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Fourteen lepidopterous synthetic sex pheromones were evaluated over 2 seasons (1982 and 1983) for their efficacy in trapping temperate fruit pests. Four insect pests, Archips pomivora Meyrick, A.sp.nr. hemixantha Meyrick, Acleris orphnocycla Meyrick (Tortricidae) and Lymantria concolor Walker (Lymantriidae) responded to the pheromones in varying degrees. OBLR, FTLR and LAW pheromones attracted the largest proportion (41.4, 20.2 and 16.3%, respectively) of A. pomivora , the predominate tortricid infesting apple in Himachal Pradesh. GM pheromone attracted L. concolor , a defoliator of temperate fruits. CM, GFUN and OFM pheromones did not trap Cydia pomonella (L.), Grapholitha funebrana (Treitschke) or G. Molesta (Busck) and therefore complete absence of these pests in Himachal Pradesh is suggested.

Ooencyrtus kuvanae (Howard) parasitism of gypsy moth, Lymantria dispar (L.), egg masses (EMs) laid on different host species and substrates was studied in newly infested areas in Virginia. Parasitization rates of gypsy moth EMs by O. kuvanae were highest on red maple and inanimate objects and lowest on oaks. The effect of host plant species on parasitism was independent of the number of eggs per mass and may be due to the effects of bark texture on egg mass geometry and searching behavior of O. kuvanae . Percent parasitization was also inversely related to eggs per mass; the latter is a function of host suitability and gypsy moth population density. O. kuvanae appears to be incapable of maintaining gypsy moth populations at low densities but may be an additional factor mediating against the reproductive success of individuals feeding on nonpreferred host plant species.

Chitinase significantly enhanced the activity of nuclear polyhedrosis virus (NPV) ingested by second-instar gypsy moth, Lymantria dispar (L.). Multiple probit regressions calculated from mortality observed at 14 and 21 d indicated that the LC50’s of NPV declined 1.3-, 2.0-, 3.2-, and 5.4-fold with the addition of 0.001, 0.010, 0.10, and 1.00% chitinase, respectively. In addition, insects exposed to NPV-chitinase combinations died more rapidly than those that ingested NPV only.

Two odour receptor cells were physiologically identified within male antennal hair sensillae of the gypsy moth, Lymantria dispar L, and the nun moth, L. monacha L. In the gypsy moth, one cell responded to (+)-disparlure, while a neighbouring cell responded to (-)-disparlure. In the nun moth both cells responded to (+)-disparlure. The lack of sensitivity to (-)-disparlure in the nun moth was corroborated by electroantennogram (EAG) recordings, which indicated no affinity to this enantiomer. Single cell responses of male gypsy moth to different concentrations of the synthetic enantiomers of disparlure were then compared to responses elicited by hexane extracts of female glands of both species. The gypsy moth's extracts stimulated almost exclusively the receptor cell specialized for (+)-disparlure, while both cells were simultaneously stimulated by the extracts of the nun moths. From the response characteristic of the cells it is estimated that pheromone production of the nun moth is about 10% (+) and 90% (-)-disparlure, and that of the gypsy moth is almost 100% (+)-disparlure. Stimulation of the antenna of each species by female gland extracts of both species did not indicate the presence of receptors for other hexane elutable pheromone components in either species.

Eastern tent caterpillars (Malacosoma americanum) are behavioral thermoregulators while gypsy moth caterpillars (Lymantria dispar) are thermal conformers. Differences in thermal ecology can be related to differences in the environments these species encounter. Temperature sensitivity of growth rates differs in a predictable manner; the growth rates of gypsy moth caterpillars are temperature independent at ecologically relevant temperatures of 25°—30°C, and the growth of the tent caterpillars is very temperature dependent. Growth rates of tent caterpillars in the field are greater than that expected for the average ambient temperature of 15°, and closely approximate growth in the laboratory at 25°, near the average Tb exhibited in the field. The higher growth rates are a result of the tent caterpillars' elevated body temperatures. These data are used to develop hypotheses for the evolution of caterpillar thermal responses. See full-text article at JSTOR

The attractive power of disparlure-the sex attractant of the gypsy moth (Lymantria/Porthetria dispar)-vs. four synthetic analogous epoxides was tested in 1972 in a pine forest near Heidelberg. With two levels of concentration in the traps (2 and 20 μg), a total of 1112 nun moths (Lymantria/Porthetria monacha) and 257 gypsy moths were caught in 9 experiments. Approximately equal percentages of the two species were caught with a given compound. Disparlure was by far the most effective attractant. The other substances were between three and twenty times less effective. These experiments support the assumption that disparlure is also at least part of the sexual attractant of the nun moth. In two additional experiments, moth captures by a series of increasing disparlure concentrations (2-100 μg/trap) were determined. The catches of both species increased nonlinearly with the bait concentration. The experiments are discussed with respect to new (unpublished) electrophysiological recordings from disparlure receptor cells in both species. Special attention is given to the supposed masking effect of the disparlure precursor (an olefin). This substance is ineffective as an attractant, but has been reported to reduce the attraction of gypsy moth males to disparlure or to live females. However, the olefin elicits excitatory reactions in the same type of receptor cell that responds to disparlure and the related epoxides. Furthermore, no masking of the electrophysiological response was observed with the receptor cells when the olefin was added to disparlure.

The identity of the Lymantria species in the north-western Himalayas is confirmed as L. obfuscata Wlk., and not as L. dispar (L.) with which it has commonly been confused in the past. The larval and imaginal characters separating the two species are described and illustrated.

Diploid bisexual, diploid parthenogenetic, and tetraploid parthenogenetic races are known to exist in the psychid lepidopteran, Solenobia triquetrella. When tetraploid females are crossed with diploid males, triploid intersexes result. In the present analysis the antennae of females of all three races were compared with those of males and of intersexes, using the following parameters: length of the antennae; number, length, surface, and volume of their segments; length, arrangement, size, shape, and surface configuration of scales and bristles. Correlations between these properties and between the left and right antenna of individuals were determined. The results show that the antennae of intersexes display a chaotic mosaic of male and female characteristics and areas, which supports the following thesis expressed by the author in earlier investigations: during intersexual development male and female determining factors are active simultaneously; each cell is determined to become either entirely female, or entirely male. The so-called time-law of intersexuality as postulated for Lymantria by Goldschmidt does not apply.

SevenLymantria spp. viruses from widely separated sources were used in a screening test for virulence. Laboratory data show thatLymantria dispar L. cytoplasmic-polyhedrosis virus of Japan, and the nuclear-polyhedrosis virus of Connecticut (U.S.A.) are more virulent than other five viruses when tested on the larvae of the gypsy moth. The nuclear-and cytoplasmic-polyhedrosis viruses ofLymantria fumidaBtl. were also infectious forL. dispar larvae.

Gypsy moth larvae, Lymantria (= Porthetria ) dispar , were exposed in woodlands by tethering them with threads to the trunks of oak trees to obtain information about the diel periodicity of ovipositional activities of the parasite, Parasetigena silvestris (= agilis ) (Robineau-Desvoidy). Also investigated was the ovipositional response of the parasite to different host models exposed in the same way. P. silvestris laid the most eggs during the afternoon and early evening hours; practically no eggs were laid at night. Females attacked previously-parasitized hosts as well as non-parasitized ones, but did not lay eggs on dead, freeze-dried caterpillars unless they were not attached to the substrate, and so, movable by wind.

The sex attractant emitted by the female gypsy moth has been identified as cis-7,8-epoxy-2-methyloctadecane. The structure was verified by spectral, gas chromatographic, and biological comparisons with the synthesized compound. Nine closely related isomers were considerably less effective.

On 20 September 1980 a single male gypsy moth, Lymantria (= Porthetria) dispar (L.), was found in a pheromone trap near the Arts and Culture Centre, Corner Brook, Newfoundland. Identification was confirmed by Dr. J. D. Lafontaine, Biosystematics Research Institute, Ottawa. This was the first record of the gypsy moth in Newfoundland, which is separated in the south 144 km from Nova Scotia and in the north 14 km from Labrador.

DURING a recent visit to Madrid for another purpose, I was able to visit some of my colleagues there, and was delighted to find that research work in genetics was continuing. Prof. I. de Zulueta, in the intervals of hiding the more precious contents of the biological museum in cellars, was continuing his work on the polymorphic beetle Phytodecta variabilis. Prof. Galan, of Salamanca, was very appropriately breeding the explosive cucumber, Ecballium elaterium. This plant is hermaphrodite in one half of Spain, di” cious in the other. Crosses between a di” cious plant and hermaphrodites from different areas seemed to reveal the existence of strong and weak local races, differing, like those of Lymantria, in respect of sex-determining factors.