Defensive alkaloid in blood of Mexican bean beetle (Epilachna varivestis)

The blood of the Mexican bean beetle (Epilachna varivestis) contains a homotropane alkaloid, euphococcinine (1). The beetles 'reflex bleed' when disturbed, thereby deploying the alkaloid, which is provenly deterrent to spiders and ants. Newly emerged adults lack the alkaloid, but the compound builds up to deterrent levels in their blood within days. Eggs and larvae of Epilachna are devoid of the compound.     

Defensive steroids from a carrion beetle (Silpha americana)

Summary The defensive anal effluent discharged bySilpha americana in response to disturbance contains a mixture of steroids stemming from a glandular annex of the rectum. The compounds have been characterized as 15-hydroxyprogesterone (1, principal component), 5-pregnan-15-ol-3, 20-dione (2), 5-pregnan-3, 15-diol-20-one (3), 5-pregnan-7, 15-diol-3,20-dione (4), 5-pregnan-3, 7, 15-triol-20-one (5), 5-pregnan-16-ol-3,20-dione (6), and 5-pregnan-3, 16-diol-20-one (7), none previously found in insects. Bioassays with jumping spiders showed compounds1 and6 to be feeding deterrents at the 1 g level.Paper No. 78 of the series: Defense Mechanisms of Arthropods. Study supported by NIH (Grants AI-02908, AI-12020). We thank Maura Malarcher and Maria Eisner for excellent technical help, and the Squibb Institute of Medical Research for samples of authentic reference compounds.     

Paternal allocation of sequestered plant pyrrolizidine alkaloid to eggs in the danaine butterfly,Danaus gilippus

Summary Pyrrolizidine alkaloid sequestered by adult maleDanaus gilippus from plants is transferred in large measure to the female at mating, and by the female to the eggs. The eggs, presumably, are protected as a result. The male's courtship pheromone, danaidone, derived from the sequestered alkaloid, may function to advertise the male's alkaloid-donating capacity.Acknowledgments. Paper Nr. 89 of the series Defense Mechanisms of Arthropods. Study supported by NIH (Grants AI-02908 and AI-12020; Predoctoral Traineeship to DED), Hatch funds (191-7416), the Bache Fund (National Academy of Sciences, to DED), and the Theodore Roosevelt Memorial Fund (American Museum of Natural History, to DED). We thank M. Weingarner and J. Miller forD. gilippus collection, J. Boggan for technical assistance, and the staff of the Archbold Biological Station, Lake Placid, Florida, for assistance and hospitality. One of us (DED) is indebted to M. D. Achey, who by demonstrating nuptial cardenolide transfer in the monarch butterfly [Honors Thesis, Amherst College, Amherst, Massachusetts (1979)] raised the possibility that other plant metabolites might be similarly transferred in danaines.Deceased July, 1985. This paper is affectionately dedicated to his memory.     

Tocopheryl acetates from the pupal exocrine secretion of the squash beetle,Epilachna borealis (Coccinellidae)

The oily droplets on the pupal integumental hairs of the squash beetleEpilachna borealis contain a mixture of -, -, -, and -tocopheryl acetates as major constituents. In addition, the secretion contains a number of minor components that appear to be dehydrocongeners of the major components. This is the first report of the occurrence of acetate esters of any tocopherol in nature.This is paper No. 132 in the series Defense Mechanisms of Arthropods; No. 131 is Shi et al., Tetrahedron52 (1996) 6859.     

Sexual dimorphism in the lipid fraction of the defensive secretion ofGastrophysa viridula (Coleoptera: Chrysomelidae)

The lipid fraction of the defensive secretion of adultGastrophysa viridula was analyzed by gas-liquid chromatography and gas chromatography-mass spectrometry. Three long chain acetates and two methyl-branched hydrocarbons were identified and their amounts in the secretion of single field-collected and laboratory-reared beetles determined. The composition of the secretion was affected by the sex, reproductive status, and age of the beetle. The ratio of (Z)-11-eicosenyl acetate to (Z)-13-docosenyl acetate ranged from 0.30 to 0.78 in male beetles and from 1.05 to 2.06 in female beetles. The biological significance of this sexual dimorphism is discussed.     

The origin of progesterone in the confused flour beetle (Tribolium confusum)

Résumé La progestérone présente dans les tissus deTribolium confusum (coléoptère) tire probablement son origine de la ration alimentaire puisque la concentration de ce stéroïde est du même ordre de grandeur dans l'insecte et dans la ration alimentaire.     

Response ofPhloeotribus scarabaeoides (Coleoptera,Scolytidae) to ethylene in an olfactometer

The role of ethylene, pure or in formulation, in the colonization behaviour of the olive bark beetle,Phloeotribus scarabaeoides (Coleoptera, Scolytidae) has been investigated in the laboratory. Ethylene has been found to be attractive in both sexes; the formulation ethrel 48 was active in an olfactometer up to several months. Ethylene, whose concentration varies with the developmental stage or the condition of the tree or its wood, may play an important role in the primary attraction of these scolytids to their host.     

Use of oven-dried blood for in vitro feeding of tsetse flies

Summary Comparison of the survival, fecundity and offspring size ofGlossina palpalis palpalis females fed reconstituted over-dried blood, fresh, frozen/thawed, or reconstituted freeze-dried blood showed that oven-drying at 45°C does not diminish the nutritional quality of blood. The significance of this finding is discussed with a view to optimizing costs and conditions of blood-diet storage and transportation in the context of mass-rearing of tsetse flies.     

Chemical basis of pupal cannibalism in a caterpillar (Utetheisa ornatrix)

The mothUtetheisa ornatrix derives protection against predation from systemic pyrrolizidine alkaloids (PAs) that it sequesters as a larva from its foodplants (Leguminosae,Crotalaria spp.). We here show, in laboratory tests, thatUtetheisa deficient in body PA can make up for the chemical shortfall by cannibalizing pupae. We present evidence indicating that cannibalism in larvae is elicited not by hunger, but possibly by PA deficiency itself, and that in making cannibalistic choices larvae prefer PA-containing over PA-free pupae. PAs themselves, either in crystalline form or as additives to food items, proved phagostimulatory to larvae. In natureUtetheisa tend to pupate away from their foodplant, essentially out of reach of larval attack. The threat of cannibalism may have contributed to the evolution of this pupation behavior.Paper No. 102 of the series Defense Mechanisms of Arthropods; No. 101 is Eisner et al., Chemoecology (in press).     

Mitochondrial DNA variation in geographic populations of Colorado potato beetle,Leptinotarsa decemlineata (Coleoptera; Chrysomelidae)

Summary This study demonstrates variability in restriction enzyme cleavage sites of mitochondrial DNA (mtDNA) among four popalations of Colorado potato beetle (CPB). A suite of three enzymes (EcoRI,HpaI,PstI) was sufficient to discriminate among the populations tested. Individuals heteroplasmic for restriction enzyme patterns were found in some populations. Variability in CPB mtDNA should prove useful in efforts to trace the origin and dispersal of the species in North America.     

Nα-quinaldyl-L-arginine·HCl,a new defensive alkaloid fromSubcoccinella-24-punctata (Coleoptera,Coccinellidae)

The isolation of N-quinaldyl-L-arginine·HCl (1) from the CoccinellidaeSubcoccinella-24-punctata is reported. The structure, first established on the basis of the analysis of the spectral properties of1, has been confirmed by synthesis. The alkaloid is of endogenous origin and markedly deterrent to ants.     

Reduction in bean common mosaic virus (BCMV) infectivity vis-a-vis crude leaf extract of some higher plants

Summary Crude leaf extracts of 17 plants were tested for their antiviral activity against BCMV. An extract ofAzadirachta indica A. Juss. was found to be most potent in reducing the infectivity of the virus.Authors are thankful to Dr R. D. Joshi for his valuable guidance and Prof. S. N. Mathur for providing lab facilities. Financial assistance by U. G. C. and C. S. I. R. is gratefully acknowledged.     

The influence of ethylene on primary attraction of the olive beetle,Phloeotribus scarabaeoides (Bern.) (Col., Scolytidae)

Two experiments have been carried out to verify the effect of ethylene on the primary attraction ofPhloeotribus scarabaeoides under both laboratory and field conditions. The experiments were based on the enhancement of ethylene production by olive branches and trunks after the application of (2-chloroethyl)phosphonic acid. Under laboratory conditions, the beetles' response was strongly stimulated on the treated branches. Under field conditions, the treatment aided the location of the olive wood by the flying beetles, and the attack density was significantly greater in the treated wood at the end of the experiment.     

On the specific attraction of the males of the six-toothed spruce bark beetle,Pityogenes chalcographus (L.) to a mixture of synthetic pheromones of the eight-toothed spruce bark beetle,Ips typographus (L.) (Coleoptera,Scolytidae)

Summary Traps containing a mixture of attractants forIps typographus also caught other species of bark beetles. The numbers ofPityogenes chalcographus, Pityogenes conjunctus, andTrypodendron lineatum were too high to be interpreted as accidental captures. The males of the polygamousP. chalcographus were specifically attracted, indicating that theI. typographus pheromone or one of its components acts as a kairomone and primary attractant for the pioneering males ofP. chalcographus.     

Chemical defence in the larvae of the leaf beetleGonioctena viminalis L. (Coleoptera: Chrysomelidae)

Summary The leaf beetle larva ofGonioctena (Phytodecta) viminalis L. has been shown to produce five volatile constituents within its paired abdominal defensive gland reservoirs. It is the first time that these compounds have been reported to occur in coleopteran defensive glands (linalool, phenylethanol) and Chrysomelidae larvae (6-methyl-5-hepten-2-one, 6-methyl-5-hepten-2-ol, 2-hexenal). In addition to the gross morphology of theGonioctena gland and its discharge behavior, the natural products found are discussed in terms of chemotaxonomy.     

Cell wall polymers in Archaea (Archaebacteria)

The distribution of the various cell wall and cell envelope (S-layer) polymers among the main lineages of the domain Archaea (Archaebacteria) and the chemical composition and primary structure of polymers forming rigid cell wall sacculi is described. Differences between bacteria and archaea in their sensitivity to antibiotics which inhibit cell wall synthesis in bacteria are discussed.     

Extravasation of blood cells in and around the pituitary ofAnabas scandens (Cuvier)

Zusammenfassung Es wurden Gruppen von Blutzellen innerhalb und in der Umgebung der Hypophyse vonAnabas scandens und besonders in der Mesoadenohypophyse gefunden. Dies fällt auf, da die Mesoadenohypophyse im allgemeinen nicht reich mit Gefässen versorgt ist. Die Gefässversorgung dieser Stelle zeigt, dass das Sekret direkt von der Mesoadenohypophyse ins Blut übergeht, während die Anhäufung von Blutzellen in der Hypophyse pathologische sein dürfte.     

The effect of leafhopper infestation on the respiration of castor bean varieties in relation to their resistance toEmpoasca flavescens (F.) (Homoptera: Jassidae)

Zusammenfassung Die Saugtätigkeit der JassideEmpoasca flavescens (F.) führte zu einer um 44% gesteigerten Respiration von geschädigten, anfälligen Rizinuspflanzen (Ricinus communis L.) im Vergleich zu 11.6% und 3.7% bei Pflanzen einer toleranten und resistenten Sorte. Diese Zunahme war bei der anfälligen Sorte verknüpft mit einer gesteigerten Anhäufung von Rohrzucker, Gesamtstickstoff und Gesamtaminosäuregehalt.

---

---

This study formed part of the Doctoral Thesis submitted to the University of Madras and financial support was given by the Council of Scientific and Industrial Research, Government of India, New Delhi. Grateful appreciation is extended to Prof. A. R.Seshadri, Agricultural College and Research Institute, Coimbatore, India and Prof. R. H.Painter, Kansas State University, Kansas, U.S.A. for their valuable suggestions made during the course of the study.