Comparison of Landmark- and Outline-Based Geometric Morphometrics for Discriminating Mosquito Vectors in Ratchaburi Province, Thailand

2019

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Abstract. Chaiphongpachara T. 2019. Outline-based geometric morphometric analysis to identify two Anopheles and three Culex mosquitoes in Thailand. Biodiversitas 20: 1866-1872. Geometric morphometric (GM) techniques have become popular for applications in entomology studies, especially mosquitoes. Outline-based methods (OTLs) are one such form of GM technique used to analyze pseudo-landmarks on contours or boundary outlines. This study investigated the efficacy of an OTL to distinguish two species of Anopheles mosquitoes including An. epiroticus and An. subpictus s.l. and three species of Culex mosquitoes, including Cx. quinquefasciatus, Cx. visnui and Cx. whitmorei in Thailand and compared outlines, including internal outline 1 (IOL1), internal outline 2 (IOL2) and external outline (EOL) within the mosquito wing to assess the optimal outline for analysis. The results indicated that OTLs were highly effective with certain species and each outline had the potential difference for identification. For size analysis, An. epiroticus had a mean perimeter length of IOL2 and EOL length larger than An. subpictus. Different sizes between species was found in IOL1, which was statistically significant after Bonferroni test (p < 0.05). Culex size analysis of IOL2 and EOL demonstrated a statistical difference for all species while size difference patterns between outlines found that IOL1 differed from other outlines. While shapes in two Anopheles of all cells were different between species, there was statistical significance based on Mahalanobis distances (p < 0.05). Almost all pairwise Mahalanobis distances between Culex species of IOL1, IOL2 and EOL established statistical differences, except for pairs of Cx. visnui and Cx. whitmorei via IOL2 analysis.

Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Outline-based geometric morphometric analysis to identify two Anopheles and three Culex mosquitoes in Thailand

2019

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“…Geometric morphometric (GM) techniques are a modern approach recognized as useful for the identification of species in many insects (Dujardin 2011;Chaiphongpachara 2018). Currently, many types of insects that have obstacles in identification by a morphological method in class Insecta has been confirmed such that the GM approach can help solve this problem, such as three members of the mosquito species of the Maculatus group (Anopheles maculatus, An.…”

Section: Introductionmentioning

confidence: 99%

Geometric morphometry of pupae to identify four medically important flies (Order: Diptera) in Thailand

Tubsamut

2019

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Abstract. Chaiphongpachara T, Tubsamut P. 2019. Geometric morphometry of pupae to identify four medically important flies (Order: Diptera) in Thailand. Biodiversitas 20: 1504-1509. In this study, we evaluated an outline-based geometric morphometric (GM) approach for species identification from pupae of four common flies medically important in Thailand, Chrysomya megacephala, Lucilia cuprina, Musca domestica, and Boettcherisca nathani. For size estimation, mean perimeter length was used. For shape analysis, Elliptic Fourier Analysis was performed to produce the contour shape variables, which was calculated as Normalised Elliptic Fourier coefficients. Then, principal component analysis was performed on the Normalized Fourier coefficients for discriminant analysis, and used to estimate pupal shape variation among the species. The difference in size and shape between the fly species was analyzed using a non-parametric test based on 1000 permutations after Bonferroni correction for the significance level (p < 0.05). In the size analysis, the mean perimeter length for pupae of B. nathani was the largest (20.35 mm) followed by C. megacephala (14.73 mm), while that for M. domestica was the smallest (11.82 mm). The size differences were statistically significant between all species (p < 0.05). The contour shapes of all pupae were significantly different among all species. The results of this study can be used as a basis for the future application of GM to identify other types of flies via their pupae.

“…The advantage of GM is that it is a cheap method which does not require much equipment, is easy to use and is rapid (Rohlf 2002). Currently, both GM methods have been applied to the study of entomology, including mosquito (Chaiphongpachara 2018;, beetle (Lamb et al 2013), blow-fly (Sontigun et al 2017), spider (Fernández and Marugán 2017), pupae of flies (Chaiphongpachara and Laojun 2019), and bee (De Souza et al 2015). Although it is an effective alternative tool, not all organisms can be identified by this technique, so it is necessary to study the feasibility of applying it to each organism (Ruangsittichai et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Geometric morphometrics as a tool for three species identification of the firefly (Coleoptera: Lampyridae) in Thailand

Sumruayphol

2019

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Abstract. Chaiphongpachara T, Sumruayphol S. 2019. Geometric morphometrics as a tool for three species identification of the firefly (Coleoptera: Lampyridae) in Thailand. Biodiversitas 20: 2388-2395. Firefly is an insect belonging to the Lampyridae family that is important to the ecosystem, generates income from tourism in the area and act as a biological control for snail, an intermediate hosts of trematode parasites. Some types of the firefly, it is difficult to distinguish the species using standard methods because of similarities in morphology while the external characteristics of specimens are damaged during collection, presenting an obstacle to species identification. This study used geometric morphometrics (GM) for identification of firefly species. Samples collection was conducted in the rainy season from August to October 2015 in three districts of Samut Songkham province, Thailand. A total of 200 and 157 fireflies from 3 genera and four species, including Luciola aquatilis Thancharoen, Pteroptyx valida Olivier, Pteroptyx malaccae Gorham and Pyrocoelia praetexta Olivier were used for landmark-based and outline-based GM analysis, respectively. The results showed that both types of GM analysis produced similar results, size variation between two firefly pairs was not statistically significant, including female L. aquatilis with male P. praetexta, and female P. valida with male P. valida. Both landmark-based and outline-based GM methods can distinguish the shape for each type of firefly with high accuracy, especially the outline-based GM method. This result was supported by reclassification scores. According to our findings, the GM can be used to separate species of firefly with high efficiency. Therefore, this GM method represents one way of overcoming difficulties with firefly identification and can support future studies of fireflies.