Abstract. 1. For the first time, long-term changes in total aerial insect biomass have been estimated for a wide area of Southern Britain.2. Various indices of biomass were created for standardised samples from four of the Rothamsted Insect Survey 12.2 m tall suction traps for the 30 years from 1973 to 2002.3. There was a significant decline in total biomass at Hereford but not at three other sites: Rothamsted, Starcross and Wye.4. For the Hereford samples, many insects were identified at least to order level, some to family or species level. These samples were then used to investigate the taxa involved in the decline in biomass at Hereford.5. The Hereford samples were dominated by large Diptera, particularly Dilophus febrilis, which showed a significant decline in abundance.6. Changes in agricultural practice that could have contributed to the observed declines are discussed, as are potential implications for farmland birds, with suggestions for further work to investigate both cause and effect.

No abstract

Societal Impact StatementWe found evidence that larger fruited plant species are more likely to be found in aseasonal wet areas of Malesia. These areas are likely to be impacted by increasing human encroachment, which threatens both large‐fruited species and the large fauna that are most likely responsible for their dispersal. This synergistic threat could drive the loss of fruit‐crop relatives that potentially have key traits for resilient fruit crops of the future.Summary It is unclear how fruit size determines distributions of megadiverse tropical flora. Energetic constraints of ecosystems suggest plant species with larger fruit should be found in the higher productivity, aseasonal wet tropics. However, the probability of seed dispersal over large scales should be increased by fruits being smaller, due to being available to a greater number of dispersal agents. We use a Bayesian phylogenetic model of species occurrence for >3400 species in Malesia to test how fruit size and environment interact to determine species distributions across the archipelago. We show that larger fruited species are more likely to occur in aseasonal wet areas. We also found that smaller fruit size was associated with species occurrence in more mountainous areas. Fruit size interacts with environmental variables to shape plant distributions across the megadiverse Malesian islands. The evolutionary processes that influence the patterns we have observed require further examination.

Fruit morphology and the anatomical structure of the pericarp, fruiting perianth, and seed coat were studied in 15 species of Poikilospermum, a genus whose position within the Urticaceae has long been controversial. Possible evolutionary trends of their transformation are suggested for both subgenera; plesiomorphies were found in P. oblongifolium and P. scabrinervium. Structural peculiarities of the fruit connected with its ejection out of the tubular perianth are discussed. The archaism of the fruit in Poikilospermum is revealed, indicated, as in Boehmeria, by the presence of the rudiment of an aborted carpel in the form of a large two-lobed rib. Using carpological anatomical characters, the species studied are classified into informal groups, such characters being able to pull the species within the subgenera into rough groupings where gross morphology has been unable to do so. It is shown that heterobathmy may be strongly associated with the genus Poikilospermum. Each subgenus has its own set of primitive carpological characters: in subgenus Poikilospermum the absence of a fruiting perianth which encases the fruit, and also of capitate inflorescences with swollen receptacles; in subgenus Ligulistigma remnant rudiment of the second carpel and ovary loculus, as well as a primitive, less simplified seed coat. Though the position of Poikilospermum as indicated by molecular data is within Urera, our results suggest that Dendrocnide (the only genus of the Urticeae that has a pyrenarium fruit type) may be closest to Poikilospermum, although the pericarp structure and dissemination behaviour in Poikilospermum are more specialised than those exhibited by Dendrocnide. Seed coat structure is also shown to exhibit traits seen in Moraceae.