pine processionary caterpillars

[Digger Dave]

Hola,

Just come across this site researching the effects of the ppc.

Many thanks for all the info.  BUT no-one seems to have addressed the problem of what to do once you've been affected.

We've been living on Cost de la Luz 6 yrs working as gardeners and we have 25 pinus pinea in our own garden so have seen loads of them.
I thought we might build up resistance to the effects but we are advised the opposite is the case. Every year the effects get worse. I've consulted the doc. but he has not been able to offer a solution.  (Typical local response of shrug of the shoulders)  & I've asked our neighbours - same response!
We use Fenistil cream to reduce the itching, but serious exposure usually means a warm shower & a couple of hours in bed to get over the 'flu - like symptoms.
Surely there must be a recognised medical treatment - course of injections perhaps.

We deal with our own by:-  Cutting down the reachable nests & burning.  Attacking the lines with a  gas flame - thrower.  Digging up the buried pupae - if you can find them! But it's all pretty grim and we encounter them all over as we work.  The fibres remain in the grass right through summer, so I always water before mowing.

I'm told that the Hoopoe does in fact eat them but I've no evidence

Seriously, I'm desperate for some qualified advice - or we may have to move to Iceland - Alaska - anywhere

[Phil James]

Hi,

Since reading about these caterpillars on the forum I've been keeping a good look out for them in the Pyrenees this year. In particular looking for nests in trees other than pines as I'm sure I remember seeing some last year. Since spring I've only found two examples of nests in other trees/bushes. First was in a wild rose and although the caterpillars had stripped a lot of rose leaves over the course of about a week the nest never really got going properly and disappeared after a week or two. The other was in a wild honeysuckle, was quite large and looked quite established. There were some caterpillars on the nest and they looked like PPC's to me - do others agree? This nest was abandoned quite quickly in the summer.

I've attached a pic as I thought you might be interested to see.

One question - does anyone know if they get PPC's in the Alps? Have there been any PPC nests spotted in the UK before?

Thanks for your help,

Phil

[potes]

Hello All,

Within this topic several people have asked about whether ppc have any natural predators or other ways in which to remove them.

Yesterday I noted several Great tits moving amongst the pine trees close to my home and they appeared to have a particular interest in the ppc nests. They each separately attack different nests and spent about 10 to 15 minutes at each nest ripping at the outer covering until the inside fell out . They would then push their heads into the broken sack that was still attached to the tree and appear to feed on the contents but they didn't appear to pay any attention to the contents that fell to the floor.

I wonder if they were actually feeding on the contents inside the nest or whether other insects had been ensnared within the ppc nest casing, a bit like a spiders web?

regards

phil

[Maria]

Does anyone else have PPC on the move? Ours are out and about early this year and so many more nests. Looks like there will be a big problem this year in our area with them. Does anyone know if the Government is doing anything about them?

[Digger Dave]

Many thanks to all for the extra info.  Yes there do seem to be more about this year - might be the mild weather.  We've since been back to the local NHS Doc and he's prescribed a course of anti=histamine - which at least gives us a decent nights sleep!
Also I've written some more info in my gardening column which can be found in the E.zine connected to www.mycadiz.biz should anyone be interested.

Meanwhile, we're still itching for a definitive answer to all this should anyone be able to help.

Digger Dave.

[Maria]

Strange this year that my friend who has had problems with PPC's over the past few years actually has no nests in her tree this year

Why is this?
Surly we could not have hair sprayed and killed all the caterpillars last year so no moths could come back to lay eggs?
Has the fire ash that we have put around the base of the tree done some trick?
Is the tree dieing and they know it but we dont yet?
Has the long summer weather made them move higher up, hence sightings of lots of nests in trees where in previous years in the Sierra Nevada there has been just a few??

Does anyone have any ideas??

Maria 

[Mel]

Hello to all.

These are probably daft questions but I have been pondering them for some time and have not been able to reach a conclusion.

Why do these p.p.c. have such strong defences? Almost a case of overkill.

Reading through the posts on this site and elsewhere it appears to me that they possess the potential to kill any mammals that come into contact with them and are avoided by most birds.

Why did this ability evolve? The birds learn to avoid them – yes, I get that but what do they gain by killing mammals? The potential predator does not live to use the lessons learned and pass them on to offspring which would appear to be more beneficial to the p.p.c.s’ survival in the long run.

Could it be:-

•   The vast majority of wild mammals do live to tell the tale?

•   In developing defences against birds (which I imagine is the main potential predator group) the p.p.c. coincidentally developed this overkill effect on mammals.

•   The was a mammal, no longer with us in Iberia/Southern Europe, that had the natural ability to survive these defences and learn from them and that’s why these  defences  evolved to such an efficient level.

•   The overkill potential is merely a coincidental side-effect of some other part of the p.p.c. ecology. Perhaps a defence against parasites?

Another point that has bothered me; the p.p.c. seem to me to be a wonderful food source for birds that can cope with them – numerous, reliable, easy to locate and yet only a few bird species are known to actively predate on them. Why not more?

Thanks for reading; any facts/thoughts anyone to help set my mind at rest?

Mel

[Technopat]

Greetings All,
Just back from me hair-raising day's walk in the mountainous hilly area of Guadalajara amid the hunters and their killer dogs - will look for relevant thread to post on - and shocked to see that the few trees infested by the nests a couple of years back - see start of this thread - had turned into the vast majority of trees now. Likewise, the nests were huge - double the size, this time round, as Melisa Beveridge pointed out in her excellent report.

A hunter we came across, a local from the nearby village, told us that the authorities hadn't sprayed the area for years 'cos of the toxic effects of the chemicals on the rest of the wildlife - maybe the wild boar end up with mushy insides like the bird Clive did an autopsy on - but that something obviously had to be done.

We came across a nest - one of those "second generation" homes, not those flimsy little things the young 'uns make - that had fallen on the ground, a great opportunity to examine it up close - something I wouldn't do if it were up in a tree 'cos the toxic hairs might be blowing in the wind. With the aid of two large and pointed sticks, I tried to open it up - literally pull it apart - to see what it was made of/what was inside. It was virtually impossible to penetrate. The "walls" were at least a centimetre thick - to the eye, like compact cotton wool - and made of an incredibly resilient "silk". When I finally managed to make a tear in it, after a few minutes of hacking away at it, it was obvious that it had been abandoned ie no squishy mash o' PPCs inside, and there were only what I took to be caterpillar scat left.

Re. Clive's

Who lives in an area with loads of wild boar? Are there big colonies of processionaries in that area or has the boar eaten them whilst they are in the ground.

, the area is heavily populated by wild boar - the signs of 'em rooting around are everywhere - but such signs do seem to be at the base of uninfested trees (difficult to prove 'cos the nests can't always be seen clearly when standing next to trunk, but certainly my impression) so not too sure that there's a relationship - although the underground nests are always a couple of metres away from the infested tree. And maybe when they go underground they do so near a tree they've selected for their next meal so they don't have to travel too far after their siesta.

Two other points:
On the one hand, the greatest concentration of nests seems to be on trees nearest the road and/or at the edge of the wooded area rather than in trees deep in the woods. As I mentioned above, it's a bit tricky to tell, but that was my impression from above the treeline.

And on the other hand, just how clear is the cause and effect of the tree being killed by the PPCs? María pointed out that maybe the blighters abandon a sinking ship way before its demise is obvious to us humans. Probably. But all the trees with nests are also full of pine needles, so it's not a case of 'em being stripped bare by voracious caterpillars who then go on to the next tree.

Not a single one of the few, obviously dying trees I looked at had a nest on it. Maybe they blow away when abandoned, but the one we came across on the ground is the first one in several years of walking in the area and it was still attached to the branch that had recently snapped off the tree.

So-much-for-me-New-Year's-Resoulution-of-short-postings regs.,
Technopat

[Phil James]

Hi all,

Thought you'd like a PPC update from the Pyrenees. There are huge number of PPC nests this winter here in the Pyrenees - many more than last year. You can see iterally hundreds as you drive in the Valle de Tena or the Sierra de Guara around San Juan de la Pena and Loarre castle. I wonder if the increase is due to very cold weather May two years ago causing the moths not to hatch until last May which was much warmer.

Interesting to read the theory that wild boars affect the PPC population - there are a lot of boar in the forests with PPCs here.

I have noticed a couple of nests in non-pines - a wild rose and a honeysuckle. Neither were full blown nests and I think they were still in their nomadic stage. The nests were inhabited for a few weeks before the caterpillars moved on.

I do think PPCs can seriously weaken trees but only when there are 6 or more nests in a single tree. I've seen trees with about 8 nests in looking very bare - some branches wiuth no needles and other with just brown needles. Around San Juan there are several trees like this.

Ayuntamiento certainly does nothing about them here and people don't seem to be bothered by them. I've not come across anyone who's been affected by them or had an allegic reaction and I've seen several Spanish cutting the nests open (I've stayed clear!).

Cheers,

Phil

[Sue]

Thanks for your update Phil, we have seen trees virtually bare of needles and as you say these have a number of active nests, perhaps 8 or so.
Those caterpillar nests that you have seen on honeysuckle and rose are not Pine Processionary caterpillars, but those of other communal species.
(Possibly a species of Fritillary on the honeysuckle)
regards,
Sue

[steveT]

Phil,

I got a rash on my ankle years ago from them in the Sierra outside Madrid. It was mild ......

steveT

[lucy]

Regarding boars and PPC, Collserola - at least the parts I go to - has few nests on the whole.  The boars certainly keep the ground very ploughed up, except in the dry season.

One thing I've always wondered about is how one of the processionary caterpillars decides to strike out, inside of following the tail end of another caterpillar.  If they all just looked for an abdomen to follow, they'd be stuck in a circle for ever.

[Phil James]

Thanks Sue - not being PPCs makes sense as the nests were too early in the year - July and the caterpillars were out during the day. I've attached a pic.

Just reread my comment and realised I didn't quite mean what I wrote - when I said I hadn't met people that have been affected by them I meant the locals - particularly the hunters who are always rummaging through the forests at night - have a kind of 'no pasa nada' attitude towards their affects. Realise they're horrible little things to be avoided!

Cheers,
Phil

[Technopat]

Greetings All,
Thanks for interesting updates.

So it now looks as if these PPCs have at least 3 natural predators, to wit, wild boar, Great tits and the whatchamallem cuckoos. The benefits to our hunter friends in encouraging wild boar to an area are obvious, while the birders among us would probably be pleased if the feathered population increased.

Re. Lucy's

decides to strike out, inside of following the tail end of another caterpillar.  If they all just looked for an abdomen to follow, they'd be stuck in a circle for ever.

apart from the nice euphemism for what where I come from we call the butt, rather than it being a case of the ppc-navel gazing, I reckon it's simply the old, old story of free enterprise vs socialism. So it goes, so it goes...

Regs.,
Technopat