Research Article |
Corresponding author: Paola D’Alessandro ( paola.dalessandro@univaq.it ) Academic editor: Caroline Chaboo
© 2019 Daniele Salvi, Paola D’Alessandro, Maurizio Biondi.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Salvi D, D’Alessandro P, Biondi M (2019) Host plant associations in Western Palaearctic Longitarsus flea beetles (Chrysomelidae, Galerucinae, Alticini): a preliminary phylogenetic assessment. In: Schmitt M, Chaboo CS, Biondi M (Eds) Research on Chrysomelidae 8. ZooKeys 856: 101-114. https://doi.org/10.3897/zookeys.856.32430
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Longitarsus Latreille (Chrysomelidae, Galerucinae, Alticini) is a very large genus of phytophagous insects, with more than 700 species distributed in all zoogeographical regions. Patterns of host use have been a central topic in phytophagous insect research. In this study a first assessment is provided to test the hypothesis that host-plant association is phylogenetically conserved in Western Palaearctic Longitarsus species. Maximum Likelihood and Bayesian Inference methods were used to infer a phylogeny based on DNA sequence data from two mitochondrial genes from 52 Longitarsus species from the Western Palaearctic. In agreement with the host phylogenetic conservatism hypothesis, a strict association between most of the recovered clades and specific plant families was found, except for species associated with Boraginaceae. Low phylogenetic resolution at deep nodes limited the evaluation of whether closely related Longitarsus clades are associated with the same plant family or to closely related plant families.
Longitarsus, molecular phylogeny, Palaearctic region, phylogenetic conservatism in host use, phytophagous insects
Longitarsus Latreille, 1829 is a mega-diverse genus of phytophagous insects and the most speciose among flea beetles (Chrysomelidae, Galerucinae, Alticini) with more than 700 known species. It is widespread through all zoogeographical regions (
Relationships among Chrysomelidae and their host plants has been investigated from a biochemical, behavioural, and phylogenetic point of view, and at various taxonomic levels, often with the aim of understanding the biology of actual or potential pests (
In this paper, we conduct a molecular phylogenetic analysis on 52 Western Palaearctic Longitarsus species to map host plant data in order to assess whether the pattern observed is consistent with the phylogenetic conservatism hypothesis. If it is consistent, we would expect to find a) closely related Longitarsus species (single clades) to be associated with a specific plant family; b) Longitarsus clades associated with a specific plant family to form a single lineage.
We analysed 52 Longitarsus species (Table
Information on host plants, collection, and GenBank accession numbers for the 52 species of Longitarsus and Batophila aerata (outgroup) used in this study.
Species | Host plant family | Trophic Range | Source for molecular analysis | Permits | Deposits | GenBank accession number | |
---|---|---|---|---|---|---|---|
cox1 | 16S | ||||||
Batophila aerata (Marsham) | Rosaceae | OLI | Italy, Abruzzo (AQ), Roio Piano, 42°20'00.85"N 13°20'06.28"E, 930 m a.s.l., 13.v.2017, adult on Rubus sp. (Rosaceae) [det. M. Biondi, voucher db37] | not needed | Collection M. Biondi, University of L’Aquila (Italy) | requested | requested |
Longitarsus aeneicollis (Faldermann) | Asteraceae, Boraginaceae, Lamiaceae | POL | Italy, Abruzzo (TE), Prati di Tivo, 42°30'26.40"N 13°33'14.46"E; 1344 m a.s.l., 11.vii.2018, adult on Boraginaceae [det. M. Biondi, voucher db46] | Gran Sasso e Monti della Laga National Park. Prot. n. 0007403/18 | Collection M. Biondi, University of L’Aquila (Italy) | requested | requested |
Longitarsus aeneus Kutschera | Boraginaceae | OLI | Italy, Abruzzo (TE), Guazzano, 42°44'03.6"N 13°38'49.8"E, 563 m a.s.l., 24.iv.2017, adult on Borago officinalis (Boraginaceae) [det. M. Biondi, voucher db15] | not needed | Collection M. Biondi, University of L’Aquila (Italy) | KX943357 | requested |
Longitarsus anchusae (Paykull) | Boraginaceae | OLI | Italy, Abruzzo (AQ), Aprati, 42°32'10.9"N 13°27'14.9"E, 862 m a.s.l., 19.v.2017, adult on Anchusa italica (Boraginaceae) [det. M. Biondi, voucher db19] | Gran Sasso e Monti della Laga National Park. Prot. n. 0007804/17 | Collection M. Biondi, University of L’Aquila (Italy) | KM448991 | requested |
Longitarsus atricillus (Linnaeus) | Asteraceae, Ranunculaceae, Fabaceae, Scrophulariaceae | POL | GenBank | KX943363 | KP763161 | ||
Longitarsus ballotae (Marsham) | Lamiaceae | OLI | GenBank | KM446857 | KC186008 | ||
Longitarsus bedelii Uhagon | ? | ? | GenBank | – | KP763150 | ||
Longitarsus brisouti Heikertinger | Asteraceae | OLI | GenBank | KM439696 | – | ||
Longitarsus brunneus (Duftschmid) | Ranunculaceae | MON | GenBank | KM452511 | – | ||
Longitarsus celticus Leonardi | Lamiaceae | OLI | GenBank | KU908777 | – | ||
Longitarsus cerinthes (Schrank) | Boraginaceae | OLI | GenBank | KX943478 | KX943478 | ||
Longitarsus curtus (Allard) | Boraginaceae | OLI | GenBank | KX943501 | KX943501 | ||
Longitarsus dorsalis (Fabricius) | Asteraceae | MON | GenBank | KX943359 | KX943359 | ||
Longitarsus echii (Koch) | Boraginaceae | OLI | GenBank | KM439361 | – | ||
Longitarsus exsoletus (Linnaeus) | Boraginaceae | OLI | GenBank | KX943418 | KX943418 | ||
Longitarsus fallax Weise | Boraginaceae | OLI | Italy, Abruzzo (TE), Piancarani, 42°44'30.6"N 13°43'58.2"E, 191 m a.s.l., 24.iv.2017, adult on Borago officinalis (Boraginaceae) [det. M. Biondi, voucher db14] | not needed | Collection M. Biondi, University of L’Aquila (Italy) | requested | requested |
Longitarsus foudrasi Weise | Scrophulariaceae | OLI | Italy, Abruzzo (AQ), Casaline, 42°25'01.4"N 13°11'58.2"E, 1126 m a.s.l., 8.vii.2018, adult on Scrophularia sp. (Scrophulariaceae) [det. M. Biondi, voucher db43] | not needed | Collection M. Biondi, University of L’Aquila (Italy) | requested | requested |
Longitarsus helvolus Kutschera | Lamiaceae | OLI | GenBank | KU916133 | – | ||
Longitarsus holsaticus (Linnaeus) | Plantaginaceae | OLI | GenBank | KJ965710 | – | ||
Longitarsus isoplexidis Wollaston | Boraginaceae | MON | Portugal, Madeira Island, Encumeada, 32°44'24.2"N 17°02'55.0"W, 1316 m a.s.l., 1.iii.2017, adult on Echium candicans (Boraginaceae) [det. M. Biondi, voucher db7] | not needed | Collection M. Biondi, University of L’Aquila (Italy) | requested | requested |
Longitarsus languidus Kutschera | Asteraceae | MON | GenBank | KU906343 | – | ||
Longitarsus lateripunctatus (Rosenhauer) | Boraginaceae | OLI | Italy, Lazio (RM), Rome, 41°52'45.62"N 12°27'31.96"E, 50 m a.s.l., 7.v.2017, adult on Echium vulgare (Boraginaceae) [det. M. Biondi, voucher db16] | not needed | Collection M. Biondi, University of L’Aquila (Italy) | requested | requested |
Longitarsus lewisii (Baly) | Plantaginaceae | OLI | GenBank | KJ964861 | – | ||
Longitarsus lindbergi Madar & Madar | Asteraceae | OLI | Portugal, Madeira Island, Encumeada, 32°44'24.2"N 17°02'55.0"W, 1316 m a.s.l., 1.iii.2017, adult on Pericallis aurita (Asteraceae) [det. M. Biondi, voucher db23] | not needed | Collection M. Biondi, University of L’Aquila (Italy) | requested | requested |
Longitarsus linnaei (Duftschmid) | Boraginaceae | OLI | Italy, Abruzzo (AQ), Onna, 42°19'22"N 13°28'24"E; 650 m a.s.l., 14.iv.2017, adult on Symphytum tuberosum (Boraginaceae) [det. M. Biondi, voucher db12] | not needed | Collection M. Biondi, University of L’Aquila (Italy) | requested | requested |
Longitarsus lycopi (Foudras) | Lamiaceae | OLI | Italy, Abruzzo (TE), Prato Selva, 42°31'46.74"N 13°30'19.08"E, 1178 m a.s.l., 11.vii.2018, adult on Mentha sp. (Lamiaceae) [det. M. Biondi, voucher db50] | Gran Sasso e Monti della Laga National Park. Prot. n. 0007403/18 | Collection M. Biondi, University of L’Aquila (Italy) | KX943332 | requested |
Longitarsus melanocephalus (De Geer) | Plantaginaceae | MON | GenBank | KX943469 | KX943469 | ||
Longitarsus membranaceus (Foudras) | Lamiaceae | OLI | GenBank | KX943473 | KX943473 | ||
Longitarsus minusculus (Foudras) | Lamiaceae | OLI | GenBank | KM442213 | KP763142 | ||
Longitarsus nasturtii (Fabricius) | Boraginaceae | OLI | Italy, Lazio (RM), Rome, 41°54'50.58"N 12°22'57.12"E, 65 m a.s.l., 14.v.2017 [det. M. Biondi, voucher db34] | not needed | Collection M. Biondi, University of L’Aquila (Italy) | KM442304 | requested |
Longitarsus niger (Koch) | Plantaginaceae | OLI | GenBank | KX943504 | KX943504 | ||
Longitarsus nigrocillus (Motschulsky) | Convolvulaceae | OLI | GenBank | KX943464 | KX943464 | ||
Longitarsus nigrofasciatus (Goeze) | Scrophulariaceae | OLI | GenBank | KX943438 | KX943438 | ||
Longitarsus obliteratus (Rosenhauer) | Lamiaceae | OLI | Italy, Abruzzo (AQ), Roio Piano, 42°19'29.91"N 13°20'24.87"E, 1011 m a.s.l., 15.vii.2018, adult on Thymus sp. (Lamiaceae) [det. M. Biondi, voucher db57] | not needed | Collection M. Biondi, University of L’Aquila (Italy) | KM447410 | requested |
Longitarsus ochroleucus (Marsham) | Asteraceae | OLI | GenBank | KM448633 | KP763117 | ||
Longitarsus ordinatus (Foudras) | Lamiaceae | OLI | GenBank | KX943383 | KP763143 | ||
Longitarsus pellucidus (Foudras) | Convolvulaceae | OLI | GenBank | KR480207 | – | ||
Longitarsus pinguis Weise | Boraginaceae | OLI | Italy, Abruzzo (AQ), Campo Imperatore, 42°26'17.8"N 13°35'41.2"E, 1760 m a.s.l., 21.vi.2017, adult on Cynoglossum magellense (Boraginaceae) [det. M. Biondi, voucher db21] | Gran Sasso e Monti della Laga National Park. Prot. n. 0007804/17 | Collection M. Biondi, University of L’Aquila (Italy) | requested | requested |
Longitarsus plantagomarittimus Dollman | Plantaginaceae | MON | GenBank | – | EF421523 | ||
Longitarsus pratensis (Panzer) | Plantaginaceae | OLI | GenBank | KX943360 | KX943360 | ||
Longitarsus pulmonariae Weise | Boraginaceae | OLI | GenBank | KU907407 | – | ||
Longitarsus quadriguttatus Pontoppidan | Boraginaceae | OLI | GenBank | KM446524 | – | ||
Longitarsus rectilineatus (Foudras) | Lamiaceae | OLI | Italy, Lazio (RI), Val di Fua, 42°10'30"N 13°19'19"E; 1300–1500 m a.s.l.,13.ix.2017, adult on Daphne laureola (Thymelaeaceae; refuge plant) [det. M. Biondi, voucher db35] | Sirente Velino Natural Park Prot. n. 1441 22/06/2017 | Collection M. Biondi, University of L’Aquila (Italy) | requested | requested |
Longitarsus reichei (Allard) | Plantaginaceae | OLI | GenBank | KU907319 | – | ||
Longitarsus rutilus (Illiger) | Scrophulariaceae | MON | GenBank | KX943491 | KX943491 | ||
Longitarsus salviae Gruev | Lamiaceae | MON | Italy, Abruzzo (AQ), Ortolano, 42°29'51.3"N 13°23'12.5"E, 1133 m a.s.l., 27.vii.2017, adult on Thymus sp. (Lamiaceae) [det. M. Biondi, voucher db31] | Gran Sasso e Monti della Laga National Park. Prot. n. 0007804/17 | Collection M. Biondi, University of L’Aquila (Italy) | KU907298 | requested |
Longitarsus saulicus Gruev & Doeberl | Boraginaceae | OLI | Israel, Har Bracha, Amasa Spring, 32°11'35.93"N 35°15'54.21"E, 864 m a.s.l., 27.iii.2017, adult on Anchusa sp. (Boraginaceae) [det. M. Biondi, voucher db11] | not needed | Collection M. Biondi, University of L’Aquila (Italy) | requested | requested |
Longitarsus scutellaris (Mulsant & Rey) | Plantaginaceae | MON | GenBank | KR484199 | – | ||
Longitarsus springeri Leonardi | Asteraceae | MON | Italy, Abruzzo (AQ), Campo Imperatore, 42°26'55"N 13°32'24"E, 2140 m a.s.l., 23.viii.2018, adult on Senecio rupestris (Asteraceae) [det. M. Biondi, voucher db24] | Gran Sasso e Monti della Laga National Park. Prot. n. 0007403/18 | Collection M. Biondi, University of L’Aquila (Italy) | requested | requested |
Longitarsus succineus (Foudras) | Asteraceae | OLI | Italy, Abruzzo (AQ), Valico delle Capannelle, 42°27'33.96"N 13°21'7.56"E, 1312 m a.s.l., 15.v.2017 [det. M. Biondi, voucher db53] | Gran Sasso e Monti della Laga National Park. Prot. n. 0007804/17 | Collection M. Biondi, University of L’Aquila (Italy) | KJ962137 | requested |
Longitarsus suturellus (Duftschmid) | Asteraceae | OLI | GenBank | KU915636 | – | ||
Longitarsus tabidus (Fabricius) | Scrophulariaceae | OLI | GenBank | KX943424 | KX943424 | ||
Longitarsus zangherii Warchalowski | Asteraceae | MON | Italy, Abruzzo (TE), Prati di Tivo, 42°30'26.40"N 13°33'14.46"E, 1344 m a.s.l., 11.vii.2018, adult on Petasites sp. (Asteraceae) [det. M. Biondi, voucher db47] | Gran Sasso e Monti della Laga National Park. Prot. n. 0007403/18 | Collection M. Biondi, University of L’Aquila (Italy) | requested | requested |
To assess the association between phylogeny and patterns of host use, we used information on host plants for each species of Longitarsus from field observations over many years, and from a critical analysis of information reported in the literature (
Phylogenetic relationships among plant families were discussed according to
Total genomic DNA was extracted from preserved specimens using either a standard high-salt protocol (
Multiple sequence alignment was performed with MAFFT v.7 (
Bayesian Inference analyses were performed in MrBayes 3.2.6 (
Phylogenetic results were summarised using the ML tree and reporting for each node both BS and BPP from the Bayesian analysis. Nodes with bootstrap values (BS) between 70 and 90% and Bayesian posterior probability (BPP) between 0.95 and 0.98 were considered as supported, and those with BS greater than 90% and BPP greater than 0.98 as highly supported.
Host plants information is available for 165 out of 197 Longitarsus species known for the Western Palaearctic region. More than 96% of the species for which hosts are known, are specialized, either oligophagous or monophagous. The remaining species are generally considered as polyphagous (Fig.
Among the 52 Longitarsus species used in our molecular phylogenetic analyses (Table
Phylogenetic analyses based on ML and BI methods gave consistent results and identified the same supported clades (Fig.
Maximum Likelihood phylogenetic tree of 52 species of Longitarsus based on concatenated cox1 and 16S DNA sequences. Circles in correspondence of nodes represent bootstrap support (BS, upper half) and posterior probability (BPP, bottom half) from Bayesian analysis: black for BS > 90 and BPP > 0.98; grey for BS of 70–90% and BPP of 0.95–0.98; white for BS of 50–70% only for nodes supported by Bayesian analysis. Abbreviations: POL = polyphagous; ? = host plants unknown.
In agreement with the host phylogenetic conservatism hypothesis, we recovered a strict association between most of the recovered Longitarsus clades and specific plant families, except for species associated with Boraginaceae (Fig.
The two species associated with Convolvulaceae, L. nigrocillus, and L. pellucidus, cluster together with high support in clade N. The polyphagous species, L. atricillus and L. aeneicollis, plus L. bedelii, for which no host plants are known, form the highly supported clade M. On the other hand, clades grouping species associated with Boraginaceae are distant in the phylogenetic tree: clade D with six species and the isolated branch of L. curtus are included in clade A, whereas clade O with four species occupies a basal position of the phylogenetic tree together with other four species with poorly resolved phylogenetic position (L. fallax, L. quadriguttatus, L. lateripunctatus, L. linnaei).
Overall the phylogenetic tree of Western Palaearctic Longitarsus shows a decrease of statistical support from the tips to the root, with highly supported terminal clades and weakly supported basal relationships (Fig.
Ideally, for a conclusive assessment of phylogenetic conservatisms in host-plant association between closely related Longitarsus clades and closely related plant families we would require well-resolved phylogenies for both insects and plants at all taxonomic levels. While limited uncertainty exists for interrelationships between plant families (e.g., over the exact placement of Boraginaceae family (The APG 2016)), our molecular phylogenetic analysis only provides a first appraisal of relationships between Western Palaearctic Longitarsus. To assess whether the pattern of basal polytomy we observed (Fig.
In this study, we provided first evidence that host-use patterns are phylogenetically constrained in Western Palaearctic Longitarsus. Despite the limited set of species analysed, we found a clear association between closely related Longitarsus species and specific plant families (Plantaginaceae, Asteraceae, Scrophulariaceae, and Convolvulaceae). However, relationships between clades of species were poorly resolved thus preventing the assessment of whether all Longitarsus clades associated with a specific plant family, or to related plant families, represent a single lineage. Such a relationship is unlikely for those Longitarsus species feeding on Boraginaceae which were resolved in unrelated clades. A better understanding of the phylogenetic relationships between Longitarsus species associated with Boraginaceae is of great interest also from a biogeographical point of view. In fact, two groups of species feeding on Boraginaceae and sharing a number of striking morphological features show a disjunct Mediterranean-South African distribution (
We are grateful to Caroline S. Chaboo, Anthony Deczynski, and Chris Reid for their suggestions, that have improved the early version of the manuscript. We thank Gran Sasso e Monti della Laga National Park and Sirente Velino Natural Park that allowed the collection of specimens used in this work. DS is supported by the program ‘Rita Levi Montalcini’ (MIUR, Ministero dell’Istruzione, dell’Università e della Ricerca) for the recruitment of young researchers at the University of L’Aquila.