Host plant-mediated variation in overwintering site quality: implications for the size and composition of populations of Acanthoscelides alboscutellatus (Coleoptera: Bruchidae)

This study provides an example of how variation in the quality of overwintering sites provided by the host plant of an insect seed predator can influence both the probability of overwintering survival and the size and composition of postwintering populations. Thus, the concept of host plant quality is extended to include variation in the suitability of the overwintering site of temperate region insects that overwinter within, or in habitats created by, their host plant. Adult Acanthoscelides alboscutellatus (Horn) (Coleoptera: Bruchidae) overwinter inside the fruit of Ludwigia alternifolia (L.) (Onagraceae). In early winter, however, fruits begin to dehisce, i.e., one or more of the fruit's four sides and/or top are shed. Variation in the onset and extent of dehiscence creates a range of overwintering habitats that vary in exposure to ambient conditions. In this study the frequency of possible overwintering sites in natural populations of L. alternifolia was determined by monitoring the phenology of fruit dehiscence from October through May in two populations for four years and for a third population for three years. Winter survivorship of adult A. alboscutellatus was assessed experimentally in eight environments representative of the conditions created by variation in dehiscence. These environments were produced by crossing four levels of exposure (degree of dehiscence) with two locations of the overwintering site, i.e., above or on the ground surface. The onset, phenology, and overall frequency of fruit dehiscence varied markedly among populations and years. Exposure, location, and their interaction had strong effects on survival and accounted for 80% of the observed variation in winter survival. Survivorship was higher on than above the ground, and in both locations decreased with increasing exposure. Thus, variation in fruit dehiscence among L. alternifolia populations will influence the size of postwintering A. alboscutellatus populations by dictating the quality of overwintering sites. Adult beetles that over-winter inside indehiscent fruit experience selection for small body size, associated with high mortality, when they attempt to exit the fruit at eclosion. As a consequence, the frequency of fruit dehiscence at eclosion coupled with the relative survival rates of adults within indehiscent fruit will determine the body size composition of postwintering populations and hence the response to selection for small body size in this species.     

Two‐tier morpho‐chemical defence tactic in Aethionema via fruit morph plasticity and glucosinolates allocation in diaspores

Fruit dimorphism and the production of glucosinolates (GSLs) are two specific life history traits found in the members of Brassicales, which aid to optimize seed dispersal and defence against antagonists, respectively. We hypothesized that the bipartite dispersal strategy demands a tight control over the production of fruit morphs with expectedly differential allocation of defensive anticipins (GSLs). In dimorphic Aethionema, herbivory by Plutella xylostella at a young stage triggered the production of more dehiscent (seeds released from fruit) than indehiscent fruit morphs (seeds enclosed within persistent pericarp) on the same plant upon maturity. Total GSL concentrations were highest in the mature seeds of dehiscent fruits from Aethionema arabicum and Aethionema saxatile among the different ontogenetic stages of the diaspores. Multivariate analyses of GSL profiles indicated significantly higher concentrations of specific indole GSLs in the diaspores, which require optimal defence after dispersal (i.e., seeds of dehiscent and fruit/pericarp of indehiscent fruit). Bioassays with a potentially coinhabitant fungus, Aspergillus quadrilineatus, support the distinct defensive potential of the diaspores corresponding to their GSL allocation. These findings indicate a two‐tier morpho‐chemical defence tactic of Aethionema via better protected fruit morphs and strategic provision of GSLs that optimize protection to the progeny for survival in nature.     

Evidence that an evolutionary transition from dehiscent to indehiscent fruits in Lepidium (Brassicaceae) was caused by a change in the control of valve margin identity genes

In the Brassicaceae, indehiscent fruits evolved from dehiscent fruits several times independently. Here we use closely related wild species of the genus Lepidium as a model system to analyse the underlying developmental genetic mechanisms in a candidate gene approach. ALCATRAZ (ALC), INDEHISCENT (IND), SHATTERPROOF1 (SHP1) and SHATTERPROOF2 (SHP2) are known fruit developmental genes of Arabidopsis thaliana that are expressed in the fruit valve margin governing dehiscence zone formation. Comparative expression analysis by quantitative RT‐PCR, Northern blot and in situ hybridization show that their orthologues from Lepidium campestre (dehiscent fruits) are similarly expressed at valve margins. In sharp contrast, expression of the respective orthologues is abolished in the corresponding tissue of indehiscent Lepidium appelianum fruits, indicating that changes in the genetic pathway identified in A. thaliana caused the transition from dehiscent to indehiscent fruits in the investigated species. As parallel mutations in different genes are quite unlikely, we conclude that the changes in gene expression patterns are probably caused by changes in upstream regulators of ALC, IND and SHP1/2, possible candidates from A. thaliana being FRUITFULL (FUL), REPLUMLESS (RPL) and APETALA2 (AP2). However, neither expression analyses nor functional tests in transgenic plants provided any evidence that the FUL or RPL orthologues of Lepidium were involved in evolution of fruit indehiscence in Lepidium. In contrast, stronger expression of AP2 in indehiscent compared to dehiscent fruits identifies AP2 as a candidate gene that deserves further investigation.     

Dynamics of the fungal symbionts in the gallery system and the mycangia of the ambrosia beetle,Xylosandrus mutilatus (Blandford) (Coleoptera: Scolytidae) in relation to its life history

The dynamics of the fungal symbionts in the gallery system and the mycangia of the ambrosia beetle,Xylosandrus mutilatus, were studied in relation to its life history using both isolation experiments and scanning electron microscopy (SEM). In the galleries,Ambrosiella sp. was predominant during the larval stages but its relative dominance gradually decreased during the development of the larvae. In contrast, yeasts (mainlyCandida sp.) andPaecilomyces sp. dominated continuously in the galleries after eclosion.Ambrosiella sp. was consistently stored in the mycangia in all adult stages, except in the teneral and overwintering adults when the other fungi were dominant. No fungal spores occurred in the mycangia of the adult beetles reared under aseptic conditions from the pupal stage, while onlyAmbrosiella sp. was stored in those reared from the teneral-adult stage. These results suggest that: (i) Xmutilatus is associated with at least three fungal species, among whichAmbrosiella sp. is the most essential food resource for development of the broods; (ii) immediately after eclosion, new female adults may take at least four associated fungal species, with no or incomplete selection, into their mycangia from the walls of the cradles; and (iii) conditions may well be produced in the mycangia of both matured and dispersing beetles whereby only the spores ofAmbrosiella sp. can proliferate.     

Genotypic effects on pollen morphology in sesame (Sesamum indicum L.)

Summary The morphology (shape, exine wall pattern, diameter, volume, surface area) of mature pollen grains from eight genotypes, four within each of two capsule types (dehiscent, indehiscent) was studied. The shape was a flattened sphere (oblate) with a P (polar axis diameter): E (equatorial axis diameter) ratio = 0.69. The exine wall pattern consisted of a series of furrows passing through the poles and intersecting the equatorial plane at right (90°) angles. In cross section, the furrows appeared to be associated with shallow U-shaped structures with the intine protruding between these structures. Over the eight genotypes, the diameter, volume, and surface area were 65 m, 147300 m³, and 13444 m², respectively. For all three related characters, highly significant differences between capsule type and genotypes within capsule type were obtained. For each character, the dehiscent capsule type mean was larger than the indehiscent capsule type mean with minimum overlap among the four genotype means within each capsule type. Possibly, the numerous and diverse pleiotropic effects associated with this simply-inherited recessive indehiscent capsule type character includes pollen dimensions.     

Host species preference and larval performance in the wood-boring beetlePhoracantha semipunctata F.

Adults of the wood-boring beetlePhoracantha semipunctata F. showed variability in their attractiveness to five varieties ofEucalyptus when presented with an array of logs in a natural setting. Logs of two host varieties (E. camaldulensis Dehnhardt and the hybridE. trabutii) attracted two to three times more adult beetles than did logs of other host species (E. cladocalyx F.,E. grandis Hill ex Maiden andE. tereticornis Small). In the field, high oviposition rates byP. semipunctata adults resulted in severe competition among larvae. Larval survivorship was low in field logs ofE. trabutii and high inE. cladocalyx logs, although these hosts were the most and least attractive to the adult beetles, respectively. However, when logs were hand infested at low larval densities, survivorship ofP. semipunctata larvae was highest in logs of bothE. camaldulensis andE. trabutii. These findings suggest that adult beetles in the field were most attracted to those logs ofEucalyptus species that represented the highest quality hosts for their progeny under conditions of reduced larval competition.     

Fruit size and shape: Allometry at different taxonomic levels in bird-dispersed plants

Summary The likelihood that a plant's seeds will be dispersed by fruit-eating birds may depend upon the size and shape of its fruits. Assuming that elongate fruits can be swallowed more easily than spherical fruits of equal volume and that plant fitness is enhanced by seed dispersal by many individuals and species of birds, natural selection should favour increasing fruit elongation with increasing fruit size in bird-dispersed plants. According to this view, this allometric pattern would be adaptive. Alternatively, fruit shape in bird-dispersed plants may be constrained by development or phylogeny. To determine whether there was any evidence to support the adaptive allometry hypothesis, we examined allometric relationships between length and diameter in fruits and seeds in a group of neotropical bird-dispersed plant species. Using the major axis technique, we regressed ln(diameter) on ln(length) for fruits and seeds at various taxonomic levels: (1) within individual trees ofOcotea tenera (Lauraceae) (2) among 19 trees within a population ofO. tenera, as well as among pooled fruits from multiple trees within 20 other species in the Lauraceae, (3) among 25 sympatric species within a plant family (Lauraceae) and (4) among 167 species representing 63 angiosperm families within a plant community in Monteverde, Costa Rica. At most taxonomic levels, a tendency for fruit length to increase more rapidly than fruit diameter among fruits (negative allometry) occurred more frequently than expected by chance. Estimated slopes of the regressions of fruit length on fruit diameter were < 1 within 15 of the 19 individualO. tenera trees, among tree means withinO. tenera, among pooled fruits within 16 of the 20 other species in the Lauraceae, among species means within the Lauraceae and among means of all bird-dispersed species in the lower montane forests of Monteverde. Seed allometry showed similar patterns, although for both fruits and seeds the broad confidence intervals of the slopes estimated by major axis regression overlapped 1 in many cases. Among the 63 Monteverde family means, fruit length and diameter scaled isometrically. Based on measurements of ontogenetic changes in fruit shape in a single species,O. viridifolia, we found no evidence that negative allometry in fruit shape within the Lauraceae was an inevitable consequence of developmental constraints. Instead, increasing elongation of fruits and seeds in certain plant taxa is consistent with adaptation to gape-limited avian seed dispersers. Contrary results from vertebrate-dispersed species from Malawi and Spain may reflect differences between the New and Old World in plant taxa, seed dispersers or evolutionary history.     

Population persistence of the parasitoid fly Zaira cinerea (Fallén) (Diptera: Tachinidae) utilizing multiple host carabid beetles with different seasonality and quality

Zaira cinerea (Fallén) is a parasitoid fly (Diptera: Tachinidae) that attacks adult carabid beetles. To better understand mechanisms of population persistence in this species, we examined seasonality of host beetle abundance, the frequency of parasitism, and the timing of fly eclosion. In addition, we evaluated host quality using numbers of larvae or puparia per individual beetle as a measure of quality. The fly parasitized only large carabids (≥15 mm body length); the lengths of fly puparia reached 7.4–10.8 mm during development in beetle abdomens, and larger hosts are likely essential. Of the 18 large carabid species collected in this study, we chose two, Carabus maiyasanus Bates and Leptocarabus procerulus (Bates), because they were large and abundant (87% of total catch). The two carabids had different phonologies; C. maiyasanus was abundant from spring to summer, and its abundance dropped sharply in autumn, while L. procerulus was abundant in autumn and rare from spring to summer except July. Parasitism was observed in all the months from May to November except June, and adult flies eclosed more than once a year (in early summer, late summer, and mid‐autumn), indicating that the species is multivoltine. Host quality of L. procerulus was higher than that of C. maiyasanus. Carabus maiyasanus was mainly used as a host from spring to summer, and L. procerulus was used in autumn. Thus, adult beetles of one or both species are available over most of spring, summer, and autumn, allowing population persistence of this fly species over time.     

THE RESPONSES OF DROSOPHILA MELANOGASTER TO ARTIFICIAL SELECTION ON BODY WEIGHT AND ITS PHENOTYPIC PLASTICITY IN TWO LARVAL FOOD ENVIRONMENTS

To investigate the potential response to natural selection of reaction norms for age and size at maturity, fresh body weight at eclosion was mass selected under rich and poor larval food conditions in Drosophila melanogaster. The sensitivity of dry weight at eclosion to the difference between rich and poor larval food was selected using differences in sensitivities among families. For both experiments, the correlated response to selection of age at eclosion was examined. The flies were derived from wild populations and had been mass cultured in the lab for more than six months before the experiments started. These flies responded to selection on body weight upwards and downwards on both rich and poor larval food. Selection on increased or decreased sensitivity of body weight was also successful in at least one direction. Sensitivity was reduced by selection upwards in a poor environment and downwards in a rich environment.     

Reproductive biology ofCistus ladanifer (Cistaceae)

The phenology, major floral characteristics, fruiting levels, and breeding system ofCistus ladanifer L. (Cistaceae), a common western Mediterranean shrub species, were studied in a southern Spanish population. The white, large (64 mm in diameter) flowers of this shrub appear during spring (March–May) and produce abundant pollen and nectar. In the year of study, flowers lasted up to three days, during which they were visited by a diverse array of insects including beetles, flies, and bees. Hand-pollinations revealed that flowers do not set any seed unless cross pollen is applied to the stigma. Microscopical observations indicate that self pollen tubes grow down the stigma but invariably fail to induce fruit maturation. At the plant level, all estimates of fecundity investigated (number of seeds per capsule, proportion of ovules developing into seed, and proportion of flowers setting fruit) were highly dependent on nearest neighbour distance, with isolated plants setting as little as 0% fruit. In contrast, plants within a clump often transformed into fruit as much as 90% of the flowers. At the population level, seed output was estimated to range between 3,000 and 270,000 seeds per plant during 1991.     

The effects of climate, host plant phenology and host fidelity on the genetics of apple and hawthorn infesting races ofRhagoletis pomonella

True fruit flies belonging to theRhagoletis pomonella (Walsh) sibling species complex have been proposed to speciate sympatrically by shifting and adapting to new host plants. Here, we report the results from a series of ecological and genetic experiments conducted at a study site near Grant, Michigan, U.S.A., aimed at clarifying the relationship between host specialization and reproductive isolation for these flies. Our findings indicate that apple (Malus pumila) and hawthorn (Crataegus mollis) infesting populations ofR. pomonella are partially allochronically isolated. Differences in the timing of adult eclosion account for part of the allochronic divergence, as apple adults emerge approximately ten days earlier than hawthorn flies in the field. Genetic analyses across different life history stages of the fly show that adults do not randomly move between apple and hawthorn trees, but trend to attack the same species of plant that they infested as larvae. Estimates of interhost migration from the allozyme data suggest that from 2.8 to 10% of the apple population is of hawthorn origin and that over 20% of the hawthorn population is of apple origin. The length and quality of the growing season appear to affect the genetic composition of the host races, as allele frequencies in the hawthorn population are correlated with ambient temperature and rainfall during the spring of the preceding year. Finally, allele frequencies for six allozyme loci displaying host associated differentiation also show significant linear regressions with the timing of adult eclosion within both races. These regressions establish a link between allozyme loci displaying inter-host differentiation and a developmental trait (adult eclosion) responsible for partially isolating the races. The slopes of the regressions are paradoxical, however, as they suggest that apple adults should eclose later, not earlier, than hawthorn flies. We conclude by discussing potential resolutions to the eclosion time paradox.     

Temperature and prey capture: opposite relationships in two predator taxa

Abstract 1. All other things equal, predator capture rates are expected to depend on encounter rate with prey, prey escape capability (including prey defences), and on predator agility. Ectotherm predators and their prey both respond to increasing temperature by increased activity, i.e. predators increase their search area and prey may enhance their escape capability. This means that, as temperature changes, the ability of a predator to catch prey will decrease, increase, or remain unchanged depending on the relative effect of temperature on predator and prey. Their responses may further be differentially moulded by light conditions depending on whether the predator is diurnally or nocturnally active. It was hypothesised that flying Diptera are vulnerable to carabid beetles only at low temperatures and over the full temperature range for spiders because carabids, in contrast to spiders, are not built to catch swiftly moving prey. 2. The first experiment examined the spontaneous locomotor activity of the predators and of fruit flies at different temperatures (5, 10, 15, 20, 25, and 30 °C) and light conditions (light, dark). A second experiment examined the effect of temperature and light on the predation rate of two carabid beetles (Pterostichus versicolor and Calathus fuscipes) and two spiders (Clubiona phragmitis and Pardosa prativaga) using fruit flies (Drosophila melanogaster) as prey. 3. All four predators and the fruit fly increased their locomotory activity at higher temperatures. Activity of the carabid beetles peaked at intermediate temperatures; spiders and fruit flies were most active at the highest temperatures. Predation rate of the spiders increased with temperature whereas the beetles caught flies only at low temperatures (5 and 10 °C). 4. Diurnal variation in temperature may bring different prey groups within the set of potential prey at different times of the day or at different seasons. The ability of many carabid beetles to forage at low temperatures may have nutritional benefits and increases the diversity of interactions in terrestrial food webs.     

Cracks or holes in the stems of oviposition plants provide the only exit for hatched larvae of diving beetles of the genera Dytiscus and Cybister

Diving beetles such as Dytiscus and Cybister species (Coleoptera: Dytiscidae) usually oviposit inside an aquatic plant stem beneath the surface of the water. The hatched larvae need to escape from the stem to intake oxygen from the air. To determine where larvae of these diving beetles hatch in the plant stem, the hatchability and escape rates in larvae of Dytiscus sharpi Wehncke, Cybister chinensis Motshulsky, Cybister lewisianus Sharp, and Cybister brevis Aubé were investigated under laboratory conditions. Hatchability of D. sharpi in the stem of Sagittaria trifolia L. (Alismataceae) was extremely low (8.2%). However, it was high (>90%) when late‐stage eggs (2–3 days before hatching) were isolated from the stem and kept in water. On the other hand, the hatchability of Cybister spp. was high (88–95%) in S. trifolia. Usually, Cybister spp. females bite a hole in the plant stem on oviposition. When the oviposition pore in the stem was plugged with glass wool, no larvae could escape from the stem, indicating that the oviposition pore was the only exit for hatched larvae of Cybister spp. In contrast, females of D. sharpi oviposited directly by making a crack in the stem of Oenanthe javanica (Blume) DC. (Apiaceae) without biting. Eggs grew to a length and diameter equal to the stem crack size 2–3 days before hatching. Dytiscus sharpi eggs isolated from O. javanica were artificially inserted into plant stems of O. javanica or S. trifolia (so‐called inserted egg model), and the hatchability and larval escape rates were determined. Larval escape strongly depended on the stem crack width of both O. javanica and S. trifolia, suggesting that the stem crack was an exit for hatched larvae of D. sharpi.     

Medicago truncatula f.laxicycla (Leguminosae), a new taxon with loose fruit coiling promoting rapid germination of the fruit-retained seeds

Medicago truncatula is a member ofMedicago sect.Spirocarpos, in which all 34 species have coiled fruit, usually tightly coiled, that permanently retain the seeds. A variant ofM. truncatula from Libya is unique for the species in possessing very loosely coiled fruits, and is here recognized as a new forma,M. truncatula f.laxicycla E. Small. In germination tests of a number of species ofMedicago, the unusual Libyan variant proved to be the only one in which rapid and simultaneous germination of most of the seeds occurred while still within a fruit. The loose coiling of the fruit of the Libyan variety appears to facilitate water entry and seedling escape. Its rapid germination might adapt it to respond quickly to intermittently available moisture, but at the cost of abandoning the strategy of intermittent germination adopted by other populations ofMedicago sect.Spirocarpos.     

Beetle pollination of peacock moraeas (Iridaceae) in South Africa

The peacock moraeas are South African geophytes withIris-like flowers that are characterized by broad outer tepals with iridescent spots. Three of the seven species were studied and found to be exclusively visited and pollinated by beetles. The primary pollinators were hopliine (Scarabaeidae) beetles in the generaPeritrichia, Monochelus, Anisonyx andAnisochelus. These beetles visit flowers for nectar, pollen and mating.Peritrichia rufotibialis was the primary pollinator ofMoraea villosa, P. abdominalis was the primary pollinator ofM. tulbaghensis, whileMonochelus sp. nov. was the primary pollinator of the third species,M. neopavonia. High levels of fruit set attest to the effectiveness of these beetles as pollinators. Average fruit set ranged from 83.5 ± 34.8% (M. villosa) to 97.2 ± 11.6% (M. tulbaghensis). Average seed set in the various populations was more variable, but was also quite high, ranging from 77.3 ± 40.8 (M. villosa) to 342.2 ± 115.0 (M. neopavonia) seeds per capsule. Although hopliine beetles are abundant and diverse in southern Africa and commonly visit flowers, this is the first well-documented report of pollination by these beetles.     

Sharing the same space: foraging behaviour of saproxylic beetles in relation to dietary components of morphologically similar larvae

1. Saproxylic beetles (Coleoptera) have particular requirements for dead wood. Little is known about their larval development, especially within intermediate and late stages of dead wood decay. 2. We studied the natural foraging behaviour of three saproxylic beetles with morphologically similar (i.e. convergent) larvae and similar habitat requirements –Cucujus cinnaberinus Scopoli (Cucujidae), Pyrochroa coccinea L., and Schizotus pectinicornis L. (Pyrochroidae) – examining dietary components using visual gut content analysis. 3. There were few significant differences in diet among the study species, but there were significant differences for the different dietary components in individual species. Guts of all three species included more plant and fungal material than animal. We also observed that with increasing body size larvae foraged significantly less on fungal material. We observed significant differences among species and selection with respect to body size during the overwintering period. Larvae swallowed more animal and less fungal material with increasing body size. 4. The study species seem to be opportunistic foragers, varying their foraging capability according to seasonality and age. They probably generally foraged woody material infested by filamentous fungi (i.e. xylomycetophagy), swallowing other material that is in their way while foraging, including animal parts and small arthropods. 5. We found that morphologically similar larvae do not differ much in their foraging behaviour even when sharing the same habitat. Larval size seems to be a useful predictor for foraging behaviour of saproxylic beetles within the same guild. The study species are probably occasional predators with less ability to forage on other animals than previously suggested.     

Host-associated fitness variation in a seed beetle (Coleoptera: Bruchidae): evidence for local adaptation to a poor quality host

The geographic distributions of many generalist herbivores differ from those of their host plants, such that they experience coarse-grained spatial variation in natural selection on characters influencing adaptation to host plants. Thus, populations differing in host use are expected to differ in their ability to survive and grow on these host plants. We examine host-associated variation in larval performance (survivorship, development time, and adult body weight) and oviposition preference, within and between two populations ofStator limbatus (Coleoptera: Bruchidae) that differ in the hosts available to them in nature. In one population,Acacia greggii (Fabaceae: Mimosoideae) andCercidium microphyllum (Fabaceae: Caesalpininoideae) are each abundant, while in the second population onlyC. floridum andC. microphyllum are present. In both populations, egg-to-adult survivorship was less than 50% onC. floridum, while survivorship was greater than 90% onA. greggii. Most of the mortality onC. floridum occurred as larvae were burrowing through the seed coat; very low mortality occurred during penetration of the seed coat ofA. greggii. Significant variation was present between populations, and among families (within populations), in survivorship and egg-to-adult development time onC. floridum; beetles restricted toCercidium in nature, without access toC. floridum, survived better and developed faster onC. floridum than beetles that had access toA. greggii. Large host effects on body size were detected for female offspring: females reared onA. greggii were larger than those reared onC. floridum, whereas male offspring wee approximately the same size regardless of rearing host. Trade-offs between performance onC. floridum andC. floridum were not detected in this experiment. Instead, our data indicate that development time and survivorship onC. floridum may be largely independent of development time and survivorship onA. greggii. Patterns of oviposition preference corresponded to the observed patterns of host suitability: in laboratory preference tests, beetles with access toA. greggii in nature tended to prefer this host more than beetles without access to this host in nature.     

The influence of weed-cover on the mortality imposed on artificial prey by predatory ground beetles in cereal fields

Summary Pitfall trapping was carried out in a field of winter wheat in the Vale of York to determine the levels of abundance of adult carabid and staphylinid beetles, (which formed the bulk of the natural predator complex) in the field. A point quadrat survey was carried out at the same time to assess the vegetation cover round each trap. Predation pressure by the beetles in the field was monitored using fruit fly (Drosophila) pupae as artificial prey. These artificial prey were attached to small cards inserted in the field adjacent to the pitfall traps.The numbers of beetles caught were found to be directly related to the frequency and density of Poa annua L. (annual meadow grass) the only abundant non-crop plant present at the time. More beetles were caught in areas where Poa was abundant than where Poa was scarce. This was probably related to the more suitable environmental factors offered by these of the wheat itself was found to be unrelated to captures.The number of fruit fly pupae taken was shown to be related to the numbers of carabid and staphylinid beetles present, and also to the type of vegetation occuring around each card.The implication of these results for the effects of predation on potential pest-outbreaks in the crop are discussed.     

Foonchewia coriacea,a new combination to replace F. guangdongensis (Rubiaceae)

Examination of both specimens and literature has shown that Mycetia coriacea (based on Adenosacme coriacea; Rubiaceae) has apically dehiscent dry capsules, quite different from the indehiscent berries of other species of the genus Mycetia. In various characters including the fruits, the species is found to be identical with the newly described species Foonchewia guangdongensis, the only species of the genus Foonchewia and the tribe Foonchewieae. Therefore, the new combination Foonchewia coriacea is here proposed to replace F. guangdongensis.