A rainbow worm

After a long overwintering period with little activity, BugBlog comes to life thanks to these active earthworms. Using my shoe as a measuring device (cropped out of the photo) and back at home I estimated that is was over 11 cm long. There were several of these worms crossing the path on a wooded patch on the university grounds, under the rain. I usually shy away from identifying worms, but the striking colour of the clitellum - the orange band towards the front of the worms called my attention. I used the Opal Identification guide Their colour, large size and yellow tail tip narrowed down to Blue-grey worm (Octolasion cyaneum), although I think rainbow worm would be more appropriate. The species is found on the topsoil on a range of habitats. This worm had some visible injuries - possibly caused by failed predation attempts by Blackbirds or Carrion Crows.

More information
Earthworm guide. Opal. here.

Spring unfurling

 We rose to quasi tropical temperatures for mid February today, reaching 15.5 oC in this clear sunny day. Many overwintering bugs woke up, stretched and started buzzing about. Tens, hundreds of 7 spot ladybirds everywhere, coming out from folded, dried up leaves and positioning themselves on sunny spots. I disturbed a green caterpillar while gardening and woodlice were also active.
 The garden is still very sparse in the flower front. Today the first tete-a-tete daffodil opened and there are a few primroses. That is a problem if you rely on nectar and pollen for energy. Two droneflies (Eristalis tenax) including the female on the top shot fed on honeydew on the ivy. Notice its long, dark proboscis licking the leaf and the spots of honeydew on the leaf on the foreground. Later one of them flew to the Lauristinus, which is now in full bloom, where it joined a honeybee and another early hoverfly species (Meliscaeva auricollis).  Marmalade flies (Episyrphus balteatus) were also about.

Dronefly on Laurustinus

A dead queen wasp

Marmalade hoverfly, Episyrphus balteatus

The hoverfly Meliscaeva auricollis also in Laurustinus

Waking up to served breakfast

 I ventured out to the garden today despite the wind and occasional shower. Plants are starting to awaken: leaves sprouting, two daffodils about to open and a single bowed down Hellebore flower. 7 spot ladybirds like to hibernate between the waterproof leaves of the spurge and today the bright sun woke some of them up. They must have felt very lucky, as colonies of aphids were sitting on the very same shoots. I didn't see any eat aphids, in fact the aphid in the photo below was sitting on the ladybird's head just before I took the shot. But give them time and the spurge might be cleared up of aphids. Something I found surprising is that the aphids are reproducing, and it is february, weren't they supposed to be eggs at this time of year?

Buzzing laurustinus

 I planted a laurustinus (Viburnum tinus) bush on a large pot a couple of years ago and placed it opposite the window where we eat, a sheltered patio area. I did not realised at the time what a great location this was and what a fantastic bug magnet this bush is. One of the best features of lauristinus is its long winter flowering season (from October to May). My new vantage point has also revealed that their pollen and nectar rich flowers are often visited by honeybees, hoverflies and droneflies during mild winter days, as you can see in the photos below, all taken a few days ago. Come spring they are also visited by butterflies like the Holly Blue and early bumblebee Bombus pratorum queens. As this hardy bush does not mind shady conditions, their pink-white flowers are a good way of lightening dark corners of the garden.

A poor shot of Episyrphus balteatus

Eristalis sp. Dronefly.

The one on top of the post is possibly Meliscaeva auricollis, thank you Geoff F from WAB for the tentative ID given the difficult angle.

An early start for the butterfly year

I just sent my record of the first butterfly of the year to the fantastic Woodland Trust site nature's calendar, a citizen science website which allow enthusiast naturalists to add their phenological data. It has fantastic live interactive maps and data is also used for scientific projects. Only once before I had my first butterfly of the year in January, but Sunday's (8th) was the earliest. A Peacock, flying strong, but coming close enough to us for ID (the photo above is from a few years back). We have had very mild weather since before Christmas, and this is stirring up overwintering bugs and bringing them out. All five butterflies, which spend the winter as adults (Brimstone, Small Tortoiseshell, Commas, Peacocks, and Red Admiral) had been reported in the Butterfly Conservation website by the 8th of January.

Twelve bugs of Christmas

Today we woke up to a mild, sunny day and I was pleasantly surprised by the diversity of active bugs about. I made a count of species and when I got to twelve I was reminded of the traditional carol and made up a buggy version:

12 ladybirds walking | 11 winter-gnats dancing |10 honeybees buzzing |9 bluebottles basking | 8 leafhoppers leaping | 7 woodlice hiding | 6 hoverflies flying | 5 snails sleeping | 4 spiders weaving | 3 harlequins | 2 drone flies | and a bumblebee on ivy

The honeybees in the local wildlife garden were coming out tripping over each other and ladybirds (7 spots mostly but also harlequins and 22 spots) were awaken by the mild temperature. I counted 5 spider species outside (Tegenaria, Zygiella, Pholcus, Steatoda, Linyphia). The main surprise was the bumblebee worker, extremely fast and active and with pollen baskets full with pollen.

Here is a slideshow of bugs seen and photographed today

How do bugs cope with winter?

We've had a couple of frosts in the last few days. Despite the die-hards which allow me to post occasionally these days, most insect species are nowhere to be seen throughout winter. How and where are bugs surviving the cold weather? There are various ways in which invertebrates go through the winter.

Far, far Away
Some - I'd say the lucky ones, avoid winter altogether - they are far, far away during winter, having migrated to warmer areas around the Mediterranean. These include several butterflies, moths, hoverflies and dragonflies (Red Admiral, Painted Lady -above - Silver Y and the Migrant Hawker are examples) which often lack a frost-resistant stage in their life cycle.

Slowing Down
Others stay to brave the elements, a few of them even carrying on more or less as normal, but at a much more sluggish pace. These are the invertebrates that enjoying the occasional sunbathing during rare winter sunny spells: Bluebottles (above), Winter Gnats, the window spider (Zygiella x-notata). Some moth caterpillars, like the Ruby Moth caterpillar, are found active in the middle of winter. A few bumblebee populations are starting to behave this way as the climate warms and they can make use of winter flowering resources.

Dormancy
Many insects enter a dormant state or diapause: this is the scientific term to describe what we often call 'hibernation': organisms enter a physiological state, dormancy or diapause, in which growth and feeding pretty much stop, and metabolism is very reduced. To protect their bodies against the damaging effects of freezing, some chemicals (glycerol and anti-freeze protein are two of them) are produced in their bodies to maintain cell stability and aid survival under low, often freezing, temperatures. Overwintering can occur in any stage of the life cycle depending on the species or taxonomic group  - egg, larva or nymph, pupae or adult (imago).

The beautiful blue silk cocoon of a Enoplognatha spider, ready for winter.

For example grasshoppers, aphids and many spiders overwinter as diapausing eggs. Many dragonflies and damselflies overwinter underwater as nymphs. Many solitary bees overwinter as pre-pupae in their nest cells.

A fully developed Noctua moth caterpillar in early spring

Some butterflies and flies overwinter as pupae, whereas some butterflies (Comma, Small Tortoiseshell, Brimstone), Ladybirds, queen wasps and queen bumblebees hibernate as adults. Many solitary bees are already imagos in their cells, waiting for the right time to emerge.
 I will keep my eyes open for bug life throughout the winter and be on the lookout for any stirrings indicating that springs is coming.

Foggy morning

The fog painted the spider webs hanging from bushes and fences this morning with pearly dew drops. It made evident that at least three spider species are still active. On the photo an Araneus diadematus web, we also saw Zygiella x notata and Linyphia triangularis webs.

Winter bees on Mahonia

A lovely, still sunny day, I walk to a clump of Mahonia on a corner of an avenue. I have posted about this bug magnet in previous years (here, here and here) At this time of the year, Mahonia (Oregon Grape) is on bloom, its sweet scent and profuse, sunny-bright yellow flower spikes attract all late nectar lovers. Today, the bushes were busy, Bluebottles, Drone flies, honeybees and three (!) bumblebee species were feeding on it. A Bombus pratorum queen about to land, with a dronefly on the foreground on the top photo. This is one of the garden plants that are likely to have contributed to favour winter colonies in bumblebees. Bugs love this bush, and so do I. 

Bombus terrestris queen. I have seen a worker this week too.

Bombus hypnorum

Honeybee

Dronefly and bluebottle

Angle Shades caterpillar

After several weeks of frost and snow, and the coldest December for 120 years, we venture in the devastated garden to get some fresh air. Despite the frost, while brushing the leaves from the path, we came across a lively and fat Angle Shades caterpillar (Phlogophora meticulosa). Larvae of this common species of moth can be found all year round, while adults fly from May to October. Although, considered a pest in gardens due to the wide range of caterpillar feeding plants, the adults are large, handsome moths with unusual curled wings which make them look like a shriveled leaf, with neat brown and pink patterns. The larvae, which can be green or brown, are active during the winter, and hide under the leaf litter feeding on whatever green plants happen to be around. Come the end of March, they are ready to pupate and the fresh generation of moths will appear from mid April. In the summer, these local moths will be joined by migrant ones from the continent, as this species is also a common UK migrant.
Below there are a series of images illustrating the life cycle of this moth.

17/03/07. A large, drowsy caterpillar...

 Falls on its back, and within 24 h...

it has pupated.

The pupa took half an hour to reach the deep brown colour from the photo above.

16/04/07. A freshly emerged Angle Shades dries up on Cytisus bloom.

16/05/08. An adult found in the house quenches its thirst on Iberis.

For more information on moths see UK moths.

November bug magnets

I went for a walk this afternoon to re-acquaint myself with my clean and repaired camera. After spending almost three weeks camera-less, it was great to have it back. I just walked back to the spot where a few days ago I spotted the B. hypnorum and waited around the sweet smelling Mahonia bushes trying to spot more bumblebees. There were flies (Bluebottles and a smaller species) and wasps around, but my patience finally paid when I saw the distinctive large and dark shaped of a bumblebee amongst the flowers. Not a B. hypnorum, but a worker B. terrestris, stayed just for a few shots (top).

 The second bug magnet today was Ivy. There were dozens of male wasps feeding on Ivy flowers on the wildlife garden. Their large antenna reminded me of mountain Ibex males. I am not very good identifying wasps, although in a post in WAB today somebody pointed at a very informative webpage to identify them. I will update the post if I manage to get an ID. Around the ivy there were also feeding Bluebottles and a parasitoid wasp.
 The third bug magnet was a non-native bush related to the Ivy, the Fatsia japonica. Here the ubiquitous bluebottles were the only insects around.

Winter active bumblebees

We had our first frost yesterday, and it was also a frosty morning today. But coming back home this afternoon, with the light already going weaker, I came across a Tree Bumblebee, Bombus hypnorum feeding on a large Mahonia bush. I have posted before on this bumblebee, a recent natural colonist in the U.K. In the last two decades, reports of winter active bumblebees - mostly Bombus terrestris - have steadily been accumulating, especially in the south of Britain. Queen bumblebees are occasionally active in warm winter days, but the reports referred to queens collecting pollen - a sign they are actually nesting, not hibernating - or workers - indicative of active nests. These observations depart of the usual bumblebee life cycle in northern Europe, where winter hibernation of queens is the usual case. Whereas there are many native flowers in bloom during the winter to support a second generation in the Mediterranean, this is not the case in northern Europe. What resources are active winter bumblebees using? Stelzer and coleagues tested the hypothesis that winter bumblebees are making use of non-native flowers in parks and gardens. To do this, they set up B. terrestris colonies and followed them during two winters. In the second winter they introduced a new technique - micro-tagging - which allows automatic recording each time the tag passes nearby the tag reader set at the nest entrance. They attached the small RFID tags to the thorax of 64 individuals, and positioned a micro-balance at the entrance of the nest so that bumblebees also weighed themselves as they went in and out the nest, so that they can estimate the increase of weight of each bumblebee at the return of each foraging trip. Their results showed that bumblebees in their experimental nests were able to forage for nectar successfully during the winter, with nectar returns per hour foraging comparable or higher to yields obtained during spring and summer.

The researchers also carried out transects in the Royal Botanical Gardens in Kew to ascertain which plants were being visited by Bumblebees during the winter:
Only cultivated plants were in flower and the main plants visited by B. terrestris were Arbutus unedo and Salvia uliginosa in October (38.2% and 42.3% of the total recordings during that month, respectively), Arbutus spp. (A. unedo and A. x andrachnoides) (31.2%) and Mahonia spp. (Mahonia x media ‘Winter Sun’, Mahonia x media ‘Charity’ and Mahonia lomariifolia) (43.7%) in November, Mahonia spp. (69.0%) in December, Salix aegyptiaca in January (48.2%) and Lonicera fragrantissima (24.1%) in February.

The high yields obtained by the experimental bumblebees might be explained by the nectar sources being large bushes with large volumes of nectar per flower and the flowers being in large inflorescences, such as the ones in Mahonia (see photo above) and willows. In addition, there is no competition for nectar and pollen in the winter months by other foraging bees. Only a few honeybees were around, and these are not active below 10oC, while the bumblebees can forage at temperatures close to 0oC. Further work is necessary to assess if this generation is actually successful, that is, if males and queens are produced, but these results show how human impacts - gardening possibly coupled with climate change- have unexpected effects on the life cycles of native organisms.

Stelzer RJ, Chittka L, Carlton M, & Ings TC (2010). Winter active bumblebees (Bombus terrestris) achieve high foraging rates in urban Britain. PloS one, 5 (3) PMID: 20221445

The Winter Ball

The sun appeared shyly behind the clouds after a shower. It is milder than in the last few days today and I wandered out in the garden to try and get some shots of the Winter Gnats (Trichoceridae). These are dipterans which are active on the winter months. Males gather in swarms from a few to dozens of individuals in assembly points over prominent bushes or trees and fly bobbing up and down. If you can get close to the swarm they might take you as their 'assembly point' and dance over your head. Occasionally each individual alights on the bushes. That's how I got the still shot of one.

Females enter the swarm to chose a male and mate.
Other than the Winter Gnats there was little active buglife in the garden. Three 7 Spot Ladybirds are hibernating in between the leaves of the Monkey Puzzle.

Hibernating 7-Spot ladybirds

Bumblebees!

The first bumblebee of the year stumbled across my path today. It was close to a large clump of flowering Mahonia, but on the footpath, so I moved it to the flowers. It was a white-tailed queen bumblebee, Bombus lucorum. Recent bumblebee records from the BWARS (Bees Wasps and Ants Recording Society) site indicated that, instead of overwintering queens, there are now overwintering colonies -mainly of the Buff-tailed, Bombus terrestris but also Bombus pratorum, so that workers can be seen foraging in the winter. As far as I know this has not happened in Northern England yet, so the first bumblebees of the year are sleepy-looking queens in search of nectar and a nesting site. It was sunny and quite warm in the morning, so this bumblebee was awaken and came across this patch of flowers. I guess in the countryside must be quite tricky to find nectar this time of year, with gorse, snowdrops, lesser celandines and few other plants in bloom. Cities and their parks and gardens have much more in offer, rosemary, Mahonia, heathers, Hebe and many other mid-winter flowering plants, and I wonder if this - combined with milder winters - has something to do with this change in reproductive strategies. It would be interesting to test this comparing the  strategies of countryside versus urban bumblebees.