7 spot ladybird

Yesterday there was a gap in the 31dayswild theme this month, but not to worry, it wasn't so much due to my inability to see and photograph a suitable invertebrate, but more to the overabundance of them as I visited a local nature reserve, but you may want to go to my Wild at Hull blog to find out. So, continuing in today's stormy day 7, I bring you a fresh 7 spot ladybird. Despite the abundance of Harlequin ladybirds in the garden, 7 spots seem to be having a good season and I have seen them regularly this year. This one was giving this knapweed bud a good check for aphids.

Cemetery Bugs

There is a large cemetery nearby and today me youngest daughter came with me and decided to have a bug safari. It was the first visit in the year that I have taken many more invertebrate than bird photos.

A pine Ladybird on orange lichen, Xanthoria parietina 

A group of the blind millipede Blaniulus guttulatus, with Porcellio scaber and a while slug under a piece of wood

A colourful cluster of Harlequin ladybirds appeared to have emerged from a crack in a damaged tree and some were flying off

Peacock sunbathing

A carpet of Lesser Celandines

Flowering Willow

Harlequins and Amaurobius (with nests?) under broken headstone.

Elder aphid networks

The photo above shows a dense colony of Elder aphids, Aphis sambuci, many individuals of different ages feeding close together. They are likely to be all a clone, female descendants of a single founding female that emerged from an egg early in spring, and identical genetic copies of her. Elder aphids forms this characteristic ash grey patches on tender elder stems. The aphids suck the elder sap using their piercing mouthparts. Having a close look at elder aphids gives you an opportunity to learn to learn about ecological networks in a few minutes of observation. All the photos in this post were taken in the space of seven minutes this morning on my way to work on the same young elder bush.

 Despite the fact that elder, Sambucus nigra, has relatively few insect predators, most likely due to it having cyanogenic chemicals in its leaves, elder aphids are an important link in networks making use of elder sap. 

Ants have a mutualistic relationship with the aphids. They benefit from the aphids honeydew by soliciting them to excrete it, taping them with their antennae. The sugary rich liquid is consumed by the ants and their larvae. The ants treat the aphids as their domestic animals. The aphids benefit too, as potential predators or parasites are pursued or attacked by the ants.

But the ants can't totally defend the aphids from their numerous predators. Here a female hoverfly, Epistrophe eligans, lays eggs on a patch of elder aphids.

A hoverfly egg is visible on the centre of this photo, on the edge of the aphid colony.

See the patches cleared of aphids in this patch? They are due to predation by the green hoverfly larvae just visible amongst them. Surrounded by food, the larvae will gorge on the aphids and grow rapidly.

This hoverfly larvae (possibly Epistrophe eligans) is likely to be ready to pupate.

Not only hoverflies, ladybirds are attracted by this aphid bonanza and adults land on the elder, possibly attracted by the smell of aphids. A Harlequin sunnies itself on a leaf...

...while an active 2 spot searches about.

Ladybirds have laid their bright yellow egg clutches on or under the leaves, near the aphid colonies.

...here visible on the background. I couldn't find any ladybird larvae today on this elder. 

This fly enjoyed licking the honeydew on a leaf. Some species of butterflies, like the Speckled Wood, also takes advantage of honeydew.

Five species (2 ladybirds, a fly, an ant and a hoverfly) thriving on elder aphids. If I had waited a bit longer, or being a bit luckier, I could have witnessed tiny parasitoid wasps that lay their eggs inside the aphids and eat them from the inside!

Overwintering

 BugBlog has been dormant for a few weeks. Somehow, posts somehow never went past the project status. But today, the sun shone after days of rain and gloominess, and in a walk at the park, my 4 year old and I did an informal ladybird survey. We checked many tree trunks and spotted lots of ladybirds, not as many Harlequins as other years, but still the easiest ladybird to find in the park. They were quite active as it was mild, and walked on the tree trunks in the sun. More than 40 in total, as the cluster of Harlequins above nestled in a little hole on a tree trunk was a little tricky to count. A single 2 spot ladybird completed the survey.

Inside curly cherry leaves with their food

Yesterday we gave our cherry tree a light trim, removing shoot tips damaged by the black cherry aphid. The leaves curl up, sheltering hundreds of aphids (above). Inside the leaves, with their prey, there were hundreds of Harlequin larvae larvae, a few 2 spot larvae and with few adults of both species, a 10 spot ladybird and a few predatory hemipteran bugs.

A mirid bug Deraeocoris ruber (I think!)

10 spot ladybird, near a black cherry aphid

Fully grown Harlequin larvae

2 spot ladybird larvae

Two spot ladybird

An unusual 2 spot ladybird with 3 spots!

Ups and downs of ladybirds

I came across a 2 spot ladybird today on the way home (above, being checked by a garden ant). This ladybird species seems to have been the main loser in the Harlequin ladybird invasion, with a 44% decline since the harlequin arrived. They share habitat, and the small size of the 2 spot makes it easy prey of the harlequin when in the larval stage. The future does not bode well for the 2 spot. The same stretch of road where we found the lone 2 spot is a Harlequin hotspot: today there were tens of active harlequins, and we counted not one...

 not two...

 not three...

but five pairs mating.

Lay them and eat them

During the past week, Harlequins have become more noticeable. I spotted a few walking on a tree trunk in my street. Today, passing by the same tree I had a look and saw many clusters of bright yellow-orange eggs laid on small crevices on the tree trunk, they are not wasting time! One of the Harlequins seemed to be laying (above). I also noticed that some egg clusters looked like they had been partially predated. The culprit is not hard to find: Harlequins are known by their cannibalistic tendencies, so - hungry after winter - , they may turn to eat eggs laid by other ladybirds. They also may be able to eat their own unfertilised eggs.

A Harlequin stretching its wings in the sun

A cluster of eggs

Harlequin near cluster with predated eggs

A close up of another cluster. Note the chewed up egg on the top right hand side.

Do spiders find ladybirds distasteful?

 I witnessed a curious interaction today. A 7 spot ladybird was walking up a wall, when a sudden movement caught my eye. It was a large spider, a female Amaurobius similis that had dashed out of her burrow in a hole in the wall, probably alerted by the pull of one of the silk threads that radiate from her burrow. She had caught the ladybird by one leg. The ladybird struggled to free itself, but she need not fight much. After a few moments, the spider released her grip, turned round and retreated into her burrow. The spider obviously had assessed the ladybird and regarded it not suitable for a meal. I doubt it was due to the ladybird size or strength, as Amaurobius are powerful spiders, able to subdue large flying insects such as droneflies and honeybees. The other possibility is that the spider has tasted the alkaloid rich liquid that constitutes ladybirds chemical defence mechanism and that is released from their leg joints when alarmed (the 'blood reflex'). I have previously seen dead ladybirds wrapped on silk caught on the webs of two spider species (garden spiders Araneus diadematus and the false widow Steatoda bipunctata). Indeed, field surveys and experiments carried out by John Sloggett showed that A. diadematus does trap and consume ladybirds, and is apparently immune to the toxic effects of ladybird's chemical defences. In contrast, other spider species do seem to find ladybirds distasteful, so this is a strong possibility for Amaurobius.

Another view of the interaction, not as sharp, but it shows clearly how the spider's chelicerae are pulling and lifting the ladybird's front right leg.

For other spiders, however, ladybirds are not even considered a food item. Take this little wolf spider, enjoying the company of the 7 spot ladybird a few days ago. Both individuals were sunbathing next to each other most of the morning. The spider popped in and out, paying no attention whatsoever to the ladybird.

More information

Sloggett, J. (2010). Predation of ladybird beetles by the orb-web spider Araneus diadematus BioControl, 55 (5), 631-638 DOI: 10.1007/s10526-010-9291-0

Pine ladybirds waking up

 We spotted lots of Pine Ladybirds, Exochomus quadripustulatus, in our street today. They were crawling on tree trunks on the sunny side of the street, a couple of pairs mating, some still in a little group overwintering together and others just stretching their legs. They used to live mostly near pine trees, willows and sallows, but pine trees are very scarce in our area and I haven't seen any in our street. I assume in our street they feed mainly on scale insects, in particular the Chestnut Scale insect, Pulvinaria regalis, which feeds on trees, including Lime and Sycamore, producing occasionally heavy infestations. Some colour forms of the Harlequin can be similar to the Pine Ladybird, but there are always white marks on the Harlequin pronotum, while the Pine ladybird is all black, with 2 or 4 red spots, the frontal ones with a characteristic comma shape. Pine ladybirds are also smaller, 3-4 mm, and have a rim in their elythra reminiscent of a bowler hat as you can see in the photo below.

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.

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?