Gene rearrangement in the mitogenome of whiteflies (Hemiptera: Aleyrodinae) along with their phylogeny and characterization of complete mitogenome of Aleurodicus rugioperculatus.

BACKGROUND: Mitochondrial genome rearrangements have been used for defining evolutionary relationships, but there have been incidences of convergences at different taxonomic levels. To gain new insights into whitefly mitogenome evolution, gene arrangement and phylogeny, we sequenced the complete mitogenome of Aleurodicus rugioperculatus (Aleyrodidae: Aleurodicinae) and conducted a comparative analysis with the previously published mitogenomes across the family Aleyrodidae. METHODS AND RESULTS: The complete mitogenome of Aleurodicus rugioperculatus was generated by Next generation sequencing method. It is 15,060 bp circular molecule with 86.5 A + T and 5.5% G + C content. It contains 37 genes (13 PCGs, two rRNAs, 22 tRNAs) and a non-coding control region (CR). Comparative analysis of codon usage indicated that the subfamily Aleyrodinae have weaker bias than Aleurodicinae. Bayesian Inference (BI) and Maximum Likelihood (ML) phylogenetic analyses yielded similar topologies supporting the monophyly of Aleyrodinae and Aleurodicinae. The gene order of 13 whiteflies was compared with ancestor to examine the plesiomorphies, synapomorphies and autapomorphies. We identified five gene blocks (I-V) in the whitefly ancestor that are shared plesiomorphies retained in different whitefly lineages. Gene block I is conserved in all whiteflies except three species. Conversely, we detected 83 derived gene boundaries within the family. Mapping these gene boundaries onto a phylogenetic tree revealed that 16 were symplesiomorphies for two subfamilies; 9 were synapomorphies between the species, and 28 autapomorphies for individual species. CONCLUSIONS: Comparative analyses of gene order of whiteflies revealed the derived gene boundaries which can be further investigated with more mitogenome data to examine the genome evolution in whiteflies.

An annotated checklist of earwigs (Dermaptera) of South India with two new records from India.

The checklist of earwigs occurring in South India,viz., Andhra Pradesh, Karnataka, Kerala, Tamil Nadu and Telangana, was compiled from published literature and augmented by collecting efforts between 2020 and 2022. A total of 102 species belonging to 45 genera and eight families are listed herein from South India. Specimens representing 29 species were collected from the South Indian states during 20202022 surveys, of whichDendroiketes corticinusandChaetospania anderssonirepresent two new records for India. The highest number of species was recorded from Tamil Nadu (79 species), followed by Karnataka (39 species) and Kerala (26 species), while the least number were from Telangana (6) and Andhra Pradesh (4 species). The records indicated that the South Indian states, which cover a significant portion of the Western Ghats of India (Karnataka, Kerala and Tamil Nadu), are more diverse than previously indicated.

The evolutionary process of invasion in the fall armyworm (Spodoptera frugiperda).

The fall armyworm (FAW; Spodoptera frugiperda) is one of the major agricultural pest insects. FAW is native to the Americas, and its invasion was first reported in West Africa in 2016. Then it quickly spread through Africa, Asia, and Oceania, becoming one of the main threats to corn production. We analyzed whole genome sequences of 177 FAW individuals from 12 locations on four continents to infer evolutionary processes of invasion. Principal component analysis from the TPI gene and whole genome sequences shows that invasive FAW populations originated from the corn strain. Ancestry coefficient and phylogenetic analyses from the nuclear genome indicate that invasive populations are derived from a single ancestry, distinct from native populations, while the mitochondrial phylogenetic tree supports the hypothesis of multiple introductions. Adaptive evolution specific to invasive populations was observed in detoxification, chemosensory, and digestion genes. We concluded that extant invasive FAW populations originated from the corn strain with potential contributions of adaptive evolution.

Molecular diversity of Sesamia inferens (Walker, 1856) (Lepidoptera: Noctuidae) from India.

Pink stem borer, Sesamia inferens (Walker, 1856) (Lepidoptera: Noctuidae) is reported to infest many graminaceous crops and cause significant losses. S. inferens cause damage by killing the central shoot and producing a characteristic symptom called "dead heart". Since graminaceous crops are an important source of food for humans and their livestock, impetus should be given on designing efficient management strategies against pink stem borer. The study of genetic variability of pest populations enables to interpret the ecological investigations correctly and also helps to comprehend the dissimilar response of pest to management tactics. The present study was undertaken to evaluate the diversity in S. inferens populations using mitochondrial cytochrome oxidase subunit I sequences from India, Pakistan, China and Indonesia. Analysis revealed a very low nucleotide diversity in Indian populations (π = 0.00981), as compared to a high nucleotide diversity in the sequences outside India (π = 0.4989). The phylogenetic analysis also did not show any clustering among populations within India and Pakistan. However, the nearest neighbour for the Indian and Pakistan population is a sequence from Indonesia followed by China indicating possible ancestral background. This is the maiden attempt to assess the molecular diversity of Indian populations in comparison to populations from other Asian countries. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-02678-y.

Transmission efficiency of Papaya ringspot virus by three aphid species.

The transmission efficiency of Papaya ringspot virus (PRSV) by three aphid vectors (i.e., Aphis gossypii, A. craccivora, and Myzus persicae) was studied. Efficiency was measured by single-aphid inoculation, group inoculation (using five aphids), duration of virus retention, and the number of plants following a single acquisition access period (AAP) to which the aphids could successfully transmit the virus. Single-aphid inoculation studies indicated that M. persicae (56%) and A. gossypii (53%) were significantly more efficient in transmitting PRSV than A. craccivora (38%). Further, in the former two species, the time required for initiation of the first probe on the inoculation test plant was significantly shorter compared to A. craccivora. PRSV transmission efficiency was 100% in all three species when a group of five aphids were used per plant. There was a perceptible decline in transmission efficiency as the sequestration period increased, although M. persicae successfully transmitted PRSV after 30 min of sequestration. A simple leaf-disk assay technique was employed for evaluating the transmission efficiency of three species of aphids. The results of leaf-disk assays also indicated that A. gossypii (48%) and M. persicae (56%) were more efficient PRSV vectors than A. craccivora. Using leaf-disk assays, the ability of individual aphids to inoculate PRSV serially to a number of plants was studied. Following a single AAP on an infected leaf, M. persicae was more efficient than the other two species with 52.5% transmission after the first inoculation access period (IAP). However, its inoculation efficiency significantly decreased with the second and subsequent IAPs. A. gossypii was able to transmit PRSV sequentially up to four successive leaf disks, but with significantly declining efficiency. Since A. gossypii is reported to be the numerically dominant vector in south India in addition to being a more efficient vector capable of inoculating PRSV to multiple plants, it should be the target vector for control strategies.