Ad can employ both tactics [46]. Nonetheless, we observed that the larval cocoons may well represent reasonably great, even though not absolute, protection against external ice. In our assay, only 25 of cocooned larvae froze, whilst one hundred of “naked” larvae froze. This observation raises the question of just how much the tactic of freezetolerance is relevant beneath field conditions, where only cocooned larvae take place. At the moment, we don’t know. ItFigure 8. Cold tolerance. Survival at subzero temperatures in supercooled and partially frozen states within the fieldsampled caterpillars of Cydia pomonella in the course of 2010/2011. Each point may be the percentage of survivors inside a sample of n larvae (n = flanking quantity). Supercooled larvae had been exposed either to 25uC for 14 d or to 215uC for 7 d. Partially frozen larvae were exposed to 25uC for 1 h. doi:10.1371/journal.pone.0061745.gpopulations prefer overwintering web-sites within the buffered microhabitat from the litter layer (see Fig. S1 for temperature variations in between the two microhabitats). We mounted the cardboard bands on several hundred trees in the course of this study.3-Bromo-1-naphthoic acid custom synthesis All trees (and quite a few more in their vicinity) had been cautiously inspected for diapausing larvae before mounting the bands and throughout the winter samplings at the same time.Difluoroacetic anhydride supplier Despite this effort, we identified many specimens on old trees with deep scars in their bark or with loose bark scales.PMID:23715856 Our field observations contrast with information collected by Canadian authors [15,16] suggesting that overwintering web pages below bark are preferred more than the litter layer and that survival within the litter layer is fairly low [13,14]. Such discrepancy amongst our and Canadian information could possibly be triggered partly by differences in overwintering behavior between the distant populations of C. pomonella, and partly by differences inside the “quality” of respective overwintering web sites involving the two countries. Surprisingly, the same Canadian authors reach a robust consensus that bird predation causes incredibly high winter mortality (close to one hundred ) of codling moth larvae overwintering on trees [94]. Obviously, the question of preference for overwintering website needs extra field observations and tests. At least for South Bohemian populations of C.Table 3. Winter survival in caterpillars of Cydia pomonella exposed to seminatural circumstances.Conditionsa from three Oct 2010 to five Jan 2011 (i) (ii) (iii) (iv) (v)aGroup(n )Survival from 5 Jan 2011to 10 Mar 2011 outside, litter outside, tree lab, constant 0uC lab, 12 h 10uC/12 h 0uC lab, 12 h 0uC/12 h 210uC [ ] 86.1 83.6 72.0 99.0 91.151 159 50 97outdoor, litter outside, tree outside, tree outdoor, tree outside, treeLaboratoryreared caterpillars had been utilized for this experiment. They have been steadily coldacclimated before transfer outdoors on three October 2010. Groups (i) and (ii) remained outdoors for the entire winter. Groups (iii ) had been moved back towards the laboratory on five January 2011 and exposed to simulated winter situations in incubators (under continuous darkness). All groups have been moved to continuous 25uC on ten March 2011 to verify their survival (pupation). See text for much more facts. doi:10.1371/journal.pone.0061745.tPLOS A single | www.plosone.orgCold Tolerance in Codling Mothis clear, however, that both within the litter layer and on tree trunks the probability that an immobile cocooned larva comes in touch with external ice crystals (snow, hoarfrost, ice coatings on bark) is rather higher. Hence, the capacity for freezetolerance can maybe be thought of when it comes to ecological/evolutionary.