Functional organization of the tympanal organ of the flour moth, Ephestia kuehniella

Data about electrical recordings from the tympanic organ of the flour moth, Ephestia kuehniella, to acoustic stimuli is presented. The stimuli had a frequency that ranged from 5 to 100 kHz, with minimal intensities of 40 to 50 db (Odb = 0.0002 dynes/cm²) and maximal up to 110 db. The tympanic organ of E. kuehniella responded in the whole range of frequencies used and showed two sensitivity maxima, one at 20 kHz and the other at 60 kHz. It responded from 45 to 110 db. The electrical activity of the tympanic nerve consisted of a spontaneous discharge of a type B cell and a tonic discharge in response to acoustic stimulation, produced by four acoustic sense cells, called A₁, A₂, A₃, and A₄. All these acoustic sense cells respond in the whole frequency range used and they differ in the heights of their action potentials and in their sensitivity to acoustic stimuli. The possible biological significance of hearing in pyralid moths is discussed.     

Cocoon spinning behaviour in Ephestia kuehniella; Correlation with endocrine events

The cocoon spinning behaviour in Ephestia kuehniella Zell. consists of two phases: construction of the outer envelope and spinning of the inner envelope. The first phase can be modified by tactile stimuli received from the surroundings, whereas the second phase is fixed rigidly and probably under the control of the hormones associated with pupation.     

Interorder transfer of mycoplasma-like microorganisms between Drosophila paulistorum and Ephestia kuehniella: Tissues,dosages, and effects

Testis and head extracts of sterile male intersemispecific hybrid Drosophila paulistorum are pathogenic when injected into Ephestia kuehniella larvae. The time and frequency of death of the recipients is a function of the extract concentration. Extracts of Ephestia recipients are pathogenic and will kill E. kuehniella larvae and D. paulistorum adults. Larval Drosophila recipients of these extracts survive through pupation. A majority of these recipients fail to eclose. Those animals which do survive to the adult stage and which are fertile demonstrate the same pattern of sterility among their progeny as is found in D. paulistorum hybrids and recipients of D. paulistorum extracts. The results indicate that the pathogenicity of the extracts is due to the mycoplasma-like microorganisms which are responsible for the male intersemispecific hybrid sterility in D. paulistorum. The mycoplasma-like microorganisms grow rapidly in E. kuehniella hosts, with a division time of approximately 1.8 hr, and they retain their host specificity for the semispecies of D. paulistorum.     

The regulation of development during diapause in Ephestia elutella (Hübner) by temperature and photoperiod

Diapausing larvae of Ephestia elutella reared at 20°C in short photoperiods (LD 11:13), and then maintained 12 weeks or longer at 5–15°C before transfer to 20 or 25°C, pupated sooner than unchilled controls. At 25°C, all samples kept in long photoperiods (LD 15:9) survived better and pupated faster than similarly treated samples held in short photoperiods (LD 9:15). Samples kept at 20°C after chilling pupated much slower than those at 25°C, and, except after exposure at 5°C, pupated at similar rates at LD 11:13 or 15:9, although mortality was higher at the shorter photoperiod. After exposure at 5°C, larvae required increased day-length as well as increased temperature to hasten pupation whereas after exposure at 10°C most responded to increased temperature only.For samples maintained in slightly heated or unheated outbuildings, the summer emergence was poorly synchronized and males on average emerged ahead of females. Samples moved from the unheated outbuilding to 25°C and long days in the laboratory in early spring, however, pupated quickly and males and females emerged together. A late phase of diapause development thus exists requiring both high temperature and long photoperiods to ensure a prompt resumption of morphogenesis. Spring temperatures in the United Kingdom are seldom high enough to synchronize the completion of diapause.     

Modification of responses to sex pheromone in the male Mediterranean flour moth, Ephestia kuehniella, by additional substances

Fourteen substances were tested as vapour for the ability to modify the wing vibration response of male Ephestia kuehniella to sex pheromone from the female over a period of 30 sec. Eleven substances had little or no effect on behaviour when tested alone, but six of the eleven decreased the response to pheromone, one increased it, and four had no effect. Two substances were tested in a wind tunnel for their effect as background vapour on the number of male E. kuehniella present at a source of female sex pheromone over a period of 18 min. The effects of these substances in the wind tunnel were the inverse of their effects in the experiments on wing vibration, that is, the short-term measurements of wing vibration gave no indication of the influence of these substances on the accumulation of males at a source of female sex pheromone.

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Zusammenfassung In einer Zeitspanne von je 30 sec wurden 14 Stoffe in Dampfform auf ihre Fähigkeit geprüft, die Flügelschwirr-Reaktion der männlichen Ephestia kuehniella in Gegenwart des weiblichen Geschlechtspheromons zu verändern.Wenn 11 dieser Stoffe ohne Beigabe des weiblichen Geschlechtspheromons untersucht wurden, ergab sich wenig oder gar keine Wirkung auf das Verhalten der männlichen Tiere; in Gegenwart von weiblichem Geschlechtspheromon verminderten dagegen 6 dieser Stoffe das Verhalten der Männchen gegenüber diesem Pheromon, ein Stoff erhöhte die Reaktion und 4 Stoffe hatten keine Wirkung.In einer Zeitspanne von je 18 min wurden 2 Stoffe als Hintergrunddampf in einen Windkanal gebracht und untersucht, ob sie die Zahl der Männchen von E. kuehniella beeinflussen können, die sich an der Quelle des weiblichen Geschlechtspheromons sammeln.Die Wirkung dieser Stoffe im Windkanal stand in umgekehrtem Verhältnis zu ihrer Wirkung im Flügelschwirr-Experiment, das heißt, die kurzfristigen Messungen des Flügelschwirrens ergeben keinen Hinweis auf die Einwirkung dieser Stoffe auf die an der Quelle des weiblichen Geschlechtspheromons angesammelte Zahl der Männchen.

     

The ecdysteroid titres during the last-larval instar of Ephestia kuehniella Z. (Lepidoptera: Pyralidae)

The ecdysteroid titre and the body weight during the last-larval instar of Ephestia kuehniella were determined. Slightly elevated ecdysteroid titres occur during the first 12 h following the last larval-larval ecdysis (38 ng/g) and again some 120 h later, lasting about 48 h (33 ng/g). A high ecdysteroid peak (750 ng/g) with a maximum in prepupae of the eye-class A4 precedes the larval-pupal ecdysis. The basal levels between these increased ecdysteroid titres are between 13 ng/g and 15 ng/g. Compared with the body weight, the first sligtly increased ecdysteroid titre 12 h after ecdysis is associated with the beginning of food intake, the second increase at 144 h after ecdysis with reduced gain in body weight. The prepupal ecdysteroid peak occurs whilst the body weight remains constant. Correlations between the varying ecdysteroid titre and morphological and physiological events accompanying the progress in larval-pupal development are discussed.     

Behaviour of the male mediterranean flour moth, Ephestia kuehniella, following attraction to a source of female sex pheromone

Filter paper treated with an extract of virgin female Ephestia kuehniella was held in a stream of air, and its characteristics as a source of sex pheromone were inferred from a series of bioassays of the air stream. Air swept upwards through the entire cross section of an olfactometer chamber which held male E. kuehniella and filter paper treated with female extract was placed under the chamber to provide sex pheromone from a defined area on the floor (the target). Time-response curves were plotted for a range of quantities of female extract at the target. Males flew to the target but often left and returned. The number of males on the target at any instant therefore represented a dynamic equilibrium between their rates of arrival and departure.

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Zusammenfassung Filtrierpapier, das mit einem Extrakt weiblicher Mehlmotten behandelt war, wurde so in einen Luftstrom gebracht, daß seine Eigenschaften als Geschlechtspheromonquelle in einer Reihe von biologischen Experimenten in strömender Luft ermittelt werden konnten. Die Luft wurde durch den gesamten Querschnitt der Olfaktometerkammer, welche die Männchen enthielt, aufwärts geleitet, unter der das Filtrierpapier so angebracht war, daß am Boden eine Fläche definierter Größe als Geschlechtspheromonquelle entstand. Für eine Reihe verschiedener Weibchenextrakt-Konzentrationen auf der Lockfläche wurden Zeitreaktionskurven aufgestellt. Die Männchen flogen das Ziel an, verließen es oft wieder und kehrten dann wieder zurück. Die Anzahl der in jedem einzelnen Augenblick auf der Lockfläche anwesenden Männchen stellt daher ein dynamisches Gleichgewicht ihrer Anflug- und Abflugraten dar.

     

Brain-independent development in the moth Sesamia nonagrioides

The caterpillars of Sesamia nonagrioides developing under long-day (LD) photoperiod pupate in the 5th or 6th instar whereas under short day (SD) conditions they enter diapause and undergo several extra larval molts. The diapause is terminated within 1-3 instars upon transfer of SD larvae to the LD conditions. Brain removal from the 6th instar larvae promotes pupation followed by imaginal development; however, one third of the SD larvae and 12% of the LD larvae debrained at the start of the instar first undergo 1-2 larval molts. The incidence of larval molts is enhanced by the brain implants. Exclusively pupal molts occur in the LD larvae debrained late in the 6th instar. Decapitation elicits pupation in both LD and SD larvae, except for some of the 4th and 5th and rarely 6th instar that are induced to a fast larval molt. The pupation of decapitated larvae is reverted to a larval molt by application of a juvenile hormone (JH) agonist. No molts occur in abdomens isolated from the head and thorax prior to the wandering stage. Abdomens isolated later undergo a larval (SD insects) or a pupal (LD insects) molt. Taken together the data reveal that in S. nonagrioides (1) several larval molts followed by a pupal and imaginal molt can occur without brain; (2) an unknown head factor outside the brain is needed for the pupal-adult molt; (3) brain exerts both stimulatory and inhibitory effect on the corpora allata (CA); (4) larval molts induced in CA absence suggest considerable JH persistence.     

Influence of host plants on development, fecundity and egg hatchability of the arctiid moth Diacrisia casignetum

Measurements were made of the differences between sunflower and climbing hempweed leaves for development, fecundity and egg hatchability of Diacrisia casignetum Kollar. Developmental time and weight gains of sunflower-fed larvae were respectively longer and greater than those of hempweed-fed ones. The development time and weight gain, attributable to differences in host plants, were statistically heterogeneous (P<0.05-<0.10). Relative fecundity and egg hatchability of sunflower reared insects were greater than those of hempweed reared ones, and these were also statistically heterogeneous (P<0.1 and <0.05, respectively). Hempweed leaves contained relatively high titres of phenols and low ratios of proteins to phenols. Ovaries were heavier in insects reared on sunflower than on hempweed, whereas the level of phenols incorporated into the ovary was higher in insects fed on hempweed than those on sunflower. The differences in these parameters may be due to variations in nutritional quality of these hosts and incorporation of ingested phenolic materials to ovary and insect biomass.

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Résumé L'étude a porté sur l'évaluation de l'influence des feuilles de tournesol (Helianthus annuus) et de Mikana cordata sur le développement, la fécondité et l'éclosion des oeufs de D. casignetum Kollaz. La durée de développement et le gain de poids sur tournesol étaient plus importants que sur M. cordata. La durée de développement était statistiquement hétérogène (P<0.05), ce qui peut être dû à des différences entre plantes. La fécondité et le taux d'éclosion chez les insectes élevés sur tournesol étaient plus élevés que ceux observés sur M. cordata, dont les résultats étaient aussi hétérogènes (P<0.1 et<0.05 respectivement). Les feuilles de M. cordata contenaient des taux relativement élevés de phénols et des rapports protéines sur phénols bas. Tout ceci suggère que les différences observées sont attribuables à des variations dans la qualité nutritive de ces hôtes et dans l'incorporation à la biomasse de l'insecte de matériaux phénologiques ingérés.

     

Responses of the cinnabar moth Hypocrita jacobaeae to various temperature/photoperiod régimes

Subjecting larvae of Hypocrita jacobaeae to temperatures of 21 and 28°C and photoperiods of $\text{0}\text{24}$, $\text{10}\text{14}$, $\text{12}\text{12}$, and $\text{18}\text{6}$ does not interfere with the phenomenon of diapause. The last larval instar is particularly affected by the higher temperature. Effects include numerous deaths, a high proportion of ill-formed pupae, and failure of adults to emerge properly from the pupal case. The significance of these findings is discussed.     

Effect of selected pseudoguaianolides on survival of the flour beetle, Tribolium confusum

Four pseudoguaianolides, parthenin, helinalin, coronopilin and tenulin, were tested for their effects on survival of the confused flour beetle, Tribolium confusum. Tenulin had no significant effect in concentrations tested but the other three compounds significantly reduced survival of the beetles when present in food in concentrations higher than 3.0%. It is suggested that the α-methylene-γ-lactone moiety (absent in tenulin but present in the other three lactones) is responsible for the detrimental properties of selected pseudoguaianolides on survival of flour beetles, whereas the α-β-unsaturated ketone functionality (present in tenulin, parthenin, and helenalin)does not contribute to those properties.     

Effect of synthetic B-vitamin and natural enrichment of flour on larval development and fecundity of Tribolium confusum and T. castaneum

Larval developmental time and adult fecundity of the flour beetles Tribolium confusum and T. castaneum were measured on twelve different diets: top patent fluor; top patent flour enriched with riboflavin, thiamine and niacin, singly or in combinations; top patent flour mixed with bran, germ or both; and whole wheat flour.Larval mortality did not exceed 5% on any of the diets. Larvae of both species developed slightly faster and laid significantly more eggs in flour enriched with the three vitamins than in unenriched patent flour. The improvement was due to the addition of riboflavin. The addition of thiamine or niacin or both did not accelerate development or increase fecundity. It was concluded that top patent flour contains enough thiamine and niacin but not enough riboflavin for proper growth and development of flour beetles.Whole wheat flour was the best diet for T. castaneum, and the flour-germ-bran mixture for T. confusum. Larvae of T. confusum developed as rapidly in the mixture, as in whole wheat flour, but the adults laid significantly more eggs. T. castaneum was equally fecund on these diets, but developed faster in the coarser whole wheat flour. In both species, especially T. castaneum, dietary components had a greater effect on fecundity than on rate of larval development.

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Résumé Le taux de développement larvaire et la fécondité des sujets adultes du Tribolium brun de la farine, Tribolium confusum Jacquelin duVal, et du Tribolium rouge de la farine, Tribolium castaneum Herbst, ont été examinés en rapport avec 12 formules alimentaires différentes: fleur de farine; fleur de farine enrichie de riboflavine, de thiamine et de niacine, seules ou combinées; fleur de farine mélangée de son, de germe de blé ou de ces deux éléments à la fois; enfin, farine de blé entier.Dans chacun de ces régimes, la mortalité larvaire n'a jamais été supérieure à 5%. Les larves de ces deux espèces se sont developpées légèrement plus vite et ont pondu beaucoup plus d'oeufs avec le régime de fleur de farine enrichie de trois vitamines qu'avec le régime de fleur de farine non enrichie. Ces améliorations du développement sont dûes à la riboflavine, car l'addition de thiamine ou de niacine, seules ou associées, n'a ni accéléré le développement ni augmenté la fécondité. On en a conclu que la fleur de farine contenait assez de thiamine et de niacine, mais qu'il y avait une insuffisance en riboflavine pour assurer le développement et la croissance des Tribolium spp.La farine de blé entier a été la plus efficace pour les T. castaneum, et le mélange de farine, de germe et de son a eu les mêmes effets sur les T. confusum. Les larves des T. confusum se sont développées au même rythme dans ce mélange que dans la farine de blé entier, toutefois les sujets adultes ont pondu une quantité d'oeufs beaucoup plus grande dans ce même mélange. Les T. castaneum étaient également féconds dans ce mélange, mais se sont développés plus rapidement dans la farine plus grossière de blé entier.Pour les deux espèces, mais spécialement pour les T. castaneum, les composants du régime ont eu un plus grand effet sur la fécondité que sur le développement larvaire.

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Contribution No. 708 of the Canada Agriculture Research Station, Winnipeg.     

Growth and development of the Angoumois grain moth, Sitotroga cerealella in an artificial diet

A simple method for rearing the Angoumois grain moth, Sitotroga cerealella, in an artificial diet is described. Although the larvae normally feed within grain kernels, they readily became established in pellets containing a mixture of five natural products. An evaluation of the growth rate in this medium revealed a marked sex difference. The males attained a maximum mean larval weight of 7·2 mg at 22 days compared with 12·3 mg for mature females at 24 days. Both sexes were found to pass through four larval instars. A study of the pupation rate showed that males reached 50 per cent pupation a full 5 days before females. While both sexes spent about 6·7 days in the pupal-pharate adult stage, the mean weight of newly-ecdysed female adults was 77 per cent greater than that of the males.     

Effect of temperature and photoperiod on the induction of diapause in the mite Metaseiulus occidentalis

Diapause in a predaceous mite, Metaseiulus occidentalis, from a Californian vineyard population is a photoperiodically induced, facultative, adult reproductive diapause in females. The laboratory-determined critical photophase at 19°C was estimated at 11·2 hr. At 16°C, the critical photophase under laboratory conditions was approximately 11·6 hr. Temperature influenced the photoresponse of M. occidentalis so that diapause was entirely averted at temperatures of 22, 25, and 30°C. Aestival diapause at higher temperatures and long photophases was lacking. Development was continuous under constant darkness at all the temperatures tested. Diapause termination in laboratory-reared mites occurred spontaneously under the inductive conditions. Under constant 19°C temperatures, females responded to photophases so that diapause was terminated most rapidly under a 16 hr photophase (in 18·6 days); the 12 and 8 hr photophases, at this temperature, were next in their effectiveness, with 27·9 and 73·0 days, respectively, required for termination.     

Lysozymelike lytic enzyme of Streptococcus faecalis and its role in the larval development of wax moth, Galleria mellonella

The predominant type of bacteria present in the gut of larval Galleria mellonella were streptococci group D identified as Streptococcus faecalis which showed bacteriolytic activity. Young larvae usually contained mixed populations with a marked dominance of fecal streptococci while normally developed mature larvae most frequently contained large uniform populations of S. faecalis. Pupal stages were found to contain the highest percentage of individuals with pure cultures of fecal streptococci.The author suggests a hypothesis that, owing to its bacteriolytic properties, S. faecalis can be considered as a component of the natural, nonspecific defense mechanism of G. mellonella against bacterial infections. The lytic enzyme released in the exponential growth phase of S. faecalis participates in the selection process stabilizing the microbial flora of wax moth larvae; it limits the population of other forms of bacteria. Larval resistance to bacterial infections to a large extent depends on the magnitude of the populations and thus on S. faecalis muramidase concentration. Bacterial lysozyme inhibited the growth of the ingested organisms and in consequence it prevented the proliferation of undesired bacteria in the digestive tract of Galleria larvae.The lytic enzyme proved to be identical with autolysin, a β-N-acetylmuramide glycanhydrolase (EC 3.2.1.17) which has been isolated from trypsin-speeded wall autolysates of S. faecalis by Shockman and Cheney (1969).     

光周期和温度对中华通草蛉成虫生殖的影响

研究表明,在25℃和长光周期（L：D＝15：9）条件下饲养至产卵高峰的中华通草蛉成虫,经短光周期（L：D＝9：15）处理后,与长光周期相比,虽然产卵速度有所下降,但产卵期延长,产卵量明显提高;在15℃和短光周期条件下处理后,成虫的生殖受到强烈抑制,产卵速度显下降,部分个体逐渐停止产卵,并进入滞育状态。     

Effect of daylength and temperature on the larval diapause of the sunflower moth, Homoeosoma electellum

The effect of daylength and temperature on the regulation of the larval diapause of a central Missouri population of the sunflower moth, Homoeosoma electellum, was examined. Fully grown fourth-instar larvae exhibit a facultative diapause. Measurements of the effect of photoperiod on diapause induction revealed critical photoperiods of about 13 h 30 min light/day at 20°C, and between 11 h 45 min and 12 h light/day at 23°C. Third and fourth-instar larvae were shown to be the main sensitive stages for diapause determination. Daylength was also shown to be an important regulator of the rate of diapause development. A short day of LD 10:14 h permitted only a low rate of diapause development, whereas long days of LD 14:10 h and LD 16:8 h accelerated diapause development at 25 and 30°C. When long days were alternated with short days at 30°C the accelerating effect of long days on diapause development was not found. Systematic transfers of chilled diapausing larvae revealed an accelerated diapause development in groups transferred from 10 to 30°C LD 10:14 h, but diapause development was not accelerated in groups transferred from 10 to 30°C LD 16:8 h.     

Effect of ecdysterone on spermatogenesis in the diapausing slug moth pharate pupa, Monema flavescens

The testes obtained from diapausing slug moth pharate pupa, Monema flavescens, were cultivated in the synthetic medium of CSM-2F to investigate the hormonal regulation of the spermatogenesis. The results of this study show that the spermatocytes developed into spermatids with the addition of ecdysterone and that the ‘naked’ spermatocytes were more sensitive than the intact spermatocytes. On the basis of these results, some problems concerned with the ‘macromolecular factor’ are discussed.     

The effect of photoperiod on the reproductive development of the northern bay scallop, Argopecten irradians irradians

One-year-old bay scallops, Argopecten irradians irradians (58 ± 2 mm, 22 ± 1 g live weight) were exposed to four replicated photoperiod treatments (24D, 8L:16D, 16L:8D, and 24L where D = dark hours, L = light hours) in order to measure the effect on gonad weight and maturation during the conditioning process. Results indicated that day-lengths of more than 8 h are necessary to promote gonad maturation in bay scallops. After 6 wk, the mean gonad weight for scallops in the 16-h and 24-h light regimes was similar at 0.6 ± 0.1 g dry weight compared to a mean of 0.2 ± 0.1 g dry weight for those in the 8-h and 0-h light regimes. Histological assessment indicated significantly more follicular tissue development in both the male and female portion of the gonad in the two longer photoperiod treatments. Overall, gamete maturity was highest for the scallops in the 16-h light regime; the incidence of mature eggs was 50% compared to 35% in the 24-h light regime, 20% in the 8-h light regime and 10% in the 0-h light regime. Assessment of feeding rates indicated no significant difference in algal cell consumption among treatments. Total dry tissue weight doubled over the 6-wk conditioning trial with no significant differences among treatments. One-year-old bay scallops appear to be non-responsive to conditions suitable for gonad maturation (i.e. appropriate temperature and food levels) unless they receive more than 8 h of light exposure. This finding has important implications for northern hatcheries which typically condition broodstock indoors during the early spring.