentosa known as Scrambling Caper. It was the perfect time of year for flowers.

And many branches contained numbers of sleeping Caper White butterflies (Belenois java) and I found their eggs on one spent flower bract.

I also photographed my first native passion flower (Passiflora aurantia ssp. aurantia). I find many introduced species so this one was pleasing to see. Its leaves also held the eggs of the Glasswing butterfly Acraea andromacha.

Newly moulted adult beetles were emerging here too—like this large wattle-boring longicorn Xystrocera virescens.

And I found a species I’d been wanting to photograph for a long time: the green-bellied huntsman, Typostola barbata.

Readers’ wildlife photos

November 7, 2022 • 8:15 am

We’re back to wildlife photos, and today’s batch comes from Brian Cox, an instructor at Assinboine Community College in Manitoba. His notes and IDs are indented, and you can enlarge the photos by clicking on them.

You don’t have to trek into the vast wilds to find beautiful creatures. All of these images were taken in my yard or city I live in: Brandon, Manitoba, Canada.

Common black ants (Lasius niger) on a willow branch work with a cluster of aphids (Aphidoidea) and eggs.

A garden spider (Araneus diadematus) waiting for a catch.

A daisy (Leucanthemum vulgare) seen through a raindrop balanced on a daylily leaf (Hemerocallis fulva):

A lance-tipped darner dragonfly (Aeshna constricta) clinging to a Virginia creeper (Parthenocissus quinquefolia) stem:

A sawyer beetle (Monochamus scutellatus) is about to make a move.

This little house sparrow (Passer domesticus) was sitting right outside my kitchen window, puffed up against the cold.

I took one step too close for this pair of Canada geese (Branta canadensis).

This common raven (Corvus corax) has scored some fresh northern pocket gopher (Thomomys talpoides).

A hike in the Sierra foothills

October 31, 2022 • 12:30 pm

Yesterday my friend Phil and I took a long hike (though it was only 3.4 miles long, it was a tortuous path with ups and downs) in the Sierra Nevada foothills: we took the Western States Trail near Auburn, which connects with other trails going all the way east to Lake Tahoe.

There are several viewpoints looking down to the North Fork of the American River, below. About fifty years ago they proposed to build the Auburn Dam here, which would have filled this beautiful valley with water. But the project ran out of money, and work on the dam was suspended.  I am glad. Think of all the animals and plants that would be killed by this flooding! But some day they may finish the dam.

We found a vine of wild grapes (Vitis vinifera, the ancestor of Concord grapes) and decided to mash them up to see if black flies (D. persimilis or D. pseudoobscura, species I worked on) could be caught. Their ecology, including what adults and larvae feed on, is virtually unknown, and I spent a long time during my postdoc trying to find out, No success. Here we have a native, wild-grown berry that might attract flies, so we put a grape moosh in a vial and left it during our hike.

Phil placing the grape mash in a cool area at the base of a tree. Sadly, when we returned there were no flies, or other insects, on the mash. It’s curious that two of the most genetically well-studied species of Drosophila (by Dobzhansky, my academic grandfather) have an ecology that’s a mystery. This is also true of D. melanogaster, the genetically best-studied species of fruit fly, but where it lives in Africa—if it’s still extant in the wild—is unknown.

A humongous cone of gray pine (Pinus sabiniana), a California endemic. Each bract hides a tasty seed (“pine nuts”), which the squirrels work hard to obtain:

An extracted pine nut, itself covered with a hard shell.

Christmas berry or toyon (Heteromeles arbutifolia), a perennial shrub native to the west coast of North America.

Below is one of the two great finds we made on our hike, though it’s not rare: it’s a cynipid wasp gall on the stem of an interior live oak (Quercus wislizenii). Galls are structures that are “made” by larval insects whose mothers laid eggs on either stems or leaves of plants.

In this case the mother was the live oak apple gall wasp (Callirhytis quercuspomiformis). This species of tree, like others, can be parasitized in this way by several species of wasps, but each species makes only one type of gall. In this case a yellow, golf-ball-sized gall also has prickles to protect it against predators.

Below: clearly, two wasp eggs were laid, and the larvae somehow form this gall (as all galls are formed) by hijacking the plant’s developmental system to form a large, hard tumor that protects the larvae until they pupate and hatch. The adults then chew themselves out of the gall.

This is an amazing evolutionary phenomenon, for a gall can be regarded as an “extended phenotype” of the wasp (or whatever insect makes it), which has evolved to make the plant build a house for the larvae. Even the spines on the gall, which protect it against predators, are somehow coded in the wasp’s DNA: wasp genes that somehow make the plant’s own genes produce spikes. I’m not an expert on galls, but I think we have no idea how the insect manipulates the genome of the plant to make such a structure.

Galls are one of the marvels of natural selection, and something that Phil and I discussed in detail on our hike. It’s a great mystery, too, and would be a fascinating–though formidable–problem for scientists and Ph.D. students to work on. How do the parasite’s genes hijack the plant’s genes to mold such amazing structures?

Here is a different gall (the thickened part of the stem) made by a different wasp, but on the same species of oak–the interior live oak. The shape of the gall is diagnostic of the insect species that produced it. Galls can appear on both stems and on leaves.

This was our second great find. I saw a woodpecker flying by, and it settled in a nearby tree. It turned out that this was an acorn woodpecker (Melanerpes formicivorus), and it had several mates on a dead oak branch. You may know of this woodpecker, as it’s famous for its “granaries”: trees or branches in which it drills holes to store acorns over the winter.  They are also cooperative breeders. Here are three on a dead oak branch; you can see the holes for storing acorns:

Wikipedia‘s description of this storage system:

Acorns are stored in small holes drilled especially for this purpose in “granaries” or “storage trees”–usually snags, dead branches, utility poles, or wooden buildings. Storage holes–always in dead tissue such as bark or dead limbs–are used year after year, and granaries can consist of thousands of holes, each of which may be filled by an acorn in the autumn. Access to acorn crops influences the composition of acorn woodpecker communities. In one study in New Mexico, there were about 90% of non-breeding adults per social unit in 1976, a year of a poor acorn crop. The following year, 1977, there was a significant increase in acorn production and a correlating decrease in non-breeding adults per unit.

Although acorns are an important back-up food resource, acorn woodpeckers primarily feed on insects, sap, and fruit. They can be seen sallying from tree limbs to catch insects, eating fruit and seeds, and drilling holes to drink sap.

The woodpeckers then collect acorns and find a hole that is just the right size for the acorn. As acorns dry out, they are moved to smaller holes and granary maintenance requires a significant amount of the bird’s time. The acorns are visible, and a group defends its granary against potential cache robbers like Steller’s jays and western scrub-jays.

It’s interesting that they find acorns to fit the holes, and move the acorns as they shrink.  Look at all the holes in this tree!

Here you see some of the holes filled with acorns:

After the hike, when it had become hot, there was nothing else to do but find a brewski in the lovely small town of Auburn. I didn’t want an overhopped IPA at the local brewpub, but went for a refreshing cherry-flavored gose beer, a variant of Belgian fruit beers.

A fitting end to our hike: