The actographic examination of flight activity of the cocoa mirid Distantiella theobroma (Hemiptera: Miridae)

The patterns of flight activity of adult Distantiella theobroma were recorded in an actograph placed in the field. Flight activity of virgin females showed a non-linear increase with age, was highest around mid-day and related to sex attraction behaviour. Mated females and males both showed sharp peaks of activity in the late afternoons. Male flight was depressed by low light intensities and all activity declined with falling light intensity in the evenings and ceased entirely during the hours of darkness.

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Résumé Un appareil a été conçu pour enregistrer l'activité de vol dans les conditions naturelles et a été utilisé pour étudier le comportement des mâles et des femelles de D. theobroma, aux diverses phases de leur vie imaginale.L'activité de vol de D. theobroma eest exclusivement diurne. Les femelles restent relativement inactives pendant les premiers trois jours de leur vie imaginale. Après le début de maturité et bien que non encore accouplées, on note un accroissement de leur activité qui est maximum vers le milieu du jour, mais s'atténue pendant la fin de l'après-midi, alors qu'elles manifestent un comportement d'appel et se révèlent attractives pour les mâles.Les femelles qui se sont accouplées montrent un début d'activité tôt le matin et qui s'accroît pour atteindre un pic bien marqué en fin de l'après-midi, pour décliner ensuite avec la baisse de l'intensité lumineuse. L'activité des mâles commence plus tard et atteint son maximum vers 16h30. Ceci coïncide avec le moment où le plus grand nombre de femelles manifestent un comportement d'appel. Le vol des mâles n'apparaît qu'au-dessus d'un certain seuil d'intensité lumineuse et est inhibé par la pluie.Le changement avec l'âge de l'activité des femelles vierges présente des modalités caractéristiques qui se révèlent concorder avec les variations du nombre de mâles attirés par les femelles vierges de différents âges.

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This work was done as part of the programme of the International Capsid Research Team which was sponsored by the International Office of Cocoa and Chocolate.     

The resistance pattern in a strain of the cocoa capsid (Distantiella theobroma (Dist.)) resistant to BHC

Summary BHC-resistance in the cocoa capsid,Distantiella theobroma, in Ghana was confirmed, and cross resistance found to extend to six other chlorinated hydrocarbons including Thiodan. There was no cross resistance to DDT, Sevin or to the organophosphorus compounds tested.

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Zusammenfassung Die BHC-Resistenz eines Stammes von Kakaowanzen (Distantiella theobroma), der in der Umgebung der Kakao-Versuchsanstalt in Pankese, Ghana, gefunden wurde, wird durch Vergleich mit einem normal empfindlichen Stamm aus New Tafo, Ghana, nachgewiesen. Die Resistenz erstreckt sich auch auf Endrin, Dieldrin, Aldrin, Heptachlor, Chlordan und Thiodan. Bei letzterem was sie besonders hoch, obwohl dieses Mittel in Ghana bisher noch nicht in Anpflanzungen angewandet wurde. Gegenüber DDT war der BHC-resistente Stamm etwas empfindlicher als der normale Stamm aus New Tafo, beide Stämme waren jedoch sehr tolerant gegenüber diesem Insektizid. Gegen Sevin waren beide Stämme gleichmäßig empfindlich. Gegen die organischen Phosphorverbindungen Dibrom, Diazinon, Cidial, Sumithion, Lebaycid und Malathion war keine Resistenz nachweisbar. Bevor die Resistenz auftrat, waren ungefähr 25 Generationen Feldspritzungen ausgesetzt gewesen.

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Work done whilst on secondment at the West African Cocoa Research Institute, Tafo, Ghana.     

Plant preference in the zoophytophagous generalist predator Macrolophus pygmaeus (Heteroptera: Miridae)

Macrolophus pygmaeus (Heteroptera: Miridae) is an omnivourus predator used to control several pests of horticultural greenhouses. With the aim to explore the relationship between M. pygmaeus and different host plants compared with tomato, plant preferences and bio-cycle traits were studied using: Capsicum annuum, Calendula officinalis, Salvia officinalis, Parietaria officinalis and Solanum nigrum. Species were selected among natural host crop and wild plants. Plant preference was measured by multi-choice host plant selection and olfactometric bioassays. Bio-cycle traits were assessed on reproduction and on nymphal development with and without animal diet support. Among tested plants, P. officinalis was the least attractive under laboratory conditions. Furthermore the availability of prey was crucial for the successful establishment of M. pygmaeus on tested plants, suggesting the inability of nymphs to complete development to adulthood on a strictly phytophagous diet. Nevertheless, M. pygmaeus seemed to prefer plants where phytophagy provides a fitness benefit.     

Density thresholds for Nesidiocoris tenuis (Heteroptera: Miridae) in tomato crops

Nesidiocoris tenuis (Reuter) (Heteroptera: Miridae) is common in vegetable crops of the Mediterranean area, with an increasing worldwide range of geographical distribution. This omnivore is a reputed predator of small arthropod pests, but also produces injuries on vegetative and reproductive plant parts. The aim was to estimate density thresholds based on N. tenuis and whitefly abundance for the management of N. tenuis in tomato crops. The assay was carried out in mesh-walled and plastic greenhouses in southern Spain during 2004 and 2007. The natural population dynamics of N. tenuis and whitefly were monitored, and impact on yield quantified. The economic injury level and intervention threshold were predicted based on the zoophytophagous response of N. tenuis and the yield compensation of tomato plants. The proportion of aborted flowers on the tomato plants was related directly to the abundance of N. tenuis and inversely to the interaction between the number of N. tenuis and the number of whitefly immatures. Over-compensation of fruit weight was predicted for flower abortion rates due to N. tenuis lower than 0.171. No yield reduction is expected for values <0.65 N. tenuis per leaf, independent of the whitefly abundance, nor for up to 5 N. tenuis and >26 whitefly immatures per leaf. For intermediate N. tenuis levels, the outcome depends on the prey density. The probability of N. tenuis producing yield loss in tomato crops increases at N. tenuis:whitefly ratios >0.168. Yield reduction is expected after N. tenuis population peaks, when whitefly numbers have been reduced.     

Mating attraction by Stenotus rubrovittatus (Heteroptera: Miridae) females and its relationship to ovarian development

Stenotus rubrovittatus (Matsumura) (Heteroptera: Miridae) causes brown or black marks on rice, Oryza sativa L., grains (pecky rice), and it is becoming of increasing importance in Japan. Attractiveness of adult females or males of S. rubrovittatus to conspecific individuals was examined in the field in 2003 and 2004. Unmated female-baited traps captured significantly more males than did the unmated male-baited traps. However, the numbers of females captured by female- or male-baited traps were low, and they were not significantly different from the numbers caught by the control traps. No nymphs were captured by any traps. In 2004, we examined the effects of age and mating experience on female attraction ability with the goal of understanding the role of reproductive development in the observed behavior. The daily number of males captured by young unmated female (3-d-old)-baited traps increased from the first day until the fourth day of experiments, and then capture started to decrease. The peak in the number of captured males corresponded to the preoviposition period. When we observed ovarian development of S. rubrovittatus females under 25 degrees C and a photoperiod of 16:8 (L:D) h, we found that vitellogenesis had already started in approximately 30-50% of 1-d-old individuals. By the fifth day after emergence, 50-70% of individuals had mature eggs. These results indicated that the attractiveness of females is the strongest when egg laying becomes possible. Therefore, S. rubrovittatus females attract males selectively for mating, and it is probable that females use a sex pheromone for the attraction.     

Oviposition, fertility, and longevity and their relation to copulation in Antestiopsis lineaticollis (Heteroptera: Miridae)

Egg production, fertility, and longevity of solitary mated females and control pairs of males and females of Antestiopsis lineaticollis Stål. (=A. orbitalis bechuana Kirkaldy) were studied in the laboratory at 22–23° and 60–70% relative humidity. No significant differences were found in adult longevity, inter-oviposition period, number of eggs, post-reproductive period, and the number of eggs remaining in ovaries after the death of females. Control females had a significantly longer duration of oviposition than solitary ones. Thus, the physical presence of males or multiple mating by females has no influence on egg production in the Antestia bug.

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Zusammenfassung Eiproduktion, Fruchtbarkeit und Lebensdauer isolierter begatteter Weibchen sowie von Kontrollpaaren von Männchen und Weibchen von Antestiopsis lineaticollis Stål. (= A. orbitalis Kirkaldy) wurden im Labor bei 22–23° und 60–70% relativer Luftfeuchtigkeit untersucht. Es wurden keine signifikanten Unterschiede in der Lebensdauer der Adulten, den Perioden zwischen den Eischüben, der Anzahl der Eier, der Postreproduktionsperiode und der Anzahl der nach dem Tode der Weibchen in den Ovarien zurückgebliebenen Eier gefunden. Die Kontroll-Weibchen hatten eine signifikant längere Eiablagedauer als die isolierten. So hat also die physische Gegenwart der Männchen oder wiederholte Paarung der Weibchen bie der Antestia-Wanze keinen Einfluß auf die Eiproduktion.

     

First evidence of sex chromosome pre-reduction in male meiosis in the Miridae bugs (Heteroptera)

The karyotype and male meiosis of Macrolophus costalis Fieber (Insecta, Heteroptera, Miridae) were studied using C-banding, AgNOR-banding and DNA sequence specific fluorochrome staining. The chromosome formula of the species is 2n = 28(24+X1X2X3Y). Male meiotic prophase is characterized by a prominent condensation stage. At this stage, two sex chromosomes, "X" and Y are positively heteropycnotic and always appeared together, while in autosomal bivalents homologous chromosomes were aligned side by side along their entire length, that is, meiosis is achiasmatic. At metaphase I, "X" and Y form a pseudobivalent and orient to the opposite poles. At early anaphase I, the "X" chromosome disintegrates into three separate small chromosomes, X1, X2, and X3. Hence both the autosomes and sex chromosomes segregate reductionally in the first anaphase, and separate equationally in the second anaphase. This is the first evidence of sex chromosome pre-reduction in the family Miridae. Data on C-heterochromatin distribution and its composition in the chromosomes of this species are discussed.     

The food requirements of Blepharidopterus angulatus (Heteroptera: Miridae) as a predator of the lime aphid, Eucallipterus tiliae

The weight of lime aphids consumed by B. angulatus increases at an increasing rate during nymphal development, with the fifth instar contributing 50% of the total consumption. Males and females reach different adult weights, but show no difference in food consumption. The efficiency of conversion of aphid food into body tissues diminishes from the third instar onwards. Females continue to oviposit for 5 weeks at least, laying on average just over one egg per day. The daily food requirements of ovipositing adult females increase as they get older, being more than twice as great as those of fifth-instar nymphs. Nymphs can tolerate a less than optimal food supply, and in the early instars they can compensate for an inadequate diet by converting food into body tissues with increased efficiency. Teneral adult weight is, however, proportional to the weight of food consumed during the fifth instar. B. angulatus can develop successfully on parasitized aphids and can utilise honeydew to prolong survival and, to a limited degree, to increase in weight. Leaf tissue has no significant value as a source of food.

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Résumé Les besoins alimentaires de B. angulatus ont été étudiés au laboratoire à une température de 14 degrés.Quand B. angulatus est largement approvisionné avec des pucerons du tilleul, sa consommation de nourriture s'accroît de plus en plus au cours du développement, de même que son poids, de sorte que le 5ème stade larvaire absorbe un peu plus de 50% du poids total de pucerons consommés pendant toute la durée du développement larvaire. Ce 5ème stade larvaire est plus long que le 4ème, lequel est également plus long que chacun des trois premiers stades. La consommation journalière est moindre au début et à la fin de chaque stade, en particulier dans les derniers stades.Le prédateur consomme jusqu'à 90% du poids du corps de la proie. Quand les pucerons lui sont donnés en excès, la larve du 5ème stade de B. angulatus tend à tuer plus de proies qu'elle n'en consomme, ce qui sans doute est dû à la stimulation provoquée par la proie.Le rendement de croissance (efficience de la transformation du poids d'aphides absorbés en poids du corps du prédateur) diminue à partir du 3ème stade larvaire (de 46% pour le ler stade à 19% chez les adultes femelles). Au 5ème stade larvaire le rendement de croissance des mâles est significativement plus faible que celui des femelles, de sorte que les mâles sont plus légers que les femelles à l'état de maturité, bien que les deux sexes consomment le même poids de pucerons.Les femelles adultes commencent à pondre environ deux semaines après la mue imaginale et chacune dépose en moyenne 44 ufs, environ 1, 2 par jour. Les besoins alimentaires des femelles adultes en cours de ponte s'accroissent avec leur âge; leurs besoins journaliers en pucerons sont plus de deux fois aussi grands que ceux des larves du 5ème stade.Les larves peuvent supporter un apport en nourriture réduit par rapport à l'optimum.La résistance à la restriction alimentaire est plus grande au 3ème stade larvaire qu'aux ler et 5ème stades. Le ler et le 3ème stade larvaire peuvent compenser une réduction de l'apport alimentaire, par un meilleur rendement de croissance, ce que ne peuvent faire les larves du 5ème stade. B. angulatus peut se développer de façon satisfaisante en se nourrissant de pucerons parasités et momifiés. Il peut aussi utiliser le miellat en cas de disette ce qui lui permet d'accomplir un développement partiel, d'un stade au suivant, mais pas au-delà. En moyenne B. angulatus ne survit pas plus longtemps quand on ne lui offre que de l'eau ou des feuilles de tilleul, l'insecte peut en effet piquer celles-ci, pour lutter contre la dessication.

     

The effects of mullein plants (Verbascum thapsus) on the population dynamics of Dicyphus hesperus (Heteroptera: Miridae) in tomato greenhouses

The response of Dicyphus hesperus Knight (Heteroptera: Miridae) to whitefly populations in tomato greenhouses was measured in the presence and absence of mullein (Verbascum thapsus L.) as an alternative host plant. The dynamics of the D. hesperus population on tomato (Lycopersicon esculentum Mill.) and on mullein plants were followed through an entire growing season. In houses with mullein plants, more predators occurred on mullein when whitefly density was low on tomato. A mark-release-recapture experiment where rabbit IgG was used as an external marker showed that D. hesperus adults moved from mullein plants to tomato plants. D. hesperus was always more abundant in houses with mullein than in the houses with tomato plants alone. Movements between tomato and mullein plants are discussed as a strategy to optimize predator foraging. The use of mullein as an alternative host plant may contribute to the establishment of D. hesperus and help to preserve the predator population when prey on tomato crops is scarce.     

Escape of Lygus hesperus (Heteroptera: Miridae) Eggs from Parasitism by Anaphes iole (Hymenoptera: Mymaridae) in Strawberries: Plant Structure Effects

Herbivorous insects in natural and agricultural systems experience variation in parasitoid attack on different plant species due to direct and indirect plant influences on parasitoids. Lygus hesperus is a native polyphagous mirid that suffers up to 100% parasitism by the native egg parasitoid Anaphes iole in certain weed hosts, but with inundative releases in commercial strawberries, we achieve <65% L. hesperus suppression. We examined L. hesperus egg distribution in individual strawberry plants and parasitism by A. iole of eggs in different strawberry plant structures to determine whether plant-related factors affected parasitoid performance in strawberries. L. hesperus laid more eggs (46.5% of all eggs laid) in the fruit (between the achenes [seeds] in the fleshy receptacle) than in the petiole (23.3%), leaflet (20.3%), peduncle (6.2%), or calyx (3.7%). In a no-choice test, parasitism by A. iole was higher in the petiole (96.7%), calyx (91.9%), and leaflet (85.2%) than in the fruit (51.8%), in which the achenes appeared to hinder parasitoid access to host eggs. In addition, in young fruits in which the interachene distance was minimum, parasitism was considerably lower (25.4%) than in fruits in which receptacle swelling had resulted in interachene distances that were medium (65.7% parasitism) or large (77.1% parasitism). Our results suggest that strawberry fruits can provide refugia from parasitism by A. iole and that maximum protection occurs when the achenes are contiguous. The presence of refugia in strawberries limits the impact of augmentative biological control with A. iole, highlighting the need for its integration with other strategies to effectively suppress L. hesperus in strawberries.     

Salivary amino acids in Lygus species (Heteroptera:Miridae)

Free and protein-bound amino acids were investigated in the phytophagous bug Lygus rugulipennis and its salivary gland. Over 38 substances were separated. The total content of amino compounds in the insects was about 1400 μmol/g fr. wt (16% by weight), of which 97% was amino acid residues in proteins.The salivary glands, which comprise about 1.5% of the live weight of the insects, contain 3.5% of the total free amino acids and 1% of the whote insect. Free and protein-bound amino acids comprise, respectively, about 1.4 and 11.6% of the fresh weight of the gland. The total concentration of free amino acids in the saliva was estimated to range from 0.5 to 2.2% by weight (ca. 0.1 M).The composition of free amino acids in the salivary gland of Lugus varies markedly. In four studied species (L. rugulipennis, L. gemellatus, L. pratensis, L. punctatus), the most abundant compounds were proline, arginine, lysine, leucine, glutamic acid, methionine sulphoxide and glycerophosphoethanolamine. In whole specimens of L. rugulipennis the predominant free amino acids were proline, alanine, taurine, glutamic acid, glutamine and methionine sulphoxide. The most abundant amino acids in proteins were glutamic and aspartic acid, glycine, alanine and leucine. The results indicate that the amino acid composition in the salivary glands of Lygus species does not differ markedly from that of the whole insect. The functions of salivary amino acids are discussed.     

Biology, immature stages and rearing of cocoa-capsids (Miridae: Heteroptera)

Some aspects of the biology of four West African capsid pests of Cocoa, Distantiella theobroma (Distant), Sahlbergella singularis Haglund, Bryocoropsis laticollis Schumacher and Helopeltis corbisieri Schmitz (Miridae: Heteroptera) are briefly summarized. Their immature stages are described and sketched in detail. Keys to distinguish all the larval stages are given and the techniques for rearing them reviewed. The systematics of Bryocorinae is discussed.     

Sampling of Nesidiocoris tenuis (Heteroptera: Miridae) in tomato crops

The number of N. tenuis on the upper, middle, and bottom leaves of tomato plants was correlated; nymphs were most abundant on middle and adults on upper leaves. The dispersion pattern of N. tenuis is aggregated and can be described using a negative binomial distribution. A binomial sampling method is proposed.     

The Host Range ofEccritotarsus catarinensis(Heteroptera: Miridae), a Potential Agent for the Biological Control of Waterhyacinth (Eichhornia crassipes)

The host range ofEccritotarsus catarinensiswas determined using 33 plant species to assess the risk of using this insect, a native of South America, for the classical biological control of waterhyacinth (Eichhornia crassipes) in Australia and Papua New Guinea. The results, in conjunction with the results of Hillet al.(1999) who tested 67 species (mostly South African), strongly suggest thatE. catarinensisis restricted to the Pontederiaceae, a family of aquatic plants. All five species of Pontederiaceae in the Australian testing,E. crassipes, Pontederia cordata, Monochoria vaginalis, M. cyanea,andM. australasica,were suitable for insect development. Colonies persisted for at least four generations onE. crassipes, P. cordata,andM. vaginalis.Two-way choice and multiple-choice preference trials were conducted and discussed.E. catarinensisdid not exhibit a clear preference for waterhyacinth over other Pontederiaceae in these trials. Most oviposition occurred into the upper surface of the lamina during laboratory testing despite observations that the underside was preferred in the field. Although not considered suitable for release in Australia, this insect may be useful in other countries where more serious waterhyacinth problems occur and whereM. vaginalisis a serious weed, such as in Southeast Asia.     

Patterns of speciation in the genus Lopidea (Heteroptera: Miridae: Orthotylinae)

Abstract. Speciation in four monophyletic species groups of the mirid genus Lopidea is examined. An analysis of twelve speciation events suggests that vicariance can account for at least 50% of speciation in Lopidea , and the frequency of sympatric host plant speciation may be as high as 25%.
In examples attributable to peripheral isolate speciation, the daughter taxa typically occur in recognized areas of endemism, suggesting a common cause (vicariance) for their origins. In addition, seven zones of disjunction between subspecies and allopatric sister species were identified for Lopidea , which correspond with similar disjunctions between sister taxa in other groups of organisms.     

Percussion signals of Lygus rugulipennis Poppius (Heteroptera: Miridae)

The European tarnished plant bug (Lygus rugulipennis Poppius) is among the most serious pests in the family Miridae, and therefore there is increasing interest in understanding the behaviour of this species. In the present study, laboratory recordings were taken using a laser vibrometer on adult males and females to ascertain whether acoustic signals are involved in intraspecific communication. Recordings were both carried out on plant and loudspeaker membrane substrates. Males and females emitted vibratory signals and the present results indicate that these signals are important during courtship. The basic signal characteristics measured were the dominant frequency, pulse duration, repetition time and number of pulses per group within the signal. Male and female signals did not differ in respect to any of these characteristics. Plant recorded signals were longer because of different mechanical properties of substrates. Additionally, the high frequency components were attenuated due to the low-pass filtering properties of plants. As this is the first study on vibratory communication of the European tarnished plant bug, we believe these findings may contribute considerably to the better understanding of the mating behavior of this important pest species.     

Morphology of the Phytophagous bug Platyscytus decempunctatus (Carvalho) (Heteroptera: Miridae)

Platyscytus decempunctatus Carvalho is a small mirid living throughout its life cicle plant Solanum cernuum Vell. (Solanaceae). The internal morphology of P. decempunctatus was studied and found that the female has a telotrophic ovary with three ovarioles in the right ovary and five in the left one. In the male reproductive trait there is a well developed tubular accessory gland. The phytophagous feeding habitat of P. decempunctatus was confirmed by the observations of chlorophyll pigments in the gut of all dissected specimens. The tubular salivary glands and the Malpighian tubules were also discussed.     

盲蝽科一中国新记录属及新记录种

记述盲蝽科Miridae1中国新记录属：薇盲蝽属Monalocoris Dahlbohm,1851及1新记录种,薇盲蝽Monalocoris filicis (Linneaus,1758)。     

The feeding habits of the Miridae (Heteroptera) living on broom (Sarothamnus scoparius (L.) Wimm.)

The natural food of five species of Miridae was studied by means of the precipitin test. Besides feeding on broom, all feed to some extent on other small arthropods. None showed any specificity in their attack and the species of prey taken depends on size and availability.

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Zusammenfassung Die natürliche Nahrung von 5 Arten der Miriden (Heterocordylus tibialis, Asciodema obsoletum, Orthotylus adenocarpi, O. virescens, and O. concolor) wurde mit Hilfe des Präzipitintests untersucht. Alle diese Arten fressen an ihrer Wirtspflanze und treten ausserdem auch als Räuber an der auf diesen Pflanzen lebenden Fauna auf. Die Angriffstechnik dieser Arten gab keinerlei Anhaltspunkte für eine Spezialisierung, und es ist wahrscheinlich, dass ihre Beute aus beliebigen kleinen, verhältnismässig trägen Arthropoden besteht. Die älteren Stadien sind besser als die jüngeren befähigt, grössere und lebhaftere Tiere zu erbeuten. O. virescens scheint weniger räuberisch zu sein als die anderen Arten. Auch ist ihre Art und Weise an der Wirtspflanze zu fressen mehr spezialisiert; denn sie ernährt sich hauptsächlich von dem Inhalt der Palisadenzellen und des Schwammparenchyms der Blätter. Die anderen Arten saugen an den jungen Stengeln, indem sie ihre Stechborsten in das Phloëm der Gefässbündel versenken.

     

Phenology of the Predatory Bugs Orius vicinus (Heteroptera: Anthocoridae) and Sejanus albisignata (Heteroptera: Miridae) in Otago, New Zealand, Apple Orchards

The phenology of the anthocorid, Orius vicinus and the mirid, Sejanus albisignata , was studied in apple orchards in Otago, New Zealand, from 1995 to 1998. The bugs were sampled on shoot and fruit clusters, and with beating trays and passive sticky traps. Three age classes of each bug were identified in the cluster and tray sampling, while the traps caught only adults. Both cluster and beating tray sampling successfully identified the generations. O. vicinus completed two generations per year with peak numbers of adults of each generation occurring in January and February/March, respectively. A very small partial third generation occurred in the warmest season. Adult females from the second generation overwintered. S. albisignata completed two full generations and a partial third generation each season. Peak adult numbers of each generation occurred, respectively, in December/January, February/March and April/May. S. albisignata overwinters in the egg stage but the proportions of these eggs from the three generations are not known. Both O. vicinus and S. albsignata are polyphagous and a range of their known prey species coexist with them on the apple trees in spring and summer.