The Garden Diary 2009

Pseudopsocus rostocki

Autumn Observations
18 September - 25 November

Part 1

Warning - Work in progress!  Portions of the test have been copied from the garden diary and make well contain numerous mistakes at the moment. Once the most drastic mistakes are corrected this page will be split into two or three smaller parts. I will be completing these tasks before I add the picture links.

An introduction

Having a son who runs a tree surgery business seemed too good an opportunity to waste, and a couple of years ago we installed a log burner. As well as the burner a log store was needed, and dealing with the logs for that in effect introduced me to the barkflies, a group of insects that I had largely ignored until then.

Since then I have found some fourteen species here, either on the logs or on trees and shrubs in the garden. While the garden plants have been a source of the more common species, such as Valenzuela flavidus, the logs have been a much more interesting source, with both common and uncommon species appearing. And it is not just fresh timber that is worth checking. I find that seasoned logs often have thriving 'colonies' of Peripsocus milleri, for example. With that in mind I try to ensure that as timber is used up, some 'old' logs that are inhabited are replaced in amongst younger timber in an effort to maintain the barkfly presence.

Just occasionally a new supply of logs delivers a surprise, as happened at the beginning of November 2008.

On the 8th I was sorting out some logs for the burner and as usual took time to check them. I had already found and photographed a Pteroxanium kelloggi, and then I spotted this quite active individual on a piece half-seasoned oak.

It had me puzzled and I wasn't able to match it with any of the illustrations on the NBRS website, and my Barkfly handbook (T R New) didn't help. Fortunately, the next morning I had an e-mail from Bob Saville, identifying it as Pseudopsocus rostocki.

Unfortunately, as the batch of timber came from more than one oak tree, my son wasn't able to pinpoint the exact location of where the log originated, apart from it being within 5 miles of his home in Farnborough, Hampshire.


I was able to photograph rostocki feeding on lichen. Thanks to Bob's contacts that has been identified as Melanelixia subaurifera (syn. Parmelia subaurifera, Melanelia suburifera). It appears to be concentrating on the upper cortex and algal layer of the lichen's thallus.

After a few days I returned the log to a 'safe' part of the log store and when I rechecked the log it had disappeared.


September 2009



On 16 September My son let me know that during the previous few days he had felled two oak trees in a dangerous condition in a garden in Mytchett (SU889550) near Aldershot, and had brought the timber back to his property. On the 17th I collected some logs to inspect and found not one but five P. rostocki.



A few days later I collected some more logs and found another individual. This one was feeding on a blue-green foliose lichen that I have not yet identified, although for much of the time it remained in a silk shelter in a crack in the bark

This log was not added to the log pile but kept on my veranda so that I could keep a watch on it.


October 2009

3 October - I had been monitoring the activites of a fox at the bottom of our garden during September, but when it stopped using a sheltered corner of the garden as a temporary den I was able to organise a cctv camera to assist with the monitoring of the log with rostocki on it. This started on 3 October. The camera was linked to a hard drive timelapse recorder.

The arrangement was set up on our veranda under a canvas canopy. To ensure that the bark didn't dry out I decided to treat the log with  a fine mist spray of rain water each day,


Something that has puzzled me about P. rostocki has been the lack of faecal pellets in and around its shelter. With most of the barkflies I've seen here, the presence of these pellets has been a helpful indicator of their presence. This absence of pellets was certainly the case with the individual that I had started to monitor.

When the recording started at 8am the barkfly was just a couple of centimetres away from its silk shelter, and was feeding on algae. That session lasted some twenty minutes before it returned to the shelter down in a wide crack in the bark. Once there it stayed for the next four hours.

Something that has puzzled me about P. rostocki has been the lack of faecal pellets in and around its shelter. With most of the barkflies I've seen here, the presence of these pellets has been a helpful indicator of their presence.

Anyway, that mystery was solved when at 2.15pm the barkfly started moving about, climbed up out of its shelter and turned so that its rear end pointed away from it. A faecal sac was produced. When most of the pellet had emerged there was a pause for a moment or two,  and then instead of simple dropping to the surface it was projected away from the abdomen at high speed, and out of the image frame, too fast for the video setup to record at 25 frames per second. That done, it headed back into the shelter and spent a few minutes grazing on the algae at the side of the crack. I can't help likening the process to a toy pop-gun, with the cork poised at the end of the barrel until you press the trigger!

It was 6pm before it left again, projecting another pellet before going a couple of centimetres away to graze. Another pellet was projected while it ate.

After that it returned to the shelter

4 October - At 2.13am  it left just after another (unidentified) barkfly came close to the shelter. Rostocki wandered about, grazed just a bit and returned to the shelter where it remained active for about twenty minutes.

At 7.37am it once again emerged, reversed away from the shelter and produced a pellet before starting to feed. This time the pellet seemed to get caught up on a silk thread. The barkfly was back under the silk by 8.25am, and stayed there all morning.

It was 1.33pm before it emerged again to project another pellet at least four body lengths away. It retired into the shelter immediately but grazed on the algae in there for a minute or so before becoming still again.

At around 4pm an E. petersi arrived in the area and started grazing. It may have disturbed rostocki which became active down in the crack. Ten minutes later it climbed out of the crack and started wandering in the area around the shelter much more than previously, but not grazing, and I didn't see any faecal pellets produced. When it returned under the silk at 4.26pm it did appear to graze then.

From around 4.50pm an E. petersi appeared frequently in the small area covered by the camera.

At 5.55pm rostocki decided to leave once more, and this time immediately headed away from the shelter and out of the camera's field of view. It has not returned all evening (it is 10.30pm as I write this).

I did not attempted to find it that night. Instead, I left the camera running all night in case it returned.

When I reviewed the recording the next morning there was no sign of rostocki in the small area being monitored (appr. 23x47mm). The log had a great deal of cover under which it could have been hiding, and I wasn't able to find it again when I checked it over the next few days.


12 October - Subsequently I found yet another individual, although the monitoring didn't get off to a good start when it too wandered out of view and disappeared.

However, it reappeared on 12 October, having created a shelter for itself at the end of a crack in the bark of another oak log.

That evening it didn't leave the shelter despite a period of activity between 8.50-9.45pm.


13 October - It was active again between 2.35-2.50am. It first left the shelter at 4.47am when it went less than a centimetre away to feed before returning to the shelter at 5.41am, remaining active for the next 45 minutes.


Once it settled down at around 6.25am it remained more or less motionless for the rest of the morning.

That state continued even when this insect larva decided to graze just a couple of millimetres away ( remember, rostocki is just 2mm long).


At 2.38pm it reversed out of the shelter and produced a faecal sac. Unfortunately the image was too out of focus to tell if the pellet was projected as described previously. Once under the silk again it kept still until around 4.45pm when it became active again. It left the shelter at 4.50pm and spent a short time wandering over the small area covered by the camera before starting to graze for the next 35 minutes. When it finished it returned to the shelter where it appeared to work on the silk for nearly half an hour before settling again.

It left again at 9.46pm for a very brief excursion, and then spent a bit more time working on the silk canopy before settling again.

During the afternoon I decided to reorganise the monitoring set-up. Up until then the camera had been mounted on a tripod. As well as taking up space on the veranda and being easily bumped accidentally, it also meant that every time someone walked across the veranda the vibrations caused played havoc with the image. Now, the camera is mounted on a focusing rail on a tripod head that is bolted to a small steel framed table. With the log also on the table the vibration problems are  more or less cured. Also, the log is now standing on end ( as it could well have been on the tree).

Overnight illumination is now provided by a red heat lamp, connected through a dimmer to give a very low level of red light.


14 October -


Last night, rostocki headed out to feed at 12.56am. This session lasted some forty minutes before it settled under the silk once more.


The blue tint in this image is produced by the LED light bulb I'm using for this exercise.





At 9. 52am there was another potentially disturbing moment when another barkfly (poss C. questfalica) arrived just above the crack, although it turned away and rostocki didn't flinch. During the rest of the morning there was only a short, five minute period of activity.

And things stayed quiet until late afternoon.



Then, at 4.45pm there was activity under the silk before rostocki climbed out at 4.54pm and headed off to graze.

To put that into some perspective, while it is difficult to be precise in a situation like this, at the plane of focus (where objects appear sharpest in the image) the camera lens covers an area of around 10x13.5mm. At no time today has rostocki ventured beyond these limits, although I have now rotated the camera slightly to cover more of the area covered by algae to the right of the shelter.


Rostocki returned to its shelter at 5.30pm and hasn't moved since - at least, until 8.45pm (which is the time as I write this.

Something I haven't seen this time is a clear image of the projectile defecation that I witnessed with the previous rostocki. However, with the more stable camera arrangement now in place, I hope to be monitoring it for a while (as long as it doesn't decide to leave, as the first one did!).


15 October - A day which started with hazy sunshine but which became cloudy in the afternoon.

The barkfly saga continues, with a slight distraction today -

Following yesterday's report rostocki didn't move again until 3.07am when it climbed out of the shelter and out of the frame. It reappeared after 17 minutes and spent the next twenty minutes or so grazing on the algae next to the shelter.

About 18 minutes into that session there was an intrusion into the frame by a leg which settled. Despite this, rostocki continued to eat for another two minutes before returning to its shelter.




When daylight arrived the leg was still visible, having moved slightly, but rostocki ignored it when going out for a feeding session between 8.24-9.01am.





Both creatures were still in place when I recorded this image in the late afternoon.




And what did the leg belong to?  - A harvestman. An initial search suggests that it is  Leiobunum rotunum, an abundant species. Like all harvestmen it will prey on small insects, so perhaps rostocki was taking a chance in moving about below the leg!

In this picture I've highlighted the approximate area covered by the cctv camera to give an idea of its size. Its body is just over 5mm long and the longest legs must each be the best part of 6cm in length - it's a giant compared with rostocki, whose hiding place is indicated by the red arrow.


The book I'm looking at ('The Natural History of the Garden' by Michael Chinery) suggests that it is a species that is an active hunter by day and by night, although this one didn't move from the time it arrived at 3.47am and when I accidentally disturbed it while trying to measure it at around 4.30pm.

At 4.40pm rostocki climbed out of the shelter, turned around and produced a faecal pellet (as far as I can tell, for the first time today). Unfortunately, its rear end was over a dark background and even with the timelapse recorder recording at 50 frames per second I couldn't make out whether or not the pellet was projected.

At 5.23pm it suddenly decided to leave the shelter again, this time heading going down the log and out of sight of the camera for the next 23 minutes. On its return it headed straight back into the shelter and settled immediately. So far today I haven't seen any substantial activity inside the shelter. After dusk it moved deeper into the back of the shelter so that it became hidden from view for the first time.


16 October - A grey, although quite bright morning. Last night the temperature low was 10C and as we approach mid-day it has only risen by 3 degrees.

Rostocki continues to grab my attention. Having done very little in its shelter during the day yesterday, at 10pm it started 'working' busily, and at 10.45pm I'm almost certain that it laid an egg.

It is difficult to show in pictures, but I have captured a sequence of images to illustrate what we saw (Sheila has agreed that it must have been laying an egg).

First, rostocki emerged from the upper, hidden part of the shelter and paused, facing downwards. A short time later a shiny (moist?) object emerged from the rear of her abdomen - certainly too big for a faecal pellet (also, these are never shiny).

Then she seemed to place the object against the surface, and as she waited the shine slowly disappeared, presumably as the surface of the egg dried out.


Rostocki eggs are black, making it difficult to see in the shadowy situation that exists here. I don't want to risk disturbing her, so I am resisting temptation to start shining a bright light onto the area.

I've now replaced the colour camera with a black and white camera and I will add some infra-red lighting before this evening. However, at the moment, even this camera isn't producing an image that safely confirms the presence of the egg.



Anyway, after that event had occurred, activity in the shelter continued fOR another ten minutes before she left at 10.55pm. She climbed up the log and disappeared from view for around five minutes, arriving back in the shelter just after 11pm.

She left again at 1.52am, this time disappearing downwards and not returning from this excursion for 41 minutes.


At 8.20am she emerged just briefly to produce a faecal pellet, which I think was projected away as described previously.

As usual, she climbed out of the shelter and turned around before producing the pellet.



Once it had emerged, it remained attached to the end of her abdomen for another ten seconds before it suddenly disappeared.

The two images shown here were captured 1/50sec apart, and there is no sign of the pellet in the second image. With the barkfly perched on a vertical surface, if the pellet had just fallen away I would have expected to see at least a blurred image of it in a subsequent frame, but I cannot see any signs of it at all. I think I need one of those high speed cameras to finally solve this one!

After returning under the silk canopy she did not move from her resting position in the shelter all morning. There was no further activity until she left again briefly to project another feacal pellet at 5.22pm. The evening saw no activity by her.


17 October - Another dry day with some sunshine but a high temperature of just 11C after an overnight low of around 7C on our veranda.

Perhaps it reflects the colder night, but rostocki was not active during the night, apart from a bit of movement within the shelter at 10.52pm. Its first trip out today was at 6am when it left just long enough to produce a faecal pellet. At 7.43am it left again. This time it headed down the log and disappeared for the next 52 minutes during which time I must assume it was feeding.


Once it returned from that outing it stayed put in the shelter for the rest of the day, until 5.49pm when it again climbed out to produce a faecal pellet.

This followed the usual pattern as rostocki climbed out and then turned to face the shelter.




Then it raised its rear end and a pellet was produced which remained attached to the abdomen for a short time (nearly 5 sec this time) before it disappeared.

Again, analysis of the frames gives no indication of where the pellet travels to once it has been projected. If you look at the large images I have included the three full frame images  around the moment when the pellet disappears. The dark area below the barkfly is under an overhang and it is very unlikely that the pellet could have gone there.


The cctv image includes an area of about 11.5x9.5mm, and in this sequence of images the rear of rostocki is about 5mm from the right edge of the frame. If my observations and calculations are correct that would mean that the pellet is projected at a speed of at least 25cm/sec!

Rostocki didn't leave again today, but at 8.47pm it started working on the shelter canopy, adding more silk towards the lower end. This activity came to an end at 9.33pm, and Rostocki settled down for the night.



18 October - A brief entry - A dry day, and after a chilly night with a low of 3C the temperature got up to 13C in the afternoon.

At 3.20am rostocki spent about 10 minutes moving about in the shelter but then became still again until she appeared to get ready to leave at 7.50am. She waited until 9.10am before she actually left, heading down out of of view. This outing lasted 50 minutes and she was settled back in the shelter at 10am.

It wasn't until 6.10pm that she became active once more, climbing out of the shelter and once again appeared to be adding more silk, this time to the left of the shelter. She re-entered the shelter after six minutes but continued to work in there until 6.30pm.

At 10.56pm she emerged just long enough to produce a faecal pellet (projected away as usual), and by 10.59pm she had settled down at the back (top) of the shelter.



19 October - A day that started with just a touch of dampness in the air but which became brighter with some sunshine in the afternoon. Last night's low was 7C and this afternoon on the veranda it reached 14C.

The rostocki saga continues - The only activity noted during the night was her moving about inside the shelter between 12.11-12.20am.

Her first trip out came at 7.55am when she once again disappeared out of view (down-right this time) and returned 47 minutes later. I must assume that these long trips are to feed, although I have no way of confirming this. I have repositioned the camera to include a larger field of view to try and establish where she goes. As soon as I have established where she is going I will return the camera to its closer view of the shelter

After the morning trip she remained more or less stationary in the shelter all day and all evening, apart from leaving the shelter briefly at 4.42pm to produce a faecal pellet, and a bit of 'low intensity' activity within the shelter between 6.16-6.50pm.

Tearing myself away from rostocki for a moment, other things are going on in the garden. I've been taking advantage of the dry weather to do bits of woodwork and associated painting, and this afternoon I did some long overdue gardening tasks, including clearing the area under the Birch and alongside the paths.




20 October - A day that started dry, but rain arrived by lunchtime. Last night there was a low of 10C, although the temperature dipped 8C during the first part of the morning. This afternoon the temperature rose to around 14C.

Last night was a quiet one for rostocki with no activity beyond a couple of position adjustments until she started to move about at 8.12am. At 8.19am she headed out and down right, pausing just outside the shelter when she appeared to be preparing to defecate. However, I didn't see a pellet produced and she was soon disappearing out of view (I had enlarged the camera's field of view, but not enough!). When I noticed that she had gone I went outside to try and spot her. However, while I didn't see her I suspect that my presence may have disturbed her as she was back in the shelter by the time I returned indoors at 8.38am.

Shortly afterwards I adjusted the camera to include a larger area in the image.

At 10.55am rostocki became active in the shelter for a prolonged period (until around noon).

She started again just after 1pm and this time appeared to be adding more silk at the lower end. Unfortunately, the field of view now provided, at about 24x31mm, means that rostocki appears too small to be sure of what she was doing. There was a further, similar session between 1.42-2.35pm before she became quiet for the rest of the afternoon.


At 5pm she started to move again and at 5.04pm she left the shelter and started heading down-right once more.

A short way along, she turned around to face the shelter and paused to produce a faecal pellet (successfully this time!).

Then she turned down-right once more and headed for a foliose lichen that was just in view at the corner of the frame.



She spent nearly 20 minutes feeding on the upper surface of the lichen before heading back to the shelter at 5.27pm.

This time she didn't react as I reset the camera to get closer images. Once she was back 'home' the camera was set back to the wide view.



21 October - A dry, although cloudy day. Last night the temperature dropped to 8C on the veranda and reached a high of 16C this afternoon.

After feeding at the end of the afternoon yesterday, rostocki remained inactive until just after midnight. at 12.29am she left the shelter, paused to defecate, and then headed down to the lichen again, and arrived there at 12.33am. This time it didn't climb onto the lichen but nibbled along the left-hand edge. It finished its meal at 12.49am and had returned to its shelter by 12.44am.

At 5.02am it became active within the shelter for the next forty minutes.

At 7.19am it left once again to feed at the left side of the lichen. With a long pause outside the shelter it over five minutes to meander slowly to the lichen, although it didn't defecate during the journey this time. It stopped feeding at 8.01am and returned to the shelter just a minute later.

There was no activity seen between then and its next emergence came at 3.27pm when it produced a faecal pellet (back in shelter within two minutes).

At 5.38pm it set out to feed for the third time today. I was surprised to see it stop to defecate again before arriving at the lichen at 5.40pm.



This time it chose a completely different part. As the picture indicates, it spent the whole session with its head tucked under the right hand side of the lichen.

I wondered what effect my camera getting in close to take this photograph would have on rostocki, but I needn't have worried as it continued to feed for more than five minutes afterwards before it returned to its shelter at 5.55pm.



After the barkfly was settled in the shelter again I took another photograph of the part of the lichen that it grazed on yesterday afternoon.

Looking back at yesterday's recording, the light areas were where the grazing took place, although the infrared image makes it difficult to tell how much of the surface had already been eaten away previously.


In some ways the photograph may pose more questions than it answers. Here I've cropped the image and adjusted it to emphasise variations.

For example, notice how the some of the grazed area edges are lined with algae. Has this developed since yesterday, or was it this that rostocki was feeding on? During yesterday's feeding session rostocki appeared to move between all the light areas, visiting the area at bottom-right only briefly before leaving.



22 October - After a quite mild night (min 11C) there was a bit of rain before I got up this morning, but the rest of the morning has been dry with some sunny spells (14C on the veranda just before noon, and just a degree higher during the afternoon)

Rostocki's day started at 12.20am when it popped out to defecate. At 2.48am it left the shelter again, this time heading for the lichen. It stopped en route to produced another faecal pellet before going not to the 'leafy' part of the lichen but the black debris to the lower left of it. It finished feeding at 3.12am and returned to the shelter a minute later.

It was out to feed again at 7.28am and took five minutes to meander its way to the lichen, although no pellet was produced during the journey. It fed first at the left edge of the lichen before moving on to the black material. This meal was completed at 8.06am and again it took less than a minute to return to the shelter.

I needed to delve into one of my old Botany textbooks to remind myself that the black structures are in fact rhizinae (or rhizines) which are extensions of the underside of the lichen's leaf-like thallus (the lower surface of this is called the hypothallus). The rhizines are made up entirely of fungal hyphae and adhere the lichen to the bark (or other substrates, such as rocks). I understand that they also have the important function of absorbing water. This is then transported up through veins to the algae in the thallus where it is needed for photosynthesis.


Once I saw that rostocki had settled again I went out (as I do at some point each day) to spray the log with a mist of rainwater. Afterward doing this, it's interesting to fast-forward the cctv footage to give a time-lapse sequence of what happens.

The first image shows the lichen before water is sprayed.

On the second image you can make out the water droplets as spraying takes place (it appears darker because I had to move a lighting reflector).

The third image, recorded shortly afterwards shows that the droplets have either spread out, or have started to be absorbed. The lichen itself had drooped slightly.

The final image, shows how the leafy part of the lichen has swollen and become more erect over the next fifteen minutes as a result of absorbing the rain water.

Getting back to rostocki, it left the shelter briefly at 2.45pm the produce a faecal pellet. I have yet to establish just how far they travel when they are projected!

At 4.33pm an extended period of activity began during which rostocki left the shelter twice in the direction of the area of algae to the right. It appeared to be extending the network of silk, but with the camera view as wide as it is it was difficult to be sure of this. A couple of times it stopped to nibble but there was no prolonged feeding. It was back in the shelter and settled by 5.34pm.


23 October - A largely sunny day with the temperature on the veranda getting up to 17C after an overnight low of 7C.

A quiet day for rostocki with it feeding just once. It left briefly at 2.30am to defecate and then left the shelter again at 5.42am to arrive at the lichen four minutes later. This time it started off in the black, rhizine debris but also spent a short time on the thallus itself before returning to the shelter at 6.30am.

During the rest of the day it left the shelter just one more time, to defecate again, and at 4pm it became active within the shelter for around forty minutes.

At 10pm she left the shelter as though she was going to produce another faecal pellet, but once again she didn't appear to do so and returned to the shelter.


24 October - A day that saw a mixture of sunshine, somewhat blustery showers and periods of drizzle. An overnight low of 10C was followed by a high of 18C during the afternoon.

Rostocki's day started soon after midnight, although she had already positioned herself by the exit at 12.50pm. She left the shelter at eight minutes after midnight, headed down to the lichen, and spent 25 minutes feeding before getting back to the shelter at 12.37am.

She visited the lichen again before dawn, leaving the shelter at 4.47am and meandering down this time, taking over five minutes to get to the lichen. Once there she spent most of her time amongst the black rhizines, spending just a short time on the thallus before ending the meal at 5.06am and taking less than a minute to return 'home'.

She was active within the shelter between 9.40-9.45am.


At 11.42am she left the shelter once again, defecated (pellet clearly projected), and then went on to feed once again.

At one point I could see her grazing on algae on the bark itself, to one side of the lichen, although it had climbed onto the thallus by the time I captured this picture, probably the clearest shot I've managed yet of a Pseudopsocus rostocki.

It returned to the shelter at noon.


After a nine minute pause she embarked on a series of active periods within the shelter, from 12.09-12.45pm, 1.00-1.30pm, and 2.22-2.28pm. Again, the camera is too far away to see what she was doing, although I think that for a bit of the time she was adding silk to the canopy. At 4.41pm she left briefly to defecate again.

At 5.15pm she moved to the exit, and after a long pause she headed directly to the lichen for the forth time today. This time she spent the whole session under the thallus, finishing at 5.37pm and getting back to the shelter within a minute (as usual, the journey home was much quicker that the journey out).

While I have been monitoring rostocki (since 3 October) it appears to have had a very 'laid back' existence, just popping out for its shelter to feed and defecate, and it hasn't been disturbed by other creatures. However, live for barkflies isn't without its perils.

At 9.51am two small creatures suddenly appeared at the top of the image - a barkfly nymph followed very closely by a mite. While they were close to the limit of the camera resolution, I have extracted this sequence.

The nymph was clearly trying to escape the mite which seemed to have hold of its rear end. When the nymph stopped, the mite dashed to its side and started to suck up its bodily fluids. Over the next ten minutes or so the mite moved around its victim to feed on other areas of its body

In the last but one image of the sequence you can see how much the appearance of the nymph has changed.

The mite finally moved away and out of sight at 10.28am.


If you click on the composite image to see the larger version I have also included some of the individual images which, while still of low quality, show the mite and nymph more clearly.



25 October - Last night's low was 11C. For most of today we had blue skies and sunshine, which brought us a high of 18C on the veranda, although the afternoon ended and dusk approached with showers. Dusk came an hour earlier today since the clocks changed from British Summer Time to Greenwich Mean Time during the night.

The first timing for rostocki is in BST - she left the shelter to produce a faecal pellet at 10.34pm.

At 12.13am (BST) she started a period of quite vigorous activity which included work on the silk canopy and extended out a short way. She finally settled again just over 50 minutes later at 12.04am (GMT).

From now on all timings are GMT -

At 3.14am she left briefly to defecate but I didn't see a pellet produced. At 6.25am she left the shelter again, and two minutes later arrived at the lichen. She spent this feeding session on top of the lichen thallus, leaving at 6.58am and taking just a minute to return to the shelter.

The only other activity during the day was her leaving for just a minute to defecate at 4.04pm. It produced another pellet at 5.56pm.

At 10pm an extended period of activity began. For the first hour it was confined to the shelter, but after 11pm it extended out to the right and down a bit more, until rostocki returned to its shelter quickly when a earwig appeared at the right edge of the image.

No photographs today, but looking out of the window this morning I noticed that the dozen Goldfinches that were at the feeders had been joined by the first Greenfinch that I've seen in the garden since March.


26 October - A low of 11C last night followed by a high of 17C today.

At 3am rostocki left the shelter and disappeared below the edge of the image frame. At 3.48am it reappeared at the lichen where it fed under the thallus, on the log to the right of it, and finally had a quick nibble on the thallus itself before heading back to the shelter at 4.02am.

It returned to the lichen at 7.02am. This time it grazed at the edge of the thallus before spending time on the top. That meal was completed at 7.38am and it was back in the shelter a minute later.

Rostocki didn't feed again today, but left the shelter to defecate at 11.25am, 4.51pm and 11.27pm.

A earwig appeared again at 5.52pm and 5.52pm.


27 October - A low of 12C last night and a high of 19C on the veranda today - quite remarkable temperatures as we approach the end of October.

The predatory mite was about again today, making its first appearance at 1.42am as it searched other parts of the visible area but stayed away from rostocki's shelter.

Rostocki's first activity of the day was to defecate at 2.24am. At 4.33am it left the shelter briefly during a short period of activity to produce another pellet.

At 6.36am the mite appeared again and this time got within millimetres of the shelter. Rostocki didn't respond then, but three minutes later it left the shelter. This didn't seem to be in response to the mite's visit as it meandered down to the lichen. It started to feed but when the mite arrived again it headed out of frame. After a few minutes it returned to the lichen and continued to feed until it left at 7.05am to return to the shelter a minute later.

At 7.42am it headed back down to the lichen and grazed on the edges and top until 8.09am. As usual it took a minute to return to the shelter.

After that there was a long period of inactivity apart form about five minutes activity in the shelter at 2pm and a two minute trip out to defecate. At 5.04pm rostocki started on another long period of activity, this time strictly within the shelter, and which ended at 6pm.

There was no further activity before midnight.


28 October - An overnight low of 11C and a high of 19C during the day as the mild spell continues, and it was dry.

At 12.31am and 5.03am rostocki left briefly to defecate. At 6.47am it left to feed on the lichen, and on the log to the right of it. That meal ended at 7.35am and it arrived back at the shelter a minute later.

After that there was no further action until a very small barkfly nymph appeared by the lichen at 4.25pm and spent half an hour grazing on the the bark surface to the left of it. At 5pm rostocki became active for just over an hour, although it remained completely within the shelter.

Its only other activity today was when it left the shelter briefly at 11.10pm. Once again it looked as though it was going to defecate, but I don't think it did.


29 October - A marginally cooler day with a high of 18C after an overnight low of 10C - still dry and bright!

Rostocki started the day by leaving the shelter briefly at 12.35am to defecate. It was 6.44am when it was next active, meandering to the lichen and grazing at the top edge of the thallus. However, at 6.59am it was dusturbed when the predatory mite appeared and it headed directly back to its shelter.

The mite didn't attempt to catch rostocki but did catch and feed on a small barkfly nymph, the incident taking place largely out of sight under the lichen thallus.

The mite was still under the lichen when rostocki left the shelter once again and returned to the lichen to continue its meal. Disturbed by the mite again, this time it disappeared down below the image frame. When it did reappear aT 7.47am it undertook a period of intense feeding before heading back to the shelter at 7.55am. The mite remained active in the area until 8.15am.

It was 4.33pm when rostocki undertook a short period of activity in the shelter and left just to defecate at 5pm. Another five minutes of activity took place at 5.50pm.

During the afternoon there were several periods of activity by small barkfly nymphs. This levle of activity hasn't been seen since I started this monitoring of rostocki. And at 6.41pm a wingless barkfly (nymph?) that was as large as rostocki appeared briefly for the first time.

At 11.55pm Rotocki left the shelter briefly to defecate.


30 October - Overnight low of 11C and a high of 17C.

2.35am - left shelter to defecate
3-6am  - a great deal of (small) barkfly nymph activity at bottom of frame.

6.35am - Departed shelter and meandered to lichen. Fed along top edge of thallus before grazing on the top surface itself. Meal finished at 7.02am and back in shelter 7.03am.

7.15am - left shelter to defecate

9.20am - left to feed again. Arrived at lichen at 9.23am, finished meal at 9.53am and back in shelter a minute later.

3.48pm - left shelter to defecate

5.40pm - active within shelter until

5.50pm - it left the shelter and wandered out of frame briefly, being back in the shelter by 5.52pm.

11.16pm - left shelter to defecate.


31 October - Overnight low was 12C and the day's high was 19C.

2.08am - left to feed

2.09am  - defecated en-route

2.10am  - started feeding at edge of thallus;2.20am left lichen and returned to shelter by 2.21am

6.54am - left to feed again. Arrived at lichen at 6.56am; fed on top of thallus until 7.27am; back in shelter at 7.28am.

3.35pm - left shelter to defecate

4.38pm - activity in shelter until 5.10pm

8.27pm - left shelter to defecate


November 2009

1 November - overnight low of 9C, day's high 13C

6.50am - left to feed; arrived at underside of lichen at 6.51am; fed there before moving to top of thallus until 7.40am; returned to shelter at 7.45am.

4pm activity in shelter until 5.20pm; and again 6.15pm - 6.40pm, 8.55-9.10pm


2 November - Overnight low 7C, daytime high 13C

1.48am - Activity inside shelter until 2.40am

7.20am - left shelter to feed on top of lichen thallus from 7.28am until 8.15am; back in shelter at 8.17am.

4.26 - 4.52pm - active inside shelter, although it left shelter briefly and seemed to be adding silk around 6.31pm; no sign of defecation taking place.

11pm - left shelter to defecate.


3 November - Low 7C, high 14C

5.12am - left shelter to defecate

7.07am - left to feed at lichen from 7.11-7.55am; grazed along top edge and then top surface of thallus; back in shelter at 7.56am

4.35pm - left to feed again; at lichen from 4.39-4.56pm; back in shelter at 4.57pm but remained active until 5.35pm

6.03-6.20pm - further activity within shelter

6.55pm - a hunting spider approached but seemed to hesitate as soon as it encountered the silk threads below shelter and left the area.

10.50-11.05pm activity inside shelter


4 November - Overnight low 8C, high 13C

5.57am - left shelter to defecate

7.27am - left to feed,; arrived at lichen at 7.29am; out of sight under right side of thallus until 8.41am; back in shelter at 8.43am.

4.21pm - left shelter to defecate

6.42-7.42pm active within shelter.


5 November - Overnight low 9C, high 13C

7.20am - left to feed; arrived at lichen at 7.26am; grazed on top of thallus until 8.13am; back in shelter at 8.15am

3.20pm - left shelter to defecate

4.17-4.49pm - active inside shelter


6 November - Overnight low 9C, high 13C

12.58am - worked on silk outside shelter before defecating; back inside shelter at 1.01am

8.01am - left to feed, although it spent some time working on silk outside shelter before heading for the lichen; Fed from 8.06-8.54am, some of this time spent hidden behind the thallus; back in shelter at 8.57am

3.37pm - left to feed again; fed under thallus between 3.41-4.10pm; back in shelter at 4.11pm.


7 November - Overnight low 6C, high 12C

3.29am - left shelter to defecate

7.14am - left to feed; defecated en-route; at lichen from 7.21-8.55am (stopped feeding briefly at 8.16am); back in shelter at 8.56am

4.52pm - defecated

6-8.15pm - left shelter to defecate


During the day I replaced the colour camera with a black/white camera, and the red lamp with an array of 48 infra-red LEDs. These emit IR light at a wavelength of 940nm, so that they are completely invisible to the human eye.

This picture shows the arrangement, with the LED array to the left of the camera and a reflector on the long arm to the right. The yellow rectangle shows approximately the area on the log covered by the camera.




8 November - Overnight low 4C, high 10C

5am - Other barkfly (nymph) activity at lichen

7.20am - Left shelter to feed on top of and then under lichen (7.30-8.16am); back in shelter at 8.18am

3.41pm - Left shelter, defecated and then meandered to lichen; fed (3.45-4.26pm) on upper surface of thallus and then underneath it;  back in shelter 4.28pm.


9 November - Overnight low 3C, high 8C

7.20am - defecated without leaving shelter (rear of abdomen pointed out through an 'exit'.

10.19am - Left shelter; defecated; arrived at lichen 10.28am; grazed under thallus until 11.07am; back in shelter at 11.11am

3.50pm - 3.55pm activity in shelter, may have defecated without leaving shelter again.


10 November - Overnight low 5C, high 9C

8.06am - left shelter and defecated before meandering to lichen, arriving at 8.18am; fed under thallus until 9.19am; back in shelter by 9.22am

2.15pm - left shelter to defecate

4.14-4.20 and 5-7pm - activity inside shelter.


11 November - Overnight low 5C, high 11C

7.53am - moved to 'exit' of shelter

8.12-8.15am - grazed near shelter before heading to lichen; fed on top of thallus between 8.18-9.22am; back in shelter at 9.25am

9.16pm left shelter to defecate.


12 November - Overnight low 9C, high 12C

5.45am - started to move about in shelter, although only occasional position changes seen.

7.52am - Started heading out of shelter, but paused at 'exit' for ten minutes

8.03am - left shelter at 8.03am grazed on top of lichen thallus from 8.05am until it was disturbed by a barkfly nymph and left the lichen at 9.03am.; back in shelter at 9.06am

5.55pm - worked on silk around lower 'exit' of shelter before wandering to the right briefly; back in shelter by 6.01pm; continued work on silk for a few more minutes.


13 November - Overnight low 9C, high 14C

8.14am - left shelter to defecate

8.19am - left to feed; at lichen from 8.19am until disturbed by springtail at 8.30am; back in shelter at 8.31am.

10.15am - Left lichen to feed again between 10.17-10.51am, favouring the left edge of the thallus; back in shelter at 10.54am.

4.50pm - activity in shelter until 6.50-6.55pm when it worked on silk at lower end of shelter

8.29 - 9.15pm - further activity inside shelter.


14 November - Overnight low 10C, high 14C

7.40am - moved to exit; paused until it left at 7.58am; defecated en-route to lichen. Grazed from 8.03-9.12am; back in shelter at 9.14am

11.11-11.32am - activity within shelter; and again at 11.58-12.27am, 12.46-1.20pm, 3.10-3.20pm

4.03pm - left shelter to defecate


15 November - Overnight low 8C, high 14C

8.55am - moved to exit

8.58am - left shelter; defecated; headed for lichen; grazed from 9.06-10.02am; back in shelter at 10.04am

10.35pm left shelter to defecate


16 November - Overnight low 8C, high 13C

2.15am-4.30am activity inside shelter; and again 5.15-5.50am, 8.35-9.11am

A technical problem meant that there was no monitoring between 9.50-11.25am

No further activity seen today


17 November - Overnight low 8C, high 14C

Further technical problems meant that there are no records for today, up until 9pm. There was no activity seen between 9pm and midnight.


18 November - Overnight low 11C, high 14C

12.10am - left shelter to defecate

2.35-3.35am - activity inside shelter, and again at 4.15-5am

9.26am  - left shelter to feed at lichen (9.29-10.14am); back in shelter at 10.15am

4.27-4.50pm activity within shelter


19 November - Overnight low 11C, high 15C

12.30am - left shelter to defecate

7.50am - left shelter; defecate at 7.52am; arrived at lichen at 7.53am; grazed until 8.34am; back in shelter at 8.36am

2.32-2.50pm activity inside shelter

3.39-4.25pm - activity inside shelter

4.37pm - left to defecate -  this time the pellet was 'captured' by a strand of silk, only the second time that I have seen a pellet not projected out of the image frame; activity continued inside shelter until 4.50pm.

9.08-9.46pm more activity inside shelter


20 November - Overnight low 10C, high 15C

3.04-4.03am - Activity inside shelter

7.40am - left to feed at lichen (7.44-8.24am); back in shelter at 8.25am

4.39pm - left to defecate

11.15-1120pm - activity inside shelter


21 November - Overnight low 9C, high 15C

4.58-5.10am - activity inside shelter; the activity continued with pauses until

7.44am - left shelter to feed at lichen; returned to shelter at 8.25am

11.45am-2.15pm - activity inside shelter

4.37pm - left shelter to defecate

7-9pm - activity inside shelter, and again at 9.50-10.15pm


22 November - Overnight low 9C, high 13C

3.45-4.45am - activity inside shelter

8.07am - left to feed; left lichen at 8.32am; back in shelter at 8.35am

11.41am - left to feed at lichen again; returned to shelter 12.11pm

3.36-3.43pm - activity outside lower end of shelter, working on silk.

4.08-4.33pm - activity inside shelter.


23 November - Overnight low 11C, high 13C

1.20am - started to become active

1.35am - moved to lower 'exit' and then remained still until

Then there was a drastic variation in rostocki's behaviour. It left the shelter at 3.17am, and disappeared from the image (the camera was covering just the area around the shelter as I had been trying to capture the process of defecation). It hadn't returned when we got up, so I went outside and panned the camera back to cover a larger area. I was relieved to spot it feeding on the 'usual' lichen at around 9.32am.

While I watched, it finished the meal a minute later and wandered off. However, instead of heading 'home' it meandered around as though lost. Eventually it found itself back at the Lichen at 9.39am. As soon as that happened, it seemed to pick up the trail back to the shelter and was back inside within a minute.

One problem with photograph (still or video) at this range is the very shallow depth of field. The lens on the cctv camera has to be focused manually so I have to guess the best position when I try to capture events like the barkfly defecating.


In this case everything seemed to be right until she lifted her rear end higher than I had anticipated, and I had to dash outside to adjust the lens by a small fraction of a millimetre. I made it just in time as she projected the pellet out of frame!

The lower images show consecutive frames in the sequence.

 At the right of the three pictures you can see a similar, spherical pellet that was projected by her two days ago, but which was 'captured' by a strand of silk. That is the only pellet produced by her that I can see in the area around the shelter.

10.04am - left the shelter to defecate

10.35am-2.15pm - periods of activity inside the shelter

2.16pm - stopped with rear of abdomen sticking out of lower exit of shelter

4.37pm - reversed out and defecated; returned inside shelter immediately afterwards.


24 November - Overnight low 9C, high 14C

7.15am - left shelter to defecate

7.47am - left shelter and headed up, disappearing out of sight.

8.20am - it reappeared and spent time grazing on algae near the top-right of the image (above the lichen)

8.32am - returned to shelter

3.39pm - left shelter and headed down-left out of view; returned to shelter at 3.49pm

The change in rostocki's behaviour continued today, with it staying away from the shelter for a much longer period than at any time since the beginning of October. It seems that it has lost interest in the lichen which has sustained it since the beginning of October.

At around 10pm barkfly nymphs started grazing in the area below the shelter. This activity continued all through the night, with at least eight nymphs in the group, and occasionally one would approach within millimetres of the shelter.


25 November - temperatures not recorded, but similar to yesterday

At 7.29am rostocki suddenly left the shelter and headed up out of the image frame. When I first checked the image at 9am she had still not returned. Five minutes later I spotted it grazing on algae some way to the right of the shelter. Soon afterwards she headed down, passing to the right of the lichen. The camera recorded her briefly just one more time as she headed back up and off further to the right. This time she went towards an area of the log which is covered with lichen similar in type to the one she has fed on since I started watching her.

She had not returned to the shelter by this afternoon and I have spent a couple of hours searching for her in vain. While its disappearance is a bit disappointing, I'm not really surprised. The solitary lichen is looking rather worst for wear, and I had wondered how long it would be before she needed to find a 'fresh one'. I will be checking the log again over the days to come, but with so many hiding places available, coupled with her tendency not to wander far, It's going to be a real game of hide and seek!

I spent a short time examining the shelter in the hope of confirming the presence of an egg (see notes for 16 October). However, that inspection didn't reveal any sign of one. at some point during the winter I need to look again with better lighting and a more powerful magnifier.

There were no further sightings of rostocki over the next twenty four hours, and despite several searches of the log I have failed to find it. The back of the log  has a thick covering of lichens, as well as mosses which are growing along the cracks in the bark, so it is very possible that rostocki has found better grazing. I will continue to check on the log during the rest of the winter, and spray it with rain water regularly when there is no danger of frosts.

Click on images to see larger version

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