While packrafting the southeastern edge of the Northern Patagonia Ice Field along Chile’s largest river, the Baker, in search of primitive crane flies, Anand Varma and I came across an exciting find.
In a fragmented location only accessible via water, among a lichened-covered forest, we discovered a single wing of the genus Neoderus adhered to the underside of a leaf, between the Northern and Southern Ice Fields. Yes, a single wing is a fantastic find when it comes to primitive crane flies.
Most likely you have never heard of them and that is because primitive crane flies are considered to be one of the rarest groups of flies in the world and only a handful of people have been able to collect them. With only one specimen ever collected in the late 1800s in the southern Chilean fjords, the genus Neoderus can be considered the rarest of all primitive crane flies.
During my last expedition in 2015 I secured four flies, the first and only specimens collected of this genus since its discovery.
stacked image of a Female neoderus sp. hanging on a Nothofagus sp. twig. Photo by R. Isaí MAdriz
With colder temperatures marking the last chance this year to find this rare group, I set off once again to complete what Anand and I started. I decided to target the locality where I found a lone wing two years prior. I loaded my backpack, took my hiking poles (or as my collaborators call them, “my gimpy sticks”, due to the frequency of my ankle injuries) and limped into one of the most pristine creeks I have seen. After a 1100ft climb and bushwhacking across dense forest I arrived to the location.
Upon arrival I removed my hiking boots and proceeded to relieve my ankle pain in the glacial creek. Soon after, I unpacked my 60+lb backpack and identified the perfect configuration for my tree tent, which was strategically located near the creek 6ft above the ground. Below my tent, I set up my “field laboratory” consisting of a stereomicroscope from the early 1980s with generic USB lights secured by duct tape and powered via rechargeable solar battery. This arrangement allows me to collect aquatic insects and immediately identify any promising specimen under high magnification. The dream camp set up of any insect-loving seven-year-old!
Not only does my tree tent provide a dry refuge from sudden rainfall, characteristic to this area, but it is also the perfect barrier from the numerous avian intestinal discharges I am constantly being bombarded with by territorial birds.
With sunset approaching, I decided to have something to eat. I packed all the necessary gear for this short expedition but managed to forget food.
Loose in one of my backpack’s hipbelt pockets, I found a handful of stale trail mix (from sometime since September) and a piece of chocolate.
Lack of aesthetically pleasing or “proper” camping food, seem to be a trend for this site. A couple of years ago, my food bag punctured and got wet while reaching this exact location, leaving me to consume lukewarm soft cheese, soggy bread and broken crackers accidentally blended into a paste-like consistency. Read more about this particular story here.
This time was no different. As I searched the creek looking for the unknown larvae of Neoderus and other aquatic insects, I intentionally separated the largest common stoneflies. I later proceeded to make my “back-country specialty” of au naturel stonefly and stale raisin kebabs on endemic southern beech twigs, complemented with all-you-can-drink glacial melts. A true delight! My other options were: 1) No food or 2) Soggy almonds and common black fly larvae, but the latter are quite slimy and a last resort among the edible insect choices on my list.
With hunger “satisfied”, I set up my blacklight a few feet away from the stream. While waiting for insects to be attracted to the light reflected on a white sheet, I set off into the dark forest in true nerd-like fashion with my rain pants synched up to my mid abdomen, my cuffs tucked into my socks and sporting my night vision goggles in search of nocturnal six-legged gems.
stacked image of a female Neoderus sp. resting on Nothofagus sp. twigs. Photo by R. Isaí MAdriz
Throughout the night, the UV light attracted all sorts of insects, including Darwin’s beetles, half-inch-long parasitic wasps, caddisflies, moths and many midges. Alas, no Primitive Crane Flies.
Soon after midnight, rain drove away most of the insects and continued to pour until mid-morning. With sunrise approaching and a sufficient few hours of sleep, I climbed out of bed, ate a forgotten stonefly still in the “food” container and the piece of chocolate for breakfast, put on my rain gear and limped across the forest in search of the insect I came for.
After wadding through the creek for a couple of hours with no success, I decided to direct my attention to the numerous fallen trees around the forest. Interestingly, a large decaying tree still hangs 8ft high over the creek. Underneath, a Neoderus female. After squealing like a piglet for some time, I proceeded to secure the specimen. Crane flies in general are well known among taxonomists to lose or detach their legs at will. This particular female had all six legs still attached, making it the only pristine specimen in the world.
With my precious find, I headed straight back to camp. Once there, I frantically packed it all up and awkwardly limped back to my vehicle a few miles away, all the while juggling the specimen, my heavy backpack and my “gimpy sticks”.
I drove eight hours back to my headquarters and proceeded to photograph the female. After a long and continuous photography session of 48hours the female finally died, but not before yielding the photographs above. These, along with one poor quality image from 2015, are the only photographs of a live Neoderus in existence. A true reminder of the biological jewels awaiting discovery in the vicinities of the Patagonia Ice Fields.
R. Isaí Madriz identifying aquatic insects in the field. PHOTO BY R. ISAÍ MADRIZ
*The Neoderus specimen in the photographs above belongs to a new species of primitive crane fly. A scientific (peer reviewed) publication is in process to formally describe this species.
Scraping sand grains and pebbles for nutrients, it has wandered the river bed for ten months. After hiding from predators under submerged rocks it is time to leave the safety of the river behind.
Primitive crane fly (A. gloriosus) collection site. PHOTO BY R. ISAÍ MADRIZ
Among the rarest species of insects in the world, Araucoderus gloriosus belongs to one of four primitive crane fly species found in South America. Is its rarity a result of what is happening?
Its instincts drive it in search of entangled root mats of marginal vegetation. For that, it must cross a hazardous field of exposed cobblestone. Its body is being pulled against the moist rocks. The unfamiliar sensation of gravity is sobering.
Devoid of legs, it pulls its heavy body forward with its mandibles.
Dawn enshrouds the river bank with a dense mantle of fog. There, not too far from the river’s edge, partially compressed between two fist-sized rocks, the putrid pupal remains of another of its kind is being consumed by scuttle fly larvae; an ominous sign of what lies ahead.
The chaotic arrangement of the rocks and the impoverished diatom film covering them, laid evidence of a violent recent flood, a humbling reminder of the power of the elements.
If it is to survive, the larva must hurry. The morning sun’s rays will soon dissipate the fog, exposing the migrating larva to predators.
It has begun. Hungry ground-dwelling birds scout the surface, while other small passerine birds circle above looking for an easy meal. Deadly parasitic wasps are in search of prey; their young will consume their host from the inside out.
The fourthmolt allowed the eyeless larva to develop light-metering primitive eyes, an elemental predatory avoidance tool.
Scanning Electron Micrograph of Primitive crane fly (A. gloriosus) larval head capsule. Photo by R. Isaí Madriz
Halfway from the marginal vegetation, it begins to burrow into the moist sand.
As I observe sitting motionless on top of a large rock I ask myself: Was the drastic behavior change triggered by the continuous sensation of morning rays? Is the larva aware of the constant danger from predators? Perhaps it senses imminent risk of desiccation.
As the day passes by I wait patiently. The night belongs to bizarre creatures. Found only in Patagonia, stoneflies over two inches in length are taking over the night. Emerging in mass, they invade the land in search of a safe place to complete their transformation to adulthood.
At last, the larva reached the entangled root mats of the marginal vegetation. It searches for a secure moist area to begin its transformation. Pupation is the most vulnerable stage in its life cycle.
Its larval skin has been shed. The thin and translucent pupal skin presents a unique view to its internal organs. Highly sensitive long hairs arranged in crucial areas of its body alert of changes in its surroundings.
Safe in the moist microhabitat, its clear skin darkens with the passing days. Within, its organs reorganize for the last time.
A few days pass by and the pupa’s skin is hardened, a promising indication of a successful metamorphosis
Primitive crane fly (A. gloriosus) pupa habitus ventral (left) and lateral (right)view. Illustration by R. Isaí Madriz
High above, recent snowfall failed to remain on the mountaintop. An unexpected flood engulfs the river bank, dislodging the pupa from its shelter. Trapped in the increasing current, the river gradient steepens, as whitewater fills the increasingly narrowing channel.
Unable to move its developing appendages, the pupa relies on buoyancy for survival. It must keep the two respiratory organs on its head above the water or it will drown.
Several hundred yards downstream, in a small foamy pool in the splash zone of a 20ft waterfall, a newly emerged adult male hangs on to the vertical side of a small rock, its discarded pupal skin floats among plant debris. With luck he will spread his wings for the first time.
Nearby, holding on to the exposed roots in the undercut riverbank, a female completes her metamorphosis. At the same time, hanging from the marginal vegetation, camouflaged by their exquisite coloration, males wait for receptive females to take flight.
The male at the base of the waterfall flies away in search of a warmer, drier place away from the cold mist. As I wade through the river, following the male’s path, I feel the soothing sensation of the sun warming my skin. The male’s adult body is being illuminated by the sun for the first time. Does he feel the same calming sensation as I do?
Its dull flight pattern and slow speed diversify, as the morning rays stimulate a graceful aerial dance revealed for the first time before my eyes. I stand motionless in the middle of the river, in awe. The exquisite wing pattern is complemented by an iridescent hue reflecting the sun’s rays. This fly is indeed glorious.
Stacked image of the Primitive crane fly (A. gloriosus) adult hanging from a Magellan’s beech (Nothofagus betuloides) branch. Photo by R. Isaí MadrizR. ISAÍ MADRIZ collecting A. gloriosus larvae. PHOTO BY Gregory R. Curler
In a blink of an eye the magic dissipates. The male is tackled out of the air and onto the overhanging vegetation by a dragonfly several times his size. The predator perches on a broad leaf a few feet away from where I stand. I watch in shock, as it slowly consumes the primitive crane fly, discarding the legs and wings as it gradually devours the thorax. Several thoughts run through my head: How does the fly process pain? Does he? What thoughts would be passing through the fly’s brain? Does he have any?
In the upcoming days little more is revealed of this species’ secretive adult behavior. The population size is a fraction compared to what it was two years prior. With adults becoming increasingly harder to find, their short adult life span and the ever-changing weather make the task at hand troublesome.
With the season passing, the adult population vanishes. It is cold, but the mountaintops have yet to retain any snowfall. Weather fluctuations turn what should be snow into rain, preventing accumulation of snow and consequently scouring the riverbed through the intensifying glacial melts that feed the river. Can this species survive the ongoing climatic challenges, or will it embrace the imminent fate of the bleeding glaciers that it fully depends on?
* The story above is an accurate assemblage of observed field events from 2013–2018 complemented by a scientific investigation on the species depicted.