Category Archives: Wildlife

Oak Galls: Wasp vs. Plant

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Oak trees are home to more than 30 species of gall wasp. The larval stage of these insects induce the plant to produce abnormal growths, known as galls, which enclose and protect them as they develop.

Oak gall wasp larva IV

Galls come in a variety of fantastical shapes, each unique to particular species.

Oak marble gall

Marble galls

Hard woody spherical galls up to 25mm in diameter on the oak stems. Initially green but later become brown.

Created by: Andricus kollari

Oak apple gall

Oak Apple Gall II

These galls have a spongy texture and are brownish white, tinged with pink.

Created by: Biorhiza pallida

Common spangle gall

Common Spangle Galls II

Yellowish gingery brown disc-shaped galls on the underside of oak leaves in late summer and early autumn.

Created by: Neuroterus quercusbaccarum

Silk button spangle gall

Silk Button Surfeit

Golden brown discs with a depressed centre on the underside of oak leaves in late summer through to early autumn.

Created by: Neuroterus numismalis

Knopper gall

Knopper gall

The acorn becomes a ridged woody structure. The gall is initially yellowish green and sticky but later greyish brown.

Created by: Andricus quercuscalicis

Cherry gall

Oak Cherry Galls

Yellowish green or red spherical galls up to 20mm in diameter on the underside of oak leaves in late summer and autumn.

Created by: Cynips quercusfolii

It gets complicated…

Oak gall wasps have complex life cycles, with alternating generations that are either sexual with males and females, or asexual with females only.

The two generations of wasp often produce different types of gall on different parts of the tree, and in some species the two generations alternate between native and non-native species of oak.

Oak Gall Wasps VI

There are also wasps which specialise in injecting their eggs into oak galls. Their larvae then eat the resident eggs or larvae before they emerge.

Chalcid Wasp

The example above shows a type of Chalcid wasp investigating a fresh oak marble gall.

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Puss Moth Metamorphosis

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I’ve photographed puss moth caterpillars (Cerura vinula) before, but this summer I wanted to follow them through all 5 stages, or ‘instars’, of their larval development.

Luckily I discovered a batch of recently laid puss moth eggs by searching the exact same aspen sapling chosen by another adult female the previous year.

6 June: Unhatched Ova

Puss moth eggs (Cerura vinula) on aspen

Cluster of puss moth eggs (Cerura vinula) on underside of aspen leaf

12 June: Hatched Ova

Hatched eggs of puss moth larvae (Cerura vinula)

Hatched eggs of puss moth larvae (Cerura vinula), showing signs of early feeding activity nearby.

12 June: 1st Instar

The ‘puss’ moths look a lot more cat-like at this early stage in their development I reckon.

First instar puss moth larva (Cerura vinula) on aspen leaf

1st instar puss moth larva (Cerura vinula) on aspen leaf. The distinctive tail-like appendages are already present.

1st instar puss moth siblings (Cerura vinula) feeding on aspen

1st instar puss moth siblings (Cerura vinula) feeding on aspen

15 June: 2nd Instar

I’d received a shock on my visit the previous day when I found the caterpillars frozen rigid in position, with their backs arched and tails in the air. They looked decidedly dead and I thought they must have been parasitised. Today, however, they were re-animated once more.

Puss moth siblings sharing the same aspen leaf

Puss moth siblings sharing the same aspen leaf

Puss moth siblings on shared aspen leaf

The puss moth siblings were running out of space on their steadily consumed leaf and occasionally paused to whip their tails furiously at each other.

Second instar puss moth larva on aspen leaf

Close-up of 2nd instar puss moth. The jagged tentacles above the head are very prominent at this stage, unlike in the fully mature larva.

24 June: 3rd Instar

9 days later, after vanishing for several days, the two siblings had relocated further up the branch they originally hatched on. Neither was particularly active in the midday heat.

Third instar puss moth larva resting on silk pad

3rd instar puss moth larva resting on silk pad

Third instar puss moth larva resting on silk pad on aspen leaf

The distinctive saddle patterning of the puss moth caterpillar is much more visible by this stage.

28 June: 4th Instar

It lashed with rain on my next visit and the only visible puss moth was trying its hardest not to get pummeled off the leaf. Its silk pad lashed to the surface provides a firm anchor for feet to grasp.

4th instar puss moth on aspen leaf

4th instar puss moth clinging to wet aspen leaf. The hump on its back is now filling out.

4th instar puss moth larva

At this stage in its development the puss moth’s body has begun to envelop its head and the tentacles appear to have retracted.

9 July: 5th Instar

A further 11 days later I returned to find only one of the original 4 puss moth siblings remaining, now in its magnificent mature larval form.

Fifth instar puss moth larva

5th instar puss moth larva. All the outlandish features of the mature larvae are now present, including the lurid pink face, flagellae and false eye spots.

Fifth instar puss moth larva detail showing extended pink flagellae

Detail showing extended pink flagellae. When threatened the puss moth extends these whip-like appendages from its tail end and waves them around crazily.

To be continued…

Soon after reaching this mature larval stage the puss moth stops eating and leaves in search of a safe place to pupate. Its transformation into the furry white adult moth can then begin. Despite much searching I couldn’t locate any pupae. Next time maybe!

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WPOTY 2014: Shortlisted

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Another year, another shortlisted image! This time in the ‘Invertebrates’ category:

Pond skaters

River sprites

Canon 600D + 100-400mm f/4.5-5.6L IS USM lens; 2 sec @ f/40; ISO 100

This is a long exposure image of pond skaters (Gerris sp.) in motion, taken in the shady bend of a local river one summer afternoon. Shortly after this frame was captured my tripod toppled over and the camera went for an expensive swim!

Unfortunately this year’s entry again failed to make the final cut. Congratulations to The Winners.

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Amphibian Kama Sutra

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Common toads in amplexus

Common toads (Bufo bufo) spawning

After emerging from hibernation in early spring, toads migrate back to their breeding ponds.

Males fight to secure mates and often outnumber the females at some sites. When this happens the female may be grasped by several males in a position known as ‘amplexus’, as they compete to be in the best position to fertilise her eggs.

Common toads in amplexus

Group of toads in amplexus

Common toads in amplexus

Spawning might look fun but can also be life-threatening!

Common toads in amplexus

Toad sex is apparently a moveable feast!

The common toad is widespread in Surrey, however populations appear to be declining. Where toad migration routes cross busy roads there can be many fatalities, and local conservation groups police ‘Toad Crossings’ at dusk to help them safely across.

Common toad crossing track

This toad was late to the party, but managed to avoid oncoming traffic

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Spring Wood Ant Antics

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Wood ant with heather seed

Wood ant (Formica rufa) foraging in early spring

The wood ant mounds among the pine trees were beginning to stir on my visit to the RSPB’s Arne reserve in Dorset recently.

Nests become active in early spring when worker ants begin to forage for food items and building materials to repair damage sustained over the winter months. Badgers, magpies, jays and other animals often raid wood ant nests for food.

Wood ant carrying twig

Wood ants are capable of carrying relatively heavy loads

Wood ant colonies can contain up to half a million individuals. On sunny days worker ants ‘sunbathe’ at the nest entrance to absorb heat and then re-enter the nest to release it – keeping it at a steady temperature. When the nest becomes too warm they open small vents to cool it down.

Wood ants at nest entrance

Sunbathing worker ants at nest entrance

The ants are particularly aggressive in springtime as they re-define their territories. Sometimes ants from weaker neighbouring colonies are recruited by force and carried back to the main colony.

Worker ant carrying another wood ant between nests

This species of wood ant is classified as Near Threatened (NT) in the IUCN Red List and classified in Great Britain as Local. Numbers seem to be increasing in the south of England but it has become locally extinct in parts of its former range in the north and east of England, the Midlands and north Wales.

Photographing ants is always a challenge because they’re small and they move very fast. It’s a good idea to keep your trousers tucked firmly into your socks when lying on the ground this close to a nest full of them! They will bite occasionally but can’t pierce skin. The formic acid they squirt in defence is too weak to harm humans.

Harvest Mouse Survey

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Harvest mouse at night

Harvest mouse (Micromys minutus) captured on survey after dark

Last week I joined Surrey Wildlife Trust on a harvest mouse survey in wetland habitat beside the River Wey.

Harvest mice are tiny rodents 5cm in length. Their remarkable prehensile tails add an extra 6cm. They live in long tussocky grassland, reedbeds, hedgerows and around woodland edges, building a spherical nest of tightly woven grass, high up amongst the stems. We found several examples at this site:

Harvest mouse nest

Harvest mouse nests are woven from a mixture of living and cut grasses which provides excellent camouflage

Nests are the most obvious sign of harvest mouse activity since the animals are especially active around dawn and dusk and rarely spotted in the thick vegetation.

Dozens of rodent-friendly traps of different designs were set in the thick wetland reeds and grasses. Surrey Wildlife Trust staff and volunteers returned three times each day over the course of a week – at dawn, midday and dusk – to ensure that no trapped animals were left for any longer than necessary.

Rodent trap

Rodent trap baited with peanut butter, bird seed and dried blowfly larvae

After retrieval from the trap harvest mice are transferred to a transparent bag for weighing and sexing:

Harvest mouse in bag

Harvest mouse recovered from trap

Weighing harvest mouse

Harvest mice weigh only 5g on average

Once the details of each rodent have been recorded a small patch of fur is trimmed to identify any animals which are subsequently re-captured.

Harvest mouse being marked

Marking harvest mouse – a delicate operation!

The highest number of individuals captured was 12 one morning, making this the most abundant site for harvest mice in the county at present.

Harvest mouse in the hand

Harvest mice require very careful handling by trained experts

With thanks to Surrey Wildlife Trust staff and volunteers.

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Shortlisted: BWPA and WPOTY 2013

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Fox cub at night

Fox cub (Vulpes vulpes) in car headlights

Well it’s been another case of “nearly, not quite” in the furiously competitive world of wildlife photography this year…

WPOTY 2013

My image of a red fox cub in car headlights (above) was shortlisted in the Wildlife Photographer of the Year competition in the ‘Creative’ category, but progressed no further.

Driving home one night I encountered 3 cubs gamboling about in a narrow country lane without a care in the world. They were oblivious to the sound of car engines and headlights. I hope they survived to adulthood.

As any technically-fastidious wildlife photographer will tell you the term ‘creative’ is reserved for blurry, out-of-focus images, and this effort on my part made no attempt to challenge that prejudice!

BWPA 2013

In the domestic British Wildlife Photography Awards this year my image of a glow worm displaying against leaf litter was shortlisted in the ‘Hidden Britain’ category.

Glow worm

Glow worm (Lampyris noctiluca) displaying against leaf litter

Photographing glow worms is quite an adventure, and a frequently frustrating one, as my earlier blog post on the subject explains.

How short is ‘short’?

The BWPA shortlist comprises around 300 images we were informed, so the shortlist is not especially exclusive it seems! Winners have yet to be announced.

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