Javier Abalos
@abalosaurus.bsky.social
300 followers 830 following 75 posts
I cannot be reborn as a velociraptor, but I can study lizard behaviour and coloration. Close enough.
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abalosaurus.bsky.social
🧪 New paper out! Growing up, wall lizards undergo a UV-visible “awkward phase” (who doesn’t?) that we can’t see—but they can. These ontogenetic color changes may mediate juvenile–adult interactions by delaying the onset of adult social signals. doi.org/10.1002/jez.... #colsci #lizard #ontogeny
Cryptic Ontogenetic Changes in the Ventral Coloration of a Color Polymorphic Wall Lizard (Podarcis muralis)
Wall lizards' ventral coloration undergoes cryptic ontogenetic color changes invisible without UV vision. We tracked wall lizards from hatching to one year of age. Spectrophotometry and visual modeli...
doi.org
Reposted by Javier Abalos
jakob-woodall.bsky.social
Round 4 of surveys for the Mt Lyell #salamander (Hydromantes platycephalus). We were able to sample 7 salamanders this time, including a juvenile! #herpetology #herps #amphibians
Reposted by Javier Abalos
wlallen.bsky.social
📢🦋 Our paper ‘Global selection on insect antipredator coloration’ is out and featured on the cover of @science.org

We ran a huge experiment to find out how ecological context favours camouflage and warning colouration as antipredator strategies. 1/6

www.science.org/doi/10.1126/...
A white-fronted bee-eater (Merops bullockoides) decides whether to consume a warningly colored white-barred acraea butterfly (Telchinia encedon). Photo (c) Mike Rowe
abalosaurus.bsky.social
Many wall lizards briefly sport bright blue tails as predator decoys after hatching. Our new study shows their throats and bellies also change color, yet at wavelengths invisible to humans! Could other species, too, undergo such cryptic shifts?
@uv.es @ucciuv.bsky.social
tinyurl.com/4rjfmde9
🧪🦎
Reposted by Javier Abalos
royalsocietypublishing.org
Watch #BiologyLetters author Avery Maune talk about new research revealing that urbanization can reshape social behaviour in the common wall lizard (Podarcis muralis): cassyni.com/events/3Hp2U... #AnimalBehaviour #ethology
Reposted by Javier Abalos
chikichanka.bsky.social
ESTO ES IMPORTANTÍSIMO
Euskadi suspende la campaña de la pesca de la angula ante la situación crítica de la especie
Un paso crucial para lo conservación de la anguila, tomada en el territorio donde su consumo tiene más arraigo
@miteco.gob.es y otras CCAA, os toca
www.europapress.es/euskadi/noti...
Gobierno Vasco suspende la campaña de la pesca de la angula de 2025-2026 ante la situación "crítica" de la especie
El Departamento de Alimentación, Desarrollo Rural, Agricultura y Pesca del Gobierno Vasco se ha reunido...
www.europapress.es
Reposted by Javier Abalos
methodsinecoevol.bsky.social
📖Published📖

Roemer et al. propose a comprehensive evaluation of the limits and possibilities of passive acoustic monitoring of bats, identifying knowledge gaps and practice barriers, and highlighting novel ideas that may revolutionise practices🦇👇

buff.ly/l8DGN7X

🌍 🧪
Influence of weather conditions, prey size and abundance, flight height and dialects on population trends, habitat selection and the spatial distribution inferred from bat acoustic activity obtained with passive acoustic monitoring. The dashed arrows represent possible biases that should be investigated in the future.
Reposted by Javier Abalos
pablomaciastorres.bsky.social
After a lot of time spent in the darkness of the wind tunnel, the results finally see the light.
I'm very excited to share what will become the first chapter of my thesis.
Energy conversion efficiency peaks at intermediate flight speed in a migratory songbird www.cell.com/current-biol...
Energy conversion efficiency peaks at intermediate flight speed in a migratory songbird
Using in vivo measurements of thrush nightingales flying in a wind tunnel, Macias-Torres et al. show that energy conversion efficiency varies with airspeed following a concave function, with a maximum...
www.cell.com
abalosaurus.bsky.social
Our discovery reveals a hidden stage in lacertid colour development that reshapes how we understand animal coloration as a signal, reminding us how central development is in communication and sexual selection across nature.
A young Podarcis muralis lizard doubts before crossing a crevice using a grass blade as a bridge. The first of many challenges he will face growing up!
abalosaurus.bsky.social
These colour changes may let juveniles avoid costly aggression or courting from adult males, while sparing adults wasted effort on non-competitors/immature mates. As lizards grow, greater colour differentiation may aid recognition and help stabilize social networks.
Adult Podarcis muralis lizards rest on top a log during a mesocosm experiment.
abalosaurus.bsky.social
Could these changes be adaptive? Predation avoidance often explains juvenile colour shifts, but in P. muralis that’s unlikely. Instead, a social role seems more plausible: ventral colour is usually hidden, yet adults display throats & flanks in social encounters
Adult males of Lilford's wall lizard (Podarcis lilfordi) from the island of Aire, close to Menorca. Two males are facing each other on yop if a log while adopting a raised-body posture that exposes the UV-reflecting spots and acts as a threat behavioral display.
abalosaurus.bsky.social
By the end of their first year, most juveniles show adult-like ventral colours. But only some, mostly males, develop UV-blue spots on their flanks, and these look still very different from adult ones to conspecifics.
Ontogenetic changes in Podarcis muralis throat coloration. (A) Pie charts represent the proportions of juveniles showing different throat colors (UV+w = UV+white, UV−w = UV−white, oo = orange, yy = yellow, ow = orange–white, yo = yellow–orange) in September (t1; 3–4 weeks after hatching), and June–July (t2; 1 year after hatching). The three pie charts correspond to the full data set of 417 hatchlings measured at t1 (purple), the subset of 66 surviving juveniles measured as hatchlings at t1 (green), and these same juveniles measured as yearlings in t2 (yellow). (B) Reflectance spectra from the 62 surviving yearlings showing pure color morphs (solid lines and shaded area represent means ± SEM). The dashed purple line represents the average throat spectra of 417 hatchling lizards (similar to that of the 62 surviving yearlings when first measured, see central pie chart). Spectra have been normalized by subtracting the minimum reflectance of each spectrum at all wavelengths. (C) Mean and CI95 of the chromatic and achromatic distances (dS and dL respectively) between paired measurements of throat reflectance (i.e., within-individual hatchling-yearling contrasts), separated by yearling throat color. JND stands for “Just Noticeable Differences”. Two dashed lines at 1 and 3 JNDs represent two theoretical discriminability thresholds. If the confidence interval of a point includes a discriminability threshold, the two colors are not distinguishable at this threshold according to receiver cone sensitivities and relative abundance.
abalosaurus.bsky.social
We found:

🦎 Hatchlings look white to us, but reflect far more UV than adults.

🦎 This “UV+white” is distinct and visible to lizards.

🦎 Ventral colours and UV flank spots develop out of sync.

🦎 Males and females diverge in timing and pattern.
Ontogeny of ventral coloration in Podarcis muralis. (A) Representative photographs of ventral coloration in a hatchling lizard 2–3 weeks after hatching (left), and in four yearlings re-captured in March 2019 (7 months after hatching). SVL stands for snout to vent length in mm. (B) Young male of P. muralis showing incipient UV-blue and melanin-based black patches in the outer ventral scales (OVS). (C) UV photograph of a hatchling P. muralis lizard showing UV+white color in its ventral surface. (D) Paired UV and visible photographs of the same subadult female (< 1 year) showing UV−white in the throat and UV+white in the belly. The difference is only apparent in the UV image. Photographs in C and D were obtained with a full-spectrum camera and two filters, each transmitting light either in the visible (400–700 nm) or the near-UV (320–380 nm) range. Brighter areas in the UV image have higher UV reflectance (i.e., hatchling ventral surface and female belly).
abalosaurus.bsky.social
In our “new” study (it’s from 2018, research goes slowly…), we tracked wall lizards from hatching to one year of age. We reared them in semi-natural conditions, measured their colours using spectrophotometry, and modeled how other lizards perceive them.
Juvenile common wall lizard hatching from the egg.
abalosaurus.bsky.social
Wall lizards (Podarcis if you're feeling fancy) are famed for dazzling color diversity matched by a UV-sensitive vision system. The widespread P. muralis shows ventral & lateral colors—including UV-reflecting spots and alternative throat colors— which likely play a role in social communication
Coloration in common wall lizard (Podarcis muralis). a) Alternative throat colours in males and females. b) Detail of UV-reflecting spots in the outer ventral scales. Extracted from Abalos et al., 2020 (https://doi.org/10.1002/ece3.6659)
abalosaurus.bsky.social
Spectrophotometry shows that UV colours are widespread in nature, and visual models can help to reveal its meaning. UV often acts as a private communication channel invisible to many animals. Flowers may seem flamboyant to us, but their colours are tuned to dazzle bees.
Left, conventional photography of a flower. Right, photography of the same flower obtained with a full spectrum camera equipped with a filter that only transmits light in the UV waveband. Brighter (yellow) areas show higher UV reflectance. Animals with UV vision see a difference in coloration between the center of the flower and the petals that we can't see.
abalosaurus.bsky.social
Understanding the function and mechanisms of ontogenetic colour changes (OCC) is a central goal in ethology. A bit of a challenge, though. Researchers must follow individuals as they grow, and some changes may slip by entirely if they occur in wavelengths beyond human vision.
Contrast of a tiger against a green vegetation background when viewed by their typical prey (a; deers and other cervids) and to a human viewer (b). Extracted from Fennell et al., 2019 (https://doi.org/10.1098/rsif.2019.0183)
abalosaurus.bsky.social
Growing up is tough. The world juveniles face often looks very different from the one awaiting adults. Many animal species deal with these shifting challenges by changing colour. Think of wild boar piglets losing their striped pyjamas, or bright-fluffed chicks maturing into duller adult plumage.
Wild boar mother, showing a much duller coloration than her piglets, which show a striped brown and yellow pattern.
abalosaurus.bsky.social
🧪 New paper out! Growing up, wall lizards undergo a UV-visible “awkward phase” (who doesn’t?) that we can’t see—but they can. These ontogenetic color changes may mediate juvenile–adult interactions by delaying the onset of adult social signals. doi.org/10.1002/jez.... #colsci #lizard #ontogeny
Cryptic Ontogenetic Changes in the Ventral Coloration of a Color Polymorphic Wall Lizard (Podarcis muralis)
Wall lizards' ventral coloration undergoes cryptic ontogenetic color changes invisible without UV vision. We tracked wall lizards from hatching to one year of age. Spectrophotometry and visual modeli...
doi.org
abalosaurus.bsky.social
333 wolf packs in Spain, 12% increase from the previous census (>10y ago). Sadly, local governments are approving 20% culls (targeting adult mothers for extra damage, ofc). The official excuse: preventing food waste. I kid you not. #lobovivo #loboprotegido #wolf

elpais.com/clima-y-medi...
El nuevo censo del lobo detecta 333 manadas en España, un aumento de 36 que no garantiza su futuro
Lejos de los 500 grupos necesarios para que sea viable genéticamente, el ministerio asegura que la especie está en “estado desfavorable” y que no se debería estar cazando
elpais.com
Reposted by Javier Abalos
vancedberg.bsky.social
It's out! Read about how to combine advanced animal vision modelling and colour pattern analysis with comparative phylogenetic methods in arguably some of the most incredible critters in the ocean: doi.org/10.1111/1365....
Amazing work with amazing people! #colsci #micaToolbox #AnimalEcology
Diel activity correlates with colour pattern morphology of heterobranch sea slugs
The authors show that daytime activity fundamentally shapes the appearance of prey animals to potential predators and that colour pattern phenotypes likely associated with visual signalling are predo....
doi.org
abalosaurus.bsky.social
La osadía de llamar cobarde a un toro (un animal social y doméstico) por rehuir el maltrato en la plaza. Pobre Antonio, quiere que los toros pongan de su parte en su sangriento espectáculo amañado. La tauromaquia, como los gladiadores: mejor en el cine y los cuadros, donde nadie sufre @elpais.com