Category: insects

Readers’ wildlife photos

April 27, 2026 • 8:15 am

Today we have photos of stick-mimicking insects from Trinidad and Tobago, all taken by Ephraim Heller. Ephraim’s captions and IDs are indented, and you can enlarge the photos by clicking on them.

I remember the fascination I felt as a child on the rare occasions when I was taken to a zoo that had a terrarium containing stick insects. I still feel that way. In researching this post, I discovered that stick insects are even more remarkable and unusual than I anticipated. For example, parthenogenesis is common; they regrow lost limbs; and the world’s longest insect is Phryganistria chinensis, found in China and measuring 36 cm in body length (62 cm or 2 feet with legs extended, photo here).

I photographed two species. The first four photos are the Trinidad log insect (Phanocles keratosqueleton), known in regional folklore as the “god horse” or “hag’s horse.” It appears in folklore as an omen of death, despite being a harmless herbivore.

I never found a stick insect during our daytime hikes. During daytime, stick insects press themselves flat against plants and remain motionless, rendering them camouflaged and invisible. After dark, they walk out onto exposed vegetation to feed, molt, and mate. They are easily spotted with a headlamp due to their eyeshine:

Their camouflage can incorporate three distinct adaptations: cryptic coloration and background matching; cryptic body shape and texture; and behavioral crypsis (swaying when disturbed, mimicking a twig moving in a breeze). Not only are the insects themselves camouflaged, but many species evolved eggs that look like plant seeds:

Stick insects are in the order Phasmatodea, which contains over 3,500 species. Phasmids sits under Polyneoptera, which contains other winged insects such as grasshoppers, mantises, stoneflies, and earwigs. They are found on all continents except Antarctica. Against my expectations, Phasmatodea is monophyletic: the group evolved once from a single common ancestor, rather than through convergent evolution:

The next six photos are of the Trinidad twig or Trinidad stick (Ocnophiloidea regularis). More details on this species are at the end:

The oldest phasmid fossil is about 165 million years old, but recent studies claim that Phasmatodea first evolved 252 – 299 million years ago. This suggests that they evolved in response to the radiation of early insectivorous vertebrates such as parareptiles, amphibians, and synapsids. A major diversification occurred in the late Cretaceous, with the rapid spread of flowering plants (providing new foliage types to mimic) and the emergence of early birds:

Stick insect species’ reproduction ranges from sexual to obligate parthenogenesis, and much in between. Parthenogenesis (reproduction without fertilization) is common and has evolved independently many times among phasmids. Parthenogenic offspring are almost always females, producing all-female or near-all-female lineages. The offspring are not true clones of the parent, but are typically homozygous and have reduced genetic diversity, which can impair their ability to adapt to new stresses. Some species are facultatively parthenogenetic, meaning females can switch between sexual and asexual reproduction depending on conditions:

Phasmids can voluntarily shed a leg when grabbed by a predator. The leg is broken off at a specialized weak joint. Phasmatodea is the only insect order known to regenerate lost legs. Regeneration is restricted to nymphs because it requires molting. Cells at the wound site dedifferentiate and form a mass called a blastema, which then rebuilds the limb segment by segment through successive molts. The same molecular signaling pathway (ERK/CK2) involved in vertebrate limb regeneration drives the process in stick insects, which has attracted research interest for regenerative medicine. Regeneration is not free. Regrowing a leg during development results in disproportionately smaller wings and measurably reduced flight performance in adults. The body appears to divert resources away from wing development to fund limb repair:

The Trinidad twig (photos above and below) reproduces sexually:

The photo below shows two males attached to a female. Phasmids don’t do polycules and this is not standard reproductive behavior, but research on a closely related species has documented this scenario. While one male is guarding a female by remaining clasped to her abdomen, a rival male can approach and attempt to insert his genitalia while the first mate is momentarily repositioning or feeding. If the rival succeeds in attaching, both males end up simultaneously clasped to the female. This can result in a slow-motion “boxing-like” confrontation, with both males leaning backward and suspended from the female while trading blows with their forelegs until one of the males is eventually displaced:

Readers’ wildlife photos

April 6, 2026 • 8:15 am

Today’s photo come from reader Jan Malik, who took them in New Jersay. Jan’s captions are indented, and you can enlarge the photos by clicking on them.

As an appendix to the earlier Tree Swallow pictures, here are a few more from the New Jersey Botanical Garden. A walk in that park on the first day of spring is a ritual of mine—to ensure all observable phenomena related to spring are happening again and that the thermal death of the Universe is postponed for yet another year.

Red-bellied Woodpecker (Melanerpes carolinus) pausing mid-search for food. This is a female; in this species, the red plumage is restricted to the nape and the area above the bill, whereas males sport a continuous red cap:

Spring Snowflake (Leucojum vernum, possibly var. carpathicum), a Eurasian transplant. It looks succulent, but this perennial defends itself against mammalian browsing by producing bitter, poisonous alkaloids:

Eastern Cottontail (Sylvilagus floridanus) hiding in bearberry brambles. Against this notorious garden destroyer, only the Holy Hand Grenade of Antioch offers a true degree of protection:

Forsythia (Genus Forsythia) in bloom—the unmistakable sign that spring has arrived:

White-breasted Nuthatch (Sitta carolinensis). Like the woodpecker, it is a connoisseur of arthropods hiding in bark. however, by being equally adept at feeding head-down or head-up, it finds insects that a woodpecker might miss:

Common Water Strider (likely Aquarius remigis) emerged from its winter hiding. These are predators and scavengers of insects trapped on the surface of slow-flowing streams. As a “true bug,” it has evolved to exploit surface tension. However, surface tension alone doesn’t keep it dry; the secret lies in the dense, hydrophobic hairs on its tarsi. These trap air to act as tiny “dinghies,” preventing the legs from being wetted by capillary action:

Crocus flower (likely a Woodland Crocus, Crocus tommasinianus). The flowers emerge before the leaves, which then die back in late spring after accumulating enough biomass for the year. This adaptation to montane meadows and early forests allows them to bloom early, while withdrawing underground provides a defense against browsing:

Northern Mockingbird (Mimus polyglottos) picking bittersweet fruit (likely the introduced Oriental Bittersweet, Celastrus orbiculatus). The fruit is indeed slightly sweet—a fact I confirmed before spitting it out, as they are reportedly toxic to humans. As they say: don’t try this at home; try it in nature instead:

After the meal, the mockingbird sits quietly in a nearby bush. They mimic other birds’ calls, possibly to fool rivals into thinking a territory is already occupied. It doesn’t work on me, though—I can always tell the original bird from the imitation:

Snowdrop (Genus Galanthus), another Eurasian immigrant. Most of the plants in these pictures were introduced from Eurasia to the Americas; however, with the exception of the Bittersweet, they are generally not considered invasive:

A Jumping Spider. I can’t vouch for the exact ID, but it resembles Phidippus princeps. While not my best shot, it’s worth noting that, like all others in this series, it was taken with a single lens (Canon RF 100-500mm)—a blessing for a lazy photographer.

An Eastern Gray Squirrel (Sciurus carolinensis), looking lean after winter and digging for roots and grubs in the lawn. This species is an unwelcome sight in Europe, where its introduction is displacing the native Red Squirrel. But can we really blame them? They are simply good at being squirrels. It is entirely a human fault that geographical barriers are collapsing. In this “Homogecene” era of a connected world, the total number of species will inevitably decline:

Readers’ wildlife photos

March 15, 2026 • 8:30 am

Mark Sturtevant has returned with some excellent arthropod photos. Mark’s caption and IDs are indented, and you can enlarge his photos by clicking on them. Note that his stacking method is time-consuming; the third picture, he says, took “weeks,” and he’s still not finished.

Here is another set of local insect pictures, all manual focus stacks from either a staged setting from where I live in eastern Michigan, or at a local park.

The first was a visitor at the porch light. This beetle is a female stag beetle (Dorcus parallelus), and I was surprised about the ID because it was barely an inch long. Males of this species have mandibles only slightly larger than those in females:

The next picture is a Longhorn Beetle, Astyleiopus variegatus:

Next is a scene of symbiotic interactions between aphids and ants, where the aphids bribe the ants into protecting them by producing sugary secretions. The ants appear to be New York Carpenter Ants (Camponotus novaeboracensis), and I don’t know why they are called that since the species has a very wide range in the U.S. They are here tending aphids of an unknown species on a thistle plant. This picture is in a way impossible since an extreme macro picture like this cannot have much depth of focus, and it is also impossible to extend focus by conventional focus stacking since ants never sit still. So I’ve been spending weeks extending the depth of this picture from bits and pieces of several pictures. I am still not done doing this, but Mark needs a break so out it goes, into the public:

Dragonflies are next. These too are quick manual focus stacks but with a telephoto lens. Probably my favorite field for photographing dragons is a two hour drive away, but it is worth it because there is a field that is swarming with many species, including species that I don’t see elsewhere.

The first of these is a Common Green Darner Anax junius, which is a common species but what was exciting for me was that this is a male. Females land. Females are so easy to photograph that I usually don’t even bother. But males? No. Males fly pretty much all day, and I seldom get a chance with them:

But the best reason to visit the “dragonfly field” are its Clubtail dragonflies (Family Gomphidae). The main flight season for Clubtails is June, so that is when I make a point to visit the dragonfly field where there are ten documented species from this family. I have photographed all but two from there. Clubtail dragonflies tend to be marked in yellow and black, and they have a thickened end on their abdomen. But not all species have this color scheme, and some are more ‘club-tailed’ than others. A couple things to like about them as a group are the many species, and their reliability for perching on or near the ground. This is in stark contrast to certain other dragonflies (i.e., male Green Darners!)

The first of these are some of the ‘big-club’ Clubtails, and we start with a Midland Clubtail (Gomphurus fraternus):

The next is the impressively clubbed Cobra Clubtail (Gomphurus vastus):

And here is another one, the Skillet Clubtail (Gomphurus ventricosus), which is perched on Poison Ivy. Just to make things interesting, much of the ground cover in the dragonfly field is Poison Ivy. You should not even touch this stuff:

Do you see the differences in the above three species? Me neither! But upon close comparison, there are small differences in their markings that can be discerned. Most of the time when I am out there, I don’t know what big club species I am photographing.

Not all Gomphids are like the above. Here is a Lancet Clubtail (Phanogomphus exilis), which is probably the most common Gomphid in this park:

And here is an example of a very different dragonfly in the clubtail family, the Rusty Snaketail (Ophiogomphus rupinsulensis). There is another species of snaketail in the field, but it is rare and I have yet to see it. Just another reason to make the drive every June:

Now all of the above species of dragonflies are under 2” in length, so considerably shorter than your little finger. But dragonfly field hosts the largest Clubtail in the U.S. called the Dragonhunter (Hagenius brevistylus), which is about 3.5” long — the length of your index finger.

Does that still seem small? I promise if you see one you will stop and stare. Everyone does, because in the field they look big. The Dragonhunter is not even the largest of our dragonflies but they are probably the heaviest. Dragonhunters get their common name from their habit of eating other dragonflies. Admittedly, most dragonflies do that, but Dragonhunters seem to have a reputation for it. Even though I have seen many dozens by now, they always get my undivided attention when one goes cruising by:

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.
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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: