(Don’t Fear) The Hippoboscidae

I spent most of today with a fly. That may seem like a huge waste of time, but this was no ordinary fly – it was a wallaby fly. The closest I usually get to one of these flies is when I see a wallaby in the garden furiously flicking its ears trying to dislodge one. The individual here took a liking to me in the garden, and hitched a ride inside.

Flies of the family Hippoboscidae are all blood-sucking ectoparasites, i.e. parasites that live on the outside of their hosts. These flies usually cling to the hair of mammals or feathers of birds depending on the fly species involved. They have characteristically flattened bodies, powerful legs, and fishhook-like claws (clearly visible in the image below). You can see now why they are known generally as ‘louse flies’. There are more than 200 species found throughout the world (30 species here), and about 75% of them are ectoparasites of birds.

Wallaby Fly Hippoboscidae

Hippoboscid flies are quite particular about their hosts, for example flies which feed on mammals are not found on birds or vice versa. Back in the 1930’s research was conducted to determine if pigeon louse flies (Pseudolynchia canariensis) could bite humans and survive on human blood. The conclusion? They will bite humans when given no other choice of warm-blooded host. In other words, only when they are forced to. In case you were wondering – I wasn’t bitten.

Farmers in cooler regions of Australia may remember the introduced hippoboscid species Melophagus ovinus known as the ‘sheep ked’ or ‘sheep-tick’. In the past heavy infestations of this pest could cause anaemia in sheep, but modern farming practices have made occurrences of this pest quite rare. If you want to know more about this pest go here.

Green peach aphid giving birth to live young

While reading about hippoboscid flies I learned a new phrase – ‘adenotrophic viviparity’.  I was familiar with ‘ovoviviparity’, where eggs are held within females until they hatch internally, and the females give birth to live young. The picture above shows a green peach aphid doing just that. Adenotrophic viviparity is where eggs hatch inside the female, and the larvae are fed internally until they are mature enough to pupate. The larvae pupate immediately after being deposited by the female. The vulnerable larvae are therefore only momentarily exposed to predators.

I photographed the wallaby fly on the back of my hand in an attempt to show that it was a bloodsucker. It was also a skittish critter! Towards the end of the shoot it flew off my hand and landed on my black T-shirt – camouflaging it beautifully. It wasn’t until it crawled onto my face that I knew where it was. “Perhaps I’ve got enough photos now”, I thought. I hastily retrieved the fly and released it outside. Look out wallabies!

Footnote:
Many of you will have noticed that my post title (Don’t Fear) The Hippoboscidae references the 1976 Blue Oyster Cult classic (Don’t Fear) The Reaper. This song has had several lives including the original (link), the merciless Will Ferrell et al parody (link) – where the line ‘more cowbell’ originates – and the fun version with cowbell (link) by Leo Moracchioli.

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Historic weevil

I first published this story back in April 2015. Recently, I spoke about this weevil on ABC Radio Ballarat and also at a talk I gave to Friends of the Grampians Gariwerd (FOGG) so I thought now is a good time to republish.

I found this fellow trundling along the road when I went for my morning walk the other day. This insect is commonly known as a Botany Bay weevil (Chrysolopus spectabilis) or by its other common name “diamond weevil”. This is the male of the species. Females are larger insects, making males the lesser of two weevils (sorry, I couldn’t resist!).

Botany Bay weevilBotany Bay weevils belong to an historic group of insects. This weevil was collected by Sir Joseph Banks on Captain James Cook’s voyage to Australia in 1770. Actually we don’t know that Banks himself collected it – it could have been one of his men, or the Swedish naturalist Daniel Solander who accompanied Banks on the voyage. On his return, Banks gave the task of cataloguing his insect collection to the Danish insect taxonomist Johann Fabricius. The weevil was described in 1775, making it one of the first (if not the first) Australian insects described to western science.

Sydneysiders may be surprised to learn that the Botany Bay weevil is not only found around Sydney, but from coastal far north Queensland to eastern South Australia. The weevil is certainly common in New South Wales and its common name probably dates back to the early colonial days of Botany Bay.

To this day we don’t actually know where Banks’ specimen was collected. Was the weevil collected at Botany Bay in April 1770, or during July/August 1770 when Cook was repairing the Endeavour near present day Cooktown, or at one of the other landing points in between? The label on the specimen simply says “nova Hollandia”.

Botany bay weevil femaleBotany Bay weevils are associated with about 30 species of Acacia. Female weevils chew holes in stems at or below ground level in which they lay their eggs. Upon hatching the larvae bore into the stem and usually down into the roots. Adult weevils emerge in the summer, and what spectacular insects they are with their rich metallic green or blue markings on a black background. The adult weevils also feed on Acacia spp. in their characteristic manner of removing the leading shoots several centimetres down the stem.

The Botany Bay weevil has a distinctive defence mechanism. One day I was taking some close-up images of weevils on Acacia provincialis when I got just a bit too close for comfort. The weevil suddenly went stiff, toppled backwards and fell to the ground like an actor in a B grade Western movie. The trick I learned was to move closer to them slowly, taking photos as I went, so they got used to me and the noise of the camera.Share this:
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Cottony scales

There are about 80 species of ‘soft scale’ insects of the family Coccidae found in Australia. The ones I find most interesting are the pulvinariine soft scales which are known colloquially as ‘cottony scales’, ‘cottony soft scales’ and (my favourite) ‘cushion bears’. These common names help to describe the cottony egg sacs (ovisacs) of adult female scales. The image below shows adult female Pulvinaria dodonaeae on the leaves of a species of Myoporum.

Cottony soft scaleThe insect itself is brown in colour and the ovisac is the furrowed white mass behind. Pulvinaria dodonaeae is endemic to Australia and is not considered to be a pest. Its species name, dodonaeae, coveniently indicates some of its host plants are within the plant genus Dodonaea. One of the exotic (i.e introduced from elsewhere) cottony soft scales found in Australia goes by the name of Pulvinaria hydrangeae. Can you guess which plant it occurs on? Continue reading Cottony scalesShare this:
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