Friday, 24 February 2012

Bee and snowdrops

The bees were out and about in the wildlife garden today. This one was feeding on snowdrops and stopped to clean itself up hanging from a single leg from a ragged flower. It's head, body and pollen baskets had orange pollen, presumably from the snowdrops as there was little else flowering about. In the pond, water boatmen were active. It is great to see bugs every day and spring arrived surprisingly early.

Thursday, 23 February 2012

More awakenings

 The early spring temperatures continued today. Ants were scouting out of their nests, sage leafhoppers were active and honeybees and droneflies enjoyed the Laurustinus. I waited until the bee and the dronefly visited the same inflorescence to take the above shot. I wonder if the Laurustinus flowers change colour when they are pollinated, in the same way as the Horse Chestnuts, white when fresh and turning red when already pollinated and stop producing nectar. 

We counted over 100 7-spot ladybirds in the garden. Some were eating aphids on the spurge.
The entrance of the burrow of a large Amaurobius spider under a garage roof. If you click to embiggen you can see the remains of a wasp a Harlequin and some wings I cannot identify, possibly from bluebottles.

A green shieldbug, Palomena prasina, on its dark winter attire came out of its overwintering refuge.
 Wolf spiders enjoyed the sun on the sunny side of the garden.

Tuesday, 21 February 2012

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

Saturday, 18 February 2012

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?

Tuesday, 7 February 2012

The impact of Harlequins on native ladybird fauna

ResearchBlogging.orgHarlequin ladybirds (Harmonia axyridis) are one of the most obvious invasive species in the UK. They are large and voracious and there was much speculation on their potential negative impact on the native ladybird fauna, given that they are regular predators of other ladybirds, especially during the vulnerable larval and pupal stages. An open access paper published today by Helen Roy and collaborators uses a powerful combination of citizen science (in the form of Ladybird online surveys) and systematic surveys to address directly the impact of Harlequins on the distribution and abundance of eight once common and widespread ladybird species in the UK, Belgium and Switzerland. Their statistical analysis on geographic distribution addressed the impact of the arrival of Harlequins on each species for well-sampled km2.
 The results are very clear, but also worrisome: the arrival of Harlequins had a negative impact on the distribution of 5 out of 8 species in Belgium and on 7 out of 8 species in Britain. The effect was large and the affected species have now contracted in range. The effects were striking for the small 2 spot ladybird, Adalia bipunctata, - a tree specialist - , which declined a 30% in Belgium and 44% in Britain in the 5 years following the Harlequin arrival. Although some of these species that were already declining, the presence of the Harlequin intensified the rate of decline.
Figure 1 Effects of Harlequin arrival on the distribution of eight native ladybirds based on predictions for an average 1-km2. Prediction is based on the fixed effects of the models and ignores random variation in occupancy among specific 1-km2. Absent assumes the 1-km2 is not colonized by the Harlequin, and present assumes the 1-km2 was colonized in 2001 (Belgium) or 2004 (Britain) by the Harlequin. Note that our predictions are shown in the measurement scale (probability of occupancy), rather than the modelled scale (logit). (from Roy et al 2012)
  The systematic surveys of ladybird abundance in the tree habitats favoured by Harlequins supported these results and showed that the numbers of all native ladybirds decreased since their arrival, especially markedly in the UK. The only species relatively immune to their invasion is the 7 spot ladybird, a large species that favours herbaceous vegetation and is less likely to overlap in niche with Harlequins.
 Local or regional extintions of some tree specialist species seem like a certainty, and the impact this will have on agricultural systems is hard to predict. The following gallery is a celebration of the diversity of native European ladybirds, with the species used in the study.
Pine ladybird, Exochomus quadripustulatus
 Orange Ladybird, Halyzia sedecimguttata
A winter aggregation of 7 spot ladybirds, Coccinella septempunctata
Cream Spotted Ladybird Calvia quatuordecimguttata
 10 spot ladybird, Adalia decempunctata
2 spot ladybird, Adalia bipunctata
14 spot ladybird, Propylea quattuordecimpunctata
22 spot ladybird Psyllobora vigintiduopunctata 

More information
Roy, H., Adriaens, T., Isaac, N., Kenis, M., Onkelinx, T., Martin, G., Brown, P., Hautier, L., Poland, R., Roy, D., Comont, R., Eschen, R., Frost, R., Zindel, R., Van Vlaenderen, J., Nedvěd, O., Ravn, H., Grégoire, J., de Biseau, J., &; Maes, D. (2012). Invasive alien predator causes rapid declines of native European ladybirds Diversity and Distributions DOI: 10.1111/j.1472-4642.2012.00883.x

Gardiner MM, O'Neal ME, & Landis DA (2011). Intraguild predation and native lady beetle decline. PloS one, 6 (9) PMID: 21931606

Gagnon AÈ, Heimpel GE, & Brodeur J (2011). The ubiquity of intraguild predation among predatory arthropods. PloS one, 6 (11) PMID: 22132211

Sunday, 5 February 2012

Three Orange ladybirds

There is a cemetery near our house which has become a woodland in the midst of the city. The old headstones, most covered on Ivy, are quite popular with ladybirds. These Orange Ladybirds Halyzia 16-guttata had found shelter under the nooks of the carved headstones, or next to Ivy stems. They are beautifully patterned, with transparent edges around the elythra and pronotum: you can see its head, which is tucked, in a tortoise-like way, underneath its partially transparent pronotum.

This species feeds on mildews. It used to be relatively rare, a marker species of old woodland, and associated to Oak, but in the last couple of decades it has broadened its diet and now feeds on Ash and Sycamore mildews, and it has become much more widespread.

Have you seen a ladybird? Record it at the Ladybird Survey Website