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Dear All, Aug 23, 2013
The first samples that I brought in included one that was much =
smaller than the rest (which somehow got lost later) and running an =
unpointed one through a Scolytid key (Bright 1976) led to Xyleborus and =
the obsevation that males are much smaller and seldom collected So this =
gave me an incentive to bring in a sample of wood and expose some =
chambers with tools more subtle than a pole axe.
Better dimensions of two chambers were as follows, neither following =
a radius exactly; xylem diameter 17 cm:
Entrance/exit hole diameter; 1mm, 1mm
Xylem surface to chamber start; 5mm, 4mm
Chamber dimensions (maximum)/
Radial; 30mm, 33mm
Axial; 14mm, 15mm
Tangential; 1.5mm, 1.8mm
These chamber were each packed with >60 beetles but some may have =
been just exoskeletons. Being intent on finding males (5 putative from 3 =
chanbers (the one I examined appears to be an exoskeleton) I just =
brushed larvae aside and did not record any ratios of pale beetles =
(recently eclosed) to dark or think to look for pupae.
I think the beetle is Xyloborinus saxeseni (Ratzeburg) [Formerly =
Xyleborus saxeseni (Ratzeburg).
Yt, Dave Webster, Kentville
----- Original Message -----=20
From: David & Alison Webster=20
To: NatureNS@chebucto.ns.ca=20
Sent: Sunday, August 18, 2013 9:50 PM
Subject: Dec 2010 Populus windfall
=20
Dear All, Aug 18, 2013
Today I chunked and split part of two Populus tremuloides (Poplar) =
windfalls in North Alton; Dec 2010 vintage. <snip>
The smaller tree had some wood rot low down when it went over, to =
judge from the way the trunk split near the ground, but most was sound =
but discolored except for one small length where the inner bark was wet =
and had started to decay; tiny elongate Scolytidae (pronotum slightly =
ovate in dorsal view and half as long as elytra) were present in this =
section in envelope shaped chambers in the sapwood, dimensions based on =
two that happened to fall on a split estimated to be 2-4 mm tangential, =
1 cm radial and 1.5 cm axial accessed by a 2 mm diameter horizontal hole =
near the middle. I don't recall having seen these previously (have split =
about 60 cord of Poplar here). This tree, to judge from the dry =
condition of most bark, was dead or nearly dead when it went over.=20
Yt, Dave Webster, Kentville
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<META content=3D"text/html; charset=3Diso-8859-1" =
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<META name=3DGENERATOR content=3D"MSHTML 8.00.6001.23515">
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<BODY bgColor=3D#ffffff>
<DIV>
<DIV>Dear All, =20
Aug 23, 2013</DIV>
<DIV> The first samples that I brought in included one =
that=20
was much smaller than the rest (which somehow got lost later) and =
running an=20
unpointed one through a Scolytid key (Bright 1976) led to Xyleborus and =
the=20
obsevation that males are much smaller and seldom collected So this gave =
me an=20
incentive to bring in a sample of wood and expose some chambers =
with tools=20
more subtle than a pole axe.</DIV>
<DIV> </DIV>
<DIV> Better dimensions of two chambers were as =
follows,=20
neither following a radius exactly; xylem diameter 17 cm:</DIV>
<DIV>Entrance/exit hole diameter; 1mm, 1mm</DIV>
<DIV>Xylem surface to chamber start; 5mm, 4mm</DIV>
<DIV>Chamber dimensions (maximum)/</DIV>
<DIV>Radial; 30mm, 33mm</DIV>
<DIV>Axial; 14mm, 15mm</DIV>
<DIV>Tangential; 1.5mm, 1.8mm</DIV>
<DIV> </DIV>
<DIV> These chamber were each packed with >60 =
beetles but=20
some may have been just exoskeletons. Being intent on finding males (5 =
putative=20
from 3 chanbers (the one I examined appears to be an exoskeleton) I just =
brushed=20
larvae aside and did not record any ratios of pale =
beetles (recently=20
eclosed) to dark or think to look for pupae.</DIV>
<DIV> </DIV>
<DIV> I think the beetle is <EM>Xyloborinus =
saxeseni</EM>=20
(Ratzeburg) [Formerly <EM>Xyleborus saxeseni</EM> (Ratzeburg).</DIV>
<DIV> </DIV>
<DIV>Yt, Dave Webster, Kentville</DIV>
<DIV> </DIV></DIV>
<DIV style=3D"FONT: 10pt arial">----- Original Message -----=20
<DIV style=3D"BACKGROUND: #e4e4e4; font-color: black"><B>From:</B> <A=20
title=3Ddwebster@glinx.com href=3D"mailto:dwebster@glinx.com">David =
& Alison=20
Webster</A> </DIV>
<DIV><B>To:</B> <A title=3DNatureNS@chebucto.ns.ca=20
href=3D"mailto:NatureNS@chebucto.ns.ca">NatureNS@chebucto.ns.ca</A> =
</DIV>
<DIV><B>Sent:</B> Sunday, August 18, 2013 9:50 PM</DIV>
<DIV><B>Subject:</B> Dec 2010 Populus windfall</DIV></DIV>
<DIV> </DIV>
<DIV> <BR></DIV>
<DIV>Dear All, =20
=
Aug=20
18, 2013</DIV>
<DIV> Today I chunked and split part of two =
<EM>Populus=20
tremuloides </EM>(Poplar) windfalls in North Alton; Dec 2010 =
vintage.=20
<snip></DIV>
<DIV> The smaller tree had some wood rot low down when =
it went=20
over, to judge from the way the trunk split near the ground, but most =
was sound=20
but discolored except for one small length where the inner bark was wet =
and had=20
started to decay; tiny elongate Scolytidae (pronotum slightly ovate in =
dorsal=20
view and half as long as elytra) were present in this section in =
envelope shaped=20
chambers in the sapwood, dimensions based on two that happened to fall =
on a=20
split estimated to be 2-4 mm tangential, 1 cm radial and 1.5 cm axial =
accessed=20
by a 2 mm diameter horizontal hole near the middle. I don't recall =
having seen=20
these previously (have split about 60 cord of Poplar here). This tree, =
to judge=20
from the dry condition of most bark, was dead or nearly dead when it =
went=20
over. </DIV>
<DIV> </DIV>
<DIV>Yt, Dave Webster, Kentville</DIV>
<DIV> </DIV></BODY></HTML>
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