The coconut pathosystem: weed hosts of nymphs of the American palm Cixiid Haplaxius crudus (Hemiptera: Fulgoroidea)

Lethal yellowing (LY) of coconut palm (Cocos nucifera L., Arecaceae) is a disease of economic importance that is caused by the phytoplasma ‘Candidatus Phytoplasma palmae’ and is transmitted by the planthopper Haplaxius crudus (Van Duzee) (Hemiptera: Cixiidae). This study explores the weeds used by H. crudus nymphs and other Cixiidae in a coconut pathosystem in southern Mexico. Nymphs were collected directly from the root system of each weed by hand or with the help of a vacuum after carefully opening the culm. This study included 11 species of weeds: nine Poaceae [Brachiaria decumbens Stapf, B. humidicola (Rendle) Schweick, B. mutica (Forssk.) Stapf, Digitaria abyssinica (Hochst. Ex A. Rich.) Stapf, Eustachys petraea (Sw.) Desv., Leersia hexandra Sw., Panicum laxum Sw., P. maximum Jacq., Paspalum notatum Flüggé]; one Cyperaceae [Cyperus ligularis L.], and one Portulacaceae: [Portulaca pilosa L.]. Brachiaria mutica, E. petraea, B. humidicola, P. maximum were identified as the principal host species for H. crudus nymphs. Brachiaria decumbens, D. abyssinica, and C. ligularis are new host records for the nymphs of H. crudus. Additionally, it was found that H. crudus may coexist with its cogeners H. skarphion Kramer (Cixiidae) and H. caldwelli Kramer (Cixiidae), on B. mutica. On C. ligularis, H. crudus may coexist with Oecleus snowi Ball (Cixiidae) nymphs. These results suggest that in the coconut pathosystem there is a complex of multitrophic interactions that should be considered in integrated management of LY.     

Polymorphism,taxonomy and host plant associations in Alebra leafhoppers (Homoptera: Cicadellidae: Typhlocybinae)

The taxonomy of a complex of morphologically similar Alebra species is clarified, and the number of adult colour pattern morphs of each in Britain, and their host plant associations, established. Morphological characters are figured for the identification of the four species now recognized, including two that are associated with different species of deciduous oaks and which were previously regarded as colour pattern morphs of A. albostriella. Three nymphal colour pattern morphs are described within the A. albostriella sibling species, two of which are shared, thus supplying further evidence for their close relationship. A key is given for the identification of the species and adult morphs of Alebra in Britain.     

蜉蝣稚虫蛋白质和酯酶同工酶的研究

本文报道了南京宽基蜉(Choroterpes nanjingensis You et al.)、扁蜉蝣(Heptaniasp.)和细蜉蝣(Caenis sp.)等三种不同科稚虫的全稚虫匀浆蛋白质等电点聚焦与酯酶同工酶的研究。结果表明:三种蜉蝣稚虫的蛋白质和酯酶同工酶的带型均有一定的差异.蛋白质和酯酶同工酶都以细蜉蝣的带数最多,扁蜉蝣次之,南京宽基蜉最少,而后两者带数较接近。     

Morphology of abdominal evaporatoria in larvae of some Lygaeoidea (Insecta: Hemiptera: Heteroptera): function and bearing on classification

The dorsal abdominal scent glands of nymphs in Lygaeoidea are diverse. Some related characters, such as number and distribution of dorsal abdominal scent gland openings (DSOs), and shapes of dark plates surrounding DSOs have been commonly used in taxonomic and/or phylogenetic studies of Lygaeoidea. However, comparative studies of the cuticular fine structures surrounding the DSOs in lygaeoid (and other Heteroptera) nymphs are few. We examined the cuticular fine structures surrounding DSOs of fifth‐instar nymphs of 25 species in seven families of Lygaeoidea with scanning electron microscopy. The results showed that the structures surrounding DSOs, such as distribution pattern of cell network, type of network, type of non‐latticed area, pattern of channels for glandular secretion, are complicated and diverse at the family level, indicating that they are valuable in taxonomic and phylogenetic analyses.     

The discovery of aeschnidiid nymphs (Aeschnidiidae, Odonata, Insecta)

Aeschnidiid nymphs are here first identified and described, and its phylogenetic relationship and bioecological characteristics are deduced. The nymphs known from China, Mongolia, Russia and Brazil and arranged in the family Aeschnidiidae are, in fact, unrelated to this group. All the known five Chinese species in four genera which were erected based on fossil nymphs and placed in the family Gomphidae may be transferred in Aeschnidiidae and merged into one alone, theSinaeschnidia cancellosa. It is a geographically widespread species from the “Jehol biota” of East Asia and appeared in the latest Late Jurassic age.