Cacoxenus indagator flies & bee mites: the main parasites of solitary bees
On the subject of solitary bee parasites I just wanted to share some of my experience through some pictures I took; of some of the mites that I found in my paper tubes and Cacoxenus indagator a fly parasite, so you get to see what they look like up close. Writing this was inspired by seeing the videos of disinfecting solitary bee cocoons.
When I first saw evidence of mites in my plastic tube bee observation box in June 2008, I didn’t know what had happened. Successful cells normally showed the silhouettes of an oval cocoon (vaguely visible in image with labels #4 & 5), however the cell containing mites looked to me as if a developing bee inside it had sneezed (as if having a bizarre hayfever) which had spread the pollen onto the walls of the tube. Hope you can see what I mean in the first picture (labelled #3)
On peeling open my paper tubes at the end of last year I got a real close-up of them. I would need to film this with a macro-video camera, but it was kind of spooky the way something invisible was slithering/crawling in amongst the digested/sneezed pollen dust. In this second image we see this ‘dust’ very clearly (labelled A).
What you may also notice in the middle of this image are the three larvae. These are from Cacoxenus indagator fly which I saw many times at the entrances to my tubes and tunnels. They look like fruit flies, and I have to say that I wasn’t very charitable to them.
Here’s a picture of two of them that I had photographed quite unwittingly in 2007 before I really knew what they were. The red-eyed little devils were apparently conversing amongst themselves, clearly pretending they were up to nothing sinister.
I would guess that about nearly ten percent of my tunnels were infected with their larvae when I open up the tubes at the end of last year. So I cleaned them out manually to ensure a minimum amount of infection this year.
Finding their presence in such quantities underlined the fact to me that I should not leave any tunnels with them in (if I really want to maximise my population’s potential), nor should I put drilled bee blocks in place without paper inserts that I can remove at the end of the season. I have decided that any reeds and tunnels that I have bee unable to disinfect (because I was afraid of damaging the cocoons), will be placed in a different part of the garden.
Here’s a video I took last year on my YouTube channel where we actually get a brief glimpse of a pesky fly snooping around (@40 secs hovering bottom right).
…and finally an even more interesting moment, this last video where we see a solitary bee female doing some spring cleaning of a tunnel of my bee observation box. It wasn’t till afterwards that I realised that I had recorded her tugging out an old empty cocoon (@35s & 48 seconds) and returning to the same tube. Oh yes, and there’s also another pesky Cacoxenus indagator glimpsed at the bottom of the shot hovering just underneath the box @30s.
February 2nd, 2010 at 1:01 am
[...] Mason Bees and other native bees « Solitary bee expansion project – cascades Cacoxenus indagator flies & bee mites – parasites of solitary bees [...]
February 3rd, 2010 at 2:49 am
The non-condo population can bring the mites, but essentially any visitor that comes to the condo that has picked up mites (Chaetodactylus sp.) whilst visiting flowers, or during mating can introduce them to the condo. The mites consume the pollen/nectar pillow which competes with the developing larva within each cell. The trays are cleaned with a stiff brush, either wire or plastic etc. We don’t use bleach or “cook” the trays to kill the mites as this can warp the trays.
Yes, please pass on, but hopefully you’ll give us credit. That’s why we put this up on the net. We’ve had professionals over the years essentially steal our ideas/inventions and claim that it’s theirs. Not a biggy, but quite annoying on a personal level. This way, we can point to Youtube for evidence when we actually put it “out there”. We’ve been using it for years.
Our Hutchings Peek-a-Boo trays really revolutionized my research when I did counts of egg-laying efficiency over the Spring and Summer. I could document how many eggs were laid over time that way. Extracted cocoons were placed individually in test tubes in the exact position that were originally in the channel which when emerged, I could be guaranteed of a sex determination to prove scientifically. This was specifically helpful in showing the most efficient length of channel for this species of bee for female progeny that were laid down, and I could free the bees from the tubes so no mortality for science. I wrote a paper but have yet to publish it. Many years old now and wish I could get someone else to take up the thesis. If interested, I could send to you in its unfinished state complete with graphs.
Gord
February 22nd, 2010 at 10:41 pm
Hey Paul,
Just remembered about this little article I wrote for out gardening centre here in Victoria. Thought it might bee interesting for you perhaps?
Anyways, here it is at: http://www.compost.bc.ca/newsandevents/newsletters/The%20Latest%20Dirt%20Fall%202008.pdf
Cheers,
Gord
March 7th, 2010 at 4:20 am
Waiting for your next excellent post on solitary bees. Wonderful blog!
Can’t wait for my cocoons and bee tubes I ordered from a supplier to arrive in a couple of weeks.
Setting my best friend up with some too- she’s a half mile away. More bees better!
March 13th, 2010 at 6:56 pm
Thanks Gord and Omie.
Gord – that’s a very good little article you wrote there. I would be interested to hear more about why you put color dots on the surface – is that for you or the bees to keep track of the trays? Feel free to tell us if/when you start running your courses on Mason bee keeping – would be glad to help you publicise.
Omie – let us know how your bees get on… would also be glad to hear you talk about you and your friends efforts in starting up. You can even write a little piece if you want, and if you have no other place to put it online, I would be honoured if you would like to share it here. I will also be putting a Forum in place here wery soon if you want to share and pose more questions.
Cheers, Paul.
March 17th, 2010 at 2:45 pm
Hi there Paul
Just a a note to say how lovely to find a blog about solitary bees!!I am an artist and will be having a small show in London in June to promote interest in these delightful and rather neglected little bees. I am actually in the USA for a while and was initially researching USA bees for a commission and had some wonderful Osmia species sent to me by an orchard bee specialist, O cornifrons, O lignaria which they call BOB’s here and the beautiful little O aglia. I keep a blog about it all and have just added you to my Solitary Bee Links page.. I know you are in France but think all you have to say is very relevant to the UK.
I will also follow you on twitter but I am a bit new to it! I seem to be getting quite a bit of support and encouragement in trying to get solitary bees a bit better known and appreciated. I will follow your progress this year and blog about it. I have in fact just redrawn the O rufa, not on the blog yet but can send you a copy ..
March 17th, 2010 at 7:55 pm
Thanks Valerie,
It is great to hear from another fan of solitary bees – they need our help, above all in finding suitable accommodation. I will certainly take a look at your blog and at least, link back to the pages when I get another post up. Having carried out a brief scan of it (am at day job), I am very very impressed. I look forward to looking at your work in detail.
If you are also a facebooker and fancy join the “Campaign for solitary bees” or tell your friends about it, we are launching our manifesto very soon.
Cheers, Paul.
March 22nd, 2010 at 12:54 am
Hi Paul,
You asked about colours on the outside of the trays – it serves two purposes, although mostly for the dumb humans that watch the bees. Yes, it is a stair-falling-down system as well as a minor bee orientation ploy, but mostly the former for us to make sure we put back in the same order. Imagine if you showed up at your flat and someone had shifted the floors all around? Bees kinda’ like to know exactly where they left off instead of depending on their own scent.
It’s kinda’ far away from me where you are but my next class is March 27 at the Victoria Compost Centre. My Fall cleaning classes aren’t until November 20 (http://www.compost.bc.ca/learn/communityeducation.htm).
Thought you might like to see some of the bee discussions that go on around Vancouver/Seattle/Victoria on GardenWeb (http://www.gardenweb.com/). I’ve been contributing wherever I can. Some “experts” like to spar about what they think they know without doing much in the way of scientific methodology.
Thanks for the inspiration.
Cheers, Gord
May 9th, 2010 at 10:37 pm
Thanks for that info Gord
Judging by my bee behaviour when they come back to the tunnels, on further reflection I think any markers that help them identify the tunnel or section they are working on is actually useful.
I hope your classes are well attended – happy to have your link to them on here – would love to see how they go if you make another video or two.
Sorry I was very slow in coming back to you on your blog – I was changing jobs right in the middle of the bee season – and I note you have decided to pull it off-line. I would be happy to give you what help I can now I have more time on my hands when you set up another one.
May 15th, 2010 at 2:20 pm
I’ve been squishing those cacoxenus indagator flies when I get a chance. They are pretty lazy and easy to splat. Next year I will create a hatchery for the coccoons which I will clean with sand to get rid of the mites.
May 16th, 2010 at 9:51 pm
Haha – yes, they are pretty lazy and easy to squish jo0ls!
I have the impression that out of earshot of humans they are very polite – saying “good morning – lovely sunny day for a flight” as the mason bee emerges.
Sometimes I think I can also hear a barely audible whistling as they pretend to be looking at something else when the mason bee female returns.
However we know what they’re up to.
This morning (16th May) I had a weird experience in respect of this. Whilst watching my bees on the ladder one of the last remaining Osmia cornuta females emerged from a paper tube with something attached to her back leg. She then flew directly sideways towards me and hovered by my left ear. The ‘thing’ dropped from her leg and landed on my shoulder. It was the body of a dead parasitic fly. An entirely micro-weird moment.
I will be cleaning the cocoons in the late autumn before they become young adults and with the reflex to become stressed. Good luck with the rest of your population this year. Do come back and tell us more about them.
Regards, Paul.
May 19th, 2010 at 11:42 pm
Well, here’s a video showing my boxes, and the local birds…
http://www.youtube.com/user/jo0ls#p/u/6/yLvIfY-BSws
May 22nd, 2010 at 3:15 pm
Thanks for sharing jo0ls… it’s interesting those birds are really taking advantage of the solitary bees – but it’ll all naturally rebalance out in the end; it’s what ecosystems and food chains are all about.
December 5th, 2010 at 6:51 am
Hey Paul,
It’s cocoon extraction and condo cleaning season here and I’ve just finished my last class. However, I wanted to show you the sand cleaning method, but using a tube instead of a jar. So, I put up some photos from the last class, plus a demo of a clear tube I made so folks can see what goes on inside the tube. I don’t have it on Youtube but it’s on my website. It can be seen at http://sites.google.com/site/hutchingsbeeservice/how-to-clean-bees
I have a very busy Spring coming up with lots of public presentations and classes, plus I’m now able to show off my entomological talents (instead of mason bee hobby), by bringing into it, my knowledge on our native bee species and their life-cycle and biology. Just thought I’d pass things along to you from here in Canada.
Cheers,
Gord
February 24th, 2011 at 4:22 pm
Gordon – Thank You SO Much for all the great info on OMB’s! Do you use 1 x 8 x 12 pine boards for you peek-a-boo trays? Are the groves 7mm wide and 7mm deep? Does it matter what type of clear plastic you use on top? Again Thank You!!
March 17th, 2011 at 1:19 am
I was hoping to get some advice. I have a bee hive in my back yard. It has been very successful for the past 4 years. Before this, each hive would start acting strangly and soon die. Today I saved a few bees from my swimming pool and I thought they were showing weird behavior. I looked closer and saw tiny yellow-oarnge short worm shaped things on the bees backs. Is this something I can help to protect the hive?
Respectfully,
Nicole
May 16th, 2011 at 1:12 pm
Thanks sooooooo much for this great site and all the good information about solitary bees. I set out two bundles of cut bamboo sections in my yard in New York City. I managed to insert rolled paper tubes into the bamboo, but it’s not really easily removed. I figure I’ll just use these for this year and set up a better system next year, so I can inspect and clean the bee cocoons in the future.
To my delight, I already have four of the bamboo tubes capped with mud by Osmia cornifrons. Two bees are busily working on two other tubes. This was all a treat, until today. When I was trying to get a few photos of the bees coming and gong about their work, I notices a little fly hovering around. I got a good shot of it when it landed on the front of the condo. After googling around, I found photos of it….the dreaded Cacoxenus indigator. Grrrrrrrrrrrrrrrrr!!!!! I’m really bummed out that they found this little, new condo so quickly.
Is there any way to discourage these little @@ #$%#$%&s?
I was planning on leaving the condos out through mid summer, expecting that I might get some leaf-cutter bees move in to some of the empty bamboo tubes.
I’m feeling guilty that I’m dooming my bee babies to the flies.
Disheartened in Brooklyn,
Jess
March 23rd, 2012 at 5:17 pm
[...] Mason Bee – how many is too many ? Think this is likely to be Cacoxenus indagator Cacoxenus indagator flies & bee mites: the main parasites of solitary bees | Solitary Bees these are the smallish black flies in the 4th picture down, saw quite a few of those last year [...]
April 6th, 2012 at 12:51 am
i hate those darned little flies. they are the only bugs i squish. is there no way to repel them?
April 7th, 2012 at 3:47 pm
Paul, I have been viewing your excellent site for a while now. Mason bees have been part of my family life for quite some years now and its great to see other people keen to tell others about them. the internet is really useful for this. It was n’t available when I started!
Beside my new bumblebee nest box found on above site, I will have news that I know will interest you very soon!
Cheers! Great site! George Pilkington whose mason bees are still asleep, thankfully!
April 8th, 2012 at 11:40 am
I haven’t found a way to repel them Angela. I did wondered this winter whether I would try and test out something like a vinegar trap (seeing as they look like cousins of Drosophila fruit flies), however it has turned out that my longer term management of the tunnels post-nesting has been more effective. So far after 20 days of activity I have only seen 3 flies and the first lone fly appeared last week. Usually I would be regularly up and down the ladder trying to squish the new ones everyday, but my only solution has been persistence and evidently it has paid off. I access the reed or paper tunnels, removing the fly larvae from the cell chambers by hand and I am thorough about it. If I have doubts about whthere there are fles tucked away in a cell corner, I remove the bee cocoons and clean them rather than leaving them in the half open reeds.
What sort of tunnels are you putting out Angela?
Paul
April 10th, 2012 at 12:43 am
i have bee condos with paper inserts which i hope to remove and inspect in the fall. i will then store the cocoons on a closed corrugated tray until next march. i think i might attempt the sand bath, also.
do you actually look for fly larvae in the tubes while the bees are still active? i know how jess in brooklyn feels. when i see those darned flies i feel that my bees are working for nothing. i squish every fly that i see.
~angela
April 28th, 2012 at 8:38 pm
When I removed the bee cocoons from last year’s bamboo tubes, I only found two or three cells with fly larvae in them. Thank goodness…not too bad. That was my first year. It’ll be interesting to see how things go this year, now that I’m more vigilant. If I see those !!@@## critters, I’ll have no hesitation giving them the squoosh. Leave my bees alone! Dang it. LOL
Three of this year’s bamboo canes are capped already. The kids are busy. We had a very warm winter and early spring, here, in New York City. The past week or so, the weather has dipped back to chilly temps…upper 30′s/low 40′sF. Many complaints upstate from fruit orchards about damage to orchard flowers. I hope the bees and other pollinators are OK with the low temperatures. We’ve had an extremely crazy winter and spring.
Good luck to all. Have a wonderful season! Looking forward to staying in touch. I love this group!
Jess
April 28th, 2012 at 9:21 pm
Hello George,
Sorry for my slow reply. I look forward to hearing your news, especially as it sounds like you have some experience that I could learn from. Would be nice to hear about some of that.
You are very generous about my project – that’s a great compliment coming from someone who has a great site and makes a solid contribution to the environment; unfortunately though, my day job has nothing to do with bees or nature, and I have been distracted for the last couple of years. My blogging has been slowing down. However, on the upside the Facebook fan page (about to hit 800 fans by end of June 2012) and the micro-blogging on Twitter as well as my videos have kept me getting the message out.
I hope when you have the news you will find a way of sharing it with us.
April 28th, 2012 at 9:43 pm
Hi Jess.
If your bees were nesting wild nearby before you offered tunnels, then this ecology (the parasites and predators) will continue to find your tunnels. However perhaps there is a hidden positive side to this. As the flies are attracted to crowds or bee aggregations (as the entomologists call them), the wild flies may eventually only focus on your tunnels where the bees are happy and where most of the nesting action is – these one road towns where you’re the sheriff very able to hunt the mangy scoundrels down.
Thus you’ll get the upper-hand when you subsequently disinfect the tunnels in the fall. Within a couple of years, like me, you could get to the point where you rarely see the flies. I have only seen four flies this year in 6 weeks. This suggests that the flies are getting sucked in by all the activity and the disinfection process is working; two years ago I was squishing more than four a day.
I concur with your view of the weather – we have had a crazy winter and spring. It seems that the UK weather (and 36 hours later France), often seem to be ripples of what you’ve had on the U.S. East coast. Anyway I hope your season picks up. If the bees have been around 200 million years I think they’ll survive a few chilly days staring out at the grey skies.
April 28th, 2012 at 11:40 pm
Hi Angela,
If you look at the second picture above and the second bee chamber marked ‘B’, you will see the swirls of the Cacoxenus indagator fly larva’s poop. It can be quite distinctive, with a seemingly brighter yellow or orange colour as opposed to a chamber infested with mites which can be quite dull. Here’s another picture that I took last year showing an elongated trail of their stuff.
I use a watercolour size paintbrush to sweep them out of the chambers without damaging the cocoons. However the trick in catching all the larvae is realising two things:
This means that there’s always a risk that one C. indagator fly larvae may get tucked out of sight when there’s a curved cell partition wall, or if walls break or crack when you open and inspect the tunnel. So I make a point of deliberately taking the cocoon out of an infested chamber and cleaning away the whole chamber (including adjoining walls) rather than assuming I have got all of them. As these fly larvae are numerous and eat quicker than the bee larvae, these infested chambers also result in smaller cocoons.
When I find an infested mite chamber, I do the opposite. I get all the other cocoons out before I dispose of the infected tunnel, as mites at this stage are too small and translucent to be fully identified and accounted for.
Hope that helps.