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Browsing by Subject "ecology"

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  • Species misidentification in ecological studies : incidence and importance from the ecologists’ point of view 
    Wang, Shengyu (2021)
    Natural scientists study a wide variety of species, but whether they have identified all studied samples correctly to species is rarely evaluated. Species misidentification in empirical research can cause significant losses of money, information, and time, and contribute to false results. Thus, I study the abundance of species misidentification and ecologists’ perceptions of such mistakes through a web survey targeting researchers from scientific institutes around the globe (including universities, research societies and museums) who completed their doctoral degree in any ecology-related field of science. I received 117 responses with either work or educational background from 30 countries. I found that species misidentification widely existed in respondents’ research: almost 70% of the respondents noticed species misidentification in their own research, while the estimated proportion of existing studies with species misidentification was 34% (95% CI: 28% - 40%). Although misidentification was mainly found during specimen collection, specimen handling and data analysis, misidentifications in reporting stages (writing, revision and after publishing) could persist until publication. Moreover, according to respondents, reviewers seldom comment about species identification methods or their accuracy, which may affect respondents’ (both leading and not leading a research team) low reporting frequency about the possibility of misidentification. Expert checking, training students, and DNA barcoding are the most prevalent approaches to ensure identification accuracy among respondents. My results imply that species misidentification might be widespread in existing ecological research. Although the problem of species misidentification is widely recognized, such an issue seldom be appropriately handled by respondents. To increase the accuracy of species identification and maintain academic integrity, I suggest that researchers need to focus more on the study species (e.g., sampling process, identification method, and accuracy) when writing and reviewing papers. Furthermore, I appeal for guidelines about reporting species identification methods and their accuracy in papers, as well as research on education about identification skills in universities, as these two topics may constrain the precision of species identification.
  • The effects of diet on squamate brain morphology 
    Aalto, Ida-Maria (2021)
    The general structure of the vertebrate brain is highly conserved. However, a large amount of variation exists in brain size and shape, both regarding the whole brain and its subdivisions. This variation is caused by selection acting on species’ behavioural traits and shaping the evolution of the brain in the same process. It is known that one of the factors affecting vertebrate brain morphology is ecology, including habitat complexity, activity patterns and diet. The effects of diet on brain size have been studied in primates, bats and small mammals, where frugivory in primates and bats and insectivory in small mammals, are linked to larger brains. The effect of diet on brain morphology has not been studied in squamate reptiles (lizards and snakes) and the ecological factors behind size and shape variation are largely unknown in squamates compared to other vertebrates. Squamates show large diversity in diet preference as well as feeding behaviour in general, which makes them a suitable model organism to study brain evolution. Further, squamates have highly developed nasal chemical senses that are important for feeding behaviour. These factors in mind, it would be expected that diet has an effect on squamate brain morphology, and especially the brain regions important for feeding behaviour, such as the olfactory bulbs in the forebrain. To study the effects of diet on squamate brain size and shape, the brains of 51 squamate species were micro-CT scanned and 3D-brain surfaces were generated for each species. The species were categorized into four diet groups: carnivorous, herbivorous, omnivorous and insectivorous. To analyse shape and size change across species and diet groups, 73 landmarks were placed on each 3D-brain surface, covering all brain regions: olfactory bulbs, cerebral hemispheres, telencephalon, diencephalon, midbrain, cerebellum and hindbrain. The results from this study show that diet affects significantly the shape of the whole squamate brain, as well as the size of the telencephalon. Telencephalon size differed significantly between the herbivorous and carnivorous groups. Diet had no significant effect on the other brain subdivisions studied here, including the olfactory bulbs. Diet is a large part of a species’ ecology and it is very complex behaviour involving several senses and brain regions, which could explain the results obtained from this study. The results from this study are preliminary, but they indicate that diet could be one of the factors affecting brain morphology in squamates. In the future, including other factors of feeding behaviour than food choice and analysing the effects of diet on a deeper level, such as including brain regions within the brain and analysing cellular organization, could shed some new light on how diet affects squamate brain morphology.

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