In the effort to control the invasive Burmese python (Python bivittatus) scientists have discovered a potentially troubling development. Python hybrids between the Burmese and Indian python (Python molurus).
Python hybrids are a concern because the two species inhabit different habitats. The Burmese pythons are at home in the Everglades wetlands. Indian pythons tend to prefer drier land. The fear is that “intermarriage” could create pythons more adaptable to different habitats and ease the spread of the destructive snakes.
So far the number of python hybrids is not overly large. But there is some evidence Burmese pythons are already expanding their range. Anything that increases their ability to increase their range is unwelcome. The genetically mixed snakes were discovered during testing of 400 of the animals captured. It is assumed that the inbreeding occurred in Asia and is showing up in snakes hatched here.
The invasive pythons may have killed up to 90 percent of mammals in some parts of the Everglades. They are able to eat almost any animal around, including adult deer.
According to news reports in IFLscience:
“In 2018, researchers from the US Geological Survey carried out a genetic analysis of about 400 Burmese pythons captured across a wide area of South Florida. The study was published in the journal Ecology and Evolution.
At least 13 snakes were found to be a genetic blend of Burmese pythons and Indian pythons, indicating they were the production of hybridization.
“The snakes in South Florida are physically identifiable as Burmese pythons, but genetically, there seems to be a different, more complicated story,” Margaret Hunter, a USGS research geneticist and lead author, said in a statement.
Often when two similar species interbreed, their offspring are put at a disadvantage. They might be infertile or face other challenges that make them less suited to the environment. Sometimes, however, the right combination can create a hybrid that can outperform its non-hybrid counterparts. This is what’s known as heterosis, or hybrid vigor.
“[Interbreeding] can lead to hybrid vigor, that is, the best traits of two species are passed onto their offspring. Hybrid vigor can potentially lead to a better ability to adapt to environmental stressors and changes. In an invasive population like the Burmese pythons in South Florida, this could result in a broader or more rapid distribution,” explained Hunter.
Meanwhile, the battle against invasive pythons continues. Part of the reason why the python population has been so tricky to control is that the snakes are extremely well-camouflaged to the environment. While advances in genetic sampling won’t solve the issue alone, it is providing scientists with a new weapon to better understand the threat.
“Our ability to detect Burmese pythons in the Greater Everglades has been limited by their effective camouflage and secretive behavior,” added Kristen Hart, a USGS research ecologist and a co-author on the study.
“By using genetic tools and techniques and continuing to monitor their movement patterns, we have been able to gain a better understanding of their habitat preferences and resource use. The new information in this study will help scientists and wildlife managers better understand these invasive predators’ capacity to adapt to new environments.” (Links in original).
That the pythons seem to b expanding their range appears clear. How far they can go is still conjectural