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Experiments were conducted to investigate oviposition and host selection by Stenobracon deesae (Cam.), a Braconid parasite of certain Lepidoperous borers of sugar-cane, maize and sorghum in India. The fecundity and sex-ratio of this parasite and the duration of its life-cycle were also studied.Chilo zonellus (Swinh.) and Corcyra cephalonica (Staint.) were used as hosts. The former is one of the principal hosts in the field, but the latter is not normally a host of this parasite.The femal Stenobracon normally avoids laying eggs on hosts that are already parasitised by its own kind when unparasitised hosts are available; but in the absence of healthy hosts or when these are too crowded, parasitised hosts are attacked by it.At a temperature of 26°C. and relative humidity of 75 per cent., the life-cycle of the parasite was completed, on an average, in 23·3 days, but under laboratory conditions at Delhi it took 14·1 days in June-July and 43·7 days in November-December. The average duration of adult life of females in June-February, mainly in ordinary laboratory conditions, was 35·7 days, and single females lived as long as 122 and 128 days. The adult male lived for 42·7 days on the average.In the laboratory, the female lays about 24 eggs on an average, but only about one-third of them yield adults.Males predominate. The sex-ratio appears to vary according to the host; among adults reared on Chilo larvae, 28·8 per cent. were females, but among others reared on Corcyra larvae, only 6·2 per cent. were females.The phenomena of discrimination between parasitised and unparasitised hosts and of the change of sex-ratio with change of host are discussed. It is suggested that the ovipositor enables the parasite to recognise the host and that the stimuli received by the ovipositor from the host influence the functioning of the spermatheca which in turn controls fertilisation and finally the sex of the progeny.

Laboratory studies were undertaken to find out if the increased degree of infestation by certain moth species, Cadra cautella (Wlk.), plodia interpunctella (Hb.) and Corcyra cephalonica (Stnt.) following the chemical control of beetles including Tribolium castaneum (Hbst.) in stacks of groundnut (Arachis) in Nigeria could be due to relaxation of inter-specific competition.All test insects were reared and studied at a constant temperature of 25.5°C. and 70 per cent. ralative humidity. All experiments were conducted on shelled nuts (or germs of nuts) in specimen tubes, crystallising dishes or jam jars. The survival and development of the immature stages of the moth species was studied and the numbers of eggs laid by the adults recorded in the presence of adults of T. castaneum; the reciprocal effects of moth larvae on T. castaneum were also briefly studied.The most important harmful effects of T. castaneum were on copulating moths and on moth eggs. Adults were frequently disturbed and sometimes killed or, if they survived, laid fewer eggs; eggs were also eaten, especially those laid loose in the medium. Adults of T. castaneum also attacked and killed moth larvae and pupae, but this was considered to be of minor importance. The silk produced by moth larvae was inimical to larvae of T. castaneum, but the effect on the population of T. castaneum was probably offset by the beneficial effect of moth cocoons, which provide shelter for larvae of T. castaneum from cannibalism.It is conculaded that as a result of competition for food and/or space between T. castaneum and the moth species the moth populations are likely to be exterminated despite their apparently higher intrisic rate of increase.

The larvae of Corcyra cephalonica Staint and Tribolium castaneum Herbst were allowed to grow in media containing radioactive tricalcium phosphate compounds— 45 Ca or 32 P prepared in the laboratory. Haemolymph and muscle-cuticle complex showed high accumulation of 45 Ca and 32 P. The radioactivity retained by the tissues increased with time and was highest between 24 and 72 hr. Considerable radioactivity was still detected even 6 days after shifting the Corcyra larvae to a non-radioactive medium. The results indicate that the inhibitory effects reported earlier are a result of uptake of the compound and not due to inanition.

The synthesis of a number of compounds containing mostly a chlorobenzene nucleus as the toxic grouping and a CCl2 (as CHOH·CC13, COCC13, O·COCC13 or > CHCC13) or a COCH3 group as the chief lipoid-soluble component, has been described by the authors in the earlier papers of this series.2, 3, 4, 5 This paper incorporates the results of the investigation of the insecticidal action of 35 of those compounds (containing a combination of a lipoid soluble and a toxic grouping), on the rice-moth Corcyra cephalonica (belonging to the family Pyralidae, order Lepidoptera) which is very common in India, employing the technique of direct spraying. The results have been reviewed in the light of the theory of Lauger, Martin and Muller,1 correlating insecticidal action and chemical constitution. A few generalizations pertaining to the effect of some individual groups on the toxicity of a molecule have been put forward. It is concluded that, apart from the presence of a toxic and a lipoid-soluble grouping, certain other factors of yet unknown nature also play an important role in conferring high insecticidal activity.

A method has been standardized to estimate small quantities of food intake by larvae fed on flours using diets mixed with calcium phosphate labelled with 45calcium. Employing this method, the early instar larvae of Corcyra cephalonica and Tribolium castaneum were found to consume more diet per unit weight than the older ones. Pyrethrum and zirum mixed with the diets at 1 to 3 per cent levels inhibited the diet intake of C. cephalonica larvae.

Literature, mainly Indian, pertaining to the recorded hosts ofBracon hebetorSay andB. brevicornisWesm., and on the taxonomy of the two species, has been reviewed. Observations on different morphological characters, including the male and female genitalia, which have been used in establishing the identity of the two species, have been made. A large number ofB. hebetorspecimens reared in Bangalore onCorcyra cephalonica(Stnt.),Ephestia cautella(Wlk.),Adisura atkinsoniMoore and those collected in food-grain godowns, and ofB. brevicornisreared onC. cephalonicaandE. cautellain Bangalore, onNephantis serinopaMeyr. from Coimbatore (South India), onPyrausta nubilalis(Hb.) from Canada and on cotton bollworms (?) from Delhi (North India), have been examined.Differences in colour, relative proportions of antennal joints and punctation on the abdomen have been found to be variable and as such are not to be depended upon for distinguishing the two species. The number of antennal joints which has hitherto been considered to be the decisive character by which the two species may be separated is also not reliable as there is a wide range of variation even in the progeny of a single pair of parents. Above all, the fact that the two species interbreed and give rise to fertile offspring, which also show a fairly wide range of variation in the number of antennal joints, proves that the two are identical, and there is no ground to treat them as two distinct species, at least so far as the Indian specimens are concerned, for whichBracon hebetorSay is the valid name.

A laboratory study of the biology of Corcyra cephalonica (Staint.) was made at 30°C and 70% r.h. on sorghum. The number of eggs laid per female, oviposition period, development time and survival from egg to adult were determined. The data were used to estimate the finite rate of increase and the intrinsic rate of natural increase of the moth. For the finite rate of increase (λ) the estimated value was 18 per lunar month, corresponding to an intrinsic rate of natural increase ( r ) of 2.9. The results are compared with published data and it is concluded that the pest potential of C. cephalonica has been, hitherto, underestimated.

(1985). A Note on the Effective Dosages of Some Fumigants Against Certain Stages of Corcyra Cephalonica Staint II. East African Agricultural and Forestry Journal: Vol. 51, No. 2, pp. 116-118.

Experiments were conducted to check the suitability of spent or dead Corcyra cephalonica (Stainton) moths as food for mass rearing of Chrysoperla carnea Stephens. The results revealed that use of this foodstuff resulted in substantial increase in larval and pupal durations of C. carnea . Survival rates of larvae and pupae were also lowered and the adults failed to lay viable eggs. Therefore, this food material was found to be an inadequate source of nourishment in mass multiplication programmes of C. carnea .

SummaryTissues of Corcyra cephalonica and serum of albino rats fed a diet containing gammexane accumulated more free cholesterol with concomitant decrease in ester fraction. Inositol almost completely counteracted the effect of gammexane. Inositol thus appears to have great influence on esterification of cholesterol.

Laboratory investigations of mating behavior in the rice moth, Corcyra cephalonica Stainton (Lepidoptera: Pyralidae; Galleriinae) showed that male moths are attracted at short range to live, virgin female moths and to female abdominal-tip extract. Volatiles collected from virgin female moths contained one component eliciting an electroantennographic (EAG) response from the male moth, and the chemical, spectroscopic, and chromatographic data on this component were consistent with that of synthetic 6,10,14-tri- methyl-2-pentadecanol. This compound caused an EAG response from the male moth and attracted male moths in the bioassay. The pheromone is thought to play a role in courtship, and the synthetic material was shown to cause the male moths to search for a mate and attempt copulation.

Durch Messung der pro Zeiteinheit aufgenommenen Trockensubstanzmenge, der Uberfuhrungskonstante des inerten Markers152Eu in den Kot und dessen Verzogerunszeit bis zur erstmaligen Exkretion liess sich bei zwolf 78 Wochen alten Bullen die Trockensubstanzmenge im Pansen sowie im Gastrointestinaltrakt ermitteln.

SummaryThe range of toxicity of Co and Ni to Corcyra larvae has been determined. It has been shown that under conditions wherein excess Co, Ni and Zn produce severe inhibition of growth in these larvae, supplementation with Fe uniformly restores growth to normal in all 3 metal toxicities and that Mg is effective only in Co and Ni toxicities. The significance of these results in relation to metal interrelationships in Corcyra larvae has been discussed.

The leaves of Moringa oleifera are increasingly used as a food supplement in several countries due to their nutritional composition, which is rich in protein, vitamins, and mineral salts. Foodstuffs can be damaged by several pests when stored in environments with temperatures that are favorable to insect development; therefore, the susceptibility of M. oleifera leaves to attacks of moths that feed on stored products was tested. Tests were carried out on Pyralid Cadra cautella, Corcyra cephalonica, and Plodia interpunctella, as well as Geometrid Idaea inquinata, which were reared on dried whole or powdered M. oleifera leaves, an artificial diet, or an artificial diet supplemented with dried or powdered leaves. The numbers of adults and the development periods with the different diets were recorded. M. oleifera leaves were unsuitable as a rearing medium for all of the species except I. inquinata, although only a few individuals of this species reached the adult stage. The use of an artificial diet of which one-quarter consisted of dried and powdered leaves did not affect the number of progeny or on the biological cycle, showing that the effect was due to the nutritional composition, as well as to the toxic effect. The storage of M. oleifera as powdered leaves is recommended in order to preserve the nutritional characteristics and avoid damage caused by moth larvae.

We conducted an experiment in Niger to evaluate the performance of hermetic triple layer (Purdue Improved Crop Storage- PICS) bags for the preservation of shelled and unshelled groundnut Arachis hypogaea L. Naturally-infested groundnut was stored in PICS bags and woven bags for 6.7 months. After storage, the average oxygen level in the PICS bags fell from 21% to 18% (v/v) and 21%-15% (v/v) for unshelled and shelled groundnut, respectively. Identified pests present in the stored groundnuts were Tribolium castaneum (Herbst), Corcyra cephalonica (Stainton) and Cryptolestes ferrugineus (Stephens). After 6.7 months of storage, in the woven bag, there was a large increase in the pest population accompanied by a weight loss of 8.2% for unshelled groundnuts and 28.7% for shelled groundnut. In PICS bags for both shelled and unshelled groundnuts, by contrast, the density of insect pests did not increase, there was no weight loss, and the germination rate was the same compared to that recorded at the beginning of the experiment. Storing shelled groundnuts in PICS bags is the most cost-effective way as it increases the quantity of grain stored.

Insect larvae respond differently to juvenoid treatment. Larvae occurring in relatively constant ecological conditions with abundant food, e.g.Trogoderma granarium, Tribolium castaneum, Corcyra cephalonica andEphestia cautella, can undergo several extra larval moults, show growth with each moult, may moult 2–3 times with 1 treatment and do not suffer ecdysial failure. Larvae adapted to changing ecological conditions, e.g.Spodoptera litura, Earias fabia, Papilio demoleus, Euxoa spinifera andAttacus ricini, rarely undergo supernumerary moults, and the supernumerary instars suffer from ecdysial failure. It is suggested that the former have evolved an endocrinological adaptation.

Among the diverse forms of insect life infesting stored agricultural products in South India those belonging to the Lepidoptera are by no means unimportant. Though no accurate estimates of the annual losses in value of grain, pulses, etc., due to their depredations are available in this country, it has to be admitted that the extent of the damage may occasionally be considerable. It is, therefore, unfortunate that these insects have not attracted sufficient attention at the hands of Economic Entomologists in this country; consequently very little information is available as to the exact identity of the species, their relative importance, or their life-histories. The present investigation was undertaken to make a detailed study of this problem in South India with a view to elucidating the points just raised.

DURING the course of the nutritional studies1 on the rice moth, Corcyra cephalonica Staint., to determine the comparative value of several commercially available antibiotic feed supplements, it was observed that in some cases male moths of Corcyra cephalonica Staint. exhibited a higher growth response than the females receiving dietary antibiotics in their larval stages. A survey of the literature failed to disclose specific observations on this phenomenon among insects, although Palafox and Rosenberg2 observed that male chicks respond in a more satisfactory manner to antibiotic feed supplements than the female.