Giant Damselflies

[johnnyboy]

Following on from my previous post I thought I'd post some giant damselflies. The Giant Bannerwing, Polythore gigantea, I caught myself
in the Monteverde Cloud Forest in Costa Rica in 1987, wingspan about 100mm

The Giant Helicopter Damselfly (aka Forest Giants) Megaloprepus caerulatus pair, female 161mm wingspan, male 166mm wingspan as measured using digital callipers. These are quite large sizes, average is around 150mm plus but larger individuals tend to occur in particular areas, the Costa Rican specimens are generally larger than those from Panama for example.

The Mecistogaster linearis male is 136mm in overall body length.

While in Costa Rica I wasn't fortunate enough to see Megaloprepus in flight but one of my friends did and described it as mesmerising, they really do give the impression that their wings are rotating like a helicopter.

Giant Bannerwing Damselfly imgur.com/gallery/uVHm3Ro

Giant Helicopter Damselflies from Costa Rica imgur.com/gallery/IzjoFhp

Giant Narrow Winged Damselfly pair imgur.com/gallery/qHctCPF

Johnny

[Adam Cotton]

The link seems to be incorrect, I get an imgur error message.

I know what you mean about damselflies giving the impression that their wings are rotating like a helicopter, I noticed the strange flight in some of our local (not so big) species too.

Adam.

[johnnyboy]

Adam,

I've put images separately on IMGUR now, one for the Polythore gigantea and one for the Megaloprepus pair. I shall add the third one of the Mecistogaster soon.

Thanks

John

[trehopr1]

These giants amongst damsel flies have been aptly called "helicopter damselflies" for their hovering/maneuvering abilities.

I first saw the term coined in a book that the eminent entomologist Dan Janzen edited in the early 1990's. It's title is Costa Rican Natural History.

In the book Dan mentions how these damselflies are specialist predators of orb weaving spiders (and the like). They hover in place right in front of the web and spider and "deftly" snatch the spider right out of the web; then carry it off and feed on it.

I imagine the spiders must be of a certain proportionate size for them to carry them off (not to bulking or big) but, it is truly fascinating behavior indeed !

A nice thread and I too happen to have a few select examples of these wonderful creatures.

Thanks for also sharing your pictures with us.

[Adam Cotton]

Do you mean Dan Janzen?
See:
en.wikipedia.org/wiki/Daniel_H._Janzen

Adam.

[johnnyboy]

I have the book, Costa Rican Natural History, too. I bought it before I visited Central America. Excellent book. Latin American Insects and Entomology, by Charles L. Hogue, is another great reference work.

Johnny

[trehopr1]

Yes, Adam that is him.

That was a "typo" oversight on my part while dictating my post over my phone.