Response to cecropia cocoons of Mus musculus and two species of Peromyscus
SummaryIn rural areas cocoons of overwintering Hyalophora cecropia spum close to the ground are opened and the pupae eaten by small mammals, but in urban areas, where cecropia populations are much larger, the cocoons are almost never opened by mammals. Peromyscus leucopus noveboracensis and P. maniculatus bairdii are abundant in rural areas, but are largely replaced by Mus musculus in urban areas. In laboratory experiments P. l. noveboracensis invariably opened cecropia cocoons and ate the pupae. P. m. bairdii were slower to open cecropia cocoons and two of twelve did not open one at all. M. musculus, on the other hand, never opened cecropia cocoons although they gnawed the silk and ate uncovered pupae. Cocoons opened in the laboratory by the two species of Peromyscus cannot be distinguished from each other or from cocoons opened in the field.
THE SELECTION BY CERTAIN SMALL MAMMALS OF DEAD, PARASITIZED, AND HEALTHY PREPUPAE OF THE EUROPEAN PINE SAWFLY, NEODIPRION SERTIFER (GEOFF.)
Caged Sorex cinereus cinereus Kerr, Blarina brevicauda talpoides Gapper, and Peromyscus maniculatus bairdii Hoy and Kenicott opened more cocoons containing healthy, living sawfly prepupae than ones containing prepupae attacked by fungus. In the field and in the laboratory, S.c.cinereus opened more healthy cocoons than cocoons containing parasites. The reverse appeared to be true for B.b.talpoides. P.m.bairdii opened equal numbers of healthy and parasitized cocoons. The more insectivorous animals exhibited the greatest selective ability. Pretreatment to cocoons of one category affected the selective ability. Pretreating P.m.bairdii to fungus cocoons lowered the ability to select healthy cocoons over fungus cocoons. Pretreating animals to healthy cocoons raised the selective ability. Selection occurred in the digging, removing, opening, and eating phases in the search for cocoons. The closer the phase to the consummatory action, the greater was the degree of selection. The selective ability in the first thr...
Novel method for the determination of the methoxyl content in lignin by headspace gas chromatography.
The paper reports on a headspace gas chromatographic (HS-GC) method for the determination of methoxyl in lignin. The method involves the quantitive cleavage of methoxyl with hydroiodic acid (HI) to form methyl iodide in a closed headspace sample vial at 130 °C for 30 min. After HI has been added, the sample is neutralized by injecting a sodium hydroxide solution; the methyl iodide in the vial was determined by HS-GC using a flame ionization detector. The results showed that the method has an excellent measurement precision (RSD < 0.69%) and accuracy (RSD < 3.5%) for the quantification of methoxyl content in lignin. The present method is simple and accurate and can be used for the efficient determination of methoxy1 content in lignin and related materials.