No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

The study of Neuropterida from the Lower Cretaceous Purbeck Limestone Group and Wealden Supergroup of southern England has shown that 13 families, 24 genera and 33 species are present. The majority of the taxa described are new to science with the exception of six genera and four species, which are redescribed. The Purbeck fauna consists of the families Kailligrammatidae, Psychopsidae, Osmylidae, Prohemerobiidae, Chrysopidae, ?Hemerobiidae, Berothidae, Nymphidae, Mesoraphidiidae and one incertae sedis family. The Wealden contains Kalligrammatidae, Psychopsidae, Osmylidae, Ithonidae, Mesoraphidiidae and two incertae sedis families. The psychopsoid families are the most dominant neuropterid in the Purbeck and Wealden neuropterid fauna. The discovery of the families Chrysopidae, ?Hemerobiidae, Osmylidae, Ithonidae, Berothidae represent the first record in the Mesozoic of Britain. The ithonid also represents the oldest fossil record of that family. Megaloptera have not been found in these deposits. The neuropterids in both deposits would have lived in a distant wooded area based on modern analogues. On death they would have undergone disarticulation, decomposition/sorting and then deposition of wings only in the depositional basin. No body parts have been found associated with any neuropterid from these deposits. The climate change through the English Lower Cretaceous may have affected the neuropterid fauna in size (Raphidioptera) and family turnover (Neuroptera). Biogeographical links have been hinted at with Asia and South America with the occurrence of some of the same genera. A preliminary key to the fossil raphidiopterans has been presented aiding identification to family and generic level. This is the first time such a key has been presented on fossil Raphidioptera. A cladistic study was undertaken (21 characters and 28 taxa) on the genera of fossil Raphidioptera with the inclusion of extant genera. Fifteen synapomorphies were found, but, relationships are largely unresolved, with few well-supported clades. Baissopteridae and Mesoraphidiidae were found to be paraphyletic. Baissopteridae is basal to all raphidiopterans. Both the key and cladistic study highlighted the need for a major taxonomic revision of fossil raphidiopterans.

No description available.

The stadia of the life cycle, age at oviposition, frequency of oviposition and fecundity of parthenogenetic individuals of Folsomia distincta are recorded. Notes on the behaviour of this species are given particularly in relation to the formation of groups. Semi-permanent social aggregations are formed and maintained by an olfactory stimulation from the animal or a secretion from them, especially by the fourth and fifth instars. The relationship between the mean individual fecundity of cultures of F. distincta and the mean area available per individual is given. Both the individual fecundity and the number of individuals ovipositing is reduced by disturbances whilst ovipositing or feeding. The population levels of F. distincta, Isotomina thermophila F. nana and Isotoma notabilis in a meadow are recorded for two years. The greater ability of F. nana and I. notabilis to withstand drought is noted. The differences in population at the different stations were most easily explained by the exposure of the station to the climate. The concept of aggregation under natural conditions is discussed. The aggregation of the four species is compared and it is shown that young and old individuals of the same species are equally aggregated. The relationship between the environment and microdistribution of each species is investigated. It is noted that the position of young individuals may be due to physical conditions and that the older individuals tend to form social aggregations.

An area of rough pastureland has been sampled regularly for Lasius flavus and other soil animals for three years. The density of ants found in these nests agrees well with estimates of other workers using mature nests from undisturbed sites. The abundance of ants in the surface 10cm of the nest was correlated with twenty biotic and abiotic measurements to see which factors most heavily influenced ant captures. It was found that the model: Ant = 17494 x larval brood dry biomass (g) activity + 10654 x adult reproductives dry biomass (g) + 0.1 x base area of nest mound (sq.cm) + c could predict the trends in ant activity with high accuracy (0.0001 < p < 0.002).The relationship of subterranean aphids to ants was also investigated. Generally there were positive associations between Lasius flavus and regularly tended root aphids; but species which show obligatory host alternation e.g. Anoecia corni and aphids which are not ant tended e.g. Aploneura lentisci show marked negative associations with Lasius flavus. During periods of high larval biomass, the number of adult aphids was practically unchanged, although many first instar aphids vanished from the nest, presumably due to predation. Only when the alate ants emerged were aphid numbers drastically reduced. This was attributed to the feeding up of the new queens, which subsequently fast until the development of their first brood. Despite the fluctuation of aphid numbers, no deliberate form of regulation by ants could be shown. The distribution of aphids within the nest was studied and clump sizes for aphid species were calculated. These varied with sub-family, and showed that for most of the year different species intermingled within the nest, not forming separate mosaics. At high aphid density however, it was found that different aphid species became most abundant in certain parts of the nest; those most heavily sclerotized/waxy still possessing rudimentary siphuncles, furthest from the nest centre, and those without siphuncles and some with legs adapted for ant 'communication' near the centre of the nest. This is related to the degree of ant attendance towards each aphid.