Territorial song sparrows use increasingly threatening signals to ward off trespassing rivals. First an early warning that matches the intruder’s song, then wing waving – a bird’s version of “flipping the bird” – as the dispute heats up, and finally, if all other signals have failed, attack.
This hierarchical warning scheme, discovered by researchers at the University of Washington, adds nuance to a communication system that has been long-used as a model to study how people use and learn language (more…)
Discovery resulted from study of amphibians in ponds
The richer the assortment of amphibian species in a pond, the more protection that community of frogs, toads and salamanders has against a parasitic infection that can cause severe deformities, including the growth of extra legs.
The findings, published in a paper in this week’s issue of the journal Nature, support the idea that greater biodiversity in large-scale ecosystems, such as forests or grasslands, may also provide greater protection against diseases, including those that affect humans.
A larger number of mammal species in an area may curb cases of Lyme disease, while a larger number of bird species may slow the spread of West Nile virus. (more…)
Researchers from North Carolina State University have found that one of the most aggressive invasive ant species in the United States – the Argentine ant – appears to have met its match in the Asian needle ant. Specifically, the researchers have found that the Asian needle ant is successfully displacing Argentine ants in an urban environment, indicating that the Asian needle ant – with its venomous sting – may be the next invasive species to see a population boom.
In the world of invasive species, the Argentine ant (Linepithema humile) is a success story. Its aggressive, territorial behavior and ability to create huge “supercolonies” – consisting of thousands of queens and millions of workers – have enabled the Argentine ant to spread across the United States, displacing native species and changing ecosystems to suit its needs. No other ant species had been seen successfully pushing back – until now. (more…)
Scientists build new ‘tree of life’ for placentals, visualize common ancestor
Scientists have reconstructed the common ancestor of placental mammals–an extremely diverse group including animals ranging from rodents to whales to humans–using the world’s largest dataset of both genetic and physical traits. (more…)
Invasive species among marine science subjects in Cayman Islands study abroad program
With a spiky fringe of venomous barbs and bold brown-and-white stripes, the exotic lionfish invaded Florida waters several decades ago and expanded its range widely from the Caribbean to New York. Native to the Indo-Pacific, the invasive species has no natural predators in this part of the world and readily feasts on small fish and shrimp.
UD students have the opportunity to observe these intruders — up-close and underwater — in a new study abroad program offered in the Cayman Islands through the School of Marine Science and Policy (SMSP). (more…)
Like a self-absorbed teenager, insects spend a lot of time grooming.
In a study that delves into the mechanisms behind this common function, North Carolina State University researchers show that insect grooming – specifically, antennal cleaning – removes both environmental pollutants and chemicals produced by the insects themselves.(more…)
Decoded genome reveals secrets of pigeon traits and origins
Scientists have decoded the genetic blueprint of the rock pigeon, unlocking secrets about pigeons’ Middle East origins, feral pigeons’ kinship with escaped racing birds and how mutations give pigeons traits like feather head crests.
“Birds are a huge part of life on Earth, but we know surprisingly little about their genetics,” says Michael Shapiro, one of the study’s two principal authors and a biologist at the University of Utah. (more…)
The Stress Gradient Hypothesis holds that as stress increases in an ecosystem, mutually supportive interactions become more significant and negative interactions, such as competition, become less so. The idea has been hotly debated but is now backed by a review of hundreds of studies co-authored in Ecology Letters by Mark Bertness, professor of biology at Brown, who first formally proposed the hypothesis in 1994. The time has come, he said, to test its application and predictive value.(more…)
