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.
Hairy and Downy Woodpecker Attacks on Cocoons of Urban Hyalophora cecropia and Other Saturniids (Lepidoptera)
Observations in the field and experiments with a caged bird show that both the downy and hairy woodpeckers prey upon cecropia pupae, Hyalophora cecropia (L.), leaving an injury which is indistinguishable from that found on cocoons collected in Champaign and Urbana, Illinois. Cocoons of H. promethea (Drury) and Antheraea polyphemus (Cramer) may show similar injuries.
The Influence of Small Mammals and Other Factors Upon the Larch Sawfly Survival
This paper presents the results of a series of quantitative studies and experiments concerning the factors that influence mortality of the larch sawfly, Lygaeonematus erichsonii , in the cocoon stage. Facts are presented to show that the physical conditions that exist in the sphagnum moss in tamarack swamps are much more favorable for hibernation of the sawflies than are the conditions that are to be found under tamarack on high ground.

Of the biotic factors that operate to reduce the numbers of the sawfly in the cocoon stage small mammals, particularly mice, play a much more important role than do the insect parasites and fungus diseases.