Also, naturalists discover 60 new species of dragonfly and
damselfly in Africa, the National Institutes of Health reveals its first agency - wide strategic plan in more than 20 years, and the U.S. National Science Foundation plans a massive overhaul of its McMurdo research station in Antarctica.
Damselflies in the hotter setting displayed bigger differences in body size, higher activity levels and increased cannibalism rates.
Researchers have seen other species resort to parthenogenesis when isolated, such as
damselflies in the Azores.
Not exact matches
Better yet, on the dust - jacket of David Attenborough's splendid Life
in the Undergrowth, a creature that turns out to be a
damselfly appears to be sizing up the reader as it pauses, front legs arrested
in a judo - like stance, perhaps interrupted at tea.
Based on this effective model, the Dragonfly Monitoring Network was created with the aim of gaining a greater knowledge of the distribution and abundance of dragonfly and
damselfly species
in the Chicago region and, eventually, to expand the network across Illinois and beyond.
Dragonflies and
damselflies may mate while flying together
in mid air
in «tandem flights.»
Using
damselfly nymphs (Lestes congener) hatched
in the lab, researchers put nymphs of various sizes
in two different temperature environments, one a balmy 18 ° Celsius and the other a toastier 24 ° Celsius.
The researchers, who release their findings
in the Proceedings of the National Academy of Sciences, did not see a similar reduction
in trematode infections
in the presence of larval
damselflies, which are intraguild predators, meaning they attacked and killed not only the parasites but also the tadpole hosts.
Observations revealed that D. villosus took a far greater toll on the other species
in its tank than did G. duebeni, killing and mangling large numbers of blue - tailed
damselflies, water boatmen, fish leeches and water hoglice.
This implies that males, but not females, pay a high cost when they use color to communicate with other
damselflies, both
in terms of predation risk and visibility to prey.
In the new paper the researchers studied the conspicuous wing coloration of two species of
damselflies, which are predated by birds and prey on small flies.
We hypothesize that females use this to reduce male harassment, which is very intense
in damselflies.
Researchers from the Universities of Turku and Helsinki, Finland, are the first
in the world to discover which species adult dragonflies and
damselflies prey upon, as modern laboratory techniques enabled the study of the insects» diet.
The conspicuous wing coloration is used
in color communication between the sexes and between different species of
damselflies.
As a result, it is rare to find more than one larva
in a single tree hole, says
damselfly expert Viola Clausnitzer.
Damselflies live
in coastal forests that once formed a continuous belt
in east Africa but are now fragmented, forcing the creatures into small, vulnerable populations.
All the other giant
damselflies live
in South America.
When her team took a closer look at dragonfly and
damselfly antennae with an electron microscope, they spotted tiny bulbs
in pits that resembled olfactory sensilla.
Damselflies gravitated to the spot of the screen just on the other side of the fruit fly cluster, providing the first evidence that scents guide
damselfly and dragonfly behavior, the team reports this month
in the Journal of Insect Physiology.
Once believed to lack a sense of smell, dragonflies and
damselflies, such as Ischnura elegans (pictured), possess olfactory bulbs
in their antennae that may help them track prey.
Groups of cockroaches have consistently shy and bold members, whereas
damselflies have shown differences
in risk tolerance that stay the same from grubhood to adulthood.
Because dragonflies and their close cousins,
damselflies, don't possess glomeruli or any higher order smell centers
in their brains, most scientists believed these insects were unable to smell anything at all.
They used an experimental setup
in which a
damselfly was floated
in a glass vial and exposed visually and chemically to a fish predator.
404 Southeast aquatic species: The southeastern United States contains the richest freshwater biodiversity
in the nation, harboring 62 percent of the country's fish species (493 species), 91 percent of its mussels (269 species) and 48 percent of its dragonflies and
damselflies (241 species).
In the absence of mortality threat, growth rates of damselflies increased with warming until about 23.5 °C and then began to decline, a typical unimodal response to changes in temperatur
In the absence of mortality threat, growth rates of
damselflies increased with warming until about 23.5 °C and then began to decline, a typical unimodal response to changes
in temperatur
in temperature.