Dale M. Norris

Pupation requirement of the beetle, Xyleborus ferrugineus: sterols other than cholesterol.

Abstract Aposymbiotic Xyleborus ferrugineus utilized cholesterol or lanosterol as a sole source of sterol for production of eggs and hatching of larvae, but failed to pupate during consecutive broods or generations in diets with such sources of sterol. The insects produced several broods or generations of progeny that pupated and formed normal adults when ergosterol or 7-dehydrocholesterol was the sole source of sterol. Lumisterol, or vitamin D 2 or D 3 , was antagonistic to progeny production or survival.

Ultrastructure of sensory receptors on the antennae of Scolytus multistriatus (Marsh.).

SummaryThe antennae of Scolytus multistriatus were examined with light and scanning and transmitting-electron microscopy to determine the distributions, types and structures of sense organs. Four types of sensilla were found: (1) sensilla chaetica, a singly-innervated receptor; (2) sensilla basiconica, Type A, a short, thin-walled, multiple-innervated receptor; (3) sensilla basiconica, Type B, a long, thin-walled multiple-innervated receptor; and (4) sensilla trichodea, short, thick-walled, multiple-innervated receptors. The positioning of dendrite(s) with regard to pore tubules is elaborated. Evidence for lack of sensory axon fusion is presented.

A complex of fungi mutualistically involved in the nutrition of the ambrosia beetle Xyleborus ferrugineus

Abstract Paired oral mycangia (organs in which mutualistic fungi are perpetuated) were present in both sexes of the ambrosia beetle Xyleborus ferrugineus . The mycangia of stock culture beetles bore a complex of fungi, yeast, and bacteria. Fusarium solani was the dominant fungal symbiote, but a Cephalosporium sp., and a Graphium sp. also were isolated from 50% and 20% of the beetles, respectively. All three fungi formed “ambrosia” growth on the walls of brood tunnels when inoculated singly into tubes of medium bearing one female beetle previously freed of fungi. The fungus that was inoculated into a given tube of medium was the only fungus subsequently recovered from mycangia of adult beetles in that tube. Each fungus grew in characteristic forms in the mycangia of the beetles. Each of the three fungi provided the nutrients or concentrations of nutrients, not contained in the medium, that were essential to reproduction by the insect.

Juglone (5-hydroxy-1,4-naphthoquinone) from Carya ovata, a deterrent to feeding by Scolytus multistriatus

Abstract Juglone (5-hydroxy-1,4-naphthoquinone) from the bark of Carya ovata proved to be a deterrent to feeding by Scolytus multistriatus. When juglone was removed from the extracts of the hickory bark, S. multistriatus fed extensively on the remaining extracts. The beetle fed, to varying extents, on bark extracts from several other species of trees.

Symbiosis: Effects of a Mutualistic Fungus upon the Growth and Reproduction of Xyleborus ferrugineus

Xyleborus ferrugineus beetles developed from asymbiontic eggs through the adult stage on a sterilized meridic diet, but the resulting adults reproduced only when a mutualistic fungus was inoculated into the diet. Beetles with bacterial symbionts still required the fungus for reproduction on a second meridic diet.

Energy transduction in quinone inhibition of insect feeding

Abstract Variously substituted 1,4-naphthoquinones inhibited (deterred) feeding by Periplaneta americana. Certain sensilla on the antennae were important receptors for the deterrent stimulus. Dendritic branches of sensory neurons in the sensilla are exposed to the exogenous inhibitory chemicals via pores which penetrate the cuticle. The order of relative degree of complexing of a given naphthoquinone to density-gradient fractions of antennal homogenates rich in nerve membrane fragments matched the order of relative deterrency of that chemical to feeding. Sulphhydryl groups of protein in the antennae were important sites of reaction. Energy transduction at the receptor site involved complexing of the quinone with the receptor chemical and the ultimate reduction of the quinone to its quinol. Energy transfer between sulphhydryl groups and quinones provided a mechanism which could bring about a change in conformation of the receptor macromolecule which could allow inorganic ion flows to generate the action potential of the neuron.

A chemical basis for bark beetle (Scolytus) distinction between host and non-host trees☆

Abstract The bark beetle, Scolytus quadrispinosus, tolerated 5-hydroxy-1,4-nappthoquinone from a host tree, Carya ovata, that was a deterrent to feeding by Scolytus multistriatus. S. multistriatus fed as extensively on the benzene extract of C. ovata twig bark when 5-hydroxy-1,4-naphthoquinone was removed as it did on the benzene extract of its host, Ulmus americana. S. multistriatus feeding on the benzene extract of U. americana also was deterred by the addition of an extract of Quercus alba twig bark. These findings indicate that deterrency by chemicals in the bark of non-host trees is an important basis for bark beetle distinction between non-host and host tissues.

Volatiles mediating plant-herbivore-natural enemy interactions: Electroantennogram responses of soybean looper,Pseudoplusia includens, and a parasitoid,Microplitis demolitor, to green leaf volatiles.

Electroantennograms were recorded from an herbivore,Pseudoplusia includens (Walker) (Lepidoptera: Noctuidae), and a parasitoid,Microplitis demolitor (Wilkinson) (Hymenoptera: Braconidae), exposed to 5-through 12-carbon aliphatic compounds of several chemical classes. The response of the herbivore was higher for the 6- and/or 7-carbon hydrocarbons, alcohols, aldehydes, esters, and ketones. The response of the parasitoid was higher for the 7- and 8-carbon hydrocarbons, aldehydes, and ketones. Responses of the herbivore and the parasitoid to alcohols were similar. Both the herbivore and the parasitoid were most sensitive to aldehydes and ketones, and least sensitive to alcohols and hydrocarbons. Responses of the parasitoid to hydrocarbons, aldehydes, and ketones were numerically higher than those of the herbivore. The adaptive significance of differential olfactory sensitivity between the herbivore and the natural enemy is discussed in relation to tri-trophic interactions among plants, herbivores, and natural enemies.

Feeding responses of the beetle Scolytus to chemical stimuli in the bark of Ulmus

Abstract Feeding responses of Scolytus multistriatus adults on assay disks soaked in 5 mg of a benzene extract of second- to fourth-year twig bark of Ulmus americana collected on 6 June 1966 were significant (0·01 level) from the control. The same assay of a benzene extract of current-year twig bark collected 6 June, 1966 yielded a non-significant (0·05 level) feeding response. Alkaline hydrolysis of the benzene extract destroyed the significant (0·05 level) feeding-stimulant activity. Excellent separation of the chemicals in the benzene extract was obtained with thin-layer chromatographic techniques. Feeding responses to an 80% ethanol extract of benzene extracted bark were not significantly different (0·05 level) from those of controls. Several sugars present in elm tissue failed to stimulate feeding.

Symbiotic interrelationships between microbes and ambrosia beetles: VII. Bacterial symbionts associated with Xyleborus ferrugineus

Abstract Transovarially transmitted bacterial symbionts, classified in the genus Staphylococcus , were isolated and pure cultured from the gut lumen of all stages of the ambrosia beetle, Xyleborus ferrugineus . These bacterial symbionts were shown to invade the oocytes, and this invasion was associated with the initiation of nuclear division while the oocytes were surrounded by the follicular wall in the ovariole and unfertilized by sperm.