Category: insects

Readers’ wildlife photos

March 11, 2026 • 8:30 am

Hooray! Two more groups of photos came in this morning and so we’re good through Friday (I have one in reserve and can cobble together a few others).

The regulars are pulling their weight, and here we have an informative text-and-photo educational post by regular Athayde Tonhasca Júnior. The subject is one of his favorites: bee behavior. You can enlarge Athayde’s photos by clicking on them, and his text is indented.

Witty impostors

On its release in 1956, Invasion of the Body Snatchers did not impress the critics. A spiel about alien plant spores growing into sociopathic duplicates of human beings was considered too outlandish. While the intelligentsia trashed the film, the producers laughed all the way to the bank because it was a commercial hit: the public loved it. One of the reasons for the film’s success was its ‘aliens among us’ theme. The idea of ill-intentioned beings circulating freely and unsuspectedly in the mist of our society is disturbing and gripping – especially during the McCarthy era, when Americans were inspecting their closets for hidden communists. ‘Enemies within’ inspired and inspires countless tales about spies, infiltrated assassins, covert extra-terrestrials, psycho cyborgs and zombified humans.

Fig 1. Invasion of the Body Snatchers received numerous accolades and is today considered a science-fiction/horror classic © Allied Artists, Wikimedia Commons:

Despite what assorted internet sages tell us, tales of aliens’ secret forays into world domination are entertaining fibs. But the natural world provides many real body snatching thrills such as parasitic flies that zombify their victims or induce them to dig their own graves, or wasps that make their hosts work for them. These cases involve species we may already suspect to be mischievous. That some bumble bees could play similar tricks may surprise many.

Superficially, cuckoo bumble bees, Bombus species of the subgenus Psithyrus, look like any of their social (non-parasitic) relatives. But a close inspection of a female’s hind leg shows no pollen basket (corbicula), which is a shallow cavity surrounded by a fringe of long hairs, a structure used to store pollen to be carried away.

Fig 2. Hind legs of a vestal cuckoo bumble bee (B. vestalis) on left, and a buff-tailed bumble bee (B. terrestris) © Alvesgaspar, Wikimedia Commons. [JAC: the buff-tailed bee has a pollen basket.]

She has no corbiculae because she gathers no pollen; cuckoo bumble bees do not found their own nests nor produce a worker caste: there are only male and female reproductive forms. Instead, a female invades the nest of a social bumble bee, lays her own eggs, which are cared for by her unsuspecting hosts. Raising the young at another species’ expenses is known as brood parasitism, a behaviour displayed by some cuckoo birds (order Cuculiformes) – hence Psithyrus bees’ common name.

Fig 3. A  common reed warbler (Acrocephalus scirpaceus) feeding a European cuckoo (Cuculus canorus) who has dispatched rival offspring by pushing them out of the nest © Per Harald Olsen, Wikimedia Commons:

Cuckoo bumble bees go beyond brood parasitism; they don’t just lay their eggs in a host’s nest and leave them to themselves like cuckoo birds do. These bees take over the victim’s colony, a form of exploitation known as social parasitism. Among insects, this strategy is employed mostly by bees, wasps and ants – of which slave-making ants are notorious – but also by other taxa such as the large blue butterfly (Phengaris arion). Once inside the host’s nest, the female cuckoo and her young live off pollen and nectar pilfered from their hosts, so they are also kleptoparasites – animals that steal food or prey from another animal.

We should pause to appreciate the challenges a cuckoo bumble bee faces. First, she has to locate the nest of a suitable host. She must then get in through a narrow entrance protected by a mob armed with poisonous stings and sharp mandibles. Once these defences have been overwhelmed, she must be able to usurp the colony from the host queen, lay her own eggs and induce the host workers to feed her and her developing brood. A tall order for any brood, social and klepto- parasite.

Fig 4. Cuckoo bumble bees coveting this tree bumble bee (B. hypnorum) nest must pass its sentries © Orangeaurochs, Wikimedia Commons:

Finding a nest is reasonably straightforward: like most social insects, cuckoo bumble bees rely on chemical signals from cuticular hydrocarbons to recognise nestmates, co-specific competitors and potential hosts. But locating a nest is just the start. It must be of suitable size: if too big, the defenders are likely to overwhelm and kill the trespasser; if too small, there will not be enough workers to care for her larvae. As an example, there’s a 100% survival for vestal cuckoo bumble bees invading buff-tailed bumble bee nests with five workers; survival drops to nil for colonies with fifty workers (Sramkova & Ayasse, 2009). To avoid disaster, the female cuckoo bumble bee assesses the size of the host colony possibly by their chemical signals and workers’ traffic (Lhomme & Hines, 2018).

After picking an appropriate target, the female cuckoo bumble bee must confront the residents, who understandably are not obliging. But the nest defenders face a formidable enemy: a cuckoo bumble bee is sturdier and better armed than her social counterparts. She has larger and stronger mandibles, more powerful sting muscles, an enlarged venom gland, and her ventral underside, a particularly vulnerable spot, is protected by thicker exoskeleton plates (sternites) (Richards, 1928). So, some cuckoo species use brute force: they bite, push and sting their way in.

Fig 5. Armed for breaking and entering: the variable cuckoo bumble bee (B. variabilis), a critically endangered North American species © USGS Bee Inventory and Monitoring Lab:

But violence is not always necessary. Some species are let in because they mimic their host’s chemical signs. Others have no chemical signatures and display no aggressive behaviours; the host bees are not aware an enemy has sneaked in. The cuckoo will hide in a corner of the nest for a few days, long enough to acquire the scents of her host and blend in (Dronnet et al., 2005).

Once inside, our intruder has to deal with the queen, the only egg-laying member of the colony and thus the mother of all other bees, whose activities are controlled by their mum’s pheromones. Most cuckoo bumble bees don’t beat about the bush; they kill the queen and eat her eggs. Some species spare the deposed monarch, who loses control of her colony for reasons not completely understood: probably the usurper’s pheromones and physical aggression assure her dominance over the queen.

Fig 6. A brown-belted bumble bee queen (B. griseocollis) is strong, but no match for a cuckoo bumble bee © USGS Bee Inventory and Monitoring Lab:

After sorting out the queen problem, the cuckoo bumble bee is free to lay her own eggs and induce the host workers to feed her and her developing young, although how this is done is largely unknown. The resulting male and female cuckoo bees will leave the nest by late summer and look for mating partners. Like most other bees, the male dies soon after intercourse, while the female will search for a safe spot underground to overwinter, just like her hosts. She will emerge from her slumber late, giving sufficient time for her hosts to establish their nests. The female cuckoo bee spends some time hopping from flower to flower, sipping nectar while her ovaries mature, so that she will be ready to find and conquer a bumble bee nest.

Of the 250 or so Bombus species, roughly 30 have evolved into parasitism. We have a poor grasp of cuckoo species’ biology and ecology, partly because they fly about for a relatively short time and their numbers are naturally low, since they don’t have a worker caste. Thus they are difficult to find and study. But the lack of information comes largely from prejudice. Parasites in general are not viewed sympathetically, especially those that target ‘cute and lovable’ victims such as bumble bees. As a result, cuckoo bumble bees are often absent from local species lists and conservation plans. But that’s a misguided view. Parasites and predators are integral components of ecosystems, preventing over-dominance of some species in favour of rarer ones (Frainer et al., 2018). Cuckoo species should be admired and valued for their physiological, morphological and behavioural adaptations that allow them to overcome the defences of highly organised colonies. These bees of ill-repute are in fact evolutionary marvels.

Fig 7. A female red-tailed cuckoo bumble bee (B. rupestris), a widespread European species and a parasite of the equally abundant red-tailed bumble bee (B. lapidarius) © Ivar Leidus, Wikimedia Commons:

References

Dronnet, S. et al. 2005. Bumblebee inquilinism in Bombus (Fernaldaepsithyrus) sylvestris (Hymenoptera, Apidae): behavioural and chemical analyses of host-parasite interactions. Apidologie 36: 59–70.

Frainer, A. et al. 2018. Parasitism and the biodiversity-functioning relationship. Trends in Ecology and Evolution 33: 260–268.

Lhomme, P. & Hines, H. 2018. Ecology and evolution of cuckoo bumble bees. Annals of the Entomological Society of America 112: 122–140.

Richards, O.W. 1928. A revision of the European bees allied to Psithyrus quadricolor Lepeletier (Hymenoptera, Bombidae). Transactions of the Entomological Society of London 76: 345–365.

Sramkova, A. & Ayasse, M. 2009. Chemical ecology involved in invasion success of the cuckoo bumblebee Psithyrus vestalis and in survival of workers of its host Bombus terrestris. Chemoecology 19: 55–62.

Readers’ wildlife photos

February 25, 2026 • 8:20 am

Plant lovers and botanists will be especially pleased by today’s selection of lovely photos from Thomas Webber. Thomas’s captions and IDs are indented, and you can enlarge the photos by clicking on them (recommended).

The theme for today’s installment is Gone to Seed. Here are a few north-Florida flowers shown in their prime and afterward, when their glamor parts had been replaced by seed enclosures, bare seeds, or merely the dried remains of the flower bases. All of them grew within Gainesville’s city limits, at sites from semi-pruned to semi-wild. I think I’ve identified them all correctly to species this time, but I invite corrections.

Frostweed, Verbesina virginica. Individual flowers 1 cm. Native:

These bracts, called phyllaries, surround the bases of the flowers. In late February a few of their papery remnants are still aloft on their brittle four-foot stalks:

Low rattlebox, Crotalaria pumila. 2.5 cm across. Native. The map in the article linked here is incomplete and does not reflect the herbarium records for Alachua County, where I took this picture.

Showy rattlebox. C. spectabilis. 3.5 cm across. Native to southern and southeast Asia, now widely naturalized in southeastern North America:

C. spectabilis seed pods. 4 cm long. The pods of C. pumila look similar but are smaller. Crotalaria, and especially their seeds, are laden with toxic alkaloids. Larvae of the rattlebox moth, Utetheisa ornatrix, bore through the walls of the pods and feed on the seeds. Somehow the caterpillars manage to detoxify the alkaloids enough so they aren’t poisoned, while remaining poisonous enough to deter most animals that might try to eat them. The larvae retain the toxins into the flying-moth stage, and at both stages their distinctive vivid color pattern warns predators to leave them alone.

A rattlebox-moth caterpillar. About 3 cm. I doubt that I could have found any of these if I’d gone looking for them, but this one crawled right in front of me while I tried to get a picture of the low rattlebox. It held fairly steady for a few seconds, letting me capture enough detail to identify it. I didn’t have my choice of background:

Tropical sage, Salvia coccinea. 3 cm. Native. At this latitude these remain at their peak through late December:

All that’s left in late February are these cones called calyces, which are fused sepals:

Spanish needles, Bidens alba. 2.5 cm. Native. This is the king weed of these parts, growing everywhere and sometimes in great masses; one dense bunch covers an acre of a low damp lot in the middle of Gainesville:

Seeds of Spanish needles. 1 cm long. The name of the genus, meaning two-teeth, derives from the forks at the tips of the seeds. The barbs on these projections are part of an impressive example of convergent biological and cultural evolution, and have turned out to be just the thing for attaching the seeds to socks and shoelaces:

Dotted horsemint, Monarda punctata. Whole flower head 2.5 cm wide. Native. The most complicated flowers I find around here:

All of that elaborate presentation goes to produce seeds 1 mm in diameter, too small to show well with my basic macro gear. At this stage you can still shake a few of them from the calyces. Thanks to Mark Frank of the Florida Museum of Natural History herbarium for a remedial lesson in the difference between calyces and phyllaries:

Beggarweed, Desmodium incanum. 1 cm across. Native to Central- and South America, naturalized in the southeastern U.S. This year, by means unknown, a few of them showed up for the first time in what passes for my lawn:

Beggarweed pea-pods, 3 cm long:

Scarlet morning glory, Ipomoea hederifolia. 4 cm long. Native:

Morning-glory seed pods, 7 mm. The hard little capsules cleave along their sutures and split open to release black seeds the shape of orange sections, exposing the translucent porcelain-like septa that divided them:

Readers’ wildlife photos: Darwin Day edition

February 12, 2026 • 8:15 am

Today we have a Darwin-themed text-and-photo contribution by Athayde Tonhasca Júnior, and on his favorite topic: pollination (and my favorite topic, speciation). Athayde’s IDs and narrative are indented, and you can enlarge his photos by clicking on them.

Parting ways

As superlatives go, it would be difficult to beat the South African Platland Baobab [Adansonia digitata]. Its 10.6-m diameter trunk was large enough to accommodate a bar inside its hollow trunk. The massive tree, now deceased, was also old – it had been on this Earth for about a millennia.

There aren’t many places where you can order a pint inside a tree like the Platland or Sunland Baobab © South African Tourism, Wikimedia Commons:

Leaving aside its connection to thirsty pilgrims, the Platland Baobab was not exceptional: other specimens belonging to the same African baobab (Adansonia digitata) species are similarly big and old. The African baobab’s size, age and the somewhat bizarre shape (the ‘upside-down tree’) inspired many legends and superstitions. Beyond the mythical, baobabs have practical uses to some rural communities in parts of Africa: fruits and leaves are rich in vitamin C, the bark can be used for making rope, and tree hollows serve as water reservoirs. Wildlife also feed on baobab’s parts, sometimes in excess: elephants eat baobab bark during the dry season, resulting in significant tree mortality when elephant numbers are high.

One African titan squaring up to another © Ferdinand Reus, Wikimedia Commons:

Like the vast majority of flowering plants, the African baobab is a hermaphrodite:  its flowers have male and female reproductive organs. And like most hermaphrodite plants, baobab flowers are self-incompatible; they can’t fertilise themselves. Therefore, pollinators have to come to their reproductive aid. That’s particularly important for African baobabs, which often grow in isolation, with an average of 2 trees/ha.

When researchers started investigating baobab reproduction in West and East Africa in the 1930s and 40s, bats were soon singled out as their likely pollinating agents. It made sense: the white, large (up to 200 mm in diameter) pendulous flowers open at night and release a musty smell, all signs of chiropterophily, or pollination by bats. But things are a bit more complex. Flowers in west and east Africa are mostly visited by the straw-coloured fruit bat Eidolon helvum (Eidolon helvum) and the smaller Egyptian fruit bat (Rousettus aegyptiacus), respectively. However in southern Africa, baobab flowers have no appeal to bats, but do attract hawk-moths. These regional differences are linked to floral features such as shape, scent and nectar volume. In west Africa, flowers are larger, have longer peduncles, longer styles and more nectar than flowers in east and southern Africa. East African flowers are smaller and sturdier, with less nectar but enough to encourage visits by the Egyptian fruit bat. Flowers in southern Africa are smaller still and produce nectar in volumes just enough for moths (Venter et al., 2025).  And while baobabs flowers from the three regions release bat-attracting sulphur compounds, southern African flowers also produce β-caryophyllene, a chemical known to lure moths (Karimi et al., 2021).

Below:  A) A straw-coloured fruit bat in west Africa feeding on a baobab flower while a hawk-moth thieves, that is, it takes nectar but does not pollinate. B): an Egyptian fruit bat in east Africa landing briefly to lick nectar. C:) a long-tongued and a short-tongued hawk-moths feeding in southern Africa © Venter et al., 2025:

The African baobab is by no means unique; many other species comprise populations of diversified floral traits that suit particular pollinators and local environmental conditions. Ecologists refer to each of these populations as pollination ecotypes, species complexes, geographical races or ecological races. Pollination ecotypes have one possible outcome of exceptional importance: given enough time, they may drift further apart in their morphological and physiological traits to the point of becoming reproductively incompatible with each other.

Examples of pollination ecotypes. Long-spurred Platanthera bifolia pollinated by the hawk-moth Sphinx ligustri (a) and a shorter-spurred form pollinated by the hawk-moth Hyloicus pinastri (b); short-tubed Gladiolus longicollis pollinated by hawk-moths with short probosces (c) and a long-tubed form pollinated by hawk-moths with long probosces (d). © Johnson, 2025:

It’s worth emphasising the meaning of such an outcome. Different forms – or morphs – in each ecotype associated with their own pollinators will eventually become different species, a process that has become widely acknowledged (Johnson, 2025). Speciation via ecotypes supports Darwin’s view that species and infraspecies taxa (varieties, subspecies, forms, morphs, etc.) represent a continuum: In short, we shall have to treat species in the same manner as those naturalists treat genera, who admit that genera are merely artificial combinations made for convenience. This may not be a cheering prospect; but we shall at least be freed from the vain search for the undiscovered and undiscoverable essence of the term species (Darwin, 1859). Such a continuum implies that speciation is much more common and frequent than one may expect (Mallet, 2008).

The roles of insect pollinators as safeguards of biodiversity, crop production and human health are well known and celebrated. But the tale of African baobab pollination ecotypes reminds us of another fundamental aspect: pollinators greatly contribute to the radiation and diversification of angiosperms, the largest and most diverse group in the plant kingdom and largely responsible for the functioning of all terrestrial ecosystems. It’s a hefty responsibility upon tiny shoulders.

Accumulated diversification of insect families through time. Dotted lines indicate the Permian–Triassic (P–T), Triassic–Jurassic (T–J), and the Cretaceous–Paleogene (K–Pg) mass extinctions © Peris & Condamine, 2024:

References

Darwin, C.R. 1859. On the Origin of Species by Means of Natural Selection. John Murray.
Johnson, S.D. 2025. Pollination ecotypes and the origin of plant species. Proceedings of the Royal Society B 292: 20242787.
Karimi, N. et al. 2021. Evidence for hawkmoth pollination in the chiropterophilous African baobab (Adansonia digitata). Biotropica 54: 10.1111/btp.13033.
Mallet, J. 2008. Hybridization, ecological races and the nature of species: Empirical evidence for the ease of speciation. Philosophical Transactions of the Royal Society of London B 363: 2971-2986.
Peris, D. & Condamine, F.L. 2024. The angiosperm radiation played a dual role in the diversification of insects and insect pollinators. Nature Communications 15: 552.
Venter, S.M. et al. 2025. Regional flower visitor assemblages and divergence of floral traits of the baobab Adansonia digitata (Malvaceae) across Africa. Botanical Journal of the Linnean Society boaf085.

Readers’ wildlife photos

February 10, 2026 • 8:15 am

Today we have some urban arthropod photos taken in Scotland by Marcel van Oijen. Marcel’s IDs and captions are indented, and you can enlarge his photos by clicking on them.

Urban wildlife in Scotland: 11 insects and 1 spider

Marcel van Oijen

This website recently hosted pictures of vertebrates in our Edinburgh garden. This time we show some of our favourite arthropod visitors. Unlike the vertebrates, which we see year-round, insects in Scotland are easiest to spot in the summer, followed by spiders in autumn. The following pictures were taken between mid-July and mid-September.

When we walk on the grass in summer, we see small bits of straw rising up and landing a meter or so away. Those are Straw Grass Moths (Agriphila straminella), one of the 2500 moth species in the UK. Grass moths are micromoths of about 1 cm length. When they land on the grass, they immediately freeze and allow themselves to be photographed from up close:

Once or twice a year we put out the moth trap to see what lives in our garden. The trap is just an open box with a lamp above. The moths fly toward the light and hide in the box, allowing us to admire them the next morning. Mornings are relatively cold, so most boxed moths hesitate to fly away even when we carefully take them out and take pictures. It is still not fully clear why moths are drawn to artificial light, but flight analysis suggests they treat lamps and natural light sources in the same way . We see Orange Swift Moths (Triodia sylvina) quite often. They are doing well, populations are increasing and expanding further into Scotland, but they are yet to reach Ireland.

Scalloped Oak Moth is another common species (Crocallis elinguaria):

There are 57 species of butterfly in the U.K. of which 35 breed in Scotland. We see Comma butterflies (Polygonia c-album) more and more each year:

There are two insects in this picture! Notice the huge size difference between the Buff-Tailed Bumblebee (Bombus terrestris) and the Highland Midge (Culicoides impunctatus). The cute little midge is the reason why we don’t go wild camping in the Scottish Highlands in the summer, but in Edinburgh they are still fairly rare:

This is the most common hoverfly species in the U.K. (Helophilus pendulus):

The Peacock (Aglais io) is found all across Eurasia, and we see it very often. It is beautiful (but we like the moths more):

Like many larger butterflies, the Red Admiral (Vanessa atalanta) lets itself easily be photographed if you slowly move toward it, staying as low as you can:

The macromoth species that we see the most is the Large Yellow Underwing (Noctua pronuba). You can see that this one is nearing the end of its lifetime:

I find it difficult to take pictures of flies, so was happy to see this Common Siphona Fly (Siphona geniculata) land on the flower that I had just focused on:

The Eyed Ladybird (‘Ladybug’ in American) (Anatis ocellata) is one of the prettiest aphid-eaters:

And this is the only spider for today: a subadult of the Lesser Garden Spider (Metellina segmentata). Seeing it is a sign that autumn has come:

Readers’ wildlife photos

February 2, 2026 • 8:15 am

Well, this is the last batch of submitted photos, but I hope for me. Don’t dash my hope!

Today we have a lovely text-and-photo post by Athayde Tonhasca Júnior, featuring a bizarre and mimetic beetle. Athayde’s captions are indented, and you can enlarge the photos by clicking on them.

Fabulous pretenders

Termites, cockroaches’ sophisticated cousins (Order Blattodea), live in intricate, organized societies with division of labour and a caste system. The mound-building species are also skilled engineers, constructing temperature-controlled, ventilated nests that protect their inhabitants from the harsh conditions of the outside world.  Colonies may comprise millions of individuals, including eggs, larvae and workers. Just like other social insects, termites have to be on guard against many an envious enemy: their cosy nests are tempting to would-be squatters, with the even more tempting bonus of being packed with energy-rich morsels.

Termite workers and soldiers ready to defend a damaged sector of their nest © U.S. Department of Agriculture, Wikimedia Commons:

Damage to a nest of Formosan subterranean termites brings hoards of workers and soldiers with dark, oval shaped heads scrambling to repair the hole. Termites shown about 4 times actual size. USDA photo by Scott Bauer.

Termites are mostly successful in keeping invaders at bay, but a sizable group of outsiders has evolved skills that allow them to breach those defences. These are the termitophiles: macro-organisms that live in association with termite colonies. Termitophiles, ranging from harmless inquilines to predators and parasites, rely on chemical mimicry and numerous morphological and behavioural adaptations to avoid detection and mingle with their hosts.

Among the many impostors, rove beetles from the subfamily Aleocharinae are particularly noteworthy. This is a huge group (~16,000 species) within the humongous Staphylinidae family, which comprises some 66,000 species, one of the largest families of organisms. Many aleocharines are myrmecophilous (associated with ants); some 670 species are termitophilous.

The termitophilous rove beetle Corotoca phylo © Zilberman et al., 2019:

Aleocharines have reached extraordinary levels of deception, but two termitophilous species of the genus Austrospirachtha from northern Australia – the only known species so far –  take their art to a new level. On first seeing their images, one may think they are AI-generated. Or pranks devised by putting together bits of different insects, entomological versions of the Piltdown Man hoax.

A. carrijoi, lateral and dorsal views. Its recent discovery caused a sensation © Pires Silva, 2024:

The first described species, the less publicised A. mimetes. Lateral view, setae omitted (1) and abdomen viewed from above (2) © Watson, 1973:

The termite puppets on their backs, complete with dangling pseudo-appendages that resemble antennae and legs, fool their hosts into accepting them as nestmates. You may see these beetles as rough simulacrums of the real thing, but in the pitch-dark confines of a termite nest, mimicry is based on palpation rather than vision (Watson, 1973).  The mouthparts of A. carrijoi are very small, which suggest it dupes termite workers to feed it, a process known as trophallaxis (Zilberman & Pires Silva, 2023). Presumably, the same happens with A. mimetes.

We know very little about these beetles or any other symbiotic aleocharines. But the rare insights into their outlandish appearances are glimpses of the marvellous workings of natural selection.

References

Pires Silva, C.M. 2024. Cladistic analysis, taxonomic revision & biological notes of the termitophilous genus Xenogaster Wasmann, 1891 (Staphylinidae, Aleocharinae, Corotocini). Master’s Dissertation, Universidade de São Paulo, Brazil.

Watson, J.A.L. 1973. Austrospirachtha mimetes, a new termitophilous corotocine from Northern Australia (Coleoptera: Staphylinidae). Journal of the Australian Entomological Society 12: 307-310.

Zilberman, B. et al. 2019. Viviparity in Staphylinidae and reproductive behavior of Corotoca Schiødte, 1853. Papéis Avulsos de Zoologia 59: e20195919.

Zilberman, B. & Pires Silva, C.M. 2023. A new species and morphological notes on the remarkable termitophilous genus Austrospirachtha Watson from Australia (Coleoptera: Staphylinidae: Aleocharinae). Zootaxa. 5336: 424-432.

Readers’ wildlife photos

January 20, 2026 • 8:15 am

Regular Mark Sturtevant (as opposed to Irregular Mark Sturtevant) has sent in some lovely insect photos to fill the nearly-empty reserve of pictures. Please send any good wildlife photos you have. Thanks!

Mark’s captions are indented, and you can enlarge his photos by clicking on them. Be sure to check out the female Tussock Moth caterpillar with vestigial wings (it’s the eighth photo).

Here is another dispatch of local insects and spiders, all photographed either in area parks near where I live in eastern Michigan, or as staged shots at home. Let’s start with a couple of dragonflies. First up is a Green Darner (Anax junius), which ranks pretty large among the dragonflies found here. As is almost always the case, this individual is a female, since they perch frequently and are much easier to approach than males, which I only rarely manage to photograph. Do you see the tiny yellow critter on the dragonfly? That is a Globular Springtail, and it must have walked or jumped onto the dragonfly from nearby foliage. There may be a few more of them in the picture as well, though I’m not certain. Springtails are tiny soil arthropods, and they are extremely abundant. When seen up close, Globular Springtails are arguably adorable, as you can see in the linked image. I’ve searched for them for some time but have only rarely encountered them, despite claims that they are exceedingly common. Perhaps our local species spends more time up on foliage rather than in the soil, meaning I’ve been looking in the wrong places!:

The next dragonfly is a male Skillet Clubtail (Gomphurus ventricosus), named for the large, pan-like club on the end of its abdomen. I have to drive a few hours south to a particular park to see them, and of course this one is perching on poison ivy which covers much of the area there. That park hosts 8 or 9 species of clubtails according to a dragonfly documentation site called Odonata Central. I’ve photographed most of those species with only two left to find:

A field near my workplace has a ridiculously high population of Chinese Praying Mantids (Tenodera sinensis). I suspect this is the lingering result of someone having released a large number of egg cases several years ago, combined with a robust population of grasshopper prey. Shown here is a young June nymph. I can return later in the summer to find several large adults in no time at all:

Next up are some lepidopterans. First is a Hackberry Emperor butterfly (Asterocampa celtis). They are often common along forest margins where their host Hackberry trees [Celtis occidentalis] are concentrated. Their caterpillars, however, seem to be quite secretive, as I’ve seen only a few of them:

Next is an inchworm caterpillar, though I don’t have an identification for it. Do you see the tiny mites?:

The insect shown next is a moth, although it makes a very convincing wasp mimic. This is the Eupatorium Borer Moth (Carmenta bassiformis). The larvae feed on the roots of Ironweed and Joe Pye Weed, both of which are highly valued native wildflowers because they are very much favored by butterflies:

The flamboyant caterpillar in the next image is a White-marked Tussock Caterpillar (Orgyia leucostigma). I’ve tried several times to get an acceptable focus-stacked image of one of these. What makes them difficult is the combination of all those oddly angled sticky-out bits, which challenge the shallow depth of field inherent in this kind of photography, along with the fact that these caterpillars absolutely will Not Hold Still. As a result, the stacking is done on the fly, followed later by long hours of manual reassembly of the jumbled focus stack. This image is by far my most successful attempt:

I kept this caterpillar in hopes that the moth emerging from the cocoon would be a female. Why? Well—check out what came out! It was a female! Females have barely visible vestigial wings, and I had never seen one before. She will sit here, unmoving, until a male finds her. This strategy saves a great deal of energy that can instead be used for laying eggs. The winged males are unremarkable, and while I’ve probably seen them, I don’t think I’ve ever photographed one:

Finally, here are three images of jumping spiders I’ve been wanting to share together for quite some time. The Dimorphic Jumping Spider (Maevia inclemens) is a species I regularly see around the outside of our house. The name refers to the males having two distinct color morphs. The images below are manual focus stacks, photographed in staged settings on the ‘ol dining room table. First is a female with long-legged fly prey, which conveniently provides a sense of scale since the fly is about the size of a mosquito:

Next are the two male color morphs. The first somewhat resembles the females, while the other is very different and comes with distinctive hair decorations. This is an older image, but I’m bringing it back so all three forms can finally be shown together. It’s surprising that they are all the same species!

I recently learned that the two male forms use different courtship displays for females, yet are considered equally successful in the mating game. I’m sure Jerry can steer things in the right direction if I am in error here, but having different male forms with different mating strategies does not seem unusual in the animal kingdom. Examples I’m familiar with include lizards, crustaceans, and fish, although in those cases the different males include those that are aggressive and territorial, and others that win by being sneaky. But here, I don’t see how either male is territorial, and apparently both have courtship displays for females.

One of my goals for next season will be to try to document their different courtship behaviors. That seems do-able, since I can expect to find several of them again next summer.

Readers’ wildlife photos

January 19, 2026 • 8:15 am

Today we have a photo-and-text submission from Athayde Tonhasca Júnior on fly migration. It’s a subject dear to my heart as I used to work on it, publishing three papers on migration in Drosophila.  Athayde’s subject, though, is hoverflies, not fruit flies. His captions are indented, and you can enlarge his photos by clicking on them. Note: I changed Athayde’s words “hover flies” to the more common usage “hoverflies,” but Athayde notes that most entomologists use the two-word rather than one-word description.

On the road again, goin’ places that I’ve never been

Sometime between 1400 and 1200 BC, Yahweh (aka God) decided it was time to nudge the Egyptians to let their captive Israelites go. Yahweh could have tried diplomacy, but in his infinite wisdom he concluded that “The Egyptians shall know that I am the LORD”. And there was no better way to let the Pharaoh and his people know who the bigwig was around there than by punishing them with a series of plagues. Of the ten celestial disasters inflicted upon the Egyptians, two involved mosquitoes (or midges) and flies, which probably were also the agents behind another two plagues manifested as infectious diseases of people and livestock. Yahweh understood very well the efficacy of some flies (order Diptera) and pathogens to wreck revenge – after all, he created them.

Fig 1. The Third Plague of Egypt, by William de Brailes, circa 1250. Aaron strikes his rod on the ground, transforming dust into gnats (kinnim in Hebrew). In the King James version of the Bible, lice are the culprits, but today most scholars accept that kinnim should be translated as ‘gnats’ or ‘mosquitoes’ © Jan Luyken, 1712, Wikimedia Commons:

The tales of pestilent flies depicted in the book of Exodus could have been inspired by real events, as pest infestations and epidemics were recurrent in the ancient world. Fly outbreaks are facilitated by these insects’ capability to disperse for long distances and arrive at new locations suddenly and in massive numbers. There are no better examples of these efficient colonisers than hoverflies or syrphid flies (family Syrphidae) such as the marmalade (Episyrphus balteatus) and the migrant (Eupeodes corollae) hoverflies. Each autumn, they leave Britain and head south to spend the winter in southern Europe and the Mediterranean. Their offspring move northwards in the spring, lay eggs, and the new generation sets out on the cycle again. Researchers have estimated that up to four billion marmalade and migrant hoverflies cross the English Channel to and from Great Britain every year. This represents 80 tons of biomass. If you are impressed by these figures, you should know that hoverflies account for a fraction of insects’ latitudinal migrations known as ‘bioflows’: about 3.5 trillion insects, or 3200 tons of biomass, migrate into southern Britain annually (Wotton et al., 2019). Insect bioflows pour vast amounts of nutrients (particularly nitrogen and phosphorus) and countless prey, predators, parasites and herbivores into ecosystems, but we have only a vague understanding of their impact on food webs and local species.

Fig 2. A female marmalade hoverfly, a long distance frequent flier © Guido Gerding, Wikimedia Commons:

These hardy wanderers have another particularity of significant ecological importance: they transport pollen grains.

Most flies have no pollen-collecting structures and have few ‘hairs’ (setae), which are important pollen gatherers. These are negative marks for candidates to the pollinators’ club, but some flies compensate their shortcomings by their massive numbers. Each marmalade and migrant hoverfly carries an average of 10 pollen grains from up to three plant species on their journey into Britain. That’s paltry compared to a bee, but altogether, those flies bring in 3 to 8 billion pollen grains on each inward journey.

Pollen importation via flies is a recurrent phenomenon. In Cyprus, warm temperatures and favourable winds bring millions of insect migrants from the Middle East region, more than 100 km to the east. Flies make up nearly 90% of these bioflows, and many of them are loaded with pollen (Hawkes et al., 2022).

Fig 3. A common drone fly (Eristalis tenax) (A) and a blowfly (Calliphora sp.) (B) with orchid pollinia attached to their heads after a > 100-km sea crossing to Cyprus © Hawkes et al., 2022:

Pollen-loaded flies can turn up anywhere the wind takes them, even to specks of dry ground in the middle of nowhere. Over a two-month period, 121 marmaladehover flies reached a North Sea oil rig approximately 200 km from Aberdeen, UK. Over 90% of these flies had pollen attached to them, sometimes from eight plant species. Based on pollen barcoding and wind trajectory modelling, it was estimated that these flies traversed from 265 to 500 km of open water in a single journey, probably from the Netherlands, Germany and Denmark (Doyle et al., 2025).

Fig 4. (a) Location of an oil rig visited by hoverflies (b), and its aerial view © Doyle et al., 2025:

Flies’ long-distance pollen transfers may help connect isolated plant populations, such as in fragmented habitats, but we don’t know much about the ecological implications. However we do know that their contribution can be important. In continental Europe, wild carrot (Daucus carota) depends on a range of insects for pollinators, especially bees. But bees are absent from La Foradada, a 1,6 ha Mediterranean islet about 50 km off the Spanish coast. In this solitary spot of land, D. carota subsp. commutatus relies on the accidental arrival of common drone flies for its pollination (Pérez-Bañón et al., 2007).

Fi 5. La Foradada, devoid of bees and humans, is visited by pollinating drone flies © JavierValencia2005  Wikimedia Commons:

Butterflies, bumble bees, moths and dragonflies are known travellers, but we know much less about migrant flies, which may have significant roles in pollination ecology. We just have to pay more attention to these unpretentious pilgrims.

References

Doyle, T.D. et al. 2025. Long-range pollen transport across the North Sea: Insights from migratory hoverflies landing on a remote oil rig. Journal of Animal Ecology 94: 2267–2281.
Hawkes, W.S.L. et al. 2022. Huge spring migrations of insects from the Middle East to Europe: quantifying the migratory assemblage and ecosystem services. Ecography e06288.
Pérez-Bañón, C. et al., 2007. Pollination in small islands by occasional visitors: The case of Daucus carota subsp. commutatus (Apiaceae) in the Columbretes archipelago, Spain. Plant Ecology 192: 133-151.
Wotton, K.R. et al. 2019. Mass seasonal migrations of hoverflies provide extensive pollination and crop protection services. Current Biology 29: 2167–2173.