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- "Damselflies of Alberta: Flying Neon Toothpicks in the Grass" by John Acorn [book review]
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- Damselflies of Alberta: flying neon toothpicks in the grass
Larvae are aquatic, and have a long, thin body with gills on the posterior end. They are usually greenish or brown. Larvae have a large labium that can extend to catch prey. The labium is long and hinged, so it rests beneath the head and covers the mouthparts at rest. Final instar larvae can be distinguished by their prominent wing pads. Their gills are usually pale, and much longer than they are broad.
Their eyes are rather large, and their abdomen is covered in setae. It can be difficult to identify individual Enallagma species, as many bluets must be distinguished microscopically. Boreal bluets are especially similar to northern bluets Enallagma cyathigerum though they are not found in the same area.
Males of Enallagma species have unique terminal appendages, while females have unique mesostigmal plates, located behind and underneath the prothorax. Acorn, ; Anholt, et al. Boreal bluets are hemimetabolous. Adults typically emerge in the summer, when they mate and oviposit eggs in bodies of water, then die shortly after.
Egg hatching time is water temperature dependent, taking as few as 11 days at Typically, eggs laid in June hatch in July. There are 5 or 6 larval instars, larvae reach the later instars by October. As temperatures drop and winter approaches, the larvae overwinter. They resume activity in mid-April, and molt and emerge from the water as a teneral, a sexually-immature adult.
This stage lasts 4 days to several weeks, during which, tenerals fly and feeds constantly. Female tenerals take longer to develop since they have more mass to support in the developing ovaries. Typically one generation is produced each year, but some populations are semivoltine, and larvae overwinter twice. This is likely in colder regions, where larvae resume activity later in the season due to cold water temperatures and cannot complete development in time.
Acorn, ; Baker and Clifford, ; Beirinckx, et al. For boreal bluets, mating occurs during the summer, typically June to July, though in warmer regions it can begin as early as May and end as late as September.
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Males spend much of their time near the breeding site, at the margin of lakes or ponds, while females forage farther away while they mature batches of oocytes. When females are receptive, they return to the breeding site. Males grasp the females by the mesostigmal plate with their terminal appendages, and fly in tandem. The terminal appendages and mesostigmal plate of each species has unique characteristics, which prevents crossbreeding, as they would not be able to connect and fly in tandem.
In males, the genital opening and copulatory organs are separated in the abdomen. The male must transfer his sperm from the end of the abdomen to the seminal vesicle under the second abdominal segment. The female's abdomen must swing forward, with the end making contact with the second segment, where sperm transfer takes place. This is called the "wheel" position. Copulation lasts 23 minutes on average; males usually perch on vegetation and grasp the females.
Boreal bluets are polygynandrous, both males and females mate multiple times with different mates, though they likely mate no more than once a day. There has much discussion about the role of female coloration in mating. Pale tan or green females are easily identified, while blue females have been referred to as male mimics. One theory suggests by mimicking males, they avoid harassment from potential male mates.
However, this would likely be detrimental to their reproductive success, as males would not select them as mates. This does not seem to be the case, though, as males do mate with them, so they probably should not be considered mimics at all.
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It is uncertain what purpose the male-similar coloration serves. Oviposition usually occurs while the male and female are still flying in tandem, though sometimes females oviposit alone. After mating, the pair spends several minutes searching for an oviposition site, and then up to an hour laying eggs on the surface or underwater, eggs are typically laid on leaves or plant stems.olegbook.kovalev.com.ua/assets
"Damselflies of Alberta: Flying Neon Toothpicks in the Grass" by John Acorn [book review]
Each female has clutches of almost eggs. Females lay multiple batches, requiring time between each mating to mature their oocytes. While doing so, females leave the breeding site and go to areas farther from water where males are less abundant. Anholt, ; Glotzhober and McShaffrey, ; Rivard, et al. Boreal bluets provide provisioning in the eggs, and lay them in a suitable aquatic habitat.
Otherwise, adults provide no parental care. Rivard, et al. Development from egg to adulthood can take several months to almost two years in some populations. Adults live 4 days on average, though they can live as long as 17 days. Paulson, Adult flight and foraging activities tend to be severely impacted by strong winds and rain.
With large wings and small bodies, these weather conditions can cause difficulties. If bad weather is approaching, boreal bluets abandon their pond or lake and take cover in vegetation. They can likely detect the drop in temperature and the decrease in light intensity, though this may just mimic nightfall, so they return to their night roosts.
They are diurnal, spending the night in vegetation. Males and females forage differently. Females spend more time away from the body of water where they emerged, to avoid unwanted male attention while they mature a new batch of oocytes. They need more energy to develop oocytes, so they spend more time foraging. Males spend less time foraging, as they require less energy, and stay closer to the water. Males are non-territorial, and adults are solitary except when mating. Larvae are sit and wait predators, and are largely solitary. In some species, larvae can be very territorial, but this does not appear to be true for boreal bluets.
When necessary, they can use their gills to swim. Anholt, et al. Adults stay near the ponds and lakes where they emerge, though females are more likely to disperse farther than males. Vision is important for damselflies.
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Hours of Play:. Tell Us Where You Are:. Preview Your Review. Thank you. Your review has been submitted and will appear here shortly. Reviews Rated 5 out of 5 by Deanna from Great for identifying damselflies Great for entomology and identifying the different species of damselflies Date published: Extra Content.
Editorial Reviews " Acorn's species accounts are very enticingly spiced with an abundance of well-researched and sometimes quirky natural history notes, scientific facts, interesting quotes and anecdotes. Indeed, these features should make it a well-read, used and sought-after book for a wide audience, including both amateur and professional naturalists, as well as field biologists and scientists, but also just 'plain folks' with a general curiosity about the natural world. In addition, the six introductory chapters preceding the species accounts also nicely summarize the biology and ecology of these amazing creatures and give a good overview of the history of research on damselflies in Alberta.
Like the rest of the book, they are very well-documented and engagingly well-written by an obviously passionate entomologist who is also an acknowledged modern-day expert in scientific popular writing and communication. In summary, I believe many will find this book of interest.
Damselflies of Alberta: flying neon toothpicks in the grass
In nearly all respects, it is one of the best of its kind on the subject and should prove itself a very welcome addition to any nature enthusiast's library. It's pretty easy to watch a damselfly up close, especially if they're sunning themselves on a leaf or branch — they're not as skittish as dragonflies, I find. Like wildlife? So do we! Every second Wednesday the Gazette profiles a reasonably common wild creature in the St.
Albert region. Birds, beasts, bugs, fish … so long as it's alive and kicking, we'll feature it. Send your suggestions to kma stalbert. Catching one is not recommended unless you have a net. Wild St. Albert Like wildlife? Albert Gazette in He writes about Sturgeon County, education, the environment, agriculture, science and aboriginal affairs. He also contributes features, photographs and video.