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Invasive species provide powerful in situ experimental systems for studying evolution in response to selective pressures in novel habitats. While research has shown that phenotypic evolution can occur rapidly in nature, few examples exist of genomewide adaptation on short "ecological" timescales. Burmese pythons (Python molurus bivittatus) have become a successful and impactful invasive species in Florida over the last 30 years despite major freeze events that caused high python mortality. We sampled Florida Burmese pythons before and after a major freeze event in 2010 and found evidence for directional selection in genomic regions enriched for genes associated with thermosensation, behaviour and physiology. Several of these genes are linked to regenerative organ growth, an adaptive response that modulates organ size and function with feeding and fasting in pythons. Independent histological and functional genomic data sets provide additional layers of support for a contemporary shift in invasive Burmese python physiology. In the Florida population, a shift towards maintaining an active digestive system may be driven by the fitness benefits of maintaining higher metabolic rates and body temperature during freeze events. Our results suggest that a synergistic interaction between ecological and climatic selection pressures has driven adaptation in Florida Burmese pythons, demonstrating the often‐overlooked potential of rapid adaptation to influence the success of invasive species. [ABSTRACT FROM AUTHOR]

Invasive species represent a significant threat to global biodiversity and a substantial economic burden. Burmese pythons, giant constricting snakes native to Asia, now are found throughout much of southern Florida, including all of Everglades National Park (ENP). Pythons have increased dramatically in both abundance and geographic range since 2000 and consume a wide variety of mammals and birds. Here we report severe apparent declines in mammal populations that coincide temporally and spatially with the proliferation of pythons in ENP. Before 2000, mammals were encountered frequently during nocturnal road surveys within ENP. In contrast, road surveys totaling 56,971 km from 2003-2011 documented a 99.3% decrease in the frequency of raccoon observations, decreases of 98.9% and 87.5% for opossum and bobcat observations, respectively, and failed to detect rabbits. Road surveys also revealed that these species are more common in areas where pythons have been discovered only recently and are most abundant outside the python's current introduced range. These findings suggest that predation by pythons has resulted in dramatic declines in mammals within ENP and that introduced apex predators, such as giant constrictors, can exert significant top-down pressure on prey populations. Severe declines in easily observed and/or common mammals, such as raccoons and bobcats, bode poorly for species of conservation concern, which often are more difficult to sample and occur at lower densities. [ABSTRACT FROM AUTHOR]

We describe characteristics of a Python bivittatus (Burmese Python) nest from observations made from December 2008 through August 2009 in Everglades National Park, Homestead, FL. The nest hatched on 28 July with a 77% hatching success. The female lost 54% of her body weight while breeding, laying, and incubating eggs, and abandoned the nest 3 days before eggs began hatching. Egg-mass temperature was 26.29–31.41 °C (mean = 28.07 °C), and was more stable than the temperature in direct sun above the nest, which ranged from 20.81 °C to 45.70 °C (mean = 28.45 °C). Egg-mass temperature was likely buffered from extreme heat by adjacent vegetation, where the temperature ranged from 23.19 °C to 30.48 °C (mean = 27.05 °C) and from extreme cold by shivering thermogenesis. Of successful hatchlings, 9 were male and 8 were female. [ABSTRACT FROM AUTHOR]

We identified 25 species of birds representing nine avian Orders from remains in digestive tracts of 85 Burmese pythons (Python molurus bivittatus) collected in Everglades National Park, Florida, USA, from 2003 to 2008. Four species of birds identified in this study are of special concern in Florida and a fifth, the Wood Stork (Mycteria americana), is listed as federally endangered. This represents the first detailed analysis of the avian component of the diet of the introduced Burmese python, now established in Everglades National Park, Florida and highlights the potential for considerable negative impact of this invasive species on native bird populations. [ABSTRACT FROM AUTHOR]