On today’s show we learn about the Manapany Day Gecko, a critically endangered reptile native to Reunion Island, a French Department in the Indian Ocean, roughly 1000 miles east of the African coast.
For more information about Manapany Day Gecko conservation see the Association Nature Ocean Indien at https://natureoceanindien.org
Rough Transcript
Intro 00:05
Welcome to Bad at Goodbyes.
On today’s show we consider the Manapany Day Gecko.
Species Information 02:05
The Manapany Day Gecko is a critically endangered reptile native to Reunion Island, a French Department in the Indian Ocean, roughly 1000 miles east of the African coast.
Its scientific name is Phelsuma inexpectata and it was first described in 1966.
The Manapany Day Gecko is small for a day gecko, measuring just about 5 inches nose to tail, with about 3 inches of that being tail. Their body is flat and cylindrical with a smooth texture, covered in tiny non-overlapping scales. The ventral scales, the bottom-side, the belly, are generally a creamy white, yellowish color. While the lateral scales (that’s the sides), and their feet and legs are an olive greenish-tan. And the dorsal scales, topside, the back, and tail are primarily a bright, like green apple, green. The back and much of the tail are marked with reddish-brown spots, and the head and neck feature super colorful and intricate scale patterns.
These intricate scale pattern are unique to each individual though generally we see:
A light blueish or white coloring at the tip of the snout, and a very thin blue band above the mouth
Then a thick red stripe across the front of their nostrils that continues back past the eyes.
Above the nostrils, on the forehead, there’s a bright cyan blue arch.
Then farther up the forehead is another red horizontal band that connects in a t-shape to a longer red stripe that runs vertical down the neck and upper-back.
The top of the head and neck have these complex undulating vertical stripes that fade into green down the back. There’s that red center stripe, the green stripes on each side, bluish-white stripes on each side of those, then red and black stripes outside those. The patterns are beautiful and like I don’t know, kind of joyful, these are like candy-shop colors on this tiny smooth squiggly being.
The Manapany Day Gecko has four limbs with five digits each, each digit ending in a pad-like shape with lamellae on the underside; Lamellae is a thin structure of millions of microscopic hair-like forms made of beta-keratin which allows for remarkable adhesion, the gecko can climb and cling to vertical surfaces, leaves, trunks and even windows, walls, and upside-down on ceilings.
To understand how this works we have to get into some physics and molecular chemistry that is way outside of my expertise, but I will try to break this down. Gecko foot adhesion relies on what are called Van Der Waal forces, operating at the atomic level. This is, at least for me, um, wildly complicated but here goes a simplified version:
Everything is made of atoms. Atoms are made of a positively charged nucleus with negatively charged electrons swirling around it. The electrons are constantly randomly moving. And so for a tiny fraction of a second, more electrons might randomly end up on one side of an atom, creating a bit of magnetism – one side becomes a little negative, and the other side becomes a little positive. This is called a dipole.
This dipole can affect nearby atoms, its electromagnetic attraction and repulsion causing the electrons in that nearby atom to also shift, resulting in another dipole aligned in opposite polarity to the first. So these brief instances of tiny, tiny atomic level magnetic attraction.
So now let’s imagine this happening between the atoms on the gecko’s foot and the atoms on the surface it’s sticking to. These singular dipole to dipole magnetic forces are miniscule and weak, too weak to like hold anything up. But the gecko’s toe pads are covered in these millions of microscopic hairs. When the gecko places their foot down, these hairs in contact with the surface creates millions of dipoles, a kind of magnetic pull between a huge number of atoms simultaneously. The sheer quantity of these small attractions adds up to a strong total force, a force strong enough to hold up the gecko’s body weight.
And then to move, they “peel” their toe pads away from the surface, changing the angle of the microscopic hairs, reducing the points of contact between their foot and the surface, incrementally breaking the magnetic bonds, allowing them to lift their foot and like take another step.
So, it’s not like a sticky goo (that’s a chemical bond) or a suction cup (that’s air pressure). It’s about these millions of tiny, flexible points of contact, resulting in billions of atomic level, dipole to dipole, weak magnetic attractions, which together create a strong overall grip.
We live in a remarkable universe.
Okay back to our general overview of Manapany Day Gecko morphology, back to front: tail, hindlimbs, torso, forelimbs, neck and head. The head is wedge shaped, with two nostrils at the tip of the snout, for respiration and olfaction, um, smelling.
They have a wide mouth with small sharp teeth, and a long agile tongue. On the roof of the mouth is their Vomeronasal organ which is a kind of secondary scent sensing system. The gecko uses its tongue to pull in airborne or surface-borne particles and transfers them to the Vomeronasal organ to sense prey, predators and pheromonal social signals. They also use their tongue and mouth for vocalizations, communicating via chirps and clicks.
They have large black round protruding eyes, with round pupils adapted for daylight. They do not have eyelids. So instead of like blinking, their eyes are protected by a transparent membrane called a {BRILL-UH} brille. To keep the brille clean and moist, gecko regularly lick their eyes with their long agile tongues.
Behind the eyes, the gecko has two small oval ear openings, covered by a thin membrane of skin, not scales, which allows sound to reach their ear drum. A recent study also suggests that gecko have a secondary sound sensing system in their inner ear to detect low-frequency vibrations. So they can both hear airborne sound waves and also detect vibrations, like rumbles in the ground, frequencies below their airborne auditory range.
The Manapany Day Gecko is in part so named because it is diurnal, meaning it is most active during the day. It is ectothermic, cold-blooded, and uses sunlight to regulate its temperature. It’s often found basking on leaves, limbs and sometimes coastal rocks. It is primarily arboreal though, generally sticking to the palms, tall ferns, and coconut trees of its habitat.
The Manapany Day Gecko is omnivorous, preying on insect and other invertebrate, like ants, moths, crickets, and millipedes. They also eat sap, fruit, and nectar and pollen. They are vital pollinators in their habitat. Sipping nectar from flowers, collecting pollen on their snouts and sometimes successfully transferring that pollen when they sip at a different individual’s flowers.
In areas where their habitat has been encroached upon by human development, they have developed opportunistic foraging behaviors, observed eating domesticated fruit on plantations, and sugary processed foods like jam and soda.
Manapany Day Gecko are generally solitary outside of the breeding season and do not form long-term monogamous bonds. Females may mate with multiple males during a breeding season. Breeding season is roughly September to March, end of winter, through end of summer in the southern hemisphere.
Courtship behaviors have been observed, with males performing lateral head bobs and tail wiggling while cautiously moving towards females. If she is receptive, she might reciprocate with similar subtle movements. If she is not receptive she will lift her forelimbs and make threatening tongue flicks.
When a breeding pair matches, the male will hold the female by the neck and wrap his tail under hers to align their sex organs for copulation.
After fertilization the female will lay her eggs in communal nesting sites. So multiple females all sharing a single egg laying location. And the gecko have been observed reusing the same communal sites over multiple seasons. She lays a clutch of two eggs but will mate with different individuals and lay up to six clutches in a single breeding season. The eggs are sticky, and laying sites include the leaves and crevices of screwpine trees, fronds and trunks of {luh-TAN} latan palms and coconut trees, and fissures and cavities in coastal rocks surrounded by native vegetation.
The eggs incubate for 2-4 months and hatchlings are precocial, meaning they can move, feed, fend for themselves at birth; there is no parental care after hatching. The young reach sexual maturity in about two years and estimated Manapany Day Gecko lifespan is 8 to 10 years.
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In the dream,
Interspecies communication. Oh in the dream to learn the chirps and clicks and taste the pheromones and understand the dance. To commune across the chasm of beinghood, in the rich language of another. Active witness to the wisdom, and the dreams of distant kin.
In the dream.
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The Manapany Day Gecko is native to Reunion Island, a French Department in the Indian Ocean, about 1000 miles east of the African coast. Here, roughly 50 physically isolated small subpopulations are confined to a 7 mile long narrow coastal strip, on the southern edge of the island less than 300ft from the sea, near Manapany-Les-Bains and Saint-Joseph.
The region is referred to as “Le Sud Sauvage” (the Wild South), where {buh-salt} basalt cliffs, formed from ancient volcanic eruption, meet the Indian Ocean. The gecko inhabit the coastal greenery and dry-tolerant vegetation of these coastal cliffs, found on palms, fruit trees, screwpines and ferns.
The Manapany Day Gecko has also shown some adaptation to human-modified landscapes, observed within papaya and banana plantations, on fences and mailboxes and even on the walls and ceilings of people’s homes.
This is a tropical coastal bioregion, with a wet and dry season. The warm wet season is roughly December to April, with highs in the mid 80s F, and lows in the mid 70s with roughly 45 inches of rainfall. In the dry season, highs are in the mid 70s, lows are in the mid 60s and there is only about 15 inches of rain.
The Manapany Day Gecko shares its island home with:
Stag Beetle, Réunion Little Mastiff Bat, Golden Cane Palm, Daisy Tree, Sea Lettuce, Coconut Tree, Indian Mulberry, Passion Flower, Red Latan {luh-TAN}, Réunion Harrier, Réunion Grey White-eye, Tropical Almond, Governor’s Plum, Brazilian Peppertree, Mauritius Hemp, Beach Morning Glory, Mascarene Petrel, Fishtail Palm, Sea Grape, Butterfly Palm, Screwpine, Réunion Bulbul and many many more.
Human development resulting in habitat destruction and modification, is an historic and persistent threat. There is fossil evidence that suggests the Manapany Day Gecko once had a much larger population, farther spread around the west and south of the island. Today urban encroachment, agricultural infrastructure and tourism development has confined the species to its narrow restricted range on the southern coast.
Relatedly, human introduced invasive plants are outcompeting the native coastal vegetation upon which the Manapany relies, further reducing the gecko’s viable habitat.
Many human introduced invasive animal species now prey upon the day gecko, including Wolf Snake, birds like the Red-whiskered bulbul and the Common myna, mammals like the Black Rat, the House Mouse, and the Asian house shrew, and even insects like the venomous Huntsman spider, and the Yellow Crazy Ant which sprays acid that can injure adult gecko and kill juveniles; the ants also prey upon the gecko’s eggs.
Human induced climate change is a looming threat to the Manapany Day Gecko. Climate models suggest a roughly four degree fahrenheit rise in temperature, and a decrease in rainfall in their habitat by the end of the 21st century. Which will affect the availability of food and will impact the gecko reproductive success.
Fortunately there are conservation actions in place to help protect the Manapany Day Gecko. The species has local legal protection. And since 2012, habitat restoration efforts have been removing invasive shrubs and replanting native palms in two subpopulation habitats.
And since 2013 a community outreach program has been encouraging locals to avoid harming the gecko and their eggs, to avoid pesticide use, and through seedling distribution programs, new plantings, and maintenance of native vegetation, to use private gardens and public green spaces as informal gecko sanctuaries.
Nevertheless the Manapany Day Gecko has been considered critically endangered on the IUCN Red List since 2021 and their population is currently in decline.
A 2011 survey counted less than 5000 individuals and more recent estimates suggest that less than 1000 Manapany Day Gecko remain in the wild.
Citations 30:42
Information for today’s show on the Manapany Day Gecko was compiled from:
Amphibia-Reptilia 44, 2 (2023): 139-152. Choeur, Arthur, Johanna Clémencet, Matthieu Le Corre, Markus A. Roesch, and Mickaël Sanchez. “Intra-annual variations of microhabitat use and movements of a critically endangered arboreal day gecko endemic to Reunion Island: implications for conservation”. – https://doi.org/10.1163/15685381-bja10125
Bulletin de la Société mathématique de France. 126. 9-23. Deso, Grégory & Probst, Jean-Michel & Sanchez, Mickaël & Ineich, Ivan. (2008). “Phelsuma inexpectata Mertens, 1966 et Phelsuma borbonica Mertens, 1942 (Squamata : Gekkonidae) : deux geckos potentiellement pollinisateurs de l’île de La Réunion”. – https://www.researchgate.net/publication/262917641
Bulletin de la Société herpétologique de France v.132 (2009): 43-69. Sanchez, Mickaël, Jean-Michel Probst, and Grégory Deso. “Phelsuma inexpectata Mertens, 1966 (Squamata: Gekkonidae) sur l’île de La Réunion: écologie, répartition et menaces.” – https://www.researchgate.net/publication/293695437
Bulletin de la Société Herpétologique de France, v.185. 2024. Jérémie Souchet, Valentin Vaslet, Julien Ducros, Chloé Bernet, Markus A Roesch. “La fourmi envahissante Anoplolepis gracilipes, une menace pour le gecko endémique de l’île de La Réunion, Phelsuma inexpectata ? The invasive ant Anoplolepis gracilipes, a threat to Reunion Island’s endemic gecko, Phelsuma inexpectata?”. – https://dx.doi.org/10.48716/bullshf.185-6
Bulletin Phaethon, no.53 2021: 36-40. Porcel, Xavier & Deso, Grégory & Jean-Michel, Probst & Dubos, Nicolas. (2021). “Sympatrie entre le Gecko vert de Manapany Phelsuma inexpectata endémique de la Réunion et le Gecko vert poussière d’or P. laticauda introduits au Domaine du Café Grillé: peuvent-ils cohabiter?” – https://www.researchgate.net/publication/349126355
Cahiers scientifiques de l’océan Indien occidental 2, 2011: 13-28. Sanchez, Mickael & Jean-Michel, Probst. (2011). “Distribution and conservation status of the Manapany day gecko, Phelsuma inexpectata MERTENS, 1966, an endemic threatened reptile from Réunion Island (Squamata: Gekkonidae).” – https://api.core.ac.uk/oai/oai:ojs.www.cahiers-wio.org:article/12
Current Biology, Volume 34, Issue 21, 4908 - 4919.e3. Han, Dawei. Carr, Catherine E. “Auditory pathway for detection of vibration in the tokay gecko.” – http://doi.org/10.1016/j.cub.2024.09.016
Herpetological Review. 52. 859-860. Sanchez, Mickael & Joly, Isabelle & Cazanove, Grégory. (2021). “Phelsuma Inexpectata (Manapany Day Gecko). Predation.” – https://doi.org/10.48716/bullshf.186-8
The IUCN Red List of Threatened Species 2021: e.T17450049A17450059. Sanchez, M. 2021. “Phelsuma inexpectata.” – https://dx.doi.org/10.2305/IUCN.UK.2021-2.RLTS.T17450049A17450059.en
Journal of Tropical Ecology 29, no. 3 (2013): 251–54. Clémencet, Johanna, Cyril Aubert, Doriane Blottière, and Mickaël Sanchez. “Kleptoparasitism in the Endemic Gecko Phelsuma Inexpectata: Pollen Theft from Foraging Honeybees on Réunion.” – https://doi.org/10.1017/S0266467413000229
Molecular Biology Reports v.50, 5501–5507 (2023). Gomard, Y., Sanchez, M., Bonanno, A. et al. “Development and characterization of twenty microsatellite markers for Phelsuma inexpectata (Squamata: Gekkonidae), a critically endangered gecko endemic to Reunion Island.” – https://doi.org/10.1007/s11033-023-08426-0
Salamandra. 58, no.2: 116–122. Choeur, Arthur & Clémencet, Johanna & Corre, Matthieu & Sanchez, Mickael. (2022). “Evidence of seasonal reproduction, laying site fidelity, and oviposition synchronicity in the critically endangered endemic Manapany Day Gecko (Phelsuma inexpectata) from Reunion Island (western Indian Ocean).” – https://www.salamandra-journal.com/index.php/contents/2022-vol-58
Wikipedia – https://en.wikipedia.org/wiki/Réunion_Island_ornate_day_gecko
For more information about Manapany Day Gecko conservation see the Association Nature Ocean Indien at https://natureoceanindien.org
Music 32:57
Pledge 38:59
I honor the lifeforce of the Manapany Day Gecko. I will commit its name to my record. I am grateful to have shared time on our planet with this being. I lament the ways in which I and my species have harmed and diminished this species. I grieve.
And so, in the name of the Manapany Day Gecko I pledge to reduce my consumption. And my carbon footprint. And curb my wastefulness. I pledge to acknowledge and attempt to address the costs of my actions and inactions. And I pledge to resist the harm of plant and animal kin and their habitat, by individuals, corporations, and governments.
I forever pledge my song to the witness and memory of all life, to a broad celebration of biodiversity, and to the total liberation of all beings.
