bluuebunny/crossref_metadata_2025_split huggingface dataset:
Observations on the ecology of Glossina morsitans submorsitans Newst. in the Northern Guinea Savannah of Northern Nigeria
Authors: Jordan A. M. 
Published: July 2009

Observations, largely based on regular catches along a fly-round, were made over the five years 1959–64 on a population of Glossina morsitans submorsitans Newst. in the Northern Guinea Savannah of Nigeria. The results showed that the largest numbers of flies were caught in the early dry season (November–January) and that, as the climate became progressively drier and more severe, fly numbers declined to reach their annual minimum at the end of the dry season or in the early rains (March–May). These results are tentatively interpreted in terms of the true density of the flies and their activity. Differences occurred between the various years, some of which could be explained by climatic differences.Of the 7,412 flies caught over the five years, 1,128 (15·2%) were females; the percentage of females was highest in the dry season, rising to a peak of 24·1 per cent, in February, and was below 10 per cent. during the wet season. Many more females were caught on the bodies of the catching team than on vegetation or the ground near the team.The flies rarely fed on civet cat (Civettictis civetta) or duiker (Cephalophus rufilatus, Sylvicapra grimmia), which were the potential hosts most frequently observed in the experimental area, but fed mainly on wart-hog (Phacochoerus aethiopicus) and man, the next most commonly observed potential hosts.During the heavy rains, males of G. m. submorsitans were evenly distributed over the fly-round, but at all other seasons they were concentrated to some extent in areas of thicker vegetation. During the dry season, pupae were found in the dry soil of forest islands and riverine vegetation in the savannah; the wet season breeding sites were not discovered. Previously published data on the resting sites and trypanosome infection rate of G. m. submorsitans in the area are summarised.The results are discussed and compared with the conclusions reached by other workers from earlier more extensive studies on G. m. morsitans Westw. in Tanganyika and on G. m. submorsitans in the Sudan Savannah vegetation zone of Northern Nigeria.
The flight activity of some East African mosquitos (Diptera, Culicidae). I.—Studies on a high steel tower in Zika Forest, Uganda
Authors: Goma L. K. H. 
Published: July 2009

A series of forty 24-hour catches was carried out at seven levels (20-ft. intervals from 0 to 120 ft.) on a steel tower in Zika Forest by means of unbaited and unlighted suction traps that acted simply as air samplers. The object was to study the general flight activity of mosquitos in a tropical forest environment from samples that would not be subject to the selective effects exercised by bait-traps and light-traps.Altogether, 4,151 mosquitos belonging to thirty-four species or species-groups were taken. Eight species, Aedes (Stegomyia) apicoargenteus (Theo.), Mansonia (Coquillettidia) aurites (Theo.), M. (C.) fuscopennata (Theo.), M. (C.) maculipennis (Theo.), M. (C.) metallica (Theo.), M. (C.) pseudoconopas (Theo.), M. (Mansonioides) africana (Theo.) and M. (M.) uniformis (Theo.), were taken in numbers sufficient for detailed analysis. By far the most abundant of these was M. aurites, comprising 55·7 per cent, of the total sample. The remaining twenty-six species together constituted only 7·6 per cent.Only 144 or 3·5 per cent, of the mosquitos taken were males; and of the females, only 19 or 0.5 per cent. were blood-fed and only 11 or 0·3 per cent, were gravid. Thus, catches in the suction traps consisted almost entirely of unfed non-gravid females. It is tentatively concluded that male mosquitos in the forest are generally very inactive in the absence of stimuli such as lights or baits. The paucity of engorged and gravid females was expected; few of these would come within range of the unlighted unbaited suction traps.Dissection of 3,072 females belonging to the eight most numerous species showed all to be inseminated. Age-composition was determined in species of Mansonia only; the majority of females in the subgenus Coquillettidia were nulliparous, whereas in the Mansonioides, nulliparous and parous females occurred in roughly equal proportions.The unlighted, unbaited suction traps caught far fewer mosquitos than did light- and bait-traps under similar conditions.In general, the vertical distributions and flight-activity cycles of the various species as indicated by the suction-trap catches differed distinctly from those indicated by bait- and light-trap catches reported by other workers. Very little activity was recorded above the forest. Although, in general, activity was irregular, three main patterns could be distinguished: largely nocturnal activity continuing up to about midday but almost completely suppressed in the afternoon, as in M. aurites, M. fuscopennata, M. maculipennis, M. metallica and M. pseudoconopas; activity spread throughout the entire 24-hour period, as in M. africana and M. uniformis; and mainly diurnal activity, as in A. apicoargenteus.
The ovarian cycle and egg stage in Leptoconops (Holoconops) becquaerti (Kieff.) (Diptera, Ceratopogonidae)
Authors: Linley J. R. 
Published: July 2009

Leptoconops becquaerti (Kieff.) is one of the most troublesome species of biting midge in Jamaica. The gonotrophic cycle in this insect was studied and is described. In this species a single blood-meal is sufficient for the development of the ovaries and the maturation of eggs.The stages in follicle development and digestion of the blood-meal adopted for other blood-sucking Diptera have been applied to L. becquaerti with slight modifications. A high degree of gonotrophic harmony is present in this insect.Fully fed females were kept at five temperatures, 68, 77, 85, 91 and 98°F., to determine the time taken for the ovarian follicles to reach Stage V of development (egg mature, chorion present). The times were approximately 98, 64, 36, 30 and 27 hours, respectively.It was demonstrated that the number of ovarioles in L. becquaerti was proportional to the size of the individual (as measured by wing length). The average number of ovarioles in an insect of wing length 0.83 mm. (the mean wing length of the population sampled) was about 103.The number of eggs matured was also proportional to wing length, and was also dependent upon the temperature at which the flies were kept. Thus at the standard wing length of 0·83 mm., the average numbers of eggs matured at the five chosen temperatures (68 to 98°F.) were 78, 85, 65, 61 and 60, respectively. Females that had matured eggs were induced to oviposit by the decapitation technique.Females provided with a source of carbohydrate (honey) during egg maturation produced slightly more eggs on the average than those fed on blood alone. The comparable figures at 91°F. in the standard individual were 65 and 61, respectively. The probable rôle of supplementary carbohydrate feeding in nature is discussed.At the five experimental temperatures the greatest number of eggs hatched on days 11, 7, 5, 4 and 4, respectively, after laying. Egg-batches used in these experiments were deposited by decapitated females, and may therefore have been laid somewhat before the usual time in nature. The percentage fertility varied between individual batches at all temperatures, but the over-all fertility was consistently high (70–75%) at the lower four temperatures, and very low (4%) at 98°F. This difference almost certainly resulted from high temperature in the latter instance. Fertility in egg-batches deposited naturally (without decapitation) was of the same order as that in batches deposited by headless females.
Biology of some ground beetles (Col., Carabidae) injurious to strawberries
Authors: Briggs J. B. 
Published: July 2009

Work at East Malling, Kent, between 1952 and 1963 on the biology of Harpalus rufipes (Deg.) (Carabidae), the strawberry seed beetle, is described in detail, and briefer notes are given on the life-histories of H. aeneus (F.), Feronia melanaria (Ill.) and F. madida (F.), which are less abundant but may also damage strawberries. Soil samples for larvae were washed over suitable sieves, those for pupae and adults were carefully searched in the field. Soil sampling showed that adults of H. rufipes colonised strawberry fields only during the fruiting period, weedy arable land and grassy situations being preferred at other times. By soil sampling, it was found that larvae of H. rufipes hatched from eggs laid in weedy soil in late summer, and evidence from pitfall trapping showed that the first two instars were sometimes active on the soil surface from August to December, before penetrating to a depth of 6–18 in. to overwinter. Development was resumed in April, but the larvae remained and the pupae were subsequently found at the overwinter depth in the soil, the larvae presumably feeding on the seed of fat hen (Chenopodium album) lodged in worm burrows. Third-instar larvae occurred from April to July, and adults emerged soon after. In the laboratory, adults lived for a further two years, hibernating in winter, and becoming active and breeding each summer. Laboratory observations on oviposition periods, fecundity and feeding were also made. Larvae, which in the field were mostly found associated with plants of fat hen, fed on germinating seeds of several plants in the laboratory but growth was most rapid when they were reared on the germinating seed of fat hen.The life-cycles and habits of the three other species are briefly described and compared with those of H. rufipes, the seasonal occurrence of the different stages in the life-cycles of all species being shown in a table.
Virus disease of the African armyworm,Spodoptera exempta(Wlk.)
Authors: Brown E. S. , Swaine G. 
Published: July 2009

Field and laboratory studies of virus disease in the armywormSpodoptera exempta(Wlk.) were carried out in East Africa in 1962–64. A nuclear polyhedrosis virus was detected microscopically in pupae, prepupae and all larval instars except the first, and was found to be widely distributed in most areas subject to outbreaks of armyworm in East Africa. The signs and course of the disease in larvae ofS. exemptaare described. Attempts made in the laboratory to infectS. triturataand other species ofSpodopterawith virus fromS. exemptafailed. In unsterile conditions of maintenance, almost all laboratory cultures from wild-caught female moths sustained heavy infections. The appearance of the symptoms of polyhedrosis was accelerated at higher temperatures, and the incidence was higher in more crowded cultures. Transmission took place from contaminated leaves to larvae and probably from one larva to another. There was evidence also of generation-to-generation transmission through the egg.The effect on polyhedra of immersion in alkali solutions was investigated; it. was found that immersion for 15 minutes in 0·2 per cent. caustic potash effectively dissolved the matrix and inactivated the virus. When all equipment was sterilised in this way (or, later, with 0·4% caustic potash) apparently virus-free cultures were obtained by rearing the larvae from wild-caught females in isolation and breeding from those that survived to become adults.The possible use of the virus for control of outbreaks of armyworm in the field is discussed; it is concluded that there is at present insufficient evidence to show whether such a measure would be effective.
Heliothis armigera (Hb.) (Noctuidae) in Western Tanganyika. II.—Ecology and natural and chemical control
Authors: Reed W. 
Published: July 2009

In Western Tanganyika, Heliothis armigera (Hb.) occurs as a major pest of cotton from February to April, but also feeds on many other host plants. The dry season (August–October) is spanned usually by diapause pupae, the moths emerging from which oviposit on a species of Gleome, on which the first generation develops, giving rise to adults in November–December. Larvae of the second generation feed mainly on early-sown maize, and it is usually those of the third and fourth generations that attack cotton. Two subsequent generations occur on a variety of host plants, including late cotton, maize and legumes. The increasing severity of the attacks of Heliothis on cotton has accompanied the replacement of sorghum by maize in recent years. Maize is not only an intermediate host on which Heliothis builds up before it attacks cotton but also a source of diapause pupae later in the season.In studies of the natural control of H. armigera, based on regular sampling of eggs and larvae on host plants in the field, the most important parasites were the Tachinids Drino imberbis (Wied.) and Goniophthalmus halli Mesnil, and field observations suggested that a species of Chrysopa (Neuroptera) was the main predator. Increasing use of insecticides may be reducing the effectiveness of natural control. A polyhedral virus was common, mainly found in larvae of Heliothis feeding on maize. The control of Heliothis on cotton by cultural methods was attempted by banning early sowing of maize and by sowing strips of maize in cotton fields as trap crops. Neither method is practicable on a large scale. Early sowing of cotton appears to be the best means of withstanding attack by Heliothis, for the local strains of cotton are able to compensate by later growth even for a very heavy Heliothis attack, provided they are sown early enough to utilise the late rains.In cotton that was subject to a heavy attack by H. armigera, five applications at 2-week intervals of DDT at 1 lb. per acre gave good control of the larvae and increased the yield from about 200 lb. seed cotton per acre to about 500 lb., the difference being mainly in the early pickings. The addition of toxaphene increased the yield, probably by controlling Earias spp., but neither toxaphene alone nor carbaryl appeared to control Heliothis. The numbers of eggs laid were higher on cotton treated with DDT than on untreated cotton.
A verandah-trap hut for studying the house-frequenting habits of mosquitos and for assessing insecticides. I.—A description of the verandah-trap hut and of studies on the egress of Anopheles gambiae Giles and Mansonia uniformis (Theo.) from an untreated Hut
Authors: Smith Alec 
Published: July 2009

A description is given of a verandah-trap hut designed to assess the egress and survival of mosquitos escaping through the eaves of the type of window-trap hut used in insecticide testing in East Africa.Fifty-one per cent. of females of Anopheles gambiae Giles in all gonotrophic stages and 19 per cent. of those recently fed left the hut each night, with 15 and 30 per cent., respectively, of the egress occurring through the eaves.Ninety per cent of females of Mansonia uniformis (Theo.) in all gonotrophic stages and 91 per cent. of those recently fed left the hut each night, with 69 and 66 per cent., respectively, of the egress occurring through the eaves.It was concluded that, owing to the high proportion of individuals of M. uniformis that leaves by the eaves, the verandah-trap hut was of a more suitable design for studying the house-frequenting habits of this species, and of other species with similar habits, than the simple window-trap hut.
The biology and phenology of Arenipses sabella Hmps. and Cadra figulilella (Gregson) (Lepidoptera, Pyralidae) on dates in israel
Authors: Kehat M. , Greenberg S. 
Published: July 2009

Larvae of Arenipses sabella Hmps., a serious pest of date palm trees in Israel, developed normally on inflorescences, immature or ripe rates and on green fruits of Phoenix canariensis, and their development at 30°C. took 34–45 days. Survival of males and fertilised famales was 10.8–12.0 days at 25°C. and 7.0–8.2 days at 27°C. No difference was found between survival of males and females, but unfertilised females lived rather longer than fertilised famales. The total production of eggs per female was 285 eggs at 25°C. and 328 at 27°C. At 25°C. 825 per cent. of the eggs were laid during the sixth and seventh nights of the female’s life, at 27°C. 74 per cent. were laid during the third and fourth nights. The total number of eggs laid by unfertilised females was lower than that of fertilised ones. The number of females fertilised was dependent on the number of males present in the rearing cage.In Israel, only two generations of A. sabella— those in the spring and in the late autumn—become sufficiently large to be of economic importance. Damage occurs during only a short period in spring, when inflorescences, toung fruits and fruit stalks are attacked. In autumn and winter most larvae enter diapause. In the laboratory, the moth passes through four generations a year and even at the relatively high temperatures maintained during the winter the larvae entered a diapause.Cadra figulilella (Gregson) is a serious pest of ripening dates in Israel and damages fruit still on the tree and also after it has been picked, if it is not then fumigated.The time taken for development at 30°C. was 54–65 days. At this temperature adults lived for 4–6 days and the average number of eggs laid per fertilised female was 160. Unfertilised females laid fewer eggs. Most of the eggs were laid during the second and third nights after emergence of the female. The number of fertilised females depended on the number of males present in the rearing cage.A few larvae were observed in the plantation in dropped, decaying dates throughout the year, but attack on the bunches started only when the fruit began to ripen.Azinophos-methyl (E.C.20%) 0.5 per cent. and diazinon (E.C.25%) 0.5 per cent. were the most effective of the compounds tested. Application when the colour of the fruit began to change and again three or four weeks later resulted in excellent control of the pset.
Laboratory culture of the rice gall midge Pachydiplosis oryzae (Wood-Mason)
Authors: Perera Nalini , Fernando Henry E. 
Published: July 2009

No method has so far been available for the laboratory culture of Pachydiplosis oryzae Wood-Mason or for the controlled infestation of rice plants with this pest. Suitable techniques for the above have been developed and are described.For the laboratory culture of P. oryzae, exposure of rice seedlings to gravid females for oviposition and the subsequent maintenance of the plants at a very high humidity in a mist chamber gave high infestation rates but results were not consistent. But this method is suitable for the maintenance of a laboratory culture of this insect.A special oviposition tube was developed for inducing oviposition on limited areas of muslin, and this permitted easy observation, collection and handling of eggs.It was found that oviposition tended to occur most frequently between 1900 and 2200 hr. and that the midges most commonly laid 200–285 eggs.Eggs developed normally and hatched after seventy-two hours when the muslin carrying them was kept on barely moist filter paper in petri dishes.Sixty-hour-old eggs could be stored for up to five days at 80 ± 2°C. with the percentage hatch decreasing gradually from the first to the fifth day. Low temperature affected development and hatching of thirty-six-hour-old eggs more severely, and hatching was completely inhibited if eggs of this age were exposed to this low temperature for more than two days. Hatching was normal when eggs were maintained at relative humidities of and above 88.8 per cent., but below this level some eggs collapsed as a result of desiccation. At relative humidities below 94.8 per cent., larval movement was initially limited and thereafter inhibited and the larvae were contracted. Such larvae resumed normal activity on immersion in water. These immobilised larvae, obtained by exposure of fully developed eggs to a relative humidity in the range 92.9–94.8 per cent., could be revived by immersion in water and used for infesting paddy plants.Fully developed eggs, freshly hatched larvae and larvae subjected to relative humidities in the range 92.9–94.8 per cent. and subsequently revived, were transferred to rica plants bt spraying, or by pipetting on the leaf at the ligules or by pipetting on to the soil at the bases of plants. All these mathods proved successful but pipetting on to the soil between rows of plants was the simplest and is to be preferred for controlled infestation of plants.A very high relative humidity and wet plant surfaces as obtained in the mist chamber used in these studies were essential for successful infestation of rice plants by the gall midge larvae.
The effects of crowding on the survival, rate of development, size, colour and fecundity ofDysdercus fasciatusSign. (Hem., Pyrrhocoridae) in the laboratory
Authors: Hodjat S. Hossein 
Published: July 2009

Experiments were conducted to ascertain whether the rearing density ofDysdercus fasciatusSign. affected its rate of development, colour, size, reproduction and general activity. The length of the nymphal and adult life decreased when more than 12 insects were reared per 200-cc. cage. Isolated virgin females and females that eopulated once lived longer than females each kept constantly with one male. Nymphal crowding in adults that were smaller than those reared in isolation and in an excess of males. Nympha derived from crowded parents became red at an earlier age than the progeny of one male and one female per cage. Crowding reduced feeundity when the density of nymphs or adults, either male or female, was increased.The pre-oviposition period and the time interval between successive egg-batches were greater for virgin than for mated females. Infertile eggs were the longest; females allowed to copulate once laid eggs intermediate in size between infertile ones and those laid by females each kept with a male. The number of eggs laid by females isolated throughout life with one male was found to be higher than the number laid by those that were crowded either in the nymphal stages or were crowded with males in the adult stage. When Dysdercu8 was crowded with one or two locusts the number of eggs laid and the number of egg-batches were considerably reduced; amputation or painting the antennae, which caused the Dysdercus to be less active, also reduced egg production but disturbance by mechanical shaking of the container had little effect. These findings are discussed in relation to the ' phases ' of locusts and other insects, and it is concluded that the effects of crowding on D. fasciatus do not completely parallel phase differences in locusts.