Host plant use for oviposition by Trigonotylus caelestialium (Hemiptera: Miridae) and Stenotus rubrovittatus (Hemiptera: Miridae)

The main hosts and sites of oviposition for the two bugs, Trigonotylus caelestialium (Kirkaldy) (Hemiptera: Miridae) and Stenotus rubrovittatus (Matsumura) (Hemiptera: Miridae), that cause pecky rice were investigated in 24 poaceous plants. Nymphs of T. caelestialium emerged from both spikelets and leaf sheaths, while nymphs of S. rubrovittatus emerged almost exclusively from spikelets. Suitable plants for oviposition by T. caelestialium are Lolium multiflorum, Digitaria violascens and Hordeum murinum, while Poa annua, Anthoxanthum odoratum, Alopecurus aequalis and D. violascens were preferentially used by S. rubrovittatus. There was a greater difference in the number of nymphs emerging from different plants for S. rubrovittatus than for T. caelestialium. This difference may be because T. caelestialium can oviposit on leaf sheaths if the spikelets are not suitable for oviposition, whereas S. rubrovittatus only oviposits on spikelets. Although both bugs oviposited on spikelets, the internal oviposition sites were different. In D. ciliaris, T. caelestialium laid all eggs between the lemma of the first floret and the second floret, whereas S. rubrovittatus laid eggs almost exclusively inside the second floret. In contrast, in P. annua, T. caelestialium laid all eggs inside the florets, whereas S. rubrovittatus laid eggs both between and inside the florets.     

Seasonal Development of Plant Bugs (Heteroptera,Miridae): Subfamily Mirinae,Tribe Stenodemini

Entomological Review - The seasonal adaptations of 8 better studied species belonging to 4 genera of the tribe Stenodemini are analyzed. A univoltine seasonal cycle with obligate diapause is...     

Seasonal Migration of Apolygus spinolae (Hemiptera: Miridae) between Grapevines and Herbaceous Plants

This study was conducted to verify the seasonal migration of Apolygus spinolae (Meyer-Dür) between grapevines and herbaceous plants. Overwintering eggs were hidden in the hair layer under grapevine bud scales. A. spinolae adults were captured on sticky traps in the grapevine yard from late spring to early summer, dwindled through the summer, and captured again in late fall. However, adults were observed from early summer in herbaceous plant fields. A. spinolae adults were abundant during the summer of July and August in the herbaceous field, and thereafter its density decreased through fall. A few or no A. spinolae was found on mesh-netted grapevines after the installation year of the mesh-net, which indicated that A. spinolae adults migrating to lay overwintering eggs during the autumn could not land at the grapevines because of the mesh-net. Damaged shoots by A. spinolae were concentrated near the edge of grapevine yards bordering the herbaceous plants. This distribution pattern of shoot damage was believed to be related to an oviposition behavior of A spinolae, reflecting that adults migrating from herbaceous plants lay eggs more frequently in grapevines adjacent to the summer host plants. Seasonal occurrence of A. spinolae in grapevine yards was suggested as follows: A. spinolae overwinter as eggs in dormant buds on grapevines and hatch in the spring. Nymphs feed on grapevines then develop to adults (spring population), and migrate to herbaceous plants. A. spimolae spends the summer on the herbaceous hosts (summer population). Then, adults migrate back to grapevines in late autumn and lay overwintering eggs.     

The flight behaviour of cocoa-capsids (Hemiptera: Miridae)

The cocoa-capsid Distantiella theobroma flies from its canopy substrate spontaneously but when disturbed first falls 1.2 to 1.9 m before flying. Adults are capable of flight 18 to 20 hr after the final moult. Flight is directly sunwards when the sun is low, but when it is high the bugs fly upwards in spirals and zigzags. Flight is terminated by the sight of vertical objects. Mean flight speed is 3.1±0.5 m/sec at 23°. Potential range is at least 1.1 km in females, 2.3 km in males. The other cocoa-capsid, Sahlbergella singularis, differs in being markedly nocturnal in its dispersal flights. Males fly far more often than females.Other factors affecting flight are discussed and the implications of the flight potential for control methods are mentioned. No part of Ghana's cocoa is out of range of colonisation by either species.

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Résumé Le Capside du Cacao Distantiella theobroma s'envole spontanément et directement de son support, mais quand l'insecte est dérangé, il se laisse d'abord tomber et ne prend son vol qu'après une chute de 1,2 à 1,9 m. Les adultes sont capables de voler dans un délai de 18 à 20 h. après la dernière mue. Leur vol est orienté en direction du soleil quand celui-ci est bas sur l'horizon, mais s'il est haut l'insecte s'élève vers le ciel en effectuant des spirales et zig-zags. La vue de tout objet vertical provoque l'arrêt du vol et la pose sur ce support. La vitesse moyenne du vol est de 3,1±0,5 m/sec. à une température de 23°. Le rayon de vol est au moins de 1,1 km pour les femelles et de 2,3 km pour les mâles. L'autre punaise du cacao Sahlbergella singularis diffère de la précédente, ses vols de dispersion étant nettement nocturnes. Les mâles volent beaucoup plus souvent que les femelles.D'autres facteurs affectant le vol sont également discutés ainsi que les conséquences des potentialités de vol pour la mise au point de méthode de lutte. Toutes les zones du Ghana où se trouvent des plantations de cacao sont dans le périmètre de dispersion de chacune des deux espèces.

     

Comparative Mitogenomic Analysis of Damsel Bugs Representing Three Tribes in the Family Nabidae (Insecta: Hemiptera)

Background

Nabidae, a family of predatory heteropterans, includes two subfamilies and five tribes. We previously reported the complete mitogenome of Alloeorhynchus bakeri, a representative of the tribe Prostemmatini in the subfamily Prostemmatinae. To gain a better understanding of architecture and evolution of mitogenome in Nabidae, mitogenomes of five species representing two tribes (Gorpini and Nabini) in the subfamily Nabinae were sequenced, and a comparative mitogenomic analysis of three nabid tribes in two subfamilies was carried out.

Methodology/Principal Findings

Nabid mitogenomes share a similar nucleotide composition and base bias, except for the control region, where differences are observed at the subfamily level. In addition, the pattern of codon usage is influenced by the GC content and consistent with the standard invertebrate mitochondrial genetic code and the preference for A+T-rich codons. The comparison among orthologous protein-coding genes shows that different genes have been subject to different rates of molecular evolution correlated with the GC content. The stems and anticodon loops of tRNAs are extremely conserved, and the nucleotide substitutions are largely restricted to TψC and DHU loops and extra arms, with insertion-deletion polymorphisms. Comparative analysis shows similar rates of substitution between the two rRNAs. Long non-coding regions are observed in most Gorpini and Nabini mtDNAs in-between trnI-trnQ and/or trnS2-nad1. The lone exception, Nabis apicalis, however, has lost three tRNAs. Overall, phylogenetic analysis using mitogenomic data is consistent with phylogenies constructed mainly form morphological traits.

Conclusions/Significance

This comparative mitogenomic analysis sheds light on the architecture and evolution of mitogenomes in the family Nabidae. Nucleotide diversity and mitogenomic traits are phylogenetically informative at subfamily level. Furthermore, inclusion of a broader range of samples representing various taxonomic levels is critical for the understanding of mitogenomic evolution in damsel bugs.     

条赤须盲蝽形态特征与生物学特性

【目的】明确条赤须盲蝽Trigonotylus coelestialium各虫态的形态特征及其发育历期和成虫繁殖力等生物学特性,为条赤须盲蝽的预测预报及科学防治提供理论依据。【方法】在2021年9-10月郑州室内自然变温(22.0~28.1℃)和25℃恒温条件下,以玉米灌浆期籽粒为食料进行饲养,并观察、记录条赤须盲蝽个体各发育阶段的形态特征,测定其各虫态的发育历期、存活率、成虫寿命及雌成虫产卵量。【结果】条赤须盲蝽卵块产于玉米籽粒基部内颖内侧,卵粒长圆筒形,向一侧略弯。从1龄若虫开始触角呈现红色,随龄期增加红色逐渐明显,至5龄若虫时触角第1节出现3条清晰可见的红色纵纹。翅芽从3龄若虫开始明显可见。雌成虫产卵器长瓣状,平放于生殖节中部的沟槽内。室内自然变温下,条赤须盲蝽卵历期为6.27 d,卵孵化率为89.90%;1-5龄若虫历期分别为2.80, 2.33, 2.70, 2.77和3.90 d,若虫总历期为14.50 d,若虫总存活率为85.97%;雌成虫产卵前期为4.43 d,产卵持续期为13.93 d,单雌产卵19.47块,产卵量为82.55粒。25℃恒温下,条赤须盲蝽卵历期为7.73 d,卵孵化率为81.13%;1-5龄若虫历期分别为2.17, 1.90, 1.77, 1.90和2.93 d;若虫总历期为10.67 d,若虫总存活率为7184%;雌成虫产卵前期为4.17 d,产卵持续期为11.27 d,单雌产卵21.17块,产卵量为72.22粒。【结论】条赤须盲蝽的5龄若虫和成虫的触角第1节的形态特征可用于区分其与该属其他昆虫;其翅芽的发育特征可判别若虫龄期;变温能延长其若虫历期和成虫寿命,同时有利于提高雌成虫产卵量和卵孵化率。     

Sampling of Cacopsylla pyri (Hemiptera: Psyllidae) and Pilophorus gallicus (Hemiptera: Miridae) in pear orchards

The psyllid Cacopsylla pyri L. (Hemiptera: Psyllidae), is one of the principal pests of pear (Pyrus spp.) orchards and, along with its natural enemies, needs to be carefully monitored for correct integrate pest management and biological pest control decision making. We compare sampling techniques and develop sampling methods for C. pyri and Pilophorus gallicus Remane (Heteroptera: Miridae). Four pear orchards were sampled periodically from 2007 to 2010 in southern Spain by beating branches into funnels or 45-cm-diameter nets and taking shoot samples. Different sampling techniques were compared, and several sampling methods were assayed for adults and nymphs of C. pyri and P. gallicus. Psylla adult and P. gallicus counts in the nets and funnels were similar and closely correlated. Counts of C. pyri adults in the funnels and nets were higher than on shoots, but all measures were closely correlated. The number of nymphs on shoots and leaves was correlated, as were the counts on leaves within shoots. A guide for choosing the sampling unit in cost/precision terms is given. C. pyri nymphs and adults showed an aggregated distribution, whereas P. gallicus had a less-crowded spatial distribution. Enumerative sequential sampling was evaluated for both insects by using the different sampling techniques by resampling experimental data. The negative binomial distribution fitted the experimental data gathered using the different sampling techniques for C. pyri adults and P. gallicus. The use of binomial sampling is discussed for the two insects and the costs involved are compared with those implied in the sequential enumerative method.     

Revision of New Zealand Orthotylinae (Insecta: Hemiptera: Miridae)

Abstract

Six genera and 11 species of Orthotylinae are now known from New Zealand. Zanchius Distant is newly recorded. One new genus, Tridiplous, and seven new species of endemic New Zealand Orthotylini are described and illustrated. Four new species are described in Tridiplous: T. burrus, T. parvapiatus, T. penmani, and T. virens, and three new species are described in Zanchius: Z. ater, Z. rubicrux, and Z. totus. Keys are provided to identify New Zealand taxa of the tribes of Orthotylinae, genera and species of Halticini, genera of Orthotylini, and species of Tridiplous and Zanchius. The bugs are illustrated with colour habitus photos, and drawings including male and female genitalia. Economic importance is discussed.     

Mating preferences of two species of Eccritotarsus (Hemiptera: Miridae)

ABSTRACT

Eccritotarsus spp. are biological control agents that have been sourced from Brazil and Peru to control water hyacinth in South Africa. These agents have been released in over 30 sites and were thought to be the same species. The sequencing of mitochondrial DNA and interbreeding experiments have since confirmed the cryptic species to be separate species. The Brazilian population remains E. catarinensis while the Peruvian population is now E. eichhorniae. This paper assessed the mating behaviour of both species, to investigate behavioural traits that have resulted in reproductive isolation, which could have led to speciation. Mating choices in a form of no-choice, bi-choice and multi-choice tests were conducted within and between species in a 3:1, 2:1 and 1:1 sex ratio. The E. eichhorniae pair had more single and multiple copula incidences, higher average total copula duration and higher copula latency while the E.catarinensis♀×E.eichhorniae♂ pair had less single and multiple copula incidences, lower average total copula duration and lower copula latency. When the E.eichhorniae♀ and E.catarinensis♂ were given their respective choices, they only mated with conspecifics. However, when E.eichhorniae♀ are crossed with E.catarinensis♂ they do not produce offspring. These results suggest that interbreeding will be limited in South Africa.     

Temperature dependent development of Lygus hesperus (Hemiptera: Miridae) nymphs

Lygus hesperus Knight (Hemiptera: Miridae) is a key pest of fruit and vegetable crops, forages, and cotton (Gossypium spp.) in the western United States. Accurate models describing relationships between temperature and L. hesperus development are critical to the study of seasonal L. hesperus population dynamics. Development of L. hesperus nymphs was assessed at nine constant temperatures from 10 to 37.8 degrees C. The relationships between temperature and development for each L. hesperus instar, and for the entire nymphal stage, were best described by six-parameter biophysical models indicating both low- and high-temperature inhibition of development. Development rates asymptotically approached zero with decreasing temperature in the lower thermal range, and decreased with increasing temperatures above 32.2 degrees C. Nymphs did not survive from egg hatch to adulthood at either 10 or 37.8 degrees C, and nymph mortality was > 90% at both 12.8 and 35.0 degrees C. The fifth instar exhibited the longest stadium, whereas the shortest stadia were associated with the second and third instars. Development rates of males and females did not differ, and the ratio of males to females was not different from 1:1 at any temperature. Our temperature-dependent development rate models for L. hesperus nymphs will facilitate control of insect physiological age in controlled laboratory experiments, and should be useful in planning and interpreting field studies on L. hesperus population dynamics.     

黑肩绿盲蝽口器的结构和感器

黑肩绿盲蝽Cyrtorhinus lividipennis Reute是水稻飞虱和叶蝉的重要天敌。为了更好的探讨这种盲蝽的取食行为,本研究在扫描电镜下观察了黑肩绿盲蝽口器及其感器的超微结构。结果表明黑肩绿盲蝽口针束由1对上颚针和1对相互连锁的下颚针构成。上颚口针具两排脊状突起,并通过连锁机制紧密的嵌合在一起,形成了中空的食物道和唾液道。下颚口针内侧边缘具两排与口针末端方向一致的锐利齿状结构。黑肩绿盲蝽口器上可观察到毛形感器Ⅰ(TSⅠ)、毛形感器Ⅱ(TSⅡ)、锥形感器(BS)和多孔钉形感器(MPGS),大都分布于口器下唇,尤其在下唇端部可见锥形感器密集分布。研究结果对今后进一步探讨这种天敌的食性和取食行为有重要意义。     

绿盲蝽腹神经节的解剖结构

【目的】揭示绿盲蝽Apolygus lucorum腹神经节的组成结构。【方法】采用免疫组织化学染色方法,利用突触蛋白抗体对绿盲蝽成虫的腹神经节进行免疫标记,激光共聚焦扫描显微镜扫描照相获得原始数据,用图像分析软件进行标记,构建三维结构模型。【结果】绿盲蝽成虫腹神经节位于腹神经索的末端,与其前方的后胸神经节和中胸神经节紧密融合,形成后部神经节。与脑和胸神经节类似,腹神经节由周围的细胞体和内部的神经髓构成。腹神经节的神经纤维束主要包括位于腹侧的两条纵向神经连索和向两侧发出的9束神经纤维。9束神经纤维连接着9个神经原节,即富含突触联系的神经髓。这些神经原节紧密融合,无明显的边界,最后两节形成膨大的末端腹神经节。两侧的神经原节由横向的神经连锁连接起来。腹神经节外周的细胞体数量较多,排列紧密,大小一致,仅在前端背侧中间和后端腹侧中间位置分别有2个和5个体积较大的细胞体。【结论】本研究结果明确了绿盲蝽腹神经节的结构,为进一步研究昆虫的行为调控及神经系统发育和演化奠定一定的形态学基础。     

Microbial community of predatory bugs of the genus Macrolophus(Hemiptera: Miridae)

Background

The predatory mirids of the genus Macrolophus are key natural enemies of various economically important agricultural pests. Both M. caliginosus and M. pygmaeus are commercially available for the augmentative biological control of arthropod pests in European greenhouses. The latter species is known to be infected with Wolbachia -inducing cytoplasmic incompatibility in its host- but the presence of other endosymbionts has not been demonstrated. In the present study, the microbial diversity was examined in various populations of M. caliginosus and M. pygmaeus by 16S rRNA sequencing and denaturing gradient gel electrophoresis.

Results

Besides Wolbachia, a co-infection of 2 Rickettsia species was detected in all M. pygmaeus populations. Based on a concatenated alignment of the 16S rRNA gene, the gltA gene and the coxA gene, the first is phylogenetically related to Rickettsia bellii, whereas the other is closely related to Rickettsia limoniae. All M. caliginosus populations were infected with the same Wolbachia and limoniae-like Rickettsia strain as M. pygmaeus, but did not harbour the bellii-like Rickettsia strain. Interestingly, individuals with a single infection were not found. A PCR assay on the ovaries of M. pygmaeus and M. caliginosus indicated that all endosymbionts are vertically transmitted. The presence of Wolbachia and Rickettsia in oocytes was confirmed by a fluorescence in situ hybridisation. A bio-assay comparing an infected and an uninfected M. pygmaeus population suggested that the endosymbionts had minor effects on nymphal development of their insect host and did not influence its fecundity.

Conclusion

Two species of the palaearctic mirid genus Macrolophus are infected with multiple endosymbionts, including Wolbachia and Rickettsia. Independent of the origin, all tested populations of both M. pygmaeus and M. caliginosus were infected with three and two endosymbionts, respectively. There was no indication that infection with endosymbiotic bacteria had a fitness cost in terms of development and fecundity of the predators.

     

Physiological consequences of laboratory rearing of Lygus hesperus (Hemiptera: Miridae)

Several aspects of the basic biology of the western tarnished plant bug, Lygus hesperus Knight, are poorly known despite the economic importance of this species. Among these are the factors regulating the adult diapause. Reports of recent studies questioned the validity of earlier reports of diapause in L. hesperus, in part because of the demonstrated loss of diapause response in insects obtained from long-standing laboratory colonies. However, use of laboratory reared insects would facilitate additional diapause research, so long as those insects exhibit a diapause response similar to that of the field population. L. hesperus, originating as eggs from field-collected insects, were reared in the laboratory for four generations to examine corresponding changes in selected biological characteristics. Over the course of the four generations, incidence of diapause in both L. hesperus genders decreased whereas the frequency of oviposition by virgin females increased. Measurable changes were not observed in frequency of occurrence of a specific fat body type (glass bead fat) or nymphal development time. These results suggest L. hesperus used in diapause research should be as close to the field population as possible, but no further removed than three generations. Results further demonstrate variability among different biological characteristics in their responses to selection from laboratory rearing. Collectively, these findings demonstrate the importance of understanding the influences of rearing on specific biological characteristics under study, and the need to verify the similarity of laboratory-reared insects to their native counterparts in studies used to draw inferences regarding the field population.     

Reciprocal intraguild predation between two mirid predators,Cyrtorhinus lividipennis and Tytthus chinensis (Hemiptera: Miridae)

Interactions between predator species shape ecological communities and are crucial in the relationship between biodiversity and ecosystem functioning. They contribute to improving the natural biological control. Cyrtorhinus lividipennis Reuter and Tytthus chinensis Stål (Hemiptera: Miridae) are important natural enemies of brown planthopper, Nilaparvata lugens Stål (Hemiptera: Delphacidae), the most destructive rice pest in Asia. Comparative functional responses of both sexes of the two mirids at different development stages were estimated and the direction, symmetry, as well as intensity of intraguild predation (IGP) were studied in the laboratory. Prey preferences of the two mirid species and the influence of alternative prey on functional responses were also evaluated. The mirids exhibited reciprocal IGP in addition to consuming eggs of BPH. All predator–prey combinations exhibited a type II functional response. Females and fourth instar nymphs of C. lividipennis showed greater voracity for eggs of BPH than of T. chinensis. The two mirids were more voracious to intraguild prey than to extraguild prey. Alternative prey released the functional responses of C. lividipennis to both intra- and extraguild prey. In contrast, alternative prey had no effect on the functional response of T. chinensis. RIGP was symmetrical in the absence of extraguild prey. And in the presence of extraguild prey that was common in the field, resulted in different responses by the mirids.     

Taxonomic Review of Creontiades Distant in Australia (Hemiptera: Miridae: Mirinae)

The two species of Creontiades Distant occurring in Australia, C. dilutus (Stål) (Australian endemic) and C. pacificus (Stål) (China, several countries in the Oriental and Australian regions including Tahiti and Micronesian islands) are redescribed, illustrated and their distributions are mapped. Megacoelum modestum (Distant) and C. virescens Reuter are synonymised with C. dilutus , and C. pallidifer (Walker) with C. pacificus. Available host plant information is provided for both species. C. dilutus , commonly known as green mirid, is a pest of cotton, potato, stone fruit, lucerne and other crops in certain parts of Australia. the generic limits of Creontiades and the closely related, world-wide distributed Megaceolum Fieber are reviewed based on examination of Australian species and the type species.