/ ENTOMOLOGY NEWSLETTER ~ Department of Entomology Vo 1. 3, No. 1 University of Minnesota Ma r. 14, 1986 Monarch Migration: IN THIS ISSUE: an Endangered Phenomenon? Articles: Monarch Migration NCB-ESA Meetings by Nancy Read and Marc Epstein New Books Faculty News Few insects are better known in Greetings the U.S. than the monarch butterf 1y. The Frenatae activities monarch (Danaus p1exippus L.) is found Jobs throughout the American continent and has spread through much of the Pacific Next newsletter deadline: Apr. 14 islands, including Australia and New Zealand. Populations in the temperate NCB Meetings Update zones can avoid the vagaries of winter by Va 1 Cervenka weather by migrating to areas with cool but fairly stable conditions, such as . As the NCB-ESA meetings rapidly sheltered coastal areas in California or approach (Mar. 24-27), excitement at the the fir forests in the volcanic moun­ U. of Minn. ;s mounting to a fever tains in Mexico. 'pitch. The Local Arrangements Committee Dr. Lincoln Brower of the Univ. of has been work i ng extra hard and is busy Florida gave a seminar last week on the with last-minute details to make this physiology of the Mexican overwintering conference the best yet. You may want monarch colonies. He and his col leagues to make note of these recent changes and have shown that temperatures are a crit­ announcements: ical factor in survival. The monarchs There has been a change of speakers overwinter in reproductive diapause, and at the student symposium. Carl Barfield if cond i t ions are too warm they may of the University of Florida will be dehydrate or use up their ,1imited nutri­ replacing Grace Goodell, and Florence ent reserves. If conditions are too cold Dunkel will speak in lieu of Delane (even a few degrees below freezing, Welsch. Watch for further addenda to espec i a 11 y if the butterf 1 i es are wet the program. with dew or snow) the exposed monarchs Because of lack of interest coupled wi 11 die. Thus factors affect ing the with high cost, welre sorry to report microclimate of the overwintering habi­ there wi 11 be no "ath 1et i c break II at the tat, such as foliage density, are impor­ Greenway Athletic Club as hoped earlier. tant to monarch survival. However, the outdoor running track and Large populations of monarchs from indoor pool are availible at no cost to the Eastern and Centra 1 U.S. overwinter Hyatt-Regency guests. ;n the high-altitude fir forests in the Mobay Corp. wi 11 be sponsoring Mexican states of Mexico and Michoacan. complimentary breakfast each morning at Colonies in this area have been esti­ the meetings. Check at the registration mated to contain tens of mil lions of table for exact, time and location. monarchs. The butterflies have been Speaking of registration, volun­ shown to return to the same valleys and teers are still needed to help Marion even the same trees each year. However, Brooks-Wal lace and Ron Gardner. when forming these colonies in the fall, Frenatae: the Entomo logy Students I (continued next page) Association will be selling commemora­ tive mugs throughout the meetings, or whi 1e they 1ast! Look for them near Registration, at the Student Mixer, and elsewhere at the meetings. You won't want to leave Minneapolis without one! Speaking of the Student Mixer, plan to attend to meet old fr i ends and make (NCB continued on page 3) page 2 (from prev i ous page) ~"" .. the butterflies avoid clearings and areas th inned by loggers, where the moderat i ng effect of the forest canopy on temperature extremes is reduced. Since 1976 logging dramatically increased near the most extensive Mexi­ can overwintering area. In one heavy logging operat ion tens of thousands of monarchs were killed. Cattle in the area also take their toll, feeding on the butterflies. Human population pressure South American monarchs also migrate, in the area i ncreas i ng 1y threatens the but no other information on the migra­ existence of major overwintering sites. tion or diapause status is avai1ib1e. How much of a threat does th i s Monarch popu 1at ions 'in Centra 1 America habitat destruction pose to the total and a few extreme southern areas of the monarch population? The answer to this U.S. breed continually, and it is as­ primarily depends on whether the mon~ sumed that populations in other tropical archs can successfully overwinter else­ areas do 1ikewise. where. At this time no one knows if the Since very little quantitative work monarchs would move to another over­ has been done on either the eastern or wintering site. Magnetite has been found western U.S. monarch·popu1ations, it is in monarch wings, and the current breed­ . impossible to estimate the impact of ing area is said to be at the center of overwintering site destruction on total strong magnetic fields. If magnetism is population numbers. Given the wide geo­ important in breeding site location, it graphic range of the species and the could be hard to move. diversity of overwintering situations It has been suggested that the West worldwide, the species itself is proba­ Coast monarch population had very few bly not endangered., However, the chance places to overwinter before the spread of overwintering site loss disrupting of Eucalyptus and native Monterey pine the North American monarch's migratory and cyprus (preferred roosting trees) in behaviour is much greater. For this the past century. Currently over 40 reason the International Union for the sites exist, but the largest populations Conservation of Nature (IUCN) has de­ at anyone site are on 1y a hundredth of clared North American monarch migration the size of the Mexican colonies. an "endangered phenomenon ". Evidence from individual sites in Several organizations are working Pacific Grove, California, suggests that together to protect the Mexican over­ once the microclimate of a site is dis­ wintering sites. A national park has turbed, the butterflies will not return been proposed by the Biology Institute to that site. Some, research is currently of the National Autonomous University of underway on potentially disturbed sites Mexico. Pro Mariposa Monarca is a pri­ in Ca 1ifornia. vate association organized to assist the Litt 1e 'i s known about monarch mi­ protection of sites. The Mexican gration in other parts of the world. The Society of Lepidopterists and various Australian monarch populations migrate, government agencies are also working on but they do not congregate in sites as the problem. Since most of the sites large as the Mexican sites. They also are on land held in common by a com­ have a different di apause response, munity, regulating land use or buying according to Dr. Bi 11 Herman of the the land is a complex issue. Special Dept. of Genetics and Cell Biology. In efforts are being made to insure that Dr. Herman's studies of the endocrinolo­ people in the area have other sources of gy of monarch diapause he has shown income -- such as tourism -- so that that North American monarchs induced economic uses of breeding site areas can into diapause in the fall wi 11 not re­ be curta i 1ed. produce in warm conditions until after a The general conclusion of Dr. certain period of time. Austrai 1 ian Brower and others working in the field monarchs may appear to be reproductively seems to be that, if you want to see the dormant, but can be induced to reproduce giant overwintering monarch colonies in in warm conditions. It is known that Mexico,go see them soon. page 3 '" (NCB from page 1) New Books a. new ones. It's on us! by Rich Hansen For your danc i ng and 1 i sten i ng enjoyment, the Aristocrats will be play­ The long-awaited "reincarnation" of ing Tuesday night for the Entertainment. W.L. Baker's cl assic and out-of-print Come and relax and let your hair down. Eastern Forest Insects is now availible. Our own department will be very The U.S. Forest Service has recently well-represented at the talks. The list published Insects of Eastern Forests, of those presenting papers or posters edited by A. T. Drooz. This valuable includes D. Andow, V. Cervenka, L. reference contains much of the detailed Cutkomp, D. Davis, S. Duff, K. Flanders, life history and host relationship B. Furga 1 a, R. Gardner, A. Hanafi, R. information contained in Baker's book, Hansen, P. Harein, S. Katovich, H. with appropriate updating, particularly Kulman, recent student J. Loughran, R. in nomenclature and taxonomy. The 'new' Moon, K. Ostlie, E. Radcliffe, D. vo 1ume st ill 1acks insect or damage heys Ragsdale, D. Setiawan, recent student K. and retains the sma 11, black-and-white Sharkey, and B. Subramanyam (Sub i). illustrations of Baker's book. Nonethe­ We are looking forward to seeing less, Insects of Eastern Forests is a all of you, and as the saying goes, be comprehensive reference of value to all there or definitely be square! entomologists. It is available from the Superintendent of Documents, U.S. Govt. Printing Office, for an unknown price Entomology Newsletter is a monthly - (refer to USDA Forest Service Misc. pub 1 i cat i on of the U of MN Dept. of Pub 1. 1426). Entomo logy and Frenatae (Entomo logy A recent publication from the Can­ Student Association). adian Forestry Service can serve as a Editor: Nancy Read. Invaluable Staff: nice complement to Drooz' book. Rich Hansen, Val Cervenka, and anyone Insects harmful to forest trees by R.