Comparative cytogenetics and derived phylogenic relationship among Sitophilus grain weevils (Coleoptera, Curculionidae, Dryophthorinae)

Authors: SILVA, A - Universidade Federal De Vicosa; BRAGA, L - Universidade Federal De Vicosa; CORREA, A - Universidade De Sao Paulo; HOLMES, V - Texas A&M University; JOHNSTON, J - Texas A&M University; Oppert, Brenda; GUEDES, R.N. - Universidade Federal De Vicosa; TAVARES, M - Universidade Federal De Vicosa

Submitted to: Comparative Cytogenetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/13/2018
Publication Date: 7/2/2018
Citation: Silva, A.A., Braga, L.S., Correa, A.S., Holmes, V.R., Johnston, J.S., Oppert, B.S., Guedes, R.C., Tavares, M.G. 2018. Comparative cytogenetics and derived phylogenic relationship among Sitophilus grain weevils (Coleoptera, Curculionidae, Dryophthorinae). Comparative Cytogenetics. 12(2):223-245. https://doi.org/10.3897/CompCytogen.v12i2.26412.
DOI: https://doi.org/10.3897/CompCytogen.v12i2.26412

Interpretive Summary: The study of chromosomes as it relates to genome size is important in advance of genome sequencing studies and provides important insights into the evolutionary relationships of species of interest. Grain weevil species within the Sitophilus genus have economic importance as pest species of stored products, and the relationship among these weevil species remains controversial and are largely based on single DNA fragment analyses. Chromosome analyses in four Sitophilus grain weevil species (granary, tamarind, rice, and maize weevils) revealed that maize and rice weevils have similar and larger genome sizes, with the granary weevil genome intermediate, and the tamarind weevil with the smallest genome. A study of evolutionary relatedness indicated that the maize and rice weevils are more closely related, and the granary and tamarind weevils are more related to each other and share a common recent ancestor. These data will be used in genome sequencing and further evolutionary analyses of stored product weevils.

Technical Abstract: Cytogenetic characteristics and genome size are important aspects of genomic organization and powerful tools for species characterization and identification of cryptic species allowing important insights in the phylogenetic relationships and evolutionary relationship of species of interest. Grain weevil species within the the Sitophilus genus are a worthy target of attention due to their economic importance as pest species of stored products, and also as source of (archeological) information of human history and past urban environments, and grain and trade routes. Moreover, the phylogenetic relationship among these weevil species remains controversial and largely based single DNA fragment analyses. Therefore, cytogenetic analyses and genome size determinations were performed for the four Sitophilus grain weevil species, namely the granary weevil Sitophilus granarius (L.), the tamarind weevil S. linearis Schoenherr., the rice weevil S. oryzae (L.), and the maize weevil S. zemais Motsch. The karyotype of each of the species was described and the nuclear DNA content of these species is not proportionally related to either chromosome number or heterochromatin among. Maize and rice weevils exhibited similar and larger genome sizes (0.730±0.003 pg and 0.786±0.003 pg respectively), followed by the granary weevil with significantly smaller genome size (0.553±0.003 pg), and the tamarind weevil with the smallest genome size (0.440±0.001 pg). Parsimony phylogenetic analysis agreed with the descriptive analysis of Sitophilus karyotype, indicating that S. zeamais and S. oryzae are phylogenetically closer than S. granarius and S. linearis. The latter two species, the granary and tamarind weevils, are closer related to each other and exhibit a common and recent ancestral.