Comparison of Two Different Morphological Methods to Study the Pronotum of Cimicidae: Bed Bugs, Bat Bugs, and Swallow Bugs

Linear Morphometry of Male Genitalia Distinguishes the Ant Genera Monomorium and Syllophopsis (Hymenoptera: Formicidae) in Madagascar

Morphometric analyses of male genitalia are routinely used to distinguish genera and species in beetles, butterflies, and flies, but are rarely used in ants, where most morphometric analyses focus on the external morphology of the worker caste. In this work, we performed linear morphometric analysis of the male genitalia to distinguish Monomorium and Syllophopsis in Madagascar. For 80 specimens, we measured 10 morphometric characters, especially on the paramere, volsella, and penisvalvae. Three datasets were made from linear measurements: mean (raw data), the ratios of characters (ratio data), and the Removal of Allometric Variance (RAV data). The following quantitative methods were applied to these datasets: hierarchical clustering (Ward's method), unconstrained ordination methods including Principal Component Analysis (PCA), Non-Metric Multidimensional Scaling analyses (NMDS), Linear Discriminant Analysis (LDA), and Conditional Inference Trees (CITs). The results from statistical analysis show that the ratios proved to be the most effective approach for genus-level differentiation. However, the RAV method exhibited overlap between the genera. Meanwhile, the raw data facilitated more nuanced distinctions at the species level compared with the ratios and RAV approaches. The CITs revealed that the ratios of denticle length of the valviceps (SeL) to the paramere height (PaH) effectively distinguished between genera and identified key variables for species-level differentiation. Overall, this study shows that linear morphometric analysis of male genitalia is a useful data source for taxonomic delimitation.

Lateralized Movements during the Mating Behavior, Which Are Associated with Sex and Sexual Experience, Increase the Mating Success in Alphitobius diaperinus (Coleoptera: Tenebrionidae)

In the present study, we explored the effects of displacement directionality in mating behavior (i.e., lateralized and non-lateralized movements) on mating success (i.e., copulation occurs) and efficiency (i.e., time length at which copulation is achieved), and its association with sex and sexual experience in A. diaperinus. To do so, we carried out mating experiments and recorded the behavior of the mating pair during the whole mating sequence (i.e., precopulatory and copulatory phases). During the precopulatory phase, independently of sex and sexual experience, all beetles performed non-lateralized (i.e., backside or frontside) approaches; however, only sexually experienced beetles showed lateralized approaches (i.e., right-side and left-side). Notably, experienced males exhibited greater mating success than virgin males. After the approach, both virgin and experienced males displayed lateralized and non-lateralized mounts on the females with distinct mating success. Regardless of their sexual experience, 100% of successful mating attempts were achieved when males mounted from the females' right side. Furthermore, the development of lateralized approaches and mounts reduces the time of mating sequence span compared with non-lateralized behaviors. We highlight the importance of lateralization in mating behavior and sexual experience to achieve higher mating success, addressing a potential learning ability of beetles based on experience.

Wing geometric morphometrics to distinguish and identify Haematobosca flies (Diptera: Muscidae) from Thailand

The hematophagous flies of the genus Haematobosca Bezzi, 1907 (Diptera: Muscidae) are important ectoparasites in domestic animals and wildlife. Two species of this genus have been recorded in Thailand, viz., Haematobosca sanguinolenta (Austen, 1909) and Haematobosca aberrans (Pont, Duvallet & Changbunjong, 2020). They have a similar morphology and coexist in the same habitat. The correct species identification of these flies is extremely important for understanding disease epidemiology and developing effective control measures. Geometric morphometrics (GM) has been confirmed to be a useful tool for differentiating and identifying morphologically similar insect species. Therefore, GM was used to distinguish and identify H. sanguinolenta and H. aberrans in Thailand. Adult flies of both sexes were collected using Nzi traps, morphologically identified, and analyzed by landmark-based GM of the wing. Results showed that GM was highly effective in distinguishing the two Haematobosca species based on their wing shape, with an overall accuracy score of 99.3%. We also revealed that our study material could be used as reference data to identify new field specimens collected from other geographic locations. We propose that wing GM can be used as a supplement to conventional morphology identification, particularly for Haematobosca specimen that has been damaged or has lost its diagnostic characteristics due to specimen collection and processing in the field.