A good spring for Osmia cornuta

A good spring for Osmia cornuta

My bee houses have been rewarding me with lots of activity from the Osmia cornuta in the past weeks.  I’m sure they don’t need any help to find hollow nesting places but when they choose my hollow bamboo canes or drilled-out wood I have the pleasure of watching their antics.

The first I know that some bees have hatched is the frantic activity of the males.  This 17 second video gives you an idea of what it looks like.

I admire the tenacity of the males who guard the holes against all comers.  You can get the idea in this 16 second video.

The male can be easily recognised by the little tuft of white hair on his head.  They are around several weeks before the females eventually hatch and then the excitement really mounts.

The mating is not an elegant affair and this pair managed to get stuck in the tube in a sort of impasse where neither was prepared to cede defeat.

I noticed this mating pair under the box and I was surprised by the females stoic non-resistance.  That was until I saw the photograph on the computer and noticed that the male had a firm grip on her wings and back legs.

The male eventually decided to dismount and release her.

The female is a very attractive bee and is larger than the male, which is not uncommon in bees.  She lays her eggs in hollow stems or crevices and supplies the future larvae with pollen for nourishment.  She pushes the pollen firmly in place with the help of two little horns on her head.

The horns are under the antennae and as the horns are black they are difficult to see amongst the black hairs of her head.  They are best seen in a photograph.

Once the females have emerged they begin their frantic search for the perfect hole.  Despite the abundance of choice from our point of view the females have a need to explore.

Eventually one will meet her high requirements and the egg laying and pollen collection will begin.

Pollen collecting is a serious business even if putting it in place can get a bit messy.

Isn’t nature wonderful ???

Isn’t nature wonderful ???

O.cornuta emerges 19.3.15

The first male Osmia cornuta emerged on the 19 March.  Since then he has had to put up with dull, rainy days and colder than normal temperatures.  I know that the females emerge a few weeks later but he seems completely unaware of this and faithfully visits the holes where I presume he can smell the females, still comfortably tucked up in their cocoons.

IMG_8809.male O.cornuta resting (1)

The males also play out the waiting game sitting in any of the empty holes of the bee hotel, hoping for the sun to come out or better still for the females to emerge.

Anthophora aestivalis...

It’s not just the Osmia males that are in waiting but the Anthophora are waiting too.  (I think this may be an A. aestivalis because I’ve seen its legs and it is not a plumipes.)

2 male o. cornuta (1)

But with all that waiting I think some of them must get a bit confused.

2 male o. cornuta (2)

The male in the hole is desperately trying to explain he is not a female.

2 male o. cornuta (3)

Giving up in desperation he retreats.

2 male o. cornuta (4)

Then gathers his strength to be more assertive and push his way past.

O.cornuta female

Strangely, while all this, “Shuff off, I’m not a female” was going on, I noticed a black head emerging slowly from a hole not far beneath them.  It did make me wonder that if I had noticed and they had been waiting for it to happen for two weeks that they might have been a bit quicker on the uptake.

O.cornuta fem with male

Eventually, without me having to shout, “She’s behind you!”, one of them spotted her.

O.cornuta female emerges

The first Osmia cornuta female of the season emerged!

O.cornuta mating with 3

Having had two weeks to prepare for the big event, I was a bit disappointed with what followed.  I just couldn’t see this position as efficient for increasing the population of solitary bees.  They tried the threesome, never the less, until the top one gave up.

O.cornuta male waiting on side lines

The second male moved off to watch the proceedings from the side lines.

O.cornuta getting suck in the hole

I felt the female was getting pretty fed up and then she made a clever manoeuvre towards a free hole.

O.cornuta getting suck in the hole (1)

This did not deter the determined male who hung on regardless.

O.cornuta getting suck in the hole (2)

The female managed to squash both of them into a stalemate, whereupon the male gave up.

O.cornuta female shakes free

Having shaken off her admirer the female emerged onto the surface of the log to take stock of her position.

O.cornuta female warns off male

A male tried to take advantage of her but was warned off with a defensive position and mandibles wide open in warning.

O.cornuta female grooms

With a few butt wiggles and a quick groom the female took off.  She will soon enough be mated and I am sure return to start her own nests.

The males that I have seen patrolling the bee hotel with impatience will have to get their technique improved if they hope to pass their genes to the future generation.  So far I would rate them at 10/10 for winter survival, spring survival and persistence but they are going to have to do better at their next attempt at copulating.

Osmia cornuta male

Osmia cornuta male

Carder

I was happily watching the bumble bees on the winter honeysuckle when I saw a much smaller bee that was not a bumble bee.

Back

It was moving much quicker than the bumbles and much more difficult to get a picture of it.

Side eating 2

The problem is that when it sticks its head into the flower it covers up its most distinguishing feature.

Upside down Osmia

Even though he is upside down this photograph shows the white facial hairs of the Osmia cornuta male.  They are visible while he is flying but not so easy to catch for a photograph.

Osmia cornuta male

Sideways on you can see he is slimmer than the females which should be around in another few days.  The temperature has gone up to 21 degrees C in the garden today (8 March 2015) and it was the same temperature yesterday despite overnight lows approaching zero.

I’ve put my bee hotels out today and reminded my husband that he had promised to make me another one this year.

Male Andrena

Our big plum tree is just starting to flower and I saw what I think is a male Andrena on the flowers.

Mandibles

He has prominent mandibles and I wonder whether it could be an Andrena fulva male as I always see the females on my blackcurrant bushes every year.

Solitary bee season seems to have started suddenly now that the rain has stopped and the sun has reappeared.

Osmia rufa – the good, the bad and the uncertain

Osmia rufa – the good, the bad and the uncertain

Male Osmia rufa in Lilac 28.4.13

Male Osmia rufa in Lilac 28.4.13

Before I go any further I think I should call my seventh identification Osmia bicornis as that is what BWARS uses.  I was particularly happy to see it in the garden this year as I had never seen it before.  The only mason bee to have occupied my old nest box was Osmia cornuta but more about her later.

Male Osmia bicornis diving into Lilac flowers

Male Osmia bicornis diving into Lilac flowers

The above image does not serve any identification purpose but I inserted it as I think it is cute as he stretches to reach the nectar deep in the flower.  It does, however, show he is infected by mites which will probably not cause him any harm and he should have served his purpose by fertilising the females now hard at work building their nests.

Osmia bicornis female 17.4.13

Osmia bicornis female 17.4.13

The Osmia bicornis females have two prongs on their face under their antenna.  The left one can be seen in profile in the image above but the black prongs do not come out well against the black head of the bee.  These are used to tamp in the mud they use to cement up the cells containing their eggs supplied with pollen and nectar.

In due course the eggs will hatch and the larvae will consume their provisions and go on to spin a cocoon in which they will pupate.  About 14-15 weeks after the egg has been laid, the adult bee will be formed.  The bee passes the winter in the adult form to emerge in the spring.

Now comes the good part.  I can become despondent at my lack of knowledge as I trawl through the internet or painstakingly try to make sense of an identification key.  Then the other day I found some pictures I had taken in a wood three kilometres from here about two years ago.

Osmia bicornis mating in Asphodel 13.4.2011

Osmia bicornis mating in Asphodel 13.4.2011

I was delighted to capture an image of the fluffy bees and at the time I thought they were bumble bees!  I soon realised they were not bumble bees but some sort of solitary bee.  As soon as I re-opened the file the other day I recognised them as Osmia bicornis.  That cheered me up!  It is a slow process but I am improving.

You can hardly see the female from the angle I have taken the photograph although she is considerably larger than the male.

Osmia bicornis.18.4.13

Osmia bicornis female.18.4.13

A new fixed bee hotel had been placed on the garden wall and attracted many more insects than the little, old one which hangs under the Lilac tree.  So the sunnier spot was probably the reason I was able to attract the O. bicornis for the first time.  In addition, every year I add more plants to provide pollen and nectar for the bees.

However, they fly very quickly and I was not pleased with the photographs and I am uncertain as to how to improve them.  The above photograph was taken at 1/1000 s. ISO 4000 and f 6.3.

Osmia bicornis and flies.16.4.13

Osmia bicornis and flies.16.4.13

Here I had tried ISO 320 and 1/500s. but with f 3.5, the depth of field is too short.

Hemaris fuciformis 7 May 13

Hemaris fuciformis 7 May 13

Here I have just succeeded in showing the wings of the Hummingbird Hawk Moth (wing beat frequency between 25-45 beats a second) that visits the garden by using 1/1250 s. ISO 2000, f9.  There always seems to be a play-of between quality, speed and depth of focus when the light is not strong.  I think a minimum of f9 is required but there is not always enough light to reduce the aperture sufficiently.

The highest speed my camera synchronises with flash is 1/125 s. I would love to hear if anyone has any ideas on how to improve on bee shots.

The bad news is that there were quite a lot of little flies hanging around while the O. bicornis were building their nests.  They just looked like fruit flies to me but I was suspicious never the less.  I now realise that it is very likely that these flies were Cacoxenus sp. which are parasites of Osmia.  I shall have to make a pooter (aspirator) before the next mason bee season and consider renewing the bamboos annually although this will not deal with the problem of the flies.