Smith, B. P. | bioRxiv Science

bioRxiv2021

Species boundaries among extremely diverse and sexually dimorphic Arrenurus water mites (Acariformes: Hydrachnidiae: Arrenuridae)

Arrenurus (Arrenuridae) is the most species-rich genus of mites with about 950 named species that inhabit standing, and to a lesser extent, running water habitats around the world. To date, distinguishing species of Arrenurus has been based on male reproductive morphology. Here, we use morphological and molecular approaches to examine species boundaries among 42 named species of Arrenurus, including four named species that have colour variants (red and green A. americanus, and red and blue A. intermedius, A. manubriator and A. apetiolatus), and two unnamed morphospecies. In this study, we examine male genital structures with the use of SEM techniques, and apply mitochondrial (COI barcode region) and nuclear (28S rRNA) gene fragments to test whether male morphology reflects species boundaries in Arrenurus assessed by molecular analyses. Our results reveal that male reproductive morphology parallels species boundaries as judged by molecular data. We discuss the cases of genetically poorly diversified, yet morphologically clearly defined named species. Moreover, we show that based on the species we examined, colour morphs within otherwise morphologically similar specimens represent within-species variation and, in the absence of other diagnostic traits, colour itself can be misleading in distinguishing species. Our outcomes on molecular taxonomy of Arrenurus provide a background for testing hypotheses about speciation rate in water mites.

zoology↗

bioRxiv2019

Investigating risk factors that predict a dogs fear during veterinary visits

Attending the veterinary clinic is an integral part of the physical welfare of every companion dog. However, some dogs experience their veterinary visits negatively, which poses a risk of injury to the veterinary staff, their guardian (owner) and themselves during veterinary examinations. It may also influence the regularity of non-urgent veterinary appointments. To date there has been conflicting data on the proportion of dogs that are fearful during their veterinary visits. In this study, we explored the risk factors associated with fear during veterinary examination and in novel situations (including first time at the veterinary clinic) from 26,555 responses in the Canine Behavioral Assessment and Research Questionnaire database. According to their guardians, over half (55%) of companion dogs displayed some form of fearful behaviour (mild-extreme) when examined by a veterinarian, while 14% of dogs exhibited severe or extreme fear. A similar trend was observed with dogs responding fearfully in unfamiliar situations, including the dogs first time at the veterinary clinic. Chi-squared tests showed every bivariate relationship was significant (p < 0.05). The most important predictors of fear in a veterinary examination were, in order: the dogs breed group (27.1%), their history of roles or activities (16.7%), where they were sourced (15.2%), their weight (12%), the age of other dogs in the household (9.5%) and dog owner experience (6.3%). However, these risk factors accumulate to explain a total of 7% of variance of fear observed during veterinary examination. Results demonstrate that fear of veterinary visits is common in dogs, but that other factors (including the environment or human-animal interactions) are likely to contribute more to prevalence and severity of this problem than the demographic factors measured here. Finally, we highlight opportunities for future research aimed at facilitating less stressful veterinary visits for dogs and their guardians.

animal behavior and cognition↗