Category: insects and other arthropods

Readers’ wildlife photos

May 24, 2025 • 8:15 am

Today we have a diverse set of photos from Amy Perry of Indiana. Amy’s captions and IDs are indented, and you can enlarge her photos by clicking on them. After this we have only one batch of photos left.

All photos were taken at Ritchey Woods, a state-designated nature preserve owned by the city of Fishers, a suburb of Indianapolis. The preserve is surrounded by commercial and residential development and an airport and is a treasured haven for families, dog walkers, runners, and birders and other nature lovers. The majority were taken with my iPhone 11 in the past year; a few plant photos were taken by the park naturalist, probably with her iPhone around 2019.

Common box turtle (Terrapene carolina) sitting just as royally as you please on a bridge:

Insects mating. Haven’t been able to identify the species [Readers?]:

Milkweed tussock or milkweed tiger moth caterpillar (Euchaetes egle) on, unsurprisingly, milkweed, probably Asclepias syriaca:

Trout lily (Erythronium americanum). Spring ephemeral. Also called yellow adder’s tongue and yellow dogtooth violet. One of the few yellow spring ephemerals, in my experience. Most are white. Spring ephemerals bloom before the tree canopy leafs out, as they take advantage of the sunlight that the trees block after the leaves appear:

Dutchmen’s Breeches (Dicentra cucullaria). Spring ephemeral:

Shagbark hickory (Carya ovata). I like species that have an obvious identifying characteristic, such as the shaggy bark here. It’s a bonus if the common name and/or Latin name also reflects the identifying characteristic:

Spring beauty (Claytonia virginica). These beauties carpet the forest floor during April. The pale pink stripes are said to guide insects to the nectar or pollen. The blooms close if the temperature goes below 45 degrees F. Spring ephemeral. I just learned that another common name is Fairy spud, which seems apt:

More spring beauty, to show the attractiveness of their natural massed growth. They are at the foot of a sign marking a border of the nature preserve:

Skunk cabbage (Symplocarpus foetidus). This is the spathe. Grows in January and February in moist soil. Sometimes the energy radiated by the growth actually melts the surrounding snow or ice. True to its name, it has a strong, unattractive odor:

Virginia bluebells (Mertensia virginica). Often the blossoms are pink when they first bloom and then turn a lovely blue. Spring ephemeral:

Callery pear (Pyrus calleryana). Ending on a depressing note. These trees have a lovely oval shape but are invasive. Also called Bradford pear.  This species is not on the state’s official invasive list, but plans are in the works to have it added soon. The official invasive list prohibits the sale, purchase, transport, or giving of invasive species within the state. When several species were added a few years ago to the list, this one was discussed, but so many nurseries had it “in the pipeline,” that conservationists decided to take a small victory and wait to add it later:

Readers’ wildlife photos

May 5, 2025 • 8:15 am

Today we have another photo-and-text essay from Athayde Tonhasca Júnior, featuring another introduced insect from Japan.  Athayde’s captions are indented, and you can enlarge his photos by clicking on them.

AND. . .special kudos for Athayde, for he noted this:

If I’m correct, this will be my 100th contribution to WEIT. As we all make a fuss about 100 (is it because it marks the boiling point of water?), I thought it would be worth mentioning it. 

That’s a lot of education he’s given us over the years, so thank you, Athayde!

***********

Menacing tenants

In an apple orchard somewhere in the American state of Pennsylvania, an adult Japanese horn-faced bee (Osmia cornifrons) has just emerged from its nest and makes its way into the big wide world. The apple grower has high hopes for that bee; in fact, he bought many of them when they were still inside their cocoons. The Japanese horn-faced bee was introduced from Japan in the 1970s, and since then it has been widely used in the Eastern United States to improve the pollination of apples and other fruit trees such as peaches, pears and cherries.

A female Japanese horn-faced bee © Chelsey Ritner, Exotic Bee ID:

In their natural habitats, the Japanese horn-faced bee and similar species nest inside cavities such as hollowed reeds, tree holes and cracks in stones. Females use a range of materials, especially mud and pebbles, to build individual nest cells in which they lay an egg. When bees are done, they seal off the nest entrance with mud – so they are known as mason bees. Fruit growers offer bees nesting alternatives such as drilled blocks of wood or bunches of cardboard tubes tightly packed together.

Two types of mason bee nests used in orchards: cardboard tubes (a) and wood blocks (b) © Kline et al., 2023:

The future seemed promising for that Japanese horn-faced bee in Pennsylvania. But opportunists were on standby, ready to pounce when an unsuspecting bee leaves its nest. In the blink of an eye, a gang of hypopi (singular hypopus) jumps on the bee, holding on for dear life as their ride flies away.

Hypopi, also known as hypopodes, are a special nymphal stage found in some mites. In this case, the hairy-footed pollen mite (Chaetodactylus krombeini). Hypopi have no head or mouthparts, but are armed with special structures for hanging on; either powerful claws or a sucker plate to glue themselves to their host. These adaptations greatly facilitate phoresis, which is when an organism attaches itself to another for the purpose of transportation. Phoresis is typically found in small and poorly mobile organisms such as nematodes and mites. But curiously, the hypopus stage is usually facultative for mites; it occurs only when conditions deteriorate (food scarcity, overcrowding, dry climate, etc.), so that skedaddling increases the likelihood of survival.

A hypopus, the stage adapted for phoresis © Reynolds et al., 2014:

The departing bee has no chance of avoiding the lurking hitchhikers who react instantaneously to the slightest touch to their dorsal setae (bristles) or to air movement caused by a passing body. And the feats of some of these mites defy credulity; the tiny Histiostoma laboratorium (formally known as H. genetica), a scourge of vinegar fly (Drosophila melanogaster) laboratory colonies, lurches into the air to grab fruit flies flying above them (Hall, 1959. J. Kansas Entomological Society 32: 45-46). Some species that have hummingbirds as hosts rush to the birds’ nostrils at a rate of 12 body-lengths per second, which is a speed proportional to a cheetah’s (Colwell, 1985)

Hypopi attached to their host © D.E. Walter, Invasive Mite Identification, Colorado State University and USDA/APHIS/PPQ Center for Plant Health Science and Technology:

After being mobbed by hypopi, the bee carries on with its life. If it’s a female, she will mate and start a nest of her own. When her brood cells are ready, her unwanted companions come out of their lethargic state, jump off and resume their development, maturing and reproducing quickly, all the while feeding on the pollen and nectar gathered by the bee. When their numbers reach certain levels, they may feed on the bee’s eggs and larvae (details are sketchy). In a few months the mites may reach thousands and overrun the brood cell, leaving space for nothing else.

Hairy-footed pollen mites inside a mason bee nest cell © Pavel Klimov, Wikimedia Commons.

Such massive numbers of kleptoparasites (organisms that steal food from another one) spell serious trouble for Japanese horn-faced bees; their eggs and larvae die or develop poorly for lack of food or direct attack from mites. Some adult bees may not even have a chance to start a new family; they are so burdened by mites that they cannot fly. They fall to the ground and become easy pickings for ants and other predators.

A mason bee loaded with pollen mites © GeeBee60, Wikimedia Commons:

Several mason bee species are susceptible to the hairy-footed pollen mite, but managed Japanese horn-faced bees have been hit particularly hard, with losses reaching up to 50% of the population. It’s not difficult to understand why. The same way crowded slums make people more vulnerable to all sorts of diseases, jam-packed nests increase the chances of mites passing from one bee to another. And the hairy-footed pollen mite does not even depend on phoresis: adults can walk from one nest to another nearby, getting inside through holes in the sealing mud made by parasitic wasps. To make the situation worse, this mite can turn into a dormant stage that survives several years inside an empty nest, rousing back to activity as soon as new tenants arrive.

The effects of the hairy-footed pollen mite on the Japanese horn-faced bee are a reminder of the unintended consequences of well-intentioned actions. Bee houses or bee ‘hotels’ have been promoted as enhancers of wild bee populations, but there’s no indication of such effects. They do however increase the risk of pathogens and parasites: not only mites, but a range of fungi, parasitic flies and wasps bedevil mason bees (Groulx & Forrest, 2017).

A bee hotel: not such a great idea © Colin Smith, Wikimedia Commons:

American fruit growers do their best to keep mites under control by replacing the nesting tubes yearly, sterilising wood blocks, or removing and storing bee cocoons during the winter. If you have a bee house but don’t have the resources, time or inclination to do the same, you should follow Colin Purrington‘s advice: buy a garden gnome instead.

Readers’ wildlife photos

May 1, 2025 • 8:15 am

Mark Sturtevant has a passel of insect and arthropod photos for us today, with one plant at the end. His captions and IDs are indented, and you can enlarge the photos by clicking on them.

This set of pictures is from an outing that I’d taken to the Indiana Dunes National Park and surrounding area. I had gone there to meet up with some of my own tribe – people who are as obsessed as I am about macrophotography. I had arrived a day early to wander about on my own at some area parks, and then the 2nd day was spent with people who are almost as odd and “buggy” as I am. It was magical!  The pictures here are more or less in chronological order.

First up is a scene from a small commotion on a sandy trail. The beetle is a Wedge-shaped beetle, Macrosiagon limbata, fighting for its life as it is being carried away by an ant. Now identifying ants is a significant weakness of mine, so I don’t know what this one is. I did not interfere, although I wanted to:

Next up is a Common Buckeye, Junonia coenia. My gear is well designed to allow some versatility when out in the field. This picture was taken with my full frame camera and 400mm lens (although at close range), while the previous picture was taken with a crop sensor camera and a 100mm macro lens with its magnification boosted by a Diopter clip-on lens. It takes only a few seconds to switch between rigs as I carry them hands-free with a modified harness:

Next up is a Rose Chafer Beetle, Macrodactylus sp.:

I found this pair of Greenhouse Millipedes, Oxidus gracilis, on a tree trunk. I believe the male (on top) is doing mate guarding. That is, the female is already inseminated, and he is making sure that other males will not usurp his genetic future:

The sandy trails in the Dunes National Park had numerous smaller examples of Velvet Ants (Dasymutilla). These are actually wasps, although the females are wingless and they grow up as parasites on ground-nesting Hymenoptera. The picture here is a bit of a bucket list item for me. Velvet Ants are famous for their extra long stingers and notoriously painful stings, so I bought a pair of forceps just for this picture since I knew in advance that they would be common in the park. So here I am carefully holding a very angry Velvet Ant in order to photograph that impressive weapon! The only disappointment was that this was not the significantly larger species known as the “Cow Killer”. I have not seen one of those for many years. The wasp is not being injured btw, since their thorax is exceptionally hard. Insect collectors discover that when they try to put a pin through them, only to discover that it ain’t going to happen:

Having joined with the other group of macro photographers, we made our way to a nearby field. Here is a Monarch Butterfly, Danaus plexippus:

Next up was a super exciting find for me. The butterfly is the melanistic form of the Eastern Tiger Swallowtail (Papilio glaucus). This is a classic example of Batesian mimicry, when a harmless species mimics an unpalatable model. In this case, the model species is the toxic Pipevine Swallowtail, which ranges well south of where I live so I don’t normally see the melanistic tiger or its poisonous model. As this was only the third time I’d seen this variety of Tiger Swallowtail, I was absolutely giddy with excitement, much to the amusement of my new-found friends who see these butterflies all the time:

Next is another example of the same form of mimicry. The insect here is a Thick-headed Fly, Physocephala tibialis, which is a mimic of a Mud-dauber Wasp, right down to having a narrow waist and appearing to have long wasp-like antennae by mounting shorter antennae on a stalk on the head. The larvae of these flies grow as internal parasites inside adult bees, usually bumblebees. I do sometimes see moribund or dead bumblebees, and possibly some of these have the pupa of one of these flies inside them:

I did not intend to give lessons in mimicry, but the insect shown in the next picture is an example of a different kind of mimicry known as Müllerian mimicry. This is where different species that are not good to eat have evolved to mimic each other. The insect is an End-banded Net-winged Beetle, Calopteron terminale, and it is part of a complex of Müllerian mimics that include other species of beetles in the same genus, plus beetles in various other families, and possibly Hymenopterans for good measure:

Finally, the host of our gathering showed us a Special Place on their property where an interesting plant grows year after year. These are Indian Pipes, aka Ghost Pipes, Monotropa uniflora. Indian Pipe plants lack photosynthetic pigment, and they survive as parasites on the root systems of trees.

Readers’ wildlife photos

September 23, 2024 • 11:30 am

Today’s photos come from Uwe Mueller in Deutschland. Mueller’s captions and IDs are indented, and you can enlarge the photos by clicking on them:

Here is a collection of insects that I shot in the Bergisches Land of Germany. I’m not that familiar with insects so it is possible (in fact very likely) that I committed errors with their naming. Any corrections will be appreciated.

A Globe wanderer dragonfly (Pantala flavescens) that landed on my balcony and didn’t mind when I took multiple shots of her from close proximity. According to Wikipedia it can be found all around the globe but is quite rare in Europe and made its first appearance in Germany only in 2019.

A Migrant hawker (Aeshna mixta) in flight. These is one of the main dragonfly species that I see at our local pond. Its german name is Herbst-Mosaikjungfer which translates to Fall mosaic virgin, whatever the reason behind this name is:

A Western honey bee (Apis mellifera):

Not too sure if this is a Common wasp (Vespula vulgaris) or a German wasp (Vespula germanica). On another shot I could see one dot on its head. According to Wikipedia the German wasp should have three dots so I guess it is the Common wasp then:

A Polygonia c-album which I find is a strange name for a butterfly:

Another insect that I wasn’t able to identify. Some kind of predatory fly that is eating another insect:

An ant (Tetramorium noclueensis):

An insect identification website told me that this is a fruit fly (Drosophila sp.). However, is it? I shot this in our local forest and the fruit flies that I sometimes find in my kitchen during the fruit season are usually a lot smaller:

Readers’ wildlife photos

July 19, 2024 • 8:15 am

Saved by the bell, I have two or three batches of photos left. Today we have arthropod photos from one of our most regular contributors, Mark Sturtevant. Mark’s captions and IDs are indented, and you can enlarge his photos by clicking on them.

Here are more pictures of arthropods from the previous summer. They were taken from the area where I live: in eastern Michigan.

I regularly check out our “sun garden” in the backyard to see what is going on, and there I commonly find small herds of Boxelder Bugs (Boisea trivittata) as shown with this group of nymphs. Boxelder Bugs feed on the developing seeds of various trees, not just Boxelder trees, and their bright colors are a signal that they are chemically protected. The winged adults will seek shelter for the winter, and this will include peoples’ homes, so during the winter they will turn up in the house along with overwintering stink bugs and ladybird beetles. But I don’t mind buggy visitors during the long winters:

Next up is a Caddisfly. Caddisflies are a sister taxon to Lepidoptera, but their larvae are usually aquatic. They can be hard to identify, and so I can suggest only that this is in the genus Banksiola because it sure does look like it. This won’t be the only time that my IDs’are uncertain here:

The next two pictures show Wooly Aphids, aphids that secrete a waxy floof for protection. I have no idea about their identity, although it would help if I remembered their host plant. The colony picture shows nymphs, winged males, and wingless females. It was rather disgusting:

We come next to a kind of beetle that has become a bit of an obsession. This is one of the species of gold Tortoise Beetles, so-named for its lovely metallic gold color. The particular species here is Deloyala guttata.  There is a similar one that I also find that can be pretty much all gold but when even slightly disturbed it rapidly turns a plain orange color so that it resembles a toxic ladybug.  This picture also marks a first attempt to add some digital brush work and other enhancements to the surroundings during post-processing. I commonly see this sort of thing in the hobby, and I would now like to dabble in this trickery from time to time:

Both of our local species of gold Tortoise Beetle feed on the leaves of Morning Glory plants and related species. As lovely as the beetles can be, their larvae and pupae are decidedly the opposite. Next is a picture of one of the pupae, and the larvae are similar. One of course notes the icky mass that is held over the back. That is a repellant collection of their poo and cast skins, and is called a “fecal shield”. If you want to find golden Tortoise Beetles, look on Morning Glories or on related plants like Bindweed. Swiss-cheese holes in the leaves are a sign of the larvae, and there is a fair chance that a sparkly adult or two is hiding under a leaf. But be quick, as the adults are very shy.

Next up is a tiny weevil, which I believe to be Conotrachelus sp. It just sat there, locked in this pose, while did a focus stack:

The wasp shown in the next picture is a parasitic Ichneumon wasp, Therion sp. I don’t know what hosts are used by this one, but I do know that a related species will parasitize caterpillars:

If I have a special treat, I like to put it in last and so here it comes. Besides tortoise beetles, I have lately become very interested in the little cobweb building comb-footed spiders (family Theridiidae), especially because their habits are greater than what I had supposed. Familiar examples of spiders in this family include what we call House Spiders in the U.S., and then there are the Widows. As you all know, these more familiar species favor dark places where they sit and wait to ensnare prey that encounter their tangled-looking cobwebs (although their webs actually have some clever designs to them). But the family is large, and Theridiids don’t all lurk in dark places, nor do they all simply stay in a web to wait for prey to come to them.

See this little spider? Rather pretty, isn’t it? This is the Candy-striped spider (Enoplognatha ovata). The picture is a staged manual focus stack of a spider that had wandered on its own onto our back porch. The “sky” is really a paint swatch. The 2nd picture shows a male in our sun garden:

Well, this little spider is a notable marauder of diurnal (daytime active) insects, and it uses different strategies to hunt prey. Candy-striped spiders make small tangled webs near the tops of plants in gardens and fields, and there they aggressively go after insects that so much as touch their web. More recently, I got to watch one of these spiders, lurking below a flower, attack a much larger bee that happened to be foraging on the flower above. The bee had no chance as the spider steadily thrusted loop after loop of silk up from between the petals of the flower, pinning the bees’ feet down. I have pictures to show later – they are still in the camera.

It doesn’t stop there, though. According to this beautifully done research paper, and summarized further in this article, the spiders become even more pro-active hunters under the cover of night. Diurnal insects often sleep up on plants at night, and that is when the little spiders can venture out and blindly explore the plants around them in order to murder insects in their sleep and eat them. It is through this active hunting that a high percentage of their prey are bees and wasps, and the size of the insect affords them no protection. The research paper has a fabulous picture that made the journal cover that conveys the carnage rather well. Y’all really should zoom in on that journal picture to appreciate the horror of it.

So now I am regularly examining the foliage around plants, looking for small, innocent-looking cobwebs. Just this morning I found another one of these spiders sitting on top of a daisy in the sun garden, eating a Hemipteran –like flower crab spiders do. Last summer and again this summer, I am finding hints that at least a couple other Theridiid species may use similar sneak-outside-of-their-web strategies. In iNaturalist there are quite a few pictures of brightly colored spiders in this family that are just sitting around in the open, without tangled webs. So what are they up to? And here is this little Theridiid (Theridion frondeum) in a park near Detroit. She was tucked away in a leaf, and no web was nearby. So how did this nearly blind spider bring down this big fly? As always, there are more questions:

Readers’ wildlife photos

June 24, 2024 • 8:15 am

I am still running low on photos, though I have a handful of contributions, and would greatly appreciate any readers sending in their good photos. Thanks!

Today we have a text-and-photo natural history and medical lesson from Athayde Tonhasca Júnior; his narrative is indented and you can enlarge the photos by clicking on them.

Suspicions and proofs

From a hundred rabbits you can’t make a horse, a hundred suspicions don’t make a proof (Fyodor Dostoyevsky)

Few people contributed more with entries to medical dictionaries than renowned German physician, anatomist and pathologist Friedrich Gustav Jacob Henle (1809-1885): Henle’s fissure, Henle’s layer, Henle’s ligament and Henle’s tubules are some of the several terms named after him. But there’s more from the good doctor: in a 1840 paper quirkily titled Von den Miasmen und Contagien (On Miasmas and Contagions), Henle championed the theory that microscopic organisms caused diseases, which was questioned by his peers. Later, Henle proposed the necessary steps to prove the theory, such as detecting the suspected agent in every case of the disease and establishing its absence in healthy people. These ideas were refined by Henle’s most famous student, Robert Koch (1843-1910), a future Nobel laureate, and are known today as the Henle-Koch postulates – although often, and unfairly, called just Koch postulates. These guidelines hold that the suspected microorganism must be present in every host affected by the disease but absent in healthy organisms; the microorganism must be isolated from a contaminated host and grown in a culture; the cultured microorganism should cause the disease when inoculated into a healthy organism; and the microorganism must be isolated again from the inoculated organism and identified as being identical to the original agent.

Dr Henle helped debunk the belief that diseases were caused by miasma, or bad air. Image in the public domain, Wikimedia Commons.

The original Henle-Koch postulates are no longer universally applicable because we learned quite a lot since they were formulated: for example, many pathogenic organisms are regularly found in healthy hosts, and the rules are not valid for viruses, which had not yet been discovered. Nonetheless, the postulates gave a rigorous scientific foundation to the emerging field of medical microbiology. By establishing a reliable causal relationship between microorganisms and infectious diseases, doctors could explore options for prevention and treatment.

Drs Friedrich Henle and Robert Koch were entitled to be proud of their work, but they probably would have been surprised to learn that their postulates are also relevant in the field of pollination ecology.

Pollination is the fundamental mechanism of plant reproduction. Since plants can’t go out on a date, they need an agent to transfer pollen for them. For nearly 90% of all wild flowering plants, this work is done by animals, mainly insects. And considering that more than 75% of the world’s most important crops benefit in some degree from animal pollination, identifying pollinating agents is enormously important for the economy and humanity’s well-being.

The apparently obvious way of recognizing pollinators is by checking out which creatures visit flowers. However, it has long been known that an insect or any other animal landing on a flower does not necessarily contribute to its pollination. Some visitors are nectar thieves: they take the flower’s nectar without touching stigmas or anthers. Others are nectar robbers: they get it through holes in the flower made by themselves or by previous visitors. Visitors in search of pollen may also contribute zilch to pollination if they eat pollen on the spot and take away few or no pollen grains. Sometimes they are too good at gathering it, carrying the entire loot back to their nests, leaving nothing for plant reproduction. In some cases, these pollination cheats can constitute the bulk of flower visitations. To complicate matters, visitors can be cheats and pollinators at the same time, or under different circumstances.

The sixteen-spot ladybird (Tytthaspis sedecimpunctata) is a keen flower visitor but an abysmal pollinator because it gobbles down pollen to its heart’s content © Gilles San Martin, Wikimedia Commons.

Pollination will happen only when pollen grains from the anthers (male parts of the plant) make their way to a stigma (female part). Evidence for this crucial event can be obtained by a sequence of conditions analogous to the Henle-Koch postulates. It must be demonstrated that pollen is transferred from anthers to the vector (the suspected pollinator), transported by the vector, and  deposited on a receptive stigma by the vector (Cox & Knox, 1988).

The process of cross-pollination © Ali Niaz, Wikimedia Commons.

These steps seem straightforward, but they are in fact not easy to prove. King et al. (2013) had a go at it with observations from two Scottish sites and a deciduous forest in Costa Rica. They kept an eye on recently opened flowers from 13 species, waiting for the first visitor to alight on a bloom. Once that happened, the stigma from that flower was taken to a laboratory, where pollen grains were recovered, identified and counted. By carrying out repeated observations, the authors obtained estimates of single-visit deposition (SVD), which measures a visitor’s ability to take pollen from a given plant and deposit it in another plant where it can lead to fertilization. By estimating SVD values of the main flower visitors, the authors discovered that about 40% of them were not effective pollinators.

In southeast England, bramble (Rubus fruticosus agg.) flowers are frequently visited during daytime by flies, bumble bees (Bombus spp.) and the European honey bee (Apis mellifera). But an analyses of SVD revealed that most pollination is done at night by moths (Anderson et al., 2023). In a similar vein, Ballantyne et al. (2015) evaluated potential pollinators of heather (Erica tetralix, E. cinerea and Calluna vulgaris) and gorse (Ulex europaeus and U. minor) in Hyde Heath, England. By combining the frequency of flower visitation with SVD values, it was possible to establish who was pollinating what. Hoverflies were frequent visitors, but they deposited few pollen grains. The European honey bee, another regular visitor, was an efficient pollinator of common heather (C. vulgaris), but not as good as bumble bees for the other plants. In fact, SVD data for 76 plants from 30 families in Kenya, Israel and UK have confirmed the frequently reported observation that the European honey bee, despite often being the most abundant flower visitor, is a less effective pollinator than are solitary bees and bumble bees (Willmer et al., 2017).

Networks illustrating a combination of frequency of flower visitation and mean SVD for the main pollinators of heather and gorse. 1: Bombus terrestris/lucorum; 2: B. pascuorum; 3: B. lapidarius; 4: B. jonellus; 5: B. hortorum; 6: A. mellifera; 7: Halictidae; 8: other solitary bees © Ballantyne et al., 2015.

If you suspect that estimating SVD is hard work, you are right. There are alternatives, such as percentage of flowers that develop into fruit, fruit weight, fruit production, and so on. But these methods are equally laborious and not as precise as SVD. A great number of studies have used visitors’ features such as their abundance, hairiness and size, their pollen load, the number of stigmas touched, and the frequency and duration of flower visits. These are indicators of visitors’ potential, but not proof of effectiveness. For example, pollen attached to a visitor’s body may be lost on the way, or end up on incompatible or unreceptive stigmas. We need evidence of pollen deposition that may lead to fertilisation.

A marmalade fly (Episyrphus balteatus) on a grey-haired rockrose (Cistus creticus) flower. Pollination in action? Possibly, but the presence of pollen grains alone does not guarantee it © Aka, Wikimedia Commons.

Conservation organisations, academics, the press and social media have reiterated—often exaggeratedly—the imperiled state of pollination services. These concerns heighten the importance of safeguarding pollinators’ abundance and welfare, and the quality and extent of their habitats. Pollinators are in the spotlight, which opens opportunities for public involvement, new projects, funding – and to bandwagon jumping. A range of flower visitors have been claimed to be pollinators based solely on the fact that they are flower visitors. Even a tree frog was recently reported in the press as a new member of the pollinators club because one specimen was observed with pollen attached to its back. Could it be a pollinator? Possibly, but not likely:  a frog or any animal may accidentally fertilise a flower, but that does not make them reliable, consistent pollinating vectors. Like any other scientific endeavour, progress in our understanding of pollination ecology and processes requires data resulting from hard work. Just listing creatures that fancy a pretty flower won’t do.

Flower-loving Pepé Le Pew is not likely to contribute to pollination © Prayitno, Wikimedia Commons.

Readers’ wildlife photos

May 4, 2024 • 8:15 am

Mark Sturtevant has answered the call for photos with some lovely pictures of insects and plants. Mark’s notes are indented, and you can enlarge the photos by clicking on them.

We begin with the tail end of a trip to Ohio last summer.

There is a terrific bog at a park there which I shall always visit when “bugging” in that state. I don’t often photograph flowers, but these Showy Lady’s Slipper Orchids Cypripedium reginae were abundant, and they are rather special since this species of Lady’s Slipper is generally rare. Visitors are not allowed to stray off of the boardwalks in the park, so my long lens came in handy here. That rule was frequently broken by others, btw, and it really ticked me off:

Next up is a new species of spider, the Western Lynx Spider (Oxyopes scalaris). Lynx spiders are ambush predators that sit up high on plants. Despite its common name, this species is widespread in the U.S., although it was new to me:

At a prairie location, these Soldier Beetles were abundant on various flowers where they were feeding on pollen. Their bright colors are a warning that they are not palatable. I thought they were two species, but it turns out they are both Margined Leatherwings, Chauliognathus marginatus, a species that comes in different color morphs:

Back we go to my resident state of Michigan. At a park some hours to the south of me, there were these mini-swarms of beetles that were feeding and mating on low shrubbery. Another new species. It turns out they are Clay-colored Leaf Beetles, Anomoea laticlavia, and they have an interesting biology in that their larvae live underground where they are tended by ants:

While on the subject of beetles having sex, here are a pair of Asian Ladybird Beetles (Harmonia axyridis), a species that has a number of other common names. They are an introduced and hugely dominant species of “ladybug”, and I worry that they have displaced some native species:

But now we get into some very special items. Near where I live is a park that has several wetland areas with “fens”, or at least that is what our park service calls them. I am told they also have features for “bogs”, however. The different types of wetlands are based on chemistry and water movement, plus the presence of various indicator plants.

Anyway, I call my favorite one “Sturtevant’s Fen” since its location is well off any trail and no one else goes to it. So it is a great place and it is all mine. One of its best features is that it harbors a healthy population of our smallest dragonfly, called the Elfin Skimmer (Nannothemis bella), is a species that is very fussy about the wetland conditions upon which it depends. Ever since I’ve known of these amazing little dragonflies, I’ve had a vision to photograph them in hand in order to convey how incredibly small they are. Catching them with a net was super easy. First, here is a male. I promise he is not being harmed. Next is the very different looking female. She had recently emerged, and so was not inclined to fly. This picture is one of my favoritest pictures I’ve ever taken! Elfin Skimmers are the 2nd smallest dragonfly in the world, and the smallest is a close relative found in China:

Sturtevant’s Fen also has orchids. The most common are these lovely grass pink orchids (Calopogon tuberosus). I believe this is a bog and not a fen indicator, but they are still very nice. The strange yellow thingies up top are lures that are meant to fool bees into foraging upon them since they look like anthers. The weight of the bee then causes the petal to tip down to the central column below, where sticky pollen sacs await to attach onto the hapless bee. Darwin would have appreciated the contrivances of these orchids: