Mechanisms of truffle detection by northern flying squirrels

2001 ◽  
Vol 79 (6) ◽  
pp. 1007-1015 ◽  
Author(s):  
Sanjay Pyare ◽  
William S Longland

The objective of this study was to evaluate how northern flying squirrels (Glaucomys sabrinus) locate truffles (Gautieria monticola), a subterranean and ephemeral but primary food source. Thus, we evaluated the importance of three factors to the foraging behavior of northern flying squirrels: (i) olfactory chemicals that emanate from truffles; (ii) the presence of coarse woody debris (decaying logs), which are often associated with fungi; and (iii) we explored the potential role animal memory could play in truffle detection as well. In a foraging arena, squirrels successfully retrieved buried truffles that lacked aboveground cues in 19 of 30 trials and failed to search near treatments that lacked truffles altogether, confirming the importance of olfaction to squirrel foraging. However, squirrels also retrieved truffles that were associated most frequently with surface logs (27 of 30). In addition, the initial detection rate of the truffle + log treatment was significantly greater than the truffle-only treatment. Thus, although squirrels search for truffles primarily using olfaction, they may also benefit by searching near coarse woody debris on the forest floor as an aboveground cue to truffle locations. In addition, because 82% of Sierra Nevada truffle-fruiting locations that were marked in 1996 yielded truffles again the following 2 years, mycophagous animals like northern flying squirrels may benefit by memorizing fruiting locations and foraging at these same locations from year to year.

2005 ◽  
Vol 83 (8) ◽  
pp. 1015-1020 ◽  
Author(s):  
Marc D Meyer ◽  
Malcolm P North

We compared the abundance, diversity, and composition of truffles in riparian and upland areas within a mixed-conifer forest of the Sierra Nevada of California. We sampled for truffles in a single watershed over two seasons (spring and summer) and 4 years to determine whether truffles were more abundant and diverse in riparian than upland sites in old-growth, mixed-conifer forest. Truffle frequency, biomass, and species richness were greater in riparian sites than in upland sites in both spring and summer samples. Species composition of truffles also was different between sites, with nine and one species found exclusively in riparian and upland sites, respectively. Distance between the center of truffle plots to logs and trees was lower and soil moisture was greater in riparian sites compared with upland sites, suggesting that log density, tree proximity, and soil moisture may influence truffle production in these habitats. Our study underscores the importance of riparian areas for truffles, a primary food source for northern flying squirrels (Glaucomys sabrinus) in the Sierra Nevada of California.Key words: truffles, riparian, Sierra Nevada.


2002 ◽  
Vol 32 (6) ◽  
pp. 1016-1024 ◽  
Author(s):  
Sanjay Pyare ◽  
William S Longland

During 1997-1998, we investigated the influence of both the relative abundance of truffles, preferred food items, and microhabitat structure on the occurrence of northern flying squirrels (Glaucomys sabrinus Shaw) in old-growth forest habitat of the Sierra Nevada Range, U.S.A. Following live-trapping sessions, we searched the forest floor for truffle diggings and sampled the soil for truffles. Diggings were more abundant where flying squirrels were captured, suggesting squirrels were active near areas of the forest floor where truffles had recently been excavated. The frequency of sampling plots with truffles was higher where squirrels were captured, further suggesting preferences for microhabitats where truffles were more abundant. We also measured 15 microhabitat variables at trap stations to evaluate the influence of aboveground microhabitat characteristics on squirrel occurrence. Results indicated that flying squirrels preferred microhabitats with understory cover, which may minimize predation from aerial predators like spotted owls (Strix occidentalis Merriam). Neither abundance of coarse woody debris, a feature conducive to fungal growth, nor the abundance of potential nesting sites (i.e., snags) measurably influenced squirrel occurrence. While various aboveground forest-microhabitat characteristics affect the use of old-growth forests by flying squirrels, these animals refine their use of these forests based on fine-scale changes in the availability of a highly preferred and ephemeral food item.


2005 ◽  
Vol 83 (12) ◽  
pp. 1581-1589 ◽  
Author(s):  
Marc D Meyer ◽  
Malcolm P North ◽  
Douglas A Kelt

The diets of a fungal specialist, northern flying squirrel (Glaucomys sabrinus (Shaw, 1801)), and a dietary generalist, lodgepole chipmunk (Neotamias speciosus (Merriam, 1890)), were examined in the old-growth, mixed-conifer forest at the Teakettle Experimental Forest in California's southern Sierra Nevada. Spores of fungi were identified from fecal pellets collected from both species during spring and summer of 1999 through 2002. Frequency of fungi in the diets of both squirrel species was consistently high across all seasons and years of study. Overall, G. sabrinus diets contained about 30% greater richness and evenness of fungal taxa than N. speciosus diets. There were no seasonal differences in richness and evenness of fungal taxa in squirrel diets. Richness of fungal taxa in diets was positively correlated with hypogeous sporocarp biomass and rainfall from June through August for N. speciosus but not for G. sabrinus. Dietary overlap between G. sabrinus and N. speciosus was high with respect to the most frequently consumed fungal taxa, although Gautieria and Gastroboletus were consumed in greater proportions by G. sabrinus than N. speciosus. Our results indicate that in the southern Sierra Nevada both G. sabrinus and N. speciosus were frequent consumers of a similar, diverse assemblage of fungal taxa and that consumption was proportional to seasonal differences in availability. For the more strongly mycophagist G. sabrinus, however, diet had a greater proportion of select fungal taxa and avoidance of less desirable taxa.


1985 ◽  
Vol 63 (5) ◽  
pp. 1084-1088 ◽  
Author(s):  
Zane Maser ◽  
Chris Maser ◽  
James M. Trappe

Digestive tracts of 91 northern flying squirrels (Glaucomys sabrinus) were analyzed for food items; 28 were from northwestern Oregon and 63 from northeastern Oregon. Ninety percent or more of the ingested materials were fungi and lichens, including 20 genera of hypogeous fungi. The northern flying squirrel, in using hypogeous fungi as a major food source, is an important nocturnal disperser of the spores. In Oregon coniferous forests, these fungi are obligatory ectomycorrhizal symbionts with the trees in which the squirrels live.


2019 ◽  
Vol 394 ◽  
pp. 44-52 ◽  
Author(s):  
Stephanie E. Trapp ◽  
Casey C. Day ◽  
Elizabeth A. Flaherty ◽  
Patrick A. Zollner ◽  
Winston P. Smith

2011 ◽  
Vol 7 (4) ◽  
pp. 168-173 ◽  
Author(s):  
A-Ram Yang ◽  
Nam Jin Noh ◽  
Sue Kyoung Lee ◽  
Tae Kyung Yoon ◽  
Choonsig Kim ◽  
...  

1993 ◽  
Vol 71 (3) ◽  
pp. 660-663 ◽  
Author(s):  
Daniel K. Rosenberg ◽  
Robert G. Anthony

We described trapping mortality rates of northern flying squirrel (Glaucomys sabrinus) populations in western Oregon, U.S.A., and evaluated the effects of sex, age, body mass, and number of times an individual was recaptured on these rates. Although the overall trapping mortality rates were relatively low (7%) during 16–21 day trapping sessions, we observed differential mortality rates among the sex and age cohorts. The order of mortality rates was: juvenile females (32.3%) > juvenile males (11.1%) > adult females (5.1%) = adult males (4.1%). Overall trapping mortality rates were not affected by the number of times an individual was captured. We hypothesize that the differences we found were due to extrinsic factors (weather-related) acting on differential behavioral responses to trapping and thresholds of stress an animal can tolerate.


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