INTERNACIONAL
Cómo el cambio climático afecta al reloj biológico de las ranas y pone en riesgo su supervivencia

Mientras los días de otoño disminuían, las ranas arborícolas grises de Ohio iniciaron la preparación invernal, guiadas por la duración de la luz solar y no por la caída de las temperaturas. Así lo indicó un estudio publicado en el Journal of Animal Ecology, que advirtió sobre los riesgos del cambio climático para especies que dependían del fotoperiodo como señal principal para ajustar su fisiología de cara al invierno.
El desajuste entre la duración del día y las temperaturas, en inviernos cada vez más cálidos, podría afectar gravemente la supervivencia de estos anfibios y otras especies que emplean estrategias similares.
El equipo de investigación, liderado por Troy C. Neptune, Diana C. Koester y Michael F. Benard de la Case Western Reserve University, en colaboración con el Cleveland Metroparks Zoo y el Holden Arboretum, realizó experimentos entre abril y noviembre de 2023 en la Estación de Investigación de Campo de la universidad, en Hunting Valley, Ohio.
Según el estudio, los científicos manipularon el fotoperiodo de huevos y juveniles de ranas arborícolas grises (Hyla versicolor), simulando días largos, medianos y cortos, mientras mantenían la temperatura ambiental constante. Los resultados evidenciaron que las ranas sometidas a fotoperiodos cortos —típicos del otoño— acumularon reservas de crioprotectores en el hígado de forma significativa.

Estas reservas, compuestas principalmente por glucógeno transformado luego en glicerol, permitieron a las ranas soportar la congelación durante el invierno. Los ejemplares expuestos a días cortos almacenaron hasta 13,8 veces más glucógeno que aquellos bajo fotoperiodos de inicio de temporada y 8,2 veces más que los sometidos a días de duración media. Además, el tamaño del hígado resultó entre 3,4 y 2,7 veces mayor respecto a los otros grupos.
El estudio determinó que el fotoperiodo, sin descenso de temperatura, desencadenó todos los cambios fisiológicos necesarios para la preparación invernal. Las ranas de días cortos presentaron una tolerancia superior al frío, reflejada en una disminución de 0,4℃ en su umbral térmico mínimo, aunque no surgieron diferencias en la tolerancia máxima al calor ni en la temperatura preferida.
Sin embargo, este proceso implicó un coste: las ranas preparadas para el invierno bajo fotoperiodos breves alcanzaron un menor tamaño al realizar la metamorfosis y mostraron una tasa de crecimiento reducida a largo plazo. Troy Neptune explicó: “Existió una reducción significativa en el crecimiento; no comieron tanto, y lo que consumieron lo destinaron al almacenamiento de glucógeno en el hígado en lugar de al crecimiento óseo o muscular”.
Estos hallazgos sugieren que, en un clima desincronizado respecto a los patrones históricos, las ranas podrían invertir energía en preparativos invernales innecesarios. Michael Benard, profesor y director del departamento de biología de la Case Western Reserve University, indicó que “esto significó que pudieron destinar recursos energéticos valiosos a la preparación para el invierno que en realidad no necesitaban”. Este fenómeno, definido como trampa ecológica, apareció cuando una señal ambiental históricamente fiable —la duración del día— dejó de coincidir con las condiciones reales, provocando respuestas perjudiciales para la especie.

El riesgo de caer en una trampa ecológica afectó también a otras especies de regiones templadas y árticas que dependían del fotoperiodo para regular su fisiología y comportamiento, según el estudio publicado en Journal of Animal Ecology.
La contaminación lumínica y la expansión de rangos geográficos, impulsadas por la actividad humana y el cambio climático, alteraron la percepción del fotoperiodo y agravaron el problema. Aunque no se registraron colapsos poblacionales en las ranas arborícolas grises, los investigadores advirtieron que las especies con áreas de distribución más restringidas podrían enfrentar consecuencias mucho más graves.
La investigación destacó la innovación metodológica derivada de la colaboración entre Case Western Reserve University, Cleveland Metroparks Zoo y Holden Arboretum. Los científicos emplearon cubiertas opacas en estanques al aire libre y sistemas de iluminación controlada en laboratorio para manipular el fotoperiodo.
Diana Koester, profesora adjunta en la universidad y curadora de investigación en el zoológico, señaló: “Este trabajo resultó un gran ejemplo de cómo nuestra colaboración única aprovechó nuestros recursos colectivos para ayudar a resolver algunos de los desafíos de conservación más apremiantes”.
El fenómeno observado en las ranas arborícolas grises podría anticipar los desafíos por venir para otras especies menos adaptables o con rangos geográficos reducidos. Para estos organismos, la incapacidad de ajustar su comportamiento y fisiología podría redundar en consecuencias mucho más severas, poniendo en riesgo su persistencia a largo plazo.
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INTERNACIONAL
US warns Iraq must act against Iran-backed militia attacks on American assets

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Iraq’s Prime Minister Mohammed Shia al-Sudani is facing mounting criticism for his government’s inability to stop pro-Iranian militias and the Islamic Republic of Iran from attacking American, French, Italian and Kurdish military personnel and facilities in Iraq.
On Saturday, the U.S. Embassy in Baghdad said that all U.S. citizens in Iraq should leave «immediately,» as «Iran-aligned terrorist militias have attacked the International Zone in central Baghdad on multiple occasions.»
The announcement came after a missile reportedly struck a helipad inside the U.S. Embassy in Baghdad early Saturday.
Speaking on background, a State Department spokesperson told Fox News Digital, «The United States strongly condemns attacks by Iran and Iran-backed terrorist militias against U.S. diplomatic personnel and facilities, civilian targets and energy infrastructure in Iraq, particularly in the Iraqi Kurdistan Region.»
US EMBASSY IN BAGHDAD TARGETED AS IRAN LAUNCHES ATTACKS DURING OPERATION EPIC FURY
A billboard featuring a photo of Ali Khamenei, Iran’s supreme leader who was killed in U.S. and Israeli airstrikes, is seen along a street in Baghdad on March 9, 2026. (Murtadha Al-Sudani/Anadolu via Getty Images)
The statement added, «As Secretary Rubio has said, the Iraqi government must take all possible measures to safeguard U.S. diplomatic personnel and facilities and ensure militia groups cannot use Iraqi territory to threaten the United States or the region. Doing so is in Iraq’s interest,» the spokesperson noted, «We retain a range of options to protect our interests. We do not preview sanctions or sanction actions.»
A Kurdish official, speaking on condition of anonymity, told Fox News Digital that the Iran-backed Popular Mobilization Forces (PMF) in Iraq «are paid and armed by the Iraqi government. They are on the Iraqi payroll. This is not the first time they have fired on the U.S., the Kurdistan Regional Government [KRG] and the energy sector. These PMF have brazenly attacked U.S. military bases.»
According to the official, «Many of these leaders [from the PMF] are part of al-Sudani’s government and his very coalition.»
In a statement to Fox News Digital on Sunday, an official for Iraq’s Embassy in Washington D.C. flatly denied the allegations against al-Sudani. «We would like to unequivocally confirm that the allegations claiming the Prime Minister granted a ‘green light’ to any armed group to target U.S. or Western interests are completely false. The Iraqi government has repeatedly emphasized its firm rejection of any attacks on diplomatic missions or foreign interests.»
The representative added, «The Prime Minister has also issued several statements condemning such acts, describing them as terrorist activities, and has directed the relevant authorities to pursue those responsible and bring them to justice.»
Al-Sudani raised eyebrows last week when he congratulated the Islamic Republic of Iran’s selection of its new Supreme Leader, Mojtaba Khamenei, the son of the assassinated second Supreme Leader of Iran, Ali Khamenei. «We express our confidence in the ability of the new leadership in the Islamic Republic of Iran to manage this sensitive stage, and continue to strengthen the unity of the Iranian people in facing the current challenges,» al-Sudani reportedly said.
When asked about the congratulatory statement to Khamenei, the Iraqi Embassy official said, «This action falls within the scope of standard diplomatic practices carried out by many countries, including several Gulf states. Iraq maintains diplomatic relations with neighboring countries, including Iran, while simultaneously ensuring balanced relations with all its regional and international partners.»
IRAN PROXIES WAGE WAR ON ISRAEL, THREATEN US INTERESTS AS IRAQ SLAMMED FOR NOT DISARMING THEM

A member of the Imam Ali Battalions, the armed wing of the Islamic Movement of Iraq — a member faction of the Popular Mobilization Forces (PMF) paramilitaries — holds up a picture depicting Iraqi PMF commander Abu Mahdi al-Muhandis (who was in a US drone strike in early 2020), as other group members gather with its flags during a rally to mark annual Quds (Jerusalem) Day commemorations in Baghdad on April 5, 2024. (Murtaj Lateef/AFP via Getty Images)
The intensified attacks on the international anti-jihadi coalition in Iraq’s autonomous Kurdistan region on Friday resulted in the death of a French soldier and injuries to six other people. According to France 24, the commanding officer, Colonel Francois-Xavier de la Chesnais, said the French soldier, Arnaud Frion, was murdered by an Iranian-designed Shahed lethal drone.
The Iraqi Kurdish news outlet Rudaw reported on Saturday that the «Kurdistan Region was targeted with seven explosive-laden drones early Saturday as Iran and its proxy forces in Iraq continue to target the U.S. consulate in Erbil and other military and civilian sites in the Region.» Rudaw said since the start of U.S. Operation Epic Fury the Kurdistan area has been targeted with over 300 drone and missile attacks, resulting in the killing of seven people and 35 injured.
The Kurdish official complained that al-Sudani’s «government is not serious about taking on militias because the militias are part of the government.» However, the official praised the U.S. «The Americans are going after them aggressively over the last week with attacks on their [PMF] positions.»

U.S. embassy personnel inspect damage caused by a bombing in Baghdad, Iraq, on Saturday, March 14, 2026. (Hadi Mizban/AP)
According to a Long War Journal report, «Airstrikes, likely conducted by the U.S. as part of the U.S.-Israeli operation against the Islamic Republic, have continued targeting Iran-backed Iraqi militias.» Neither the U.S. or Israel have not commented on reports that they are striking the PMF.
Fox News Digital secured information in early March from the Israeli Defense Forces that drones have bee fired at Israel from Iraqi territory since the start of the war.
The PMF told the Iraqi News Agency that American military forces have conducted 32 airstrikes against PMF headquarters since February 28.
The Kurdish official urged the Trump administration to «demand that Iraq’s government stop paying and arming the PMF and target their banking system that finances the PMF.» The official continued, «We have shared information with the Iraqis and the Americans, who have in turn shared information with the Iraqi government.» On the terrorist activities of the PMF the official said, «The al-Sudani government has been unwilling to confront them.»
TRUMP THREATENS TO END IRAQ SUPPORT OVER AL-MALIKI COMEBACK BID TIED TO IRAN INFLUENCE

Supporters gather in Baghdad’s Sadr district holding Iranian flags and posters of Ayatollah Ali Khamenei following the announcement that he was killed in U.S.-Israeli attacks, on March 1, 2026 (Murtadha Al-Sudani/Anadolu via Getty Images)
The official bemoaned that the al-Sudani government initiated a «handful of arrests last year, and they were released on bail and were able to flee to Iran.» The Kurdish official said the KRG «provided the information to the Iraqi government about the perpetrators» who fled to the Islamic Republic.
An Iraqi official dismissed the reports on PMF terrorists, stating,» I have not heard of such a thing. I guess that’s not true.»
The Kurdish official cited two PMF groups as the most bellicose toward the U.S.: Asaib Ahl al Haq (League of the Righteous) and Kataib Hezbollah. The Trump administration sanctioned Asaib Ahl al Haq in March 2024. The State Department said Asaib Ahl al Haq «and its leaders are violent proxies of the Islamic Republic of Iran» and the group «is extensively funded and trained by Iran’s Islamic Revolutionary Guard Corps (IRGC) Qods Force.»
The U.S. government sanctioned Kataib Hezbollah in 2023. The Kurdish official also charged the al-Sudani’s government with imposing an embargo on imported goods to Iraqi Kurdistan as way «to strip away our autonomy and everything we can built over 30 years.» The autonomous Kurdish government is widely considered a robust pro-American ally.

Iran-backed shi’ite groups fighters celebrate on a street, after the IRGC attack on Israel, in Basra, Iraq, October 1, 2024. (Essam Al-sudani/Reuters)
The Iraqi official denied the embargo, stating, «The federal government does not pursue a policy of ‘embargo’ against the Kurdistan Region. The current measures aim to unify the legal, customs, and trade framework across all Iraqi borders in line with the federal constitution.
«No country can afford contradictory internal trade and customs regimes, as this risks harming the national economy as a whole. Our objective is a unified, fair economic framework that protects state revenues while respecting the region’s specificities, and we believe this is best achieved through dialogue and cooperation.»

Smoke rises from the U.S. embassy building in Baghdad, Iraq, Saturday, March 14, 2026. (Ali Jabar/ AP Photo)
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Entifadh Qanbar, a former spokesman for the deputy prime minister of Iraq, told Fox News Digital that «One could even describe the PMF as the Iraqi branch of the Iranian Revolutionary Guard, effectively functioning as an Iraqi Islamic Revolutionary Guard Corps. The PMF operates through a network of militias that frequently attack U.S. forces, foreign interests, and targets in Kurdistan.»
He argued for «The dismantling of the mother organization — the PMF itself. As long as the PMF exists, militias operating under its umbrella will continue to attack U.S. forces and regional targets.»
Fox News Digital reporter Greg Norman-Diamond contributed to this report.
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INTERNACIONAL
Dem candidate’s unearthed ‘winter Texan’ comment could haunt campaign

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Bobby Pulido, a Latin Grammy winner and music star, once said he would pursue Mexican citizenship and described himself as a «winter Texan» for spending much of the year south of the U.S. border, drawing scrutiny for his time spent internationally as he pursues a seat in Congress.
«It gets hot here, bro. Like real hot — like real hot. I’m a summer Mexican,» Pulido told interviewers in 2023.
«It sounds better: winter Texan. It sounds better to say, ‘I’m a winter Texan.’»
His comments, which Pulido says he made in jest, run counter to statements he made to NBC News earlier this month.
TEXAS BORDER DISTRICT DEM CUELLAR BEATS BACK PRIMARY CHALLENGERS
Bobby Pulido, Democratic Congressional candidate for Texas, speaks on Friday, Feb. 27, 2026. (Gabriel V. Cardenas/Bloomberg via Getty Images)
«I live in Texas. We’ve always lived in Texas. Since COVID, really — that’s just not true,» Pulido said, responding to accusations that he only sometimes lived in the district he is running to represent.
Pulido is best known for his Tejano and Mexican–Spanish folk-style songs, such as «Desvelado» and «Se Murió de Amor,» and has received five nominations for a Latin Grammy Award.
He won Best Tejano Album in 2022 and 2025.
Pulido’s career still takes him south of the border on a regular basis, leading him to tell local newspapers in Mexico that he was considering dual citizenship in 2015.
«I’m going to be Mexican because I want the same Mexican passport you have,» Pulido told El Norte, a Mexican outlet.
His last five concerts have been in Mexico, according to his tour website.
Pulido made headlines last fall when he announced a congressional bid in one of the country’s most competitive districts. Shortly afterward, he also drew scrutiny for a resurfaced history of posting links to explicit websites on his personal X account — as well as for a social media post of what appeared to be him urinating on President Donald Trump’s Hollywood Walk of Fame star.
TRUMP’S PARDON OF HOUSE DEM CUELLAR BACK IN THE SPOTLIGHT AS HIS BROTHER FACES INDICTMENT

Bobby Pulido, left, pictured alongside Trump’s Hollywood star, right. (Photo by Medios y Media/Getty Images; David Livingston/Getty Images )
He has also received backlash over his past vulgar attacks against Trump, including posting the Spanish translation of «f— your mother.»
«I’d like to give you the biggest ‘f— you» you piece of s—, a–hole, d— head, son of a b—-,» Pulido said to Trump in another post.
Despite those controversies, Pulido recently captured the Democratic nomination to run in Texas’ 15th Congressional District — a seat currently held by Rep. Monica De La Cruz, R-Texas.
De La Cruz, a two-term incumbent, needled Pulido over his time spent in Mexico through a post to X. She quipped that Pulido «only belongs at quinceañeras,» referring to the lavish, coming-of-age parties traditionally thrown for girls turning 15 in Latin cultures.
«Don’t threaten me with a good time,» Pulido shot back.
His campaign said Pulido asked local quinceañeras if he could attend them, drawing nearly 1,000 invites to parties in the district.
Pulido’s ties to Mexico extend beyond his music career.
A person familiar with Pulido’s background said his wife still lives in Mexico along with children from previous marriages. He also owns a house there and told interviewers in 2025 that he goes to Mexico for healthcare.
«We live on the border. My wife and I have a house in Mexico. So, we travel there, and we spend time over there. And I’ve had a pretty unique perspective of experiencing healthcare over there and healthcare here,» Pulido said.
TRUMP ENDORSES CUELLAR OPPONENT AFTER PARDONING DEM REP

Bobby Pulido holding his award at the Annual Latin Grammy Awards Premiere Ceremony on Nov. 13, 2025, in Las Vegas, Nevada. (Greg Doherty/Getty Images for The Latin Recording Academy)
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His campaign confirmed that Pulido does not have dual citizenship.
«Bobby has one citizenship — American, and he’s proud of it. And, frankly, there’s nothing wrong with people having ties to family and heritage across borders,» Pulido’s spokesperson told Fox News Digital.
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