Attraction of female fungus gnats,Lycoriella ingenua,to mushroom‐growing substrates and the green mold Trichoderma aggressivum

To evaluate the attractiveness of several mushroom‐growing substrates to the female mushroom fly Lycoriella ingenua (Dufour) (Diptera: Sciaridae), a pest of the cultivated white button mushroom, Agaricus bisporus (JE Lange) Emil J Imbach (Agaricales), we developed a two‐choice, static‐flow olfactometer. Behavioral assays using this olfactometer indicated that mushroom compost with A. bisporus mycelia growing in it was not more attractive than compost lacking growing mycelia. We also found that female flies were more attracted to compost lacking A. bisporus mycelia than to the actual commodity, the white button mushroom fruiting bodies. Flies were not, however, attracted to sterilized compost, suggesting the attraction is due to volatiles produced by microbial metabolism in the compost. We also found that female L. ingenua flies were attracted to the mycoparasitic green mold Trichoderma aggressivum Samuels & W Gams (Hypocreales). Flies preferred mushroom compost that had T. aggressivum growing in it over compost lacking T. aggressivum, providing an experimental outcome consistent with the anecdotal belief that L. ingenua flies are vectors of T. aggressivum spores that can infest mushroom‐growing houses.     

Little effect of delayed mating on fecundity or fertility of female fungus gnats Lycoriella ingenua

The effect of delayed female mating for the mushroom fungus gnat Lycoriella ingenua is investigated. We examine the effect of delaying female mating on the fertility and egg viability of female flies that have a mating delay of 0–5 days after emergence. Male fly age is held constant. Female age does not impact male acceptance and most flies copulate within seconds of pairing. We find that female flies experiencing mating delays of 0–4 days after emergence lay a similar number of eggs onto artificial substrates. Females that experience a mating delay of 5 days lay 54% fewer eggs than those that mate on day 0 (day of emergence). There is no effect of mating delay on the percentage of larvae that emerge. The results of the present study indicate that mating delays have little effect on the fertility or fecundity of the mushroom fungus pest L. ingenua.     

云南食用菌眼蕈蚊分类及优势种分析

本文报道了云南省各食用菌栽培地眼蕈蚊科（Sciaridae）害虫共6属11种, 其中异迟眼蕈蚊Bradysia difformis Frey为中国新纪录种, 独刺普眼蕈蚊Cosmosciara perniciosa Edwards为中国新记录属和种, 并提供了云南省食用菌眼蕈蚊种类检索表。研究标本均保存于云南农业大学昆虫系标本室。根据各地标本采集数据对不同食用菌上眼蕈蚊种类优势度进行了分析, 结果表明平菇厉眼蕈蚊Lycoriella pleuroti Yang et Zhang和异迟眼蕈蚊B. difformis Frey为云南省食用菌上眼蕈蚊的主要优势种类。     

Evaluation of a genetically selected strain of Steinernema feltiae against the mushroom sciarid Lycoriella mali

The control potential of a strain (ScP) of Steinernema feltiae genetically selected against the mushroom sciarid Lycoriella solani, was evaluated for the management of L. mali. Trials were conducted at two commercial mushroom farms with high and low levels of fly infestation. The efficacy of the ScP strain was compared with the SN strain of S. feltiae and the chitin synthesis inhibitor, diflubenzuron. At low densities of L. mali, the two strains did not differ in efficacy and caused 85–94% reduction in fly populations. At high fly densities with a mixed infestation of the phorid fly, Megaselia halterata, the ScP stain caused 56–83% reduction in L. mali populations whereas the SN strain caused 51–73% reduction. Two doses of the improved strain (0.5 times 10⁶ and 1.0 times 10⁶ infective juveniles per m² cropping area) did not differ in efficacy from diflubenzuron which caused 80% reduction in L. mali populations. The lower dose (0.5 times 10⁶) of the SN strain was less effective than diflubenzuron. The ScP strain had a major advantage over the SN strain in persistence in casing material. Nematodes had no significant effect on mushroom yields.     

Evaluation of the behavioural response of the flies Megaselia halterata and Lycoriella castanescens to different mushroom cultivation materials

A static‐air olfactometer was used to investigate the behavioural responses of adult female phorid [Megaselia halterata (Wood) (Diptera: Phoridae)] and sciarid [Lycoriella castanescens (Lengersdorf) (Diptera: Sciaridae)] flies to the commercial white mushroom, Agaricus bisporus (Lange) Imbach, grown on a standard pasteurised composted substrate. The attraction of the flies was measured in relation to four test materials: composted substrate spawned with A. bisporus mycelium for 4 days and 14 days, uncolonised composted substrate, and A. bisporus sporophores. The experiment was done according to a 4 × 4 × 4 Latin cube design, and the results were analysed using a generalised linear model. It was found that both the occasion on which a bioassay was run and the position of the olfactometer within a 4 × 4 array could affect the proportion of the fly population responding to a test material. Megalesia halterata preferred spawned compost to unspawned compost, and the level of response to compost spawned for 14 days was greater than to compost spawned for 4 days. In contrast, L. castanescens were attracted equally to all of the materials tested. Overall, L. castanescens showed a greater level of activity than M. halterata, and was more likely to enter the pitfall traps in the olfactometer. For both M. halterata and L. castanescens, the type of test material affected the numbers of adult flies of the F₁ generation that emerged from it following oviposition. The highest numbers of emerging M. halterata were obtained from a composted substrate spawned for 4 days, and none emerged from the unspawned compost. Emergence of L. castanescens was highest from the uncolonised composted substrate, and there was a negative relationship between emergence and the amount of mycelium in the composted substrate. The results are consistent with the use of volatiles in the detection of oviposition sites by both species; however, further studies of the materials will be necessary to determine precisely which oviposition cues the insects use.     

Effects of the paedogenetic mushroom cecid, Heteropeza pygmaea (Diptera:Cecidomyiidae) on cropping of the cultivated mushroom (Agaricus bisporus)

When introduced into a mushroom crop at rates of 2, 20 or 200 larvae/tray (0.56 m²), the mushroom cecid, Heteropeza pygmaea, caused significant reductions in both yield and number of mushrooms in relation to the infestation level. The reductions were greater when the larvae were introduced at spawning rather than at casing. The yield and number of infested (unmarketable) mushrooms increased significantly in relation to the initial infestation level. Just two H. pygmaea larvae, introduced at spawning, resulted in cecid populations that caused a 12% loss in total yield in addition to a 7% loss due to spoilage. Loss assessment in the future, therefore, should take into account both yield suppression and spoilage. There was little effect of cecid infestation on flush timing and mushroom size was only affected in the fourth flush, when a significant reduction (27%) was shown at the highest infestation rate at spawning.     

The interaction of a Botanophila fly species with an exotic Epichloë fungus in a cultivated grass: fungivore or mutualist?

Epichloë spp. (Ascomycetes: Clavicipitaceae) are endophytic fungii of Pooid grasses that cause choke disease, the suppression of seed production. They also host Botanophila spp. (Diptera: Anthomyiidae), the larvae of which feed on the fungus. Studies on Epichloë elymi on wild grasses indicate that the flies transfer spermatia between Epichloë mating types, thereby affecting cross‐fertilization, suggesting that the fungus–fly interaction reflects obligatory mutualism. Epichloë typhina, inadvertently introduced into western USA, was first detected in cultivated Dactylis glomerata L. fields in 1996. It spread rapidly, raising concerns about impacts on seed production. The present study was conducted to address questions pertaining to the occurrence and nature of the fungus–fly interaction in the new habitat of E. typhina. The first report of an endemic Botanophila species associated with E. typhina in Oregon is presented here. Surveys of D. glomerata fields indicated no correlation between fly abundance and fungal fertilization. In one field, no fly eggs or larvae were detected, but fertilized stromata were universally present. The fly was established in the remaining 12 fields surveyed, but while the number of stromata with fly larvae ranged from 6 to 98%, stromata development was uniform. Up to 10 larvae were present on a stroma, and these consumed >90% of the perithecia. Comparisons of pupal weights indicated that the fungal resource was not limiting, even at high larval densities. An exclusion study in a D. glomerata field also indicated that E. typhina fertilization occurred without the fly. In Oregon, the fly clearly benefits from the association with the fungus, but there is no evidence of benefit to the fungus. Thus if obligatory mutualism in the fungus–fly relationship described from the midwestern USA is the norm, our studies suggest a shift in the interaction to one of simple foraging on the fungus by fly larvae.     

The use of chemicals, antagonists, repellents and physical barriers for the control of Lycoriella auripila (Diptera: Sciaridae), a pest of the cultivated mushroom Agaricus bisporus

The sciarid, Lycoriella auripila, is a serious pest of commercial mushroom production. A series of trials demonstrated that the use of early, specifically-targeted, treatments of insecticides and/or antagonists and repellents, which distance treatment time from crop harvest, have the potential to play a useful part in the control of initial and subsequent generations of this pest. Of the treatments examined, those involving a drench treatment of the compost at filling (before pasteurisation) proved to be the most effective. Cyromazine and diflubenzuron were the most active insecticides tested, with cyromazine achieving a superior level of control of the initial infestation. Repellents and antifeedants were also effective, with calcium oxalate and sinapic acid both achieving about 50% control when applied at filling. Treatments applied later during the production cycle, unless in combination with a treatment at filling, were progressively less effective at controlling both the initial sciarid infestation and later generations of larvae. Multiple treatments caused greater reductions in fly populations than did the single treatments and continued to do so throughout the cropping cycle, the greatest reduction in the initial generation (79%) occurring with a triple treatment of cyromazine. With the exception of some diflubenzuron treatments, those that were effective resulted in increases in yield. The use of a physical paper barrier caused significant increases in both fly numbers and total yield.     

The predatory mite Hypoaspis miles: biological and demographic characteristics on two prey species, the mushroom sciarid fly, Lycoriella solani, and the mould mite, Tyrophagus putrescentiae

The biology of Hypoaspis miles Berlese (Acarina: Hypoaspidae) fed on mushroom sciarid larvae (Lycoriella solani Winnertz) (Diptera: Lycoriidae) and mould mites (Tyrophagus putrescentiae Schrank) (Acari: Acaridae), was investigated by laboratory experiments at 20 °C, 75% r.h. and LD16:D8 hours. H. miles had a significantly shorter development time and a significantly lower juvenile mortality when fed on sciarid larvae than on mould mites, the development time being 14.5 days and the mortality 3.5% on the former prey. The preoviposition and postoviposition periods of H. miles were not uninfluenced by the prey species and were 5–9 and 32–37 days, respectively. Oviposition periods of 53.2 and 68.5 days and female longevities of 82 and 109.6 days were observed on diets of sciarid larvae and mould mites, respectively. Male longevity (168–219 days) was uninfluenced by the prey species. The egg production of H. miles on sciarid larvae was estimated to be 44.4 ± 4.33 eggs per female, as compared to 22.43 ± 1.79 eggs per female on mould mites. The sex-ratio of the offspring was significantly influenced by the prey species, the ratios (/(+)) being 0.66 on sciarid larvae and 0.54 on mould mites. The net reproductive rate (R₀) for H. miles fed on sciarid larvae was approximately 27 which was three times higher than for mites feeding on mould mites. The innate capacity of increase (r_m) was highest (0.0747 day^–1) when sciarid larvae served as food, giving a doubling time of 9.3 days as compared to 12.8 days on mould mites. The generation times were 44.28 on sciarid larvae and 40.67 days on mould mites. The daily food consumption rate of juvenile and adult H. miles was 0.24 and 0.86 sciarid larvae and 10.8 and 21.7 mould mites, respectively. In terms of weight consumed, however, the consumption of sciarid larvae was 2–3.5 times the weight of mould mites. The ratio of females to males influenced the oviposition period and egg production of H. miles, with virgin females laying fewer eggs over a longer period of time as compared with females with access to males. The egg production in relation to the sex-ratio was described by models predicting a maximum number of eggs per female of 22.3 to be attained at a sex ratio of 0.69 (/(+)) and a maximum daily number of eggs per female of 0.33 to be attained at a sex ratio of 0.37 (/(+)).     

Effect of constant temperatures on development of the walnut husk fly,Rhagoletis completa

The developmental rates of various life stages ofRhagoletis completa Cresson (Diptera: Tephritidae) were determined in the laboratory at seven different constant temperatures: 8, 12, 16, 20, 24, 28, and 32±1°C, RH 80±10%, photoperiod L 16∶D8. Preoviposition developmental rate was fastest at 28°C (10±1 days, mean±SD) and slowest at 12°C (26±1 days). About 83% of the females deposited eggs at 20 and 24°C and only 25% oviposited at 32°C. Females laid the highest number of eggs at 24°C and the lowest at 8°C. Egg development increased with increasing temperatures up to 28°C, then declined. The fastest egg development was noticed at 28°C (55±1 h) and slowest at 8°C (389±2 h). Over 90% egg hatch was observed at temperatures between 12 and 32°C, but decreased to 73% at 8°C. Larval development was fastest also at 28°C (20±0.2 days). Over 65% pupation was recorded at 20 and 24°C, but decreased to 15% at 32°C and 12% at 8°C. Pupal development was most rapid at 24°C (53±1 days) and slowest at 8°C (162±2 days). More than 70% of adult emergence was noticed in treatments between 16 and 24°C but decreased to 20% at 8°C. Based on a linear regression model of temperature-development rate relationship, the lower developmental thresholds were determined to be 6.6, 5.3, 2.9, and 5°C for preoviposition, egg, larval, and pupal stages, respectively. Based on a non-linear developmental rate model, the upper developmental thresholds were 34°C for preoviposition, egg, and larval stages and 30°C for pupal stage.     

Comparative effects of three insect growth regulator insecticides and a dipteran-active strain of Bacillus thuringiensis on cropping of the cultivated mushroom Agaricus bisporus

Three insect growth regulator insecticides and an entomopathogenic strain of Bacillus thuringiensis (GC327), products effective against the mushroom sciarid, Lycoriella auripila, were compared for their effect on mushroom cropping. Cyromazine and diflubenzuron were applied as a surface drench to mushroom compost before or after pasteurisation (at filling or spawning, respectively); admixed into casing material (at casing); or at a combination of these times. Hexaflumuron and GC327 were applied only at filling and casing, respectively. The presence of the target pest, L. auripila, had no effect on treatment trends, although it was accounted for in the analysis by use of a yield model. The trial was notable for the disparate effects that cyromazine and diflubenzuron casing treatments had on mushroom cropping. Cyromazine treatments that included application at casing resulted in increases in yield, compared to the untreated control whereas, with diflubenzuron, the opposite was true, with treatment at casing alone causing the greatest reduction overall (10%). GC327 applied at casing was also conspicuous for giving a 13% increase in yield. Treating the crop at casing with either cyromazine or GC327, therefore, resulted in a 15% or 24% increase in yield, respectively, compared to a similar treatment with diflubenzuron. Hexaflumuron applied at filling caused increases in yield compared to application of cyromazine at filling and cyromazine or diflubenzuron at spawning. There were also effects on crop timing. The addition of a cyromazine casing treatment normally caused the distinct flushes of mushrooms to be produced significantly earlier than the untreated control (up to 2.5 days), as did GC327. With diflubenzuron, the earlier flushes were only produced by those treatments that did not include a casing application. The combinations that included a casing treatment with diflubenzuron initially produced mushroom flushes earlier than the untreated control. They became either synchronous with the control or they were delayed. From the crop tolerance perspective, therefore, cyromazine and GC327 would be the sciarid control products of choice for a commercial mushroom grower.     

Relationships between temperature, development and survival of different life stages of the tomato fruit fly, Neoceratitis cyanescens

The development and survival of female Neoceratitis cyanescens (Bezzi) (Diptera: Tephritidae) from egg to complete ovarian maturation were studied in the laboratory at five different constant temperatures: 15, 20, 25, 30, and 35 °C. The aim of this study was to get information on the influence of temperature on pre-mature stages, as a prerequisite to optimise rearing procedures and to understand temporal and geographical patterns of fruit fly occurrence. The developmental rate of the different life stages increased linearly with increasing temperatures up to 30 °C. The fastest development of pre-mature stages was recorded at 30 °C (22±1 days) and the slowest at 15 °C (98±3 days). The day-degrees requirements (K) to complete total development were 432.6 day-degrees. Lower temperature thresholds were 11.4, 11.9, 10.0, and 11.1 °C for egg, larval, pupal stages and ovarian maturation, respectively. The number of adults obtained from an initial batch of 100 eggs reached a maximum (64) at 25 °C. At 35 °C, no adults emerged. Larval developmental time was significantly shorter in green tomato fruits than in potato tubers at 15, 20, and 25 °C. Mortality rate of larvae was higher in green tomato fruits than in potato tubers at 25 and 30 °C.     

Host-plant susceptibility to the carrot fly, Psila rosae. 2. Suitability of various host species for larval development

Several apiaceous and two asteraceous species were tested for their suitability to support larval development of the carrot fly. Plants grown in pots or transplanted from seed beds into pots, were inoculated with a specific number of eggs. Pupae and non-pupated larvae were collected 6–7 wk after inoculation. Both the number and weights of pupae produced varied widely among the species. Cultivated carrots Daucus carota sativus often gave rise to only moderate numbers of pupae, but these invariably attained the highest weights. Pimpinella major was the only apiaceous plant tested that did not yield any carrot flies. The two asteraceous plants Cichorium intybus and Tanacetum vulgare failed to support larval development. Total carrot fly biomass produced per plant was influenced by both the host species and the root weight. Emergence rates of adult flies were positively correlated with pupal weights. Small individuals tended to have a longer total developmental time from egg to adult fly.     

Effect of nutritional parameters on laccase production by the culinary and medicinal mushroom, Grifola frondosa

Summary Extracellular laccase in cultures of Grifola frondosa grown in liquid culture on a defined medium was first detectable in the early/middle stages of primary growth, and enzyme activity continued to increase even after fungal biomass production had peaked. Laccase production was significantly increased by supplementing cultures with 100–500 (M Cu over the basal level (1.6 mM Cu) and peak levels observed at 300 mM Cu were ∼ ∼7-fold higher than in unsupplemented controls. Decreased laccase activity similar to levels detected in unsupplemented controls, as well as an adverse effect on fungal growth, occurred with further supplementation up to and including 0.9 mM Cu, but higher enzyme titres (2- to 16-fold compared with controls) were induced in cultures supplemented with 1–2 mM Cu²⁺. SDS-PAGE combined with activity staining revealed the presence of a single protein band (M _r ∼ ∼70 kDa) exhibiting laccase activity in control culture fluids, whereas an additional distinct second laccase protein band (M _r␣∼ ∼45 kDa) was observed in cultures supplemented with 1–2 mM Cu. Increased levels of extracellular laccase activity, and both laccase isozymes, were also detected in cultures of G. frondosa supplemented with ferulic, vanillic, veratric and 4-hydroxybenzoic acids, and 4-hydroxybenzaldehyde. The optimal temperature and pH values for laccase activity were 65 °C and pH 2.2 (using 2,2′-azinobis(3-ethylbenzthiazoline-6-sulfonate) {ABTS} as substrate), respectively, and the enzyme was relatively heat stable. In solid-state cultures of G. frondosa grown under conditions adopted for industrial-scale mushroom production, extracellular laccase levels increased during the substrate colonization phase, peaked when the substrate was fully colonized, and then decreased sharply during fruit body development.     

Effects of intraspecific larval competition on the development of the African buffalo fly Haematobia thirouxi potans

The effects of larval crowding on development, survival and size of the African buffalo fly, Haematobia thirouxi potans (Bezzi), were examined in small (10 or 20 g) and 1 000 g masses of cattle dung in the laboratory at 25°C. Dung was infested with fly eggs at densities which ranged from 0.05 to 32.0 eggs per g dung; in most cases 90–100% of eggs hatched. The duration of larval developmentin 10 g dung masses was extended by larval crowding at densities above 0.8 eggs per g dung and the development period with 32 eggs per g dung (11 days) was double that observed in uncrowded dung masses. Both size and survival decreased with increasing larval density, but stunting was observed at lower densities than those which reduced survival and so size was the more sensitive index of the adequacy of the larval environment. The effects of larval crowding became evident at lower larval densities in the 1 000 g dung masses than in the 10 g dung masses. There was a minimum size below which third instar larvae failed to pupariate. The probability of survival was related to pupal size and a high proportion of the smaller individuals failed to eclose.

---

Effets de la competition intraspécifique sur le développement des larves, la taille des pupes et la survie d'Haematobia thirouxi potans

Résumé Les effets du surpeuplement larvaire sur le développement, la survie et la taille d'Haematobia thirouxi potans, ont été examinés sur de petites quantités de bouse (10 et 20 g) et de plus importantes (1 000 g), au laboratoire à 25°C. Les bouses étaient contaminées avec des oeufs de la mouche à des densités de 0,05 à 32 oeufs par gramme de bouse. Dans la plupart des cas le taux d'éclosion était de 90–100%. La durée du dévelopement larvaire dans 10 g de bouse a été prolongée pour les densités supérieures à 0,8 oeuf per g, et la durée développement pour 32 oeufs per g (11 jours) était le double de celle obtenue grand il n'y avait pas surpeuplement. La taille et la survie diminuent toutes les deux avec la densité larvaire, mais la miniaturisation était observée à des densités où la survie n'était pas modifiée; ainsi la taille est un indice plus sensible de l'adéquation de l'habitat larvaire. Les effets du surpeuplement larvaires deviennent clairs à des densités plus faibles avec 1 000 g de la bouse qu'avec 10 g. Il y a eu une taille minimale endessous de laquelle les larves étaient incapables de former une pupe. La probabilité d'éclosion était liée à la taille de la pupe, et une plus forte proportion de petits individus ne sont pas parvenu à éclore.

     

盐雾胁迫对舟山海岛7个造林树种存活和生长的影响

以普陀樟﹝Cinnamomum japonicum var. chenii ( Nakai) G. F. Tao〕、舟山新木姜子﹝Neolitsea sericea ( Bl.) Koidz.〕、红楠( Machilus thunbergii Sieb. et Zucc.)、全缘冬青( Ilex integra Thunb.)、石栎﹝Lithocarpus glaber ( Thunb.) Nakai〕、厚叶石斑木﹝Raphiolepis umbellata ( Thunb.) Makino〕和滨柃﹝Eurya emarginata ( Thunb.) Makino〕7个舟山海岛造林树种为研究对象,用浓度18 mg·g-1盐水通过盐雾发生装置每日喷雾0.0(对照)、0.5、1.0和2.0 h,并连续喷雾35 d,对翌年生长季各树种的形态特征、存活率和不同部位的干质量进行测定,并据此确定各树种的耐盐雾性。结果表明：随盐雾日处理时间及胁迫天数的延长,7个树种幼苗均表现出不同的受害症状并逐渐加重,但各树种的受害程度有差异。盐雾日处理0.5、1.0和2.0 h石栎幼苗的存活率,以及盐雾日处理2.0 h红楠、舟山新木姜子和滨柃幼苗的存活率均显著低于对照,但不同盐雾日处理时间对普陀樟、全缘冬青和厚叶石斑木幼苗的存活率均无显著影响。与对照相比,每日短时间的盐雾处理对普陀樟和全缘冬青幼苗的苗高和地径无显著影响,但随盐雾日处理时间延长二者的苗高和地径显著下降;盐雾日处理0.5、1.0和2.0 h,红楠、舟山新木姜子和滨柃幼苗的苗高总体上显著下降,厚叶石斑木幼苗的苗高则显著高于对照,但它们的地径总体上与对照无显著差异。每日短时间盐雾处理对普陀樟和滨柃幼苗单株的叶、根、茎干质量及总干质量均无显著影响,但随盐雾日处理时间的延长,二者单株的不同部位干质量及总干质量均逐渐下降;盐雾处理可导致舟山新木姜子、红楠、全缘冬青和石栎幼苗单株的不同部位干质量及总干质量显著或极显著下降,且降幅总体上随盐雾日处理时间的延长而增大,其中石栎幼苗单株的不同部位干质量及总干质量均最低;盐雾处理对厚叶石斑木幼苗生长则有一定的促进作用,使其单株的不同部位干质量及总干质量不同程度增加,但随盐雾日处理时间的延长增幅减小。盐雾处理对供试各树种叶、茎和根的质量比以及根冠比有不同的影响效应,其中盐雾胁迫造成各树种不同程度落叶,使多数树种根冠比增大,但全缘冬青和厚叶石斑木的根冠比则有所下降。根据实验结果,结合供试树种在舟山海岛的生长环境,初步确定厚叶石斑木的耐盐雾性最强,全缘冬青、普陀樟和滨柃的耐盐雾性次之,红楠和舟山新木姜子的耐盐雾性较弱,石栎的耐盐雾性在7个树种中最弱。     

The influence of different aphid prey species on the biology and life table parameters of Propylaea japonica

The influence of three aphid prey species – Aphis craccivora Koch, Megoura viciae Buckton and Rhopalosiphum maidis (Fitch) – on the biology of Propylaea japonica (Thunberg) was studied under laboratory conditions. The development, survivorship, longevity, reproduction and life table parameters of P. japonica differed significantly among different treatments. The shortest developmental period of P. japonica (from first-instar larvae to adult) was observed on A. craccivora, whereas the longest was observed on M. viciae. The highest survivorship was observed on A. craccivora, and the lowest survivorship was observed on M. viciae. The highest sex ratio, fecundity and the shortest pre-oviposition period were observed when A. craccivora was used as prey. The longevities of P. japonica females and males did not differ significantly when reared on different aphid species. The highest values of net reproductive rate, intrinsic rate of increase and finite rate of increase were observed on A. craccivora. The results suggest that A. craccivora is a suitable prey for P. japonica among the three aphid species tested and can serve as a diet for the mass rearing of P. japonica under laboratory conditions for possible use in integrated pest management.     

Disentangling the effects of plant species invasion and urban development on arthropod community composition

Urban development and species invasion are two major global threats to biodiversity. These threats often co‐occur, as developed areas are more prone to species invasion. However, few empirical studies have tested if both factors affect biodiversity in similar ways. Here we study the individual and combined effects of urban development and plant invasion on the composition of arthropod communities. We assessed 36 paired invaded and non‐invaded sample plots, invaded by the plant Antigonon leptopus, with half of these pairs located in natural and the other half in developed land‐use types on the Caribbean island of St. Eustatius. We used several taxonomic and functional variables to describe community composition and diversity. Our results show that both urban development and A. leptopus invasion affected community composition, albeit in different ways. Development significantly increased species richness and exponential Shannon diversity, while invasion had no effect on these variables. However, invasion significantly increased arthropod abundance and caused biotic homogenization. Specifically, uninvaded arthropod communities were distinctly different in species composition between developed and natural sites, while they became undistinguishable after A. leptopus invasion. Moreover, functional variables were significantly affected by species invasion, but not by urban development. Invaded communities had higher community‐weighted mean body size and the feeding guild composition of invaded arthropod communities was characterized by the exceptional numbers of nectarivores, herbivores, and detritivores. With the exception of species richness and exponential Shannon diversity, invasion influenced four out of six response variables to a greater degree than urban development did. Hence, we can conclude that species invasion is not just a passenger of urban development but also a driver of change.