Systematics and biogeography of Australian rhopalosomatid wasps (Hymenoptera: Rhopalosomatidae) with a global synopsis of the enigmatic genus Olixon Cameron

Abstract The wasp family Rhopalosomatidae is represented in Australia only by the genus Olixon Cameron. Species of this genus have previously been considered rare based on material in collections and have rarely been observed in the field. All known species of Olixon are brachypterous, solitary ectoparasitoids of crickets (Orthoptera: Gryllidae). Prior to our study the world fauna comprised 11 species of which two were endemic to north‐eastern Australia. Based on specimens collected during recent intensive surveys in Australia we record 17 species for the continent. Fifteen of these species are described as new, which more than doubles the world fauna of Olixon: Olixon abrahami, O. danggari, O. ferrugineum, O. guyim, O. harveyi, O. helgae, O. jandakotae, O. jawoyn, O. jenningsi, O. kakadui, O. pilbara, O. wajuk, O. waldockae, O. wuthathi and O. zonale spp.n . Females of Olixon australiae Perkins and Olixon flavibase Townes are redescribed, and the male of O. flavibase is described for the first time. A key is provided for all 17 Australian species and their distribution is discussed. Results of a cladistic analysis of the world species of Olixon based on 41 morphological characters for 24 ingroup species are presented. The results obtained from equal and implied weighting parsimony analyses indicate that: (i) the Australian species of Olixon are not monophyletic, (ii) about three‐quarters of the Australian species form a monophyletic group, and (iii) a Central/South American Olixon is sister to all other species. The implications of these results for the biogeography of world Olixon species are briefly discussed.     

Spring phenology in boreal Eurasia over a nearly century time scale

It has been widely reported that tree leaves have tended to appear earlier in many regions of the northern hemisphere in the last few decades, reflecting climate warming. Satellite observations revealed an 8-day advance in leaf appearance date between 1982 and 1991 in northern latitudes. In situ observations show that leaf appearance dates in Europe have advanced by an average of 6.3 days from 1959 to 1996. Modelling of leaf appearance on the basis of temperature also shows a marked advance in temperate and boreal regions from 1955 to 2002. However, before 1955, reported studies of phenological variations are restricted to local scale. Modelling, ground observations and satellite observations are here combined to analyse phenological variations in Eurasian taiga over nearly a century. The trend observed by remote sensing consists mainly in a shift at the end of the 1980s, reflecting a shift in winter and spring temperature. In western boreal Eurasia, a trend to earlier leaf appearance is evident since the mid-1930s, although it is discontinuous. In contrast, the strong advance in leaf appearance detected over Central Siberia using satellite data in 1982–1991 is strengthened by late springs in 1983–1984; moreover, in this region the green-up timing has displayed successive trends with opposite signs since 1920. Thus, such strong trend is not unusual if considered locally. However, the recent advance is unique in simultaneously affecting most of the Eurasian taiga, the leaf appearance dates after 1990 being the earliest in nearly a century in most of the area.     

Control of Trypanosoma brucei brucei infections in tsetse, Glossina morsitans

Abstract Numbers of immature Trypanosoma brucei brucei within a tsetse midgut remain remarkably constant after establishment throughout the course of an infection, irrespective of whether the infection eventually matures. These results suggest a system of self regulation of the parasite population in the insect gut based on a form of programmed cell death which would carry advantages for both the parasite and the vector.     

A NEW SIGNIFICANCE TEST FOR CONSENSUS IN GENERALIZED PROCRUSTES ANALYSIS

Generalized Procrustes Analysis is frequently used to find a consensus from sensory panel data. Recently King and Arents (1991) have proposed a goodness of fit of the consensus configuration based on Monte-Carlo simulations. A modified test is developed that retains the original assessor configurations by permutation of the data rows. This leads to a more powerful statistical test as is shown by application to data collected in the free-choice profiling of eight milk products.     

Use of space by the African Striped Ground Squirrel Xerus erythropus

Five Striped Ground Squirrels Xerus erythropus were radio-tracked at Katumani, Kenya, for periods of up to 10 days. The results were used to explore their short-term use of space. Definitions of the terms 'home range' and 'core', and some aspects of the methodology of home-range analysis are discussed. In an area of low-productivity bushland, subject to intermittent drought, where their food supply was patchy and unpredictable, the squirrels travelled about 1.5 km per day, and occupied rather large home ranges averaging 12.4 ha. Levels of aggression between conspecifics was low, home ranges were not defended, and there was considerable range overlap. Nights were spent in burrows which were commonly shared with conspecifics. On most days a single relatively long exploratory excursion was made outside the home range, extending the average area of the total range to some 40 ha. Despite the presence of major environmental features which might have been expected to affect the squirrels' foraging behaviour, such as cultivated fields, home range use was very symmetrical, suggesting that essential resources (food, shade, burrows) were widely dispersed throughout the range. Squirrels foraged alone, harvesting small, scattered, high-quality food items, mainly vegetable. Activity was interrupted from time to time to retire to the shade to lose heat, and a midday rest was taken. Only part of the home range was used each day. A variable degree of central concentration of activity could be observed. The squirrels' use of space enabled them to exploit available food resources opportunistically and efficiently, and made them difficult to control effectively.