Friday 26 June 2015

Early invertebrate survey (the one that got away)

Wet weather and blustery conditions means that winged insects struggle to fly, instead staying hunkered down low in vegetation or hidden away in nooks and crannies (I wish it was the same for us ecologists).

Land East of the Railway Line

Earlier in the month, on a rare day of both sun and stillness, Surrey Wildlife Trust entomologist Scotty packed up his van and invertebrate surveying kit, stopping by to see what is happening under the radar of all the tourists and jet-setters.

Preparing sample tubes

Our task today was to check out some habitats which were missed off the previous surveys and needed looking at more closely. We've been keen to get back out to the Gatwick Stream since the flood alleviation project has come to a close...

Gatwick Stream grasslands

Wetland scrape with Great Reedmace (Typha latifolia), Gatwick Stream grasslands

Now the floodplain has had a full season of vegging up, in places it is looking quite stunning (albeit with the odd random exotic plant species cropping up). As the vegetation advances, the invertebrate lifeforms also begin to recolonise...

Agelena labyrinthica - Labyrinth Spider on dewy web

Underside of a Long-Jawed Orbweaver (Tetragnatha sp.)

A species of large diving beetle (Colymbetes fuscus)

Red-headed Cardinal Beetle - Pyrochroa serraticornis

Invertebrates form the essential base of many food chains and so can be excellent indicators of habitat quality. By seeing what species are dominating or what is absent, we can judge the success of our habitat management, then in a few years time we resurvey to measure the progress.

Gatwick Stream channel with its sculpted clay cliffs

The Gatwick Stream banks are still yet to green up, but even bare clay is appealing to some lifeforms, creating an interesting habitat matrix, suiting mining bees, mason wasps and beetle species. Even some birds too...

Kingfisher burrow

Here we had a brief interlude for some ancient bottle-collecting along the banks. These must have been underground for some time and washed out during the river re-alignment works...

Early 20th centruy Tizer bottle. "That belongs in a museum" 

Indiana Jones moment passed, it was time to look more closely at the pollen and nectar-gathering species...

Bumblebees on Fodder Vetch (Vicia villosa). Most were workers of either the Buff-tailed or White-tailed variety, as well as Tree Bumblebee

Corizus hyoscyami, aka the Cinamon Bug, or Squash Bug, or Scentless Plant Bug. 
(The perils of common names for invertebrates)

Over to another grassland area; Ashley's Field which is the subject of our green hay strewing project and home to our Honey Bee apiary, aka the 'Gatsbees'...

Ashley's Field - perhaps a little heavy on the Buttercup

Hitch-hiker: another Long-jawed Orbweaver

Into Upper Picketts Wood our the way to Goat Meadow, we stopped off to take a closer look at the understory.

Nut Weevil (Curculio nucum Scotty a nip with its sharp, finger-boring mandibles!

Mr Finger-borer unfortunately took a nose-dive before I could focus for a close up.
   Over to Goat Meadow; a quieter, sheltered area of grassland. This lovely scrubby matrix is a real haven for butterflies and Grass Snakes. 

A few molluscs have made their way here too...

Wandering Pond Snail (Radix sp.)

Brown-lipped Snail (Cepaea nemoralis)

Scotty spent some time sweeping and beating the willow and oak scrub, turning up many interesting things including this funky little micromoth...

Alabonia geoffrella, with its funky, upturned labial palps

And I swept this punky caterpillar...

Vapourer Moth caterpillar (Orgyia antiqua). 
The adult female moths are wingless and emit pheromones to attract in winged males

14-spot Ladybird (Propylea 14-punctata)

A type of treehopper (Centrotus cornutus), one of only two species which occurr in the UK

Glowworm (Lampyris noctiluca) larva, commonly found under the reptile refugia

Scotty then called me over to take a look at this little beauty... 

A lovely little Jewel Beetle (Agrilus sp.)

Jewel Beetles are not very common in this area, so this could be quite an exciting find. We cooed over it for a bit, turning it over in the tube and I popped it back onto the willow leaf to get a better snap. It didn't stick around for long and this was as good as it got...

Agrilus sp. indet. cf.bickerisabloodymindedliberator

On handing Scotty back the empty tube, his face fell... Apparently there are over 3000 species of beetle in this single genus and he needed to check it under the microscope to identify to species level! Ooops.

...Fly, my pretty!

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