What Goes in Must Come Out? The Metabolic Profile of Plants and Caterpillars, Frass, And Adults of Asota (Erebidae: Aganainae) Feeding on Ficus (Moraceae) in New Guinea.

Insect herbivores have evolved a broad spectrum of adaptations in response to the diversity of chemical defences employed by plants. Here we focus on two species of New Guinean Asota and determine how these specialist moths deal with the leaf alkaloids of their fig (Ficus) hosts. As each focal Asota species is restricted to one of three chemically distinct species of Ficus, we also test whether these specialized interactions lead to similar alkaloid profiles in both Asota species. We reared Asota caterpillars on their respective Ficus hosts in natural conditions and analyzed the alkaloid profiles of leaf, frass, caterpillar, and adult moth samples using UHPLC-MS/MS analyses. We identified 43 alkaloids in our samples. Leaf alkaloids showed various fates. Some were excreted in frass or found in caterpillars and adult moths. We also found two apparently novel indole alkaloids-likely synthesized de novo by the moths or their microbiota-in both caterpillar and adult tissue but not in leaves or frass. Overall, alkaloids unique or largely restricted to insect tissue were shared across moth species despite feeding on different hosts. This indicates that a limited number of plant compounds have a direct ecological function that is conserved among the studied species. Our results provide evidence for the importance of phytochemistry and metabolic strategies in the formation of plant-insect interactions and food webs in general. Furthermore, we provide a new potential example of insects acquiring chemicals for their benefit in an ecologically relevant insect genus.

Reduced body sizes in climate-impacted Borneo moth assemblages are primarily explained by range shifts.

Both community composition changes due to species redistribution and within-species size shifts may alter body-size structures under climate warming. Here we assess the relative contribution of these processes in community-level body-size changes in tropical moth assemblages that moved uphill during a period of warming. Based on resurvey data for seven assemblages of geometrid moths (>8000 individuals) on Mt. Kinabalu, Borneo, in 1965 and 2007, we show significant wing-length reduction (mean shrinkage of 1.3% per species). Range shifts explain most size restructuring, due to uphill shifts of relatively small species, especially at high elevations. Overall, mean forewing length shrank by ca. 5%, much of which is accounted for by species range boundary shifts (3.9%), followed by within-boundary distribution changes (0.5%), and within-species size shrinkage (0.6%). We conclude that the effects of range shifting predominate, but considering species physiological responses is also important for understanding community size reorganization under climate warming.

Variably hungry caterpillars: predictive models and foliar chemistry suggest how to eat a rainforest.

A long-term goal in evolutionary ecology is to explain the incredible diversity of insect herbivores and patterns of host plant use in speciose groups like tropical Lepidoptera. Here, we used standardized food-web data, multigene phylogenies of both trophic levels and plant chemistry data to model interactions between Lepidoptera larvae (caterpillars) from two lineages (Geometridae and Pyraloidea) and plants in a species-rich lowland rainforest in New Guinea. Model parameters were used to make and test blind predictions for two hectares of an exhaustively sampled forest. For pyraloids, we relied on phylogeny alone and predicted 54% of species-level interactions, translating to 79% of all trophic links for individual insects, by sampling insects from only 15% of local woody plant diversity. The phylogenetic distribution of host-plant associations in polyphagous geometrids was less conserved, reducing accuracy. In a truly quantitative food web, only 40% of pair-wise interactions were described correctly in geometrids. Polyphenol oxidative activity (but not protein precipitation capacity) was important for understanding the occurrence of geometrids (but not pyraloids) across their hosts. When both foliar chemistry and plant phylogeny were included, we predicted geometrid-plant occurrence with 89% concordance. Such models help to test macroevolutionary hypotheses at the community level.

Polyphagy and diversification in tussock moths: Support for the oscillation hypothesis from extreme generalists.

Theory on plasticity driving speciation, as applied to insect-plant interactions (the oscillation hypothesis), predicts more species in clades with higher diversity of host use, all else being equal. Previous support comes mainly from specialized herbivores such as butterflies, and plasticity theory suggests that there may be an upper host range limit where host diversity no longer promotes diversification. The tussock moths (Erebidae: Lymantriinae) are known for extreme levels of polyphagy. We demonstrate that this system is also very different from butterflies in terms of phylogenetic signal for polyphagy and for use of specific host orders. Yet we found support for the generality of the oscillation hypothesis, in that clades with higher diversity of host use were found to contain more species. These clades also consistently contained the most polyphagous single species. Comparing host use in Lymantriinae with related taxa shows that the taxon indeed stands out in terms of the frequency of polyphagous species. Comparative evidence suggests that this is most probably due to its nonfeeding adults, with polyphagy being part of a resulting life history syndrome. Our results indicate that even high levels of plasticity can drive diversification, at least when the levels oscillate over time.

Calibrating the taxonomy of a megadiverse insect family: 3000 DNA barcodes from geometrid type specimens (Lepidoptera, Geometridae).

It is essential that any DNA barcode reference library be based upon correctly identified specimens. The Barcode of Life Data Systems (BOLD) requires information such as images, geo-referencing, and details on the museum holding the voucher specimen for each barcode record to aid recognition of potential misidentifications. Nevertheless, there are misidentifications and incomplete identifications (e.g., to a genus or family) on BOLD, mainly for species from tropical regions. Unfortunately, experts are often unavailable to correct taxonomic assignments due to time constraints and the lack of specialists for many groups and regions. However, considerable progress could be made if barcode records were available for all type specimens. As a result of recent improvements in analytical protocols, it is now possible to recover barcode sequences from museum specimens that date to the start of taxonomic work in the 18th century. The present study discusses success in the recovery of DNA barcode sequences from 2805 type specimens of geometrid moths which represent 1965 species, corresponding to about 9% of the 23 000 described species in this family worldwide and including 1875 taxa represented by name-bearing types. Sequencing success was high (73% of specimens), even for specimens that were more than a century old. Several case studies are discussed to show the efficiency, reliability, and sustainability of this approach.

Molecular phylogeny of Lymantriinae (Lepidoptera, Noctuoidea, Erebidae) inferred from eight gene regions.

To understand the evolutionary history of Lymantriinae and test the present higher-level classification, we performed the first broad-scale molecular phylogenetic analysis of the subfamily, based on 154 exemplars representing all recognized tribes and drawn from all major biogeographical regions. We used two mitochondrial genes (cytochrome c oxidase subunit I and 16S ribosomal RNA) and six nuclear genes (elongation factor-1α, carbamoylphosphate synthase domain protein, ribosomal protein S5, cytosolic malate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase and wingless). Data matrices (in total 5424 bp) were analysed by parsimony and model-based evolutionary methods (maximum likelihood and Bayesian inference). Based on the results of the analyses, we present a new phylogenetic classification for Lymantriinae composed of seven well-supported tribes, two of which are proposed here as new: Arctornithini, Leucomini, Lymantriini, Orgyiini, Nygmiini, Daplasini trib. nov. and Locharnini trib. nov. We discuss the internal structure of each of these tribes and address some of the more complex problems with the genus-level classification, particularly within Orgyiini and Nygmiini.

Major lineages of Nolidae (Lepidoptera, Noctuoidea) elucidated by molecular phylogenetics.

To elucidate the evolutionary relationships of the major lineages within the moth family Nolidae, we analysed a molecular dataset comprising eight independent gene regions (6.4 kbp), cytochrome c oxidase subunit I (COI) from the mitochondrial genome, and elongation factor-1α (EF-1α), ribosomal protein S5 (RpS5), carbamoylphosphate synthase domain protein (CAD), cytosolic malate dehydrogenase (MDH), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), isocitrate dehydrogenase (IDH) and wingless genes from the nuclear genome, using parsimony and model-based evolutionary methods (maximum likelihood and Bayesian inference). Our analyses revealed a well-resolved phylogenetic hypothesis, again recovering the six previously recognized families within Noctuoidea (i.e. Oenosandridae, Notodontidae, Euteliidae, Erebidae, Nolidae and Noctuidae), and monophyly of the quadrifid Noctuoidea (i.e. Euteliidae, Erebidae, Nolidae and Noctuidae). The family Nolidae is diagnosed and characterized by two synapomorphies from morphology: construction of a ridged boat-shaped cocoon that bears a vertical exit slit at one end; and two other morphological character states: elongation of the forewing retinaculum into a bar-like or digitate condition and possession of a postpiracular counter-tympanal hood. We present a new phylogenetic hypothesis for Nolidae consisting of eight strongly supported subfamilies, two of which are erected here: Diphtherinae, Risobinae, Collomeninae subfam. nov., Beaninae subfam. nov., Eligminae, Westermanniinae, Nolinae and Chloephorinae. Where we are able, each monophyletic lineage is diagnosed by morphological autapomorphies and within each subfamily, monophyletic tribes and subtribes are circumscribed, most of which are also diagnosable by morphological apomorphies. We also describe two new taxa: Gelastocerini trib. nov. and Etannina subtrib. nov. The Neotropical subfamily Diphtherinae, here newly circumscribed, is considered to be the plesiomorphic sister lineage to the rest of Nolidae. Diphtherinae are characterized by loss of the proximal pair of metatibial spurs in males and by the presence of a frontal tubercle, which is presumably associated with a derived strategy of emergence from the cocoon.

Diversity partitioning confirms the importance of beta components in tropical rainforest Lepidoptera.

Tropical beta diversity, and particularly that of herbivorous insects in rainforests, is often considered to be enormous, but this notion has recently been challenged. Because tropical beta diversity is highly relevant to our view on biodiversity, it is important to gain more insights and to resolve methodological problems that may lead to contradictions in different studies. We used data on two ecologically distinct moth families from Southeast Asia and analyzed separately the contribution of beta components to overall species richness at three spatial scales. Observed diversity partitions were compared under different types of null models. We found that alpha diversity was lower than expected on the basis of null models, whereas hierarchical beta components were larger than expected. Beta components played a significant role in shaping gamma diversity, and their contribution can be high (multiplicative beta >5). We found a reduction in beta components when comparing primary forests to agricultural sites (cf. "biotic homogenization"), but even in these habitats, beta components were still substantial. Our analyses show that beta components do play an important role in our data on tropical herbivorous insects and that these results are not attributable to lumping different habitats when sampling environmental gradients.

Elevation increases in moth assemblages over 42 years on a tropical mountain.

Physiological research suggests that tropical insects are particularly sensitive to temperature, but information on their responses to climate change has been lacking-even though the majority of all terrestrial species are insects and their diversity is concentrated in the tropics. Here, we provide evidence that tropical insect species have already undertaken altitude increases, confirming the global reach of climate change impacts on biodiversity. In 2007, we repeated a historical altitudinal transect, originally carried out in 1965 on Mount Kinabalu in Borneo, sampling 6 moth assemblages between 1,885 and 3,675 m elevation. We estimate that the average altitudes of individuals of 102 montane moth species, in the family Geometridae, increased by a mean of 67 m over the 42 years. Our findings indicate that tropical species are likely to be as sensitive as temperate species to climate warming, and we urge ecologists to seek other historic tropical samples to carry out similar repeat surveys. These observed changes, in combination with the high diversity and thermal sensitivity of insects, suggest that large numbers of tropical insect species could be affected by climate warming. As the highest mountain in one of the most biodiverse regions of the world, Mount Kinabalu is a globally important refuge for terrestrial species that become restricted to high altitudes by climate warming.