Residual Fragments of Past Lives

Stacked image of live Psychodidae pupa. (R. Isaí Madriz)

Residual Fragments of Past Lives

(Patagonia’s Untold Stories)

Decaying fragments hang from the cavity’s roof as streaks of viscous dark red liquid meander down its sides.

The peculiar scent of extracellular digestion from fungal mycelia impregnates the stale air.

I force myself into the cramped cavity to further investigate. With only half of my body inside, I sit motionless, looking up, in awe. The sound of silence is overwhelming.

The bifurcating trunk bears equally tall galleries. Water percolates high above, saturating the substrate.

Insects feeding on decayed organic matter have turned the surface cellulose into a pulp. Partially digested body segments of forgotten generations provide vital nutrients for those in current development.

Under the dim light passing through the large crack, I observe predatory beetles moving across my body, in search of tender larvae inhabiting the collapsed fragments from above.

I cover most of the small aperture to the outside, trapping myself in darkness. As I breath shallowly to fit in the claustrophobic space, the sound of intermittent water droplets impacting my forehead break the silence.

Inches away, a secret is being unveiled before my eyes. A new species of fly inhabits the tree cavity. Their unknown anatomy and behavior is revealed for the first time through the green hue of my night vision goggles.

Mature larvae 3mm long move below the organic matter, consuming the moist pulp. Their body segments are decorated with exquisite intricate patterns. Rows of hairs arranged throughout their dorsal side help trap the moist substrate.

Psychodidae pupae breaking out of their larval skin (left & right). Mature larva (middle). (R. Isaí Madriz)

Predatory slugs and spiders patrol the vertical surface. Below, hidden by the soft mass on their backs, larvae use their posterior respiratory siphons to acquire vital oxygen from above.

Lethargy signals the initiation of metamorphosis.

Their heads soon become an empty shell as their organs retreat inside their thorax to rearrange one last time.

Respiratory horns slowly grow out their backs.

As the insects develop inside their pupal skin, they outgrow their old larval skin, splitting it down its sides.

Psychodidae pupa breaking out of larval skin (left) mature larva (right). (R. Isaí Madriz)

They slowly migrate to the surface, where they are most vulnerable. The thin layer of moist substrate on their backs is their only defense against predators. There, they remain face down until their metamorphosis is complete.

An individual is ready to emerge. The pupa slowly pushes itself out of the old larval skin. With its exposed head capsule and thorax, the emergence commences.

The skin splits down the middle, from its forehead down its back, tearing its face off. Its larval head capsule and front half of its thorax hang perpendicular to its body.

With controlled movements from its abdomen, it pushes itself free. Its legs spread for the first time.

It uses its tender limbs to pull its compressed abdomen from its old skin. It is a female. She hangs on to the vertical wall until her skin hardens. Her larval and pupal skins are now part of the cryptic biological memoir inscribed in the lugubrious facade.

Soon after her emergence, a male begins to court her. The pair quickly disappear into the dark gallery above.

Down below, through the crack in the bark, daylight beckons those curious enough to investigate.

With a short and sharp flight pattern, a female slowly migrates down towards the glare.

As she moves downward, the moist substrate becomes dry and brittle, a metaphor of what is to come in her life.

Near the entrance, residual fragments of past lives hang from abandoned spider webs.

The female reaches the gateway to the exterior, stopping at the divisory line between light and darkness. Her antennae are gently swayed by the soft breeze caressing the bark.

I can only wonder how she perceives the world outside. Is she aware of the exterior’s expanse? If she only knew hers is one of the few remaining old-growth trees in the area. Can she grasp the magnitude of the decision she is about to make?

At that very instant, she leaps onto a wind gust and leaves behind the only world she has ever known.


R. Isaí Madriz PhD. Photo Credit: Randall Scott/National Geographic

Dr. R. Isaí Madriz is an entomologist and zoologist with expertise in freshwater aquatic insects of Patagonia. As a Fulbright-National Geographic Digital Storytelling Fellow, he is telling the story of deglaciation of the Northern Patagonia Ice Field, focusing on its vanishing aquatic insect diversity through images and stories of exploration, science and human connections. He combines combine hiking, bikepacking and packrafting to transect unexplored areas and secluded fjords in search of some of the rarest insects on the planet. This low-carbon footprint approach utilizes renewable energy sources to capture never-before-seen footage of remote glacial outlets and hidden valleys of wild Patagonia. Madriz wis documenting the largely unknown endemic aquatic insect fauna of this vital region before Chile’s Aysén region’s biodiversity is transformed forever.

Follow Isaí Madriz on Instagram, Facebook or Twitter.

Equipment used for the expedition that lead to this story is courtesy of Fulbright, National Geographic, Iridium, Boo Bicycles, Kokatat, Seal Line, Osprey,TentsilePatagonia, Voltaic & Jax Outdoor Gear.



  1. Rob Pivar
    2:37 pm

    Very cool!! Great pictures.

  2. Nicole
    Aurora, Il
    December 12, 11:09 pm

    Love the fact all this took place inside a tree!! Your amazing stories keep getting better and better! Can’t wait to read more!

  3. Erik H Lokensgard
    United States
    December 11, 9:33 pm

    Wow again! And all inside a tree…

  4. Jairo Ernesto Zamora Camarena
    December 2, 1:49 pm

    Felicidades al Dr. Ruben Isai Madriz Villanueva un excelente trabajo científico de una investigación profunda pero sobre todo la forma fe redactar y describir lps sucesos permiten al lector transportarse a esos eventos y lugares que describe, imprimiendo un estilo único que vendría bien a la nueva forma de hacer documentales para Nationalgeografic en hora buena el descubrimiento que se esta aportando a la ciencia.

  5. Wileta Burch
    Palo Alto, Californis
    December 1, 10:45 pm

    Awesome!! Beautifully written and described. An experience come alive.

  6. Barbara
    Palo Alto
    November 30, 10:56 pm

    Beautifully descriptive and detailed. Your narratives are exemplary and the photos are stunningly beautiful. My students were captivated and asked lots of questions, so you continue to inspire, and to ignite curiosity and wonder.

    • R. Isai Madriz
      December 6, 8:50 am

      Thank you, Barbara, for sharing my story with your students. I would love to answer their questions. Please encourage them to write individually or as a class. There is a lot of new and unpublished information regarding the insects of this region of the world that I would love to share with young, aspiring entomologists.

  7. Stephanie Lindsay
    Los Angeles, CA
    November 30, 10:26 pm

    Coming from the perspective of a non-biologist your stories are inspiring me to view the life of insects in new ways. I am excited to see the story unfold and learn more about these little known insects. As with all your posts the photos and drone footage are beautiful.

  8. AKC
    California, USA
    November 30, 7:28 pm

    Fascinating, thanks for teaching us and what beautiful photos!

  9. Rebekah Reynolds
    United States
    November 29, 12:53 pm

    A great story told by a great storyteller! Thanks so much for sharing!!

  10. Carlos
    Plano, IL
    November 29, 4:37 am

    Gracias por compartir el mundo que hay ahi, gran narracion y wow!! con la fotografia

  11. Sonia
    November 28, 8:50 pm

    I really enjoy every story you’re a great historyteller because I can feel the silent at the cavity and watch every step of the progress in the larvae wow, now I’m waiting to read the new story and pics from the flys on growth.

  12. Manuel Cordero
    Puerto Rico
    November 28, 3:05 pm

    Wow! Amazing pictures. Estoy ancioso de ver las fotos del adulto. Excelente trabajo Isaí!

  13. Gunnar Mikalsen Kvifte
    November 28, 2:29 pm

    Love these stories – looking forward to seeing pictures of the adults!

  14. Ulysses Diaz
    Aurora IL
    November 28, 2:20 pm

    What an incredible adventure. Your writing and descriptions reveal a whole new universe unveiling in the womb of this tree! What incredible pictures and video. Thanks for sharing!!

  15. Lorena Lara Diaz
    November 28, 12:32 pm

    Excelente publicacion de su investigación,que solo podemos conocer a traves de sus entretenidos relatos.
    FELICITACIONES por sus logros y darnos la oportunidad de conocer nuevas especies de esos maravillosos lugares del fin del mundo.
    Saludos y esperando,sus proximas publicaciones!!!✨

  16. Lorena Lara Diaz
    November 28, 12:23 pm

    Excelente investigación y me encato su relato,muy interesante!!!!!
    Espero pronto saber y conocer de estas especies que solo tenemos oportunidad de conocer a traves de Ud y National Geografic.

  17. Victor Garcés
    Chicago IL
    November 28, 10:25 am

    And thus…You guide us through the unknown as if it were our own reality. Thank you and Congratulations. Great work.

  18. Socorro Luna y Andrade
    November 28, 9:35 am

    Excelente fotografía .

  19. Olivia
    November 28, 8:59 am

    Muy interesante tu investigación. Felicidades por tu gran trabajo de exploración que nos da conocimiento del comportamiento de estos insectos en la cadena biológica.

  20. Brittany Clark
    United States
    November 28, 8:51 am

    Amazing find! The beautiful old growth forests seem to provide very diverse microhabitats. Lovely images.

    Please do share any photos of the adults if you have them!

  21. Socorro Luna y Andrade
    México D . F .
    November 28, 8:46 am

    Gracias Isai por compartir y develar el suspenso biológico en que estaba a través de tus reportes .
    Tu trabajo de investigación biológica se conjunta con una deliciosa narrativa del comportamiento de estos maravillosos insectos localizados en remotas regiones para nosotros. Y sólo con trabajos como este hacen posible la comprensión de la trama de la vida. Felicidades Isai .

    • R. Isai Madriz
      December 6, 9:33 am

      Socorro, gracias por tu comentario. Me alegra saber que mi narrativa pueda transportate a estos maravillosos rincones del planeta.