Bactrocera dorsalis s.s. (Hendel) and B. papayae Drew & Hancock, are invasive pests belonging to the B. dorsalis complex. Their species status, based on morphology, is sometimes arguable. Consequently, the existence of cryptic species and/or population isolation may decrease the effectiveness of the sterile insect technique (SIT) due to an unknown degree of sexual isolation between released sterile flies and wild counterparts. To evaluate the genetic relationship and current demography in wild populations for guiding the application of area-wide integrated pest management using SIT, seven microsatellite-derived markers from B. dorsalis s.s. and another five from B. papayae were used for surveying intra- and inter-specific variation, population structure, and recent migration among sympatric and allopatric populations of the two morphological forms across Southern Thailand and West Malaysia.
To determine the geographic origin of the black fly Simulium suzukii on Okinawa Island, Japan, macrogenomic profiles derived from its polytene chromosomes were compared with those of mainland and other insular populations of S. suzukii and of the isomorphic Simulium tani species complex. The Okinawan population is a chromosomally unique cytoform, designated 'D,' which is essentially monomorphic and differs by about 27 fixed rearrangements from the chromosomal standard sequence for the subgenus Simulium and by two fixed differences from its nearest known relative, representing the type of S. suzukii, on the main islands of Japan. Chromosomal band sequences revealed two additional, sympatric cytoforms of S. suzukii, designated 'A' and 'B,' each with species status, in Korea, and a third cytoform, designated 'C,' on Hokkaido, Japan. A new cytoform, 'K,' of S. tani from Malaysia, representing the type of S. tani, is more closely related to cytoforms in Thailand, as are populations from Taiwan previously treated as S. suzukii but more closely aligned with S. tani and newly recognized as cytoform 'L' of the latter nominal species. Rooting of chromosomal band sequences by outgroup comparisons allowed directionality of chromosomal rearrangements to be established, enabling phylogenetic inference of cytoforms. Of 41 macrogenomic rearrangements discovered in the five new cytoforms, four provide evidence for a stepwise origin of the Okinawan population from populations characteristic of the main islands of Japan. The macrogenomic approach applied to black flies on Okinawa Island illustrates its potential utility in defining source areas for other species of flies including those that might pose medical and veterinary risks.
An integrative taxonomic analysis is used to delimit and describe three new species of Pseudocalotoes from the sky island archipelago of the Banjaran (=mountain range) Titiwangsa of Peninsular Malaysia. Pseudocalotes drogon sp. nov., from Fraser's Hill, Pahang is basal to the sister species P. larutensis from Bukit Larut, Perak in the Banjaran Bintang and the new species P. rhaegal sp. nov. from Cameron Highlands, Pahang. Pseudocalotes drogon sp. nov. is differentiated from all other species of Psuedocalotes by having the combination of a flat rostrum; seven postrostrals; an interparietal; 11 circumorbitals; five canthals; 7-10 superciliaries; one scale between the rostral and nasal; nine supralabials; eight infralabials; 10 postnasal-suborbital scales; four postmentals; five or six sublabials; five or six chinshields; 47 smooth, wide, gular scales; weak transverse gular and antehumeral folds; two enlarged scales between the ear and eye; enlarged upper and lower posttemporals; a single enlarged supratympanic; no enlarged postrictals; three large scales bordering the dorsal margin of the ear opening; large pretympanic scales; eight scales in the nuchal crest not separated by a gap; enlarged vertebral scales extending to the tip of the tail; keeled and non-plate-like scales on flanks; 51 midbody scales; midventrals smaller than dorsals; 19 subdigital lamellae on the fourth finger; 23 subdigital lamellae on the fourth toe; preaxial scales on third toe enlarged and spinose; subdigital lamellae not unicarinate; HW/HL 0.52; HL/SVL 0.31; no elbow or knee patches; and a male dewlap color of lime-green bearing a central yellow spot. Pseudocalotes rhaegal sp. nov. is differentiated from all other Psuedocalotes by having the combination of a convex rostrum; 6-8 postrostrals; an interparietal; nine or 10 circumorbitals; five canthals; 7-10 superciliaries; one or two scales between the rostral and nasal scales; eight or nine supralabials; seven or eight infralabials; 11 or 12 postnasal-suborbital scales; four postmentals; four or five chinshields; 40-45 smooth, wide, gular scales; no transverse gular fold; a weak antehumeral fold; three or four enlarged scales between the ear and eye; an enlarged upper and lower posttemporal; an enlarged supratympanic; no enlarged postrictals; no large scales bordering the upper margin of the ear opening or in the pretympanic region; 6-8 enlarged nuchal crest scales not separated by a gap; enlarged vertebral scales extending to the base of the tail; weakly keeled, non-plate-like scales on the flanks; 52-58 midbody scales; midventrals smaller than dorsals; 19-21 subdigital lamellae on the fourth finger; 22-26 subdigital lamellae on the fourth toe; preaxial scales on the third enlarged and rounded; subdigital lamellae not unicarinate; HW/HL 0.50-0.54; HL/SVL 0.28-0.30; no elbow or knee patches; and female dewlap color yellow bearing a purple base. The analyses also indicated that the new species, P. viserion sp. nov. from Genting Highlands, Pahang in the southern section of the Banjaran Titiwangsa is the sister species of P. flavigula from Cameron Highlands 121 km to the north and can be separated from all other species of Psuedocalotes by having the combination of three postrostrals; 10 circumorbitals; four or five canthals; 5-7 superciliaries; rostral and nasals in contact; supralabials contacting the nasal; six or seven supralabials; six or seven infralabials; two or three postmentals; 47 or 48 smooth, flat, gular scales; three chinshields; weak transverse gular and antehumeral folds; two enlarged scales between the ear and eye; an enlarged upper and lower posttemporal; an enlarged supratympanic; no enlarged postrictals; 7-9 nuchal crest scales lacking gaps and not extending beyond midbody; weakly keeled and plate-like scales on the flanks; 35-38 midbody scales; ventrals smaller than dorsals; 22 or 23 subdigital lamellae on the fourth finger; 26 or 27 subdigital lamellae on the fourth toe; preaxial scales on the third toe not modified; subdigital scales not unicarinate; HW/HL 0.62; no white marking below the eye; dewlap in males yellow; and no elbow or knee patches. Pseudocalotes rhaegal sp. nov. most likely occurs in syntopy with P. flavigula in Tanah Rata at Cameron Highlands and its discovery adds to a growing body of literature detailing the recent descriptions of several new, upland, closely related, sympatric species in Peninsular Malaysia. Another new population referred to here as Pseudocalotes sp. nov. from the Hala-Bala Wildlife Sanctuary, Betong District, Yala Province, Thailand is discussed. The discovery and description of these three new Pseudocalotes from the upland regions of Peninsular Malaysia continues to underscore the remarkably high herpetological diversity and ecological complexity in this sky island archipelago that is still underestimated, unappreciated, and unprotected.
Morphological and host-plant relationship studies were conducted to differentiate two sympatric populations of brown planthopper (BPH), Nilaparvata lugens, one from rice (Oryza sativa) and the other from Leersia hexandra, a weed grass. In morphometric studies based on esterase activities, an UPGMA dendrogram using 17 quantitative morphological characters, including stridulatory organs (courtship signal-producing organs) between two sympatric populations of N. lugens, one from rice and the other from L. hexandra, a weed grass revealed that both populations were separated from each other. An out-group, N. bakeri, was found to be completely different from the two sympatric populations of N. lugens. Rice plants were best suited for the establishment of the rice-infesting population, and L. hexandra was a favourable host for the Leersia-infesting population. The individuals derived from one host did not thrive on the other host, as shown by a significant reduction in survival and nymphal development, ovipositional preferences, ovipositional response, and egg hatchability. Therefore, morphological and host-plant relationship studies indicate that rice-associated population with high esterase activities and L. heaxandra-associated population with low esterase activities are two closely related sibling species.
We access the molecular diversity of the black fly Simulium nobile De Mejiere, using the universal cytochrome c oxidase subunit I (COI) barcoding gene, across its distributional range in Southeast Asia. Our phylogenetic analyses recovered three well-supported mitochondrial lineages of S. nobile, suggesting the presence of cryptic species. Lineage A is composed of a population from Sabah, East Malaysia (Borneo); lineage B represents the type population from Java, Indonesia; and lineage C includes populations from the mainland of Southeast Asia (Peninsular Malaysia and Thailand). The genetic variation of lineage C on the mainland is greater than that of lineages A and B on the islands of Borneo and Java. Our study highlights the value of a molecular approach in assessing species status of simuliids in geographically distinct regions.
Haemonchus species are major gastro-intestinal parasites affecting ruminants across the world. The present study aimed to assess the sympatric species distribution, genetic diversity, population structure and frequency of β-tubulin isotype 1 alleles associated with benzimidazole resistance. Internal transcribed spacer 2 (ITS2) sequences revealed three sympatric species of Haemonchus, H. contortus, H. placei and H. longistipes with 12 distinct genotypes circulating among ruminant hosts in Pakistan. High genetic variability was observed in Pakistani Haemonchus isolates at nicotine amide dehydrogenase subunit 4 (ND4) and cytochrome oxidase subunit 1 (COI) gene loci. Intra-population diversity parameters were higher in H. contortus isolates than H. placei. Phylogenetic analysis of ND4 and COI sequences did not reveal clustering of haplotypes originating from a particular host indicating high rate of gene flow among Haemonchus parasites infecting sheep, goat and cattle in Pakistan. ND4 and COI haplotypes from Pakistan were compared to sequences of Haemonchus isolates from 11 countries to elucidate the population structure. Multidimensional scaling (MDS) plot of pairwise FST derived from 531 ND4 haplotypes revealed clustering together of H. contortus from Pakistan, China, Malaysia and Italy while the isolates from Yemen and United States were found to be genetically distinct. With respect to H. placei, isolates from Pakistan were found to be genetically differentiated from isolates of other countries. The tests for selective neutrality revealed negative D statistics and did not reveal significant deviations in Pakistani Haemonchus populations while significant deviation (P < 0.05) was observed in Brazilian and Chinese H. contortus populations. Median Joining (MJ) network of ND4 haplotypes revealed Yemenese H. contortus being closer to H. placei cluster. β-tubulin isotype 1 genotyping revealed 7.86% frequency of Y allele associated with benzimidazole resistance at F200Y locus in Pakistani Haemonchus isolates.