offspring

Climate change and an iconic Florida bird

December 31, 2024 By EarthWise Leave a Comment

The Florida scrub-jay is a medium-sized bird native to Florida, known for its striking blue plumage and distinctive call. It is the only bird species that is entirely endemic to Florida, found mainly in the scrubby, sandy habitats of the central and southern part of the Sunshine State.

But extensive development, habitat fragmentation, and habitat degradation have caused the scrub-jay population to decline significantly over the past century.

Another threat facing the Florida scrub-jay is climate change. According to a new study by researchers from the Archbold Biological Station and the Cornell Lab of Ornithology, warmer winters driven by climate change are causing Florida scrub-jays to nest one week earlier than they did in 1981. This seemingly innocuous change has reduced the number of offspring raised annually by 25% since 1981.

The research team examined 37 years of data to assess the impacts of warming on reproductive efforts. From 1981 to 2018, the average winter temperature at Archbold Biological Station in Florida increased by 2.5 degrees Fahrenheit. Despite increases in the number of nests built and eggs laid over the longer breeding season, Florida scrub-jays are not producing more young.

The researchers hypothesize that warmer temperatures make the nests susceptible to predation by snakes for a longer period of the Florida spring than in the past. The findings, which were recently published in the journal Ornithology, suggest that climate change could dampen the success of conservation efforts for this threatened species.

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Long-term study reveals warming climates threaten Florida scrub-jay

Florida Scrub-Jay

Photo, posted October 15, 2018, courtesy of Judy Gallagher via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Hope for white rhinos

February 28, 2024 By EarthWise Leave a Comment

There are only two northern white rhinos left in the world, and both of them are female. The last male died in 2018. Northern white rhinos live to about 40 and one of the two remaining is 35 and the other 24. The clock is ticking for the species.

Recently, scientists with the BioRescue consortium successfully used in vitro fertilization to impregnate a southern white rhino. It was the world’s first IVF rhino pregnancy.

There is now some hope that IVF could be used to produce more northern white rhinos. For various medical reasons, neither of the remaining two female rhinos can serve as a surrogate mother. But there is a plan B.

For a number of years, BioRescue has been creating northern white rhino embryos with eggs from the remaining females and sperm that was collected from males before they died. There are now 30 northern white rhino embryos in cold storage, and they are continuing to produce more.

The recent success with the southern white rhino IVF provides hope that southern white rhino females can act as surrogate mothers with implanted northern white rhino embryos. The species are similar enough that it should work.

The plan is to select surrogates and implant them. This should happen this year. A rhino pregnancy lasts 16 months. If this is successful, there could be northern white rhino babies in two or three years. The scientists want the offspring to live with the surviving northern whites for years to learn the social behavior of its kind.

It is possible that these gentle, hulking creatures may get a new lease on life.

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Just two northern white rhinos are left on Earth. A new breakthrough offers hope

Photo, posted September 16, 2017, courtesy of San Diego Zoo Safari Park via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Not All Eggs In One Basket | Earth Wise

March 2, 2021 By EarthWise Leave a Comment

Sea turtles lay their eggs in burrows on sandy beaches. Many species lay their eggs on the exact same beach year after year. On average, sea turtles lay over 100 eggs in a nest and produce between 2 and 8 nests per season.

Animals that produce such large numbers of eggs have this reproductive strategy because so few survive to adulthood. Sea turtle eggs and hatchlings face numerous threats including powerful storms, poachers, marauding birds, and more. Estimates are that only one in thousand sea turtle eggs leads to an adult turtle.

A recent study by the University of South Florida looked at the reproductive strategy of loggerhead sea turtles nesting on Keewaydin Island off the southwestern Gulf coast of Florida. The researchers found that individual females lay numerous clutches of eggs in locations as much as six miles apart from each other to increase the chance that some of their offspring will survive.

As the saying goes, nesting loggerhead turtles don’t lay all their eggs in one basket. The researchers compare the turtles’ strategy to investing in a mutual fund. The female turtles divide their resources among many stocks rather than investing everything in a single stock.

During their 50-year lifetime, a single female loggerhead will produce over 4,000 eggs and scatter them at 40 different sites. This strategy helps reduce the risk of complete reproductive failure caused by hurricanes and thunderstorms that could wash out or flood all their clutches. The combination of unpredictable patterns of nests over time and space results in nearly two-thirds of loggerhead sea turtle hatchlings making it into the Gulf of Mexico. The species still faces significant challenges but it is doing its part to try to survive.

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Not all in one basket: Loggerhead sea turtles lay eggs in multiple locations to improve reproductive success

Photo, posted January 27, 2012, courtesy of Jeroen Looye via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Fighting Malaria With Gene-Drive Technology | Earth Wise

June 8, 2020 By EarthWise Leave a Comment

Malaria continues to be a major health hazard throughout the tropical and subtropical regions of the world. There were 228 million cases of malaria in 2018 and over 400,000 deaths.

Malaria is a mosquito-borne infectious disease spread by 40 of the world’s 3,500 mosquito species. So, efforts to control mosquito populations are the primary strategy to eradicate malaria.

A team led by Imperial College London has created a genetic modification that distorts the sex ratio of a population of Anopheles gambiae mosquitoes using “gene drive” technology. The modification works by using a DNA-cutting enzyme to destroy the X chromosome during the production of sperm, which leads to predominantly male offspring, since females require two X chromosomes. The modification is coupled to a gene drive to allow it to spread through a population in a very effective way. A gene drive is a genetic engineering technology that propagates a particular modification by assuring that a specific form of a gene (or allele) will be transmitted with far more than the natural 50% probability.

The result of this is that mosquitoes produce more male offspring, eventually leading to no females being born and a total collapse in the population. The mosquitoes studied are the main malaria vector in sub-Saharan Africa. The hope is that mosquitoes carrying a sex-distorter gene drive would be released in the future, spreading the male bias with local malaria-carrying populations and causing them to collapse. Only female mosquitoes bite and take blood meals. If the gene drive technology works in the field, it could be a game-changer in the fight to eliminate malaria.

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Malaria mosquitoes eliminated in lab by creating all-male populations

Photo, posted June 20, 2014, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.