Fusca Group Research Articles

Hidden Potential of the Subdominant Ant Formica lemani Bondroit (Hymenoptera: Formicidae): The Formation of Large Nest Complexes and Restructuring Behavioural Stereotypes

The potential of subdominant ants of the Formica fusca group and their role in forests are still underestimated. Since ant behaviour is dependent on colony size, studying the functional organisation of nest complexes (NC) is most promising for a more accurate assessment of species capabilities. The study focused on the main ecological and ethological issues of the life activity of Formica lemani Bondroit within large NC (>150 nests) and beyond. After preliminary mapping of the F. lemani NC (main nests, trails, foraging trees), off-nest activity, aggressiveness, and trophobiotic relationships with aphids in and outside the NC territory were studied. Within the NC, the dynamic density, the intensity of movement on trails, and aggressiveness of F. lemani were significantly higher than beyond; the range of symbiont aphids was twice as small, with aphids on birches playing a key role in carbohydrate nutrition of F. lemani. The latter ensures accelerated restoration of trophobiotic interactions in spring and stability of the food supply until autumn. Combined with the lack of pressure from F. rufa group ants, this allowed F. lemani to maintain high population densities, and significantly increased its competitiveness, and role in plant protection against phytophages.

Viviparity and habitat restrictions may influence the evolution of male reproductive genes in tsetse fly (Glossina) species

BackgroundGlossina species (tsetse flies), the sole vectors of African trypanosomes, maintained along their long evolutionary history a unique reproductive strategy, adenotrophic viviparity. Viviparity reduces their reproductive rate and, as such, imposes strong selective pressures on males for reproductive success. These species live in sub-Saharan Africa, where the distributions of the main sub-genera Fusca, Morsitans, and Palpalis are restricted to forest, savannah, and riverine habitats, respectively. Here we aim at identifying the evolutionary patterns of the male reproductive genes of six species belonging to these three main sub-genera. We then interpreted the different patterns we found across the species in the light of viviparity and the specific habitat restrictions, which are known to shape reproductive behavior.ResultsWe used a comparative genomic approach to build consensus evolutionary trees that portray the selective pressure acting on the male reproductive genes in these lineages. Such trees reflect the long and divergent demographic history that led to an allopatric distribution of the Fusca, Morsitans, and Palpalis species groups. A dataset of over 1700 male reproductive genes remained conserved over the long evolutionary time scale (estimated at 26.7 million years) across the genomes of the six species. We suggest that this conservation may result from strong functional selective pressure on the male imposed by viviparity. It is noteworthy that more than half of these conserved genes are novel sequences that are unique to the Glossina genus and are candidates for selection in the different lineages.ConclusionsTsetse flies represent a model to interpret the evolution and differentiation of male reproductive biology under different, but complementary, perspectives. In the light of viviparity, we must take into account that these genes are constrained by a post-fertilization arena for genomic conflicts created by viviparity and absent in ovipositing species. This constraint implies a continuous antagonistic co-evolution between the parental genomes, thus accelerating inter-population post-zygotic isolation and, ultimately, favoring speciation. Ecological restrictions that affect reproductive behavior may further shape such antagonistic co-evolution.

A morphometric study on Ophrys sect. Pseudophrys in Apulia (Italy) and discovery of Ophrys japigiae sp. nov. (Orchidaceae)

In this study, morphometric analyses were conducted to explore and characterise the differences and analogies between almost all O. fusca s.l. taxa occurring in Apulia. Numerous morphological characters were considered, including 20 continuous variables, 5 ratios and one multistate condition. Our results constitute an exhaustive morphometrical analysis of taxa belonging to the O. fusca group found in Apulia, showing that most of the analysed species are morphologically well defined. Using morphological, phenological and chorological evidence, a new species from southern Italy, Ophrys japigiae sp. nov. is described and illustrated. Some conclusions are drawn with regard to species delimitation, comparing morphology, phenology, chorology and habitat markers.

Integrating restriction site-associated DNA sequencing (RAD-seq) with morphological cladistic analysis clarifies evolutionary relationships among major species groups of bee orchids.

Background and AimsBee orchids (Ophrys) have become the most popular model system for studying reproduction via insect-mediated pseudo-copulation and for exploring the consequent, putatively adaptive, evolutionary radiations. However, despite intensive past research, both the phylogenetic structure and species diversity within the genus remain highly contentious. Here, we integrate next-generation sequencing and morphological cladistic techniques to clarify the phylogeny of the genus.MethodsAt least two accessions of each of the ten species groups previously circumscribed from large-scale cloned nuclear ribosomal internal transcibed spacer (nrITS) sequencing were subjected to restriction site-associated sequencing (RAD-seq). The resulting matrix of 4159 single nucleotide polymorphisms (SNPs) for 34 accessions was used to construct an unrooted network and a rooted maximum likelihood phylogeny. A parallel morphological cladistic matrix of 43 characters generated both polymorphic and non-polymorphic sets of parsimony trees before being mapped across the RAD-seq topology.Key ResultsRAD-seq data strongly support the monophyly of nine out of ten groups previously circumscribed using nrITS and resolve three major clades; in contrast, supposed microspecies are barely distinguishable. Strong incongruence separated the RAD-seq trees from both the morphological trees and traditional classifications; mapping of the morphological characters across the RAD-seq topology rendered them far more homoplastic.ConclusionsThe comparatively high level of morphological homoplasy reflects extensive convergence, whereas the derived placement of the fusca group is attributed to paedomorphic simplification. The phenotype of the most recent common ancestor of the extant lineages is inferred, but it post-dates the majority of the character-state changes that typify the genus. RAD-seq may represent the high-water mark of the contribution of molecular phylogenetics to understanding evolution within Ophrys; further progress will require large-scale population-level studies that integrate phenotypic and genotypic data in a cogent conceptual framework.

A cytological study on Ophrys (Orchidaceae) in Italy: New evidence and the importance of polyploidy

This paper presents a cytological study of two recently described species of Ophrys from the Apulia region, which is one of the most important diversification centres of the genus. The basic chromosome number was x = 18 for the two species. Ophrys peucetiae Lozito, D'Emerico, Medagli & Turco has the karyotype 2n = 2x = 36: 24 m+12 sm, and O. pseudomelena Turco, Medagli & D'Emerico has 2n = 2x = 36: 30 m+6 sm. As observed in the O. fusca group, in O. pseudomelena, metacentric chromosomes predominate over submetacentric ones. In contrast, Ophrys peucetiae has a more evolved character, as seen in the standard karyotype of O. fuciflora s.l. On average, Ophrys peucetiae exhibited a more asymmetrical karyotype than O. pseudomelena. Variations in morphology and size in chromosome pair 1 were observed within both species. Studies on chromosome numbers in Ophrys taxa from Apulia and Sardinia revealed triploidy in Ophrys morisii (Martelli) Soò and tetraploidy in O. apulica (O. Danesch & E. Danesch) O. Danesch & E. Danesch and O. forestieri (Rchb. f.) Lojac. ( = O. lupercalis Devillers Tersch. & Devillers). The significance of the results is discussed in relation to previous information for this genus.

Comparative labellum micromorphology of the sexually deceptive temperate orchid genusOphrys: diverse epidermal cell types and multiple origins of structural colour

Labellum micromorphology was imaged via scanning electron and light microscopy in 32 microspecies and one artificial hybrid of the European terrestrial orchid genus Ophrys, together representing all ten macrospecies circumscribed in the genus via molecular phylogenetics. Imaging of homologous regions of the adaxial surface, paying particular attention to the diagnostic feature of the comparatively reflective speculum, revealed the presence of between three and seven epidermal cell types on each labellum, the less complex labella being plesiomorphic. Epidermal protuberances range from short, domed papillae to long, twisted unicellular filaments. Multiple origins are inferred for pale labellar margins, large yellow appendices (both putative osmophores exuding pseudopheromones), broad flat labella and long lateral horns. Homoplasy in the speculum is manifested in unusually complex or simple outlines and the presence or absence of a pale margin or iridescence. The reflectivity of the speculum is caused by a combination of chemical and physical colour, whereas iridescence can be caused only by physical properties. The specula of most microspecies studied bear striated trichomes, albeit maturing comparatively late in ontogeny and being sufficiently narrow to allow light to reach the flat polygonal trichome bases. Reflectivity appears to be negatively correlated with the convexity and degree of cuticular corrugation shown by these epidermal cells. Two clades (the Speculum + Tenthredinifera + Bombyliflora group and Bertolonii subgroup of the Sphegodes group) have lost specular trichomes and include the most iridescent species; their flat, polygonal, nonstriated cells resemble those observed on the paired pseudoeyes that bracket the stigmas of all Ophrys except the Fusca group. The smooth thick-layered cuticle and dense layers of organelles and starch bodies revealed by preliminary transmission electron microscopy study provide alternative candidates for the primary reflective surface of the speculum; in contrast, the trichomes and conical cells that dominate Ophrys labella, and occur on the specula of all but the most reflective species, absorb and/or diffuse light. Multiple MYB family genes are hypothesized to control epidermal micromorphology. The relative contributions of olfactory, visual and tactile cues to the sophisticated pseudocopulatory pollination mechanism that characterizes Ophrys remain unclear, but the degree of reproductive isolation achieved, and thus the speciation rate, have certainly been greatly exaggerated by most observers.

Olfactory and behavioural responses of tsetse flies, Glossina spp., to rumen metabolites

Herbivores provide tsetse flies with a blood meal, and both wild and domesticated ruminants dominate as hosts. As volatile metabolites from the rumen are regularly eructed with rumen gas, these products could serve tsetse flies during host searching. To test this, we first established that the odour of rumen fluid is attractive to hungry Glossina pallidipes in a wind tunnel. We then made antennogram recordings from three tsetse species (G. pallidipes morsitans group, G. fuscipes palpalis group and G. brevipalpis fusca group) coupled to gas chromatographic analysis of rumen fluid odour and of its acidic, mildly acidic and neutral fractions. This shows tsetse flies can detect terpenes, ketones, carboxylic acids, aliphatic aldehydes, sulphides, phenols and indoles from this biological substrate. A mixture of carboxylic acids at a ratio similar to that present in rumen fluid induced behavioural responses from G. pallidipes in the wind tunnel that were moderately better than the solvent control. The similarities in the sensory responses of the tsetse fly species to metabolites from ruminants demonstrated in this study testify to a contribution of habitat exploitation by these vertebrates in the Africa-wide distribution of tsetse.

Land cover and tsetse fly distributions in sub‐Saharan Africa

This study aims to provide trypanosomiasis-affected countries with standardized datasets and methodologies for mapping the habitat of the tsetse fly (Glossina spp., the disease vector) by customizing and integrating state-of-the-art land cover maps on different spatial scales. Using a combination of inductive and deductive approaches, land cover and fly distribution maps are analysed in a geographic information system (GIS) to estimate the suitability of different land cover units for the three groups (subgenera) of Glossina. All land cover datasets used for and produced by the study comply with the Land Cover Classification System (LCCS). At the continental scale, a strong correlation between land cover and tsetse habitat is found for both the fusca and palpalis groups, whereas a weaker correlation found for the morsitans group may be indicative of less restrictive ecological requirements. At the regional and national levels, thematic aggregation of the multi-purpose Africover datasets yielded high-resolution, standardized land cover maps tailored for tsetse habitat for eight East African countries. The national maps provide remarkable spatial resolution, thematic detail and geographical coverage. They may be applied in subsequent phases of tsetse and trypanosomiasis control projects, including the planning of entomological surveys, actual tsetse control operations and planning for land use in reclaimed areas. The methodology and datasets discussed in the paper may have applications beyond the tsetse and trypanosomiasis issue and may be used with reference to other arthropod vectors, vector-borne and parasitic diseases.

Pollinator attracting odour signals in sexually deceptive orchids of the Ophrys fusca group

We investigated patterns of volatiles of several allopatric and sympatric species of the Ophrys fusca group and one species of the O. mammosa/sphegodes group pollinated by either Andrena nigroaenea or A. flavipes, using electrophysiology (gas chromatography coupled with electroantennography; GC-EAD) and chemical analyses. We found 52 GC-EAD active compounds, mainly saturated and unsaturated hydrocarbons with chain lengths of 21 to 31, aldehydes, an ester, and an acid. Based on the relative proportions of all GC-EAD active compounds, the investigated species were compared using various statistical methods (ANOVA, principle component analyses, discriminant function analyses and cluster analyses). Our results show that Ophrys species with the same pollinator – independent of their phylogenetic relationship–use the same volatiles for pollinator attraction. Differences between the species mainly involve different quantitative patterns of volatiles. Our results are in congruence with previous studies that showed different odour bouquets to be responsible for the specific attraction of different pollinators and that alkanes and alkenes are most important for pollinator attraction.

Functional groups and patterns of organization in North American ant communities: a comparison with Australia

Ant distribution and behavioural dominance is examined at nine sites along an elevational gradient (1400–2600 m) in south eastern Arizona, in order to classify North American species according to a functional group scheme used extensively in Australia. The functional groups are then used as a basis for determining patterns of community structure along the environmental gradient, and for comparing community structure between Australia and North America. Quantitative information on species com‐ position was obtained from pitfall traps, and patterns of ant abundance at tuna baits were used to determine relative behavioural dominance among taxa. A total of eighty‐three species from twenty‐eight genera was recorded along the elevational gradient, with site species richness ranging from four (high elevation Douglas fir forest) to thirty‐three (mid elevation oak–juniper woodland). There was a strong correlation between ant abundance and richness, which was not an artefact of sampling intensity. The most common ants were species of Forelius, Monomorium, Crematogaster and Pheidole at the three desert sites, species of Formica, Pheidole and Crematogaster at the three woodland sites, and species of Prenolepis and Formica at one forest site. No species were abundant at two other forest sites. The most common species in traps also tended to be the most common species at baits. In terms of behavioural dominance, highly competitive ants included species of Solenopsis, Forelius, Monomorium and Liometopum. Species of Pheidole and Crematogaster tended to be moderately competitive, whereas species of Dory‐ myrmex, Myrmica, Camponotus and Formica (fusca gp) had low competitive ability. On the basis of these results and on published records of other taxa, North American ants were assigned to functional groups as follows (major taxa only given here): Dominant Dolichoderinae—Forelius, Liome‐ topum; Subordinate Camponotini—Camponotus; Hot Climate Specialists—Pogonomyrmex, Myrmecocystus; Cold Climate Specialists—Formica (rufa, exsecta and microgyna groups), Leptothorax, Stenamma, Lasius, Prenolepis; Cryptic Species—Smithistruma, Solenopsis (subgenus Diplorhop‐ trum), Acanthomyops; Opportunists—Formica (fusca group), Myrmica, Paratrechina, Dorymyrmex; Generalized Myr‐ micinae—Pheidole, Crematogaster, Monomorium; Specialist Predators—no major taxa. Functional group composition varied systematically along the elevation gradient: Dominant Dolichoderinae, Generalized MyrÍmicinae and Hot Climate Specialists were predominant at desert sites; Generalized Myrmicinae and Opportunists were predominant at woodland sites; and Opportunists and Cold Climate Specialists were predominant at forest sites. These patterns are consistent with published studies from elsewhere in North America. Almost all North American taxa can be matched with what appear to be ecologically equivalent taxa in Australia, and biogeographic patterns of functional group composition are broadly similar across the two continents. The major differences are that Australian ant communities are far richer in species, and are almost always dominated by dolichoderines, particularly species of Iridomyrmex. Generalized myrmicines are subdominant to dolichoderines in Australia, but are the behaviourally dominant ants throughout the warmer parts of North America. In cool‐temperate North America, species of Formica (especially rufa and exsecta groups) are behaviourally dominant, as they are throughout the Palearctic. Some major features of the North American fauna can be linked to its poor representation of Dominant Dolichoderinae, including (1) the relatively low degree of physiological, morphological and behavioural specialization of Hot Climate Specialists; (2) behavioural dominance by formicines in cool‐temperate habitats; and (3) the susceptibility to invasion by behaviourally dominant species such as the imported fire ant Solenopsis invicta and the Argentine ant Linepithema humile.

Functional morphology and anatomy of the polypneustic lobes of the last larval instar of tsetse flies, Glossina spp. (Diptera: Glossinidae)

This study examines the external and internal anatomy of the polypneustic (respiratory) lobes in 8 species of tsetse larvae (Diptera: Glossinidae). In the more primitive fusca group, the respiratory lobes are either ring-like ( Glossina longipennis) or partially divided into 2 lobes ( G. brevipalpis). Two distinctly separated lobes are present in the palpalis group ( G. palpalis, G. tachinoides, G. fuscipes) and in the morsitans group ( G. morsitans, G. pallidipes, G. austeni). Air enters the polypneustic lobes through narrow slits (stigmata) on the tips of numerous small spiracular papillae that are arranged in rows on both the outer and inner surfaces of the polypneustic lobes. The openings on the spiracular papillae connect to an air tube that is sculptured with septa and pegs. The air tubes connect to an outer air chamber that is likewise replete with a network of pegged septa. The outer air chamber is connected to a felt chamber containing a dense network of filamentous septa (spicules) that appear to function as an air filter. The felt chamber opens into a large, sculptured inner air chamber that connects directly to the regular tracheal trunk. The polypneustic lobes are unusually hard and brittle due to strong sclerotization of the cuticle and are permeated with numerous cuticular pores. There is no evidence that trichomes or other structures present on the respiratory lobes are innervated.

Succession, Forest Fragmentation, and the Distribution of Wood Ants

I tested the hypothesis that the distribution of territorial wood-ant species (Formica rufa group) of different colony structure and dispersal strategy relate differently to the dynamics and landscape structure of boreal forests. Monogynous species (colonies have only one queen and inhabit one nest) that disperse through nuptial flight and subsequent temporary nest parasitism, should primarily be found in young forests and in smaller old-forest fragments. These long-distance dispersers can reach these areas where the nests of F. fusca group ants (which the wood-ant queens invade and parasitize) are more common, and these wood-ant colonies can monopolize the small fragments. Polygynous species (colonies have many queens) that disperse mainly through nest budding and may form large colonies of cooperative nests, should primarily be found in old forests and larger old-forest fragments. In such patches these short-distance dispersers have enough space for developing into strong colonies capable of ruling out all other territorial species. I mapped the nests of eight territorial ant species, three of which belonged to the wood-ant group, in fragmented forests of different age in southern Finland. In general, the mapping data supported my hypotheses. The monogynous F. lugubris was more common in young forests and in small old-forest fragments than expected by chance. The polygynous F. aquilonia was more common in old forests and in larger old-forest fragments.

Genetic relationships and inferred evolutionary divergence in the New Zealand taxa of Nothofagus — Results from isozyme analysis

Genetic identity and standard genetic distance between the New Zealand taxa of Nothofagus, which are taxonomically distinguished at the subgeneric, specific, and varietal level, were derived from isozyme analysis of 22 gene loci. Average interpopulational genetic identities within and between the two recognised varieties of N. solandri are very similar and support their conspecific taxonomical status. Very high genetic identities, normally typical of conspecific plant populations, were also found between any two taxa of the 'fusca' group (subgenus Fuscospora), except for the pair N. truncata – N. solandri var. solandri (0.914). Average genetic identity between N. menziesii (subgenus Lophozonia) and all taxa of the 'fusca group is extremely low (0.060) and warrants the present subgeneric division. Inferred times of genetic divergence were compared with a small set of published data from amino acid sequencing of ribulose-1,s-bisphosphate carboxylase of some Nothofagus species. An ancient divergence of the two subgenera studied is implied, which reasonably matches late Cretaceous fossil records of the corresponding pollen types. A comparatively recent speciation, possibly during the late Pliocene to Pleistocene is assumed for the 'fusca' taxa.

Specificity in host choice by the slave-making antPolyergus rufescensLatr. (Hymenoptera Formicidae)

The interspecific relationships between the obligatory slave-making ant Polyergus rufescens and three host species belonging to the Formica fusca group (i.e. F. cunicularia, F. gagates, and F. rufibarbis) were analysed and quantified in the laboratory using an aggression test. Fierce and immediate attacks accompanied by the elements typical of overt aggression (i.e. gaster flexing, seizing, dragging, and carrying) characterized the encounters between P. rufescens and two of the host species: F. gagates (90%) and F. rufibarbis (95%). By contrast, only 9 (45%) pairs of slave-maker and F. cunicularia individuals fought and these encounters were always interrupted by mutual antennal inspections accompanied by the items of ritualized aggressive behaviour (i.e. threat and upright posture). The lower degree of aggression between P. rufescens and F. cunicularia compared with that occurring with the other two potential host species, could explain the presence of only F. cunicularia individuals as slaves in the nat...

Classification of tsetse flies Glossina spp. (Diptera: Glossinidae) by gas chromatographic analysis of cuticular components

AbstractGas liquid chromatography (GC) was used to analyse the cuticular alkanes of 26 species and subspecies of tsetse flies (Glossina spp.). Unique interspecific and intraspecific (males vs. females) chromatographic patterns were observed. Solvent extraction of dried museum specimens and fresh specimens were equally successful, and left specimens undamaged. GC peaks were used as characters with one of five character states per peak, to show phenetic relationships among species by sex using a UPGMA algorithm, using 23 peaks for males and 40 peaks for females. Comparisons among species of the morsitans group often agreed with recognized morsitans group classification using morphological techniques, with G. austeni Newstead being somewhat aberrant. Glossina tachinoides Westwood was less closely related to others in the palpalis group than previously described using morphology. Eleven members of the rarely studied fusca group were also classified by this methodology.

The distribution of Glossina species in Africa and their natural hosts

The distribution of 31 Glossina spp. and subspecies belonging to fusca, palpalis and morsitans groups is given for 38 African countries. The natural hosts of 17 tsetse species and subspecies from many areas within different regions of Africa are also given. These were collated from the results of both published and unpublished work, for the period 1953 to 1991 inclusive, comprising altogether 47, 697 bloodmeals. This review is aimed to provide current knowledge on the distribution as well as the natural hosts of tsetse.

A comparison of African Buffalo, N'Dama and Boran cattle as reservoirs of Trypanosoma vivax for different Glossina species

Teneral Glossina morsitans centralis were fed on the flanks of African buffalo, N'Dama or Boran cattle infected with Trypanosoma vivax IL 2337. The infected tsetse were maintained on goats and on day 25 after the infected feed, the surviving tsetse were dissected to determine the infection rates. The mean mature infection rates (% +/- S.E.) in the tsetse fed on buffalo, N'Dama and Boran cattle were 34.3 +/- 9.9, 33.7 +/- 13.4 and 58.9 +/- 7.1, respectively. Logistic regression analysis indicated that infection rates in the labrum and hypopharynx of the tsetse were significantly lower when fed on the infected buffalo or N'Dama than Boran cattle. Similarly, the risk of infection was significantly lower in male than female tsetse. When teneral G. m. centralis, G. pallidipes, G. p. gambiensis, G. brevipalpis and G. longipennis were fed simultaneously on either the buffalo cow, the N'Dama bull or the Boran steer infected with T. vivax IL 2337, the mature infection rates were higher in the two morsitans group than the two fusca group tsetse, whilst G. p. gambiensis was relatively refractory to the infection, irrespective of the host species on which they fed. Logistic regression analysis indicated that the infection rates in the labrum and hypopharynx were significantly different amongst the five tsetse species for each of the three infected host animals. Nevertheless, the trypanotolerant African buffalo and N'Dama cattle may serve as reservoirs of T. vivax infection as can trypanosusceptible Boran cattle.

Genetic variation in Glossina brevipalpis, G.longipennis and G.pallidipes, and the phenetic relationships of Glossina species

Glossina brevipalpis Newstead, G.longipennis Corti, and G.pallidipes Austen maintained at ILRAD, Nairobi, Kenya, were examined for genetic variation of fourteen enzyme loci, using polyacrylamide gel electrophoresis. G.brevipalpis had six polymorphic loci, an average of 1.46 effective alleles per locus and a mean heterozygosity per locus of 20.0 +/- 7.1%. The figures for the same parameters in G.longipennis were 3, 1.16 and 8.2 +/- 4.9%, and for G.pallidipes the figures were 7, 1.40 and 22.3 +/- 6.3%. Seven rare alleles were lost from the G.brevipalpis colony during a 1-year period, but no statistically significant changes were observed in the genetics of the colony during this period. Using allele frequency data for ten of the enzymes studied, and frequencies for these enzymes in other taxa, a phenogram was constructed that indicated that the subgenus Austenina (i.e. the fusca group) is the oldest of the three subgenera within the genus Glossina, and that the subgenus Glossina s.str. (i.e. the morsitans group) may be paraphyletic.

Glossina fusca group tsetse as vectors of cattle trypanosomiasis in Gabon and Zaire

1. The significance of Glossina fusca group tsetse flies as vectors of cattle trypanosomiasis was examined using biconical traps to survey tsetse populations at one site in Gabon and two sites in Zaire. 2. Mean trypanosome infection rates in G.tabaniformis Westwood over the study period ranged from a minimum of 8.9% at one site to a maximum of 17.7% at another. The mean infection rate in G.nashi Potts was 6.0%. 3. Up to 49% of bloodmeals of G.tabaniformis were from cattle. Trypanosome prevalence in cattle where G.tabaniformis appeared to be the main vector was 9.5% and 5.4% at the Mushie and OGAPROV ranches, respectively. 4. A highly significant positive correlation was found between tsetse challenge and trypanosome prevalence in N'Dama cattle across sites. Tsetse challenge was defined as the product of tsetse relative densities, trypanosome infection rates in the flies and the proportion of feeds taken by them from cattle. Thus, G.tabaniformis can be an important vector of pathogenic Trypanosoma species in cattle.

Large-scale rearing of Glossina longipennis in the laboratory

Glossina longipennis occurs in arid habitats of eastern Africa including Ethiopia, Kenya, Somalia, Uganda, Sudan and Tanzania (Ford and Katondo, 1977; Moloo, 1985). It feeds on a range of vertebrate hosts including man, warthog, giraffe, buffalo, elephant, rhinoceros, dog, cat, hyaena, aardvark and ostrich; but buffalo, elephant and rhinoceros are its favoured hosts (Weitz, 1963). It is a vector of animal trypanosomiasis and at Nguruman, Kenya, it showed a Trypanosoma congolense infection rate of 4.8% and a T. vivax infection rate of 2.4% (Owaga, 1981). However, very little research has been carried out on G. longipennis compared with other tsetse since it has not been previously colonized. One previous attempt to rear this tsetse species, using rabbits as hosts, was unsuccessful (Owaga, 1981). The reported reasons for the failure were: unsuccessful mating, high abortion rate and decreased pupal weight with successive generations. The present communication reports the successful largescale rearing of this fusca group tsetse species. Its colonization was aimed to provide material to investigate its vector competence for Trypanosoma vivax, T. congolense and T.b. brucei. In mid-1987, 48 wild females of G.longipennis were caught in Nguruman (1°50'S/36°05'E), Kenya, and were brought to the ILRAD Tsetse Vector Laboratory. They were kept in a climate controlled room at a temperature of 25 ± 0.5°C with a relative humidity of 80-85%. The tsetse were fed on the ears of lop-eared rabbits daily except at week-ends. A total of 174 pupae,. mean weight 79.5 ± 1.8 mg, were produced by these field-caught tsetse. Tsetse which emerged from these pupae formed the parental stock of the colony. The number of mated females in the colony increased and reached the target of 1500 breeding females in December 1988. The current rearing techniques follow. Adults and pupae are kept in a climate controlled room as above. Pupae are kept in lOx 40 x 40 cm emergence cages, up to 2000 pupae/cage. The newly emerged tsetse are immobilized at 2-3°C and sexed. The