Sunday, 12 April 2015

The Birds & The Bees

At this time of year especially, you'd be forgiven for wondering what a title like that might allude to! Nothing explicit here, I promise, just a brief mention of a few pretty birds around Tring reservoirs last week, and then a switch to the dark and divisive world of mining bees. These tough little loners aren’t afraid to dive into combat, writhing around in the dirt, bodies discarded left, right and centre. It’s worse than a "Die Hard" feature! But, more on that to come...

First up, a pair of Mandarins on Wilstone reservoir on Friday, on choppy waters.



A pair of Garganey were also around and I spotted my first Common Tern & first House Martin of the year - a single bird of each flying amongst the Black-headed Gulls over the barley bales.

But, it was earlier in the week, along the footpath of the NW shoreline of Tringford reservoir, that there had been this mass emergence and frantic, aggressive mating event of mining bees, worthy of an 18 Certificate. I’ve not been able to narrow down the ID from the broad classification of an Andrena species. With at least 60 to choose from in the UK, it's not straightforward, although there are a handful of likely candidates. (Note: see update at end of post, on 13/4/2015 - species very probably Yellow-legged Mining Bee (Andrena flavipes)).

In spite of coming across a good 200+ busy bees all zooming about the sandy pathway together, these guys live solitary lives. Females can and will share entrance holes to nest burrows but that's as sociable as they get. The female digs her own chamber underground and, after mating (if she survives!), she’ll deposit each egg in a sealed cell with pollen and nectar.

Entrance hole (approx 7mm diameter) and a bee using an alternative route!

The bees were approx 12mm long. There were subtle but distinct differences between the sexes. The males (I presume) were a little more slender and lacked the dense, rich orange scopal hairs on the hind legs.

Male on top of female
Female (left) & Male (right): note the female's rich, darker orange scopal hairs on hind legs

I took some video footage with my macro lens (my first attempt - bigger depth of field needed next time). The opening scene appears fairly innocuous: bees buzzing around the path where there were 100s of tiny entrance holes to chambers underground, often just 5cm apart. Getting a little closer to the action, I filmed one hole and it revealed a number of males going in and then backing out, presumably looking for a female. However, getting intimate, the behaviour I most wanted to capture was the aggressive, mass mating attempts (I assume, although, the violence and mortality rate looked decidedly counterproductive!). Females were mobbed by numerous males, all seemingly trying to mate with her. Bee bodies were strewn along the path, listless or lifeless, both male and female causalities. In fact, I managed to photograph a male apparently feeding on or killing another bee with his tongue (see, I told you it was worse than "Die Hard"!). I can't quite discern whether it's another male or the female he is attacking (there are 3 bees involved)?! Either way, the female ended up dead/dying.

A male with his proboscis (tongue) in another bee's thorax!
Dead/dying female

Back to the video footage. As you watch the ball of bees rolling around on the ground, picking up dirt and horse hairs, it’s possible to spot the single female in amongst them. She has the rich, darker orange scopal hairs on the hind legs. I slowed down a sequence of footage which shows her seemingly trying to escape the clutches of the males, only to be pulled back into the ball (I removed the audio as it was mostly road noise).


I would love to know what species of mining bee this is and to get a better idea of what on earth was going on in this gladiatorial mating frenzy. Comments/mails welcome.

A little shy - A preening Greylag Goose by Marsworth reservoir last week

Update 13/4/2015: I've been following a mining bee sighting on ISPOT which looked identical to the bees at Tringford. The identification given there is for a Yellow-legged Mining Bee (Andrena flavipes). After doing a little research, I'm satisfied this is probably the correct ID for these bees. There's a nice fact sheet on them HERE. "The males look different to the females. They are slimmer, covered in sparser hair and lack the dense brush of orange-yellow hairs on the hind leg" & their length ranges from 10-13cm. Both these facts, as well as appearance, fit exactly with my observations. They are common in southern England, will collect pollen from a wide range of plants and flowers, flying from March to May and again from June to early August.

4 comments:

  1. What beautiful ducks and frisky fuzzy bees. Beautifully captured and an interesting write up. Nicely done! from ARF

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  2. A great series of shots Lucy and love the video, always nice to see some action.

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    1. Thank you Marc. I don't know about you but I find macro work a lot more difficult to get right than long lens photography, especially when my subject is moving faster than I can follow with my eyes! Achieving the correct point of focus and adequate depth of field is extremely difficult when these tiny critters don't sit still ;o). Give me a torpid Toad any day of the week, lol.

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