Catnip: Its Raison d'Etre

Catnip (nepetalactone) is closely related chemically to certain cyclopentanoid monoterpenes recently isolated from insects, and it shares with some of these terpenes an ability to repel insects. It is suggested that the adaptive function of catnip is to protect the plants that produce it against phytophagous insects.

EFFECT OF DDT AND STARVATION ON THE ANTIGENIC COMPOSITION OF SITOPHILUS GRANARIUS (L.) (COLEOPTERA), GG STRAIN, AND A COMPARISON WITH OTHER STRAINS AND SPECIES, USING THE OUCHTERLONY TECHNIQUE

By use of the Ouchterlony technique it has been possible to distinguish immunologically certain strains and species of Sitophilus, and, in S. granarius, to distinguish among normal, starved, and DDT-poisoned weevils. The immunological differences distinguishing strains and species were greater than those distinguishing different treatments in the same strain. The results also indicated that the metabolism of insects dying of DDT toxemia may not be as similar to that of starving insects as has been suggested in the literature.

Venom and Venom Apparatus of the Bull Ant, Myrmecia gulosa (Fabr.)

The venom of Myrmecia gulosa (Myrmeciinae, Formicidae) is of a proteinaceous type and is separated by electrophoresis into eight components. The venom contains histamine, a hyaluronidase, and a direct hemolytic factor. It also shows kinin-like activity. In structure the venom apparatus is found to be massively formed internally as well as externally. It is distinguished from the apparatus of representatives of other ant subfamilies by characteristics of the free gland filaments, the reservoir wall, the intra-reservoir glandular area, and the accessory gland.

NEUROSECRETORY CELLS IN A NEMATODE, ASCARIS LUMBRICOIDES

This paper describes nerve cells in the anterior end of Ascaris, which, because they contain granules which stain with paraldehyde-fuchsin, are held to be neurosecretory. There are 20 such cells in all: 10 are labial sense cells, 2 are associated with the amphidial glands, 2 are associated with one of the subsidiary ganglia anterior to the nerve ring, and 6 are contained in the lateral ganglia. Changes which occur in these cells after removal of the worm from the host are described.

Insect Tissue Culture: Use of Blastokinetic Stage of Leafhopper Embryo

To find the proper material for cultivation in vitro of cells of leafhopper vectors of plant viruses, embryonic tissues of the six-spotted aster leaf-hopper (Macrosteles fascifrons) were tested during early developmental stages, during blastokinetic movement, and in late developmental stages. Growing cells were only obtained from the stage of blastokinetic movement. This stage can be determined visually in leafhopper eggs.

EMBRYOGENESIS OF MESOLEIUS TENTHREDINIS MORL. (HYMENOPTERA: ICHNEUMONIDAE)

The embryogenesis of the parasitic ichneumonid Mesoleius tenthredinis Morl. is more similar to that of the ichneumonid Pimpla turionellae (L.) than to that of the other monembryonic ichneumonids (Banchus femoralis (Thoms.) and Diadegma vestigialis (Ratz.)) that have been studied in detail. The differences between the embryogeny of M. tenthredinis and that of P. turionellae are reduction of periplasm; proliferation of the middle plate cells after their overgrowth by the lateral plates; extension of the tail end of the germ anlage to produce a dorsal, anal opening; intercellular pole cell reentry just before the occurrence of gastrulation caudally; no rudimentary amnion; and incorporation of many deutoplasmic granules in the serosal cells, so that the embryo is completely surrounded by a layer of deutoplasm following embryonic envelope formation. The mode of embryonal development indicates that P. turionellae and M. tenthredinis are primitive endoparasitoids.

trans -2-Dodecenal and 2-Methyl-1,4-Quinone Produced by a Millipede

An aldehyde, trans-2-dodecenal, heretofore known only from plants, has been identified in the defensive secretion of the spiroboloid millipede Rhinocricus insulatus. A second component, 2-methyl-1,4-quinone, was previously known from the secretion of related millipedes.

THE EFFECT OF PHOTOPERIOD AND TEMPERATURE ON THE PRODUCTION OF GAMIC AND AGAMIC FORMS IN MACROSIPHUM EUPHORBIAE (THOMAS)

Apterous and alate Macrosiphum euphorbiae (Thomas) from a clone reproducing agamically since 1952 produced viviparae and sexuales when exposed to certain photoperiods and temperatures. The kinds of offspring produced were influenced by day length, parent type, "generation", and temperature. The greatest percentage alate viviparous females was produced when the day length was between 11 and 13 hours and when the first "generation" parents were apterous. The greatest percentage of apterous viviparous females was produced when the day length was greater than 13 hours and when the parents were First "generation" alatae. The greatest percentage of oviparous females was produced by second "generation" alatae and that of males by fourth "generation'' apterae. It is suggested that temperature does not influence directly the kind of offspring produced, hut does so indirectly by its effect on the number of light/dark cycles of an effective photoperiod that occur during the critical stage in the life of the aphid.

Daily Fluctuation in the Blood Sugar Concentration of the House Cricket, Gryllus domesticus L

The disaccharide trehalose is the main carbohydrate constituent in the hemolymph of the house cricket, Gryllus domesticus L. At different times of day the blood sugar in the hemolymph of crickets showed a fluctuation in trehalose concentration, which reached a peak value about 3 hours before dawn.

Mimicry: Differential Advantage of Color Patterns in the Natural Environment

With a new modification of the release and recapture technique in which day-flying male moths are artificially painted, released, and then lured by their females into traps, it has been possible to obtain differential recapture frequencies in natural areas of the Neotropics.