Insect Nutrition Research Articles

Extrafloral Nectar: Entomological Implications

Linnacus created the word “nectary” (nectarium) in 1735 to denote specialized epidermal glands composed of small, thin-walled secretory cells from which nectar is brought to the surface through modified stomata (Fahn 1979). Nectar was defined aptly by Trelease (1879) as “a fluid always sapid, usually sweet, often odorous, which is elaborated in any part of a plant, remaining where formed or making its way to some other part; its raison d'etre being the necessity for the removal of some useless or injurious substance, or for some provision to attract nectar-loving animals to the plant for some definite purpose.” The distinction between floral (nuptial) nectaries and extrafloral (vegetative) nectaries was made by Caspary in 1848 (Fahn 1979). The mutual role of floral nectar in plant pollination and insect nutrition is well known (McGregor 1976). Although extrafloral nectar has been the subject of naturalists' curiosity and hypotheses for more than a century (Bentley 1976), only in recent years have we begun to understand its source, characteristics, functions, and chemical ecology.

Insect Nutrition: An Adaptationist's Perspective

Insect Nutrition: An Adaptationist's Perspective

Insect Physiology Current Topics in Insect Endocrinology and Nutrition Govindan Shaskaran Stanley Friedman J. G. Rodriguez

Insect Physiology Current Topics in Insect Endocrinology and Nutrition Govindan Shaskaran Stanley Friedman J. G. Rodriguez

Current Topics in Insect Endocrinology and Nutrition. A Tribute to Gottfried S. Fraenkel. Govindan Bhaskaran , Stanley Friedman , J. G. Rodriguez

<i>Current Topics in Insect Endocrinology and Nutrition. A Tribute to Gottfried S. Fraenkel</i>. Govindan Bhaskaran , Stanley Friedman , J. G. Rodriguez

Book Notices

BIOLOGY OF INSECT EGGS. In three volumes. By H. E. HintonANNUAL REVIEW OF ENTOMOLOGY. Volume 25. Ed. by T. E. Mittler, F. R. Radosky and V. H. ReshCURRENT TOPICS IN INSECT ENDOCRINOLOGY AND NUTRITION. Edited by G. Bhaskaran, S. Friedman and J. G. RodriquezINSECT THERMOREGULATION. Edited by Bernd HeinrichNEW TECHNOLOGY OF PEST CONTROL. Edited by Carl B. Huffaker

Feeding and Nutrition of Insects Associated with Soybeans. 3. Food Intake, Utilization, and Growth in the Soybean Looper, Pseudoplusia includens1, 2

A study was made of the adequacy of soybeans as food for the soybean looper, Pseudoplusia includens (Walker), based on growth and nutritional analyses using fresh and dry weights of animals and food. Efficiency of conversion of ingested food (ECI) (fresh and dry), efficiency of conversion of digested food (ECD), and approximate digestibility (AD), were computed on a daily basis and by stage of development. The consumption index (CI) and growth rate (GR) were computed on fresh- and dry-weight measurements. The mean relative growth rate (RGR), extensively used in plant-growth analysis, was applied to the data and compared to GR. The RGR was 34% greater than GR, which uses the calculated mean animal weight. The regression of the log-transformed cumulative weight gain on time closely fitted the growth curve in the interval of near-exponential growth. The regression equation gave a good description of the growth pattern during the period of most active feeding. Another method used to define the rates of consumption was the regression of the cumulative weight of food consumed (log-transformed) on time. The effect of the rate of food consumed on growth was measured by fitting linear equations to weight gain and food consumed. The observed differences in the results of growth and nutritional indices, based on fresh and on dry weight, were explained by the variation of the dry-matter content of larvae during development, and on differential feeding by larvae of different ages. Young larvae feed selectively on low-fiber-containing leaf tissues of high digestibility, whereas older larvae feed indiscriminately, ingesting large proportions of high-fiber-content, low-digestibility leaf tissues.

Foods and Feeders: Insect and Mite Nutrition . Significance and Implications in Ecology and Pest Management. Proceedings of a conference, Lexington, Ky., April 1972. J. G. Rodriguez, Ed. North-Holland, Amsterdam, 1972 (U.S. distributor, Elsevier, New York). xiv, 702 pp., illus. $30.

Foods and Feeders: <i>Insect and Mite Nutrition</i> . Significance and Implications in Ecology and Pest Management. Proceedings of a conference, Lexington, Ky., April 1972. J. G. Rodriguez, Ed. North-Holland, Amsterdam, 1972 (U.S. distributor, Elsevier, New York). xiv, 702 pp., illus. $30.

Foods and Feeders: Insect and Mite Nutrition . Significance and Implications in Ecology and Pest Management. Proceedings of a conference, Lexington, Ky., April 1972. J. G. Rodriguez, Ed. North-Holland, Amsterdam, 1972 (U.S. distributor, Elsevier, New York). xiv, 702 pp., illus. $30.

Foods and Feeders: <i>Insect and Mite Nutrition</i> . Significance and Implications in Ecology and Pest Management. Proceedings of a conference, Lexington, Ky., April 1972. J. G. Rodriguez, Ed. North-Holland, Amsterdam, 1972 (U.S. distributor, Elsevier, New York). xiv, 702 pp., illus. $30.

Foods and Feeders. (Book Reviews: Insect and Mite Nutrition. Significance and Implications in Ecology and Pest Management. Proceedings of a conference, Lexington, Ky., April 1972)

Foods and Feeders. (Book Reviews: Insect and Mite Nutrition. Significance and Implications in Ecology and Pest Management. Proceedings of a conference, Lexington, Ky., April 1972)

Insect cell nutrition: emphasis on sterols and fatty acids.

The requirements for, or the utilization of, vitamins, sugars, amino acids, and lipids, as determined with established insect cell lines, are reviewed. Also discussed is the importance of inorganic salt balance and osmotic pressure. Nutrient requirements, as determined in experiments with established cells, are compared to media formulations based on the analysis of insect hemolymphs and to the dietary requirements of insects. It is suggested that culture media formulated in strict agreement with hemolymph analysis may be unnecessarily complex and do not ensure maximum growth.

Self-selection of an optimum diet from a mixture of wheat fractions by the larvae of Tribolium confusum

Tribolium confusum was reared from the beginning of the first instar to the pupa on wheat bran, endosperm or germ or on a 1 : 1 : 1 mixture of these three fractions. The food intake of the larvae reared on the mixture included more or less similar proportions of the three wheat fractions, averaging 1·5 per cent bran, 17·1 per cent endosperm and 81·4 per cent germ. Past work on the nutrition of stored-product insects has involved the assumption that the insects cannot feed selectively from a finely powdered diet. Our findings show that this assumption may not be warranted. The mixed diet supported growth better than any one of the pure fractions or any wheat diet previously tested by us. It was superior to germ, the best of the pure fractions, because it was more digestible and because the digested portion was more efficiently utilized for growth. Endosperm, the poorest diet of the fractions, was highly digestible but was not efficiently utilized. Bran, better than endosperm but inferior to germ, was relatively indigestible although the digested portion was efficiently utilized. Germ was both digestible and efficiently utilized.

Insect Nutrition: Current Developments and Metabolic Implications

Three decade s ago nutritional investigation of insects had developed to the point of describing complete qualitative dietar y requirements of several nonfastidious spe cies that readily accepted chemically defined diets, allowing individually deleted nutrients to be assessed in terms of growth and develop­ ment. The antece dents of this phase of insect nutrition may be traced in earl y reviews (41, 197, 274,275, 299). Subsequent proliferation of studies enabled a recent tabular summary (6) to list nutrient requirements of about forty species, diverse in taxonomy and feeding habit s, and notably including sev­ eral plant-feedin g insects, a category long intractable to dietary manipulation. Such a wealth of consolidatory information affords a substantial basis for generalizing the nutritive needs of the class as a whole. The conclusions, many sti ll valid, may be examined in a sequence of general review (65, 73, 149, 150, 153,248), augmented by specialized discussions of parasitic insects (148), phytophagous insects (45, 105, 282), nutr itional pathology (151), nutrition and resistance to biochemicals (125), silkworms (165, 305), m os­ quitoes (54), grasshoppers (60), Diptera (106), bees (132), and plant-suck­ ing insects (10, 11, 207). Information on bulk digestibility and utilization of natural and artificial foods, scattered throughout the foregoing reviews, was recently summarized and critically discussed (126, 296). The impact of sym­ biotic microorganisms on host nutrition has been surveyed (35, 90, 134), as has the bearing of physical and gustatory attributes of experimental diets on the inter pretation of nutritional studies

Feeding and Nutrition of Insects Associated with Soybeans. 2. Soybean Resistance and Host Preferences of the Mexican Bean Beetle, Epilachna varivestis1

Dual choice tests were used to analyze food preferences by the Mexican bean beetle, Epilachna varivestis Mulsant (Coleoptera: Coccinellidae). Seven series of tests including 26 comparisons of Clark normal, Harosoy normal, and Bragg soybeans with 6 Clark and Harosoy isolines, 9 resistant selections, and 5 other species of legumes were performed. It is suggested that there is no evidence for an influence of leaf pubescence on the acceptance of Clark and Harosoy soybeans. All Clark isolines were preferred to Harosoy normal, regardless of leaf pubescence. The selections Pi's 227,687 and 171,451 were low in the food preference scale indicating a strong nonpreference type of resistance. Pi's 229,358, 243,519, and 81,777 were partially rejected by adult beetles. F1 cross of Bragg × PI 229,358 showed a preference index intermediate between that of the parent lines suggesting a semidominance type of inheritance of the resistance trait. Soybean-associated Mexican bean beetles do not seem to have drastically shifted their food preferences, as they prefer snap and lima beans even under action of possible induction effect of a continuous soybean diet. The paired comparison test seems to be a useful subsidiary bioassay in a breeding program for soybean insect resistance.

Fluorescence Photography in the Quantitative Evaluation of Feeding by Phytophagous Insects

Critical investigations of feeding behavior and nutrition of mandibulate phytophagous insects require rapid and more accurate means of assessing foliage consumption. Methods based on measurements of leaf areas instead of the direct weight of food consumed have been adopted in several laboratories. The literature on photometric techniques for measuring leaf areas and a method for use in the analysis of preference tests with leaf discs have been reviewed and described (Kogan and Goeden 1969). Hennessey and Maddox (1971) used this photometric method in routine biological weed-control experiments, and they commented on the accuracy of its calibration. Pedigo et al. (1970) used photometric measurements of transmitted light in studies of leaf consumption by the green cloverworm, Plathypena scabra (F.). Jones and Thurston (1970) used Xerox® copies of leaves to measure the consumed area with a planimeter, and Pond et al. (1970) used contact prints to assess damage by the potato flea beetle, Epitrix cucumeris (Harris).

Feeding and Nutrition of Insects Associated with Soybeans: 1. Growth and Development of the Mexican Bean Beetle, Epilachna varivestis,1 on Artificial Media

A semiliquid medium applied to layers of Cellucotton®, was readily accepted by 3rd- and 4th-stage larvae of the Mexican bean beetle, Epilachna varivestis Mulsant (Coleoptera: Coccinellidae). Larvae reared on this medium completed development and yielded normal adults. Tests were conducted with a total of 19 semiliquid (sol) and agar-base (gel) media differing in sucrose concentration, source of essential amino acids, and p H. A solcasein medium with 0.1M sucrose yielded the best results. This medium was used in routine rearings of the beetle, partially replacing fresh bean leaves. The solcasein medium was found extremely convenient in studies on host selection and nutrition of the Mexican bean beetle in its associations with soybeans.

V. The uptake of free and serum-bound sterols by insect cells in vitro.

The importance of sterols in insect nutrition has been accepted for some time, and all synthetic diets for insects contain one or more sources of these compounds (Smith, 1966). The sterols are necessary because, unlike other animals, insects are incapable of synthesizing them from simpler, precursor compounds (Clark and Block, 1959). It therefore seems likely that insect cells grown in culture also cannot synthesize these vital materials. Stanley and Vaughn (1967) considered a marked sensitivity of insect cells to the anti-fungal agent amphotericin B circumstantial evidence that the cells were dependent on exogenous cholesterol because amphotericin B apparently binds the sterols of the cell membrane and thus alters the physical structure of the membrane (Lampen et al., 1965). If the cells had been capable of synthesizing cholesterol the removal of exogenous sterol could have been overcome.

Physiological influences on wood-destroying insects of wood compounds and substances produced by microorganisms

Wood-destroying insects react to and depend regarding their nutrition on compounds contained in wood or produced by microorganisms in wood. This relation is a complex matter in the biology of the insects and the chemistry of wood and of the metabolism of woodinhabiting microorganisms. Results on the reaction of Coleoptera and Isoptera to attractive or repellent compounds in wood species or substances produced by fungi in wood are reviewed with emphasis to differences among various insect species. Nutrition of wood-destroying insects depends on nitrogen compounds of the wood; the content of nitrogen can be increased by the presence of fungi. Existing results on the relation between microorganisms and insects are also summarized including toxicity or parasitic influence of part of the microorganisms on insects. The survey may stimulate further investigations which are necessary for better knowledge of the complex interrelations.

Influence of the Quality of Protein in Pollens and of a Pollen Substitute on the Development of the Hypopharyngeal Glands of Honey Bees1,2,3

Numerous scientific investigators have shown that the protein in different kinds of pollens varies widely in quality, quantity, and food value for honey bees, Apis mellifera L. (Todd and Bretherick 1942; Lunden 1956; Standifer 1966, 1967). However, apiculturists and other entomologists engaged in studies of insect nutrition frequently disregard these findings and incorporate pollens of unknown source and chemical composition (see references cited in Standifer et al. 1960, Standifer 1967) into experimental diets. The present investigation was made at the Honey Bee Pollination Investigations Laboratory at Tucson, Ariz., to determine the effect of equal amounts of 2 chemically different pollens and of a pollen substitute diet on the growth of nurse honey bees as indicated by the morphological development of the hypopharyngeal glands.

Utilization of sterols by larvae of Drosophila melanogaster

Twenty sterols were tested for their ability to replace cholesterol in an axenic, defined diet for Drosophila melanogaster. Larval development rate, survival to eclosion, and weight were used as criteria of efficiency. Only sterols with an intact, planar ring structure, with a side-chain similar to that of cholesterol and with a 3β-OH grouping support full development. Phytosterols are superior to cholesterol; and Drosophila shows a pattern of sterol utilization similar to other phytophagous insects. Departures from this are discussed, including the ability of dihydrocholesterol to substitute for cholesterol. The limited ability of larvae to use desmosterol, althought they grow normally when this is supplemented with small amounts of cholesterol, is taken to confirm the view that sterols have a bulk and a micronutrient rôle in insect nutrition. Interstrain comparisons show that genotypic differences may influence ability to utilize various sterols.

Sterile Culture of Musca sorbens1,2

There has been increased use of gnotobiotic insects, especially in areas of insect pathology, nutrition, and tissue culture. The need for germ-free explants from larvae, pupae, and adults of the fly Musca sorbens Wiedemann for tissue culture studies prompted the culture method described here. It is the 1st report of the sterile culture of this fly known to me.