| clinal differentiation and putative hybridization in a contact zone of pinus ponderosa and p. arizonica (pinaceae). | the widely distributed pinus subsection ponderosae is a species complex that has a transition zone among taxa in the southwestern united states. in southern arizona and new mexico at least two recognized taxa, pinus ponderosa var. scopulorum and pinus arizonica or p. ponderosa var. arizonica, are known to coexist in close proximity. in this study, we report the existence of populations where the taxa are sympatric. one of the key characteristics distinguishing taxa is the number of needles per f ... | 2001 | 11410469 |
| needle cell elongation and maturation timing derived from pine needle cellulose delta18o. | estimates of the timing of pinus arizonica engelm. needle development in 1998 and 1999 were derived from the leaf-cellulose delta18o of weekly growth increments. significant correlations were noted between time series of local humidity and leaf-cellulose delta18o for needles growing near tucson, arizona. correlations with temperature were also significant, but much lower, suggesting these variations in cellulose delta18o were determined mostly by changes in humidity. the timing of all significan ... | 2006 | 17086748 |
| spatial pattern of allozyme variation in a contact zone of pinus ponderosa and p. arizonica (pinaceae). | the spatial distribution of genotypes for nine polymorphic allozyme loci was examined in a contact zone between pinus ponderosa var. scopulorum and another tree regarded as either a separate species, pinus arizonica, or variety, pinus ponderosa var. arizonica, in southern arizona. previous work had identified a steep elevational cline for a key taxonomic trait, number of leaf-needles per fascicle, on the south slope of mt. lemmon. the present results indicate that the taxa are not fully interbre ... | 2003 | 21659077 |
| electrophysiological and behavioral responses of the bark beetle dendroctonus rhizophagus to volatiles from host pines and conspecifics. | the bark beetle dendroctonus rhizophagus is endemic to northwestern mexico where it kills immature pines < 3 m tall. we report the first investigation of the chemical ecology of this pest of forest regeneration. we used gc-ead to assess olfactory sensitivity of this species to volatile compounds from: resin of a major host, pinus arizonica; mid/hindguts of single, gallery-initiating females; and mate-paired males within galleries of attacked host trees in the field. antennae of both sexes respon ... | 2012 | 22544334 |
| a new genus of pine-feeding cochylina from the western united states and northern mexico (lepidoptera: tortricidae: euliini). | eupinivora, new genus, is described and illustrated from the montane regions of western united states (nevada, utah, wyoming, colorado, arizona, new mexico, and texas) and mexico (nuevo león, durango, and estado de mexico). as presently defined, the genus includes seven species: e. ponderosae, n. sp. (usa: arizona) (type species); e angulicosta, n. sp. (mexico: nuevo león); e. albolineana, n. sp. (mexico: durango); e. thaumantias (razowski, 1994), n. comb. (mexico: estado de mexico); e. hamartop ... | 2013 | 26000417 |