Inventory of the caterpillars, their food plants and parasitoids began in 1978 for today's Area de Conservacion Guanacaste (ACG), in northwestern Costa Rica. This complex mosaic of 120 000 ha of conserved and regenerating dry, cloud and rain forest over 0-2000 m elevation contains at least 10 000 species of non-leaf-mining caterpillars used by more than 5000 species of parasitoids. Several hundred thousand specimens of ACG-reared adult Lepidoptera and parasitoids have been intensively and extensively studied morphologically by many taxonomists, including most of the co-authors. DNA barcoding -the use of a standardized short mitochondrial DNA sequence to identify specimens and flush out undisclosed species -was added to the taxonomic identification process in 2003.

The monophyly of the ichneumonid clade Pimpliformes is established and the phylogenetic relationships of the eight component subfamilies are resolved. The clade (Acaenitinae + (Diacritinae + (Cylloceriinae + (Diplazontinae + Orthocentrinae)))) is the sister‐lineage to the clade (Pimplinae + (Rhyssinae + Poemeniinae)). The Nearctic genus Cressonia Dasch is transferred to the Diacritinae from the Orthocentrinae. Tribes are not recognized in the Acaenitinae as the Coleocentrini (sensu Townes, 1971) is paraphyletic with respect to the Acaenitini. The Cylloceriinae is recognized as comprising three genera, Cylloceria Schiødte, Allomacrus Förster and Sweaterella gen.n. The Orthocentrinae, including the Helictinae of authors, is shown to be monophyletic, but the latter is clearly shown to be paraphyletic if the Orthocentrus genus‐group is excluded. The Pimplinae comprises four monophyletic tribes: the Delomeristini, consisting of Delomerista Förster and Atractogaster Kriechbaumer; the Perithoini trib.n., which includes only Perithous Holmgren (= Hybomischos Baltazar syn.n.); the Pimplini, which includes the Theronia genus‐group as well as the Pimpla genus‐group; and the Ephialtini, which includes the Polysphinctini syn.n., a monophyletic group that previously rendered the restricted Ephialtini paraphyletic. The tribe Delomeristini is the sister‐group to the clade (Ephialtini + (Perithoini + Pimplini)). The subfamily Poemeniinae is recognized as comprising three tribes: the Pseudorhyssini (trib.n.) which includes the single Holarctic genus Pseudorhyssa Merrill; the Rodrigamini (trib.n.) which includes only the Costa Rican genus Rodrigama Gauld; and the Poemeniini. The tribe Pseudorhyssini is the sister‐group to the clade (Rodrigamini + Poemeniini). The phylogenetic inter‐relationships of the genera of Poemeniini are resolved. A new genus from South Africa, Guptella (gen.n.) is described, and Achorocephalus Kriechbaumer is shown to be a synonym of Eugalta Cameron (syn.n.). The evolution of biological traits within the Pimpliformes is discussed with reference to the elucidated phylogeny, and zoogeographic patterns are outlined.

An ∼8400 cal yr record of vegetation change from the northern Peten, Guatemala, provides new insights into the environmental history of the archaeological area known as the Mirador Basin. Pollen, loss on ignition, and magnetic susceptibility analyses indicate warm and humid conditions in the early to mid-Holocene. Evidence for a decrease in forest cover around 4600 cal yr B.P. coincides with the first appearance of Zea mays pollen, suggesting that human activity was responsible. The period between 3450 cal yr B.P. and 1000 cal yr B.P. is characterized by a further decline in forest pollen types, includes an abrupt increase in weedy taxa, and exhibits the highest magnetic susceptibility values since the early Holocene, all of which suggest further agricultural disturbance in the watershed. A brief drop in disturbance indicators around 1800 cal yr B.P. may represent the Preclassic abandonment of the area. Changing pollen frequencies around 1000 cal yr B.P. indicate a cessation of human disturbance, which represents the Late Classic collapse of the southern Maya lowlands.

Archaeological and ecological investigations in the Mirador Basin of northern Guatemala have recovered archaeological, phytolith, palynological, and pedological data relevant to the early occupation and development of Maya civilization in a specific environmental matrix. Fluctuation in vegetation types as evident in cores and archaeological profiles suggest that the seasonally wet, forested bajo environment currently found in the northern Peten was anciently more of a perennially wet marsh system that may have been heavily used and influenced by large Preclassic occupations. Data suggest that climatic and environmental factors correspond with the cultural process in the Mirador Basin, and research in progress is oriented to further elucidating these issues.

A combined morphological and molecular phylogenetic analysis was performed to evaluate the subfamily relationships of the parasitoid wasp family Ichneumonidae (Hymenoptera). Data were obtained by coding 135 morphological and 6 biological characters for 131 exemplar species of ichneumonids and 3 species of Braconidae (the latter as outgroups). The species of ichneumonids represent all of the 42 currently recognized subfamilies. In addition, molecular sequence data (cytochrome oxidase I “DNA barcoding” region, the D2 region of 28S rDNA and part of the F2 copy of elongation factor 1-alpha) were obtained from specimens of the same species that were coded for morphology (1309 base pairs total). The data were analyzed using parsimony and Bayesian analyses. The parsimony analysis using all data recovered previously recognized informal subfamily groupings (Pimpliformes, Ophioniformes, Ichneumoniformes), although the relationships of these three groups to each other differed from previous studies and some of the subfamily relationships within these groupings had not previously been suggested. Specifically, Ophioniformes was the sister group to (Ichneumoniformes + Pimplformes), and Labeninae was placed near Ichneumoniformes, not as sister group to all Ichneumonidae except Xoridinae. The parsimony analysis using only morphological characters was poorly resolved and did not recover any of the three informal subfamily groupings and very few of the relationships were similar to the total-evidence parsimony analysis. The molecular-only parsimony analysis and both Bayesian analyses (total-evidence and molecular-only) recovered Pimpliformes, a restricted Ichneumoniformes grouping and many of the subfamily groupings recovered in the total-evidence parsimony analysis. A comparison and discussion of the results obtained by each phylogenetic method and different data sets is provided. It is concluded that the molecular characters produced results that were relatively consistent with traditional, non-phylogenetic concepts of relationships between the ichneumonid subfamilies, whereas the morphological characters did not (at least not by themselves). The inclusion of both molecular and morphological characters using parsimony produced a topology that was the closest to the traditional subfamily relationships. The method of analysis did not greatly affect the overall topology for the molecular-only analyses, but there were differences between Bayesian and parsimony results for the total-evidence analyses (especially near the root of the tree). The Bayesian results did not seem to be altered very much by the inclusion of morphological characters, unlike in the parsimony analysis. In summary, the following groups were supported in multiple analyses regardless of the characters used or method of tree-building: Pimpliformes, higher Ophioniformes, higher Pimpliformes, (Claseinae + Pedunculinae), (Banchinae + Stilbopinae), Campopleginae, Cremastinae, Diplazontinae, Ichneumoninae (including Alomya), Labeninae, Ophioninae, Poemeniinae, Rhyssinae, and Tersilochinae sensu stricto. Conversely, Ctenopelmatinae and Tryphoninae were never recovered without inclusion of other taxa. Based on the hypothesis of relationships obtained by the total-evidence parsimony analysis, the following formal taxonomic changes are proposed: Alomyinae Förster (= Alomya Panzer and Megalomya Uchida) is once again synonymized with Ichneumoninae and is now considered a tribe (Alomyinirev. stat.); and Notostilbops Townes is transferred from Stilbopinae to Banchinae, tribe Atrophini.