Onset and spread of an African army worm upsurge

Abstract. 1. Onset and spread of the severe outbreaks of African armyworm, Spodoptera exempta (Walk.), over Ethiopa, Kenya, Tanzania and Burundi in late 1984 have been analysed in relation to trap and weather records.
2. Although first outbreaks in each country appeared progressively further south, winds on the best estimated dates of moth concentration and egg laying blew from directions precluding moth movements between them.
3. Such independently developing outbreaks are called 'primary' to distinguish them from any 'secondary' outbreaks that may develop from them.
4. Parent moths giving rise to all seven areas of primary outbreaks were derived from low-density populations that had persisted through the dry season, probably near the coast of East Africa.
5. Primary outbreaks developed on the south-eastern sides of individual rainstorms over the highlands, most likely because windborne moths were concentrated there by convergent winds.
6. Of the secondary outbreaks within Kenya, Tanzania and Burundi, most were derived from only one area of primary outbreaks in Kenya, which were therefore critical for effective control of spread; the paucity of other secondaries was presumably due to a lack of timely rainstorms or other concentrating mechanisms.     

Notes on the epidermal features of Degeneria vitiensis I. W. Bailey & A. G. Smith (Degeneriaceae)

The epidermis of leaves of Degeneria vitiensis is described by reference to cuticular morphologies. Paracytic stomata and enlarged stomata are recorded and the detailed structure of the former is described. A variety of other epidermal structures characterized by radially exerted influences upon the general epidermal pavement is also described. On the basis of comparisons with published accounts of the epidermis of other 'ranaleans' the original separation of Degeneria from the Magnoliaceae is supported. Degeneria is considered to have a closer epidermal affinity with some members of the Illiciales than with members of the Magnoliales to which the Degeneriaceae is currently assigned.     

A Survey of Argentine and Lebanese Bone for Salmonellas with Particular Reference to the Isolation of Salmonella typhimurium

The incidence of Salmonella typhimurium in imported bone meal may be underestimated by conventional isolation techniques because of the presence of other salmonella serotypes. A method was developed with a serological bias towards recovery of serotypes with 'i'as H phase 1 antigen. By this technique, 44 strains of S. typhimurium were isolated from Argentinian bone meal compared with nine strains cultured by the unbiased method. The technique was less successful with Lebanese bone. The serological technique was most effective when several salmonella serotypes not possessing the 'i'antigen were present in a sample. S. kentucky (8, 20:i:z₆), like S. typhimurium was also efficiently isolated by the serological method. In 12 specimens both S. typhimurium and S. kentucky were present. The two serotypes were easily separated by examining four 25 g sub-samples of the specimen.     

Insect diversity and trophic structure differ on native and non‐indigenous congeneric rushes in coastal salt marshes

Displacement of native plant species by non‐indigenous congeners may affect associated faunal assemblages. In endangered salt marshes of south‐east Australia, the non‐indigenous rush Juncus acutus is currently displacing the native rush Juncus kraussii, which is a dominant habitat‐forming species along the upper border of coastal salt marshes. We sampled insect assemblages on multiple plants of these congeneric rushes in coastal salt marshes in Sydney, New South Wales, Australia, and compared the abundance, richness, diversity, composition and trophic structure between: (i) J. acutus and J. kraussii at invaded locations; and (ii) J. kraussii at locations either invaded or not invaded by J. acutus. Although J. acutus supported a diverse suite of insects, species richness and diversity were significantly greater on the native J. kraussii. Moreover, insect assemblages associated with J. kraussii at sites invaded by J. acutus were significantly different from, and more variable than, those on J. kraussii at non‐invaded sites. The trophic structure of the insect assemblages was also different, including the abundance and richness of predators and herbivores, suggesting that J. acutus may be altering consumer interactions, and may be spreading in part because of a reduction in herbivory. This strongly suggests that J. acutus is not playing a functionally similar role to J. kraussii with respect to the plant‐associated insect species assemblages. Consequently, at sites where this non‐indigenous species successfully displaces the native congener, this may have important ecological consequences for community composition and functioning of these endangered coastal salt marshes.