Euphorbia cyparissias

Research

The interdisciplinary approach in studying the evolution of the genus Hyles in the working group of Anna K. Hundsdoerfer includes data from numerous sources: morphology, molecular DNA-sequences, microsatellite genotyping, chemical ecology, breeding experiments, proteomics, transcriptomics (RNA) and genomics. The research aims at enlightening systematic-taxonomic, phylogenetic and population genetic questions, and as far as possible their functional background. It represents part of the Senckenberg research fields Biodiversity and Systematics and Biodiversity and Climate.
 

The hawkmoth genus Hyles (Lepidoptera: Sphingidae) is remarkably uniform in adult morphology and very variable in intra-specific larval characters, especially within the circum-Mediterranean Hyles euphorbiae. Analyses of the evolution of these organisms constitute the core of my research.

 

Phylogeny

Information from DNA sequences of mitochondrial and nuclear genes are used to analyse the phylogeny of Hyles (Hundsdoerfer et al., 2005a, 2009, 2017). The sequence data revealed the genus Hyles to have separated from its sister group in the Neotropics during the Oligocene/Eocene period.

Phylogeography & Integrative Taxonomy

Much research focusses on the evolution of the spurge hawkmoth species Hyles euphorbiae. Initially, a hypothesis was put forward for the five species formerly constituting the Hyles euphorbiae – complex (HEC): a clear geographical pattern of genetic differentiation into two main lineages, the European H. euphorbiae and the North African H. tithymali (Hundsdoerfer et al., 2005a, b). In the course of the years numerous mitochondrial lineages were found (Hundsdoerfer et al., 2011a, b, Mende et al., 2016) that only partly correspond to the distribution of larval pattern elementsand species definitions based mainly on morphological characters of the adults.

Two of the mitochondrial lineages occur only in sympatry with other lineages, i.e. do not have a distinct distribution area. These could be lineages that lost their discreteness by introgression and hybridisation. Analyses of museum specimens revealed that the northern border for the distribution of the ‘italica‘ lineage fluctuates in correlation with mean summer temperatures: in warm summers of the 1900s, 1940s and 2000s it reached more northern localities where it could not be found in the colder periods around the 1920s and 1970s (Mende et al., 2013).

Whereas microsatellite analyses (Hundsdoerfer et al., 2010a; Mende et al., 2011, 2016) corroborated two hybridising entities, whole genome ddRAD-Seq data revealed no monophyletic subunits within the entire former HEC, which is why the former species H. tithymali, H. sammuti, H. cretica and H. robertsi (including their subspecies) are synonymised with H. euphorbiae (Hundsdoerfer, Lee et al., 2019).

Running project: Mitochondrial data reveal at least three new Hyles (Lepidoptera) lineages (~15 currently valid species) in the Central Palaearctic (unpublished). However, hybridisation is frequent in this genus, thus comparative nuclear genomic data from historic DNA in museum exemplars aims to determine how many genomes mix to produce only seven wing patterns with intermediates, yet more than 40 larval polymorphisms, and to clarify the enigmatic taxonomy. This project “Hybrid species recognition using ‘Next Generation Sequencing’ (NGS) of museum specimens” is in the DFG-funded (SPP-1991) priority program Taxon-OMICS

 

Frost tolerance

Overwintering diapause pupae of Hyles euphorbiae are exposed to extremely different temperature regimes across their large distribution area, ranging from mild average 11°C during winter in the Mediterranean climate to an average of -23°C or below in Siberia.

In order to understand to which extent processes such as phenotypic plasticity of freeze protection mechanisms or local adaptation to freezing winter temperatures may explain the current geographic distribution of the species, we are interested in molecular mechanisms underlying cold response (Stuckas et al., 2014). Some candidate cold hardiness genes have been found in the transcriptome of Hyles euphorbiae (Barth, Buchwalder et al., 2018) that require further study.

Chemical Ecology

The larvae of Hyles euphorbiae are very conspicuous with their bright colouration. They rely on Euphorbia foodplants, which contain skin irritant, tumour-promoting and also toxic phorbol esters. However, chemical-ecological experiments report evidence that they appear to warn predators of their toxic gut contents only – i.e. contra common belief, they do not sequester phorbol esters from their food plant, but rather excrete them (Hundsdoerfer et al., 2005c).

An array of experiments were run to test as many species of Hyles for their sensibility towards the acute toxicity of Euphorbia phorbol esters. The hypothesis is that the insensibility to the toxicity of the spurge poison represents a key character in the adaptive radiation of the genus (Hundsdoerfer et al., 2019).

Some candidate detoxification genes have been found in the transcriptome of Hyles euphorbiae (Barth, Buchwalder et al., 2018) that require further study. Enzyme candidates will be characterized and TPA metabolites of H. euphorbiae will be compared to those of additional Hyles species with different food plant spectra and TPA sensitivity. This DFG funded project “Spurge toxins as a winder of evolution in hawkmoths: Phorbol ester detoxification by Hyles euphorbiae (Lepidoptera: Sphingidae)” started end of 2019.

 

Funding

Third party funding by the DFG

2006-2013 “Phylogeny and Chemical Ecology…” HU1561/1-1, 1-2.

2018-2021 “Hybrid species…” in the TaxonOMICS DFG SPP 1991 HU1561/5-1.

2019-2022 “Spurge toxins… HU1561/7-1

 

References

(chronologically)

Hundsdoerfer, A. K., Lee, K. M., Kitching, I. J., & Mutanen, M. (2019) Genome-wide SNP data reveal an overestimation of species diversity in a group of hawkmoths. Genome biology and evolution., 2136-2150. PDF

Hundsdoerfer, A. K., Buchwalder, K., O’Neill, M. A., & Dobler, S. (2019) Chemical ecology traits in an adaptive radiation: TPA-sensitivity and detoxification in Hyles and Hippotion (Sphingidae, Lepidoptera) larvae. Chemoecology, 1-13. PDF

Barth, M. B., Buchwalder, K., Kawahara, A. Y., Zhou, X., Liu, S., Krezdorn, N., Rotter, B., Horres, R. & Hundsdoerfer, A. K. (2018). Functional characterization of the Hyles euphorbiae hawkmoth transcriptome reveals strong expression of phorbol ester detoxification and seasonal cold hardiness genes. Frontiers in Zoology, 15(1), 20. PDF

Hundsdoerfer, A. K., Päckert, M., Kehlmaier, C., Strutzenberger, P., & Kitching, I. J. (2017) Museum archives revisited: Central Asiatic hawkmoths reveal exceptionally high late Pliocene species diversification (Lepidoptera, Sphingidae). Zoologica Scripta 46(5), 552-570. PDF

Mende, M. B., Bartel, M. & Hundsdoerfer, A. K. (2016) A comprehensive phylogeography of the Hyles euphorbiae complex (Lepidoptera: Sphingidae) indicates a ‘glacial refuge belt’. Scientific Reports, 6. PDF

Stuckas, H., Mende, M. & Hundsdoerfer, A.K. (2014) Response to cold acclimation in diapause pupae of Hyles euphorbiae (Lepidoptera, Sphingidae): candidate biomarker identification using proteomics. Insect Molecular Biology 23, 444-456. PDF

Mende, M.B. & Hundsdoerfer, A.K. (2013) Mitochondrial lineage sorting in action — historical biogeography of the Hyles euphorbiae complex (Sphingidae, Lepidoptera) in Italy. BMC Evolutionary Biology 13, 83. PDF

Hundsdoerfer, A.K., Mende, M.B., Kitching, I.J. & Cordellier, M. (2011a) Taxonomy, phylogeography and climate relations of the Western Palaearctic spurge hawkmoth (Lepidoptera, Sphingidae, Macroglossinae). Zoologica Scripta 40, 403-417. PDF

Hundsdoerfer, A.K., Mende, M.B., Harbich, H., Pittaway, A.R., & Kitching, I.J. (2011b) Larval pattern morphotypes in the Western Palaearctic Hyles euphorbiae complex (Lepidoptera: Sphingidae, Macroglossinae). Insect Systematics & Evolution 42, 41-86.

Mende, M.B., Stuckas, H. & Hundsdoerfer, A.K. (2011) Eight new microsatellite loci of the Western Palearctic Hyles euphorbiae complex (Lepidoptera, Sphingidae). Annales Zoologici Fennici 48, 142-146.

Hundsdoerfer, A.K., Sanetra, M., Corbeil, D. & Stuckas, H. (2010) Eleven hawkmoth microsatellite loci of Canary Island Hyles tithymali (Lepidoptera). Conservation Genetics Resources 2, 241–244.

Hundsdoerfer, A.K. & Kitching, I.J. (2010) A method for improving DNA yield from century-plus old specimens of large Lepidoptera while minimizing damage to external and internal abdominal characters. Arthropod Systematics & Phylogeny 68(1), 151-155. PDF

Hundsdoerfer, A.K., Rubinoff, D., Attié, M., Wink, M. & Kitching, I.J. (2009) A revised molecular phylogeny of the globally distributed hawkmoth genus Hyles (Lepidoptera: Sphingidae), based on mitochondrial and nuclear DNA sequences. Molecular Phylogenetics and Evolution 52, 852-865.

Hundsdoerfer, A.K., Kitching, I. J. & Wink, M. (2005a) A molecular phylogeny of the hawkmoth genus Hyles (Lepidoptera: Sphingidae, Macroglossinae). Molecular Phylogenetics and Evolution 35, 442-458.

Hundsdoerfer, A.K., Kitching, I. J. & Wink, M. (2005b) The phylogeny of the Hyleseuphorbiae-complex (Lepidoptera: Sphingidae): molecular evidence from sequence data and ISSR-PCR fingerprints. Organisms, Diversity & Evolution 5, 173-198.

Hundsdoerfer, A.K., Tshibangu, J.N., Wetterauer, B. & Wink, M. (2005c) Sequestration of phorbol esters by aposematic larvae of Hyles euphorbiae? Chemoecology 15, 261-267.