Insects associated with tropical foliage produced in the coffee growing region of Colombia

We conducted a survey of insects and pest management practices on 34 farms growing ornamental tropical foliage plants in the central coffee region of Colombia over two years. Tropical foliage provided habitat for a diverse range of insects. In total, phytophagous or detritivorous insects from six orders, 40 families and 62 genera were collected. The most common were Hemiptera (29 genera from 16 families), followed by Coleoptera (17 genera from 4 families), Diptera (5 genera from 5 families), Lepidoptera (5 genera from 4 families), Hymenoptera (3 genera from 2 families) and Orthoptera (2 genera from 2 families). The most common phytophagous species were leaf cutting ants (Atta and Acromyrmex spp.), leaf beetles (Chrysomelidae), leafhoppers (Cicadellidae), stinkbugs (Pentatomidae), squash bugs (Coreidae), tree hoppers (Membracidae) and plant hoppers (Fulgoridae). Beneficial insects identified from tropical foliage included predators and parasitoids amongst 5 orders, 12 families and 22 genera. The most abundant were predators among the Coccinellidae, Chrysopidae, Reduviidae, Lycidae and Formicidae but only low numbers of parasitoids (Ichneumonidae, Braconidae and Tachinidae) were collected. A pest management questionnaire given to growers revealed a preponderance of reliance on broad spectrum insecticides with a smaller number of growers (approximately one third) also using some biological control methods. Our survey contributes basic information regarding diversity of Neotropical insects associated with ornamental foliage plants.

Perspectives of digestive pest control with proteinase inhibitors that mainly affect the trypsin-like activity of Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae)

The present study describes the main characteristics of the proteolytic activities of the velvetbean caterpillar, Anticarsia gemmatalis Hübner, and their sensitivity to proteinase inhibitors and activators. Midguts of last instar larvae reared on an artificial diet were homogenized in 0.15 M NaCl and centrifuged at 14,000 g for 10 min at 4ºC and the supernatants were used in enzymatic assays at 30ºC, pH 10.0. Basal total proteolytic activity (azocasein hydrolysis) was 1.14 ± 0.15 absorbance variation min-1 mg protein-1, at 420 nm; basal trypsin-like activity (N-benzoyl-L-arginine-p-nitroanilide, BApNA, hydrolysis) was 0.217 ± 0.02 mmol p-nitroaniline min-1 mg protein-1. The maximum proteolytic activities were observed at pH 10.5 using azocasein and at pH 10.0 using BApNA, this pH being identical to the midgut pH of 10.0. The maximum trypsin-like activity occurred at 50ºC, a temperature that reduces enzyme stability to 80 and 60% of the original, when pre-incubated for 5 and 30 min, respectively. Phenylmethylsulfonyl fluoride inhibited the proteolytic activities with an IC50 of 0.39 mM for azocasein hydrolysis and of 1.35 mM for BApNA hydrolysis. Benzamidine inhibited the hydrolysis with an IC50 of 0.69 and 0.076 mM for azocasein and BApNA, respectively. The absence of cysteine-proteinases is indicated by the fact that 2-mercaptoethanol and L-cysteine did not increase the rate of azocasein hydrolysis. These results demonstrate the presence of serine-proteinases and the predominance of trypsin-like activity in the midgut of Lepidoptera insects, now also detected in A. gemmatalis, and suggest this enzyme as a major target for pest control based on disruption of protein metabolism using proteinase inhibitors.

Indirect effect of neem oil on Podisus nigrispinus (Hemiptera, Pentatomidae): biology and predatory capacity

This study evaluated the effects on the development and predatory capacity of Podisus nigrispinus fed on Spodoptera frugiperda that have ingested different concentrations of neem oil. The predatory capacity of Podisus nigrispinus was assessed, separating nymphs (fourth instar) and adults (males and females). The treatments consisted of S. frugiperda larvae reared in neem oil aqueous solutions (0.077, 0.359 and 0.599%), deltamethrin EC 25 (0.100%) and control arranged in a completely randomized design, with ten replicates. Insects were offered three larval densities (one, three and six), in the third or fourth instars. The predated larvae were examined at 24 and 48 hours after the beginning of the experiment. Biological parameters of Podisus nigrispinus were evaluated in groups of ten second-instar nymphs transferred to pots, in five replicates. Insects were offered 2-6 third and/or fourth-instar larvae reared in the same neem oil concentrations in a completely randomized design. The following parameters were evaluated: duration of each nymph stage (days), nymph mortality (%), weight of fifth-instar nymphs (mg), sex ratio, weight of males and females (mg) and longevity of unfed adults (days). The predatory capacity of nymphs and adults of Podisus nigrispinus was influenced by the neem oil at the concentrations of 0.359% and 0.599% in the highest density. The concentration of 0.359% lengthened the nymphal stage and the concentration of 0.599% reduced the weight of males.

Non-biting flying insects as carriers of pathogenic bacteria in a Brazilian hospital

IntroductionInsects have been described as mechanical vectors of nosocomial infections.MethodsNon-biting flying insects were collected inside a pediatric ward and neonatal-intensive care unit (ICU) of a Brazilian tertiary hospital.ResultsMost (86.4%) of them were found to carry one or more species of bacteria on their external surfaces. The bacteria isolated were Gram-positive bacilli (68.2%) or cocci (40.9%), and Gram-negative bacilli (18.2%).ConclusionsInsects collected inside a hospital were carrying pathogenic bacteria; therefore, one must consider the possibility they may act as mechanical vectors of infections, in especially for debilitated or immune-compromised patients in the hospital environments where the insects were collected.

Evidence for a stress hypothesis: hemiparasitism effect on the colonization of Alchornea castaneaefolia A. Juss.uphorbiaceae) by Galling Insects

Stressed plants are generally more attacked by galling insects. In this study we investigated the relationship between population abundance and species richness of galling insects on the tree Alchornea castaneaefolia A. JUSS. (Euphorbiaceae), submited to stress induced by the hemiparasite Psittacanthus sp. (Loranthaceae) in the Amazon, Brazil. Branches of A. castaneaefolia attacked by the hemiparasite were more heavily infested by galling insects than non-attacked branches. The field observations partially corroborate the hypothesis that there would be an optimal level of host-plant stress for galling insect establishment.

Toxicity and repellency of essential oils to Zabrotes subfasciatus (Boheman) (Coleoptera, Chrysomelidae, Bruchinae) in Phaseolus vulgaris L

The effects of tangerine (Phaseolus vulgaris Blanco), lemon (Citrus medica limonum Lush), pear orange (Citrus sinensis L. Osbeck), red copaiba (Copaifera langsdorffii Desf.), rosemary (Baccharis dracunculifolia De Candole), Eucalyptus (Eucalyptus globulus Labillardière and E. citriodora Hook), lemongrass (Cymbopogon citratus Stapf.) and citronella (Cimbopogon nardus Linnaeus) oils at several concentrations on Zabrotes subfasciatus (Boheman) were studied. In toxicity tests, grains of Phaseolus vulgaris L. cv. Rajadinho were impregnated with oils and infested with adults of Z. subfasciatus up to 24 hours old. All tested oils were effective in reducing the viable egg-laying and adult emergence of this pest, in function of the concentrations used, highlighting E. citriodora and E. globulus oils which caused 100% effectiveness from 0.5 mL Kg-1 concentration. In repellency tests, two arenas consisting of plastic containers, connected symmetrically to a central box by two plastic tubes were used. In one of the boxes, untreated beans were placed and on the other ones beans treated with each oil concentration were used. In the central box, five couples of Z. subfasciatus were released. Grains of P. vulgaris treated with oils of E. citriodora, C. citratus and C. oleifera reduced the attraction percentage of Z. subfasciatus adults, while the E. globulus increased this percentage. The percentages of reduced viable eggs ranged from 17.9% (C. medica limonum) to 93.3% (C. nardus), while the reduction on the number of emerged insects was 23.9% and 95.9%, respectively for these same oils.

Sôbre os inimigos naturais da lagarta das palmáceas Brassolis sophorae sophorae (L.) (Lep., Brassolidae)

Brassolis sophorae (L.) (Lep., Brassolidae) is an old and important pest of some Brazilian Palmae, among which Cocos nucifera L. and Copemicia cerifera Mart, are the most valuable economically. Eggs are attacked by Anastatus reduvii (Howard) (Eupel-midae) and Telenomus sp. and Telenomus nigrocoxdlis Ashmead (Scelionidae), the larvae being destroyed by Withemia pinguis (F.) (Tachinidae). Six other insects devellop inside the pupae : Xanthozona melanopyga (Wiedmann) and Belvosia sp. (Tachinidae) and the Hymenoptera Brachymeria annulata (F.), B. incerta (Cres-son), Spilochalcis nigrifrons Cameron and S. morleyi Ashmead (Chalcicidae), the last of them being principally treated in this paper. A species of Sarcophagidae (Sarcophaga lambens Wiedmann) was also noted, some flies being gotten from a single pupa. In Piracicaba (State of S. Paulo, Brasil), according to the Author's observations, B. sophorae principal enemy is X. melanopyga, to which our attention has to be directed in a biological fight against the mentioned Brassolidae. The reported Telenomus sp. is also very harmful to B. sophorae eggs. In the whole zone of its distribution, the hosts of B. sophorae caterpillars are Palmae plants, appearing sporadically feeding on banana and sugar cane leaves.

Contribuição para o conhecimento da Mimosicerya hempeli (Cockerell, 1899) (Homoptera. Margarodidae) e de seu predador Exoplectra erythrogasfer Mulsant, 1851 (Coleoptera, Coccinellidae)

This paper deals with Mimosicerya hempeli (Cock., 1899) (Homoptera, Margarodidae) and its predator, the ladybeetle Exo-plectra erythrogaster Muls., 1851 (Coleoptews, Coccinellidae), which were found to occur at Piracicaba, State of São Paulo, Brasil. The first is a pest of "cássia imperial" (Cassia fistula L.), and several other trees. As those insects are little known, a few bionomical notes and descriptions of some of their stages are presented. The adult scales proved to be very resistant to an application of mineral oil plus malathion. Methyl Demeton applied with irrigation water showed no control. The same insecticide injected into the trunk gave very poor results.

The influence of prior experience with artificial fruits on the ovipositioning behavior of Anastrepha fraterculus (Diptera, Tephritidae)

The South American fruit fly, Anastrepha fraterculus (Wiedemann, 1830) (Diptera, Tephritidae), is a leading pest of Brazilian fruit crops. This study evaluated how prior experience with artificial fruits containing peach and/or guabiroba pulp influenced the ovipositing behavior of A. fraterculus. Insects 15-21 days old were exposed to four treatments: 1) experience with guabiroba, Campomanesia xanthocarpa O. Berg (Myrtaceae); 2) experience with peach, Prunus persica (L.) Batsch (Chimarrita cultivar; Rosaceae); 3) experience with both fruits; and 4) no experience (naive). Naive females and females experienced with guabiroba pulp and with both fruits (peach and guabiroba) oviposited and showed dragging and puncturing behavior on substrates containing guabiroba, but females that were only exposed to peach pulp did not show a preference for any substrate. The study shows that prior experience with substrate influences ovipositing behavior in A. fraterculus.

The evolution of purinergic receptors involved in recognition of a blood meal by hematophagous insects

Many blood feeders use adenine nucleotides as cues for locating blood meal. Structure-activity relationship of adenine nucleotides as phagostimulants varies between closely-related species of blood feeders. It is suggested that a preexisting diverse pool of nucleotide-binding proteins present in all living cells, serves as a source of receptor proteins for the gustatory receptors involved in blood detection. It is proposed that the selection of any such nucleotide-binding protein is random.

Vitellogenesis in insects and other groups: a review

The eggs from oviparous organisms contain large amounts of vitellus, or yolk, wich are utilized by the growing embryo. Vitellogenesis is the process of vitellus accumulation and involves massive heterosynthetic synthesis of the protein vitellogenin (Vg) and its deposition in the oocyte. This work summarizes data on Vg structure, synthesis, uptake by oocytes and its fate during embryogenesis. The hormonal control of vitellogenesis and its tissue, sex and temporal regulation are also discussed. Where it is available, data on structure and expression of Vg-coding genes are reviewed. Insect vitellogenesis is priorized although other oviparous animal groups outside insects are also treated.