Stylosanthes sp. aff.S. scabra: a putative diploid progenitor ofStylosanthes scabra (Fabaceae)

Stylosanthes sp. aff.S. scabra is an undescribed taxon showing affinities with the allotetraploid speciesS. scabra, but distinct in a number of attibutes. Several collections show potential as forage for clay soils in northern Australia. Twelve accessions have been analysed using STS (sequence-tagged-sites) as genetic markers, and they all displayed STS phenotypes of typical diploid species. Taking into account their morphological similarities, the STS analysis provides strong evidence thatStylosanthes sp. aff.S. scabra might be a diploid progenitor of the allotetraploidS. scabra. This speculation was supported by cytological examinations. Somatic chromosome numbers of two of these accessions were counted and both were found to be diploid (2n = 20). The level of polymorphism among the 12Stylosanthes sp. aff.S. scabra accessions, estimated using randomly amplified polymorphic DNA (RAPD) as markers, was 7.8%, and the dissimilarity value betweenStylosanthes sp. aff.S. scabra andS. viscosa (the other putative progenitor ofS. scabra) was 89%.     

Species composition, comparative size and abundance of the genus Littoraria (Gastropoda: Littorinidae) from different mangrove strata along the East African coast

Variation in the abundance, distribution and size of four species of mangrove littorinid gastropods (genus Littoraria) was investigated using a nested sampling design at different spatial scales along the East African coast, from Tanzania to South Africa. Littorinid abundance and diversity decreased abruptly south of Inhaca Island at the southern end of the study area. All species presented a large-scale spatial variation in abundance, with L. subvittata showing the greatest abundance while L. intermedia was rare. Littoraria scabra and L. intermedia were found mainly at the seaward edge of the forests. Littoraria subvittata increased in abundance in the middle of the forest and towards the landward side. Littoraria pallescens occurred mainly at the seaward edge and in the middle areas in the Rhizophora zone. These small-scale variations show contrasting specific distribution patterns within the mangrove, likely reflecting different tolerances to physical factors and biological interactions. All species appeared decreased in shell height from north to south. Littoraria scabra was always significantly larger than other species at all mangrove study sites. Handling editor: P. Viaroli     

Antheseabhängige UV-Muster in Blütenständen von Asteraceen

The pseudanthia ofHeliopsis scabra andRudbeckia vulgaris (Asteraceae) were examined during the anthesis for differences in their UV patterns. Distinct changes in the reflectance and absorbance properties could be observed. The results suggest a close correlation between different stages of floral development and pollinator attraction.

Herrn Prof. Dr.Lothar Geitler zum 90. Geburtstag gewidmet.     

Identification of Diploid <Emphasis Type="Italic">Stylosanthes seabrana</Emphasis> Accessions from Existing Germplasm of <Emphasis Type="Italic">S. scabra</Emphasis> Utilizing Genome-Specific STS Markers and Flow Cytometry,and Their Molecular Characterization

Stylosanthes seabrana (Maass and ‘t Mannetje) (2n = 2x = 20), commonly known as Caatinga stylo, is an important tropical perennial forage legume. In nature, it largely co-exist with S. scabra, an allotetraploid (2n = 4x = 40) species, sharing a very high similarity for morphological traits like growth habit, perenniality, fruit shape and presence of small appendage at the base of the pod or loment. This makes the two species difficult to distinguish morphologically, leading to chances of contamination in respective germplasm collections. In present study, 10 S. seabrana accessions were discovered from the existing global germplasm stock of S. scabra represented by 48 diverse collections, utilizing sequence-tagged-sites (STS) genome-specific markers. All the newly identified S. seabrana accessions displayed STS phenotypes of typical diploid species. Earlier reports have conclusively indicated S. seabrana and S. viscosa as two diploid progenitors of allotetraploid S. scabra. With primer pairs SHST3F3/R3, all putative S. seabrana yielded single band of ~550 bp and S. viscosa of ~870 bp whereas both of these bands were observed in allotetraploid S. scabra. Since SHST3F3/R3 primer pairs are known to amplify single or no band with diploid and two bands with tetraploid species, the amplification patterns corroborated that all newly identified S. seabrana lines were diploid in nature. Flow cytometric measurement of DNA content of the species, along with distinguishing morphological traits such as flowering time and seedling vigour, which significantly differ from S. scabra, confirmed all identified lines as S. seabrana. These newly identified lines exhibited high level of similarity among themselves as revealed by RAPD and STS markers (>92% and 80% respectively). Along with the enrichment in genetic resources of Stylosanthes, these newly identified and characterized accessions of S. seabrana can be better exploited in breeding programs targeted to quality.     

蔓赤车叶绿体基因组结构及系统进化分析

蔓赤车(Pellionia scabra)属于荨麻科赤车属,是一种具有高营养价值的优质野菜。本研究以蔓赤车为材料,基于高通量技术方法完成叶绿体基因组测序、组装注释、结构解析及构建系统发育树,以此深入研究蔓赤车叶绿体基因组特征。结果表明,蔓赤车叶绿体基因组大小为153220 bp,GC含量为36.4%,属于典型的四分体结构。共注释到130个基因,其中85个蛋白编码基因,37个转运RNA基因,8个核糖体RNA基因;其中,有15个基因包含1个内含子,2个基因包含2个内含子,rps12存在反式剪接情况。蔓赤车叶绿体基因组可分为光合作用(43个)、自我复制(64个)、其他编码蛋白(7个)以及未知功能(4个)4大类基因。蔓赤车叶绿体基因组共检测出51073个密码子,其中编码亮氨酸(Leu)的密码子占比最大,密码子偏向使用A和U两种碱基。检测到72个简单重复序列位点,其中有58个单核苷酸、12个二核苷酸、1个三核苷酸和1个四核苷酸4种不同类型的简单重复序列(simple sequence repeats,SSRs)。蔓赤车IRb/SSC边界存在ycf1基因扩张现象。系统进化树显示,蔓赤车(Pellionia scabra OL800583)与庐山楼梯草(Elatostema stewardii MZ292972)、盘托楼梯草(Elatostema dissectum MK227819)、光叶楼梯草(Elatostema laevissimum var.laevissimum MN189961)亲缘关系最密切。基于蔓赤车叶绿体基因组的研究,旨在为蔓赤车物种鉴定、遗传进化及基因组学研究奠定理论基础。     

Geographical ecology and variation of plant-seed disperser interactions: southern Spanish junipers and frugivorous thrushes

Spatial and temporal predictability in the mutual selective pressures of plants and frugivorous birds is a prerequisite for coevolution to occur. I examine the interaction patterns of strongly frugivorous thrushes (Turdus spp.) and their major winter food plants (Juniperus spp., Cupressaceae) and how they vary in space and time. Spatial congruency, rarely considered in seed dispersal studies, is studied at three spatial scales: 1) the total species range; 2) regional distribution; and 3) local abundance and its variation between seasons. Southern Spanish frugivorous thrushes and junipers show very low congruence in distribution patterns at each of these scales. Most juniper species show geographic distributions that are nested within the geographic ranges of thrush species. Bird species showed greater habitat breadth values than plants and were found in a greater percentage of localities. The local bird abundance was strongly correlated across years and sites with the local availability of juniper cones. Cone production varied markedly between years, but the rankings for different species in different years were statistically concordant at mid-elevation and lowland sites. Both bird abundance and cone production showed greater temporal than spatial variability. Variation of cone productions at both temporal and spatial scales was greater than variability in bird abundance. Species with strong interactions of mutual dependence showed very low values of biogeographic congruence, caused by differences in geographic range and habitat specificity. This obviously limits the possibilities for pairwise, specific coevolution to occur. However, mutual effects of species groups are possible to the extent that the component species are ecologically interchangeable in their selective effects and other constraints on coevolution are not operating. The approach used here to examine the patterns of species interactions at different biogeographic scales might prove useful in comparative studies of plant-animal interactions.     

Crab: snail size-structured interactions and salt marsh predation gradients

We studied size-structured predator-prey interactions between blue crabs (Callinectes sapidus) and marsh periwinkles (Littoraria irrorata) with a combination of field studies, laboratory experiments and individual-based modeling. Size distributions of Littoraria differed among years at the same sites in a salt marsh and could largely be explained by dominance of strong cohorts in the population. At a given site, abundance increased with elevation above tidal datum. Size-selective predation by blue crabs does not appear to be an important regulator of snail size distributions but may have a major effect on local abundance. Laboratory studies indicated that predator-prey interactions between Callinectes and Littoraria are strongly size-dependent. Crabs were generally effective at feeding on periwinkles at size ratios greater than approximately 6 (crab width: snail length). At lower size ratios crabs were far less effective at manipulating the snails, which often survived but with damaged shells. An individual-based model which incorporated information about incidence of snail shell scarring (resulting from non-lethal interactions) and snail density, predicted reduced predation rates and smaller average crab size with distance from the low tide refugium for crabs.     

The northern geographic range limit of the intertidal limpet Collisella scabra: a test of performance, recruitment, and temperature hypotheses

A decline in abundance towards a species' range boundary is often interpreted as evidence of a decline in individual success, and is usually assumed to reflect a decline in suitable environmental conditions. Gradual declines towards high latitude range boundaries are frequently attributed to limitations on organismal tolerance of cold temperature. Rarely have these two assumptions been empirically tested. The intertidal gastropod Collisella scabra declines monotonically in abundance from 435 to <1 m^?2 over the northern 300 km of its geographic distribution. I examined temperature, adult performance (survival, growth, reproduction), and recruitment at five locations in this region of decline. Mortality ranged from 4.9 to 11.2% per month, but was highest at the lowest latitude study site. Growth rates ranged from 0 to 5.2 mm yr^?1, but were generally lower at lower latitude sites. Gonad development was high in the three populations examined, but the possibility of infrequent spawning at high latitude sites could not be excluded. Finally, a comparison of performance differences among populations with temperature revealed clear effects of temperature on both growth and mortality; however, the patterns were not consistent with a hypothesis of cold stress at the range boundary. Overall there was little evidence for either reduced performance or increasing cold stress in low density high latitude populations. Over the same 300 km, recruitment declined monotonically from a mean of six recruits per 625 cm² to less than one; suggesting that limitations on recruitment, rather that adult performance, are responsible for low abundance in marginal populations. Several hypotheses for the decline in recruitment are discussed in the paper and the most likely explanation appears to be an increase in the distance between populations at the range margin, reducing the chances that dispersing larvae find suitable habitat for settlement.     

Comparative analysis of genetic relationship and diagnostic markers of several taxa of Guizotia Cass. (Asteraceae) as revealed by AFLPs and RAPDs

Amplified fragment length polymorphism (AFLP) and random amplified polymorphic DNA (RAPD) were employed to examine the genetic relationship between Guizotia taxa, to suggest the taxonomic status of some of these taxa, and to identify their diagnostic markers. Results from AFLPs and RAPDs share some features in common, both revealing G. scabra ssp. schimperi as the most closely related taxon to G. abyssinica, and indicating that G. arborescens and G. zavattarii are the most divergent taxa. Most of the diagnostic markers revealed in this study were specific to G. arborescens and G. zavattarii. Our analysis suggests that G. scabra ssp. scabra, G. scabra ssp. schimperi, Chelelu and Ketcha are separate species. In this study, AFLP was found to be superior to RAPD in detecting genetic variation, in internal consistency of the data and in the fitness of its clusters to genetic similarity data. AFLPs revealed genetic relationship between Guizotia taxa that is more inline with the cytogenetic and hybridization studies than that revealed by RAPDs.     

A test of Brown's principle in the intertidal limpet Collisella scabra (Gould, 1846)

Aim Brown's principle predicts that a species will peak in density near its range centre, and decline gradually towards the margins of its geographical distribution. The decline is assumed to reflect a decrease in individual performance near range margins. I test this abundance–performance hypothesis by comparing patterns in density and size across the northern half of the geographical distribution of the marine patellogastropod Collisella scabra (Gould, 1846). Location Collisella scabra is a high intertidal patellogastropod species distributed along the Pacific coast of North America from Cape Mendocino (CA, USA) to southern Baja California (Mexico). I surveyed 11 research sites spanning c. 36–44° N. Methods In each of the 11 research sites I surveyed four distinct microhabitats, and compared spatial patterns in density and in the size of solitary limpets. Results Both density and size were highly variable across the species range. Density peaked near the northern range margin, and showed greater variance at small spatial scales (< 10 km) than at large scales (> 100 km). In contrast, large size occurred uniformly across the survey area, and size was strongly associated with microhabitat. Main conclusion Collisella scabra does not show spatial patterns of density or performance that are consistent with Brown's principle. The underlying assumptions of Brown's principle may conflict with specific characteristics of C. scabra's life history and/or patterns of environmental variation across its range. Because such conflicts may be common in a large number of marine and terrestrial species, the generality of Brown's principle is questioned.     

Flowering phenology,pollen flow and fruit production in the andean shrub Befaria resinosa

Summary In the eastern Andes of Colombia, the shrub Befaria resinosa (Ericaceae) has peaks of flowering that are separated by extended periods of low flower production. The effect that these fluctuations in flower production have on pollen flow was investigated by using fluorescent dye as a pollen analog. Dye applied to open flowers was dispersed over long distances more often during low flower production than during high flower production. Whether enhanced pollen dispersal during flowering lows is of benefit to individual plants is not clear. The proportion of flowers that set fruit is positively correlated with flower abundance, negating the possibility that increased pollen dispersal results in a higher rate of fruit production due to outbreeding effects. It is also difficult to attribute the pattern of fruit production to changes in pollinator visitation rates, which are negatively correlated with flower abundance in the case of hummingbirds and not correlated at all with flower abundance in the case of insects. An opportunistic, large-bodied hummingbird (Colibri coruscans) visits B. resinosa during high flowering and may be a particularly effective pollinator, accounting for some of the increase in the proportion of flowers setting fruit. Rainfall is positively correlated with flower production and may be an important factor in shaping flowering phenology, but it is not significantly correlated with the proportion of flowers setting fruits. The possibility that low-level flowering may counteract inbreeding that results from peak flowering is discussed.     

Prevalence of coccidia parasites (Protozoa) in red squirrels ( Sciurus vulgaris): effects of host phenotype and environmental factors

We investigated the relative importance of environmental factors versus host phenotype in determining parasite prevalence in Eurasian red squirrels ( Sciurus vulgaris). One hundred and forty-three fecal samples of 116 different squirrels collected in 2000 and 2001 from five study areas in the Italian Alps, were examined for intestinal protozoans. Two species of Eimeria were present with a medium to high prevalence in both years and in all areas, while two other species were rare, occurring only in some areas and not in all years. Cryptosporidium parvum had a high prevalence in the two study areas of the Western Alps, while in the three areas of the Central Alps it was recorded only once. The prevalence of Eimeria sciurorum and C. parvum fluctuated in parallel with squirrel density, suggesting a possible correlation between the presence of these protozoans and host density. A gender effect on E. sciurorum prevalence at low density could be explained by different space use patterns and social organization of males and females. C. parvum occurred more frequently in young squirrels, suggesting an acquired immunity in adults, but age-related susceptibility was not found for eimerian species. The coccidian community was more similar within than between regions, and study area and year were key parameters in predicting coccidia infection. There was no evidence of competition between coccidian species, but one positive interaction between E. sciurorum and E. andrewsi was observed. Our results suggest that the effects of geographic region, area features, and year effects probably related to fluctuations in host population density, were more important than individual phenotypic host characteristics in structuring the coccidian assemblage and determining levels of parasite prevalence in red squirrel populations.     

Variation and taxonomy ofFritillaria graeca (Liliaceae) in Greece

The geographic variation inFritillaria graeca, an endemic of Greece, is explored, using multivariate techniques. Eleven morphological features were measured in each of 630 individual plants from 38 localities throughout the range of the species.Scheffe's a posteriori test revealed an almost continuous geographic variation and did not identify groups clearly. Discriminant analysis of the groups derived from an F significance test ofMahalanobis distance resulted in five major groups on the first two discriminant axes representing the subspeciesgraeca, ionica, guicciardii, thessala and its var.othria. A diagnostic key to theF. graeca subspecies is provided.This paper is a part of a doctoral dissertation dealing withFritillaria in Greece, to be submitted to the department of Biology of the Aristotelian University of Thessaloniki.     

Examining the strength and possible causes of the relationship between fire history and Sudden Oak Death

Fire can be a dominant process in the ecology of forest vegetation and can also affect forest disease dynamics. Little is known about the relationship between fire and an emerging disease epidemic called Sudden Oak Death, which is caused by a new pathogen, Phytophthora ramorum. This disease has spread across a large, fire-prone portion of California, killing great numbers of oaks and tanoaks and infecting most associated woody plants. Suitable hosts cover a much broader geographic range, raising concern over where the disease may spread. To understand the strength and potential sensitivities of a fire–disease relationship, we examined geographic patterns of confirmed P. ramorum infections in relation to past fire history. We found these infections to be extremely rare within the perimeter of any area burned since 1950. This finding is not caused by spatial bias in sampling for the disease, and is robust to variation in host abundance scenarios and to aggregation of closely spaced sampling locations. We therefore investigated known fire-related factors that could result in significantly lower incidence of the disease in relatively recently burned landscapes. Chemical trends in post-fire environments can influence the success of pathogens like P. ramorum, either by increasing plant nutrient stress or by reducing the occurrence of chemicals antagonistic to Phytophthoras. Succession in the absence of fire leads to greater abundance of host species, which will provide increased habitat for P. ramorum; this will also increase intraspecific competition where these trees are abundant, and other density-dependent effects (e.g. shading) can reduce resource allocation to defenses. Despite these findings about a fire–disease relationship, a much deeper understanding is necessary before fire can be actively used as a tool in slowing the epidemic.     

A Review of the Biology of <Emphasis Type="Italic">Gambusia affinis</Emphasis> and <Emphasis Type="Italic">G. holbrooki</Emphasis>

Eastern and Western Gambusia (i.e., Gambusia holbrooki and G. affinis, respectively) are considered together here because these two fish species are very closely related, similar in appearance, similar in biology and often confused. Widely divergent attitudes have developed with regard to these fish with some viewing them as being highly beneficial to humans through controlling mosquitoes and the diseases they harbor, and others expressing concern about the negative impacts that these fish may have on other species with which they interact. Because of the widespread distribution, high levels of abundance, ease of capture and captive maintenance, and divergent attitudes, a very large and diffuse literature has developed with regard to these species. In fact, few fish species have been studied as much as or more than these two species combined. There has, however, been no comprehensive review of their biology published to date. As it is not possible to provide a comprehensive review of Gambusia biology in one reasonably sized document, I provide here a review of aspects of their biology at the level of species and individual. In another review I focused instead on the levels of population and species communities and consider the impacts that these fish have on mosquitoes and other organisms (Pyke, unpublished). As would be expected of such widespread and abundant species, Gambusia affinis and G. holbrooki are clearly very tolerant, adaptable and variable in their biology, at both an individual and population level. Both individuals and populations can tolerate, and often thrive within, a wide range of conditions and the abilities of individuals to do this are enhanced if they have time to acclimate to any changes. Populations can adapt through genetic or evolutionary changes in response to conditions that vary in space or time, and there is significant genetic variation within and between populations.     

Contrasting demographies and persistence of rare annual plants in highly variable environments

Spatial and temporal variation in critical life history traits differ markedly between two co-occurring, rare and endangered annual plants, Gilia tenuiflora arenaria and Chorizanthe pungens pungens, that have restricted, but overlapping geographic distributions in coastal habitats of central California, USA. Environmental variation was extreme during the 6-year study (1997–2002), with the greatest differences between an intense wet, warm El Niño year (1998), followed by a very dry, cool La Niña (1999). Both species have similar increases in adult survival and seed set with wetter, warmer weather in spring, but they differed in other traits: more Gilia germinated in years with high rainfall and temperature, while more Chorizanthe germinated in dry, cooler years; Gilia abundance increased with the number of years since the previous large El Niño event, while Chorizanthe abundance declined; and Gilia abundance was independent of the previous year’s seed set, while Chorizanthe density was directly related to the previous year’s seed set. The strong negative associations of Chorizanthe abundance with warm, wet weather and with time since the previous El Niño probably reflect the particular sequence of annual weather patterns from 1997 through 2002, especially the extremes in 1998 and 1999. Since it germinates readily in most years under a wide range of winter conditions and does not develop a long-lived seed bank, Chorizanthe seedling abundance reflects recent additions and depletions of its seed bank, rather than prevailing weather, per se. In contrast, Gilia seeds may remain in the seed bank for many years, until relatively rare winter conditions trigger significant germination. These species-specific demographies enhance persistence and coexistence of these species, but the mechanisms differ from each other and from those described for annuals in other highly variable environments.     

Comparison of habitat quality and diet of Colobus vellerosus in forest fragments in Ghana

The forest fragments surrounding the Boabeng-Fiema Monkey Sanctuary (BFMS) in central Ghana shelter small populations of Colobus vellerosus. Little is known about these populations or the ability of the fragments to support them, despite the fact that these fragments represent potentially important habitat for the colobus in this region. We compared the diet of three groups of C. vellerosus in the fragments to two groups in BFMS. We also examined the differences in plant species composition and food abundance among fragments. The study took place from June to November 2003. Dietary data were collected using scan sampling. Plant species composition and food abundance were evaluated using tree plots and large tree surveys. As in BFMS groups, leaves constituted the highest proportion of the diet of fragment groups, yet the colobus in fragments fed on more lianas than did those in BFMS. Over 50% of all species observed eaten by colobus in the fragments were not consumed in BFMS groups during the same season. Food abundance was similar between fragments and BFMS, although species composition differed. There was no relationship between the density of colobus and the density of food trees or percentage of food species, suggesting that other factors may be influencing the number of colobus present. This study highlights the broad dietary range of C. vellerosus, which may be a factor allowing its survival in these fragments.     

The prevalence of non-indigenous species in southern California embayments and their effects on benthic macroinvertebrate communities

The prevalence of non-indigenous species (NIS) in southern California embayments was assessed from 123 Van Veen grab samples collected in nine bays and harbors during the summer of 1998. NIS occurred in all but two samples. They accounted for only 4.3% of the 633 taxa but contributed 27.5% of the abundance. There was no significant difference in the proportion of NIS abundance among ports harboring large vessels, small boat marinas, and areas where boats were not moored. Three species accounted for 92% of the NIS abundance: a spionid polychaete worm Pseudopolydora paucibranchiata, a mytilid bivalve Musculista senhousia, and a semelid bivalve Theora ubrica. The NIS did not appear to have a negative impact at the overall community level since NIS abundance was positively correlated with the abundance and richness of other species. This may be due to biogenic structures built by P. paucibranchiata and M. senhousia that enhance the abundances of other macrofauna.     

Effects of seed abundance on seed scatter-hoarding of Edward’s rat (<Emphasis Type="Italic">Leopoldamys edwardsi</Emphasis> Muridae) at the individual level

Mast seeding is a common phenomenon, and has important effects on seed dispersal and hoarding by animals. At population level, the predator satiation hypothesis proposes that the satiating effect of a large amount of seeds on a relatively small number of predators benefits seed survival in mast-seeding years. However, the effect of mast seeding on the scatter-hoarding of rodents at the individual level is largely unknown. In this study, we investigated the effects of seed abundance (by simulating mast seeding and non-mast seeding) on the removal, consumption and scatter-hoarding of seeds of Camellia oleifera (Theaceae) by Edward’s rat Leopoldamys edwardsi (Muridae) in seminatural enclosures in southwest China. We wanted to test the masting-enhanced hoarding hypothesis, which suggests that rodents tend to scatter-hoard more seeds in mast-seeding years in order to occupy more food resources. Our results indicate that L. edwardsi tended to disperse and scatter-hoard more seeds of C. oleifera per night with increasing seed abundance, and to eat less seeds per night when there was a high level of seed abundance in the enclosure experiments. These results support the masting-enhanced hoarding hypothesis. This capacity of rodents may be an evolutionary adaptation to the mast-seeding phenomenon. Our results suggest that mast seeding benefits forest regeneration not only through the predator satiation effect at the population level, but also through increased hoarding by animals at the individual level. Hongmao Zhang and Jinrui Cheng have contributed equally to this work.     

Host selection and larval interactions among three primary parasitoids ofPlathypena scabra (Lep.: noctuidae)

Three hymenopteran parasitoids that attackPlathypena scabra (F.) larvae often oviposit into consecutive instars of the host. We investigated host discrimination by adults and competitive interactions among larvae of these three parasitoid species. Avoidance of superparasitism byCotesia marginiventris (Cresson) andDiolcogaster facetosa Ashmead was tested. Females of each species were presented either withP. scabra parasitized by a different female of the same species 6 h earlier or unparasitizedP. scabra. Under these conditions,C. marginiventris attacked similar numbers of parasitized and unparasitized hosts.D. facetosa attacked 31% fewer parasitized than unparasitizedP. scabra. The avoidance of multiple parasitism byD. facetosa was studied in a similar bioassay. AlthoughD. facetosa females parasitized fewerP. scabra that had been attacked byC. marginiventris 6 h previously, the reduction in parasitism was only about 23%. In competition studies, immatureD. facetosa were better competitors than immatureC. marginiventris. Aleiodes (=Rogas) nolophanae (Ashmead) was an inferior competitor against bothC. marginiventris andD. facetosa when the duration between parasitism events was 1 h, but their competitive ability increased when they multiply parasitized hosts at least 32 h after the initial oviposition.