Category: plants

Readers’ wildlife photos

December 3, 2023 • 8:30 am

I found a wildlife contribution that I had overlooked; it’s from Athayde Tonhasca Júnior, and is especially appropriate for these cold winter months. Click on the photos to enlarge them.

Come in, she said, I’ll give ya shelter from the storm

Life in the mountains can be harsh, even for species adapted to cold temperatures and scarce resources. In these habitats, a mountain avens flower (Dryas octopetala) can be a safe harbour for a fly or the occasional bee. There insects get more than pollen and nectar from the flowers; they also get warmth. The temperature on a mountain avens flower can be up to 30 C higher than the surrounding air.

Warm and cosy mountain avens flowers © SiberianJay, Wikimedia Commons:

Mountain avens flowers are warm because they follow the sun throughout the day, a phenomenon known as heliotropism or solar tracking. Moreover, these flowers are usually bowl-shaped, so sunlight is reflected towards their centre. Heliotropism and flower structure allow the plant to function like a satellite-tracking antenna, maximizing light interception.

A mountain avens flower © Robert Flogaus-Faust, Wikimedia Commons:

A tracking radar © Daderot, Wikimedia Commons:

We don’t know for sure how these flowers rotate to keep up with the sun’s position, but we can assume auxins are behind it. This group of hormones are involved in just about every aspect of plant growth and development, including phototropism (growing towards light).

Left: auxins (pink dots) are evenly distributed in the plant’s tip. Centre: the repositioning of the sun causes auxins to migrate to the shaded side. Right: the concentration of auxin stimulates cells to grow or elongate © MacKhayman, Wikimedia Commons:

Mountain avens’ heliotropism may be similar to what happens with a sunflower (Helianthus annuus) seedling. In the morning, the plant’s stem and upper leaves face east. As the day progresses, auxins move from the western to the eastern side of the plant. Auxins promote water absorption and tissue elongation, so the plant slowly bends westwards. The auxin gradient is reversed at night, and the plant is reoriented eastward. However, this cyclical movement stops when the flower matures. So, contrary to what some people think, fully-formed sunflower blooms do not follow the sun; they are always facing east (although wind or rain can change their position).

Solar tracking of a sunflower plant © Kutschera & Briggs, 2015:

Heliotropism is not the only way for a plant to warm up: fermentation also does the trick.

The stinking hellebore (Helleborus foetidus) is a favourite of many gardeners in Europe and America for its evergreen foliage and the abundance of bell-shaped flowers produced in late winter. The adjective ‘stinking’ is a bit libelous, and so is the plant’s alternative name, dungwort. Although not fragrant, the stinking hellebore produces a strong odour – often described as ‘meaty’ – only when its leaves are bruised.

Stinking hellebore © Uwe und Lukas, Wikimedia Commons:

The stinking hellebore has been peddled since antiquity as a remedy against all sorts of maladies, but this is what the great British naturalist Gilbert White (1720-1793) had to say about the plant’s medicinal properties:

‘The good women give the leaves powdered to children troubled with worms.’ But he added: ‘Where it killed not the patient, it would certainly kill the worms; but the worst of it is, it will sometimes kill both’.

Like related buttercup or crowfoot plants (Family Ranunculaceae), the stinking hellebore is loaded with toxic glycosides.

Although a bad choice as a worm medicine, the stinking hellebore is an excellent option for a garden. It is one of earliest plants to bloom, which can happen even before the snow has melted away. This is a hard time for bees and other insects because there aren’t many other sources of pollen or nectar, so stinking hellebore flowers can be life savers for emerging bumble bee queens.

Bees may have another good reason to visit these flowers: the warmth generated by yeast metabolism. Stinking hellebore nectaries are colonised by some types of yeast that ferment the nectar and warm the flower to more than 2° C above the ambient temperature. Yeasts have a negative side too: fermentation reduces the sugar content of nectar, which makes the flower less attractive and rewarding to pollinators. We don’t know how these conflicting outcomes pan out for plant and pollinators. Flower yeasts however, seem to be clear winners; they get energy from an abundant supply of nectar, and are dispersed from flower to flower by insects:

Cell formations of Metschnikowia reukaufii, a yeast frequently found in flowers. Bar = 50 μm © Magyar et al., 2005:

Floral warming is an asset for plants with short growing seasons: the extra heat accelerates pollen germination and the growth of pollen tubes, and it leads to heavier seeds and higher germination rates. It may also increase the evaporation of volatile organic compounds, which help in attracting pollinators.

Warm flowers increase insects’ metabolism, boost their flight capability, and encourage them to stick around, basking and foraging. Frequent and long-lasting insect visits are important for upland plants that cannot self-fertilise and rely mostly on flies for pollination. These insects lack pollen-carrying structures and, generally speaking, are much less hairy than bees. So the longer a fly frolics on a flower, the greater the chances it will get pollen grains stuck to it. With luck, some of these grains will be carried to another flower, and pollination will happen.

A warm welcome pays off for plants and insects alike.

Spilogona sanctipauli, a fly from the family Muscidae distributed across the High Arctic and a pollinator of the mountain avens © BoldSystems, Creative Commons.

Readers’ wildlife photos

November 27, 2023 • 8:15 am

Thank Ceiling Cat that readers have responded with some batches of photos for me. But please think of me when you have photos to spare.

Today sees the return of Tony Eales from Oz, and he sent us some photos showing mimicry in insects. Tony’s captions are indented, and you can click on the photos to enlarge them.

On the weekend I went to Black Mountain Nature Reserve in Canberra and was struck by the number and variety of lycid beetle mimics. I’ve brought these up before. The pollen-feeding lycid beetles around here have a distinctive set of grooved brick-red elytra and black head and body and are very foul-tasting if not poisonous.  An extraordinary number and variety of other beetles and insects take advantage of this simple model to avoid predation. The mimicry is often Batesian but also can be Müllerian as with some soldier beetles.

JAC: Remember that Batesian mimicry involves an edible organism mimicking one that is toxic, dangerous, or distasteful, such as the first lycid shown below.  The evolutionary advantage of this mimicry is clear: if you are edible, and a predator has evolved (or learned) to avoid the “aposematic” (warning) color or pattern of another species that for some reason is inedible, you stand a better chance of living—and passing on your genes—if you evolve some aspect of the inedible organisms’s pattern or color. Such mimicry makes you liable to be avoided by the predator more often (the predator will mistake you for an organism it can’t eat). The black-and-orange pattern of the “model” species in the first picture is a typical “warning pattern”, for all lycid beetles are toxic. (Why, by the way, is it advantageous for a species to evolve an easily recognized pattern if it’s toxic, inedible, or dangerous? After all, the first mutant individual with a conspicuous pattern is liable to be picked off by a predator that hasn’t yet learned to avoid it. It would seem, in such a case, that it’s disadvantageous to evolve a conspicuous color or pattern!)

Müllerian mimicry, on the other hand, involves a group of organisms (they need not be related) that are all toxic, dangerous, or distasteful, evolving similar patterns to resemble each other. Can you think of an evolutionary advantage of an insect that’s already inedible evolving a color or pattern resemble another inedible species?

There are also “mimicry rings” that involve a combination of Batesian and Müllerian mimicry. In the cases below, I’m not sure which mimics of the lycid beetles are Batesian or Müllerian.  (By the way, how can we know if a given species of insect is toxic, distasteful, or dangerous? Remember, it has to be so to predators that may attack it in nature, not to us.)  Note that the species below are probably in such a ring, as there are, besides the toxic Porrostoma lycid model, five other beetles and one fly. It’s very unlikely that the fly, at least, is toxic or noxious, and that is surely a case of Batesian mimicry.

Typical lycid beetle Porrostoma sp.:

The Leptospermum or tea-trees in this part of the reserve were beginning to flower and it’s a great time to look for pollen and nectar-feeding beetles and the like. I managed to find no less than three of the four lycid-mimicking jewel beetles in Australia within only a few hundred square metres.

Castiarina rufipennis:

Castiarina erythroptera:

And the fairly rare Castiarina nasuta:

There were also several Washing Beetles, Phyllotocus sp., so called because they often mistake drying white clothes for giant flowers and in season, land on the washing in huge annoying numbers.

And a lycid mimicking click beetle Anilicus sp.:

And best of all I finally found my first lycid-mimicking fly species. The large and beautiful Pelecorhynchus fulvus from the flower-feeding snipe fly family Pelecorhynchidae:

Corpse flower in bloom: live video feed!

November 25, 2023 • 8:36 am

Reader Howie sent me a live feed of a corpse flower  (Amorphophallus titanum, also called “the titan arum”) blooming at Appalachian State, where he teaches.  This is a rare event—the flower opened today in the University greenhouse. The bloom won’t last long: usually about two days, though it could go a few days beyond that.  But it’s best to see it when it first blooms. As Howie noted: “Female flowers mature first, when the smell peaks, followed the next day by the male flowers, with no scent.”  You certainly want to smell how stinky it is, for the smell is part of the way it gets pollinated.

Note that viewing hours are from 6 a.m. to noon, Eastern time, but the feed might continue after that.  First, a photo of the flower, and then a live video:

Here’s Howie’s notes:

These plants, native to Sumatra, engage a special type of respiration, known as thermogenesis, cyanide-resistant respiration, which raises the temperature of the spadix 10-25C above ambient. This volatilizes amines which smell like rotting meat and which attract flies as pollinators.
These plants shuttle electrons in their mitochondria to an alternative oxidase, generating a lot of heat, but no ATP. That pathway is not inhibited by cyanide as is the regular oxidative phosphorylation pathway.
A paper from 2009 by some German researchers suggests the heating also creates convective air currents that further disperse the amines in the otherwise calm air of a tropical forest understory.
It’s a tradition to name your corpse flower, so ours is named Mongo, a twist on our greenhouse manager’s (Jerry Meyer) nickname of Mungo.
I’m going to try and see if I can get false color infra-red photos later today. [JAC: I’ll add them to the post if we get them.]
Voilà: the live feed!

Howie added that they’re having the longest lines ever in the App. State greenhouse:

From Wikipedia:

The titan arum’s inflorescence can reach over 3 m (10 ft) in height.  Like the related cuckoo pint and calla lily, it consists of a fragrant spadix of flowers wrapped by a spathe, which looks like a large petal. In the case of the titan arum, the spathe is a deep green on the outside and dark burgundy red on the inside, with a deeply furrowed texture. The spadix is almost hollow and resembles a large baguette. Near the bottom of the spadix, hidden from view inside the sheath of the spathe, the spadix bears two rings of small flowers. The upper ring bears the male flowers, the lower ring is spangled with bright red-orange carpels. The odor (“fragrance”) of the titan arum resembles rotting meat, attracting carrion-eating beetles and flesh flies (family Sarcophagidae) that pollinate it. The inflorescence’s deep red color and texture contribute to the illusion that the spathe is a piece of meat. During bloom, the tip of the spadix is roughly human body temperature, which helps the perfume volatilize; this heat is also believed to assist in the illusion that attracts carcass-eating insects.

About the blooming:

In cultivation, the titan arum generally requires 5 through 10 years of vegetative growth before blooming for the first time. After a plant’s initial blooming, there can be considerable variation in its blooming frequency. The cultivation conditions are known in detail. Some plants may not bloom again for another 7 through 10 years while others may bloom every two or three years. At the botanical gardens Bonn, it was observed under optimal cultivation conditions that the plants flowered alternatively every second year.  A plant has also been flowering every second year (2012 to 2022) in the Copenhagen Botanical Garden.  Back-to-back blooms occurring within a year have been documented and corms simultaneously sending up both a leaf (or two) and an inflorescence. There has also been an occasion when a 117 kilograms (258 lb) corm produced three simultaneous blooms in Bonn, Germany.  There was also a triplet bloom at the Chicago Botanic Gardens in May 2020 named “The Velvet Queen,” but viewing was closed to the public due to COVID-19.

The spathe generally begins to open between midafternoon and late evening and remains open all night. At this time, the female flowers are receptive to pollination. Although most spathes begin to wilt within 12 hours, some have been known to remain open for 24 to 48 hours. As the spathe wilts, the female flowers lose receptivity to pollination.

And you can read about how stinky it is, too:

As the spathe gradually opens, the spadix heats up to 37 °C (99 °F), and rhythmically releases powerful odors to attract pollinators, insects which feed on dead animals or lay their eggs in rotting meat.[16] The potency of the odor gradually increases from late evening until the middle of the night, when carrion beetles and flesh flies are active as pollinators, then tapers off towards morning.[27] Analyses of chemicals released by the spadix show the stench includes dimethyl trisulfide (like limburger cheese), dimethyl disulfide (garlic), trimethylamine (rotting fish), isovaleric acid (sweaty socks), benzyl alcohol (sweet floral scent), phenol (like Chloraseptic), and indole (like feces).

A National Geographic video, concentrating on the smell:

Here’s a video of one that grew for 11 years before flowering: opening once in a 24-hour period. Talk about the patience of nature!

ADDENDUM:  Reader Bob drove up to see the plant from Asheville and sent a photo and this note:

One of your commenters said he would like to see a close-up of the window they’ve cut out to make the flower parts visible. I’ve attached mine; you’re free to use it if you’d like.

Two additional photos of the flower by Nina Tovish:

 

Readers’ wildlife photos

November 3, 2023 • 8:15 am

Today we have a photo-and-text story about “nectar robbers” by Athayde Tonhasca Júnior. His words are indented, and you can enlarge the photos by clicking on them.

Benevolent delinquents

Christian Konrad Sprengel (1750-1816) is not widely known nowadays, but the German teacher, naturalist and theologian was a pioneer in recognising flowers as lures to insects. Sprengel made significant contributions to our understanding of the role played by insects in plant fertilization, although his writings, published in German, were mostly ignored outside Germany (which is a common fate in the Anglo-centric scientific world). Even still, Sprengel’s discoveries were acknowledged by Darwin in his own work with plants.

A page of Sprengel’s Das entdeckte Geheimniss der Natur im Bau und in der Befruchtung der Blumen (‘The secret of nature discovered in the structure and pollination of flowers’), 1793 © Uwe Thobae, Wikimedia Commons:

Among many novel contributions, Sprengel recorded the ‘outrage against a flower’ played by some bumble bees; they perforate the base of a flower to get access to its nectar, bypassing its opening. From the plant’s perspective, this is cheating. A bee that avoids the flower’s reproductive parts may not pollinate it: the metabolically expensive nectar could be for nothing. This behaviour is known as nectar robbery, a term that reflects a sympathetic bias towards plants; after all, bees – and other insects and some birds as well – are just getting a resource that would be inaccessible otherwise. Most robbed flowers have tubular corollas or nectar spurs (hollow extensions that contains nectar-producing organs) which are out of reach for many visitors, especially bees with short tongues. You can watch them in the act here”.

Nectar spurs on Aquilegia formosa; not reachable by traditional means © Daniel Schwen, Wikimedia Commons:

It has been long assumed, reasonably, that primary nectar robbers (those that perforate the flower to access nectar) and secondary nectar robbers (species that take advantage of existing perforations), are bad: ‘all plants must suffer in some degree when bees obtain their nectar in a felonious manner by biting holes through the corolla’ (Darwin, 1872). Indeed, robbers may reduce the availability of nectar to conventional flower visitors, therefore affecting plants’ reproductive success. Robbers may also destroy floral structures while in the act of breaking in:

A buff-tailed bumble bee (Bombus terrestris) pilfering nectar © Alvesgaspar, Wikimedia Commons:

In Brazil’s Atlantic Forest, the understory shrub Besleria longimucronata is pollinated by the reddish hermit (Phaethornis ruber) and violet-capped woodnymph (Thalurania glaucopis) hummingbirds—that is, if the stingless bee Trigona spinipes is not around. Despite lacking a sting, this bee is quite aggressive, pursuing and biting intruders with its sharp teeth, so that it can perforate the flowers and take their nectar at leisure. Trigona spp. are notorious nectar rustlers throughout the Neotropical region, damaging many wild plants and crops in varying degrees. Those hummingbirds that are not driven away by the bees avoid the nectar-depleted flowers; even worse for the plant, some hummingbird individuals slip into a criminal life themselves and become secondary robbers, taking advantage of the holes created by the bees. As a consequence of the robber’s direct and indirect actions, the shrub suffers a reduction in seed production (Bergamo & Sazima, 2018).

A Besleria sp. shrub, its violet-capped woodnymph pollinator and the nectar robber T. spinipes © Louis van Houtte, Dario Sanches and José Reynaldo da Fonseca, respectively. Wikimedia Commons:

But as is invariably the case in biology, things are more nuanced. Bees tend to stick around patches of rewarding flowers to save energy and forage more efficiently. But if flowers are low in nectar because of robbing, bees are forced to fly longer distances to get what they need. Also, they often spend less time in a given flower and visit more flowers per unit of time to compensate for lower nectar volume. All this shuffling about has a positive outcome for plants: more flowers are visited, more pollen is deposited on stigmas, and outcrossing (mating of unrelated individuals) is more frequent: the end result is increased reproduction and fitness.

Some of these effects were elegantly demonstrated by Mayer et al. (2014) in experiments with potted aconite or monkshood (Aconitum napellus lusitanicum). This endangered herb is pollinated by the common carder bee (Bombus pascuorum), and often robbed by the European honey bee (Apis mellifera). The researchers simulated nectar robbing by removing nectaries from some flowers and estimated pollen dispersal by dabbing anthers with fluorescent dye (a pollen surrogate), which was subsequently searched on stigmas collected from plants placed at some distance from the source. The results: bumble bees visited fewer flowers per plant and spent less time per flower. Also, fluorescent dye from patches with robbed flowers was dispersed over larger distances when compared to dye from control plants that had not been artificially robbed:

A bumble bee making way among the petals of an aconite to get access to its nectar © Franz van Duns, Wikimedia Commons:

And robbers often do more than rob. In northwest Spain, the hairy-footed flower bee (Anthophora plumipes) is the main pollinator of kidney vetch (Anthyllis vulneraria vulgaris), but muggers interfere in this relationship: the buff-tailed (B. terrestris) and the heath (B. jonellus) bumble bees may purloin over 3/4 of all kidney vetch flowers. Despite this rampage, robbed flowers have a higher probability of setting fruit than intact flowers. It turns out that robbers are forced to trample all over the plant’s capitulum (an inflorescence of closely packed flowers), touching anthers and stigmas during the act of thievery, pollinating the flowers (Navarro, 2000).

The heath bumble bee, a nectar robber, stomps around a kidney vetch capitulum, pollinating the flowers © Arnstein Staverløkk and Ivar Leidus, respectively. Wikimedia Commons:

Other studies have confirmed the pollination role of nectar robbers, such as the case of the fuzzy-horned (B. mixtus) and frigid (B. frigidus) bumble bees when visiting tall bluebells (Mertensia paniculata) in Alaska. These two bees pollinate flowers during their early stages of development, when pollen is plentiful, but shift to nectar robbing when nectar becomes abundant later on. But this is not only about a change of diet preferences: older flowers to be robbed of their nectar attract pollinators to young flowers nearby, which means that nectar pilfering aids the pollination of tall bluebells (Morris, 1996):

Tall bluebell flowers are pollinated then robbed, with a positive outcome for the plant © Walter Siegmund, Wikimedia Commons:

Sprengel labelled nectar robbing an ‘outrage against a flower’ and Darwin considered it ‘a felony’, but there’s more to it than meets the eye. Careful investigations have shown that in some cases flower larceny reduces plant reproduction and fitness, but there are many instances of no ill effects on plants, or even beneficial outcomes. It all depends on flower and robber morphologies, insect behaviour, flower density, how much nectar is available, how much of it is taken away, and so on.

‘Robbery’ sounds like a wrench thrown in the mutualistic relationship between plants and pollinators, but the phenomenon is way too common and widespread to be considered an anomaly. And like many other natural events, first impressions can be deceiving: the sight of a flower damaged by a rough visitor is not necessarily a harbinger of harm.

Flowers with punctured corollas, indicating nectar robbing. This could be bad, neutral or good for the plant © Raju Kasambe, Wikimedia Commons:

Readers’ wildlife photos

October 25, 2023 • 8:15 am

As we near the end of my photograph queue, we have a contribution from ecologist Susan Harrison of the University of California at Davis.  Her captions and narrative are indented, and you can enlarge the photos by clicking on them.

Birds on Non-Native (Alien, Invasive, Exotic….) Plants

Non-native species, usually ones introduced from other continents, are often called one of the worst threats to biodiversity, along with habitat loss, overexploitation, and climate change. We all know of terrible examples – kudzu, “the plant that ate the South”;  mammal-swallowing Burmese pythons in the Everglades; the grasses that fueled the Maui fires. There’s a long list of ecologically devastating non-native species (here are 100 of the worst ).

Some conservationists argue that we should make peace with many non-native species and appreciate any benefits conferred by them. Other commentators go further and charge that opposition to non-native species is nothing but xenophobia (a hotly contested viewpoint).  My one concession to this debate has been to shift to more neutral words (introduced, non-native) instead of potentially loaded ones (alien, exotic, invasive).

Birdwatching has sneakily softened my negativity toward non-native plants, however. One recent instance of this involved Sage Thrashers (Oreoscoptes montanus), a jauntily striped, melodious resident  of the Great Basin sagebrush country that has been scarce and evasive in my experience.  What a surprise it was to see veritable flocks of Sage Thrashers at Malheur National Wildlife Refuge, preparing for fall migration by gorging on berries of Russian Olive (Elaeagnus angustifolia) — one of the most hated non-native plants in U.S. deserts.  In a five-day period, I never saw these birds eating anything else.

Here are some Sage Thrashers eating Russian Olives:

You can readily get Californians arguing over “the great Eucalyptus debate” – whether these towering and widely-planted Australian trees should be protected or eradicated. Our riparian bird hotspots in Davis, California have Eucalyptus (mostly River Red Gum, Eucalyptus camaldulensis) mixed in with the native Valley Oaks (Quercus lobata), California Walnut (Juglans californica) and other trees.   It’s been a surprise to me how much native birds use Eucalyptus.

Black-headed Grosbeaks (Pheucticus melanocephalus), Bullock’s Orioles (Icterus bullocki), Western Tanagers (Piranga ludoviciana), and various warblers feed on lerp psyllids (Glycaspis brimblecombei), sap-sucking insects that arrived here from Australia in 1998.  Red-breasted Sapsuckers (Sphyrapicus ruber) skip the lerp psyllids and feed directly on Eucalyptus sap after drilling into the trunk.  The height of Eucalyptus trees makes them favored nest sites for raptors such as Great Horned Owls (Bubo virginianus).

Black-Headed Grosbeak on Eucalpytus:

Red-breasted Sapsucker on Eucalpytus:

Eucalyptus with lerp psyllids on leaves and sapsucker damage on trunk:

Great Horned Owl nest with nestling:

Here are birds using some other much-despised non-native plants at the local creek:

Lesser Goldfinch (Spinus psaltria) on Yellow Star-Thistle (Centaurea solstitialis):

House Finches (Haemorhous mexicanus) on Salt-Cedar or Tamarisk (Tamarix chinensis):

Savanna Sparrow (Passerculus sandwichensis) on Black Mustard (Brassica nigra):

At home, while I’ll continue dutifully planting the yard with natives, I confess to sometimes envying the abundance of birds on the neighbors’ ornamental plants.

Cedar Waxwings (Bombycillus cedrorum) on Cotoneaster (Cotoneaster):

Western Tanagers on Pear (Pyrus):

Readers’ wildlife photos

October 17, 2023 • 8:15 am

Today we’ll have part 2 of Robert Lang’s photos of the wildflowers of Southern California (part 1 is here). You can click on the photos to enlarge them, and Robert’s text and IDs are indented.

California wildflowers, Part 2

Continuing this series of wildflowers from Southern California’s unusually wet winter and spring in early 2023. Most of these photos were taken in June.

California is assuredly not the Buckeye State, but we do have our own California Buckeye (Aesculus californica). The Native American tribes used the poisonous nuts and seeds to stun fish in streams and ponds, but the seeds could also be prepared in a way that leached the toxins out, allowing them to also be used as a food source:

The Hoary Rock-Rose (Cistus creticus) has large, delicate flowers that often have a slightly rumpled appearance. They were blooming in June this year, but (presumably due to the damp weather) they are already starting to produce new blooms here in October:

A related plant, not native to Southern California, is the Gum Rockrose (Cistus ladanifer), which has large white flowers. Not all flowers have the five maroon markings seen here, and those without are sometimes mistaken for the local Matilija Poppy (Romneya sp.):

My studio is on the border of two communities: Coastal Sage Scrub (typical of the lower canyons) and Chaparral (which climbs up the mountainside). The chapparal consists of a mix of plants, which changes with elevation; after several hundred feet of elevation gain on the local trails, I start to see Yerba Santa (Eriodictyon californicum) coming into the mix:

There are patches of Prickly Pear (Opuntia sp.) in both the Coastal Sage Scrub and Chaparral plant communities, both native varieties and introduced (presumably garden escapees). Their flowers are huge and gorgeous, but not very long-lived:

Another “prickly” plant (though not a cactus) is the California Prickly Phlox (Linanthus californicus), which forms brilliant balls of purple or magenta flowers. Like Yerba Santa, I only see this higher up in the San Gabriels:

Widespread in both communities is the Whipple Yucca (Hesperoyucca whipplei). They only bloom once, then die, typically sending up their shoots in June. The number varies from year to year; in a good year, the mountainsides appear to be covered in candles:

Perhaps the most famous California flower—and the state flower—is the California poppy (Eschscholzia californica). In the early days of European settlement of this region, Altadena was famous for its fields of poppies, which were said to be visible from ships off the coast, some 20 miles away. Sadly, the golden poppy fields were replaced by housing developments (well, not too sadly, since one of those houses is now my studio), but we can still find patches of poppies up on the trails:

Most California poppies are bright orange, but there is considerable variation in color; here are two of the varieties growing side-by-side along the Lower Sam Merrill Trail:

I’ll end with one colorful orange plant that isn’t a flower: the California Dodder (Cuscuta californica), which has no visible leaves (they’re there, but reduced to almost nothing) and no chlorophyll; it parasitizes other plants. Although the dense tangles like this one appear to be smothering the host plant (California buckwheat (Eriogonum fasciculatum) is a common host around here), the dodder dies off over the summer, and the host plants come roaring back the next spring, and the cycle starts again:

Readers’ wildlife photos

October 16, 2023 • 8:15 am

Please send in your photos. Do I have to beg? Very well, I beg!

Today’s photos come from Robert Lang, reader, physicist, and origami master. This is part 1 of a two-part series on California wildflowers. Robert’s narrative is indented, and you can enlarge the photos by clicking on them.

California wildflowers, Part 1

As you may have read in the news, California had an unusually wet winter and spring, and then in Southern California, we had a cool, overcast June. The result was to stretch out the wildflower season and bring out some of the ones I don’t usually see on the trails behind my studio. Most of these are natives, but there are a lot of introduced Mediterranean-climate flowers along the urban/wildlife edge, some of them rather nastily invasive.

(I took most of these in June. It’s now fall [October], and although the winter rains haven’t seriously started, a few small storms during the summer have kept water in the canyons and this year’s wildflowers are already starting to come out.)

California brittlebush (Encelia californica), also called bush sunflower, provides a cheerful sunny site along the trail:

Caterpillar scorpionweed (Phacelia cicutaria) is so named because after it blooms, the flower stalks look like little caterpillars (and they are curled like a scorpion’s tail). They don’t sting, however. The locals just call it “caterpillar bush,” and when the flower stalks fall off of the plant, they do look like little caterpillars crossing the trail:

Here’s what they look like post-blooming:

There  are several varieties of sage in the low chapparal, the most common being California black sage (alvia mellifera), California white sage (Salvia apiana) (which is getting less common due to poaching by collectors), and this variety, chia sage (Salvia columbariae). Yes, it’s the same “chia” that is used on “Chia pots” sold on late-night TV. Chia was an important part of the indigenous Tongva people’s diet:

Clearwater Cryptantha (Cryptantha intermedia) is not so common, but has lovely tiny white flowers:

Large-flowered Phacelia (Phacelia grandiflora) is related to “caterpillar bush,” but, as the name suggests, their flowers are larger (and less caterpillar-like). (This plant is an earworm: I cannot read or say the name “Phacelia” without a Simon and Garfunkel beat coming into my head):

There are quite a few varieties of paintbrush (Castilleja sp.) in the area. I can’t tell the various species apart. They’re all pretty:

The many pistils in Pipestem Clematis (Clematis lasiantha) give it a feathery appearance:

Southern Bush Monkeyflower (Diplacus longiflorus) is sensitive to touch; the stigma closes up after touching, so that once it’s pollinated, bees know to move on to the next flower:

And finally for this batch, an invasive. Spanish Broom (Spartium junceum) is native to the Mediterranean, but is widespread in Southern California, particularly along the edges of trails and roads (like many invasives, it is particularly successful in disturbed habitats). In early summer, it is covered in fragrant, almost pungent, blooms, and walking down the trail is like walking into one of those mall candle shops, so powerful is the odor:

Coming in part 2: more flowers.

Readers’ wildlife photos

October 14, 2023 • 8:15 am

Today’s story-plus-picture piece, with a very cool story on pollination, comes from Athayde Tonhasca Júnior, whose notes are indented. Click on the photos to enlarge them.

Master manipulators

When the headmaster of a German grammar school became ill because of problems with unruly students, their well-off parents and school supervisors, his doctor recommended the study of nature to relax and deal with stress. This scenario would be painfully familiar to many teachers today, but the headmaster in question was Christian Konrad Sprengel (1750-1816), who took up the doctor’s advice and became one of world’s greatest botanists (Zepernick et al., 2001). Among many contributions, Sprengel proposed that the main purpose of flowers was to attract insects for achieving sexual reproduction via pollination. Sprengel also discovered that some orchid flowers lure pollinators without offering pollen, nectar or any other reward. In other words, those orchids rely on deceptive Scheinsaftblumen, ‘sham nectar flowers’.

A commemorative stone in Berlin’s Botanical Gardens, based on the frontispiece of Spengel’s seminal work on plant reproduction © Rüdiger, Wikimedia Commons:

Sprengel’s idea of deceptive flowers didn’t settle well with contemporary fellow naturalists, who maintained that the diversity and abundance of angiosperms (flowering plants) depended on their mutualistic relations with pollinators; any cheating would pull to pieces these fine-tuned interactions. Darwin wrote that anyone who believed in ‘so gigantic an imposture’ must ‘rank the sense or instinctive knowledge of many kinds of insects, even bees, very low in the scale’. But it turns out that insects do fall for impostures; an estimated 4 to 6% of all flowering plants use some form of trickery to lure pollinators. They most commonly do that by food deception, falsely advertising pollen or nectar by their flowers’ shape, colour, scent, or pollen-like structures. Plants can also resort to sexual deception, when flowers look or smell like female insects, luring males to a non-existent partner, or some other ruse.

Orchids are famed cheats; about one-third of the roughly 28,000 known species attract pollinators with a variety of subterfuges, giving back nothing. But despite their intricate adaptations to mislead pollinators, orchids are amateurs when compared to sophisticated schemers in the plant world such as the parachute or umbrella plant (Ceropegia sandersonii, family Apocynaceae), a native of southeast Africa and a houseplant elsewhere.

A parachute plant © Wouter Hagens, Wikimedia Commons:

When a European honey bee (Apis mellifera) approaches a flower, it risks being pounced upon by a predator, especially crab or flower spiders. If the bee is not alert or fast enough, it will find itself in the spider’s palps. The ensnared bee releases defence pheromones (volatiles that elicit a reaction from members of the same species) to alert sister bees. Those chemicals can also be picked up by another creature altogether: a jackal fly, aka freeloader fly (family Milichiidae). Some of these small, dark, widespread but poorly known flies are kleptoparasites – ‘parasites by theft’, which steal food from another animal, like frigate birds and hyenas. As the spider’s lunch struggles hopelessly to free itself, jackal flies come out of nowhere to land on the bee and feed on the substances oozing from its body – they possibly also pierce the honey bee ‘skin’ (exoskeleton) to get its juices. You can watch them in action here. If the jackal flies don’t respond quickly to the bee’s chemical cues, they will miss the opportunity to get their share before the spider finishes its meal.

A honey bee having a bad day: captured by a crab spider, it releases alarm pheromones and other volatiles that attract jackal flies © JonRichfield, Wikimedia Commons:

In a remarkable selective twist, flowers of the parachute plant produce a mixture of chemical compounds that include some of the very volatiles released by European honey bees when they bite or sting to defend themselves against attackers. Such chemicals are not going to entice bees or most other pollinators to visit the flowers, but they are irresistible to jackal flies. As it turns out, these flies are the main pollen carriers of the parachute plant (Heiduk et al., 2016). This chemical stratagem seems overly elaborate, but the parachute plant is not alone is deploying it.

The round-leaved birthwort or smearwort (Aristolochia rotunda) is a herbaceous plant native to Southern Europe. Oelschlägel et al. (2015) discovered that its flowers release volatiles of the type found in other angiosperms, but also some chemicals identical to those produced by true bugs of the family Miridae when they are attacked by spiders, ants, praying mantis or any predator fancying a juicy meal (while the term ‘bugs’ is used for insects in general, true bugs are insects in the order Hemiptera: cicadas, aphids, leafhoppers, shield bugs, etc.). ‘Volunteer’ mirid bugs squeezed with a forceps quickly attracted flies, most of them frit flies (family Chloropidae). And just like the jackal flies, these frit flies are kleptoparasites: they feed on – you may have guessed it – on the exudates of dying or freshly killed bugs. And crucially for our tale, frit flies are drawn to the flowers of round-leaved birthwort in its natural habitat and end up carrying away nearly 90% of the pollen produced.

L: a round-leaved birthwort flower © Kenraiz, Wikimedia Commons; R, top: the frit fly Trachysiphonella ruficeps carrying round-leaved birthwort pollen on its head and thorax; R, bottom: T. ruficeps flies mobbing a freshly killed Capsus ater mirid © Oelschlägel et al., 2015:

Almost all known Aristolochia species use deception and are myophilous (pollinated by flies); more specifically, these plants rely on either sapromyophily, pollination by flies that are attracted to the scents of dead animals or dung, or micromyiophily, pollination by the smallest flies. The authors of the birthwort study proposed a new term to describe pollination carried out by kleptoparasitic flies: kleptomyiophily (you may wish to keep these and other pollination syndrome terms handy to ace your next Scrabble match).

The parachute plant and the round-leaved birthwort dupe their kleptoparasitic pollinators with smells, but the rare Ceropegia gerrardii (family Apocynaceae) from eastern South Africa made things a bit fancier. Instead of scents alone, its flowers secrete a liquid containing protein and sugars which is similar to the ‘blood’ (haemolymph) of injured honey bees and other insects. These ‘bleeding flowers’ are irresistible to jackal flies hoping to find a vulnerable, dying honey bee – so in this case, pollinators are rewarded. The combination of scent and free ‘blood’ encourages the flies to stick around and feed for longer, thus increasing the chances of pollen contamination. And the trick seems to work: among all visiting flies, almost all pollen carriers were females of four kleptoparasite species in the genus Desmometopa (Heiduk et al., 2023).

(a) C. gerrardii flower with droplets secreted by the corolla lobes; (b) a corolla lobe covered with secreted liquid; (c) fly ready to remove or deposit a pollinarium; (d) fly lapping the secreted liquid; (e) fly holding a blob of secretion. Arrows in (d) and (e) indicate a pollinarium attached to the fly’s mouthparts. Bars: (a) 5 mm, (b) 2 mm, (c) 0.6 mm, (d) 0.3 mm, (e) 0.4 mm © Heiduk et al., 2023:

It would be worth a moment to appreciate the plants’ achievements in resorting to deception by kleptomyiophily. They don’t rely on flowery bouquets or sexual decoys, which may trick run-of-the-mill visitors that may have questionable pollination abilities. Instead, by mimicking the chemical signature of doomed insects, these plants manage to dupe a cohort of fast-responding, highly specialised and efficient pollinators that otherwise would have no interest in visiting their flowers. It’s had to beat that for cunning manipulation.

JAC:  As Leslie Orgel said, “Evolution is cleverer than you are.”  This is an amazing series of evolutionary tales—and appropriate for Halloween.