Tag Archives: Tadpoles

Natural History, Nature Reserves

Hoverfly Diversity at Gunnersbury Triangle

Criorhina ranunculi male, courtesy of Mike Fray
Criorhina ranunculi male, courtesy of Mike Fray

Well, at last it’s warm. The anticyclone is heating up the air nicely, a couple of degrees warmer each day. The air is buzzing with hoverflies, and luckily with Mike about, we can actually put names to them. This one, a really remarkable bumblebee mimic, is Criorhina ranunculi – nothing to do with buttercups (Ranunculus), but a species whose larvae live in rotting wood, and it does have an odd nose (rhino-). Quite an unusual species.

Myothropa florea, a wasp mimic hoverfly
Myothropa florea, a wasp mimic hoverfly

This one, Myothropa florea, is a much more typical hoverfly, mimicking a wasp. Mike says he’s recorded some 18 species in the Gunnersbury Triangle LNR.

Nomada cf flava male cuckoo bee
Nomada cf flava male cuckoo bee

This is a male Nomada cuckoo bee, a brood parasite of other bee species. Its jizz is quite wasp-like in flight, with a flash of aposematic yellow-striped abdomen looking distinctly worth avoiding. At rest, it looks much more like the bee that it is.

Andrena (broad-headed) bee
Andrena (broad-headed) bee

 

Andrena cf nigroaena on new Hawthorn leaf
Andrena cf nigroaena on new Hawthorn leaf

This honey-bee-like insect, in contrast, is obviously a bee, and not a parasite. If you’re used to honey-bees, you’ll notice it has a markedly short head, shorter than it is broad: all the Andrena genus are like this. The head can be short because the tongue is also short, the genus being adapted to short-tubed flowers, so evolution has economically saved energy on building a wastefully long head.

Tiny tadpoles in the shallows
Tiny tadpoles in the shallows

Down at the pond, the sun sparkled on the clear water; a newt or two lurked between the weeds; and dozens of tiny tadpoles wriggled in the shallows. The Mallard pair swam about just below us, greedily feeding. I hope they miss some of the tadpoles.

Women volunteers at work
Women volunteers at work

We hammered in a line of posts for the log hedge, to reduce the number of sticks finding their way into the pond.  The ground was rather stony in places, and the iron bar came in handy to break through the stony layer first.

As we did the butterfly transect (Green-Veined White, Brimstone, Holly Blue, Speckled Wood, Large White), we saw a Sparrowhawk swoop into a tree, whistling to his mate. So it seems they’re nesting here again this year.

Jo planting out cornflowers, poppies, climbing nasturtiums and foxgloves
Jo planting out cornflowers, poppies, climbing nasturtiums and foxgloves

Back at the ranch, Jo was planting out some nice-looking small cornflowers, poppies, climbing nasturtiums and foxgloves raised by the Chiswick Horticultural & Allotments Society’s greenhouse team.

Two days later, the Swifts arrived in the skies over Chiswick, bringing their screaming flight calls to announce summer.

 

Natural History, Nature Reserves, Wildlife

Spring has sprung

Ramshorn pond snails
Ramshorn pond snails

Today dawned foggy and cool, but the sun soon burnt its way through and it became a hot spring day. I spent most of it reroofing the tool shed at the Gunnersbury Triangle nature reserve. It was in tatters after at least one hard winter, and it was an interesting exercise peeling off the layers hopefully tacked one on top of the leaky other. I then removed three full boards from the roof, complete with what I’m sure any mycologist would have found a fascinating colony of wet rot fungus, together with several wriggly centipedes and a lot of woodlice.

As it grew hotter on the roof, I was joined by at least two species of hoverfly, one large, dark, and almost unstriped. A brimstone butterfly chased around with a smaller white, perhaps a green-veined or an orange tip. A comma butterfly wandered about. Down below, the stinging nettles, hops, and garlic mustard (ideal for orange tips) are coming up nicely, but there’s too much cow parsley and some volunteers are pulling a lot of it out.

Newly-Hatched Tadpoles
Newly-Hatched Tadpoles

At lunchtime I walked down to the pond. Chiffchaffs were singing all over; the pond was suddenly covered in pond skaters (Gerris) with one or two whirligig beetles. The tadpoles have hatched out into a wriggling mass.
Spring has sprung.