2494 M Motile References collected extensively from Russia, including Sibe- ria and Russia’s (at the time) possessions of Alaska Barlow HS (1982) An introduction to the moths of South and California. As a colonel in the military, he had East Asia. Malayan Naturalist Society, Kuala Lumpur, unusual access to travel, and took full advantage of Malaysia, 305 pp, 50 pl his journeys, collecting and studying Coleoptera in Common IFB (1990) Moths of Australia. Melbourne Univer- sity Press, Carlton, Australia, 535 pp, 32 pl Europe, North Africa, and much of North America Covell CV Jr, (1984) A field guide to the moths of eastern in addition to the locations previously mentioned. North America. Houghton Mifflin, Boston, MA, 496 pp, Indeed, it is sometimes stated that his collecting 64 pl trips were a cover for military intelligence. He also Dominick RB, Hodges RW, Dominick T, Edwards CR, Hodges ER (eds) (1971) – The moths of America north of Mex- processed enormous amounts of material collected ico, including Greenland. Wedge Entomological Foun- by others. Motschulsky was a strong-illed, inde- dation, Washington, DC, 27 fasc pendent, and controversial individual. He was pos- Hering EM (1951) Biology of the leaf miners. W. Junk, The sessive, superficial with his descriptions, rough on Hague, The Netherlands, 420 pp, 2 pl Holloway JD, Kibby G, Peggie D (2001) The families of Male- specimens, and unconventional with his mounting sian moths and butterflies. E. J. Brill, Leiden, The Neth- techniques. This led him to clash with other coleop- erlands, 455 pp, 8 pl terists of the time, particularly Kraatz. He died June Inoue H, Sugi S, Kuroko H, Moriuti S, Kawabe A (1982) Moths of Japan. Kodansha, Tokyo, Japan, 2 vol, 392 pl 5, 1871, at Simferopol, Crimea, Russia. Krenek V (2000) Small moths of Europe. Cesky Tesín, Czech Rep, 174 pp Pinhey EGC (1975) Moths of Southern Africa. Tafelberg, References Capetown, South Africa, 273 pp, 63 pl Robinson GS, Tuck KR, Shaffer M (1994) A field guide to the smaller moths of south-east Asia. Malaysian Naturalist Essig EO (1931) A history of entomology. The Macmillan Society, Kuala Lumpur, Malaysia, 309 pp, 32 pl Company, New York, 1029 pp Watson A, Whalley PES (1975) The dictionary of butterflies Herman LH (2001) Motschulsky, Victor Ivanovich. Bull Am and moths in color. McGraw Hill, New York, NY, 296 pp, Mus Nat Hist 265:110–112 144 pl Young M (1997) The natural history of moths. T. & A.D. Poyser, London, United Kingdom, 271 pp, 16 pl Mountain Midges Motile Members of the family Deuterophlebiidae (order Diptera). Active. Able to move freely. Flies Motor Neurons Mountain Pine Beetle, Neurons associated with the central nervous sys- Dendroctonus ponderosae tem that transmit information to muscles and (Coleoptera: Curculionidae, glands. Scolytinae) barbara bentz Motschulsky, Victor Ivanovich USDA Forest Service, Logan, UT, USA Victor Motschulsky was born in 1810 in Russia, The mountain pine beetle, Dendroctonus pondero- and became one of the most famous Russian ento- sae Hopkins, is considered one of the most eco- mologists and greatest coleopterists of his time. He nomically important insect species in coniferous Mountain Pine Beetle, Dendroctonus ponderosae (Coleoptera: Curculionidae, Scolytinae) M 2495 forests of western North America. Adult beetles other mountain pine beetles on the tree. Aggrega- are capable of successfully reproducing in at least tion pheromones enable mountain pine beetles to 12 North American species of Pinus (Pineacea) overcome the defenses of large, vigorous host trees from southern British Columbia to northern Baja by rapid and highly concentrated attacks. In this Mexico. Mountain pine beetle adults attack live manner, mountain pine beetles are functionally trees, and typically must kill the host for success- able to expand their own food supply. Larger trees ful reproduction. Population outbreaks are most require more adults to overcome the tree resin common in a few selected host species, such as defensives, but also produce a larger number of lodgepole pine (P. contorta), ponderosa pine brood the following generation for continued tree (P. ponderosa), western white pine (P. monticola), attack. Because a single tree is a finite resource, whitebark pine (P. albicaulis), and sugar pine pheromones are also produced which interrupt (P. lambertiana), which often grow in relatively the aggregation of adults on a tree. The interrup- homogeneous groups over large acreages. Moun- tive aggregation pheromones direct incoming tain pine beetles typically attack older lodgepole adults to unoccupied portions of the tree under and whitebark pine (e.g., greater than 80 years), attack, and also to nearby host trees, thereby reduc- while younger ponderosa, western white, and ing competition for resources within a single tree. sugar pine can also be attacked. Trees that are In this manner, during an outbreak, thousands of stressed by factors such as overcrowding, water, trees can be attacked and killed in a single year. and pathogens are especially vulnerable. Once inside a new host tree, adults mate and The lifecycle of the mountain pine beetle is eggs are laid individually on each side of galleries highly dependent upon temperature. Commonly, excavated vertically in the phloem. Phloem is the populations are univoltine, although at higher ele- inner tissue layer just below the outer bark which vations where average temperatures are colder, 2 translocates carbohydrates up and down the tree. and sometimes 3 years are required to complete a Mountain pine beetle larvae feed horizontally in generation. Adult beetles emerge from host trees the phloem, cutting off nutrient translocation, and disperse to new hosts in the warm summer thereby killing the host tree. Larval development months when temperatures are above 15.5°C. rate, which is highly dependent on temperature, Although timing of emergence will vary from dictates the life stages present during the winter. year to year depending on beetle development Available evidence indicates that the mountain and temperature, peak adult emergence typically pine beetle does not diapause, and all larval life occurs within a 2–3 week time span. Rapid and stages may be found overwintering under the bark synchronous emergence of the population is of host trees. The larvae, which are intolerant of essential for mountain pine beetle success in over- freezing temperatures, survive low temperatures coming the resinous defenses of healthy host trees. by supercooling. Populations in Idaho have been Adult dispersal involves movement within an found to survive temperatures as low as −35°C. infested patch of trees, movement between infested Mortality due to cold temperatures is usually patches of trees, and movement out of the imme- greatest during the spring and fall months when diate area for initiation of new patches. Long range larvae may not be appropriately acclimated to dra- dispersal to new areas is often aided by wind cur- matic swings in temperature. Woodpeckers, clerid rents, whereas local dispersal is directed by aggre- beetles (Enoclerus spp., Thanasimus spp.), and par- gation pheromones, compounds released when asitic wasps are also the cause of a small amount of adult beetles attack and feed on new host trees. mountain pine beetle mortality, mostly at endemic Monoterpenes, which are major constituents of population levels. pine resin, are converted by adult beetles to com- Pupation occurs in the early summer followed pounds which, when released, act to aggregate by a teneral adult stage during which the new 2496 M Mountain Pine Beetle, Dendroctonus ponderosae (Coleoptera: Curculionidae, Scolytinae) adults feed on a diverse flora of microbial symbi- growth. A mosaic of vegetation types across a onts including fungi (Ophiostoma spp.) and yeasts landscape, partitioned by age and host and non- found within the pupal chamber. During this feed- host species, may also help to reduce large scale, ing period, the microorganisms are acquired in widespread mortality. the mycangia, a specialized structure of the integ- Options for management of mountain pine ument. When the adult beetle emerges from the beetle populations depend on the specific land use host tree for dispersal to a new tree, the fungi and objectives. Forested areas targeted for timber pro- yeasts are carried inside the mycangia and inocu- duction can be silviculturally treated to facilitate lated into the phloem of the new host. Although reduced susceptibility to mountain pine beetle the role of Ophiostoma spp. in mountain pine outbreaks. Many areas designated as wilderness, beetle population dynamics are not fully under- however, are managed as natural areas and timber stood, at least one species appears to be beneficial harvest is not a major objective. Within these areas to population success, while detrimental effects the historical role of the mountain pine beetle in are attributed to another species. Following matu- forest ecosystems may be emphasized. Mountain ration feeding in the teneral adult stage, new adults pine beetle populations, which are native to western emerge from the dead trees to disperse, attack new North America, have evolved with their pine hosts live host trees, and begin the cycle again. and are significant components of healthy, func- Given appropriate weather and stand condi- tioning ecosystems. In particular, the mountain tions, populations of mountain pine beetles are pine beetle and fire are considered important dis- capable of attacking and killing hundreds of thou- turbance agents favoring the regeneration of lodge- sands of trees in a few years. This magnitude of pole pine. While tree death is a difficult concept for mortality can disrupt forest management plans, humans, it is a normal step in the rejuvenation and recreation, watershed, wildlife, and timber pro- succession of forest ecosystems, and the mountain duction. In areas of high value, such as forest pine beetle is an important part of this process. campgrounds and ski areas, direct control tactics Bark Beetles in the Genus Dendroctonus such as insecticides are often used to temporarily reduce mountain pine beetle caused mortality.