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instance in the genus <i>Ips</i>, that are s Thanks Chris! Eleanor Christopher Majka wrote: > Hi Eleanor, > > On 11-Nov-09, at 9:07 AM, Eleanor Lindsay wrote: > >> I think there are some very distinct regional differences in this >> year's wild food supply. The spruce bark beetle, which I understand >> is native to Nova Scotia and normally kept in check by cold >> winters...) has created quite severe and rapid devastation in some >> parts of the province, in particular the east side of St Margarets >> Bay, (especially Seabright and Glen Margaret), where whole chunks of >> spruce forest have died off in the space of the last 2-3 years and >> also, I believe in parts of Antigonish County and Cape Breton. So >> cones for squirrels, for example, must be severely reduced or non >> existent in these areas. > > In North America the name "spruce bark beetle" is normally applied to > Dendroctonus rufipennis, although in Europe, the name indicates > another species, Ips typographicus. Dendroctonus rufipennis is a > native species in Nova Scotia, indeed it occurs throughout North > America from Alaska to Newfoundland and south into the USA wherever > spruce grow. Although most of the recent attention on the relationship > of climate change to bark beetle infestations has been devoted to the > mountain pine beetle (Dendroctonus ponderosae), there are considerable > similarities between the two species. There are two climate related > effects: > > 1) Prolonged cold temperatures during the winter can kill some of the > overwintering beetles. As we experience climate change, and prolonged > cold snaps in winter become less frequent, this bioregulation > mechanism becomes less effective. For example, studies in the southern > United States on the similar southern pine beetle (Dendroctonus > frontalis) have linked outbreaks there to a warming trend from 1960 to > 2004 of 3.3°C in minimum winter air temperatures. > > 2) Spruce bark beetles normally complete their life cycles in either > one or two years (rarely three, in cold northern regions). As climate > changes and temperatures warm, a greater proportion of beetles can > complete their life cycles in a shorter period of time, leading to > faster turnover and greater utilization of resources (i.e., they chew > through spruce more quickly ;->). > > In other bark beetles, for instance in the genus Ips, that are > sometimes univoltine (i.e., one generation per year), or bivoltine > (two generations per year), warming temperatures mean that a greater > proportion of the population becomes bivoltine, again with the same > consequences: population levels increase and they consume more food > (most bark beetles are cambium feeders, feeding on the inner bark of > trees). > > The USDA Forest Service has a good web page on Dendroctonus rufipennis: > > http://www.na.fs.fed.us/spfo/pubs/fidls/sprucebeetle/sprucebeetle.htm > > Cheers! > > Chris > > > Christopher Majka <c.majka@ns.sympatico.ca> | Halifax, Nova Scotia, > Canada > > * Research Associate: Nova Scotia Museum | > http://museum.gov.ns.ca/mnh/research-asfr.htm > * Review Editor: The Coleopterists Bulletin | http://www.coleopsoc.org/ > * Subject Editor: ZooKeys | > http://pensoftonline.net/zookeys/index.php/journal/index > * Associate Editor: Journal of the Acadian Entomological Society | > http://www.acadianes.org/journal.html > * Editor: Atlantic Canada Coleoptera | > http://www.chebucto.ns.ca/Environment/NHR/atlantic_coleoptera.html > > "Whenever I hear of the capture of rare beetles, I feel like an old > war-horse at the sound of a trumpet." - Charles Darwin > > > ------------------------------------------------------------------------ > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 9.0.704 / Virus Database: 270.14.60/2496 - Release Date: 11/11/09 03:40:00 > >
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