An indicator species is an organism whose presence, absence or abundance reflects a specific environmental condition. Indicator species can signal a change in the biological condition of a particular ecosystem, and thus may be used as a proxy to diagnose the health of an ecosystem. For example, plants or lichens sensitive to heavy metals or acids in precipitation may be indicators of air pollution. Indicator species can also reflect a unique set of environmental qualities or characteristics found in a specific place, such as a unique microclimate.
Above: Burrowing Mayfly, a clean water indicator species. Since they are very sensitive to pollution, their presence is indicative of clean water.
Since their introduction to the Atlantic Ocean in the 1980s, Pacific red lionfish (Pterois volitans) have gobbled up native Caribbean and western Atlantic reef fishes, reducing their abundance by up to 90%. Researchers think one of the secrets to the lionfish’s success is a predation strategy unheard of in other fish predators—blowing jets of water while approaching prey to disorient them. The squirting water (seen in the video) overwhelms the target’s lateral line, part of a fish’s nervous system that detects vibrations and warns of approaching objects, the team reports this week in Marine Ecology Progress Series. Prey often end up facing the hungry lionfish, increasing the chances of head-first strikes and lowering the risk of the lionfish getting stuck by backwards-facing spines.
You can watch a video of the phenomena by clicking the source (wouldn’t let me embed).
In a study led by Michigan State University (MSU) and the University of Guelph (Canada), researchers showed for the first time how females use social cues to correctly prepare their offspring for life outside the nest. The results, published in the current issue of Science, confirm that red squirrel mothers boosted stress hormone production during pregnancy, which increased the size and the chances of survival of their pups.
"Natural selection favors faster-growing offspring, and female red squirrels react accordingly to increase their pups’ chances of survival," said Ben Dantzer, formerly with MSU’s zoology department and now a postdoctoral researcher at the University of Cambridge (United Kingdom). "Surprisingly, squirrels could produce these faster growing offspring even though they didn’t have access to additional food resources."
Symbiosis is the close and often long-term interaction between two or more different biological species.
Above: In a symbiotic mutualistic relationship, the clownfish feeds on small invertebrates that otherwise have potential to harm the sea anemone, and the fecal matter from the clownfish provides nutrients to the sea anemone. The clownfish is additionally protected from predators by the anemone’s stinging cells, to which the clownfish is immune.
Studying the relationship between plants and the insects that feed on them is an arduous task, as it must be done through direct observation. It can take years for a researcher to fully understand the diets of a community of herbivorous insects in a tropical rain forest. Now, five Smithsonian scientists are paving a fast track using the DNA found inside the insects’ stomachs, potentially turning years of research into months. This method will help scientists understand the ecology and evolution of plant-herbivore interactions more efficiently.
The term “ecology” was coined by the German zoologist, Ernst Haeckel, in 1866 to describe the “economies” of living forms. The theoretical practice of ecology consists, by and large, of the construction of models of the interaction of living systems with their environment (including other living systems). These models are then tested in the laboratory and the field. (Field-work in ecology also consists of data collection that need not be inspired by any theory.)