Recent Trends in Forest Entomology

Abstract

The past decade and a half has been a fascinating and stimulating period in the development of forest entomology. This ctuthor has seen it increase from a primarily observational science to a field which contributes to many disciplines. Most of the climatic concepts advanced by Wellington (130), the current studies on principles of predation by Holling (43, 44), the classic population dynamics studies on the spruce budworm reviewed by Morris (75), the newly recognized importance and application of behavioral differ ences in population dynamics studies (131), and new application of computer techniques (75, 127, 128) were based on forest entomological work, and forest entomologists have had considerable influence on their development.The widening scope of forest entomology is also reflected in other recent reviews and major publications. The fields of ecology (35, 94), sampling (74), biological control (5, 61), chemical control (7, 30), systematics (46, 47, 137), physiology and behavior (31, 132), and various forestry techniques such as photogrammetry (39, 40,129), mensuration, and tree growth studies (76), have all been advanced through the efforts of scientists working on forest insect problems. One of the most monumental surveys of pests of a particular crop is moving into its third volume-The Forest Lepidoptera of CanadaL-which, hopefully, wi11 lead to comparable lists for all forest insects.These various studies indicate a strong trend toward specialization and as pointed out by Balch (6) this emphasizes the need for more integrated studies. There are many such programs now in existence in forest entomo logical work and the need for the synecological approach is being recognized.

Coevolution of Mutualism Between Ants and Acacias in Central America

“…There is a growing body of literature which strongly suggests that the chemical and microphysical properties of the vegetative parts of plants may be evolved in partial or entire response to the use of the plants as energy sources and substrates by insects (see Southwood, 1961;Beck, 1965;Stark, 1965;and Ehrlich and Raven, 1965;and included references). It appears that the swollen-thorn acacias have substituted the abilities of the obligate acacia-ants for many of the physical and chemical traits that other acacias use in their defense; this is strong evidence that these properties exist.…”

Forest Health in North America: Some Perspectives on Actual and Potential Roles of Climate and Air Pollution

“…Poor soil nutrition, including low Ca, P, K, and Mg has been recognized as a predisposing factor is sensitivity of Douglas fir to spruce budworm attack (Kemp and Moody, 1984). Stark (1965) lists 20 studies in which forest fertilization increases resistance of pines to insect attacks. Interestingly in 10 of 12 studies in which Ca was added alone or as a component of fertilization, reduced density or increased mortality of insect larvae was noted.…”

“…Interestingly in 10 of 12 studies in which Ca was added alone or as a component of fertilization, reduced density or increased mortality of insect larvae was noted. Radiochemical studies suggest that Ca may be toxic to insects (see Stark, 1965). The loss and/ or reduced availability of exchangeable soil Ca from soil reserves in response to long term deposition of S and N, thus has important implications for long term forest growth and forest ecosystem health.…”

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“…Evidence is rapidly accumulating to support the idea that the primary role of socalled "secondary plant substances" or "waste products" is in influencing intraand interspecific encounters between the plant and other organisms (e.g., natural herbicides-allelopathy, natural insecticides or repellents, natural fungicides; Muller, 1966;Janzen, 1969;Fraenkel, 1959;Brower et al, 1964Brower et al, , 1967Kaplanis et al, 1967;Ben-Aziz, 1967;Farnsworth, 1968;Feeny, 1968;Feeny and Bostock, 1968;Beck, 1965;Stark, 1965;Applebaum, 1964;Applebaum et al, 1965;Cranmer and Turner, 1967;Brown, 1967, etc. ), despite comments to the effect that they "appear to have no biological role in the SEEDS, PREDATION, AND DISPERSAL 3 plants which produce them" (Leete, 1965).…”