Readers’ wildlife photos

June 30, 2022 • 8:00 am

I have a few submissions as a backlog, but would surely appreciate more. Send in your photos!

Today’s contribution is from regular Mark Sturtevant, who’s never let me down.  His captions and IDs are indented, and you can enlarge the photos by clicking on them. Mark also notes that if you want to see more of his work, go to his Flickr page.

Here are some caterpillar pictures taken 2 years ago (I am terribly behind). All were found in various parks in eastern Michigan, which is where I live.

First up is a catalpa sphinx moth caterpillar (Ceratomia catalpae). I used to see lots of these when I was growing up, but I think I am too far north for them here.

Next are pictures of promethea moth caterpillars (Callosamia promethea) at different stages. They grow into a large-ish Saturniid moth that looks like a miniature cecropia moth. I can routinely find promethea cats at certain parks, especially if I inspect tulip trees. The smallest is next to a ray spider egg sac, which is a common cobweb building spider. The largest caterpillar is the size of your thumb.

Eastern Panthea caterpillarPanthea furcilla. I was completely stumped by the ID on this one, even though a caterpillar feeding on pine should be a major clue. But the kind folks at BugGuide helped me out in a jiffy.

Slug caterpillars have extremely reduced or even vestigial legs. These two could barely move. First is the larva of the yellow-shouldered slug moth, Lithacodes fasciola. Next is the amazingly camouflaged skiff slug caterpillar (Prolimacodes badia). I have never seen this species before.

Here is a looper caterpillar Caenurgina sp. These are common in tall grass.

And finally we have the invasive European gypsy moth (Lymantria dispar dispar). The Entomological Society of America has recently moved to de-list this name, as it was deemed offensive. The name “spongy moth” is proposed to be its new common name in North America. In any case, the species has been in my area of Michigan for several years. I used to see one or two a season, but now they are becoming extremely common. Here is a caterpillar. Mature caterpillars like this one are common on tree trunks, and here they will form a flimsy cocoon that is protected by their irritating hairs. It’s common to see several cocoons, some piled on top of each other, lining the furrows of tree bark.

Male moths are often seen perched alertly like this, using their ginormous antennae to sniff out female pheromones. One must admit that their headgear is impressive.

Females are rather odd. They don’t fly but instead continue to rest on tree trunks near their cocoons. Once mated, they make an egg mass that is covered by body hairs as shown here. This tree was dotted with females as far as I could look up, and all the trees nearby were just like it. Here they will sit until they die.

Females in my area tend to have asymmetrical wings, but they don’t fly so it does not matter. Their egg masses have helped gypsy moths to spread across the Eastern US via transport on timber, firewood, and on anything else that moves.

Gypsy moths were introduced into the Eastern US in the 1800s by an idiot who wanted to see if they could be interbred with silk moths. The larvae feed on a very large range of hardwood tree species, and when their populations reach plague proportions they will do considerable damage by defoliation. That has not happened here as far as I’ve seen, but I don’t know what the future will be.  Perhaps readers living in the Eastern U.S. can apprise us about what it’s like now.

On a brighter note, I do see a lot of dead gypsy moth caterpillars. Large numbers succumb to what I suppose is a bacterial disease, and so later in the summer I often heartened to see lots of them hanging limp and dead like this one.

In closing, I am inspired to paraphrase Bette Davis.

“One should never say bad things about the dead.
You should only say good.
This gypsy moth caterpillar is dead.
Good. “

Reader’s wildlife tale

June 22, 2022 • 8:00 am

Today we have another combination story and biology lesson from Athayde Tonhasca Júnior, this time recounting how bumblebees can use electricity and the buzzing of their wings to find flowers and effect pollination. Athayde’s tale is indented, and photos, which you can enlarge by clicking, are attributed.

May the Force be with the bee

If we are asked how a bee finds a flower, we think of smells, colours, shapes and textures. These are important sensory signals, but there is another one whose relevance we are beginning to understand: electricity.

The platypus (Ornithorhynchus anatinus), a few fish and amphibians, and some ants, cockroaches, mosquitoes and fruit flies have the ability to detect external electric forces. But vertebrates need water as a conductive medium, while most insects respond only to unusually strong electric fields such as those generated by high voltage power lines. Bumble bees, however, have a sparking story to tell.

Now and then the thunder from a lightning bolt or the shock from a car door jolts us to the realisation that we are components of the Global atmospheric electrical circuit; our world is an immense electric motor. On a calm day, the air is positively charged, while the ground surface and any object connected to it – plants included – have a negative charge. So flowers have a slight negative charge in relation to the air around them. Flying insects experience different physical forces: as a bee buzzes along, electrons are stripped off its body by friction with the air, creating a surplus of positive charges. When the bee approaches a flower, she* attracts the negatively charged pollen grains. The grains stick to the bee, sometimes jumping from the flower even before the bee lands. These electrostatic forces are a great aid to pollination.

—–

*”She” because a worker honey bee is a sterile female. Apis mellifera sex has some quirks: embryos can develop as males through gene editing; populations of Cape honey bees (Apis mellifera capensis) reproduce without males; and some bacteria such as Wolbachia spp. change the sex of their arthropod hosts, including Hymenoptera (bees, wasps and ants). Nonetheless, their sex is typically binary, just as in Homo sapiens.

—–

Fig. 1. An electrifying encounter: a positively charged bee approaches a negatively charged flower © Hooven et al., 2019. Molecules 24, 4458.

Fig. 2. Pollen clinging to a bee © Ragesoss, Wikimedia Commons.

But flower power reaches shocking levels for the buff-tailed bumble bee (Bombus terrestris), and probably for other bumble bees as well: they are able to sense the weak electric field around a flower. No one knows exactly how they do it, but mechanoreceptive hairs must be involved. These special hairs are innervated at their base, so they detect mechanical stimuli such as air movement and low frequency sounds. Apparently, the flower’s electrical field moves the mechanoreceptive hairs of an approaching bee, similar to the way a wiped rubber balloon makes your hair stand on end. This hair movement is processed by the bee’s central nervous system and gives information about the shape of the electric field. It works just like Uri Geller’s mystical aura, except that the bee is not a fraud and its powers are not mystical.

Fig. 3. A buff-tailed bumble bee worker with a transponder attached to its back to track it with radar © Meadows, 2012. PLoS Biol 10(9): e1001391.

Fig. 4. Hairs provide thermal insulation, collect pollen and help bees sense air motion, sounds and electricity © Kevin Mackenzie, University of Aberdeen. Attribution 4.0 International (CC BY 4.0).

But bumble bees’ capacity to detect electric forces may go beyond recognising flowers’ sizes and shapes: they could use the information to maximise foraging trips. Once a positively charged bee lands, the flower’s electric field changes and doesn’t go back to normal for about two minutes after the bee leaves. Researchers believe that an altered field warns the next bee that the flower is temporarily depleted of nectar; it’s like turning off a ‘we are open’ neon sign. So the next bee may as well buzz off to another flower with sufficient negative charge and a decent volume of nectar.

Bees and other insects detect ultraviolet and polarized light, and use magnetic fields for navigation. Sensing electricity is one more way their world is experienced differently from ours. And the relationship of bees with physics has other important implications, some of which affect our food supplies.

For most species of flowering plants, fertilization depends on the transfer of pollen from the male anthers of one flower to the female stigma of another. For the majority of those flowers, pollen is released through the splitting open (dehiscence is the technical term for it) of mature anthers. But for approximately 6% of the world’s flowering plants, pollen is kept locked inside non-dehiscent anthers and accessed only through small openings – pores or slits – in their extremities. We refer to them as poricidal anthers.

Fig. 5. Left: stamens, consisting of filaments and anthers. André Karwath, Wikimedia Commons. Most flowers release pollen by the splitting of the anthers along a line of weakness (top right); some only do it through a small hole or pore (bottom right).

Sometimes the whole flower has a poricidal arrangement, as it is the case for the tomato and related plants (Solanum spp.). Pollen is concealed inside a cone-shaped cluster of fused stamens and can only be released though a pore at the tip. Botanist say these flowers have a solanoid shape, after the name of the plant genus.

Fig 6. Solanoid-shaped tomato flowers © Muffet, Wikimedia Commons.

Extracting pollen from poricidal structures is not easy, but some bees know a way to do it.

A bee lands on one of these flowers, bites an anther and curls her body around it. She then lets out bursts of fast contractions and relaxations of her thoracic muscles – those muscles used for flying, but here the wings remain still. The contractions produce cyclical deformations of her thorax that last from fractions of a second to a few seconds: think of a body builder flexing his pectoral muscles really, really fast. These movements generate vibrations that are transmitted to the anther, causing pollen grains to fall though the apical pores and land on the bee’s body, adhering to it with the aid of electrostatic forces.

Fig. 7. A bee engaged in buzz pollination © Bob Peterson, Wikimedia Commons.

This head-banging pollen-harvesting manoeuvre generates a high-pitched buzz, hence it is known as ‘buzz pollination’; or as ‘sonication’ in technical reports. A physicist or an engineer could point out that this mechanism is not strictly sonication because it’s not sound that agitates and extracts pollen, rather the bee’s vibrations on the flower. But ‘sonication’ is the term commonly adopted, so we will keep it. Bumble bees (Bombus spp.), carpenter bees (Xylocopa spp.), and some other bees can buzz pollinate: honey bees (Apis spp.) and most leafcutter bees (Megachile spp.) cannot. And apparently only females know the trick; males have never been recorded buzz pollinating. Watch the whole sequence of events here (buzz pollination from 0:49) and here.

Plants with poricidal floral morphology are distributed across at least 80 angiosperm families, which suggests that buzz pollination has evolved independently many times. This has probably been helped by bees’ readiness to buzz for other reasons such as warning enemies, compacting nest materials, or cooling/warming their nests by beating their wings.

“Buzz-pollination syndrome”, the name given for this plant-bee association, is not just a biological curiosity. It makes a huge difference for crops such as tomatoes, raspberries, cranberries, blueberries, aubergines, kiwis and chili peppers. These plants don’t necessarily need buzz pollination to reproduce, but they produce more and better fruit if they are buzzed because more pollen is transferred and more ovules are fertilised.

In the late 1980s, Belgian and Dutch companies developed techniques to rear at a large scale the buff-tailed bumble bee, the ultimate buzz pollinator. Local producers of greenhouse tomatoes began replacing costly mechanical pollinators with boxes containing bumble bee hives, and a global, multi-million pound industry was born. Today, all ordinary tomatoes bought in a European supermarket have matured with the help of commercially reared bumble bees (they also transmit diseases to wild bees, but that’s a story for another time).

Fig. 8. A commercial bumble bee hive used in greenhouses © Elaine Evans, The Sustainable Agriculture Research and Education.

We may see pollination as a harmonious relationship where plant and insect go out of their way to help each other, but this is mistakenly romantic. A bee aims to take all the flower’s pollen: pollination happens because a few grains are dropped or rubbed off by accident. And a plant produces as little nectar and pollen as necessary to entice a flower visit. So the association between pollinators and flowers is best described as a mutual exploitation.

Buzz pollination fits nicely into this scenario. Poricidal anthers prevent excessive pollen expenditure by rewarding only a few specialist pollen gatherers, which increases the chance of pollination. Plants with poricidal structures typically secrete little or no nectar but their pollen is rich in protein, which convinces a bee to go to the trouble of buzzing to gain a small dose of the yellow stuff. It’s a clever and efficient trade agreement in the pollinators’ world.

Readers’ wildlife photos

June 15, 2022 • 8:00 am

Well, folks, we’re going to run out of photos by the weekend, so if you want this feature to continue, and have some good photos, send ’em in.

Today’s batch includes some lovely arthropod photos by regular Tony Eales from Queensland. His notes and IDs are indented, and you can enlarge the pictures by clicking on them.

I have been trying to get good at taking intimate portraits of insects and spiders where they are looking right down the barrel of the camera, with varying success. Here’s a few of my more favourite ones.

The best I’ve achieved, in my opinion, so far is this portrait of Myrmecia brevinoda, the Giant Bull Ant. At 35mm and armed with large jaws and an impressive sting, these are terrifying looking ants but actually they are very calm. They are entirely nocturnal and construct fairly large mound nests with multiple entrances in wet forests. I was able to sit right beside their nest and observe the colony doing maintenance without even a threat display let alone a sting.

Another large rainforest ant is Notostigma foreli. Workers are around 15mm long and quite robust. They are in the subfamily Formicinae, and as such do not have a stinger. These ants defend themselves with sprays of formic acid, but generally in interactions with large creature like ourselves they tend to just run. Like the Giant Bull Ant, they are nocturnal.

Other good subjects for front on shots are Jumping Bristletails. This one is a member of the Rock Bristletail family Meinertellidae.

Not only do you want a subject that will keep still, but for a really nice close-up it’s good if they have a fairly flat face. This reduces the need for photo-stacking which can be a bit of a pain and hard to do with live subjects that might move between shots.
An obvious candidate is the so-called Flat-faced Longicorns sub-family Lamiinae. This one is Rhytiphora albocincta, a fairly common species that feeds on acacia.

Another one I love to get in face-on shots is a small treehopper with a large head adornment Eutryonia monstrifera.

Raspy crickets also photograph well head on. In fact some will face off against threats and display with their wings, like this Nunkeria sp.

One of the more difficult ones for me are harvestmen, but I do love their little eyes up top. No idea of the ID for this one.

But the best all round subjects for front on portraits are spiders. No wavy antenna, no protruding mouthparts and sit as still as a rock.

Menneus sp.

Poltys sp.

Simaetha tenuidens:

 

Readers’ wildlife photos

June 13, 2022 • 8:00 am

Send in your photos lest this feature die!

Today’s photos come from reader Mark Sturtevant, specialist in arthropod photography. His IDs and text are indented, and you can enlarge his photos by clicking on them.

Here are more pictures taken in 2020.

One day while hiking in the woods, a large flying beetle made a noisy passage across the trail. I managed to knock it down. This is Osmoderma scabra, and it’s only slightly smaller than a walnut. 

After a few minutes it had enough, popped out its wings, and lumbered away through the air:

I recently showed a group of strange insects called bark lice. They’re in the same order as parasitic lice, but bark lice are more into feeding on lichens and algae. Some bark lice have wings; here is a handsome example of one. It is Cerastipsocus venosus

Bark lice are pretty alert and fast. But evidently the one shown in the next picture was not quite fast enough. Based on some details like the relative length of the legs, my guess is that the spider is one of the running crab spiders (species unknown). It was quickly hauling its prey along the twig. 

An extremely common visitor to our porch lights is this lovely little Geometrid moth known as the green pugPasiphila rectangulata. Cherry trees are one of their host plants, and we do have one, probably explaining why I see them so often. 

Let’s stay with the Lepidoptera. Next is a lovely Virginia ctenucha moth (Ctenucha virginica), a species found along wood margins. They resemble the closely related yellow-collared scape moth that frequents fields, and together they are part of an extensive mimicry complex that includes several orders of insects. Some members of the complex are distasteful, or they sting, and others are imposters. 

Next up is a caterpillar that was clearly preparing to form a chrysalis. Spiny caterpillars can be hard to identify, but I kept this one and it later emerged as a grey comma butterfly (Polygonia progne). 

And next is that same butterfly with recently expanded wings after emerging from its chrysalis. The reason for its common name is because of the comma-shaped mark on the underside of the wings. The upper side of their wings are mostly orange, but they spend much time sitting with wings closed on the ground among the dead leaves. In this circumstance, they are nearly impossible to see! 

Next up is a little planthopper called Acanalonia conica. These cute little insects are amusing to photograph, because when they realize they are being watched they deviously move to the back of the twig. The trick then is to extend a finger behind the twig, and that makes them sidle back out to sit in plain view. 

The house centipede (Scutigera coleoptrata) is a fairly cosmopolitan species that favors living in houses. As a result, many people know what it’s like to live with house centipedes. Let’s see. . . they attain a size that makes them a bit unnerving, they move fast, and they do have a tendency to suddenly dart out across a wall while you’ve settled down for the evening. I think that about covers it. Folks who live with house centipedes always have strong opinions about them, although they really cause no problems.

Here are some photographs of one that are actually focus-stacked from dozens of pictures taken during a staged setting on the dining room table. Lights were kept off, save for a lamp, and that helped keep it calm. Even so, I am rather surprised this even worked. A few times it did zip away into the dark surroundings, and it was challenging to find again. 

Thank you for looking! 

Readers’ wildlife photos

June 9, 2022 • 8:00 am

Today we have a batch of lovely butterfly photos from reader Ruth Berger. Her notes and IDs are indented, and you can enlarge the photos by clicking on them.

I am sending an unspectacular collection of Palearctic butterflies today. All photos taken in Frankfurt, Germany, in the vicinity of the mostly defunct chemical industry near the Main river, with a small 28mm automatic camera. I’ll start out with the one butterfly every European knows, almost the only local species that comes close to tropical butterflies in flashy beauty, Aglais io, the peacock:

The rose-tinted, white-streaked stone in the background (see lower right hand corner) is early triassic Main river sandstone, used a lot in Frankfurt’s older architecture. Here is a bunch of peacock caterpillars:

Butterfly number two is (probably) Ochlodes sylvanus, Large Skipper in English, taken moments before rainfall in an unmowed clearing surrounded by thickets. I love its warm rust color:

Two paces further along the clearing, I saw this one. It’s Melanargia galathea, fittingly called chessboard butterfly in German [JAC: “Marbled white” in English], but seems to have no common name in English. Like Ochlodes sylvanus, it needs unmowed grassland to thrive.

Its less pretty woodland “sister species”, metaphorically speaking, is Palarge aergeria, the speckled wood, “wood boardgame” in German. I have only a smartphone picture of that one, even though it’s more frequent here than the grassland Chessboard:

Two small bluesPolyommatus sp., probably icarus, copulating in May:

They were at it a long time. Here is one of them resting afterwards, showing its blue upper side (must be the male, I guess):

The next one was sitting on the sandy riverbank, licking minerals. It’s Apatura ilia, the lesser purple emperor, looking somewhat the worse for wear probably from a bird encounter (a small piece of wing is missing). The brightness and hue of the color change massively with the angle of the light source in this species. Its caterpillars love willow, which grows nearby. I am told this used to be common, but I rarely see it.

Now to the other side of the color spectrum:

This is a species regularly found in and on the edges of woodland, Polygonia c-album or the comma, called simply c in German, because of the white comma or c on the underside of the wings. The arrow shows the name-giving c/comma. As you can also see here, the comma is camouflaged as a dry leaf when its wings are folded.

Fresh green leaf mimesis here, most closely resembling young leaves in Spring as well as the leaf undersides of the evergreen bushes this  species likes to hibernate in. It is, of course, Gonepteryx rhamni, the common brimstone. They hardly ever deign to sit with wings spread, so I don’t have a picture of the yellow (in males) upper side.

Another well-loved staple of temperate palearctic lepidofauna. — the small tortoiseshell, Aglais urticae (yes, there are nettles galore a few meters further on). This was taken on a mowed lawn that had been grassland full of diverse blossoms and wild bees two days earlier, mowed by the municipality out of pure spite against bees to keep things orderly.

Finally, from the Pieris genus (“whites”), whose caterpillars like brassica vegetables and have followed the food and European Homo sapiens to North America, I’ll show you a species that I think is less frequent in North America and prefers wild crucifers to cabbage, Pieris napi.

The light pink flower is (I think) Armeria maritima ssp. elongata, the tall thrift, a bit of a rarity in Germany. Here, it grows on a large early Holocene deposit of river sand officially designated as a nature reserve, which keeps the municipality from mowing as soon as flowers other than daisies dare to raise their heads.

Maybe you have noticed the absence of possibly the most beautiful European (circumboreal, really!) butterfly, the Old world swallowtail, Papilio machaon. Although officially widespread in central Europe, I haven’t seen a single one since early childhood.
That’s all for today!

Readers’ wildlife photos and stories

June 6, 2022 • 8:00 am

Today we have another photo-and-story tale by reader Athayde Tonhasca Júnior, this time about amazing ways that flowers have evolved to reproduce by taking advantage of insects. His tale of pollination is indented, as are the pictures (not his, but credited). You can enlarge the photos by clicking on them:

‘You WILL pollinate me!‘: pushy characters of the plant world

When an insect visits a flower, some pollen grains become accidentally attached to its body. The insect moves on and some of the pollen is transferred to the stigma (the part that’s receptive to pollen) of another flower, kicking off the process of plant reproduction.

Fig. 1. A typical flower:

Such a passive, leave-it-to-chance approach is not good enough for some plants. Evolutionarily speaking, they have taken the matter into their own hands by forcing pollen onto visitors.

The mountain laurel (Kalmia latifolia) is a perennial shrub native to the eastern United States and well known on the other side of the Atlantic as an ornamental. The anthers of the mountain laurel flower are attached to small pouches on each petal. As the flower matures, the petals curve backwards, pulling on the stamen filaments, which bend under tension.

Fig. 2. A mountain laurel flower with eight of its ten anthers inserted into pockets in the corolla and held under tension © Derek Ramsey, Wikipedia:

When a relatively large insect such as a bumble bee lands on the flower, it may trip on a filament, releasing the anther from its pocket and launching pollen into the air at great speed. As most of the pollen is flung towards the centre of the flower, researchers believe this catapult apparatus results in more pollen grains attached to bees.

Alfalfa or lucerne (Medicago sativa) has a similar mechanism: its stamen filaments are stuck together into a structure called a ‘sexual column’, which is held under pressure inside two bottom keel petals that are fused together. When a bee pushes on these petals, the column is released, springing upwards and slamming into the upper petals. This process is called ‘tripping the flower.’ When it happens, pollen falls on the flower’s female reproductive organ and also on the bee, which then moves on to another flower. Some bees such as the European honey bee (Apis mellifera) don’t appreciate being whacked by a plant, so they avoid alfalfa or learn to get to the nectar without tripping the flower. Farmers can’t count on finicky honey bees, so they rely instead on the alfalfa leafcutter bee (Megachille rodundata) because this species is not bothered by a slap or two. Follow the whole story in this video (flower tripping from 2:20).

Fig. 3. A bee visits an alfalfa flower, tripping it © Diana Sammataro, Sustainable Agriculture Research and Education:

The tricks performed by the mountain laurel and alfalfa are known as explosive pollen release, and similar devices have evolved in plants from several families. Insects are not always involved: sometimes plants rely on explosive pollination to launch pollen into the air so that it can disperse long distances and, with luck, drift towards a receptive flower.

Flower tripping is an ingenious mechanism, but it pales in comparison to the stratagem employed by Neotropical orchids in the genus Catasetum. These plants awed and puzzled Charles Darwin: ‘I have reserved for separate description one sub-family of the Vandeae, namely the Catasetidae, which may, I think, be considered as the most remarkable of all Orchids.’ (On the Various Contrivances by Which British and Foreign Orchids Are Fertilised by Insects, and on the Good Effects of Intercrossing, 1862).

Catasetum orchids are dioecious (either male or female) and display strong sexual dimorphism, that is, flowers of both sexes look different: so much so that male and female plants were once thought to be separate species. These flowers produce no nectar, but they secrete fragrances that are collected by male orchid bees (tribe Euglossini), possibly to use for attracting females: we don’t know for sure.

Fig. 4. Male (L) and female Catasetum arietinum inflorescences © Brandt et al., 2020. AoB PLANTS 12(4).

Fig. 5. Male (top) and female Catasetum arietinum flowers © Brandt et al., 2020. AoB PLANTS 12(4).

When a male orchid bee lands on a male Catasetum flower, it touches a pair of antennae-like structures that trigger the shooting of a sticky pollen blob known as pollinium against the unsuspecting visitor. It happens with such force that the poor bee is sometimes knocked off the flower. Watch the stunning (literally) speed of pollinium ejection here, which can reach 2.6 m/s. For comparison, a pit viper, another denizen of Neotropical forests, strikes at 1.6 m/s. We don’t know how the orchid does it, but apparently changes in electrical potential and tissue turgor are involved, similar to what happens with the sensitive plant (Mimosa pudica). Incidentally, Darwin never observed Catasetum flowers in the wild, but he reasoned that pollen ejection must be related to bee pollination.

Fig. 6. A male orchid bee © Alejandro Santillana, Insects Unlocked, Wikipedia:

The male bee is not only surprised, but ends up with a hefty load as well: a pollinium can make up 23% of its body weight. He does not like this rough treatment one bit, so he may avoid a male flower on the next visit and go instead for a female flower, which does not have a pollen-spitting attitude. That suits the orchid just fine: the switch increases the chances of the pollinium lodging itself in a specialised receptacle of the female flower, fertilising it.

Fig. 7. A male Eufriesea auriceps carrying a pollinium (indicated by the arrow) of Catasetum fimbriatum © Reposi et al., 2021. Protoplasma 258(5):

Some plants go beyond hurling pollen at unsuspecting visitors: they resort to coercive control.

In ancient Greece, nymphs were deities portrayed as gorgeous maidens who would hang around ponds, rivers and other outdoor spots. But their beauty was hazardous: just like those wicked mermaids, nymphs could lure a virtuous man who happened to be passing by, leading him to madness or perdition.

Fig. 8. Naiads (freshwater nymphs) abducting the Greek hero Hylas © John William Waterhouse, 1896:

Nymphs may have been the product of overstimulated male fancy, but they also inspired the name of the water lily plant family, Nymphaeaceae. And just like the Greek nymphs, some water lilies do engage in devious charming, sometimes with fatal outcomes.

The white water lily or fragrant water lily (Nymphaea odorata) is an aquatic plant from shallow lakes, ponds, and slow moving waters throughout the Americas. It’s a popular nursery choice for ornamental ponds and water gardens around the world, but its floating leaves can form thick mats of vegetation, sometimes preventing light penetration and retarding water flow. So this plant is considered invasive in some places.

When a white water lily flower opens, its female parts are shaped like a bowl with the stigma at the bottom. This bowl is surrounded by a wall of stamens and filled with a viscous liquid full of sugars and detergent-like substances (surfactants). If this rigging has the look of a trap, that’s because it is one.

Fig. 9. A white water lily flower © SanctuaryX, Wikipedia:

The fragrant flower – hence the epithet odorata – is irresistible to bees, flies and beetles. When a visitor lands, it falls into the bowl. It tries to pull itself out, but the slippery soup and the palisade of flexible stamens hinders escape. As the insect struggles, pollen attached to its body is washed off by the liquid. The pollen drifts to the bottom of the bowl where it comes into contact with the receptive stigma, pollinating the flower. The insect may eventually crawl out, or it may drown: it makes no difference to the white water lily. It’s got its pollen.

At the end of first day of blooming, the flower closes. When it opens again the next day, the stigma is no longer receptive and no fluid is produced, so visiting insects are spared a watery end. Instead, they can fly away covered with pollen if they drop by on the second or third day of blooming, when the stamens release the powdery stuff. This stigma-stamen asynchrony prevents self-fertilization. On the fourth day, the flower is pulled underwater, where the seeds mature.

Fig. 10. Sweat bees (family Halictidae) are common visitors to white water lilies © Wikipedia:

In South America, giant water lilies (Victoria spp.) take unlawful detention to another level. Their flowers attract and trap beetles until the following day, when they are allowed to leave loaded with pollen. Watch a time-lapse video of a giant water lily flower opening and closing over the course of two days. The flower opens during the receptive stigma phase, closes to entrap beetles, turns pink (pollen release phase), opens again to free its pollinators, then closes before sinking in the water.

By detaining insects temporarily, plants increase the probability of fertilization. This type of relationship is known as entrapment pollination, and molecular studies suggest this is one of the oldest pollination systems. Nymphaeales (the order consisting of water lilies and other plants) and beetles have been playing this game for approximately 90 million years. It has worked nicely for both gaolers and gaoled.

Readers’ wildlife photos

June 2, 2022 • 8:00 am

We’re suffering from a dearth of photos, and though I’ve intended to make this feature more sporadic, it is close to being on its last legs. If you have GOOD photos, please send them in. Thanks.  And let’s thank all the readers who go to the trouble to create these posts!

Today’s batch comes from regular Mark Sturtevant, who, fortunately, will always have photos. His captions and IDs are indented, and you can enlarge the photos by clicking on them.

Let’s start with some Hemipterans. The first three pictures are of an ambush bug (Phymata pennsylvanica). These are predatory insects that lurk in flowers to nab visiting pollinators. Although only about a quarter inch long, they are quite capable of taking a large bee. The pictures are focus-stacked from a few dozen pictures, taken with the help of the Helicon Fb tube and then merged with Zerene Stacker software.

Next up is a flat planthopper from the genus Cixius

And the last of the Hemipterans is my favorite planthopper, Apache degeeri. They are found by meandering down forest trails and carefully inspecting the underside of leaves. Here’s one of at least three species of Derbids that I find this way. They are reluctant to jump away, so careful handling produced this quick hand-held focus stack from a few pictures. 

Next up is the well camouflaged northern marbled grasshopper (Spharagemon marmoratum), which favors ground cover with lichens into which it disappears. The third picture is an adult. 

The unsavory looking flies in the next picture are a mating pair of bee-mimicking robber flies (Laphria sp.) These are common on the ground cover in the woods over much of the summer. 

The final picture is another suspicious looking fly. This is the scaly bee fly (Lepidophora lepidocera). They are nectar feeders as adults, but the larvae are parasites of wasps. 

Thank you for looking!

Readers’ wildlife photos

May 26, 2022 • 8:00 am

Today’s batch comes from regular Tony Eales from Queensland.  His notes and IDs are indented, and you can click on the photos to enlarge them.

One of my favourite habitats is leaf litter, I think because it is often overlooked by the general public unless you’re a little kid. Something about lying down in the dirt, watching what is going on brings back my childhood wonder at the variety of life all around us.

So here’s a random selection of leaf litter denizens from around Brisbane Queensland.

First a common little jumping spider called Bianor maculatus. These spiders live in open grass and leaf litter. I was out one day hunting for Peacock Jumping Spiders (Maratus sp.) but all I found was dozens of these little guys.

What they lack in colour they make up for in their charming way of constantly being on the move and waving their forelegs around like antenna. To me this seems to be the first steps towards ant-mimicry, which is highly advanced in some tribes of jumping spider.

It did this individual no good however because shortly after I took this shot it was nabbed and consumed by a wolf spider.

This strange beast is a Short-tailed Whip Scorpion, which is a small order of arachnids called Schizomida. There are only fewer than 250 described species and externally they are all very similar. Generally, the largest are 5-6mm long and are found in humid tropical and subtropical leaflitter and soil in Africa, Australia, Asia and the Americas. The most common genus in Australia is Brignolizomus and that’s likely what this one is.

They have no eyes, but are active predators using their antenna-form forelimbs to find and investigate prey and their relatively large pedipalps to seize, subdue and grind up their victims.

Another strange beast that is common in the litter is millipedes in the Bristle Millipede order Polyxenida. Probably Polyxenus sp.

And I always love finding these blue-legged beauties hunting through the sticks and leaves. Rhysida nuda, the Northern Blue-Legged centipede.

The leaf litter in Australia is the kingdom of ants. It’s nearly impossible to find anywhere without several species. This is a large Camponotus sp. that I’ve yet to identify.

This ant is perhaps my favourite but they are extremely difficult to photograph as they are always on the move. It is one of the so-called spider ants, Leptomyrmex rothneyi, found in subtropical rainforest leaf litter.

And another favourite is the Painted Strobe Ant, Opisthopsis pictus. These are less common in my area and tend to be in the drier open forests to the north and west. They have an odd stuttering gait that appears to be to confuse predators. It has been observed that they never walk with their strobe gait when inside their nests, only when out in the open.

The subtropical rainforest near where I live has plenty of species of snail but this one is the most spectacular. This is the Giant Panda Snail (Hedleyella falconeri). They are leaf litter specialists and are never found more than half a metre above the ground—unlike many of the other snails that regularly feed on the trunks and leaves of trees.

This is unsurprising given that an adult snail is the size of a tennis ball and a fall from any great height would be potentially fatal. They are under threat from collectors and the pet trade. They are almost impossible to keep in captivity as they require a high humidity and a thriving population of particular fungi on which to feed. Hence many are captured only to die in peoples’ vivariums.

Leaf litter in the open eucalyptus forest has many species of small orthoptera and this is one of my favourites. Macrotona mjobergi the Handsome Macrotona. Macrotona is a genus of spur-throated locusts mostly from Australia often associated with spinifex grasses.

Other common Hymenopterans in the leaf litter are various parasitoid wasps, the most common being velvet ants (Mutilidae), which is what I thought this was at first. However, as it turns out, this is Myrmecomimesis sp., a member of the cuckoo wasp family Chrysididae. Unlike many other cuckoo wasps (but like Mutilids), the females are wingless and spend their time hunting for Phasmid eggs in which to lay their eggs.

Phasmids in Australia produce seed-like eggs that are dropped into the leaf litter. Some have a part to the egg that is meant to be eaten by ants, who take the eggs into the nest where they develop in safety. These wasps run around manically tapping everything with their antenna looking for these eggs before the ants take them.

Another predator, this tiny Carabid beetle, Scopodes sp. hunting through for tiny prey, I’m guessing probably larvae.

One of those potential prey, defending itself with camouflage and silk with leaf-plate armour. One of the case moths in the family Psychidae. Maybe an early instar Lomera sp.

x

 

Readers’ wildlife tales

May 25, 2022 • 8:00 am

Today’s bit of enlightenment comes from Athayde Tonhasca Júnior, and is on a subject that makes some people squeamish. But read on!

‘Thick-headed undertakers in the night of the living dead’

If you watched Alien, you may have jumped out of your seat when the baby monster burst from the astronaut’s chest. But an entomologist may have nodded knowingly: ‘Ah, a human parasitoid!’ Indeed, the screenwriters acknowledged entomological inspirations for coming up with the alien’s life cycle.

Here on Earth, a parasitoid is an insect whose larva develops inside the body of a host (usually another insect), eventually killing it. This type of life history lies between a predator’s and a parasite’s: a predator such as a dragonfly takes several prey and kills them outright, while parasites such as lice, fleas and ticks live off hosts without killing them.

Wasps account for most parasitoid species, but quite a few of them are flies. These include the 800 or so species of thick-headed flies (family Conopidae). A look at one of them explains their common name, although some species look more like wasps or bees than flies. They are also known as bee-grabbers or conopids.

Fig. 1. A conopid fly © Fir0002, Wikipedia.

Thick-headed flies hang around flowers looking for a sip of nectar. But a female may have other ideas: she may be waiting for an opportunity to lay her eggs, which is bad news for a bee or wasp.

It goes like this: an unsuspecting bumble bee worker approaches a flower. A female conopid closes in and grabs the bee in mid-air. Still afloat, she pries open the bumble bee’s abdominal segments with her theca, which is a pad-like, hardened structure at the end of her abdomen. Sometimes attacker and victim fall to the ground, but the outcome is the same; the female fly lays a single egg inside the bumble bee and lets it go.

Fig 2. A female conopid with her menacing theca clearly visible © Hectonichus, Wikipedia.

The drama is over within seconds, and both insects fly away. The fly will stalk another quarry. But the bumble bee is done for.

The egg hatches and the conopid larva develops inside the bumble bee, consuming her innards. But the larva does not penetrate the host’s thorax, thus leaving her flight muscles intact. The bee carries on with her life, feeding and taking nectar back to her nest, although less and less efficiently as the parasitoid grows. Within 10 to 12 days her abdomen is completely taken up by the larva, which has nothing more to eat. The bee dies and falls to the ground (if you find a dead bumble bee with a swollen abdomen, conopid parasitism could be the causa mortis). The larva pupates and overwinters inside the bee’s body, and the adult emerges in the following year.

Fig. 3. A conopid puparium inside the abdomen of a Centris analis bee © Moure-Oliveira et al., 2019. The Science of Nature 106. 10.1007/s00114-019-1634-9.

Some conopids increase the chances of their pupae making it through the winter with a trick that may seem macabre to human eyes: they induce their bumblebee hosts to dig their own graves. In North America, bumblebees parasitized by the conopid Physocephala tibialis bury themselves in the ground just before popping the clogs. This grave-digging behaviour does not make a difference for the bee, but the parasitoid pupa is sheltered from cold and dehydration during winter months, and less exposed to pathogens and its own parasites. Hibernation in the soil also promotes larger and healthier adult flies.

Fig. 4. The grave-digging inducer Physocephala tibialis © Beatriz Moisset, Wikipedia.

But bees don’t take it lying down. When parasitism pressure becomes too high, some species reproduce later in the year to avoid peaks of conopid populations. And some bumblebees – like many other insects – secrete melanin, which encapsulates and suffocates internal parasites. It is estimated that melanisation kills up to 30% of conopid larvae.

Fig. 5. A larva with encapsulated wasp eggs © Nathan T. Mortimer, Illinois State University.

After a parasitized bumblebee has dug its burial pit somewhere in America, a cold, drizzly night falls over the land. All is quiet. Until in an apiary nearby, one of the resident honey bees (Apis mellifera) does something odd: she emerges from the hive and flies towards a streetlight glowing faintly in the distance. A few of her sisters follow suit, although some of them fall to the ground and begin walking around in circles, apparently confused. None of these night wanderers will ever return to the hive; soon they will all be dead. They have been victims of a parasitoid ominously named the zombie fly (Apocephalus borealis).

Fig. 6. A female zombie fly © Core et al., 2012. PLoS One 7(1): e29639.

This fly belongs to one of the largest insect groups, the family Phoridae. They comprise about 4,000 described species, but specialists believe this number represents a fraction of the total. Phorids look like fruit flies with arched backs, and when spooked they run away before taking flight. Such behaviours explain their common names: hump-backed flies or scuttle flies. They are everywhere, and have a variety of feeding habits such as saprophagy (they eat decaying organic matter), predation, and herbivory. One species is a serious pest of cultivated mushrooms.

Two groups of Phorid flies, the genera Pseudacteon and Apocephalus, are found mostly in South America and are charmingly known as ant-decapitating flies. A typical species approaches an ant from behind and uses its powerful, hooked ovipositor to inject an egg in the victim’s head or thorax.

Fig. 7. The hooked ovipositor of Pseudacteon curvatus, a decapitating fly © Sanford Porter, Wikipedia.

The resulting larva moves to the ant’s head, where it feeds on hemolymph (‘blood’) and tissues. Eventually, the larva consumes all the head’s contents, causing the ant to wander around erratically. In two to four weeks, the larva is ready to pupate. It releases enzymes that dissolve the tissues attaching the ant’s head to its body. The head falls off, and the fly pupates inside it before emerging as an adult. These flies are efficient ant killers, and therefore are promising biological control agents against invasive species such as fire ants (Solenopsis spp.).

Fig. 8. A) An ant-decapitating fly (Pseudacteon sp.) preparing to inject an egg into the thorax of a fire ant. B) A decapitated ant with a fly maggot consuming the contents of its head © Porter & Gilbert, 2005. International Symposium on Biological Control of Arthropods.

The zombie fly does not decapitate honey bees, but much of its life history is similar to those of its tropical relatives. It lays its eggs in the abdomen of the bee. The larvae feed on hemolymph and flight muscles, and when they are done, they leave the host to pupate outside. Up to 13 larvae have been observed coming out of a dead honey bee.

Fig. 9. A zombie fly ovipositing into the abdomen of a honey bee worker © Core et al., 2012. PLoS One 7(1): e29639.

Fig. 10. Two fly larvae leaving the host at the junction of the head and thorax © Core et al., 2012. PLoS One 7(1): e29639.

We don’t know why a parasitized honey bee abandons her nest, especially at night, to wander on a suicidal excursion. Her neurological wiring may have been highjacked by the fly, inducing the bee to seek a safer place for the development of the parasitoid’s eggs and larvae. The bee may have been forced out by her healthy sisters; or she left the colony on her own, acting on an altruistic instinct to avoid an epidemic.

Fig. 11. Four zombie fly pupae surrounding the dead honey bee from which they emerged © John Hafernik, University of Florida Entomology and Nematology Department.

The zombie fly is native to North America, where it has long been known to parasitize bumble bees and wasps. Then in 2009, there was an alarming discovery: the fly was also attacking honey bees in parts of the country. And there was more bad news to come. The zombie fly harbours the fungus Nosema ceranae and the Deformed Wing Virus, which are serious threats to honey bees. Researchers don’t know yet whether the zombie fly plays a role in the transmission of those pathogens to bees, but the possibility is worrying.

Conopids and zombie flies are some of the many parasites and parasitoids capable of changing hosts’ behaviour for their own benefit. Some wasps turn ladybirds into paralysed living shields over their eggs, and some fungi make ants climb up plants so they can release spores into the air. Perhaps the most notorious case is the effect of toxoplasmosis cells on rats and mice. Infected rodents become attracted to cat’s urine and are less likely to hide. This altered behaviour is a death wish: they became easy prey for cats, in which toxoplasmosis cells complete their development. Carl Zimmer discussed many other examples in his excellent Parasite Rex; you can read about some of them here.

Parasitism seems gruesome and cruel. Even Darwin was dismayed by it, as he expressed in one of his letters: ‘I cannot persuade myself that a beneficent & omnipotent God would have designedly created the Ichneumonidæ [ a group of parasitic wasps] with the express intention of their feeding within the living bodies of caterpillars.’* But such anthropomorphism is misguided and biased. Parasitoids, predators and parasites are regulators of the natural world: about 10% of all known insect species are parasitoids, although specialists believe this figure is a huge underestimation. They prevent excessive population growth, including of agricultural pests and disease vectors. Parasitism helps shape biodiversity and ecosystems, so it is not intrinsically bad or good. It is a characteristic of life on our planet.

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* This famous quotation inspired a team of ichneumonid specialists to propose in 2019 ‘Darwin wasps’ as a vernacular name for this group of insects, so that they may become better known and appreciated.

Fig. 12. A Darwin wasp © Charles J. Sharp, Wikipedia.

Readers’ wildlife photos

May 18, 2022 • 8:00 am

Today we have an assortment of diverse photos by Tony Eales from Queensland. His captions and IDs are indented, and please click on the photos to enlarge them.

By the way, if you have good photos you’d like to send me, see the link on the left sidebar of this site, “How to send me wildlife photos.”

I came across this Aseroe rubra Anemone Stinkhorn Fungus the other night. This fungus is relatively common here in eastern Australia but by daytime they have grown into a 100mm high tree-like shape with deep red tentacles and the light brown part collapsed into a dark brown-black goo. They start out as a white egg shape emerging from rotting mulch that then bursts revealing the tentacles. You can see the remains of the egg in the photo.

I don’t often photograph vertebrates but I’ve seen a few cool ones of late. This one is  or Red-bellied Black Snake. They are specialists of frogs and smaller reptiles. They are one of the more common snakes in my area but had their numbers reduced by the spread of the introduced Cane Toad (Rhinella marina), which is highly poisonous. Red-bellied Blacks are dangerously venomous but reluctant biters, even so, being very common they are responsible for a few bites every year.

For their size their venom is among the least dangerous of the Australian elapids with the only recorded deaths being early on and of questionable identification.  My most frequent encounters with them is to see the tail rapidly disappearing into the bush. It was good to have a calm subject to photograph.

Another lovely snake I found recently is Cacophis squamulosus, the Golden Crowned Snake—a rainforest specialist living in the leaf litter hunting insects and small reptiles. Again I normally see only a flash disappearing into the leaf litter, but this one was out on a fence at night time and I managed a few snaps before it retreated.

Another exciting find for me was this Lycid beetle larva. The larvae of these beetles are some of the strangest animals I’ve seen. I have no idea of the species and adult lycids are very similar looking to one another so I have a devil of a time getting them to species level as well.

But by far my favourite find recently was the wonderful Ordgarius magnificus AKA the Magnificent Bolas Spider. These are large spiders, the abdomen being about the size of the end of your thumb.  Their eyes are very strange, being perched on top of a thin red tubercule in the middle of their large cephalothorax.

By day they hide in a retreat composed of leaves and twigs lashed together [below] with a few strong web lines. Most people only see their (up to a dozen) 5 cm-long, dangling egg sacs, each containing up to 600 eggs.

Not only are they large and colourful, but their predatory behaviour is extraordinary. They hang at night from a simple web and create a dangling thread with large globs of sticky glue dotted along it. They exude a pheromone that attracts the male moths of one particular species. When they detect the vibrations of an approaching moth they swing the sticky bolus around and around which catches the moth. I am reliably informed that the vibrations from a nearby diesel engine running will also elicit this predatory behaviour.

The  hideout:

I found this one hunting, but my light disturbed it and it reeled in and reconsumed its bolus unfortunately so I did not get shots of the hunting behaviour.