Andrena male big head huge jaws!

[JRsbugs]

Hello!

I know Andrena bucephala has a big head and jaws, this looks to have red tarsi too.

Only the two shots, taken on 27th July on Ragwort in my garden. Hopefully this is enough to say what it is, being so distinctive!

Janet

[JRsbugs]

I had several more photos of the same bee taken a few minutes before the two shots I posted! I hadn't looked at them properly but they are the same bee, it is after all a while since I took them!

[Dillybythesea]

Massive head! Will be fascinating to find out what it is!

[JRsbugs]

The other one with a big head is Andrena ferox, it has a limited dustribution but as I recently had Ferdinandea ruficornis with a very limited distribution I guess it's also a candidate. I can only find a photo of a female A. ferox.

http://hymettus.org.uk/downloads/A%2...eport%2008.pdf

I had a couple of unidentified females in spring, one I posted on bwars yahoo which looked similar to A. bucephala but nobody said boo. I'm sure I posted it here too, if I could find the photos. I think I thought it looked like Andrena humilis until I saw someone post bucephala on bwars group. I know it was on 1st April, and I could load the photos but this male shouldn't cause too much of a problem?

[JRsbugs]

I found the female bee which I posted before, I still don't know what it is but it looks similar to the photo of A. ferox on hymettus.. along with a few others!

Andrena humilis?

[eucera]

A. denticulata perhaps? A. ferox is an Oak forager with a very short flight period in early May

[JRsbugs]

That does look good for the male Stuart. I noticed the small tooth last night. There's not a lot of photos on the internet, found one of Tristan's on flickr which is a male. It does look to have a square head at the back, but does it have such a big head?

Andrena denticulata | Flickr - Photo Sharing!

I see A. denticulata specialies on Asteraceae, and the flight time is correct so that's two points in favour as well as the tooth making three!

wild bee

[JRsbugs]

I've been trying to make head and tails of Saunders key descriptions.

A. denticulata:

A. denticulata, Kirhy[Listerdla, Kirb.).—Black, head
and thorax clothed with very pale brownish hairs, intermixed
with black on the vertex of the male and on the centre
of the mesonotum in both sexes; vertex shining, quadrately
produced behind the eyes in the male, it's posterior
margin deeply emarginate, in the female dull and of normal
form, mandibles in the male long and falcate, labrum with a
quadrate, deeply sulcato tubercle; mesonotum somewhat
dull, finely punctured except the scutellum, which is shining
and remotely punctured, propodeum finely rugose, densely
fringed laterally with pale hairs, it's basal area more or less
shining at the sides; abdomen subelliptic in both sexes,
shining in the male, nearly dull in the female, basal segment
thinly clothed with pale hairs, second and following segments
with short erect black hairs in the male , subdecumbent
in the female, the apices of the segments with a band of pale
hairs, narrow in the male, broad in the female, that of the second
segment interrupted in the former sex, apical fringe brown-black,
segments beneath fringed with long pale hairs, male
with the apical valve rounded at the apex; legs piceous,
clothed with pale hairs in the male, with pitchy-black in
the female, the tarsi piceous, hairs of the femora pale, of the
tibiae and tarsi reddish-brown, those of the tarsi brightest.

I had to make some corrections as symbols don't copy!

That takes some understanding, but I went through it step by step and most seemed to fit except there's no mention of the tooth on the ventral base of the mandibles. The bit which says "labrum with a quadrate, deeply sulcato tubercle" can't be seen and I doubt relates to the tooth.

The final "the tarsi piceous" certainly doesn't seem to fit either, it seems to refer to both sexes as the mention of the female prior to that refers to the hairs on the legs and the description following that "hairs of the femora pale, of the tibiae and tarsi reddish-brown, those of the tarsi brightest" appears to refer to the hairs and not the tarsi colour.

A. bucephala male should have reddish tarsi, but also the very base of the tibia but whether this is variable I don't know as Saunders states:

legs black, clothed with pale hairs, the extreme apices of the
tibiae and all the tarsi pale in the male

The very base of the tibiae of my male are not pale, and on the SLovenian site the flying period is given as April and May for A. bucephala which is a little early even with an extended season.

wild bee

Andrena ferox in Saunders:

A. ferox, Smith.—Black, head and thorax dull, finely and
irregularly punctured, clothed with brownish hairs, which
are paler in the male, in which sex the head is very large, sometimes
exceedingly so, and the mandibles angulated, and
sometimes spinose at the base outwardly, the antennae long,
with the third joint slightly shorter than the fourth, in the female about equal to the fourth and fifth together ; mandibles
in the female widely membranous beneath ; wings subhyaline,
nervures very pale, propodeum with the basal area
somewhat shining, its sides rugulose ; abdomen sparingly
clothed with pale hairs, shining in the male, very remotely punctured,
with the apex of the first and second, and sometimes the
base of the second and third segments widely testaceous,
dull in the female, with the apical margins only of the segments,
paler, fringed with pale hairs at the sides, apical fringe brown,
segments beneath fringed with pale hairs, base of the abdomen
testaceous in the male, legs piceous, clothed with pale
hairs, the apices of the anterior and intermediate tibiae, the
posterior tibiae, and all the tarsi in the male, the posterior tibiae
and tarsi only in the female clear testaceous, scopae golden.

Several points to pick out here which match my bee:

"base of the abdomen testaceous in the male"

The word testaceous having two meanings, one of them being of any of the several light colors of bricks

Testaceous - Definition and More from the Free Merriam-Webster Dictionary

My bee does have this colouring at the base of the abdomen, visible in the side views.

This also fits:

"male, in which sex the head is very large, sometimes
exceedingly so, and the mandibles angulated, and
sometimes spinose at the base outwardly"

This doesn't quite fit though, I wouldn't say the apices of all tibiae are "clear testaceous":

"legs piceous, clothed with pale
hairs, the apices of the anterior and intermediate tibiae, the
posterior tibiae, and all the tarsi in the male, the posterior tibiae
and tarsi only in the female clear testaceous"

The Slovenian site states A. ferox as flying from April to June, which is getting closer.

wild bee

To summarise, we have description of A. denticulata which doesn't mention the tooth at the base of the mandibles, and A. ferox which can sometimes have a tooth at the base of the mandibles.

So why is A. denticulata given that name, suggesting it has a tooth? It would appear to be because of the "labrum with a quadrate, deeply sulcato tubercle"

Given the evidence, this looks to me to be pointing towards A. ferox more than any other unless I have misunderstood what I have read, or Saunder's keys are not correct.

The flight period does fit Andrena denticulata, but as we know bees don't read which seasons they should stick to and there is the matter of denticulata having black tarsi, according to Saunders and if I have understood that correctly.

wild bee

[Matt Smith]

Saunders descriptions wil be correct - he may not mention the tooth a the base of the mandible (which A.denticulata does have) as he may not have considered it a good character, or perhaps he had written his keys (which I have not used for a while) so that there were several species with genal teeth that were being separated - if they all have a tooth the presence of it is irelevent.

Sulcate means "grooved" - the tubercle has a groove running through it and can sometimes appear to be 2 separate "bumps"

A.ferox is a rare as hens teeth in the UK, so its not going to be that.

Flight times in Slovenia will be very different from ours for many species - Slovenia has a continental climate - we dont.

[JRsbugs]

Originally Posted by Matt Smith

Flight times in Slovenia will be very different from ours for many species - Slovenia has a continental climate - we dont.

A.ferox is a rare as hens teeth in the UK, so its not going to be that.

I realise Andrena ferox is rare Matt, but that is not a sound basis to discount it.

How rare is Ferdinandea ruficornis? 20 (+1) known post 1960 sites unless that figure is outdated. I had it this year, confirmed by Martin Speight.

Hoverfly Recording Scheme - View topic - Ferdinandea ruficornis

Diptera.info - Photo Albums: Ferdinandea ruficornis (female) (3)

Diptera.info - Photo Albums: Ferdinandea ruficornis (female) (4)

Also a probable Cheilosia uviformis which as yet is not recorded in the UK but there has been some finds...

Diptera.info - Discussion Forum: Cheilosia latifrons? > probable uviformis male

Hoverfly Recording Scheme - View topic - Cheilosia uviformis

I have had several other rarities too.

Yes I realise what sulcate means Matt, it was the 'denticulata' which infers "teeth" or bumps. It does seem strange all the same that Saunders didn't mention the tooth, other features are described in detail.

This year has been an unusual one, I had other species such as Bombus rupestris much earlier than usual, and you know B. lapidarius males appeared much earlier, so why not later?

Do you have an idea as to which it is Matt? Experience is useful, something I don't have as much of as yourself or Stuart. What do you make of the tarsi colour for A. denticulata? Do you also think it's likely to be denticulata?