Occurrence Of Insects Research Articles

634A PB 527 INSECT PEST MANAGEMENT THROUGH A CABBAGE-INDIAN MUSTARD COMPANION PLANTING

Indian mustard (Brassica juncea) has been reported to be a preferred host for diamondhack moth (Plutella xylostellu) and other insect pests when interplanted with cabbage (Brasssica oleracea var. capitata). A cabbage-Indian mustard companion planting study was conducted to determine the seasonal occurrence of cabbage insects and the potential for using a trap-crop system to reduce insecticide applications to cabbage in West Texas. Three-row plots of cabbage 9 m long were transplanted with and without sequentially seeded borders of Indian mustard in three seasons. Harmful and beneficial insects were counted at roughly weekly intervals. Insecticides were applied when insect populations in individual plots reached predetermined thresholds. Indian mustard did not appear to be more attractive than cabbage to lepidopterous pests, but did preferentially attract hemipterans, particularly harlequin bugs (Margantia histrionica). The mustard trap crop eliminated two insecticide` applications in one trial by reducing harlequin bug pressure on the cabbage.

Assessment of insect occurrence in boreal forests based on satellite imagery and field measurements

Assessment of insect occurrence in boreal forests based on satellite imagery and field measurements

Green plants and plant-feeding insects

The natural limitations on insect herbivory are discussed with reference to factors affecting the occurrence of insects and those affecting the paiatability of plants. The specialised niches occupied by insects with different feeding methods are Illustrated and interactions between plant, herbivore and environmental stresses are discussed. A case study of Rumex spp. herbivores provides some suggestive starting points for practical project work.

Occurrence of bats in northernmost Sweden (65°N) and their feeding ecology in summer

The population density of the northern bat Eptesicus nilssoni at 65° N was about one‐fifth of that in southern Sweden (57° N). No other bat species was observed at 65° N. In one maternity colony, young northern bats were born in July and were flying by early August. The diet consisted mainly of small insects, predominantly dipterans, which were captured and eaten in the air. The bats maintained a nocturnal (22:00–02:30 h) foraging schedule in summer, partly reflecting the activity of insects, and spent about three hours away from the day roost each night. Owing to the short periods of darkness, the foraging flights usually started and ended in daylight. Habitat use reflected the occurrence of small insects near vegetation.

Occurrence of insects in coniferous roundwood imported to Sweden from France and Chile

Sweden requires all coniferous roundwood from countries outside Europe to have been debarked but makes no requirement for European wood. Six shipments of unbarked roundwood of Pinus pinaster from France and 14 shipments of debarked P. radiata logs from Chile were inspected in Sweden during 1988 and 1989. The imported wood from France yielded 92 insect species (90 Coleoptera and 2 Hymenoptera). Seventeen of these species do not occur in Sweden. All six consignments were thoroughly attacked by bark‐ and wood‐boring insects, representing 25 species. The logs from Chile had been well debarked; less than 1% of the inspected logs contained living insects. Nevertheless, a total of 49 insect species (46 Coleoptera, 1 Isoptera, 1 Hymenoptera and 1 Orthoptera) were found in the 14 shipments. Of these species 21 are not indigenous to Sweden.

Changes in Lake Trout Growth and Abundance after Introduction of Cisco into Lake Opeongo, Ontario

We examined changes in annual age-specific growth rates of 0–8-year-old lake trout Salvelinus namaycush in Lake Opeongo, Ontario, after the introduction of cisco Coregonus artedii into the lake in 1948. Growth rates of piscivorous lake trout (ages 3–8) initially increased as the occurrence of ciscoes increased, and then decreased as the abundance of piscivorous lake trout increased and the size of ciscoes eaten decreased. Growth of non-piscivorous 1- and 2-year-old lake trout decreased as the occurrence of insects decreased and the abundance of 1- and 2-yearold fake trout increased. Prey abundance, prey size, and intraspecific competition appeared to be major factors influencing growth rates. As ciscoes came to dominate the diet of adult lake trout, cannibalism by adults on younger lake trout decreased, as did the mortality suffered by young lake trout. The cisco introduction improved the existing sport fishery for lake trout by raising annual maximum sustainable yield from about 0.18 kg/hectare to about 0.48 kg/hectare; however, this increase was accompanied by heightened sensitivity of the population to over exploitation.

Aquatic insect emergence in two Great Lakes marshes

This study determined total number, biomass, taxa, and seasonal occurrence of adult aquatic insects emerging from four vegetation zones in one diked and one undiked freshwater coastal marsh on hypereutrophic lower Green Bay, Lake Michigan, USA during the summer of 1984. Floating box traps were placed in open water, sparse emergent, dense emergent, and wet meadow vegetation zones in each marsh. Insects were collected during 20 24-hour periods, each four days apart, from June 11 to August 26. Two-way ANOVA was used to test differences in number and biomass of insects between marshes and among vegetation zones. Polynomial regression was used to evaluate seasonal emergence patterns. More insects, insect biomass, and insect taxa were found in the diked marsh, especially during the first half of the sampling period. Damselflies were much more abundant in the diked marsh. Most insects and insect biomass were found in the sparse emergent vegetation zone of both marshes. The emerging insect community in the diked marsh appears enhanced by its separation from the hypereutrophic and turbid waters of lower Green Bay.

ChemInform Abstract: Neuropeptides ‐ Occurrence and Functions in Insects

Article de synthese sur les neuropeptides (de mammiferes et d'invertebres) identifies chez les insectes

Pressure cycles and the water economy of insects

Water exchange between insects and their environment via the vapour phase includes influx and efflux components. The pressure cycle theory postulates that insects (and some other arthropods) can regulate the relative rates of influx and efflux of water vapour by modulating hydrostatic pressures at a vapour-liquid interface by compressing or expanding a sealed, gas-filled cavity. Some such cavities, like the tracheal system, could be compressed by elevated pressure in all or part of the haemocoele. Others, perhaps including the muscular rectum of flea prepupae, could be compressed by intrinsic muscles. MaddrellInsect Physiol. 8, 199 (1971)) suggested a pressure cycle mechanism of this kind to account for rectal uptake of water vapour inThermobiabut did not find it compatible with quantitative information then available. Newer evidence conforms better with the proposed mechanism. Cyclical pressure changes are of widespread occurrence in insects and have sometimes been shown to depend on water status. Evidence is reviewed for the role of the tracheal system as an avenue for net exchange of water between the insect and its environment. Because water and respiratory gases share common pathways, most published findings fail to distinguish between the conventional view that the tracheal system has evolved as a site for distribution and exchange of respiratory gases and that any water exchange occurring in it is generally incidental and nonadaptive, and the theory proposed here. The pressure cycle theory offers a supplementary explanation not incompatible with evidence so far available. The relative importance of water economy and respiratory exchange in the functioning of compressible cavities such as the tracheal system remains to be explored. Some further implications of the pressure cycle theory are discussed. Consideration is given to the possible involvement of vapour-phase transport in the internal redistribution of water within the body. It is suggested that some insect wings may constitute internal vapour-liquid exchange sites, where water can move from the body fluids to the intratracheal gas. Ambient and body temperature must influence rates of vapour-liquid mass transfer. If elevated body temperature promotes evaporative discharge of the metabolic water burden that has been shown to accumulate during flight in some large insects, their minimum threshold thoracic temperature for sustained flight may relate to the maintenance of water balance. The role of water economy in the early evolution of insect wings is considered. Pressure cycles might help to maintain water balance in surface-breathing insects living in fresh and saline waters, but the turbulence of the surface of the open sea might prevent truly marine forms from using this mechanism.

Movements of adult aquatic insects along a Montana (USA) springbrook

The occurrence and movement patterns of adult insects along a forested springbrook near Flathead Lake, Montana, USA, were studied during three 15‐day periods from 19 June through 9 August 1985, using a two‐sided Malaise trap. Of the Plecoptera, numbers of males and gravid females ofMalenka flexura gravid females of Zapadafrigida and total numbers of Paraperla wilsoni were significantly higher for downstream‐flying adults during one to three periods. Of the Trichoptera, numbers of males of Anagepetus debilis were significantly higher for upstream‐flying adults during one period, and males of Lepidostoma cascadense and gravid females of L. spicata were significantly higher for downstream‐flying adults during another period. In none of the 26 species examined in these three orders did females show a statistically significant pattern of upstream flight.

The occurrence and diversity of Coal Measure insects

Insects are generally considered to be rare in the Upper Carboniferous Coal Measures. However, recent work in the Westphalian D of SW England suggests that many have been overlooked in the past. This is because wings, which are the most characteristic insect fossils, may be mistaken for detached ‘fern’ pinnules, which are much more common. The resemblance may be functional convergence rather than leaf-mimicry. The earliest members of the class Insecta in the strict sense occur in the Upper Carboniferous. Eleven major divisions or orders are represented in the Coal Measures of which only four are still living. Primitively wingless insects (Archaeognatha) are present, relatives of familiar living insects such as the silverfish. There are numerous winged insects, some of which could fold their wings (Neoptera) and others which could not (Palaeoptera). Palaeopterous insects were more diverse than today. They include three extinct orders (Palaeodictyoptera, Megasecoptera, Diaphanopterodea) which were probably plant suckers like present clay bugs. Other extinct palaeopterous insects (order Protodonata) were probably aerial predators like modern dragonflies, and included some of the largest insects of all time (‘giant dragonflies’). By far the most common neopterous insects were cockroaches (Blattodea) which outnumber all other insects in the Upper Carboniferous. This abundance is perhaps less surprising when one considers the general picture of the coal forests as warm, humid, and rich in organic matter. Another important neopterous group was the extinct order Protorthoptera, which is probably related only in part to extant Orthoptera (grasshoppers, crickets and locusts). There is no evidence at this time of higher insects such as flies, fleas, beetles, moths and butterflies, ants, bees and wasps.

INTRODUCTION

In general, the aquatic insects of freshwater wetlands have been inadequately studied despite their apparent importance in wetland habitats, especially in energy and nutrient transfer. The Biological Survey of Canada (Terrestrial Arthropods) recognized the deficiencies in knowledge of taxonomy and ecology of insect species in wetland habitats and sponsored a "Conference on the aquatic insects of peatlands and marshes" in St. Andrews, New Brunswick, on 3 October, 1984. The Conference summarized current knowledge on the systematics and ecology of aquatic insects of Canadian peatlands and marshes, the wetland habitats chosen for emphasis, and sought to identify needs for research on the structure and dynamics of aquatic insect faunas in these habitats. The proceedings of the Conference are published here. The first two papers provide background information on the habitats under consideration and the interactions among invertebrates and vertebrates in these habitats. A second group of papers considers features of the Hydracarina, Ephemeroptera, Odonata, Hemiptera, Trichoptera, Coleoptera, and Diptera in peatlands and marshes. A final paper summarizes data on the occurrence of aquatic insects in bogs, fens, and marshes, addresses broader questions related to the nature of the insect fauna, and identifies needs for further research. By making accessible systematic and ecological information on aquatic insects of Canadian peatlands and marshes, the proceedings should support and encourage further work in these habitats.

AQUATIC INSECTS OF PEATLANDS AND MARSHES IN CANADA: INTRODUCTION

AbstractIn general, the aquatic insects of freshwater wetlands have been inadequately studied despite their apparent importance in wetland habitats, especially in energy and nutrient transfer. The Biological Survey of Canada (Terrestrial Arthropods) recognized the deficiencies in knowledge of taxonomy and ecology of insect species in wetland habitats and sponsored a "Conference on the aquatic insects of peatlands and marshes" in St. Andrews, New Brunswick, on 3 October, 1984. The Conference summarized current knowledge on the systematics and ecology of aquatic insects of Canadian peatlands and marshes, the wetland habitats chosen for emphasis, and sought to identify needs for research on the structure and dynamics of aquatic insect faunas in these habitats. The proceedings of the Conference are published here. The first two papers provide background information on the habitats under consideration and the interactions among invertebrates and vertebrates in these habitats. A second group of papers considers features of the Hydracarina, Ephemeroptera, Odonata, Hemiptera, Trichoptera, Coleoptera, and Diptera in peatlands and marshes. A final paper summarizes data on the occurrence of aquatic insects in bogs, fens, and marshes, addresses broader questions related to the nature of the insect fauna, and identifies needs for further research. By making accessible systematic and ecological information on aquatic insects of Canadian peatlands and marshes, the proceedings should support and encourage further work in these habitats.

Occurrence of new diseases and insects in Kanto-Tosan district

Occurrence of new diseases and insects in Kanto-Tosan district

Modeling Insect Development Rates: a Literature Review and Application of a Biophysical Model

The importance of predicting the seasonal occurrence of insects has led to the formulation of many mathematical models that describe development rates as a function of temperature. Yet many of the widely used models do not provide acceptable results for predicting development times. After a careful review of the literature, we believe the biophysical model of Sharpe and DeMichele (1977; J. Theor. Biol. 64: 649–670) is the most suitable for this purpose. This model provides an excellent description of development rates over a full range of temperatures, and can be modified easily to describe rates over a portion of that range. Herein we review the literature on modeling insect development rates, describe the Sharpe and DeMichele model, and present easy instructions for its use. A computer program, assembled from the Statistical Analysis System (SAS) Library, determines the correct number of parameters to be used in the model for a given data set, selects starting values of these parameters for nonlinear regression, and computes least-square estimates of the parameters by using Marquardt techniques.

Emergence of Stoneflies (Plecoptera) from South Duck River and Cowan Creek in the Duck Mountain Region, Manitoba

Eight species of Plecoptera were collected in emergence traps located along two streams in the Duck Mountain region of W-central Manitoba. Imagines were collected throughout the mid-May to mid-September 1980 sampling period with most emergence occurring in spring and autumn. Over 95% of the emergence consisted of Hastaperla brevis and Malenka californica. Peak emergence of H. brevis occurred in late spring. Malenka californica had two different emergence patterns; at two stations, one in each stream, emergence began in midto late June and continued, intermittently, to the end of the sampling period with lowest emergence occurring during July and August. At all other stations, emergence was mainly restricted to late August and September. Sex ratios in each species were either approximately equal or there were generally more or only females collected. In species where large numbers of animals emerged, emergence of sexes overlapped. These are the first records of M. californica and Suwallia pallidula for the Province of Manitoba. INTRODUCTION Studies of insect emergence are valuable in providing information on diversity and seasonal occurrence of aquatic insects. Systematic studies of seasonal emergence of Plecoptera in Canada have been conducted in Quebec (Harper and Magnin, 1969; Harper and Pilon, 1970), Ontario (Sprules, 1947; Harper, 1973a, b; Harper and Hynes, 1972), Saskatchewan (Dosdall and Lehmkuhl, 1979) and Alberta (Radford and Hartland-Rowe, 1971; Donald and Anderson, 1977). No emergence studies of Plecoptera in Manitoba have been published. This paper describes an investigation of species composition, emergence periods, spatial distribution and abundance of adult Plecoptera, based on emergence data obtained over most of the open-water season, from two small, permanent streams in the Duck Mountain Region of W-central Manitoba. METHODS South Duck River (SD) and Cowan Creek (C), originate on the Manitoba Escarpment and flow into Lake Winnipegosis. The streams are spring-fed and are ice-covered in winter. Emergence trap stations were located on the Manitoba Escarpment (52048'N, 100040'W). Stations SD1, C1, C2 and C3 were located in areas with mixed forest (spruce, aspen, birch); the remaining stations were surrounded by forested and agricultural lands. Stream habitats ranged from fast-flowing riffle areas to siltbottomed pools. General features, including substrate types, of areas where emergence trap stations were located are listed in Table 1. Two 1 m2 emergence traps (Flannagan, 1978) were set at each station except at C4 where there was only one. One trap at each station was located over a riffle and the other over a pool, except at SD3 which had no pool areas and where both traps were located over riffle areas. Each trap was cleared every 2nd day and specimens were preserved in 70% alcohol. Sampling began 11 May 1980 and continued until 19 September 1980, except for Cl and C2 where sampling began on 21 May 1980. The

Numerical relationships of the Solidago altissima stem gall insect-parasitoid guild food chain.

The field site conditions (soil pH, soil moisture, soil nutrient availability, etc.) and abundances of Solidago altissima (often included in S. canadensis sensu lato), three S. altissima specific stem gall formers, and the parasitepredator guilds for two of the three gall insects were investigated. It was found that S. altissima is tolerant of a wide range of site conditions. Herbivore (stem gall insects) occurrences were positively correlated with plant occurrence, in a linear fashion. However, there was no disproportionate increase in stem gall insect densities with plant density as might be predicted by the resource concentration hypothesis. Parasitoid guilds were exploiting stem gall insect populations over a wide range of occurrence, but were under-utilizing fields of higher herbivore occurrences. Path analysis showed a high degree of predictability in the causal models, with all but 14% of the ball gall parasitoid guild and all but 43% of the elliptical gall parasitoid guild occurrences explained by the direct influences of stem gall insect occurrence and the indirect influences of goldenrod occurrence and site conditions. The numerical relations of this three trophic level system suggest a well-integrated and well-controlled food chain.

Some aquatic insects as water quality indicators in the river Khan

This paper deals with the evaluation of water pollution in the river Khan, by the study of the insect community structure. These studies show that aquatic insects can serve as useful indicators of water quality in the river. The occurrence of insects in various stretches of the river Khan has been correlated with certain physico‐chemical conditions of the river water.

Long-chain polyunsaturated fatty acids: Patterns of occurrence in insects

Most published analyses of the fatty acid compositions of insect tissue do not record long-chain polyunsaturated fatty acids beyond C18:3. When this is set against recent discoveries of important nutritional and prostaglandinogenic roles for arachidonic and other long-chain polyunsaturates in several insects of diverse taxa, the issue of a possible general occurrence of such material in insects assumes compelling interest. We used gas chromatographic methods to investigate the presence of fatty acids of more than 18 carbon atoms in lipid extracts from whole-animal and specific tissue preparations, and in particular fractions of lipid extracts. Results indicate that such compounds generally occur as a low proportion of the total fatty acids in whole-animal extracts and in neutral acyl fractions. Larger numbers and higher proportions of long-chain fatty acids were detected in extracts of certain tissues and in the phospholipid fractions of whole animal extracts than were found in the unfractionated whole-animal extracts. These findings show that long-chain polyunsaturated fatty acids are a regular component of the tissues of the insects examined and, in the light of their known nutritional, prostaglandinogenic and presumed structural roles are of considerable biological significance.

Seasonal fluctuations in the diet composition ofRhinopoma hardwickei in the Rajasthan desert

The small mouse-tailed bat,Rhinopoma hardwickei, collected from various districts of Rajasthan, is primarily an insectivorous species. Orthoptera, Dictyoptera, Lepidoptera, Hymenoptera, Coleoptera and Diptera are preferred in all main four seasons in varying amounts, while Isoptera are consumed in all but the winter season. Occurrence of ground dwelling insects, caterpillars, spiders and water beetles in the stomachs of bats have been discussed in the light of behavioural adaptations of this species. Presence of fur of same bat species in stomachs coincides with its breeding season. Presence of various polyphagous insect pest species of crops in feeding menu of bats shows that this species plays an important role in biological management of harmful insects.