Why Evolution is True is a blog written by Jerry Coyne, centered on evolution and biology but also dealing with diverse topics like politics, culture, and cats.
Today we have the life of a butterfly, with photos by Mary Rasmussen. Mary’s captions are indented, and you can enlarge the photos by clicking on them.
The Red Admiral Butterfly
I always leave a few Stinging Nettle (Urtica dioica) plants in my garden here in the Upper Peninsula of Michigan. The Nettles are popular with the Red Admiral Butterfly (Vanessa atalanta) but also feed a variety of other moth and butterfly caterpillars.
Like many Monarch butterflies, Red Admirals are migratory. Most northern Red Admirals are thought to migrate south each fall, but some may overwinter. Red Admirals do not survive the coldest winters and most of North America is re-populated by southern butterflies migrating north in the spring. They are a very welcome sight here in mid-spring:
Female laying an egg. The butterfly’s reproductive organs are located near the lower tip of the abdomen. You can see the tiny green egg that she will deposit on a Nettle leaf. The egg’s surface has a glue that will hold it on the leaf:
Macro shot of a Red Admiral egg on a Stinging Nettle leaf. You can see the hollow stinging hairs of the Nettle leaf. I’ve learned that I can grasp the plant while moving my hand upwards and not suffer any consequences. Moving your hand down along the plant is definitely not recommended.
Caterpillars feed primarily on plants in the Nettle family (Urticaceae). They sew a leaf closed around them to make a protective nest and then eat their way out. They do this several times while they are maturing:
The caterpillar hangs down and forms a “J” shape, signalling that it will soon pupate.
The chrysalis:
The newly emerged butterflies have brilliant coloration. Their underwings are particularly beautiful:
I use a Nikon D500 camera with Nikon VR 105mm f/2.8G macro lens. For the butterfly egg I used a Laowa 25mm f/2.8 2.5-5X Ultra Macro lens with extension tubes.
This guide has an index of the caterpillars and most useful is the index of food plants. Many times I have been able to identify a caterpillar by looking up the plant it is munching.
Today we have insect photos by regular Mark Sturtevant. Mark’s captions are indented, and you can enlarge his photos by clicking on them.
Here are more pictures from the previous summer. All were photographed near where I live in eastern Michigan, and most come from a single park about a two-0hour drive to the south of me.
In the woods of this park, there were many of these interesting caterpillars on the ground vegetation. I believe they are the larvae of the Red Admiral Butterfly (Vanessa atalanta), which has been a challenging species to photograph. On a return visit, I would like to bring some back to raise since I’ve never been completely satisfied with my pictures of the adults:
The woodland trail followed a lovely river, and periodically the woods would open up into a meadow. At one such riverside meadow was a stand of interesting flowers (maybe wild mint?) being worked over by the large black butterfly shown in the next 2 pictures. This was for me one of the most exciting finds of the whole summer! This, people, is the melanistic form of the Eastern Tiger Swallowtail Butterfly (Papillio glaucus). I swear this is the same species as the familiar black and yellow swallowtail! This dark form is always female, identified by the splash of blue on the hind wings. The melanistic Tiger Swallowtail is not recorded where I live, but it becomes more common to the south, via natural selection, because there it starts to overlap with the toxic Pipevine Swallowtail which it resembles. But only females can pull off the mimicry trick for some reason. Anyway, I was pretty much hyperventilating while taking these pictures. From the ventral view you can still see the faint Tiger Swallowtail stripes:
JAC: Species in which females mimic another toxic form but males keep the ancestral pattern are far more common than the reverse. Can you guess why males don’t evolve to change their pattern? I’ll put the answer in the comments later.
Turning up tree leaves hanging over a forest trail will commonly reveal something of interest. One leaf along this riverside trail had this weird Derbid Planthopper (Anotia uhleri). I am sometimes asked about the yellow thingies below the eyes of this insect. Those are the antennae, which tend to be oddly distinct in this group of planthoppers:
Another thing that one can find under leaves are insect eggs or recently hatched insects. Here is a group of Leaf-footed Bug hatchlings (Acanthocephala sp.), staying close together to amplify their colorful advertisement that they are chemically protected. Whenever I find these groups, I have to take a deep breath and just do my best. Step to one side, prepare the camera for an extreme close-up, and do some test shots on a random leaf to figure out the correct exposure. Then lift up the leaf again and frantically fire away as the nymphs scamper off:
Along the river bank of the park were some sandy areas, and on the sand were quite a few of these well camouflaged insects. This is a young Big-eyed Toad Bug (Gelastocoris oculatus), which are aptly named predatory Hemipterans that are entirely invisible until they hop:
Here are a couple more finds. This tiny beetle, about the size of a sesame seed, is the Basswood Leaf Miner, Baliosus nervosus:
And the unsavory face in the next picture actually belongs to a rather cute and mild-mannered Two-spotted Tree Cricket, Neoxabea bipunctata:
I’m not always sure which critter in this set was from that distant park that I mentioned. But this one sure was! There, I was delighted to find this large katydid known as the Common True Katydid (Pterophylla camellifolia), which is another insect that does not occur in my area. Despite their large wings, True Katydids are flightless. At dusk, this male will begin its song; with some imagination, it is described as sounding like: “Katy did! Katy did !! She didn’t! She did !!!” Readers who live in its range will know it well, as they can be fairly deafening. Here is one singing. If it doesn’t hurt your ears a little, you aren’t playing it loud enough:
And finally, for the heck of it, here is what I believe is a Northern Leopard Frog (Lithobates pipiens) although there is also the similar species called the Pickerel Frog. The two differ in the form of their spots plus some other details. We see some colorful frogs from far-off places on this website, but this domestic one is still quite lovely, I think:
Thank Ceiling Cat: two readers came through with photos when the tank was empty. Today’s lot comes from Leo Glenn, who sends photos from Costa Rica. His captions are indented, and you can enlarge the photos by clicking on them.
Here are some more photos from my recent trip to Costa Rica.
There are four species of monkeys in Costa Rica: the Central American squirrel monkey (Saimiri oerstedii), the Panamanian white-faced capuchin (Cebus imitator), Geoffroy’s spider monkey (Ateles geoffroyi), and the mantled howler monkey (Alouatta palliata). As we were spending most of our time in parks and nature preserves, we were hopeful that we would see at least one of the species. It came as quite a surprise to us, then, that while we saw no monkeys in any of the nature preserves, a family of mantled howlers moved Into the trees next to our rental house and spent around 45 minutes eating, lounging, and playing. It was an amazing experience.
Like cats, they were masters at relaxing in the most precarious of positions.
We enjoyed watching them use their prehensile tails to move among the branches, sometimes hanging from them to reach the choicest leaves, which make up 75% of their diet.
Another species that we were hoping to catch a glimpse of was a coatimundi. And just as we pulled into the Monteverde Cloud Forest Reserve, a South American coatimundi (Nasua nasua) strolled right across the parking lot.
Coatimundis, known locally as pizotes, are members of the family Procyonidae, the same family as raccoons, and they share many of the same traits. Unlike the more nocturnal raccoons, however, coatimundis are diurnal.
In the cloud forest, we came upon a nest of red-tailed stingless bees (Trigona fulviventris). Our guide said that the honey they produce is inedible, but it has been used traditionally for medicinal purposes. I couldn’t find any information on that, but I did read that the sticky resin they make to build their nests has been used by fishermen to caulk leaks in their canoes. Another occasion when I wished I had a longer lens.
A tree fern (Cyathea holdridgeana). I was particularly excited to see this, as I have been obsessed with paleontology since I was a child. Tree ferns, along with Lycopods and Horsetails, were the predominant “trees” in ancient forests, before our current trees evolved. This particular species grows at elevations of 2400-2800 m, much higher than most other tree ferns in Central America. I believe we were at around 2100 m on this tour.
A colorful group of caterpillars. I was unable to determine the species, but they appear to be a moth in the genus Euglyphis.
And finally, our rental house came with a cat [Felis catus], whose name was Linda.
Linda asking to be let in.
Below: Linda’s favorite activity, after we let her in (other than begging for something to eat). She was 17 years old, and growing deaf. Her meow was loud enough to wake the dead (something she liked to do at five in the morning outside our bedroom window). But she was otherwise spry and hale. Of course we fell in love with her.
We’re down to two or three sets of photos, so things are getting dire. If you have good wildlife photos, send them in now (but not between the 11th and 21st, when I’ll be gone). Thanks.
Today Tony Eales, back from his African safari, now sends us photos of African bugs. His captions are indented, and you can enlarge his photos by clicking on them.
As I said in an earlier post, there were not many bugs, June being well into winter in southern Africa. There were, however, still bugs and creepy crawlies of different kinds. Here are a few of them. Unfortunately I don’t really know much about most of these species but I’m reaching out to various places to learn more.
At the same camp I found this lantern fly, probably Druentia sp.:
I found this strange bark mantis in Chobe. It barely has the classic raptorial forelegs that are usual for mantises. Amorphoscelis sp.:
At the same camp we found this elongated assassin bug, Rhaphidosoma sp.:
This mantis, while more classically armed, was very weirdly adorned to help it blend into the background.Sibylla pretiosaCryptic Mantis:
We saw the evidence of a very unusual moth that could really only live in an area with thousands of grazing mammals like southern Africa. Ceratophaga vastella, the Horn Moth. Unlike the majority of moth larvae, these feed on mammal horns rather than plants. [JAC: the marks on the horns are caused by larvae; as Tony explained, “You can see the worm-like tunnels On the surface of the horn and empty pupal cases sticking out of the horn”]:
Here’s one of the major shapers of the landscape, Macrotermes sp. I don’t know if the species I photographed here are the same ones that are responsible for the large mounds that we observed, especially in the Okavango, but they are in the same genus. These termites are unusual in they are fungus farmers rather than eating the plant material directly:
Some of the more impressive insects I encountered were hymenopterans. Here is a Slender Tree Ant in theTetraponera natalensis species complex:
Stingless beesMeliponula bocandei, much larger than the Australian and Southeast Asian species I’ve encountered:
And of course, I found a wide variety of my favourite group, arachnids. Including my very first member of the Solifuges, or Sun Spiders. Apparently this family (Solpuginae) of Sun Spiders is called Common Romans. I’m not sure what that is about.
And these spiders were absolutely everywhere after dark. I was confused as by size and habit they seemed so much like the huntsmans (Sparassids) that I know from home, that I assumed that’s what they were. But in fact they were what are known as Flatties or Wall Crab Spiders (Selenopidae). I should have noticed the different eye arrangement. This one is probably Selenops sp.:
But my favourite spider was this impressive Wandering Spider (Ctenidae). As yet, I have no ideas about the genus but I’m asking a few knowledgeable folk about it:
Today we have a story and photo contribution about weevils by Athayde Tonhasca Júnior. Athayde’s captions are indented, and you can enlarge the photos by clicking on them.
See no weevil, hear no weevil
As the story goes, J.B.S. Haldane (1892-1964), British/Indian geneticist, evolutionary biologist and mathematician, found himself in the company of a group of theologians. On being asked what one could learn about The Creator from studying his creation, the atheist Haldane is said to have answered ‘an inordinate fondness for beetles.’ Haldane may have said something like that, and indeed a Great Architect of the Universe would have had to be partial to the order Coleoptera. With nearly 400,000 known species, beetles lead the biodiversity table, making up about 25% of all known animal species. But if the Almighty Creator liked beetles, he was especially fond of weevils (superfamily Curculionoidea): there are over 97,000 described species, of which 76,761 are snout beetles (family Curculionidae) (Global Biodiversity Information Facility). But we know these figures are gross underestimates because in poorly studied areas, i.e., most of the world, the majority of weevil specimens collected are members of unknown species.
Weevils are found practically everywhere, and almost all of them are plant eaters. They feed on plants from any terrestrial or freshwater habitats and on a range of tissues: roots, stems, phloem, fruits, flowers or seeds. Many species are among the most damaging pests of stored grain, field crops, orchards, ornamental plants and commercial forests. Weevils’ destructive potential can’t be overestimated. The boll weevil (Anthonomus grandis) wrecked the American cotton industry in the 1920s and 30s, then invaded South America in the 80s causing further mayhem. In the US, the Southern pine beetle (Dendroctonus frontalis) is able to wipe out thousands of hectares of pine in less than two years, while grain weevils (Sitophilus spp.) can completely destroy rice, maize, wheat, oats, and many other products stored in silos around the world. You may have had your own experience with weevils infesting a bag of flour or a box of pasta in your pantry.
Considering weevils’ charge sheet, we would be tempted to dump the lot in the ‘creepy crawlers’ category. But that would be hasty and unjustified. Only a tiny minority of weevils are harmful, while the great majority contribute to the functioning of ecosystems. One way they do this is by pollinating a range of plants.
Cantharophily (from the Greek word kántharos for beetle), or pollination by beetles, is not well understood or researched, despite being one of the first pollinating systems in the evolutionary history of flowering plants. With time, bees, flies and moths became the main pollinators, but many plants, especially of ancient lineages such as magnolias (Magnoliaceae), retained cantharophily. Some custard apple-related plants (Annonaceae), arums (Araceae), palms (Arecaceae) and orchids (Orchidaceae) are also pollinated by beetles.
Most beetles don’t handle pollination skilfully and gently: they plough through flowers, gobbling down nectar, pollen or petals, defecating as they go, often spilling more pollen than they eat – that’s why they are called ‘mess and soil’ pollinators. During these raids, beetles become contaminated with pollen grains, which are deposited on the next plant they visit. Weevils, however, have a more intimate and nuanced rapport with their hosts. They lay their eggs on the flowers, where their larvae will grow and mature by feeding on pollen, ovules, or other floral parts. By hosting weevils during a significant portion of their lives, plants are almost guaranteed being pollinated for the price of a fraction of their reproductive parts.
This type of mutualistic relationship is known as brood-site pollination or nursery pollination and it has been reported dozens of times for different groups of insects, mostly in the tropics; the interactions between figs and wasps and between yuccas and moths are two of the better known examples. In the case of weevils, hundreds of species have coevolved brood-site associations with a range of plants, but mostly with palms (family Arecaceae).
One instance of weevil-palm mutualism has particular relevance for its ecological and economic implications: the pollination of African oil palm (Elaeis guineensis) by the African oil palm weevil (Elaeidobius kamerunicus). Male weevils feed on the palm’s flowers and pollen, while females oviposit in the flower structures, in which the larvae feed and develop. You can watch the weevils in action.
When oil palm growers around the world, but mostly in Indonesia and Malaysia (the leading producers and exporters of palm oil), began to import the pollinating weevil in 1981, the industry changed radically. The beetle adapted well to its new habitats and boosted African oil palm pollination, which resulted in sharp increases in production, revenue and applications; palm oil made its way into margarines, chocolates, baked products, cooking oils, soap, detergents, cosmetics – you name it. The “million dollar weevil” had been found (Robins, 2021).
But as sociologist Robert K. Merton warned us, purposeful actions are bound to have multiple outcomes, some of them unanticipated. This law of unintended consequences (flippantly identified as Murphy’s Law) suited the case of the million dollar weevil to a T. Large-scale oil palm production resulted in massive deforestation that is destroying the habitats of large numbers of plant and animal species, and increased levels of erosion and pollution.
Fortunately, the introduced African oil palm weevil is an isolated case of ecological mishap. All other known examples of beetle brood-site pollination are mutualisms that help maintain biodiversity. Seres & Ramirez (1995) estimated that more than 45% of palms and herbs in some cloud forests are beetle‐pollinated, and Haran et al. (2023) have recorded at least 600 cases or suspected cases of palm-weevil interactions: the true number is likely to be much larger. We have the vaguest understanding of the pollinating services played by these weevils, but it mustn’t be something to sniff at considering that the number of Curculionidae species alone is almost four times bigger than the number of bee species (~20,000).
Palms and many other types of plant pollinated by weevils are sources of food, building materials, cosmetics and medicines; a good portion of those products are consumed locally or sold abroad, generating much needed income to developing countries. Not so bad for those maligned big-conked characters.
According to biblical sources, Noah’s ark had ~42,500 m3 of available space, the equivalent of 570 standard railroad stock cars. We can deduce that Noah’s ship was not a run-of-the-mill zoo because most species competing for a berth comprised parasites and weevils. Art by Simon de Myle, 1570. Wikimedia Commons:
Posting may be light today as it’s a busy day: I have to feed the dorm ducks, giving them extra water because it’s going to be hot (93° F, 34° C), and then we have to meet with Facilities this afternoon to see what the fate of Botany Pond is. I’m worried as they mentioned “duck deterrents” during the mating season. No baby ducks? Unthinkable! Besides, since the pond will be full of water there is no way in hell to keep ducks away from it.
Today sees the return of regular Mark Sturtevant, insect and arthropod photographer extraodinaire. His captions are indented and you can enlarge his photos by clicking on them.
Here are more pictures that are mainly from the previous summer. The first two pictures are nymphs of a predatory Hemipteran known as the Masked Hunter (Reduvius personatus). As nymphs, they decorate themselves with dirt or sand for concealment. The third picture shows an adult Masked Hunter. Although the nymphs are normally very difficult to find, both the nymph and the adult were found at my porch light at night. Most members of this family (Reduviidae, or assassin bugs) are slow and plodding, but Masked Hunters are surprisingly quick on their feet.
A “fen” is a special kind of wetland that is a bit different from what one might call a bog or a marsh. I have learned that defining these things is a delicate matter, but as I understand it a fen is sustained by water that percolates up from limestone, resulting in an alkaline pH. Fens are characterized by an array of specific and interesting plants (and insects, as we shall see). There is a park about 15 minutes from my house called Seven Lakes State Park, and it has several fens. One of them can only be accessed by a Secret Path through the woods, and I’ve never seen a trace of anyone else there so it is now “Sturtevant’s Fen”.
Once out of the woods, the higher ground surrounding Sturtevant’s Fen is sprinkled with a lovely orchid called the Grass Pink Orchid, Calopogon tuberosus, as shown in the next picture. This orchid is famously described as the “upside down orchid”, but that is all part of a great deception. Orchid flower anatomy is a bit different from other flowers, and I hope I get this right (feel free of course to correct me, someone). In orchids, the sepals and petals tend to look like petals, and male and female reproductive organs are fused into a single structure called the column that can be seen in this orchid as the curved structure at the bottom. But what about those bright yellow thingies on the top-most sepal that look like male anthers? They are the deception part of the story, and also why this is the upside- down orchid. What appears to be a flashy set of anthers that promise a rich pollen reward are actually lures, aimed at tricking bees. When a bee visits this flower, it will likely go after the false anthers, and this causes the sepal they are on to suddenly hinge down and whack the bee against the column. This results in sticky and inaccessible pollen sacs attaching to the back of the bee. The bee flies off, and if it visits another of these orchids it will likely make the same mistake by going after the false anthers (bees are not smart). It will get whacked again, and this results in the pollen sacs being transferred. Darwin would have loved this orchid!
Out on the fen proper, the ground becomes firm sand that is always under about a quarter inch of water. Your shoes will get wet. And among the dense stands of coarse sedge grasses are three different species of carnivorous plants! Most obvious among them are the numerous Pitcher Plants, Sarracenia purpurea, which are shown in the next two pictures. Early in the season, these have tall flower stalks with weird flowers. A feature of carnivorous plants is that they do not want to eat their pollinators, so they keep their flowers well away from their insect traps. I wonder if the weird shape of the flowers themselves are also designed to keep their pollinators from falling to their doom. Of course, the watery trap in each pitcher plant holds syrupy water with digestive juices and often lots of dissolved insects. Once I found a live maggot living inside one that was evidently there to feed on trapped insects.
Crowding around the bases of the pitcher plants are Sundews, another insect-eating plant shown in the next picture. They of course trap and digest insects with sticky hairs on their leaves. The Sundew here I think is Drosera rotundiflora. They too try to not kill their pollinators with flowers on tall stalks, but I have yet to see those.
How those two carnivorous plants trap prey is pretty obvious and well known. The third carnivorous plant is more subtle about it. Dotting the fen landscape are much scarcer but very distinct flowers, one of which is shown in the next picture. These belong to the horned bladderwort (Utricularia cornuta). Bladderworts are more aquatic, and they have tiny specialized vessels among their roots that trap and digest small aquatic prey.
But for me, the real attraction of my private fen is a very special little dragonfly. These are Elfin Skimmers (Nannothemis bella), and they are by far the smallest dragonfly in the U.S. The world’s smallest dragonfly is a close relative found in China, and it is not much smaller! Elfin Skimmers abound in Sturtevant’s Fen, which is as it should be. First, here is a female. These are suspected to be wasp mimics. Next is a male.
Although those tiny dragons were perched on grass blades, it may still be hard to convey how incredibly tiny these are for a dragonfly. So just for this post, I made a special trip back to Sturtevant’s fen with a butterfly net and very carefully captured the young female shown in the last picture. Look at your index finger. The body of that little dragon will hardly stretch across the width of your finger!
Today we have a photo-and-text story by Athayde Tonhasca Júnior. His topic: plants and gnats. His text is indented, and you can enlarge the photos by clicking on them.
Pesky little helpers
“He could put up with his meaningless office-life, because he never for an instant thought of it as permanent. God knew how or when, he was going to break free of it (…) The types he saw all around him, especially the older men, made him squirm. That is what it meant to worship the money-god! To settle down, to Make Good, to sell your soul for a villa and an aspidistra!” (Keep the Aspidistra Flying, 1936).
In George Orwell’s (1903-1950) novel, Gordon Comstock leaves a successful career in advertising (‘the rattling of a stick inside a swill bucket’) to become a poet. But Comstock’s literary shortcomings push him slowly and inexorably into poverty, so the idealist and bitter writer pontificates about the materialism, dryness and mediocrity of the English middle class. And nothing could better symbolise society’s predictability and pedestrianism than the common aspidistra, aka bar room plant, iron plant or cast-iron plant (Aspidistra elatior). A native of Japan, the common aspidistra is widely cultivated as a houseplant around the world. Because of its sturdiness and tolerance to neglect, it became a favourite in English homes in Victorian times, although its popularity has since waned a bit.
W. F. Harvey (1885-1937), the Quaker author of macabre and horror stories, told the tale of Ferdinand Wilton, who tried unsuccessfully to destroy aspidistras, only to get some creepy just deserts… Image from Tatler magazine, 1930, British Library:
Orwell would be pleased to know that other characters could have embodied dullness and obscurity in Comstock’s social narrative: gnats.
‘Gnat’ is a loose term to refer to small (usually less than 1 cm), unremarkable and poorly known flies in the suborder Nematocera, which include crane flies, mosquitoes, black flies, and midges. Gardeners will be familiar with one particular group: the dark-winged fungus gnats (family Sciaridae). These tiny black flies make a nuisance of themselves by flying erratically and in great numbers around potted plants, often finding their way to rubbish bins, kitchen drains, window panes, and fruit bowls. The adults feed on nectar or on nothing at all (they have very short lives), and the larvae eat mostly fungi or organic matter in damp soil – that’s why potted plants are ideal for them. Fungus gnats are largely harmless, but if their larvae became too abundant, they may start to feed on plants’ tender roots, damaging them or transmitting pathogens. Seedling ‘damping off’ is a sign of possible fungus gnat infestation. Predictably, if you search for ‘gnats’ in the internet, most pages will be focused on ‘how to get rid of’.
Fungus gnats may be an occasional headache in households, but these uninvited guests represent a minute portion of their fauna. Besides the 2,500 or so species of Sciaridae, there are more than 4,500 species in the family Mycetophilidae and numerous species from related groups. Most of these fungus gnats live in shady, damp spots under forest canopies, along water courses or wetlands – places offering ideal conditions for their larvae. These permanently moist environments may be great for gnats, but are not so good for most pollinating insects, who require warmer, drier habitats and open spaces. So plants in fungus gnat territory. such as Aspidistra spp., have to find alternatives.
Flowers of the common aspidistra are nothing to look at. Oddly shaped, fleshy and coloured with a purple-reddish hue, they emerge directly from the rhizome at ground level or are sometimes hidden underneath the litter. People may not even notice their potted aspidistra has bloomed. And no aroma wafts from this plant: only a faint musty odour that some people can’t even detect. Everything from this flower gives it a mushroom appearance, so it’s far from ideal to bees and butterflies. And there’s more to put off run-of-the-mill pollinators: to access the pollen, they have to squeeze by a large stigma (the female part of the flower) to reach the pollen-producing stamens tucked underneath; only the smallest insects can do it. You probably can see where this is going.
The common aspidistra and related species cannot self-fertilise, but their pollination mechanism remained a mystery for years. Slugs, snails, springtails and other ground-dwelling invertebrates have been suggested as potential pollen vectors, but none of these candidates were backed up by data. Enter Suetsugu & Sueyoshi (2018), who spent two years investigating the common aspidistra in Kuroshima Island, Japan, where this plant grows wild. Their efforts paid off: they recorded two species of fungus gnats covered in pollen leaving and landing on flowers, and observed the successful development of fruits in gnat-visited flowers. These observations suggest the puzzle has been resolved. The researchers proposed, reasonably, that Aspidistra have evolved flowers that look and smell like fungi, thus becoming irresistible to fungus-eating gnats.
Flies are considered the second most important group of insect pollinators after bees; house flies (Muscidae), blow flies (Calliphoridae), flesh flies (Sarcophagidae) and especially hover flies (Syrphidae) pollinate a range of crop and wild plants. Some flies are essential pollinators in high altitudes, where bees are scarce or absent. Fungus gnats are hardly thought as members of the pollinators club because they don’t seem to have what it takes: they are too small to carry a decent pollen load, their ‘hair’ (bristles) – an important pollen-carrying apparatus – are puny, and they are weak fliers. Yet, pollination by fungus gnats occurs in 20 genera of eight plant families over the world.
Fungus gnats and other small dipteran insects such as midges and drosophilid flies are diverse and abundant, but we know very little about most of them because they are difficult to identify and study in the field. Worse yet, many species are nocturnal, and the flowers they visit are inconspicuous. So just like the midge-pollinated cacao, the gnat-pollinated aspidistra suggests there are many discoveries to be made about these pesky little flies.
Today’s photos of Costa Rica come from reader Leo Glenn. His narrative is indented, and you can enlarge the photos by clicking on them:
Here are some photos from my recent trip to Costa Rica. We spent most of our time on the Pacific side in the northwest region, in Guanacaste Province. The Pacific side has more distinct dry and rainy seasons, in contrast with the Caribbean side, which receives considerably more rainfall year round. Although slightly smaller in land area than the U.S. state of West Virginia, Costa Rica boasts 32 national parks, over 50 wildlife refuges, and over a dozen forest and biological reserves. This creates tension, of course, between preservation efforts and ecotourism, which is the country’s largest source of income.
The view from a higher elevation, about 20 minutes from where we stayed.
The local beach, Playa Avellanas, was a short walk from our lodging via a boardwalk that traversed a mangrove swamp, comprised mostly of White Mangrove (Laguncularia racemosa). After an earthquake in 2012, the land along the coast rose one meter, which closed off the mouth of the river, causing the water in the mangrove swamp to stagnate and kill all of the trees (thus the many dead trees in the foreground). A restoration effort was undertaken to restore the area and replant the mangroves. It appears to have been largely successful, though it will be years before the new trees mature and the ecosystem returns to something close to its pre-earthquake state.
The shallow and drier areas of the swamp were populated by several crab species, including the Racer Mangrove Crab (Goniopsis pulchra).
The forested areas on the path to the beach were dotted with numerous small burrows, inhabited by Red Land Crabs (Gecarcinus quadratus), which would freeze when approached, before slowly slinking backwards into their holes.
A juvenile Atlantic Ghost Crab (Ocypode quadrata). They were lightning fast, and very hard to photograph.
Some Brown Pelicans (Pelecanus occidentalis), flying over the beach. There were quite a few more in the line. Apparently, a group of pelicans can be called a pod, a pouch, a scoop, a squadron, or, if fishing as a group, a fleet.
Although colorful butterflies were abundant, I lacked the skill, patience, and hardware to photograph them, unless, as in this instance, I got lucky when one happened to land in the swimming pool. We rescued it immediately, of course, and after a few minutes spent drying its wings, it took flight. Theona Checkerspot (Chlosyne theona).
I did manage one halfway decent photo of an Apricot Sulphur (Phoebis argante).
A Crested Caracara (Caracara plancus), described on Wikipedia as “a bold, opportunistic raptor, often seen walking around on the ground looking for food,” which is exactly what this one was doing.
A nest of Northern Warrior Wasps (Synoeca septentrionalis), in a tree outside our lodging. According to Wikipedia, “It is a swarm-founding wasp that is also eusocial, exhibiting complicated nest structure and defense mechanisms.” The nest was about 30 ft up in the tree, and without a telephoto lens (or a very long stepladder), this was the best photo I could get. Its high location in the tree was a comfort to us, being so close to our rental house. Though not a particularly aggressive species, they are reported to have a very painful sting.
Regular Mark Sturtevant is back with a batch of lovely arthropod photos. Mark’s captions are indented, and you can enlarge his pictures by clicking on them.
Here are more pictures of arthropods. Some are from area parks, and others are from my house here in Michigan.
First up is an Antlion larva, Brachynemurus abdominalis. One can find the conical pits that these little beasties make all over what I call the Magic Field. How they use their pit to ensnare passing insects is shown in this video. Although they are easily extracted with a spoon to be taken home for pictures, actually getting pictures was not that easy since they generally want to scuttle backwards in an attempt to bury themselves. Right now, I am keeping a few larvae in cups of sand and feeding them ants (which is always entertaining), with the aim of later photographing the pupal stage. Antlion pupae are interesting in that they are still ill-tempered and they bite:
I came upon this wasp-mimicking beetle (Necydalis mellita) along a woodland trail. That it is indeed a beetle is proven by its elytra, even though they are very short. I’ve seen these before but could never get a picture because they are alert and flighty (wasp mimics tend to be wasp mimics all the way). But this one allowed a few pictures. It belongs in the longhorn beetle family:
Next up is a Big Sand Tiger Beetle (Cicindela formosa). These lovely but very alert beetles are common around here in sandy areas. Some days, nothing will get you a picture of one, but on this rather cool and overcast day the task was pretty trivial. Tiger beetles used to be in their own family, but now they have been absorbed into the ground beetle family:
Another challenging beetle is shown next. This is a tumbling flower beetle, Mordella marginata. Tumbling flower beetles belong to their own rather obscure family, and they are normally found on flowers where they eat pollen. There, the least disturbance will cause them to live up to their name as they curl up and fall to the ground:
Next are two grasshoppers because I really like grasshoppers. The first is a ‘hopper nymph of uncertain identity, but it most resembles the Two-striped Grasshopper, Melanoplus bivittatus.
Over the previous summer, I made it a regular habit to scour the front porch in the morning to look for insects that were drawn in overnight by our porch light. Among the more common squatters were these very small Mayflies which I believe to be Callibaetus ferrugineus. First are two females. The close-up picture is focus-stacked with my super macro lens, as are all of the remaining pictures here. She looks pretty strange, as all Mayflies do, but get a load of the male in the next picture.
Here is a male. I still remember my astonishment seeing the first of these! The upward turret-shaped portion of their compound eyes are thought to be used to watch for females:
This set finishes with a couple spiders. First up is a Slender Crab Spider, Tibellus sp. These are shaped to stretch out along grass blades:
And finally, here is a Ground Crab Spider, Xysticus sp. The super macro lens lets me peer into a new world, but I wasn’t expecting that face to look back from it!:
