Larval parasitism in a specialist herbivore is explained by phenological synchrony and host plant availability.

Parasitism is a key factor in the population dynamics of many herbivorous insects, although its impact on host populations varies widely, for instance, along latitudinal and altitudinal gradients. Understanding the sources of geographical variation in host-parasitoid interactions is crucial for reliably predicting the future success of the interacting species under a context of global change. Here, we examine larval parasitism in the butterfly Aglais urticae in south-west Europe, where it is a mountain specialist. Larval nests were sampled over 2 years along altitudinal gradients in three Iberian mountain ranges, including the Sierra Nevada, home to its southernmost European population. Additional data on nettle condition and adult butterflies were obtained in the study areas. These data sources were used to investigate whether or not differences in parasitism rates are related to the geographical position and phenology of the host, and to the availability of the host plants. Phenological differences in the host populations between regions were related to the severity of summer drought and the corresponding differences in host plant availability. At the trailing-edge of its distribution, the butterfly's breeding season was restricted to the end of winter and spring, while in its northern Iberian range the season was prolonged until mid-summer. Although parasitism was an important source of mortality in all regions, parasitism rates and parasitoid richness were highest in the north and lowest in the south. Moreover, within a region, there was a notable increase in parasitism rates over time, which probably led to selection against an additional late summer host generation in northern regions. Conversely, the shorter breeding season in Sierra Nevada resulted in a loss of synchrony between the host and one important late season parasitoid, Sturmia bella, which may partly explain the high density of this butterfly species at the trailing-edge of its range. Our results support the key role of host phenology in accounting for differences in parasitism rates between populations. They also provide insights into how climate through host plant availability affects host phenology and, ultimately, the impact of parasitism on host populations.

Nematocera flies recorded in Serra do Courel, northwest Spain, May 2012 (Diptera: Anisopodidae, Blepharoceridae, Cylindrotomidae, Limoniidae, Pediciidae, Tipulidae and Trichoceridae) including descriptions of two new species of Limoniidae.

During May 2012 Diptera were sampled in the Serro do Courel area of Lugo Province, Galicia, northwest Spain. The authors of this paper, members of the Malloch Society (see website) are active in attempting to understand the detailed ecology of flies. Much of this work is through targeting larval stages often with an emphasis on saproxylic situations. By rearing adults from larvae direct relationships between them and their detailed habitat requirements are established. The list of nematocerous Diptera that were sampled includes 36 species two of them new to science and records of six others new to the Iberian peninsula are provided. We describe Lipsothrix galiciensis Hancock & Hewitt sp. nov., and Prionolabis pjotri Hancock sp. nov. of the family Limoniidae and provide a key to adults of European Lipsothrix species. Such results from this brief opportunity indicate the potential of the area for further field work in these and other families of Diptera. 

The syrphids of Serra do Courel, Northern Spain and description of a new Cheilosia Meigen species (Diptera: Syrphidae).

The syrphids (Syrphidae) of Serra do Courel, a mountainous locality of just over 20,000ha at the west end of the Cantabrian Mountains, northern Spain are poorly known. The Scottish based, Malloch Society visited the locality in May 2012 and collected a total of 462 specimens of 98 syrphid species and 36 genera. These represent the first syrphid records from Serra do Courel. The area has many meadows and small woodlands or 'soutos' and these habitats combined were the most productive, 69 spp. recorded. Cheilosia lucense Ricarte sp. nov. is described from Courel and compared with other species of the alpina group. Six other syrphid species were new to the Iberian Peninsula, three of which belong to the saproxylic genus, Brachyopa. In common with studies elsewhere in the Cantabrian Mountains, Cheilosia was the most diverse genus and 21 species were recorded. The syrphid fauna of the Cantabrian Mountains includes 203 species of which 24 are here added and a species checklist provided. 

Development sites and early stages of eleven species of Clusiidae (Diptera) occurring in Europe.

Two hundred and ninety-six rearing records of 11 clusiid species (Diptera, Clusiidae) were obtained from 8 tree species in England, Finland, France, Norway, Russia and Scotland, mainly during the period 1994 to 2004. Larvae and puparia were found between annual layers of whitewood (sapwood and heartwood) of wet, decay-softened, dead wood. Levels of host tree specificity were low, most species were reared from 2-4 host trees, maximum 6. The clusiid larva is distinguished by: a small, translucent head skeleton with an obliquely-shaped apex to the artium; a pseudocephalon fixed in an inverted position except for an external, flattened section bearing the antennomaxillary organs; a spherical prothorax with a truncate rim embedded with sensilla and, a wedge-shaped anal segment bearing a pair of conspicuous, sclerotised, red-brown hooks on the inner margins of which are the posterior spiracular plates. Many of these features support a distinctive feeding mechanism, spot-sucking of biofilm coating wet, decaying whitewood. Early stage characters support the results of recent supraspecific taxonomic and systematic investigations, such as the synonymy of Paraclusia Czerny under Clusia Haliday and the recognition of species groups in Clusiodes Coquillett. Based on early stages, supraspecific clusiid taxa are easily recognised but at species level, differences are relatively fine-grained and minor. A key is provided to identify puparia of species reared in this study.