ABSTRACT BOOK I XXI-International Congress of Entomology, Brazil, August 20-26, 2000

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1 [0797] PROBLEMS AND STATUS OF TAXONOMIC RELATIONSHIPS AMONG CEPHIDAE M. Ivie ABSTRACT NOT RECEIVED [0799] ASPECTS OF THE ECOLOGY OF THE WHEAT STEM SAWFLY (HYMENOPTERA: CEPHIDAE) IN NORTH AMERICA D.K. Weaver 1, W. L. Morrill 1, R. J. Bartelt 2, A. A. Coss? 2, M. J. D. Grieshop 1 & G. D. Johnson 1, 1 Dept. of Entomology, Montana State Univ., Bozeman, MT USA, E- mail weaver@montana.edu; 2 National Center for Agricultural Utilization Research, USDA-ARS, 1815 N. University Ave., Peoria, IL USA. Cephus cinctus, the wheat stem sawfly, is a major pest of wheat and other cereals the northern Great Plains of North America. It occurs throughout much of North America, but in regions away from the northern Great Plains populations are confined to feral grasses. It is likely that the host plants in the crop and grassland habitats differ in their developmental phenology, thus resulting in cereal cropland being an unused host reservoir in regions away from the areas of economic loss. Recently, Montana populations of this insect have moved into the earlier maturing winter wheat crop from spring wheat, indicating the pest is adapting to cultural practices. The wheat stem sawfly has an obligatory diapause, and it is suspected that geographically diverse populations in North America have differing requirements to break prepupal diapause. After diapause is broken, metamorphosis is completed, and adult males emerge several days before females. Mature females will lay unfertilized eggs, resulting in male offspring, if they do not mate. The mating system of this insect is quite complicated. In cereal crop systems, abundant newly emerged individuals will occasionally mate immediately in the fallow crop residue, but the majority of the mating occurs at the border of the current year s crop. Here, small groups of males form spatially discreet leks that serve to influence receptivity and mating with nearby females perched on vegetation. Lek events are short-lived and recurring, but appear to be triggered by a combination of favorable temperature and bright insolation. Males in a lek area do not appear to relocate, but mated females appear to move into the standing crop to oviposit. This lek-driven mating system utilizes a powerful, nearinstantaneous release of pheromone compounds to facilitate mating. A number of compounds have been identified as having a behavioral and sensory role in this pheromone blend. The lek system appears unusual in a large, continuous acreage of cultivated suitable hosts, but may have developed to facilitate reproduction in relatively arid ancestral grasslands where bunchgrasses and small patches of suitable hosts predominated. Index terms: Cephus cinctus, pheromone, chemical ecology, lek [0798] DO HOST-PLANT INTERACTIONS AND SUSCEPTIBILITY TO SOIL CULTIVATION DETERMINE THE ABUNDANCE OF GRAMINIVOROUS SAWFLIES ON BRITISH FARMLAND? A.M. Barker & C.J.M. Reynolds, The Game Conservancy Trust, Burgate Manor, Fordingbridge, Hants, SP6 1EF, U.K. abarker@game-conservancy.org.uk Relatively little is known about the graminivorous sawflies of the two genera Dolerus and Pachynematus, which feed on cereals and grasses in farmland habitats. Dolerus species are univoltine with spring flying adults and larvae present in the field from May to July; Pachynematus species are bivoltine with spring and summer generations. Both overwinter as pupae underground. In Britain these sawflies are not economic pests but they have an important role in the wider ecology of agricultural ecosystems as important sources of food for birds. In a four-year farm survey, we found that larvae of these two sawfly genera were over six times more abundant in fields of sown perennial rye-grass Lolium perenne than in winter wheat and spring barley crops or long-established grazing pastures. To investigate the factors behind this distribution, we conducted oviposition and rearing trials and experimentally investigated the effect of ploughing on overwintering survival. We found that the three most common Dolerus species and one of the two common Pachynematus species generally preferred perennial rye-grass to winter wheat (Triticum aestivum) and spring barley (Hordeum vulgare) as oviposition hosts. Growth and survival of larvae of five Dolerus species and one out of two Pachynematus species tested were also significantly higher on rye-grass than on winter wheat or spring barley. Subsequent trials have identified a range of grasses that make more suitable hosts than either cereal. Differences were sufficiently marked to have had a strong influence on the distribution of larvae between crops in the field. In addition, in trials in which we used emergence traps on cultivated and uncultivated areas of the same fields we found that in some years the soil disturbance caused up to 50% extra overwintering mortality, although the extent of this mortality varied from year to year, possibly as a result of variation in the severity of winter weather. This mortality will reinforce the effects of host-plant requirements in leading to decreasing abundance in ploughed cereal habitats. Shifts in patterns of crop rotation towards intensive cereal production with yearly cultivation and also more efficient farming with fewer wildlife-friendly grassy field boundaries may account for recorded decreases in graminivorous sawfly abundance on British farmland. Index terms: Dolerus, Pachynematus, winter wheat, spring barley, perennial rye-grass [0800] ACOUSTIC DETECTION AND MONITORING OF CEPHUS CINCTUS SAWFLY LARVAE IN WHEAT STEMS R. W. Mankin 1 & D. K. Weaver 2, 1 USDA-ARS-CMAVE, P. O. Box 14565, Gainesville, FL 32604, USA, rmankin@gainesville.usda.ufl.edu; 2 Dept. of Entomology, Montana State Univ., P.O. Box , Bozeman, MT , USA. The behavior of Cephus cinctus Norton larvae in wheat is difficult to study because they are hidden from view inside the stems. We tested the feasibility of using acoustic techniques to nondestructively identify infested stems and monitor larval activity. Adult females were allowed to oviposit in small pots of wheat. After three weeks, a small accelerometer was clamped to the base of each stem and sounds were recorded for ~3 minutes. Infested stems and uninfested stems in motion produced short clicks ~0.5 msec in duration. The clicks could be detected in the moderate background noise of a research laboratory without using an insulated room or anechoic chamber. No clicks were recorded from stationary, uninfested stems. After recording, the stems were cut and the locations and weights of any larvae were noted. The signals were analyzed using custom-written digital signal processing software. Methods were developed to distinguish larval movement and feeding activity from background noises. In the initial study, we identified putative larval sounds from 17 of the stems tested. All were infested with larvae (mean weight = / mg). The mean rate of clicks produced by larvae in the infested stems was / clicks per minute. Our experience in the initial study led to development of an improved device for clamping the accelerometer to the wheat stem. The use of nondestructive techniques will enable the future monitoring of long-term activity patterns. Index terms: sound, behavior, activity pattern. 202

2 [0801] IMPACT OF CULTURAL PRACTICES ON POPULATIONS OF THE WHEAT STEM SAWFLY (HYMENOPTERA: CEPHIDAE) AND ITS ASSOCIATED PARASITOIDS W. L. Morrill, S. E. Sing, J. B. Runyon & D. K. Weaver, Dept. of Entomology, Montana State Univ., Bozeman, MT USA The wheat stem sawfly, Cephus cinctus, is an important pest the northern Great Plains of North America. Records indicate that sawflies first occurred in native prairie grasses and were held in check by parasitoids. Wheat was infested when tillage began about a century ago. Many farmers established narrow strip fields to minimize soil erosion and also used alternate-year, or summer fallow to conserve moisture from 2 years for one crop. These practices affect pest insect and weed populations. Cephus cinctus larvae overwinter in lower stem sections, or stubs. Wasps emerge in June and disperse to standing crops. Although several eggs may be laid in each stem, only one larva survives to maturity due to cannibalism. Larvae complete their development while enclosed within the stems. Infested stems yield less, and usually break or lodge, before harvest. Insecticide application and other traditional control practices are not effective, therefore a biological control program should be developed. Bracon cephi and B. lissogaster (Hymenoptera: Braconidae) are larval parasitoids that commonly attack C. cinctus in Montana. Levels of parasitism in fields are affected by wheat production practices, and range 5 90%. We compared sawfly larval population densities and percent larval parasitism in different winter wheat production systems. The variables were field size (narrow strip fields vs larger block fields) and weed control methodology (herbicide vs tillage). Data indicate that sawfly damage is higher in field borders, therefore overall losses decrease as field size increase. Intensive spring soil tillage of fallow fields suppresses parasitoid populations. In another study, we intensively sampled spring wheat fields to document the spatial pattern and abundance of wheat, wild oat (Avena fatua), sawflies, and parasitoids. Sawfly wasps are more prevalent at the field edges, but larval infestations extend across fields. Wild oat influences the patchiness of larval infestation in wheat. Sawfly wasps readily oviposit in wild oat, but the resulting larvae do not survive. Index terms: Cephus cinctus, Bracon, IPM, biological control, Avena fatua [0803] BIOLOGICAL CONTROL OF WHEAT STEM SAWFLIES: PAST AND FUTURE T. G. Shanower 1, 1 USDA-Agricultural Research Service, 1500 N. Central Ave., Sidney, MT 59270, USA; tshanowe@sidney.ars.usda.gov Several species of grass-feeding stem sawflies (Hymenoptera: Cephidae) are important pests of wheat and other grain crops in the northern hemisphere. At least six species have been reported as pests including Cephus fumipennis in China, C. cultratus in central Asia, and C. pygmaeus and Trachelus tabidus in the Mediterranean region. The latter two species are also widespread in Europe and were introduced into eastern North America more than 100 years ago. A third species, C. cinctus, attacks wheat in western North America though its origin is uncertain. The biology of these species is similar. Females oviposit in cereal or grass stems and larvae feed within the stem. The larva moves to the base of the plant as it matures and cut a groove around the inside of the stem. The lumen of the stem is plugged below the groove, forming a chamber for the diapausing larva during the winter or dry season. The weakened stem breaks at the groove leaving a stub. Increased temperatures, moisture and/or photoperiod terminate diapause. Pupation occurs within the stub and adults emerge several weeks later. Stem feeding by sawfly larvae reduce grain weight up to 30%. Fallen, unharvested grain is an additional and unquantified loss. Yield losses of up to 35% have been reported from several countries. Annual losses due to C. cinctus in North America are estimated at approximately US$100 million. Biological control efforts were first initiated against C. cinctus. Three parasitoids were released in western Canada from : two were imported from England and the third came from the eastern US. A second biological control attempt was undertaken in the western US from , using parasitoids imported from France. No exotic natural enemies have been established against C. cinctus. Biological control efforts against C. pygmaeus were carried out in the US and in Canada. Three species were imported from Europe but only Collyria coxator (Hymenoptera: Ichneumonidae) has been established in North America. It appears to play an important role in regulating C. pygmaeus populations, parasitizing up to 80% of C. pygmaeus larvae. The USDA-ARS has initiated a project to find and import effective, new biological control agents for C. cinctus in the western US. Analysis of the failed attempts against this species, and the successful effort against C. pygmaeus, provide insight and important lessons for this new program. This paper reviews previous biological control efforts against wheat stem sawflies, discusses possible reasons for the earlier failures, and outlines the approach and progress of the new project. Key words: Cephus spp., Collyria spp., parasitoids [0802] SAWFLIES IN EUROPE: DAMAGE AND CONTROL STRATEGIES A. Harris ABSTRACT NOT RECEIVED [0804] FOREIGN EXPLORATION FOR SAWFLY NATURAL ENEMIES K. Hoelmer, USDA-ARS, European Biological Control Laboratory, Campus International de Baillarguet,CS Montferrier-sur-Lez, St. Gély du Fesc Cedex, France, E- mail khoelmer@wanadoo.fr. Sawflies (Hymenoptera: Cephidae: Cephini) which feed and develop within the stems of small grain crops are widespread throughout the the northern hemisphere, particularly in the Palearctic region. Wheat is the primary crop impacted, but these sawflies also attack rye, barley and timothy, as well as various native, non-crop grasses. Cephid species causing significant damage to crops occur in North America, Europe, Asia and north Africa. However, relatively little is known regarding their ecology in wild grass hosts, including the occurrence and impact of natural enemies. Following the successful introduction and establishment of European parasitoids against Cephus pygmaeus in North America, several unsuccessful attempts were made during the early to mid-twentieth century to establish new parasitoids, also originating from Europe, against Cephus cinctus in North America. The failures were attributed to a lack of adaptation to C. cinctus or to the lack of proper synchronization with suitable host stages. Further collections and introductions were not pursued at that time. However, taxonomic uncertainty exists regarding the identity and relationship of various species of Cephus. Important natural enemy taxa are also in need of revision. Further field collections and biological studies are warranted, especially for species in central and eastern Asia for which information is particularly sparse. Such collections would provide new study material for taxonomic revisions, and possibly new populations and/or species of natural enemies for biological control evaluations. Thus, new opportunities exist for the discovery and collection of better-adapted parasitoid populations in regions with climates that are very similar to those of the desired areas of introduction. Greater success in evaluations and releases may also result from faster delivery and better handling of overseas shipments, and from improved knowledge of natural enemy biology, behavior, and ecology. Index terms: Cephus, Trachelus, parasitoids. 203

3 [0805] CONDITIONAL MUTUALISMS IN ANT-PLANT-HERBIVORES INTERACTION IN TROPICAL SAVANNA K. Del-Claro, Univ. Fed. Uberlândia, InBio, CP593, Cep , Uberlândia, MG, Brazil. The outcomes of mutualistic interactions are dependent upon the ecological settings in which they occur. In this directions we will show results of two studies conduced in Brazilian cerrados. Controlled ant-exclusion experiments in a system involving an extrafloral bearing Malpighiaceae, Peixotoa tomentosa, revealed that herbivory and fruit production are dependent on ant associated species behavior. Also the interaction between herbivore-ant behavior and herbivore-ant-plant morphologies can change the meaning of each relationship. In the association between the honeydew-producing membracid Guayaquila xiphias and its ants attendants, two years of controlled ant-exclusion experiments showed that ant effects on treehopper survival and fecundity were conditioned by time, and varied with shifts in the abundance of natural enemies. In both studies the results also revealed that plants and herbivores are positively or negatively affected depending on ant presence and species. Index terms: Guayaquila xiphias, Camponotus, Thysanoptera, Malpighiaceae, Araliaceae. [0807] ANT-WHITEFLY INTERACTION IN A NEOTROPICAL FOREST: ANT ATTENDANCE REDUCES FUNGAL AND PARASITOID ATTACK J. M. Queiroz & P. S. Oliveira, Departamento de Zoologia, Universidade Estadual de Campinas, C.P. 6109, Campinas SP, Brasil. jqueiroz@obelix.unicamp.br. Sap-feeding whiteflies (Aleyrodidae) have increasingly attracted the attention of applied entomologists due to the severe damage that these homopteran insects may cause to economically important crop plants. Whitefly damage to plant results mainly from colonization by sooty mold encouraged by honeydew build-up, which markedly depreciates the commercial value of plant-derived food products. Continuous collection of honeydew by tending ants can confer a range of benefits to homopterans such as aphids, scales, and treehoppers. Surprisingly, however, despite the widespread ocurrence of anthomopteran associations in temperate and tropical regions, there is no experimental study on ant-whitefly interaction. We investigated the interaction between the honeydewproducing whitefly Aleurothrixus aepim (Hom: Aleyrodidae) and tending ants on shrubs of Croton floribundus in a forest reserve in SE Brazil. Ovipositions of A. aepim were randomly divided in two experimental groups: control (ants present) and treatment (ants excluded). Adults emerged in significantly greater numbers from control than from treatment aggregations, the latter being heavily attacked by fungi due to accumulation of honeydew. Decimation by fungi due to honeydew build-up was 3 times more frequent at ant-excluded than at ant-tended groups. Control aggregations with low levels of ant attendance produced significantly fewer adults than those more frequently tended by ants. Parasitoid wasps were more frequent on ant-excluded than on control whitefly aggregations. This is the first demonstration of an ant-derived benefit to honeydewproducing whiteflies. Given that aleyrodid honeydew causes severe damage to several crop plants in tropical and temperate areas, our results suggest that the honeydew-gathering activity by tending ants can be relevant for the management of agroecosystems. Index terms: Aleurothrixus aepim, Aleyrodidae, Homoptera, honeydew, mutualism [0806] ONTOGENY FO DEFENSE IN THE TEMPERATE ANT-PLANT SYSTEM INVOLVING CHAMAECRISTA FASCICULATA R. J. Marquis ABSTRACT NOT RECEIVED [0808] CONSEQUENCES OF MAMMALIAN HERBIVORY ON MULTITHROPHIC INTERACTIONS: INSECTS, PLANTS AND NATURAL ENEMIES R. Dirzo ABSTRACT NOT RECEIVED 204

4 [0809] PATTERNS OF SPECIALIZATION AMONG LEPIDOPTERAN HERBIVORES OF INGA (FABACEAE: MIMOSOIDEAE) AND THEIR PARASITOIDS S. Koptur, Dept. of Biological Sciences, Florida International Univ., Miami, FL 33199, USA, [0811] MOVEMENT OF ORGANISMS IN THE BIOSPHERE: A PERSPECTIVE ON SATIAL AND TEMPORAL SCALES S.H. Gage ABSTRACT NOT RECEIVED Lepidopteran eggs and caterpillars encountered on five common species of montane Costa Rican Inga over a two-year period were reared for identification and parasitization information. Fifty species in sixteen families of Lepidoptera were reared: eleven spp. of microleps (Oecophoridae, Gelechiidae, Torticidae); 32 spp. of moths in eleven families (Limacodidae, Megalopygidae, Pyralidae, Pterophoridae, Saturniidae, Geometridae, Eupterotidae, Noctuidae, Notodontidae, Arctiidae, Ctenuchidae); 2 skipper spp. (Hesperiidae) and 5 butterfly spp. (Pieridae). All Inga spp. have extrafloral nectaries that serve to attract both ants (more common at lower elevations) and parasitoids (more frequent at higher elevations where ants are scarce). Several parasitoid species reared from herbivores were also collected at nectaries. Egg parasites included species of Cecidomyiidae, Encyrtidae, and Scelionidae. Many caterpillars were killed by parasitoids, primarily flies (Tachinidae) and wasps (Braconidae, Eulophidae, Ichneumonidae), though some were consumed by entomophagous fungi. Eight of the herbivore species occurred on most of the Inga spp., while most were restricted to one or two species. Herbivore species that were found on more than two species of Inga were parasitized more frequently than those species found on only one hostplant species. Index terms: Pieridae, Megalopygidae, Hesperiidae, Braconidae, Tachinidae. [0810] A FRAMEWORK FOR INSECT MIGRATION STUDIES AND SOME RECENT ADVANCES H. Dingle, Dept of Entomology, Univ. of California, Davis, One Shields Ave., Davis, CA 95616, USA. rdhdingle@ucdavis.edu. Following Drake et al. (1995), we can think of a migration system as consisting of an arena in which migration takes place, a population trajectory, and a behavioral syndrome based in the genes and molded by natural selection. Habitat duration in the arena influences the frequency and occurrence of migration, and this is often determined by climate. A clear example occurs in Australian butterflies where climate variables such as soil moisture levels profoundly affect the proportion of migrants among butterfly regional faunas. Population trajectories are often wind guided, but in robust flyers like butterflies may be under the control of the individual insect and involve well-developed orientation mechanisms. Examples of orientation will be presented for both Australian and North American butterflies. Migration syndromes involve not only flight itself but also a variety of correlated traits from life history characters to flight muscle enzyme properties. These are revealed by studies of migratory and flight polymorphisms, and I shall provide examples from rapidly evolving species of seed bug (Hemiptera). Finally, I shall demonstrate that the syndromes are based in the genes. Throughout I shall stress important gaps in our knowledge and suggest some directions future studies might take. Index terms: Flight, butterflies, Hemiptera, polymorphisms, climate [0812] SPATIAL ANALYSIS OF PEST MOTH POPULATIONS IN THE UK AND EUROPE I. P. Woiwood ABSTRATC NOT RECEIVED 205

5 [0813] INSECT MIGRATION AND POPULATION PROCESSES IN INLAND AUSTRALIA OBSERVED WITH MONITORING RADARS V.A. Drake & H.K. Wang, School of Physics, University College, The University of New South Wales, Australian Defence Force Academy, Canberra, ACT 2600, Australia. In the semiarid environments of inland Australia, erratic rainfall leads to highly variable and essentially unpredictable spatial and temporal patterns of vegetation growth. These regions host a number of species of migratory insects that are well adapted to exploiting ephemeral vegetation flushes, and which can develop very large populations when conditions remain favourable for several generations. Some of these species are pests and cause major economic impacts when population growth is followed by migration into adjoining or distant dryland and irrigated cropping areas. A current study of the movements of these populations aims to relate them to the changing distribution of resources, with the twin objectives of developing understanding of how the species' migratory adaptations function and of improving pest-forecasting capabilities. Data acquisition for the study is centred around a pair of automatic monitoring radars that quantify the intensity, direction, speed, and altitude of nocturnal migration at two locations within the study area. The direct observations of insect movement that these radars provide are supplemented by satellite data on vegetation state and rain-producing clouds, and by a limited program of surveys (of both hosts and pests) and light trapping. Wind-borne transport opportunities are identified from regional meteorological analyses, and the various observations are integrated within a Geographic Information System. The potential of this suite of observing and analysis techniques is illustrated with data on spring movements of Helicoverpa punctigera and other moths, and summer movements of Australian plague locusts Chortoicetes terminifera. Index terms: Chortoicetes, Helicoverpa, moth, locust, forecast. [0815] SHORT-RANGE MIGRATION BY BEMISIA WHITEFLIES D. Byme ABSTRACT NOT RECEIVED [0814] INVESTIGATING OPTIMAL MIGRATION STRATEGIES IN BUTTERFLIES: THE USE OF LOCAL AND CELESTIAL CUES TO ADJUST COURSE AND FLIGHT SPEED E. G. Oliveira 1, R. B. Srygley 2 & R. Dudley 3, 1 Depto. Biologia Geral, Inst. Ciências Biológicas, Univ. Federal de Minas Gerais, , Belo Horizonte, MG, Brazil, E- mail evandro@mono.icb.ufmg.br; 2 Dept. Zoology, South Parks Road, Univ. of Oxford, Oxford OX1 3PS; 3 Section of Integrative Biology, Univ. of Texas, Austin, TX, 78712, U.S.A. [0816] THE RELATION OF ATMOSPHERIC FACTORS AND THE DISTRIBUITION OF APHIDS AND OTHER SMALL INSECTS IN THE AIR M. E. Irwin ABSTRACT NOT RECEIVED Butterfly migrations occur worldwide and are particularly common in the tropics, where distribution of rainfall appears to underlie both the phenology and direction of movements. In such cases, migration may require butterflies to discriminate favorable meteorological conditions in order to initiate flight and to be equipped with orientation and navigation mechanisms to reach particular geographical destinations. In addition, migration may involve high energetic expenditure, and butterflies may be required to adopt optimal or more efficient migratory strategies in order to minimize costs. Over the last several years, we have investigated these questions on a multi-species migration system in Panama and Colombia. Results from clock-shift experiments performed with two butterfly species (Aphrissa statira and Phoebis argante) supported the hypothesis that a time-compensated sun compass is used for migratory orientation. Vector analysis of butterfly airspeed, track direction, wind speed, and wind direction to estimate butterfly heading and drift showed that butterflies (A. statira, Phoebis argante, and Marpesia chiron) change their headings to compensate for crosswind drift. This result suggests use of a sun compass in coordination with directional information obtained from local landmarks. Butterflies were less likely to compensate for crosswind drift when local landmarks were absent. In contrast, no evidence for wind drift compensation was found in the day-flying uraniid moth Urania fulgens. Also as predicted from optimal migration theory, butterflies (P. sennae) adjusted their airspeed according to wind direction, flying at a lower speed with tailwinds. However, the two sexes seem to adopt different migratory strategies, as only females exhibited this last behavior. Males may minimize migration time to destination in order to increase their chances to fertilize newly emerging females. Finally, as suggested by aerodynamic theory, flight speed of U. fulgens decreased as endogenous energy reserves were gradually depleted. Together, these findings support the general notion that insect migration comprises specialized behavioral and physiological processes, and that insects approximate an optimal migratory strategy. Research on behavioral mechanisms may provide the basis for understanding the adaptive significance of butterfly migrations and for planning their conservation. Index terms: Lepidoptera, migration, sun-compass, airspeed, optimal behavior 206

6 [0817] RAPID EVOLUTION OF FLIGHT POTENTIAL IN LEPIDOPTERA K. Wilson 1, J.K. Hill 2,3, C.D. Thomas 2 & O.T. Lewis 2, 1 Institute of Biological Sciences, University of Stirling, Stirling FK9 4LA, UK, kw2@stir.ac.uk; 2 Centre for Biodiversity & Conservation, School of Biology, University of Leeds, Leeds LS2 9JT, UK; 3 Environmental Research Centre, Department of Biological Sciences, University of Durham, Durham DH1 3LE, UK. [0819] MODELLING OF INSECT MOVEMENT AND RELATED BEHAVIOUR IN 3D SPACE: NEW TOOLS, OLD QUESTIONS, BETTER SOLUTIONS? J. Hanan ABSTRACT NOT RECEIVED Many studies have investigated changes in flight-related traits in insects over evolutionary time (e.g reduced dispersal on true oceanic islands, evolution of migration syndromes in heterogeneous habitats). Here we produce evidence of rapid evolutionary changes in flight traits in ecological time. We present data showing evolutionary changes in flight-related traits in Lepidoptera in response to changes in availability of breeding habitat (due to rainfall, habitat fragmentation, climate change etc) occurring on an ecological time scale. We discuss implications of these rapid changes for insects persisting in modern landscapes, and for their ability to track newly-available habitat. Index terms: Spodoptera exempta, Pararge aegeria, Hesperia comma, phenotypic plasticity. [0818] MOVEMENT OF APHID PARASITOIDS OVER DIFFERENT SPATIAL [0820] INTERSPECIFIC INTERACTIONS, POPULATION DYNAMICS & SCALES STUDIED USING MOLECULAR MARKERS COMMUNITY STRUCTURE H. D. Loxdale 1, C. P. Brookes 2 & W. Powell 3, 1, 2, 3. Entomology and Nematology Dept., W. W. Murdoch 1 & S. L. Swarbrick 2, 1, 2. Dept. of Ecology, Evolution & Marine IACR-Rothamsted, Harpenden, Herts, AL5 2JQ, U.K. hugh.loxdale@bbsrc.ac.uk Biology, Univ. of California, Santa Barbara, CA, , USA There is considerable interest in the use of primary Hymenopterous parasitoids as biological Entomologists have discussed for decades whether, and under what circumstances, it is control agents in IPM strategies to combat aphids. Within agro-ecosystems, such strategies could better to release multiple natural enemies rather than the single "best" enemy to achieve involve the manipulation of extant parasitoid populations, encouraging them to move between biological control. Population dynamics theory provides some guidance, but no single crop and alternative or 'reservoir' hosts in nearby uncultivated land. For these approaches to answer. In practice, release of several to many species is common, and apparently succeed, knowledge of the population structure and dynamics of the parasitoid/s concerned is competing species of natural enemies coexist in many cases of successful biological highly desirable, along with information about host specificity, i.e. 'generalism' or 'specialism'. control. We will discuss the results of a field experiment in a citrus grove where Recently, we have demonstrated that morphologically similar primary parasitoids Aphidius ervi California red scale, Aonidiella aurantii, is under control, putatively by the parasitoid sensu lato attacking sympatric populations of pea aphid (Acyrthosiphon pisum) and nettle aphid Aphytis melinus, but other enemies are also present. Red scale density was increased (Microlophium carnosum) appear to display host specificity and reproductive isolation. Whilst experimentally and the responses of two parasitoid species and a number of predators are host forms of the parasitoids will readily cross and produce viable offspring in culture, field being measured. collected samples showed fixed allelic differences at the phosphoglucose mutase locus. The Index terms: Aonidiella aurantii, Aphytis melinus, biological control result emphasises the importance of thoroughly studying the population structure of 'parasitoid species' before assuming them to be 'generalist'. Besides such fundamental concerns about host specificity, if parasitoids are to be mass released or natural populations manipulated, it is important to understand 1, how far particular genotypes or strains travel; 2, how long particular genotypes/strains persist in the field; 3, whether there is gene flow between populations attacking different hosts or occupying different habitat patches and 4, how many times individual female parasitoids attack particular host colonies, as reflected in patterns of genetic variability. Detailed information on these various aspects is scarce. A major problem is the haplo-diploid reproductive system of parasitoids, which can result in populations becoming homozygous at isozyme loci. Because of this tendency, we have designed a suite of microsatellite DNA markers and are presently using these to investigate spatio-temporal parameters in the primary parasitoid, Diaeretiella rapae attacking the cabbage aphid, Brevicoryne brassicae infesting oilseed rape, Brassica napus in southern England. In this talk, I shall describe how the use of a range of polymorphic microsatellites is providing insights into the population structure and dynamics of D. rapae, including behaviour/ attack strategy and breeding systems, at spatial scales ranging from single leaf through to farm scale. It is hoped that the information gained can aid the design of IPM strategies as well as contributing to simulation models of parasitoid population spread and effectiveness. Index terms: Hymenoptera, Aphidius spp., Diaeretiella rapae, isozymes, microsatellites 207