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Secretory-type epithelial cells of the adult female western corn rootworm, Diabrotica virgifera LeConte (Chrysomelidae), apparently responsible for releasing the sex pheromone, are composed of 2 groups of cells. One group is columnar, arranged in a “U” shape, and located dorsally between tergites 7 and 8; the cells of the 2nd group are cuboidal and located ventrally between sternites 7 and 8. Individual cuticular pore openings occur on the 7th abdominal segment and correlate spatially with the epithelial secretory cells.

Adult Tenebrio molitor L. were exposed to 39-MHz radiofrequency (RF) electric fields and examined to determine cytopathological changes in ovarian and testicular tissues. Disintegration of trophocytes and primary oocytes followed by vacuole formation in the germarium and germinal vesicle characterized the effects in ovarian tissue. Condensation of the chromatin material in the follicular epithelial cells was also evident. In testicular tissues, RF treatment caused disintegration of the cyst membranes and spermatocytes and clumping of spermatid nuclei. Mature spermatozoa were not observed in the lumina of the vasa efferentia.

Scanning electron micrographs and serial longitudinal and cross sections of the western corn rootworm, Diabrotica virgifera LeConte , antennae revealed that the antennal structure of males and females was similar. However, the longer ♂ antennae have more sensilla and possess 6 types of sensilla on the terminal antennal segment not found on the terminal segment of ♀ antennae; the ultimate antennal segment of the female possesses 4 sensillar types not found on the comparable antennal segment of the male.

One- and 3-day-old Tenebrio molitor L. eggs were exposed in special polystyrene holders to radiofrequency (RF) electric fields of different intensities for periods ranging from 2 to 64 seconds. The percent eggs hatched, percent survival of larvae to 10 days, and embryological development were observed following exposure to these RF electric fields. Percent hatch of 1- and 3-day-old T. molitor eggs exposed to RF energy was in general inversely related to the RF energy level. One-day-old eggs were more susceptible than 3-day-old eggs. When the larval stage was attained, interference with normal developmental processes was not apparent. Histological preparations of embryos exposed to RF fields showed that injury to the blastoderm and the germ band depended upon the age of the egg at the time of treatment and indicated that RF treatment adversely affected further embryological development.

Adults developing from larvae of the yellow mealworm, Tenebrio molitor L., exposed at sublethal levels to radio-frequency electric fields, exhibited malformed and missing legs. The number of imaginal legs was reduced as exposure time increased. The degree of leg malformation increased when treatment was administered later during the last (sixth) instar. Similar treatments of fifth-instar larvae did not interfere with normal imaginal leg development. Deformities most likely result from heat damage to the histoblasts which project into the legs of the last-instar larvae.

Data obtained from olfactometer tests demonstrated the presence of a sex pheromone in the hexane extract of 5-day-old virgin female face flies, Musca antumnalis De Geer (Diptera: Muscidae). Results of chromatography and simple chemical procedures suggest that the pheromone is an unsaturated hydrocarbon. The sex pheromone of the female face fly probably influences the behavior of the male in 2 ways, by attracting him to the pheromone source and by sexually stimulating him to initiate copulation. Apparently, both visual and olfactory stimuli are involved in the orientation mechanism of the male to the female face fly. The pheromone is perhaps operative over a relatively great distance whereas vision is probably used by pheromonestimulated males for only short-range orientation.

Locomotor activity rhythms of Periplaneta americana (L.) were found to be entrained through the compound eyes and not the ocelli. When the entire head capsule was occluded, the locomotor activity rhythm was random. For those insects having the terminal abdominal sclerites occluded, there was more activity during the photophase than during the scotophase; locomotor activity at the light-to-dark transition was comparable to that of control insects. Transection of the ventral nerve cord did not appear to alter locomotor activity. The involvement of the terminal abdominal ganglion in locomotor activities is considered. Two new low-friction switching methods to record locomotor activity are described.

Various portions of the antennae, mouth parts, and legs were painted with shellac to inactivate possible hygroreceptive areas thereon, and the times required by the insects to locate water following these various treatments were recorded. Through a process of elimination the distal part of the fourth antennal segment was found chiefly responsible for hygroreception. Supporting evidence for this was obtained through use of an olfactometer. Sections through the antennae showed considerably more nervous tissue in the fourth segment than in the others.

The relative transmittance of visible and infrared radiation was measured for cuticle from the vertex, 2 pairs of wing tips in repose plus underlying tergite, light and dark pigmented pronotal areas, one wing tip, and the 6th abdominal tergite and sternite of the cockroach, Blaberus craniifer Burmeister. Significant differences in transmission between these cuticular areas, measured in μw/cm2, were observed with the light pigmented pronotal cuticle having the highest and the dark pigmented pronotal cuticle having the lowest percent transmittance at all wave lengths.

When larvae and adults of Tenebrio molitor L. were exposed at sublethal levels to 39-MHz radiofrequency (RF) electric fields, the RF treatment of last-stage larvae and adults reduced female fecundity. The reduction fecundity was more pronounced with longer periods of exposure and higher electrode voltages. The effect of RF energy on fecundity was more dependent upon treatment of males than upon treatment of females. Exposure of larval stages to RF energy resulted in a reduction in both the size of the ovaries and the number of eggs which developed in females that emerged from treated larvae.

The sequence of mating behavior for virgin western corn rootworms, Diabrotica virgifera LeConte, included the following behavioral categories: preliminary courtship and mounting; physical stimulation of the female by the male; and copulation. Various tactile stimuli, including antennal palpitation and stroking activities involving the mesothoracic legs, were performed by the male during the mating process.

Adult O. fasciatus (Dall.) were exposed in boxes offering a two-choice situation between various wave lengths in the visible spectrum. Opaque and clear exposures were similarly tested. In any given color combination, more insects chose the shorter wave length. These results are interesting because in general the longer wave lengths are more deleterious in nature than the shorter wave lengths. The location of photoreceptors other than ocelli and compound eyes is speculated upon.