Genetic analysis of feeding preference in two related species of Altica (Coleoptera: Chrysomelidae: Alticinae)

Yang

2014

Sci Rep

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Host plant shifting of phytophagous insects can lead to the formation of host associated differentiation and ultimately speciation. In some cases, host plant specificity alone acts as a nearly complete pre-mating isolating barrier among insect populations. We here test whether effective pre-mating isolation and host-independent behavioral isolation have evolved under the condition of extreme host specilization using two sympatric flea beetles with incomplete post-mating isolation under laboratory conditions. Phylogenetic analysis and coalescent simulation results showed that there is a limited interspecific gene flow, indicating effctive isolation between these species. Three types of mating tests in the absence of host plant cues showed that strong host-independent behavioral isolation has evolved between them. We conclude that almost perfect assortative mating between these two extreme host specialists results from a combination of reduced encounter rates due to differential host preference and strong sexual isolation.

Section: Discussionmentioning

confidence: 91%

“…The insects were fed their respective host plants ( D. indica fed to AF and G. nepalens fed to AV) in growth chambers at 16:8 LD and 25°C181920. To eliminate the possible effects due to different physiology, virgin captive-bred offspring were used for no-choice tests.…”

Section: Methodsmentioning

confidence: 99%

Assortative mating between two sympatric closely-related specialists: inferred from molecular phylogenetic analysis and behavioral data

Yang

2014

Sci Rep

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“…Molecular phylogenetic analyses based on mitochondrial DNA sequence data have shown that these species are closely related (Kimura two-parameter distance 0.0303) (Zhai et al, 2007). Altica viridicyanea feeds exclusively on Geranium nepalens (Sweet) (Geraniaceae), whereas A. fragariae feeds on several plants belonging to the Rosaceae, among which the most common is Duchesnea indica (Andrews) (Yu et al, 1996;Wang et al, 2005;Xue et al, 2009). Each species also prefers the host plant where it performs better.…”

Section: Introductionmentioning

confidence: 99%

Reproductive barriers between two sympatric beetle species specialized on different host plants

J of Evolutionary Biology

Magalhães

et al. 2009

Knowledge on interspecific pre‐ and post‐zygotic isolation mechanisms provides insights into speciation patterns. Using crosses (F1 and backcrosses) of two closely related flea beetles species, Altica fragariae and A. viridicyanea, specialized on different hosts in sympatry, we measured: (a) the type of reproductive isolation and (b) the inheritance mode of preference and host‐specific performance, using a joint‐scaling test. Each species preferred almost exclusively its host plant, creating strong prezygotic isolation between them, and suggesting that speciation may occur at least partly in sympatry. Reproductive isolation was intrinsic between females of A. fragariae and either A. viridicyanea or F1 males, whereas the other crosses showed ecologically dependent reproductive isolation, suggesting ecological speciation. The genetic basis of preference and performance was at least partially independent, and several loci coded for preference, which limits the possibility of sympatric speciation. Hence, both ecological and intrinsic factors may contribute to speciation between these species.

“…The high rate of diversi cation among host-speci c herbivorous insects is thought to result from their shift and specialization to distinct host-plant species, creating conditions that promote reproductive isolation and contribute to the process of speciation [1][2][3]. A model herbivore that has been used to address questions about host plant specialization, reproductive isolation, and ecological speciation is the leaf beetle genus Altica (Coleoptera: Chrysomelidae) [4][5][6][7][8][9][10]. This group has undergone rapid divergence that is largely associated with host plant use.…”

Section: Introductionmentioning

confidence: 99%

The draft genome of the specialist flea beetle Altica viridicyanea (Coleoptera: Chrysomelidae) provides insight into host plant specialization

Niu

Segraves

et al. 2020

Preprint

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Background Altica (Coleoptera: Chrysomelidae) is a highly diverse and taxonomically challenging flea beetle genus that has been used as a model system in which to address questions related to host plant specialization, reproductive isolation, and ecological speciation. To further evolutionary studies in this important group, here we present a high-quality draft genome of a representative specialist, Altica viridicyanea, the first Alticinae genome and the fourth chrysomelid genome reported thus far. Results The genome is 864.8 Mb and consists of 4,490 scaffolds with a N50 size of 557 kb, which covered 98.6% complete and 0.4% partial insect Benchmarking Universal Single-Copy Orthologs. Repetitive sequences accounted for 62.9% of the assembly, and a total of 17,730 protein-coding gene models and 2,462 non-coding RNA models were predicted. To provide insight into host plant specialization of this monophagous species, we examined the key gene families involved in chemosensation, detoxification of plant secondary chemistry, and plant cell wall-degradation. Conclusions The high-quality genome assembled in this work provides an important resource for further studies on host plant adaptation and functionally affiliated genes. Moreover, this work also opens the way for comparative genomics studies among closely related Altica species, which may provide insight into the molecular evolutionary processes that occur during ecological speciation.