Three new species of braconid wasps from Costa Rica are described here: Allorhogas crinitus reared from leaf galls on Protium panamense (Burseraceae), Allorhogas lacuna reared from galls on Melastomataceae and Allorhogas triopsis reared from fruit galls on Psychotria (Rubiaceae). These new species are diagnosed and compared with other species in the genus. These are the first records of an Allorhogas species associated with the plant families Burseraceae and Rubiaceae. It is the third association of Allorhogas with the family Melastomaceae.

Immature stages of five species of Gerridae are described and illustrated for the first time: Rheumatobates longisetosus Polhemus & Manzano, Rheumatobates probolicornis Polhemus & Manzano, Rheumatobates peculiaris Polhemus & Spangler, Telmatometra whitei Bergroth and Telmatometroides rozeboomi (Drake & Harris). The first two were distributed in the Pacific region of Colombia, R. peculiaris distributed along the Pacific region of Colombia to Ecuador, T. whitei distributed from Mexico to Colombia and Ecuador, T. rozeboomi from Central America to Colombia and Ecuador. The five species were collected in the southwest of Colombia, near the Pacific coast.

Short and long dry spells occur throughout the year and limit the access of gravid mosquitoes to oviposition sites. Using simulations in laboratory conditions, we explored the possible consequences of a long duration of egg retention on reproductive capacity, trophic behaviour, life expectancy and gonotrophic cycle in a context of breeding-site absence. KISUMU and wild gravid females of Anopheles gambiae were subjected to a delay in egg-laying following the preset modalities as immediate egg-laying versus retention for 5, 10 and 15 days. The egg batch size and the hatching rate were measured. In addition, blood-feeding patterns and life expectancy were investigated. Our study showed that oviposition occurs much faster in the standard susceptible laboratory strain An. gambiae KISUMU with a lapse of 2.2 days than in the wild females of An. gambiae with an average of 5 days between the second blood meal and egg-laying. In this experiment, the egg-retention time did not significantly affect the number of eggs laid. In the absence of breeding sites, the rate of egg-hatching decreased in proportion as the retention time became longer. The study also showed that gravid females deprived of oviposition sites continue to take blood meals. The average longevity of non-gravid females was estimated to be lower than that of gravid females. The oviposition-site deprivation has no impact on female fecundity and blood feeding, but influences egg-hatching.

The purification and characterization of rhodanese, an enzyme that catalyses the detoxification of cyanide, from the gut of the variegated grasshopper (Zonocerus variegatus L.) were carried out to understand the biochemical basis of the survival of this grasshopper living on cyanogenic plants such as cassava. All experiments, including enzyme assay, were carried out at room temperature and all buffers contained 10 mm sodium thiosulphate to stabilize the enzyme. Grasshoppers were caught alive from a cassava farm within the locality and kept frozen until analysis. Each grasshopper was dissected and the gut was removed quickly. Approximately 102 g of the gut were homogenized in three volumes of 0.1 m acetate glycine buffer (pH 7.8) containing ɛ-amino-n-caproic acid. The supernatant was collected by centrifugation at 12,000 rpm, for 30 min at 40 °C. The enzyme was purified to homogeneity by a combination of procedures such as ammonium sulphate precipitation, ion-exchange chromatography (CM-Sephadex and DEAE-Sephadex), gel filtration (Sephadex G-75) and Agarose-Blue affinity chromatography. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS–PAGE) and non-SDS–PAGE were used to ascertain the purity of the enzyme. The native and subunit molecular weights of the enzyme were determined by gel filtration on a Bio-Gel P-200 column and SDS–PAGE, respectively. Kinetic parameters were determined by using varying concentrations of one of the substrates at a fixed concentration of the other, and vice versa. Furthermore, the effects of temperature, pH and cations on the activity of the enzyme were investigated. The purified enzyme had a specific activity of 51.7 μmol thiocyanate formed/ml/min/mg protein (U/mg protein) with a yield of about 29%. The apparent molecular weight of the enzyme estimated by Sephadex G-75 gel filtration was 35,400 ± 482 Da and its subunit molecular weight determined by SDS–PAGE was 33,000 ± 212 Da. The Km values of KCN and Na2S2O3 were found to be 29.63 ± 02.87 and 26 ± 03.04 mm, respectively. An optimum pH and temperature of 7.0 and 35 °C, respectively, were obtained for the enzyme. The results of enzyme inhibition showed that the activity of the enzyme was not affected by NH4Cl, MgCl2, CoCl2, CaCl2, MnCl2, NiCl2 and SnCl2, but inhibited by ZnCl2 and BaCl2. In conclusion, these results suggest that the survival of Z. variegatus depends on the presence of the enzyme rhodanese, which shows high activity and has suitable kinetic properties in the gut of the grasshopper that feeds mainly on cassava leaves which are cyanogenic.

Bemisia tabaci Gennadius is a major pest on cotton and vegetable plants in Africa. It is considered as a cryptic species complex. Identification of the most damaging species such as the Middle East–Asia Minor 1 (B biotype) and Mediterranean (MED) (which contains the Q and Africa silverleaf (ASL) biotypes) species represents an important step towards the management of B. tabaci. Some data on the geographical distribution of the B. tabaci species complex exist in Burkina Faso, Benin and Togo, but data on the pest's invasion and displacement dynamics, in relation to time, are lacking. Here, molecular markers (mitochondrial cytochrome oxidase, mtCO1) were used to determine the identity of B. tabaci. Our results illustrate population dynamics on cotton and vegetable plants between 2007, 2009 and 2010. On cotton in southern Togo, ASL was predominant and found in sympatry with Q1. Its frequency decreased slightly over time, i.e. from 92% in 2009 to 90% in 2010. In Burkina Faso, Q1, Q3 and ASL biotypes showed different temporal and spatial distribution patterns. There, Q1 dominated on cotton plants throughout the study. This work provides relevant information about the population dynamics of B. tabaci MED species in two West African countries, Burkina Faso and Togo, in connection with pest management programmes.

Dengue has become the fastest-growing mosquito-borne disease in Sri Lanka and the control of the vectors, Aedes aegypti Linnaeus and Ae. albopictus Skuse, is the most effective way of controlling the disease. A detailed study on vector prevalence has not been recorded from Sri Lanka. Therefore, the present study was undertaken to study the prevalence of both vectors in four semi-urban study sites in two of the most affected districts, namely Kandy (wet zone) and Kurunegala (intermediate zone), by conducting egg surveys (using ovitraps) and larval surveys from June 2007 to May 2008. A total of 82,524 eggs and 2658 larvae of Ae. aegypti and Ae. albopictus were collected. A total of 3699 potential breeding habitats were examined. Ovitrap and larval indices (house, container and Breteau) showed that all four areas are at epidemic risk, especially due to a high abundance of Ae. albopictus. The highest numbers for both the species were from the Kandy sites where dense vegetation, high rainfall and low temperature prevailed. The results showed a high mortality rate during the egg-to-larva transition, suggesting that conducting an egg survey alone would overestimate the vector abundance and the disease risk. For Ae. albopictus, the monthly mean number of eggs showed positive relationships with relative humidity in both districts and with rainfall in the Kandy District. The number of dengue cases in the area had no positive relationships with the abundance of eggs or larval density indices. Discarded receptacles were the most preferred breeding habitat for these dengue vectors. Since the attractiveness (inferred by the calculated risk factors) of most of the breeding habitats was very high, elimination of these breeding sites is essential for the success of dengue control programmes.

Seasonal fluctuations of the Simulium damnosum Theobald complex and the prevalence of Onchocerca volvulus Bickel in blackflies caught in river systems bordering the Nigeria–Benin border were assessed for their direct impact on the epidemiology of onchocerciasis in South-western Nigeria. Entomological evaluation and heteroduplex assay (HDA) techniques were performed on flies caught in the eight capture points in the Ogun and Yewa river systems between October and December 2007, July and December 2008 and May and December 2009. A total of 5789 blackflies were caught on human bait, of which 727 (12.6%) flies were captured in 2007, 1723 (29.8%) in 2008 and 3339 (57.6%) in 2009. The majority of flies caught during the study were forest flies representing 90.3% of the total catch while savanna flies constituted 9.7%. Proportions of parous to nulliparous flies were low in all the catching points (31.1 and 68.9%, respectively). Of the 5789 flies dissected, 11 (0.2%) flies were infected with Onchocerca parasites with nine of the infected flies having L3 head parasites. The HDA results revealed that the Beffa form of S. soubrense was the dominant cytospecies present (87.1%) in all the capture sites when compared with 12.9% of S. damnosum s.s. The low level of infectivity of flies may therefore indicate a low transmission level of onchocerciasis in the communities along the Ogun and Yewa river systems. However, there is a need for constant surveillance on species composition and fly infectivity in the river systems along the borders of Nigeria–Benin Republic.

Hyposidra talaca (Walker) is a recent host range-expanded major insect pest of tea in Northeastern India. We studied the egg-laying pattern of H. talaca in tea plantations with an aim to take suitable measures to disrupt egg hatching and to manage the pest. Egg clutch distribution in different heights (0–8 m) of 49 shade trees of seven species was studied. Stems and foliage of a total of 400 tea plants growing close to the shade trees were also subjected to the survey. Female moths deposited eggs underneath the scales of shade tree bark, lichen cover and the root mantles of parasitic plants that are growing on all shade tree plants, except Melia azaderach L. The shade tree bark of M. azaderach and tea plants had no egg deposits. Overall, 1785 egg clutches, comprising 84–302 eggs/clutch (average 258 eggs), were located. An average of 45.77 ( ± 7.06 SD, range 0–183) egg clutches was found per tree. The mean number of egg clutches was high in Acacia lenticularis Buch.-Ham. (95.4 ± 24.78 SD, range 40–183), and was low in Lagerstroemia speciosa (L.) Pers. (23 ± 6.42 SD, range 4–46). Overall, the number of egg clutches reduced with the height of shade trees. This study suggests that the oviposition of H. talaca is typical for an outbreak species and that the management of shade trees, including the choice of species, has an important role in controlling the pest in tea plantations.

The present study surveyed adult caddisflies in Ile-Ife to identify the species that contribute to the fauna of freshwater ecosystems of this area and to determine their seasonal abundance. Adult caddisflies were collected between June 2009 and November 2010 from eight sampling stations established at different locations using an improvised light trap. A total of 754 adult caddisflies that were collected represent six species in six genera and three families. The species identified are Dipseudopsis conformis Navas, 1931, Polymorphanisussimilis Ulmer, 1912, Aethaloptera dispar Brauer, 1875, Ceraclea njalaensis (Mosely, 1933), Pseudoneureclipsis mlangensis Mosely, 1939 and Cheumatopsyche digitata (Mosely, 1935). The Hydropsychidae was represented by three species belonging to three genera. The hydropsychid C. digitata was the dominant and most widely distributed species, occurring at all sampling stations with the highest frequency of occurrence (51%). On the other hand, P. mlangensis (Dipseudopsidae) was the least abundant with the lowest frequency of occurrence (0.8%).

With the advent of transgenic Bacillus thuringiensis (Bt)-cowpea, there is a need to identify the feeding preferences of Maruca vitrata Fab. to determine in which component of the plant the expression of the toxin needs to be the highest to ensure the greatest efficacy of insecticidal Bt proteins. In the current study, we examined the feeding preferences of M. vitrata larvae in a naturally infested cowpea field. We also tested, in the laboratory, the suitability of different flower components for the larval development of M. vitrata. Our results indicate that in the field, all types of flowers, regardless of their age, were infested with M. vitrata larvae. The reproductive organs, in the flowers, were the preferred feeding diet for the larvae. Laboratory bioassays confirmed that the reproductive organs were the optimal tissues for M. vitrata larval development. The implications of these findings for transgenic Bt-cowpea are discussed.

The sugarcane aphid Melanaphis sacchari (Zehnt.) has become a serious pest of sorghum, particularly during the post-rainy season in India and East and Southern Africa. Therefore, we tested a number of techniques to screen sorghum genotypes for their resistance to M. sacchari. Infesting the plants with aphid-infested leaf cuttings and covering with a nylon net was effective in screening sorghum genotypes for their resistance to M. sacchari. Sprinkling the plants with aphids (filled in an 0.5 ml eppendorf tube) in the greenhouse was also used to confirm whether the resistance of genotypes selected is less susceptible to the aphids under natural infestation. Nine genotypes (Line 61510, ICSV 12001, ICSV 12002, ICSV 12003, ICSV 12004, ICSV 12005, SLR 41, PU 10-1 and DJ 6514) exhibited moderate levels of resistance to M. sacchari. These genotypes also exhibited a lower rate of aphid multiplication in the clip cage and leaf disc assays. The rates of aphid multiplication were lower on the genotypes IS 21807, IS 40615, IS 40616 and IS 40618 than on the susceptible check, Swarna in the clip cage assay under the field conditions. Also, lower rates of aphid increase were also recorded on IS 21807 and IS 40615 in the leaf disc assay under laboratory conditions. Some of the genotypes that exhibited resistance to aphid damage under field conditions showed comparatively higher rates of aphid increase than the susceptible check, Swarna in the clip cage assay, indicating that antixenosis could be one of the components of resistance to M. sacchari in these genotypes. Therefore, the clip cage assay could be used to gain further understanding of the mechanisms of resistance to M. sacchari. There is a need to assess the role of antixenosis and colonization in genotypic reaction against M. sacchari to identify the lines with different mechanisms of resistance to this pest. The results suggested that the nylon net technique could be used to screen sorghum genotypes for resistance to M. sacchari. The genotypes exhibiting resistance to M. sacchari can be used to develop aphid-resistant sorghums for sustainable crop production.

The demographic attributes of the parthenium beetle Zygogramma bicolorata Pallister were studied using Parthenium hysterophorus L. as food under different abiotic and biotic variables. Intrinsic and finite rates of increase were highest with the shortest mean generation and doubling times when Z. bicolorata was fed on inflorescences followed by the leaves and stems of P. hysterophorus. Temperature significantly affected the demographic parameters. The net reproductive rate was highest at 27 °C and lowest at 35 °C. Different photoperiodic exposures altered the demographic attributes of the beetles with long-day exposure (14L:10D) resulting in optimal values compared with other photoperiodic exposures. Continuous darkness (0L:24D) and continuous light (24L:0D) suboptimally affected the demographic attributes of the beetles. In response to the light of different wavelengths, the net reproductive rate, and intrinsic and finite rates of increase were significantly higher when the beetles were reared under a broad spectrum of white light followed by those under ~570 nm (yellow), ~475 nm (blue) and ~650 nm (red). Information gained in this study may be helpful in the mass multiplication of Z. bicolorata, and thereby strengthening the biocontrol of parthenium weed.

Indian siris, Albizia lebbeck (L.) Benth., is a useful tree that is being widely planted for shade in the Ahwaz region of southwest Iran. The tree is, however, severely attacked by the citrus red mite Eutetranychus orientalis Klein. Seasonal population dynamics of the mite were investigated on A. lebbeck in Ahwaz during 2010–2011. Eutetranychus orientalis had two population peaks on A. lebbeck. The first and second activity periods were observed from 10 August to 28 October 2010 and 24 February to 20 June 2011, respectively. The highest density and activity of E. orientalis was observed during September to November and April to May. During these months, the average temperature and relative humidity were 20–35 °C and 21–40%, respectively. The spatial distribution of the mite was evaluated using the parameters of Taylor's power law, which revealed an aggregated spatial distribution of E. orientalis on A. lebbeck. The results of the study could be applied to develop an integrated pest management programme against the pest.

Pestalotiopsis is a disease that causes damage to the leaves of Elaeis guineensis Jacquin and defoliation in commercial plantations. Lepidoptera larvae are the main insects that spread the disease. The aim of this paper is to report for the first time the insects found in oil palm plantations in Colombia. Lepidoptera larvae were collected from cultures in the presence of Pestalotiopsis and were identified to species level. Severity and duration of the symptoms of Pestalotiopsis were evaluated from the damage caused by the insects of each species. Eighteen species of the families Dalceridae (one), Elachistidae (four), Limacodidae (eight), Megalopygidae (two), Nymphalidae (one), Psychidae (one) and Saturniidae (one) confirmed assistance and disease transmission. Increased severity of Pestalotiopsis damage was induced by Acharia hyperoche, Acraga ochracea, Durrantia arcanella, Euclea diversa, Euprosterna elaeasa and Stenoma impressella. The development of Pestalotiopsis on the leaves of E. guineensis and its symptoms were observed between 16.8 and 72.9 days. The damage caused by these insects on the leaves of E. guineensis was the main entrance of the virulent fungal spores. The results of this study contribute to the knowledge of Lepidoptera that attend and spread the Pestalotiopsis fungus on leaves in oil palm plantations. To our knowledge, no previous records of this disease on the plant are found in Colombia.

Little is known about the efficacy of sampling methods for monitoring bee communities in agricultural landscapes in sub-Saharan Africa, in general, and in Uganda, in particular. To provide baseline information on the effectiveness of different sampling methods, 26 sites with varying landscape characteristics were sampled in 2006 in agricultural landscapes in Uganda. Bees were sampled using line transect count, coloured pan trap and hand net methods. In total, 80,883 bee individuals were collected. Totals of 59, 314 and 559 bee species were recorded in transect counts, pan traps and hand nets, respectively. Thus hand nets captured the most species overall. There were few species that overlapped across the three sampling methods. Wild bees were significantly more abundant in yellow pan traps than in blue or white ones. In contrast, bee species richness was significantly higher in blue pan traps than in white or yellow pan traps. Overall, pan-trapping was found to be a complementary method to hand-netting for monitoring bee communities in Uganda.

The present study aimed to determine the selectivity of the pyrethroid lambdacyhalothrin on arthropod natural enemy populations in irrigated rice fields in Rio Grande do Sul, Brazil. The study was conducted at three sites: districts of Cachoeira do Sul, Eldorado do Sul and Capivari do Sul during the crop years of 2007/2008 and 2008/2009. Each site consisted of two subareas divided into four plots. One of the subareas received a spray application of 150 ml/ha of lambdacyhalothrin CS 50, while the other subarea was untreated. Arthropods were collected at 2, 15, 30 and 45 days after the application of the insecticide to assess its impact on natural enemy populations. The results indicated consistent differences in natural enemy populations between the treated and untreated areas, especially within the first 2 weeks after the application of the insecticide. Principal components analysis together with χ2 analysis revealed differences in the populations of Tetragnathidae, Anyphaenidae, Araneidae, Coccinellidae, Phytoseiidae and Coenagrionidae between the treated and untreated areas. This study indicated the existence of a great diversity of arthropod natural enemies in irrigated rice fields in a subtropical environment similar to that reported previously from rice fields in tropical environments. In addition, lambdacyhalothrin was shown to be a rapid acting insecticide, with a significant initial decrease in natural enemy populations followed by a rapid recovery beginning at 2 weeks after the application of the insecticide. Especially disconcerting is the severe impact of the insecticide on Phytoseiidae and Araneidae, which are considered key natural enemies for the management of rice pests in southern Brazil.

In the present study, we aimed to assess the suitability of predatory parameters, namely voracity, consumption index, conversion efficiency and growth rate, as measures of prey suitability. For this purpose, fourth-instar larvae and 10-day-old adult females of four co-occurring ladybirds, namely Coccinella septempunctata (L.) (C7), C. transversalis F., Cheilomenes sexmaculata (F.) and Propylea dissecta (Mulsant), fed on two essential species of aphid prey, Aphis craccivora Koch and Lipaphis erysimi (Kaltenbach), were observed. The results revealed that, with the exception of C7, the other three ladybirds performed better on A. craccivora. Previous studies based on reproductive and developmental attributes have also shown that A. craccivora is a more suitable prey for these three ladybirds, indicating a strong correlation and affirming the viability of using these measures as a mark of prey suitability. In a similar manner, fourth instars and adult females of C7 performed better on L. erysimi over A. craccivora. This detectable difference in consumption and utilization of aphid prey species by the four ladybirds indicates that these predatory parameters can be used as tools for assessing prey suitability in ladybirds.

Oomyzus sokolowskii (Kurdjumov) is a gregarious larval–pupal parasitoid of the diamondback moth Plutella xylostella (L.). The objective of this study was to investigate the interactions between host and parasitoid by examining the effects of biotic factors such as gregariousness, host origin and stages, and female parasitoid age on the parasitism rate, developmental time, the number of offspring and the offspring sex ratio of O. sokolowskii under laboratory conditions. The percentage of parasitism and the number of parasitoids increased with the number of O. sokolowskii females. Oomyzus sokolowskii preferred fourth larval instars over other larval stages. The parasitism rate and the progeny production of O. sokolowskii decreased with parasitoid age; however, the developmental time and the sex ratio of the offspring were not significantly different. Our results confirm previous findings on larval preferences of O. sokolowskii. The study also confirmed the importance of geographical origin of the host on the performance of O. sokolowskii.

In the present study, four methods of rice crop establishment, viz. conventional transplantation, bed transplantation (BT), furrow transplantation (FT) and puddled direct seeding (PDS), were evaluated during two wet seasons to determine their influence on the incidence of insect pests and grain yield. Observations were recorded starting from 40 days after transplanting (DAT) and seeding (DAS) to 110 DAT and DAS. The interaction between crop establishment methods and observation days was significant in the case of folded leaves by Cnaphalocrocis medinalis (Guenée), deadhearts by Scirpophaga incertulas (Walker) and the Sogatella furcifera (Horvath) population. The number of folded leaves in the bed-transplanted crop (8.87%) and puddle direct seeded crop (10.62%) was significantly higher than that in crop grown using the other crop establishment methods. The incidence of deadheart damage was significantly higher in the PDS plots (5.85%), while that of whitehead damage was higher in the BT (5.89%) and PDS (6.54%) plots than in the plots managed by the other methods. The S. furcifera population build-up was significantly higher in the FT (1.98 hoppers/hill) and PDS (2.24 hoppers/hill) plots than in the plots managed by the other crop establishment methods. Paddy yield was significantly higher in the conventionally transplanted crops followed by the furrow- and bed-transplanted crops.