Parallel evolution of Bacillus thuringiensis toxin resistance in lepidoptera

Despite the prominent and worldwide use of Bacillus thuringiensis (Bt) insecticidal toxins in agriculture, knowledge of the mechanism by which they kill pests remains incomplete. Here we report genetic mapping of a membrane transporter (ABCC2) to a locus controlling Bt Cry1Ac toxin resistance in two lepidopterans, implying that this protein plays a critical role in Bt function.

Assessing the value of DNA barcodes for molecular phylogenetics: effect of increased taxon sampling in lepidoptera

BACKGROUND

A common perception is that DNA barcode datamatrices have limited phylogenetic signal due to the small number of characters available per taxon. However, another school of thought suggests that the massively increased taxon sampling afforded through the use of DNA barcodes may considerably increase the phylogenetic signal present in a datamatrix. Here I test this hypothesis using a large dataset of macrolepidopteran DNA barcodes.

METHODOLOGY/PRINCIPAL FINDINGS

Taxon sampling was systematically increased in datamatrices containing macrolepidopteran DNA barcodes. Sixteen family groups were designated as concordance groups and two quantitative measures; the taxon consistency index and the taxon retention index, were used to assess any changes in phylogenetic signal as a result of the increase in taxon sampling. DNA barcodes alone, even with maximal taxon sampling (500 species per family), were not sufficient to reconstruct monophyly of families and increased taxon sampling generally increased the number of clades formed per family. However, the scores indicated a similar level of taxon retention (species from a family clustering together) in the cladograms as the number of species included in the datamatrix was increased, suggesting substantial phylogenetic signal below the 'family' branch.

CONCLUSIONS/SIGNIFICANCE

The development of supermatrix, supertree or constrained tree approaches could enable the exploitation of the massive taxon sampling afforded through DNA barcodes for phylogenetics, connecting the twigs resolved by barcodes to the deep branches resolved through phylogenomics.

The evolution of a female genital trait widely distributed in the Lepidoptera: comparative evidence for an effect of sexual coevolution

BACKGROUND

Sexual coevolution is considered responsible for the evolution of many male genital traits, but its effect on female genital morphology is poorly understood. In many lepidopterans, females become temporarily unreceptive after mating and the length of this refractory period is inversely related to the amount of spermatophore remaining in their genital tracts. Sperm competition can select for males that delay female remating by transferring spermatophores with thick spermatophore envelopes that take more time to be broken. These envelopes could select for signa, sclerotized sharp structures located within the female genital tract, that are used for breaking spermatophores. Thus, this hypothesis predicts that thick spermatophore envelopes and signa evolve in polyandrous species, and that these adaptations are lost when monandry evolves subsequently. Here we test the expected associations between female mating pattern and presence/absence of signa, and review the scant information available on the thickness of spermatophore envelopes.

METHODOLOGY/PRINCIPAL FINDINGS

We made a literature review and found information on female mating pattern (monandry/polyandry), presence/absence of signa and phylogenetic position for 37 taxa. We built a phylogenetic supertree for these taxa, mapped both traits on it, and tested for the predicted association by using Pagel's test for correlated evolution. We found that, as predicted by our hypothesis, monandry evolved eight times and in five of them signa were lost; preliminary evidence suggests that at least in two of the three exceptions males imposed monandry on females by means of specially thick spermatophore envelopes. Previously published data on six genera of Papilionidae is in agreement with the predicted associations between mating pattern and the characteristics of spermatophore envelopes and signa.

CONCLUSIONS/SIGNIFICANCE

Our results support the hypothesis that signa are a product of sexually antagonistic coevolution with spermatophore envelopes.

Joining inventory by parataxonomists with DNA barcoding of a large complex tropical conserved wildland in northwestern Costa Rica

Background

The many components of conservation through biodiversity development of a large complex tropical wildland, Area de Conservacion Guanacaste (ACG), thrive on knowing what is its biodiversity and natural history. For 32 years a growing team of Costa Rican parataxonomists has conducted biodiversity inventory of ACG caterpillars, their food plants, and their parasitoids. In 2003, DNA barcoding was added to the inventory process.

Methodology/Principal Findings

We describe some of the salient consequences for the parataxonomists of barcoding becoming part of a field biodiversity inventory process that has centuries of tradition. From the barcoding results, the parataxonomists, as well as other downstream users, gain a more fine-scale and greater understanding of the specimens they find, rear, photograph, database and deliver. The parataxonomists also need to adjust to collecting more specimens of what appear to be the “same species” – cryptic species that cannot be distinguished by eye or even food plant alone – while having to work with the name changes and taxonomic uncertainty that comes with discovering that what looked like one species may be many.

Conclusions/Significance

These career parataxonomists, despite their lack of formal higher education, have proven very capable of absorbing and working around the additional complexity and requirements for accuracy and detail that are generated by adding barcoding to the field base of the ACG inventory. In the process, they have also gained a greater understanding of the fine details of phylogeny, relatedness, evolution, and species-packing in their own tropical complex ecosytems. There is no reason to view DNA barcoding as incompatible in any way with tropical biodiversity inventory as conducted by parataxonomists. Their year-round on-site inventory effort lends itself well to the sampling patterns and sample sizes needed to build a thorough barcode library. Furthermore, the biological understanding that comes with barcoding increases the scientific penetrance of biodiversity information, DNA understanding, evolution, and ecology into the communities in which the parataxonomists and their families are resident.

DNA barcoding the geometrid fauna of Bavaria (Lepidoptera): successes, surprises, and questions

BACKGROUND

The State of Bavaria is involved in a research program that will lead to the construction of a DNA barcode library for all animal species within its territorial boundaries. The present study provides a comprehensive DNA barcode library for the Geometridae, one of the most diverse of insect families.

METHODOLOGY/PRINCIPAL FINDINGS

This study reports DNA barcodes for 400 Bavarian geometrid species, 98 per cent of the known fauna, and approximately one per cent of all Bavarian animal species. Although 98.5% of these species possess diagnostic barcode sequences in Bavaria, records from neighbouring countries suggest that species-level resolution may be compromised in up to 3.5% of cases. All taxa which apparently share barcodes are discussed in detail. One case of modest divergence (1.4%) revealed a species overlooked by the current taxonomic system: Eupithecia goossensiata Mabille, 1869 stat.n. is raised from synonymy with Eupithecia absinthiata (Clerck, 1759) to species rank. Deep intraspecific sequence divergences (>2%) were detected in 20 traditionally recognized species.

CONCLUSIONS/SIGNIFICANCE

The study emphasizes the effectiveness of DNA barcoding as a tool for monitoring biodiversity. Open access is provided to a data set that includes records for 1,395 geometrid specimens (331 species) from Bavaria, with 69 additional species from neighbouring regions. Taxa with deep intraspecific sequence divergences are undergoing more detailed analysis to ascertain if they represent cases of cryptic diversity.

Edible Lepidoptera in Mexico: Geographic distribution, ethnicity, economic and nutritional importance for rural people

In this paper, we reported the butterflies and moths that are consumed in Mexico. We identified 67 species of Lepidoptera that are eaten principally in their larval stage in 17 states of Mexico. These species belong to 16 families: Arctiidae, Bombycidae, Castniidae, Cossidae, Geometridae, Hepialidae, Hesperiidae, Lasiocampidae, Noctuidae, Nymphalidae, Papilionidae, Pieridae, Pyralidae, Saturniidae, Sesiidae, and Sphingidae.Saturniidae, Pieridae, Noctuidae and Nymphalidae were the more species consumed with 16, 11, 9, and 8 species, respectively. The genera with the largest numbers of species were: Phassus, Phoebis, Hylesia and Spodoptera, with three species.Their local distribution, corresponding to each state of Mexico, is also presented.

From the phylogeny of the Satyrinae butterflies to the systematics of Euptychiina (lepidoptera: nymphalidae): history, progress and prospects

We review the various proposals of evolutionary and classification schemes for Satyrinae and particularly Euptychiina butterflies, assessing progress and prospects of research for the group. Among the highlights is the proposal to include Morphini, Brassolini and Amathusiini as part of Satyrinae. Although it is clear that this hypothesis requires further investigation, phylogenetic studies recently conducted recover this clade as part of Satyrinae with high support. The phylogenetic analyses for Euptychiina carried out to date recover the monophyly of the group and have identified a variety of genera as non-monophyletic. Further work is necessary to resolve the position of the subtribe and the evolutionary relationships of several genera.

A new species of alucita L. (Lepidoptera: alucitidae) from northern Chile

Male and female adults of a new species of Alucita L. (Lepidoptera: Alucitidae) are described and illustrated from the Azapa Valley, northern Chile. Immature stages are associated with fruit of "chuve", Tecoma fulva (Cav.) D. Don. (Bignoniaceae). This is the first species of Alucitidae described from Chile.

Evaluating resistance to Bt toxin Cry1Ab by F2 screen in European populations of Ostrinia nubilalis (Lepidoptera: Crambidae)

The large-scale cultivation of transgenic crops producing Bacillus thuringiensis (Bt) toxins have already lead to the evolution of Bt resistance in some pest populations targeted by these crops. We used the F2 screening method for further estimating the frequency of resistance alleles of the European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), to Bt maize, Zea mays L., producing the Cry1Ab toxin. In France, Germany, and Italy, 784, 455, and 80 lines of European corn borer were screened for resistance to Mon810 maize, respectively. In Slovakia, 26 lines were screened for resistance to the Cry1Ab toxin. The cost of F2 screen performed in the four countries varied from U.S. dollars 300 to dollars 1300 per line screened. The major difference in cost was mostly due to a severe loss of univoltine lines during the screen in Germany and Slovakia. In none of the screened lines did we detect alleles conferring resistance to Mon810 maize or to the Cry1Ab toxin. The frequency of resistance alleles were < 1.0 x 10(-3), < 1.6 x 10(-3), < 9.2 x 10(-3), and < 2.6 x 10(-2) in France, Germany, Italy, and Slovakia, with 95% probability, respectively. The average detection probability over all lines was approximately 90%. Making the assumption that European corn borer populations in these countries belong to the same genetic entity, the frequency of alleles conferring resistance to the Cry1Ab produced by the Mon810 maize in western and central Europe was 1.0 x 10(-4), with a 95% confidence interval of 0-3.0 x 10(-4).

Comprehensive gene and taxon coverage elucidates radiation patterns in moths and butterflies

Lepidoptera (butterflies and moths) represent one of the most diverse animals groups. Yet, the phylogeny of advanced ditrysian Lepidoptera, accounting for about 99 per cent of lepidopteran species, has remained largely unresolved. We report a rigorous and comprehensive analysis of lepidopteran affinities. We performed phylogenetic analyses of 350 taxa representing nearly 90 per cent of lepidopteran families. We found Ditrysia to be a monophyletic taxon with the clade Tischerioidea + Palaephatoidea being the sister group of it. No support for the monophyly of the proposed major internested ditrysian clades, Apoditrysia, Obtectomera and Macrolepidoptera, was found as currently defined, but each of these is supported with some modification. The monophyly or near-monophyly of most previously identified lepidopteran superfamilies is reinforced, but several species-rich superfamilies were found to be para- or polyphyletic. Butterflies were found to be more closely related to 'microlepidopteran' groups of moths rather than the clade Macrolepidoptera, where they have traditionally been placed. There is support for the monophyly of Macrolepidoptera when butterflies and Calliduloidea are excluded. The data suggest that the generally short diverging nodes between major groupings in basal non-tineoid Ditrysia are owing to their rapid radiation, presumably in correlation with the radiation of flowering plants.

A mathematical model of exposure of non-target Lepidoptera to Bt-maize pollen expressing Cry1Ab within Europe

Genetically modified (GM) maize MON810 expresses a Cry1Ab insecticidal protein, derived from Bacillus thuringiensis (Bt), toxic to lepidopteran target pests such as Ostrinia nubilalis. An environmental risk to non-target Lepidoptera from this GM crop is exposure to harmful amounts of Bt-containing pollen deposited on host plants in or near MON810 fields. An 11-parameter mathematical model analysed exposure of larvae of three non-target species: the butterflies Inachis io (L.), Vanessa atalanta (L.) and moth Plutella xylostella (L.), in 11 representative maize cultivation regions in four European countries. A mortality-dose relationship was integrated with a dose-distance relationship to estimate mortality both within the maize MON810 crop and within the field margin at varying distances from the crop edge. Mortality estimates were adjusted to allow for physical effects; the lack of temporal coincidence between the susceptible larval stage concerned and the period over which maize MON810 pollen is shed; and seven further parameters concerned with maize agronomy and host-plant ecology. Sublethal effects were estimated and allowance made for aggregated pollen deposition. Estimated environmental impact was low: in all regions, the calculated mortality rate for worst-case scenarios was less than one individual in every 1572 for the butterflies and one in 392 for the moth.

Assessing the value of DNA barcodes and other priority gene regions for molecular phylogenetics of Lepidoptera

BACKGROUND

Despite apparently abundant amounts of observable variation and species diversity, the order Lepidoptera exhibits a morphological homogeneity that has provided only a limited number of taxonomic characters and led to widespread use of nucleotides for inferring relationships. This study aims to characterize and develop methods to quantify the value of priority gene regions designated for Lepidoptera molecular systematics. In particular, I assess how the DNA barcode segment of the mitochondrial COI gene performs across a broad temporal range given its number one position of priority, most sequenced status, and the conflicting opinions on its phylogenetic performance.

METHODOLOGY/PRINCIPAL FINDINGS

Gene regions commonly sequenced for lepidoptera phylogenetics were scored using multiple measures across three categories: practicality, which includes universality of primers and sequence quality; phylogenetic utility; and phylogenetic signal. I found that alternative measures within a category often appeared correlated, but high scores in one category did not necessarily translate into high scores in another. The DNA barcode was easier to sequence than other genes, and had high scores for utility but low signal above the genus level.

CONCLUSIONS/SIGNIFICANCE

Given limited financial resources and time constraints, careful selection of gene regions for molecular phylogenetics is crucial to avoid wasted effort producing partially informative data. This study introduces an approach to assessing the value of gene regions prior to the initiation of new studies and presents empirical results to help guide future selections.

A new species of Moneuptychia Forster (Lepidoptera: Satyrinae: Euptychiina) from central Brazil

This paper describes a new species of Moneuptychia Forster from the cerrado in the Federal District and Goiás region in central Brazil, and from highland open vegetation (campos de altitude) of Minas Gerais and Paraná. We provide details of the adult morphology and discuss the new species placement in the genus Moneuptychia.

A new species of the genus Parasa Moore (Lepidoptera: Limacodidae) from Yemen

A new species Parasa dusii Solovyev and Saldaitis from northern Yemen is described (holotype in Museum Witt, Munich; Germany). The species has tendency to lose the green pigment typical for other congeners. It is provisionally placed into the genus Parasa Moore, 1859 where it is closely related to P. divisa West, 1940, P. catori Bethune-Baker, 1911, P. marginata West, 1940, P. thamia Rungs, 1951, P. dentina Hering, 1932, P. ananii Karsch, 1896, and P. semiochracea Hering, 1933. The relationship of the new species to these African species suggests its secondary penetration into the Arabian Peninsula from an origin in tropical Africa. The problems of monophyly of the genus Parasa and several associated genera are briefly discussed. All important characters of the new species, and some related species, are illustrated.

Toward reconstructing the evolution of advanced moths and butterflies (Lepidoptera: Ditrysia): an initial molecular study

BACKGROUND

In the mega-diverse insect order Lepidoptera (butterflies and moths; 165,000 described species), deeper relationships are little understood within the clade Ditrysia, to which 98% of the species belong. To begin addressing this problem, we tested the ability of five protein-coding nuclear genes (6.7 kb total), and character subsets therein, to resolve relationships among 123 species representing 27 (of 33) superfamilies and 55 (of 100) families of Ditrysia under maximum likelihood analysis.

RESULTS

Our trees show broad concordance with previous morphological hypotheses of ditrysian phylogeny, although most relationships among superfamilies are weakly supported. There are also notable surprises, such as a consistently closer relationship of Pyraloidea than of butterflies to most Macrolepidoptera. Monophyly is significantly rejected by one or more character sets for the putative clades Macrolepidoptera as currently defined (P < 0.05) and Macrolepidoptera excluding Noctuoidea and Bombycoidea sensu lato (P < or = 0.005), and nearly so for the superfamily Drepanoidea as currently defined (P < 0.08). Superfamilies are typically recovered or nearly so, but usually without strong support. Relationships within superfamilies and families, however, are often robustly resolved. We provide some of the first strong molecular evidence on deeper splits within Pyraloidea, Tortricoidea, Geometroidea, Noctuoidea and others.Separate analyses of mostly synonymous versus non-synonymous character sets revealed notable differences (though not strong conflict), including a marked influence of compositional heterogeneity on apparent signal in the third codon position (nt3). As available model partitioning methods cannot correct for this variation, we assessed overall phylogeny resolution through separate examination of trees from each character set. Exploration of "tree space" with GARLI, using grid computing, showed that hundreds of searches are typically needed to find the best-feasible phylogeny estimate for these data.

CONCLUSION

Our results (a) corroborate the broad outlines of the current working phylogenetic hypothesis for Ditrysia, (b) demonstrate that some prominent features of that hypothesis, including the position of the butterflies, need revision, and (c) resolve the majority of family and subfamily relationships within superfamilies as thus far sampled. Much further gene and taxon sampling will be needed, however, to strongly resolve individual deeper nodes.

Cathepsin L-like cysteine proteinase (DcCathL) from Delia coarctata (wheat bulb fly): basis of insecticidal activity

A cDNA encoding a cathepsin L-like cysteine proteinase (DcCathL) was prepared from gut tissue of larvae of wheat bulb fly (Delia coarctata: Diptera). The predicted protein is a homologue of the product of Drosophila melanogaster gene Cp-1 (CG6692), and is similar to a sub-family of cysteine proteinases found in other insects which have roles in tissue remodelling during development, and moulting. Recombinant DcCathL was produced using the yeast Pichia pastoris as expression host, and showed hydrolytic activity in vitro towards the synthetic substrate Z-Phe-Arg-AMC with a pH optimum of 4.5. DcCathL was insecticidal to lepidopteran larvae when injected into haemolymph, causing mortality that was accompanied by systemic melanisation, suggesting that DcCathL was affecting the immune-related proteolytic activation cascade leading to production of active phenoloxidase. This process is normally negatively regulated by serpins in the haemolymph. Recombinant serpins from cabbage moth (Mamestra brassicae) did not inhibit DcCathL, and were susceptible to degradation by the enzyme in vitro in buffer and extracted haemolymph. When M. brassicae larvae were co-injected with a lethal dose of DcCathL and exogenous recombinant serpins, no mortality or systemic melanisation was observed, suggesting that the insecticidal effects of DcCathL in vivo result from degradation of endogenous serpins.

Barcoding lepidoptera: current situation and perspectives on the usefulness of a contentious technique

Faced by a growing need of identification and delimitation of new and established cryptic species that are being lost at an increasing rate, taxonomists can now more than ever take advantage of an enormous variety of new molecular and computational tools. At this moment they should be open to all new available technologies in the so called 'technology-driven revolution' in systematics. The use of the 'DNA barcode' has been discussed by those applying successfully this approach to identify and diagnose species and by those who believe that the flaws in the use of this molecular marker are as many as to negate the worth of its employment. For insects of the order Lepidoptera neither side seems totally correct or wrong, and although many groups of lepidopterans have been taxonomically resolved by using exclusively or additionally this marker for diagnoses, for others the 'barcode' helped little to resolve taxonomic issues. Here we briefly present some pros and cons of using DNA barcode as a tool in taxonomic studies, with special attention to studies with groups of Lepidoptera developed in the last few years.

A new species of Eretris Thieme (Lepidoptera: Nymphalidae, Satyrinae) from the Elbow of the Andes region in Bolivia

A new species of cloud forest butterfly, Eretris julieta n. sp. is described from a region of south-central Bolivia known as the Elbow of the Andes. It is the southernmost known representative of the genus, hitherto known only from a restricted area of interandean valleys in the department of Santa Cruz. Its affinities with other congeners are evaluated.

Phylogeography and genetic diversity of a widespread Old World butterfly, Lampides boeticus (Lepidoptera: Lycaenidae)

BACKGROUND

Evolutionary genetics provides a rich theoretical framework for empirical studies of phylogeography. Investigations of intraspecific genetic variation can uncover new putative species while allowing inference into the evolutionary origin and history of extant populations. With a distribution on four continents ranging throughout most of the Old World, Lampides boeticus (Lepidoptera: Lycaenidae) is one of the most widely distributed species of butterfly. It is placed in a monotypic genus with no commonly accepted subspecies. Here, we investigate the demographic history and taxonomic status of this widespread species, and screen for the presence or absence of the bacterial endosymbiont Wolbachia.

RESULTS

We performed phylogenetic, population genetic, and phylogeographic analyses using 1799 bp of mitochondrial sequence data from 57 specimens collected throughout the species' range. Most of the samples (>90%) were nearly genetically identical, with uncorrected pairwise sequence differences of 0-0.5% across geographic distances >9,000 km. However, five samples from central Thailand, Madagascar, northern Australia and the Moluccas formed two divergent clades differing from the majority of samples by uncorrected pairwise distances ranging from 1.79-2.21%. Phylogenetic analyses suggest that L. boeticus is almost certainly monophyletic, with all sampled genes coalescing well after the divergence from three closely related taxa included for outgroup comparisons. Analyses of molecular diversity indicate that most L. boeticus individuals in extant populations are descended from one or two relatively recent population bottlenecks.

CONCLUSION

The combined analyses suggest a scenario in which the most recent common ancestor of L. boeticus and its sister taxon lived in the African region approximately 7 Mya; extant lineages of L. boeticus began spreading throughout the Old World at least 1.5 Mya. More recently, expansion after population bottlenecks approximately 1.4 Mya seem to have displaced most of the ancestral polymorphism throughout its range, though at least two early-branching lineages still persist. One of these lineages, in northern Australia and the Moluccas, may have experienced accelerated differentiation due to infection with the bacterial endosymbiont Wolbachia, which affects reproduction. Examination of a haplotype network suggests that Australia has been colonized by the species several times. While there is little evidence for the existence of morphologically cryptic species, these results suggest a complex history affected by repeated dispersal events.

Lepidoptera and associated parasitoids attacking Hass and non-Hass avocados in Guatemala

A 5-mo survey for fruit feeding Lepidoptera attacking Hass and non-Hass avocados (Persea americana Miller [Lauraceae]) was conducted in Guatemala from 1 November 2006 to 1 April 2007. In total, 6,740 fruit were collected from 22 different areas in Guatemala. Eight species of Lepidoptera, of which at least two are species new to science, were reared from avocado fruit. Reared Lepidoptera were Amorbia santamaria Phillips and Powell, Cryptaspasma sp. nr. lugubris, Euxoa sorella Schaus, Histura n. sp., Holcocera n. sp., Micrathetis triplex Walker, Netechma pyrrhodelta (Meyrick), and Stenoma catenifer Walsingham. Hymenopteran parasitoids were reared from larvae of C. sp. nr. lugubris and S. catenifer. One species of parasitoid, Pseudophanerotoma sp., was reared from field collected C. sp. nr. lugubris larvae. The dominant parasitoid reared from S. catenifer was a gregarious Apanteles sp. Other parasitoid species reared from S. catenifer larvae were Brachycyrtus sp., Macrocentrus sp., and Pristomerus sp. The oviposition preference of C. sp. nr. lugubris for avocado fruit hanging in trees, dropped fruit on the ground, or exposed avocado seeds was investigated by studying the oviposition preferences of adult female moths and determining egg hatch times in the laboratory, and by investigating the longevity of avocado fruit on the ground under prevailing field conditions. Together, data from these studies suggested that C. sp. nr. lugubris may be an unrecognized pest of avocados that causes hanging fruit to drop to the ground prematurely. The influence of season and altitude on the phenology and distribution of avocado feeding Lepidoptera in Guatemala is discussed.

Diversity of aminopeptidases, derived from four lepidopteran gene duplications, and polycalins expressed in the midgut of Helicoverpa armigera: identification of proteins binding the delta-endotoxin, Cry1Ac of Bacillus thuringiensis

Helicoverpa armigera midgut proteins that bind the Bacillus thuringiensis (Bt) delta-endotoxin Cry1Ac were purified by affinity chromatography. SDS-PAGE showed that several proteins were eluted with N-acetylgalactosamine and no further proteins were detected after elution with urea. Tandem mass spectral data for tryptic peptides initially indicated that the proteins resembled aminopeptidases (APNs) from other lepidopterans and cDNA sequences for seven APNs were isolated from H. armigera through a combination of cloning with primers derived from predicted peptide sequences and established EST libraries. Phylogenetic analysis showed lepidopteran APN genes in nine clades of which five were part of a lepidopteran-specific radiation. The Cry1Ac-binding proteins were then identified with four of the seven HaAPN genes. Three of those four APNs are likely orthologs of APNs characterised as Cry1Ac-binding proteins in other lepidopterans. The fourth Cry1Ac-binding APN has orthologs not previously identified as Cry1Ac-binding partners. The HaAPN genes were expressed predominantly in the midgut through larval development. Each showed consistent expression along the length of the midgut but five of the genes were expressed at levels about two orders of magnitude greater than the remaining two. The remaining mass spectral data identified sequences encoding polycalin proteins with multiple lipocalin-like domains. A polycalin has only been previously reported in another lepidopteran, Bombyx mori, but polycalins in both species are now linked with binding of Bt Cry toxins. This is the first report of hybrid, lipocalin-like domains in shorter polycalin sequences that are not present in the longest sequence. We propose that these hybrid domains are generated by alternative splicing of the mRNA.

Evolutionary patterns in chromosome numbers in neotropical Lepidoptera. I. Chromosomes of the Heliconiini (family Nymphalidae: subfamily Nymphalinae)

Chromosome counts in meiotic metaphase plates in the gonads of 67 of the probable 68 species of mimetic neotropical heliconian butterflies (Nymphalidae), representing 1524 individuals in 617 subspecies and geographically separate populations from southern Texas to northern Argentina, revealed a consistent haploid number of n = 21 in the genus Heliconius (except for the most advanced species with n = 33, 37, 56, and 60) and n = 31 in the more primitive genera (Eueides, Dryas, Dryadula, Agraulis, and Dione), with a transitional genus (Neruda) showing three species with n = 28-32, 21-22 + 5-10 "microchromosomes", and 20-22 + 1-5 "microchromosomes". The genus Laparus, with a single polymorphic species doris, probably an offshoot of early Heliconius, shows wide karyotypic variation (n = 20-30, 38) sometimes even within a single individual. The two most primitive genera also show much variation: Podotricha has two species with n = 9 and n = 26-29; and Philaethria shows many phenotypically similar species, two with n = 29 and a still uncertain number (at least 3) with n = 88 (most common), 67-72 (most widespread), 62 (very restricted geographically), 52, 21, and 12. Several interspecific hybrids (Heliconius cydno x H. melpomene) showed normal chromosome pairing, while deficient pairing was seen in intersubspecific hybrids in Eueides tales and Heliconius sara. The importance of these results in the evolutionary study of polytypic tropical species is discussed.

[Cloning and analysis of adenine nucleotide translocase gene in Helicoverpa armigera]

A cDNA clone encoding the ADP/ATP translocase in Helicoverpa armigera has been identified by RT-PCR, 5'and 3'RACE methods. Sequence analysis shows that it is 1,190 bp long and contains a single open reading frame (ORF, 133-1,033 bp) encoding a protein of 300 amino acids (GenBank submission number, AY253868). The protein has a 22 aa signal peptide on its N-terminal, which leads the protein locating onto the inner membrane of the mitochondria. It also has three conserved domains of the mitochondrial carrier protein forming a channel to exchange ATP and ADP energy molecule through the inner membrane of the mitochondria. It shows extensive similarities to the known ADP/ATP translocase poly-peptides. The ADP/ATP translocase similarity was up to 90% in the Lepidoptera.

The signal environment is more important than diet or chemical specialization in the evolution of warning coloration

Aposematic coloration, or warning coloration, is a visual signal that acts to minimize contact between predator and unprofitable prey. The conditions favoring the evolution of aposematic coloration remain largely unidentified. Recent work suggests that diet specialization and resultant toxicity may play a role in facilitating the evolution and persistence of warning coloration. Using a phylogenetic approach, we investigated the evolution of larval warning coloration in the genus Papilio (Lepidoptera: Papilionidae). Our results indicate that there are at least four independent origins of aposematic larval coloration within Papilio. Controlling for phylogenetic relatedness among Papilio taxa, we found no evidence supporting the hypothesis that either diet specialization or chemical specialization facilitated the origin of aposematic larvae. However, there was a significant relationship between the signal environment and the evolution of aposematic larvae. Specifically, Papilio lineages feeding on herbaceous or narrow-leaved plants, regardless of the plants' taxonomic affiliation, were more likely to evolve aposematic larvae than were lineages feeding only on trees/shrubs or broad-leaved plants. These results demonstrate that factors other than diet specialization, such as the signal environment of predator-prey interactions, may play a large role in the initial evolution and persistence of aposematic coloration.