From both the laboratory and the field test results, it is apparent that mosquito larvae are a favorite food source for the dragonfly nymph, a result that agrees with the laboratory-based observations of Hati and Ghosh (1965) in Calcutta.
Further work is necessary, however, to determine the proper methodology for the mass rearing and augmentative release of dragonfly nymphs that would make this biocontrol procedure feasible for widespread application.
66 *n = 3 FIGURE 1 Per-Dip Larval Density in Treated and Control Tanks Under Field Conditions in Kalna (10 Nymphs per Field Tank) Density of Larval Mosquitoes per Dip 15 days after 15 days after Before introduction introduction of removal of Type of Tank of dragonfly nymphs dragonfly nymphs dragonfly nymphs Treated 7.
mosquito) and Diplonychus indicus (water bug) have been considered as potential biocontrol agents against mosquitoes (Sankaralingam & Venkatesan, 1989; Steffan & Evenhuis, 1981), information on the predatory instinct of dragonfly nymphs with respect to mosquito larvae is rare (Fincke, Yanoviak, & Hanschu, 1997; Hati & Ghosh, 1965; Pritchard, 1964).
This fest will bring together experts in the field from around the state, other New England states, New Jersey and New York to share their information and help teach others how to better identify the various types of dragonfly nymphs
True, a person might find collecting dragonfly nymphs
and skins left behind from molting to scrutinize closely under a microscope a strange sort of hobby, but when local naturalists are brought together with scientists and experts from other parts of the country, an exchange of information and experiences occurs that widens the knowledge base of both.
While surveying, Ballengee also discovered a range of natural predators he suspected could be to blame, including stickleback fish, newts, diving beetles, water scorpions and predatory dragonfly nymphs
The Nature Boardwalk functions as a living laboratory in which to study these interactions, and researchers can be seen doing everything from setting up motion-triggered camera traps to counting dragonfly nymphs
Members of the trust's education team will help people spot pond creatures such as water scorpions, whirligigs and dragonfly nymphs
Ray Lockyer from Pontarda we, one of the attendees who is also one of the leading angling entomologists in Wales, said, "I was amazed at what was collected, the mayfly and dragonfly nymphs
were not isolated finds - there was a good number of both collected.
Whirlygig beetles and dragonfly nymphs
are just some of the insects you can identify.
To get a close look at dragonfly nymphs
, visit the Newport Wetlands open day next Sunday.
They emptied their nets full of tadpoles, fish, dragonfly nymphs
, pondskaters and beetles into observation jars while ticking them off on a list supplied by the rangers.