The reproductive biology and diapause of the British fungal-breeding Drosophila

Abstract.

• 1 Seasonal reproductive development was investigated in four obligate fungivorous species, D.phalerata Meigen, D.transversa Fallen, D.cameraria Haliday and D.confusa Staeger.
• 2 Samples of females taken from woodlands over a 2 year period were scored for reproductive status and fat content.
• 3 Populations of D.phalerata and D.cameraria maintained in an outdoor insectary provided information on developmental time and adult mortality throughout the year.
• 4 Experiments in controlled environmental chambers gave percentage diapause curves against day length for all four species.
• 5 In D.phalerata the influence of temperature and fungus upon diapause behaviour was also investigated.
• 6 In D.phalerata the optimal strategy for reproductive development can vary from month to month. Maturation of females may be immediate, dependent upon a fungal cue or completely prevented.

     

The British species of Achrysocharoides (Hymenoptera, Eulophidae)

Abstract. Taxonomic notes and a key are provided for the eleven species of Achrysocharoides found in Britain including A.carpini sp.n. Several forms of undetermined specific status are also described. Two species-groups are erected: the latreillii group and the aty s group. All British species have been reared as parasites only of leaf-mining larval Gracillariidae (Lepidoptera); one brood is here recorded from Caloptilia on Quercus; all other rearings are from Phyllono-rycter species. Parasite—host associations and speciation within the genus are discussed.     

A Paleocene coral—algal—sponge reef from southwestern Alabama and the ecology of Early Tertiary reefs

The Late Paleocene Salt Mountain Limestone from southwestern Alabama is a coral-algal-sponge buildup which further characterizes the faunal makeup of early post-Cretaceous reefs. Thin sectioning has disclosed a variety of lithologies, including large foram-algal packstone, algal bindstone, and sponge bafflestone. A low-diversity fauna of massive scleractinian corals caps the sequence, but may be developed intermittently throughout the section as well. The constructional importance of coralline algae and the low diversity of scleractinian corals are characteristic of Paleocene reefs in general. Sponges, however, are virtually unknown in earliest Tertiary sediments. Their abundance in the Salt Mountain demonstrates not only their local contribution to Early Tertiary reefs, but may also reflect an opportunistic response of sponges as reef constructors following the extinction of oligotrophic, rudist-coral reef communities of the Late Cretaceous. □ Paleocene, reef, paleoecology, sponges, extinction.     

Phylogeny of the bee family Melittidae (Hymenoptera: Anthophila) based on combined molecular and morphological data

The bee family Melittidae comprises a small, but biologically fascinating, group of mostly oligolectic bees, some of which are oil collecting. Phylogenetic relationships within this family are poorly understood and some genera cannot be placed with confidence at the subfamily level. We analysed melittid phylogeny using a combined dataset of five nuclear genes [28S, elongation factor‐1α (EF‐1α, F2 copy), long‐wavelength rhodopsin, Na‐K ATPase and RNA polymerase II] spanning 4842 bp plus 68 adult morphological characters. Our study included 25% of the species‐level diversity and 81% of the generic‐level diversity and included all previously recognized tribes and subfamilies. We analysed the dataset using parsimony, maximum likelihood and Bayesian methods. All methods yielded congruent results. All topologies recovered the three previously recognized subfamilies (Dasypodainae, Melittinae, Meganomiinae), but two genera (Afrodasypoda and Promelitta) are transferred from Dasypodainae to Melittinae. On the basis of our tree topologies we identify four tribes (Dasypodaini comb.n. , Hesperapini stat.n. , Macropidini comb.n. and Melittini), only one of which (Melittini) matches a widely used classification. Lastly, we discuss the evolution of host‐plant association in the light of our new phylogenetic hypothesis. Our results strongly support multiple independent origins of oil‐collecting behaviour in the Melittinae.     

The responses of polyphagous predators to prey spatial heterogeneity: aggregation by carabid and staphylinid beetles to their cereal aphid prey

Abstract. 1. Discrete patches of aphids were artificially created in winter wheat fields in 1982 and in 1983 using field cages.
2. Aggregation by polyphagous predators at these patches following cage removal was measured using pitfall traps in patch and control areas.
3. Several species of polyphagous beetle (Carabidae and Staphylinidae) aggregated in these patches while other species did not.
4. The consequences of aggregation by polyphagous predators to a single prey species are discussed.