So what is a fly

You might be wondering how you can given the name "fly" to a flightless creature. Taxonomic groups reflect the evolutionary history of life. So for instance the great ape family contains orangutans, gorillas, humans and chimps because all these species descend from a shared common ancestor. When entomologists talk about "flies" they are referring to the taxonomic order Diptera - a group of insects that share a common ancestor that lived approximately 250 million years ago. Of course, organisms don't come with little tags telling us where they came from, it's the job of taxonomists to find characters that can be used to reconstruct that evolutionary history. The character that most sets flies apart from other branches of the insect tree of life is the presence of "halteres" - the stubby yellow structures  this predatory robber fly is modelling (more on that fly here).

Diptera means "two winged" and the name refers to the fact that most flies get about with one pair of wings, having reduced their second set into the flight-satablising halteres. This little innovation has allowed dipterans to become precision fliers, and one of the most successfully groups of organisms on earth with about 150 000 species (maybe 10% of all species are flies).

The true flies in order Diptera all descend from an ancestor which flew with two wings, but many of the species that descend from that ancestor have given up their wings. Because taxonomic groups are reflections of evolutionary history even wingless species are still flies - you can call them the apterous members of Diptera (wingless two-winged insects).

Flightless hippoboscids

Flies in the family Hippoboscidae are blood suckers. Many of these parasites fly from hosts to host, but a number of species have become so intimately associated that they've given up on flying - moving from one animal to another only while those hosts are in physical contact. The flightless hippboscids are generally called "louse flies" or "keds" and the most well known examples include species that specialise in drinking from pigeons, cattle and sheep. 

The "sheep ked" was once considered a pretty serious pest in New Zealand, but evidently it has been controlled thanks to "dip" and "pour on" insecticides that lambs are treated with. Besides the direct impacts, hippoboscids are potentiral vectors for blood borne disease, they have been implicated in the spread of avian malaria and are suspected for spreading other dieases. 

Bat flies, Bat flies, Bat flies

Bats seem to attract flies like... well they seem attract flies. At least three different lineages of flies have evolved a close relationship with bats. The largest group are, unsurpsingly, called "bat flies" (the taxonomy of this group is uncertain, but it includes the family Nycteribiidae). I have a soft-spot for most bugs, but even I have to admit bat flies are pretty gruesome looking creatures:

 Photo is CC 2.0 by Gilles San Martin

The bat flies have lost their eyes as well as their wings, by have made up for those loses in other body parts. The massive spider-like legs end in tiny claws that let the flies grip on the bat's fur and move about. Once stuck on a bat these flies drink blood.

 

Photo is CC 2.0 by Gilles San Martin

The fauna of New Zealand is very keen of flightlessness. Charasmatic mega-fauna like moa, kiwi and kakapo are the obvious examples, but we are also one of only two places on earth to have flightless perching birds (our three wrens are now extinct, as is the Canary Island Bunting). There are no truly flightless bats, but our short tailed bat is probably the closest thing - spending most of its time crawling around the forest floor. Our terrestrial bat hosts its own flightless flies. Apparenlty Mystacinobia zelandica descends from a blowfly but its association with the short talied bat has changed its body so greatly that is was not originally considered to be a fly at all, and thought to represent a unique order of insects. I couldn't find any photos of Mystacinobia avaliable with a permissive license, but check out the New Zealand Geographic story and Te Ara's article, which even has a video.

Mystacinobia has been placed in a family that is endemic to New Zealand, but there is one fly family with an even more restricted range. As far as we know, the family Mormotomyiidae is represented by a single species (Mormotomyia hirsuta) which is only known from a particular site in on one mountain in Kenya. As you may have guessed the site is a bat roost, and the animal, despite being only distantly related to the other bat flies discussed above, has taken on the spidery form that is associated with flies that spend their lives with bats.

 

Photo AFP

Mormotomyia doesn't have the hooks that other species use to cling on to bats, so it may be a little more free-living than than the species discussed above.

Phorids

The family Phoridae might be the strangest group of flies . Hell, one genus is made up entirely of flies that burrow into the heads of ants, decapitate them, and use the severed head as a cocoon.

Photo from USDA (public domain)

Those flies can fly, but there is a phorid species within an even stranger life history. Male Aenigmatias lubbockii looks like a prefectly normal, albeit tiny, fly:

 

The female is something all together different:

A.lubbockii is a parasitoid of ants, the females live within an ant nest and lay eggs in the ants pupae. It is though that the rounded body, with relatively few jointed segments for ants to hang on to, helps them move around within a nest. But, of course, for that to work females need to be able to move on from the nest in which they are born. That's where the winged male comes in, A. lubbockii males airlift their females into ant nests. The males pick up females and carry them, mating on the wing, before dropping them off to infiltrate a new nest.

So, so many more

Labels: fly, sci-blogs, science, sunday spinelessness

Last week I told you all that I had a great idea for a Sunday Spinelessness post, but not enough time write it. So, of course, this week I've managed my time in such a way... that there's still no way I'm going to get to write that idea up.

I'll leave that idea for another day, and, instead take inspiration from one of Alex Wild's recent posts at Myrmecos. The bug-blogo-sphere is filled with wonderful photographers, producing absolutely stunning portraits of the little creatures that run our world. When I go out fossicking for bugs, it's images like Alex's ants and Ted's beetles that I have in mind. That mindset inevitiably leads to dissapointment, since I'm restricted to a point an shoot camera. As much as I love my camera, it's never going to challenge dSLRs for image quality and its lens can't produce the sort of magnification a really good macro lens can. But, Alex points out, I shouldn't be disappointed that my camera can't do something it's not designed for, instead, I should take advantage of some of the things digicams really are good at. In partcular, the small lenses used in these cameras create a wide depth of focus, which can capture not just a bug, but a little of the the way the world looks form a bug's point of view. With this new idea in mind I went out today and... well, completely failed to get anything interesting. It was a grey sort of a morning here in Dunedin there wasn't much life out at about. Instead, here are a few older images that gel with Alex's tips:

First, a soldier beetle looking for food in masterwort flowers in the UBC Botanical Gardens in Vancouver. I tried, and failed, to get a close up of these beetle's face; but did get this one:

Flowers seem to be the over-arching theme in thse photos. A bumblebee visiting a dahlia (I probably should have thought a bit harder about the background here...):

I've taken a few decent photos of bumblebees, but I've never taken a good one of a honeybee. Or at least, I've never taken a good photo of a sinlge honey bee, I quite like this one with hundreds of bees flying in and out of their hives.

And finally, back to the dahlia for my favourite of these photos. A tiny fly, far too small for my camera to capture in any great detail, but looking pretty good in this setting:

Labels: bee, beetle, bumblebee, fly, photos, sci-blogs, sunday spinelessness

It's about time I stopped drip-feeding these Vanuatu photos and presented the "best of the rest".

I've had a very tough time trying to identify most of the bugs that I came across in Vanuatu - there aren't really any resources dedicated to invertebrates in Vanuatu or even Melanesia in general so it's a matter of trying to ID each creature as far down the taxonomic scale as possible then hope there is something recorded for that taxon in Vanuatu. Thankfully, I got a helping hand in idenfying this odd looking fly:

Ted MacRae encountered a similar looking fly in his travels through Brazil (and took a much better photo, you shold check it out) and he had the skill and the perserverance to work out his fly was from the family Neriidae (sometimes called cactus flies or stalk legged flies).

Evidently, the feature that seperates Neriids from realted families is the bristle like "arista" on the top of the antennae which is nice and clear in this photo. Neriid species from the genus Telostylinus have been recorded from New Caledonia (which is adjacent to Efate, the island on which were staying in Vanutatu) and the black and white stripes on this fly suggest its from this genus. If you look at Ted's photos, you can see the forelimbs of male Neriids are spiked, a feature you usually see in predators like crab spiders and robber flies which need to grab and hold their prey. Neriids eat rotting plant material, which is unlikely to escape their grip. It seems the spikes are used when males wrestle and strike each other in the hope of gaining access to females.

Here's the first invertebrate I saw after landing in Vanutatu:

You'd have to try very hard to miss these massive orb web spiders, in the fifteen minute drive from the airport to house at which we stayed I spotted five or six. In town, they tend to set up their webs on power lines and between houses. I gather they are Nephila plumipes, one of the golden silk orb weavers. Unfortunately, becuase they weave their webs at such great heights and I couldn't get close enough to them, these photos don't really show how massive these spiders are.

Female Nephilla are the largest of the web building spiders, their bodies alone are about 50 mm long and their webs span 2 metres. If you look closley at the photos above you'll see some much smaller spiders in the same web as the massive one. The smaller spiders could very well be 'kleoptoparasites', species that live within the webs of larger spiders and steal their host's prey. But, it's also quite possible some of the smaller spiders are males of N. plumipes, eyeing up the much larger female as a potential mate.

It seems the evolutionary process that made Nephilla females so large left the males of the genus behind. In fact, small males are probably less likely to mistaken for food by the large females, so it's even possible that males of these species got smaller at the same time as the females grew. Whatever the reason, Nephilla males are often ten times smaller than their mates. This is the bit where I would have tried to explain some of the mechanics of spider sex, but, rather wonderfully, Isabella Rosellini, has already done that:

Thanks to Alex Wild for finding that video, his post presenting includes a great photo of the difference between a male and a female Nephilla.

I think there's room for one more spider from Vanuatu as the last of terrestrial invertebrates from my trip. An unidentified orb weaver in the sun at the Mele Cascades waterfall:

Labels: diptera, environment and ecology, fly, nephilla, nerridae, photos, sci-blogs, spider, vanuatu