Genetic Diversity and Population Structure of Busseola segeta Bowden (Lepidoptera; Noctuidae): A Case Study of Host Use Diversification in Guineo-Congolian Rainforest Relic Area, Kenya

Phylogeography and Population Structure of the Mediterranean Corn Borer, Sesamia nonagrioides (Lepidoptera: Noctuidae), Across Its Geographic Range

Sesamia nonagrioides (Lefèbvre) (Lepidoptera: Noctuidae), is a widespread insect pest in Africa, the Middle East, and Europe. However, its pest status varies across its distribution range. It is a major pest of maize in Europe and of sugarcane in Iran. In Africa, it is a major pest of maize in West Africa but not considered as a pest in East Africa. Recent surveys conducted in 2015 recorded S. nonagrioides to be a major pest of sugarcane in Ethiopia and reported the species for the first time in Botswana, outside its known geographic range. The genetic relationship of these records with the previously recorded population of S. nonagrioides was investigated using the cytochrome oxidase subunit I region of the mitochondrial genome. In total, 113 individuals across the geographic range of the species were analyzed and 63 haplotypes were identified. Phylogenetic analysis separated the populations into two clades with no distinct geographic distribution pattern. The genetic differentiation was also not associated with host plants and geographic distances. Results of the molecular analysis revealed the long-time establishment of S. nonagrioides population in Botswana and identified the newly recorded sugarcane population from Ethiopia as part of the wild host population in the country. The phylogeographic patterns observed among population of S. nonagrioides have probably been shaped by Pleistocene's climatic oscillations and geographic range expansions from different refugia with secondary contact and admixture. Possible reasons for the host-plant expansion by the Ethiopian population are discussed.

Identification and Distribution of Haplotypes of Diaphorina citri (Hemiptera: Liviidae) in Jamaica and the Caribbean

Diaphorina citri Kuwayama (Hemiptera: Psyllidae), also known as the Asian citrus psyllid, is a vector of the citrus huanglongbing (HLB) disease. D. citri transmits all three known strains of the HLB pathogen: Candidatus Liberibacter africanus, Candidatus Liberibacter americanus, and Candidatus Liberibacter asiaticus. The study involved 92 psyllids representing the Caribbean Basin and reference samples representing countries within Asia, North America, and South America. This study was aimed at characterizing D. citri on a molecular level in order to determine the haplotype diversity and uniqueness within Jamaica and the Caribbean Basin. D. citri-specific primers were used to amplify an 821 bp gene fragment from the mitochondrial cytochrome c oxidase subunit I gene (mtCOI). The statistical parsimony program, TCS, was used to determine the 12 haplotypes found within the Caribbean, with haplotypes H2 and H7 being the most prominent. The H2 haplotype was found to belong to the South Western Asia group originating from India. H2 represented 54% of the sequenced samples and dominated the Greater Antilles, 22% were grouped as H7, dominating the Lesser Antilles, while the remaining 24% of the sequences were grouped in the remaining 10 haplotypes and were variants seen within the Greater and Lesser Antilles.

Relationships of Reproductive Traits With the Phylogeny of the African Noctuid Stem Borers

The display of the reproductive behavior in most noctuid Lepidoptera follows a diel periodicity and is limited to a precise period of either the day or the night. These behavioral traits and the sex pheromone chemistry can be species specific and thus might be linked to the phylogeny. The objective of this study was to test the relationship of these reproductive traits with phylogeny. The study was undertaken using eight closely related species of noctuid stem borers, which are easy to rear under artificial conditions, namely, Busseola fusca, B. nairobica, B. sp. nr. segeta, Manga melanodonta, M. sp. nr. nubifera, Pirateolea piscator, Sesamia calamistis, and S. nonagrioides. For each species, the adult emergence period, the mating time, and the oviposition period were estimated, referred as biological traits. The components of the sex pheromones emitted by the females of each species were also analyzed by gas chromatography-mass spectrometry. Among the biological traits measured, only those linked to the oviposition pattern (timing and egg loads per night) were significantly correlated with the phylogeny of these species. For the sex pheromone components, among the 13 components identified in all species, only four, namely, Z9-tetradecenyl acetate (Z9-TDA), Z11-TDA, E11-TDA, and Z11-hexadecenyl acetate (Z11-HDA), showed the highest significant correlations with the phylogeny. These results suggest that among the different reproductive traits evaluated, only few are phylogenetically constrained. Their involvement in the reinforcement of ecological speciation in noctuid stem borers is discussed.

Ecology of the African Maize Stalk Borer, Busseola fusca (Lepidoptera: Noctuidae) with Special Reference to Insect-Plant Interactions

Busseola fusca (Lepidoptera: Noctuidae) is an important pest of maize and sorghum in sub-Saharan Africa. One century after its first description by Fuller in 1901, inaccurate information based on earlier reports are still propagated on its distribution (e.g., absent from the lower altitudes in East Africa) and host plant range (e.g., feeding on a large range of wild grass species). This review provides updated information on the biology, distribution and genetics of B. fusca with emphasis on insect-plant interactions. Related to this, new avenues of stem borer management are proposed.