Three cryptic species in Asecodes (Förster) (Hymenoptera, Eulophidae) parasitizing larvae of Galerucella spp. (Coleoptera, Chrysomelidae), including a new species

Hansson, Christer; Hambäck, Peter A.

doi:10.3897/jhr.30.4279

Cited by 15 publications

(10 citation statements)

References 6 publications

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“…It is possible to conclude that A. lucens should be split at least into three species but additional data may strengthen the indication of further splits; the species delimitation analysis suggested 3–5 species. The molecular data have been confirmed by morphological studies that found differences in wing patterns among at least 3 taxa [61]. Comparisons with type specimens of available (synonymized) names suggested the identity of two taxa, A. lucens parasitizing G. sagittariae and A. parviclava (Thomson) parasitizing G. tenella , G. calmariensis and G. pusilla .…”

Section: Discussionmentioning

confidence: 71%

“…Comparisons with type specimens of available (synonymized) names suggested the identity of two taxa, A. lucens parasitizing G. sagittariae and A. parviclava (Thomson) parasitizing G. tenella , G. calmariensis and G. pusilla . A third species, parasitizing G. lineola , represents a new species named A. lineophagum Hansson & Hambäck [61]. There were no morphological characters supporting a further subdivision of A. parviclava .…”

Section: Discussionmentioning

confidence: 99%

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Bayesian species delimitation reveals generalist and specialist parasitic wasps on Galerucella beetles (Chrysomelidae): sorting by herbivore or plant host

et al. 2013

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BackgroundTo understand the ecological and evolutionary consequences of species interactions in food webs necessitates that interactions are properly identified. Genetic analyses suggest that many supposedly generalist parasitoid species should rather be defined as multiple species with a more narrow diet, reducing the probability that such species may mediate indirect interactions such as apparent competition among hosts. Recent studies showed that the parasitoid Asecodes lucens mediate apparent competition between two hosts, Galerucella tenella and G. calmariensis, affecting both interaction strengths and evolutionary feedbacks. The same parasitoid was also recorded from other species in the genus Galerucella, suggesting that similar indirect effects may also occur for other species pairs.MethodsTo explore the possibility of such interactions, we sequenced mitochondrial and nuclear genetic markers to resolve the phylogeny of both host and parasitoid and to test the number of parasitoid species involved. We thus collected 139 Galerucella larvae from 8 host plant species and sequenced 31 adult beetle and 108 parasitoid individuals.ResultsThe analysis of the Galerucella data, that also included sequences from previous studies, verified the five species previously documented as reciprocally monophyletic, but the Bayesian species delimitation for A. lucens suggested 3–4 cryptic taxa with a more specialised host use than previously suggested. The gene data analyzed under the multispecies coalescent model allowed us to reconstruct the species tree phylogeny for both host and parasitoid and we found a fully congruent coevolutionary pattern suggesting that parasitoid speciation followed upon host speciation.ConclusionUsing multilocus sequence data in a Bayesian species delimitation analysis we propose that hymenopteran parasitoids of the genus Asecodes that infest Galerucella larvae constitute at least three species with narrow diet breath. The evolution of parasitoid Asecodes and host Galerucella show a fully congruent coevolutionary pattern. This finding strengthens the hypothesis that the parasitoid in host search uses cues of the host rather than more general cues of both host and plant.

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Section: Discussionmentioning

confidence: 71%

Section: Discussionmentioning

confidence: 99%

Bayesian species delimitation reveals generalist and specialist parasitic wasps on Galerucella beetles (Chrysomelidae): sorting by herbivore or plant host

et al. 2013

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“…In the north, where G. pusilla is lacking, G. tenella and G. calmariensis often occur close together. Larvae of all three Galerucella species are attacked by the parasitic wasp A. parviclava Thompson (Hymenoptera: Eulophidae) (Hambäck et al., ; Hansson & Hambäck, ). The three Galerucella species are the only known hosts for A .…”

Section: Methodsmentioning

confidence: 99%

Selection by parasitoid females among closely related hosts based on volatiles: Identifying relevant chemical cues

Fors

Mozūraitis

Blažytė‐Čereškienė

et al. 2018

Ecology and Evolution

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Parasitoid fitness is influenced by the ability to overcome host defense strategies and by the ability of parasitoid females to select high‐quality host individuals. When females are unable to differentiate among hosts, their fitness will decrease with an increasing abundance of resistant hosts. To understand the effect of mixed host populations on female fitness, it is therefore necessary to investigate the ability of female parasitoids to select among hosts. Here, we used behavioral assays, headspace volatile collection, and electrophysiology to study the ability of Asecodes parviclava to use olfactory cues to select between a susceptible host (Galerucella calmariensis) and a resistant host (Galerucella pusilla) from a distance. Our studies show that parasitoid females have the capacity to distinguish the two hosts and that the selection behavior is acquired through experiences during earlier life stages. Further, we identified two volatiles (α‐terpinolene and [E]‐β‐ocimene) which amounts differ between the two plant–herbivore systems and that caused behavioral and electrophysiological responses. The consequence of this selection behavior is that females have the capacity to avoid laying eggs in G. pusilla, where the egg mortality is higher due to much stronger immune responses toward A. parviclava than in larvae of G. calmariensis.

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“…The most recent divergence date for Galerucella is estimated to 77 000 years ago for G. pusilla and G. calmariensis , and the speciation of Asecodes seems to be following the speciation of the hosts (Hambäck et al . ; Hansson & Hambäck ). Differences in immune response in G. pusilla and G. calmariensis have previously been observed (Fors et al .…”

Section: Introductionmentioning

confidence: 99%

“…Previous genetic studies indicate that A. parviclava could be at an early stage of further speciation, making Galerucella-Asecodes a useful model system for investigating evolution of resistance and counter-resistance mechanisms. The most recent divergence date for Galerucella is estimated to 77 000 years ago for G. pusilla and G. calmariensis, and the speciation of Asecodes seems to be following the speciation of the hosts Hansson & Hamb€ ack 2013). Differences in immune response in G. pusilla and G. calmariensis have previously been observed (Fors et al 2014), as well as among population differences in parasitism rate (i.e.…”

Section: Introductionmentioning

confidence: 99%

Geographic variation and trade‐offs in parasitoid virulence

Fors

Márkus

Theopold

et al. 2016

Journal of Animal Ecology

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Summary1. Host-parasitoid systems are characterized by a continuous development of new defence strategies in hosts and counter-defence mechanisms in parasitoids. This co-evolutionary arms race makes host-parasitoid systems excellent for understanding trade-offs in host use caused by evolutionary changes in host immune responses and parasitoid virulence. However, knowledge obtained from natural host-parasitoid systems on such trade-offs is still limited. 2. In this study, the aim was to examine trade-offs in parasitoid virulence in Asecodes parviclava (Hymenoptera: Eulophidae) when attacking three closely related beetles: Galerucella pusilla, Galerucella calmariensis and Galerucella tenella (Coleoptera: Chrysomelidae). A second aim was to examine whether geographic variation in parasitoid infectivity or host immune response could explain differences in parasitism rate between northern and southern sites. 3. More specifically, we wanted to examine whether the capacity to infect host larvae differed depending on the previous host species of the parasitoids and if such differences were connected to differences in the induction of host immune systems. This was achieved by combining controlled parasitism experiments with cytological studies of infected larvae. 4. Our results reveal that parasitism success in A. parviclava differs both depending on previous and current host species, with a higher virulence when attacking larvae of the same species as the previous host. Virulence was in general high for parasitoids from G. pusilla and low for parasitoids from G. calmariensis. At the same time, G. pusilla larvae had the strongest immune response and G. calmariensis the weakest. These observations were linked to changes in the larval hemocyte composition, showing changes in cell types important for the encapsulation process in individuals infected by more or less virulent parasitoids. 5. These findings suggest ongoing evolution in parasitoid virulence and host immune response, making the system a strong candidate for further studies on host race formation and speciation.

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Three cryptic species in Asecodes (Förster) (Hymenoptera, Eulophidae) parasitizing larvae of Galerucella spp. (Coleoptera, Chrysomelidae), including a new species

Cited by 15 publications

References 6 publications

Bayesian species delimitation reveals generalist and specialist parasitic wasps on Galerucella beetles (Chrysomelidae): sorting by herbivore or plant host

Bayesian species delimitation reveals generalist and specialist parasitic wasps on Galerucella beetles (Chrysomelidae): sorting by herbivore or plant host

Selection by parasitoid females among closely related hosts based on volatiles: Identifying relevant chemical cues

Geographic variation and trade‐offs in parasitoid virulence

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