Walking with woodlice

The day started bright and warm, but I had my allocated wild slot in the early morning, so I decided to look and photograph some common woodlouse species. We tend to take these common invertebrates for granted, but woodlice are a diverse group with over 30 species in the UK with a range of habitat requirements, not all found on wood, and many species have quite restricted distributions. Five species are relatively easy to find and you are likely to have at least three in your garden, so my aim today was to find these common species.
  The Yorkshire Wildlife Trust's Wildlife Garden by Pearson Park was a good place to start, as Pill Woodlouse can reliably be found. And voila, a couple of Pill Woodlouse, Armadillidium vulgare, walking on the path greeted me, although they were in a bit of a rush and didn't stay around long. This species can survive in relatively dry habitats, and is not unusual to see it active in the open during the day. It can be found in sandy beaches, often under stones. Together with other related species it has the feature of being able to roll into a ball when disturbed, with its tough exoskeleton affording some protection to its softer underside.

Pill Woodlouse, Armadillidium vulgare, crossing the path at good speed

I then moved into the woodpile area. This is a shady, moist spot amongst trees. I looked under some logs and, squinting and getting really close I could see some Common Pygmy Woodlice, Trichoniscus pusillus. They are reddish and shiny, not very flattened and very tiny (up to 4 mm).

Common Pygmy Woodlice, Trichoniscus pusillus, on the underside of a log

 These little woodlice were in the company of the Common Shiny woodlouse, Oniscus asellus (above, one found under a brick) which looked like giants in comparison. This species reaches a maximum length of 16 mm, and are amongst the largest native species in the UK. The common shiny woodlouse is shiny and is quite flattened, mainly grey with paler patches and spots (where it stores calcium to form its exoskeleton).

 I went into a drier area, in the orchard, where there are loose bricks and pots over concrete. There I found one of the commonest species, the Common Rough Woodlouse, Porcellio scaber. It is a large species, slaty grey, with clear tubercles on its back. This species often forms large aggregations of various ages under logs, stones or bricks. This behaviour is thought to help reduce humidity loss.

Common Rough Woodlouse, Porcellio scaber, found under a pot

Under the same pot I found a Common Stripy or Fast Woodlouse, Philoscia muscorum. This species tends to have a dark head and a dark stripe along its back. It is quite colourful for a woodlouse and it keeps its body high when moving, which it can do quite quickly (hence its common name).

Fast Woodlouse, Philoscia muscorum, under a pot

That completes the group of common woodlouse species. But I had seen a few Rosy Woodlouse while moving some pots a few days ago. This is not very common, I tend to find single individuals under larger stones or under large pots that haven't been moved in a while, where there is enough damp organic material or mud. I thought I'd give it a try when I got back home. After lifting the pot and looking closely I did find a single one! They are 5 mm long, pink to orange, and have a yellow stripe on their backs and despite their size, quite obvious eyes. They have a rough surface, but my photo really didn't make them justice, see this one for a close look.

A Rosy or Pink Woodlouse, Androniscus dentiger, found under a large pot.

More Information

An identification key for the most common woodlouse species by the Natural History Museum, here.

A snail safari

It was drizzling when I left home for work, a perfect day to look for some active snails for 30 Days Wild day 2 (always look at the bright side of life!). I hadn't walked long when I spotted some Strawberry Snails, Trochulus striolatus on the stones lining a front garden, probably feeding on algae encrusting the stones. A little while ahead a Garden Snail, Cornu aspersum, also in a front garden, probably searching for something more substantial.  I popped into Pearson Park Wildlife Garden. It is hard to visit it without finding a Kentish snail, Monacha cantiana, which love to walk on the paths. I found one climbing on grass (top shot). Many Kentish snails or all sizes were active on a wet trunk by the path, amongst them a White-Lipped snail, Cepaea hortensis.
 At lunchtime, I popped out a wooded area on campus and rooted around in the undergrowth and inspected the underside of pieces of wood and rocks. My first find was a Draparnaud snail, Oxychilus draparnaudi under a very rotten tree branch. Later, inside a plastic pot (part of an insect hotel) I discovered a Girdled Snail, Hygromia cinctella, which was nice as it is a first record for this area.
 Once home I knew where to find a tiny snail: in my log pile. After finding many garden snails dormant in amongst the logs, I spied a small group of Common Chrysalis Snail, Lauria cylindracea, and the best thing is that they were also active!
 Today's total then of seven species of snails found in not much time. At least two other species are quite common within walking distance of home: the Brown Lipped snail, Cepaea nemoralis, the Garlic Snail, Oxychilus alliarius, and the Rotund disk, Discus rotundatus.

Strawberry Snails, Trochulus striolatus

Garden snail, Cornu aspersum 

White lipped snail, Cepaea hortensis.

Draparnaud snail, Oxychilus draparnaudi

Girdled Snail, Hygromia cinctella

The Common Chrysalis snail, Lauria cylindracea

If you like snails and would like to learn to identify them I recommend these two publications, a folded up laminated An Illustrated Guide to the Land Snails of the British Isles, and the 2nd ed. Land Snails in the British Isles (with identification keys and drawings), and of course follow James Morris-Harding's quest to see all British land snails in 2015 the Snail Trail, either on Twitter (@UKSnailTrail) or on his blog.
 And if you identify them, why not send your records to iRecord?

Bumblebee watching

I am doing 30 Days Wild with the Wildlife Trusts. My vague plan is to have an invertebrate emphasis, to make an effort to see more of them given the dismal, windy, cool spring we are having, and to revive the almost dormant blog. Bumblebees appear to be having a particularly bad year. The first workers have been few and small, and even if many of their favourite plants are blooming, I only see the single worker about every now and then. I decided bumblebee watching would be the first wild event of 30 Days Wild. After all, Bumblebees fly during cold, cloudy days.
 Over the years, I have introduced plenty of native plants in the garden, which attract an assortment of solitary bees, bumblebees and other insects. Primroses flower early in the spring and are visited by the Hairy Footed flower bee, Anthophora plumipes, and occasionally by Bee Flies. Later,  Welsh Poppies buzz with bumblebees collecting pollen. At this time of the year Hedge Woundwort (above, a bee's eye view of a flower spike) and White Dead-Nettles are in bloom, and they are followed by long-tongued solitary bees and bumblebees.
This afternoon I managed to see just two bumblebee species, the Carder Bee, Bombus pascuorum and the Early Bumblebee, Bombus pratorum. B. pascuorum is a long tongued bumblebee and likes flowers from the mint family. It visited sage and hedge woundwort, while B. pratorum has a very small tongue and likes flat flowers. It visited Alliums and White dead-nettles. I find that B. pratorum, despite its tiny tongue, sometimes steals nectar through holes at the base of flowers, or is small enough to get inside the flower and reach the nectar.

This Bombus pratorum was visiting White Dead Nettles in the front garden.

A Bombus pascuorum on the sage hedge.

Wildlife garden meadow unfurling

The meadow in the wildlife garden is growing fast, speckled with buttercups and with the wide geranium and cranesbills carpeting it. Today it was warmer than previous days, with sunny spells. In the morning, I checked for insects and spiders. Female wolf spiders, at least two species, basked with their egg sacs. I also spot several nursery web spiders, I try to get close without spooking them, slowly crouching down to their eye level. When they bask, they often cross their front legs in front of them (above), but if they sense danger, they spread them out or just dash down into the grass. I see several males, each of them with a distinctive colour pattern.

Rhopalus subrufus

The large narcissus fly, Merodon equestris, many around, my first of the year.

A Scatophaga sp. fly

A Lucilia sp. greenbottle

Mating 14 spot ladybirds.

An unfortunate 7-spot ladybird fell prey of the teasel.

Wolf spider with egg sac.

Amber snail, many on the rotting vegetation around the ponds edge.

Cheilosia sp. a hoverfly on a buttercup.

Mating Corizus hyoscyami

A very pale grey male.

The same male than the top shot.

No butterflies, today, just a few Mint moths, Pyrausta aurata, in the marjoram.

Awesome bee flies

Bee flies, Bombylius major have emerged in the warm weather and I have come across them in several places. Bee flies are early spring fliers, the peak of adult activity is in April and May. They are found throughout the UK, where this species seems to be expanding north. Thee are some cool facts about them.

A male at rest.

Parasitism. Bee flies are parasitoids of several species of ground-nesting solitary bees, including Andrena mining bees. Their larvae crawl into the bees' nests and feed on larvae of the host bee once it is fully developed. Only large populations of mining bees are able to sustain a parasitoid population, so the presence of the bee fly is an indicator of healthy mining bee populations.

Female loading her sand-brush

Egg shooting. Bee flies collect sand or dust at the tip of their abdomens (which looks a bit like a brush) to coat their eggs before laying, as the one above is doing. Why? It is unclear if it is to camouflage them or to make them heavier. Females lay eggs in a curious way. Instead of just getting into the bee nest to lay, they fly low over bee aggregations, and throw their eggs against dark spots resembling nest entrances, including shadows swinging their bodies against it. Bee flies can afford some inaccuracy when egg laying though, as females can lay thousands of eggs per day. Their unusual egg laying behaviour might have something to do with the fact that they are soft-bodied insects, and could be too susceptible to the bee's sting to actually risk a one-to-one confrontation with the female bee. This is how they do it, note the sand-brush at the tip of the abdomen:


Mimicry. As their name strongly suggests, Bee flies are flies that look like bees, that is they are bee mimics like many hoverflies: they are similar in size to a honeybee, brown-tawny and as furry, with quite long hairs, as a bumblebee. It is unclear though if they mimic bees to get close to their nests unnoticed or to avoid predation from insect eating birds or other predators. Other mining bee parasites do not resemble bees at all (I'm thinking the wasp-like Nomada bees) and actually get inside nests to lay eggs.
Look into their eyes. You can tell male and female bee flies in the same way that hoverflies: males eyes are larger and actually meet a the top of the head, while in females they are smaller and separated by a hairy patch. This suggests that males use the sense of vision to look for females. Males actually hover in particular spots some times high up, near flowers, possibly to meet females.

 

male

female

Male feeding on Lungwort showing the fully extended tongue

Look at that tongue! One of the most impressive features of bee flies are their proboscis. These spear-like, non-retractable structure at the front of their head looks positively dangerous (like a giant mosquito!), however, it is harmless, its only purpose is to allow the fly to reach and suck nectar from flowers with deep, narrow corollas. Their mouth parts can be extended further as they feed to as long as their total body length.

A male feeding on grape hyacinth on Monday

Fantastic fliers. Bee flies are very fast and agile fliers, they hover a lot and can fly in any direction, including backwards. They don't settle to feed on flowers like hoverflies, instead, they behave more like a Hairy footed flower bee, or a Hummingbird Hawkmoth: their wings never stop moving when they feed from flowers, they are actually virtually invisible. They use their spindly legs to stabilise themselves in front of the flower. Males will hover at height, as many hoverflies do, and spin when they meet females.

Bee fly feeding on primroses on Monday

Pollinators. Bee flies feed on early spring flowers: Primroses, Grape-hyacinths, Forget-me-Nots, Violets, Lung-wort, Lesser Celandines and Wood Anemones. They will also feed on Blackthorn and sallows. Bee flies not only feed on nectar, they also consume pollen, with females feeding on pollen to a larger extent than males. They can be effective pollinators of these early plants.

A basking Bee fly yesterday.

Basking. Bee flies are active in warm, sunny days, and they like to bask to thermoregulate, sitting still, with their wings kept open at an angle. Then, you can try and identify the species as the wing patterns - hard to see in flight - can be diagnostic. The most common species, the large bee fly, Bombylius major, has a distinctive dark edge at the front of their wings.

More information
An identification sheet of British Species by the BRC. Click here.

Natural History Museum page. Click here.

Boesi, Roberto, Carlo Polidori, and Francesco Andrietti. "Searching for the right target: oviposition and feeding behavior in Bombylius bee flies (Diptera: Bombyliidae)." Zoological Studies 48.2 (2009): 141-150.

Jacquemyn, Hans, et al. "Biological flora of the British isles: Primula vulgaris Huds.(P. acaulis (L.) Hill)." Journal of ecology 97.4 (2009): 812-833.