Megachile (7)

Megachile
Megachile are commonly known as Leafcutter Bees. Seven species are found in
Norfolk. Their mandibles work like scissors to
cut pieces out of leaves or petals to form their
nests. Several species make their nests in
crevices or holes in timber whereas others use
holes in sandy ground. Those requiring timber
tend to be absent from the coastal strip,
whereas those which nest in the ground often
have a coastal bias in their distribution. All
have two submarginal cells on the forewing
and the tongue is quite long. Their name
comes from the long tarsal claws which lack
an ariolum between. Their characteristic
posture, with tail in the air on alighting, makes
these bees easy to spot.
It is often possible to identify Leaf-cutter Bees
from good photographs. The scopa hairs
beneath the abdomen differ in colour
between species, but the scopa needs to be
seen without pollen.
Males can be
distinguished from females by the male’s lack
of a scopa and their longer antennae. They
emerge about a week earlier than females
and for the first few days, before it fades,
their hair is bright ginger-brown. The males of
three species have distinctive white swellings
on the front tarsi and the male of another
species has very green eyes. Bees in the genus
Coelioxys are brood parasites of Megachile.
Megachile centuncularis female.
Megachile ligniseca female cutting a leaf.
Thriplow Cambridgeshire 13th August 2014
Megachile centuncularis
Females have pale hair on the clypeus and
thorax, but there are some dark hairs on top
of the head. The abdomen has pale marginal
bands at the edges of tergites 1-5, with hair
length decreasing from T1-T5. There are
bands of sparser, longer hairs on T1 and T2.
The scopa is entirely orange and the hairs
protrude outwards making them visible from
above. Males have pale hair on the clypeus, a
mixture of dark and pale hairs on the top of
the head and thorax. The abdomen bears
similar marginal bands to those in females.
‘bee hotels’. Rose leaves or petals are often
used in gardens.
Parasites Coelioxys inermis.
Flight times June-August
Distribution One of the commonest Leafcutters in the county, but there are few
records from the west. Scarce on the coast,
though reported from Scolt Head.
Megachile centuncularis female taking nectar
from a garden Coneflower. Weybourne 2nd
August 2015
Megachile centuncularis
4
3
2
1
0
9
8
2000 – 2014
1980 – 1999
Pre 1980
5
6
7
8
9
0
1
2
3
4
5
Habitat Heathland, commons, gardens,
waysides, Breckland rides.
Flowers visited Garden Agyranthemum
(Asteraceae), Alkanet, Bramble, Crown Daisy,
Fleabane, Green Coneflower, Hemp agrimony,
Lamb’s-ear, Lesser Knapweed, Meadow
Cranesbill, Meadow Vetchling, Purple
Loosestrife, Ragwort,
Nesting Nests are made in a variety of cavities
in wood, buildings or hollow stems, including
Megachile centuncularis male on garden
Marigold. Weybourne 3rd July 2013
Megachile cirumcincta
Females have long body hair which is black on
the head and also on tergites 4-6. The scopa is
brown at the base and black at the tip. Males
have white clypeal hairs and an expanded
white area of cuticle on the front tarsi.
Flight times May-August
Distribution This is the rarest Leaf-cutter in
the county, but there are recent records from
dunes at Caister and at Great Yarmouth (TS
2007 & 2015). There are also records from
Horsey Dunes 1958, Scolt Head 1975 and from
the Brecks 1998.
Megachile circumcincta
4
3
2
1
0
9
8
2000 – 2014
1980 – 1999
Pre 1980
5
6
7
8
9
0
1
2
3
4
5
Habitat Coastal dunes
Flowers visited Bird’s-foot Trefoil.
Nesting Nests in sandy ground. Not observed
in Norfolk.
Parasites Coelioxys spp.
Megachile leachella
Females have pale body hairs with a tint of
brown on the head and top of the thorax.
There are complete white marginal bands on
all tergites and a characteristic pair of white
hair patches on the last tergite. The small size
of this species is also a clue to identification.
Distribution This is largely a coastal species,
but there is a record from Roydon Common
1996 and one from Santon Warren 1986.
Megachile leachella
4
3
2
1
0
9
8
2000 – 2014
1980 – 1999
Pre 1980
5
Megachile leachella female on Wild
Mignonette. Weybourne Camp 12th August
2015
Males have white hair on the clypeus and
orange-brown hair on the top of the head,
thorax and abdomen. There are complete
marginal white bands on the tergites. T6 has a
covering of pale hairs and bears short
terminal spines. The eyes are a vivid pale
green. They are often observed basking on
sandy ground close to nest sites.
6
7
8
9
0
1
2
3
4
5
Habitat Sites with loose sand or sand dunes
where small sandy cliffs are present for
nesting. The north-east cliff faces are not used
but places with loose sand at the cliff-top can
be, for example West Runton beach car park.
Flowers visited Greater Bird’s-foot Trefoil,
Bramble, Catsear, Charlock, Crucifer sp.,
Fleabane, Haresfoot Clover, Hawkweed,
Heather (Ling), Oxford Ragwort, Ragwort,
Restharrow, Sheepsbit, Wild Mignonette.
Nesting Nests are made individually on
sloping or level sandy surfaces.
Parasites A small form of Coelioxys
mandibularis attacks this species in large dune
systems on the coasts of Kent, Sussex, South
Wales and Lancashire but it has not been
recorded in Norfolk.
Megachile leachella males showing green
eyes; Holkham 8th Jule 2009.
Flight times June-September
Megachile ligniseca
Females are large with pale brown hair on the
clypeus and thorax and black hair on the top
of the head. There are long pale hairs on T1
and T2 and pale marginal bands. The scopa is
white anteriorly, grading to pale orange at the
back. The dark hairs on the surface of the last
tergite are flattened against the body and the
tip of the abdomen has a small indent. Males
have pale hairs on the clypeus, pale brown
hairs on the top of the head and thorax and
pale marginal bands on the abdomen
consisting of moderately long hairs. The
abdomen is almost parallel sided and has a
notch at the tip.
Megachile ligniseca male (faded) at nest hole
in bee hotel. Thriplow Cambridgeshire 19th
July 2015
Flight times June-September
Distribution Moderately common in the east
and in the Brecks. No records from the northwest or the Fens.
Megachile ligniseca
4
3
2
1
0
9
8
2000 – 2014
1980 – 1999
Pre 1980
5
6
7
8
9
0
1
2
3
4
5
Habitat Commons, heathland, river valleys,
mature dunes, gardens, open Breckland and
brownfield sites.
Flowers visited Garden
Burdock, Creeping Thistle
Scabious, Fleabane, Bell
Knapweed,
Melancholy
Loosestrife, Spear Thistle.
Megachile ligniseca female. Thriplow
Cambridgeshire 11th August 2014
Aster, Bramble,
, Dandelion,Field
Heather, Lesser
Thistle, Purple
Nesting Nests in hollows in wood or stems.
Parasites Coelioxys elongata observed at a
garden nest site in Cambridgeshire.
Megachile maritima
Females are large and broad with brownish
hairs on the clypeus and thorax and varying
amounts of black hair on the head, thorax and
abdomen. The scopa has whitish hairs. Males
are large and broad with ginger-brown hair
when fresh. The fore tarsi are expanded with
a white cuticle fringed by white hairs. The
hind tibia and tarsi are swollen. Males move
rapidly from flower to flower and sometimes
defend territories.
which he often clung to as the pair fell to the
ground.
Flight times June-August
Distribution A coastal species also occurring
at sandy inland sites near Norwich and in the
Brecks.
Megachile maritima
4
3
2
1
0
9
8
2000 – 2014
1980 – 1999
Pre 1980
5
6
7
8
9
0
1
2
3
4
5
Habitat Coastal dunes and inland sites with
bare sand.
Megachile maritima male on Bramble.
Weybourne Camp 9th July 2015
Nesting Nests in sandy ground, sometimes in
aggregations (SF)
Flowers visited Bramble, Haresfoot Clover,
Sheepsbit, Restharrow, Ragwort, Vipers
Bugloss, Greater Knapweed.
Parasites Coelioxys conoidea (qv).
Megachile maritima male (faded), grooming
antenna. Winterton Dunes 17th August 2015.
This bee repeatedly returned to the stem
from which he launched attacks on other bees
when they alighted on nearby Bramble
flowers. His target included bumblebees
Megachile versicolor
Females are similar in size and appearance to
M.centuncularis. The scopa is orange but with
dark hairs on sternites 5 and 6. The marginal
bands on the abdomen are less prominent
than in M.centuncularis and the hairs on T6
are flattened against the body rather than
being erect. Males are also very similar to
M.centuncularis and need microscopic
examination of the sternites to separate. They
have more reddish apical tarsal segments (SF).
Habitat Found in areas of flowery grassland
with scrub, including mature dunes such as
Scolt Head and Winterton. It also occurs in
woodland rides including Swanton Novers
Great Wood and shrubby heathland such as
Kelling Heath.
Megachile versicolor
4
3
2
1
0
9
8
2000 – 2014
1980 – 1999
Pre 1980
5
6
7
8
9
0
1
2
3
4
5
Flowers visited Alkanet, Bird’s-foot trefoil,
Meadow Vetchling, Spear Thistle.
Nesting Usually uses hollow stems (SF).
Megachile versicolor female on Spear Thistle.
Kelling Heath 15th August 2011.
Megachile versicolor (probably) male on
Alkanet. Kelling Heath 29th June 2013
Flight times Late May-August
Distribution Widespread but not common.
Parasites Coelioxys inermis is known to be a
cleptoparasite.
Megachile willughbiella
Females are large and broad with brownish
hair. They differ from M. maritima in
generally having less dark hair on the thorax
and abdomen. Both have erect hairs on T6.
The scopa of M. willughbiella is pale orange
but there are black hairs around the edge, and
on the last two segments, visible from above.
M. ligniseca differs in usually being larger with
flat hairs on T6 with a notch at the end, and
has few or no black hairs on the end or edge
of the scopa. Males have a modified front
tibia and tarsus, similar to that of male M.
maritima but not so large and they lack a
swollen hind tibia. The hair colour of the
upper parts of the body is ginger-brown.
Flight times June-September
Distribution Widespread and fairly common.
Megachile willughbiella
4
3
2
1
0
9
8
2000 – 2014
1980 – 1999
Pre 1980
5
6
7
8
9
0
1
2
3
4
5
Habitat Heathland, commons, gardens, river
valleys, Breckland.
Flowers visited Bird’s-foot Trefoil, Bramble,
Garden Sweet Pea, Harebell, Everlasting Pea,
garden Speedwell, , Field Scabious.
Nesting Uses a wide variety of cavities (SF).
Parasites Coelioxyx spp.
Megachile willughbiella female on garden
Sweet Pea. Weybourne 20th July 2012.
Megachile willughbiella male on garden
Speedwell. East Ruston Vicarage Garden 20th
June 2010.