Colour polymorphism of cotton bollworm larvae as a function of the type of host plant providing its development

A well-known insect phenomenon is colour polymorphism, from which the species hopes to gain some ecological advantage. Herbivores adapt to the colours of their environment to reduce their chances of becoming prey, while predators use camouflage colours to succeed in hiding from prey. The larvae of the cosmopolitan, highly invasive cotton bollworm (Helicoverpa armigera Hbn., Lep.: Noctuidae) also benefit from this morphological polymorphism. Their fully-developed larvae can take on various colours when feeding on foliage. Our study aimed to determine the host plant-related colour adaptation of H. armigera larvae collected from different plant organs using different spectral analysis methods. Our studies, based on colour analysis of photographic images, showed that the colour of fully-developed larvae of the species is highly correlated with the colour of the damaged nutrient plant. The dominant colours of the larvae show a high similarity with the colours of the consumed host plant parts. The RGB-based analysis confirmed that larval colours are clustered according to the host plant’s organs and are mainly located in the yellow and green regions of the visible light spectrum. All these results confirm the extraordinary adaptive capabilities of this invasive species, which, among other things, verify its worldwide distribution

Automatic method for determining the number of lumbar and thoracic vertebrae in rabbits using Computer Tomography images

There are several studies dealing with the phenotypic variance of the vertebral number in the spinal column of rabbits. According to the literature the number of thoracic and lumbar vertebrae varies between 11-13 and 6-8, respectively. The length of the m. longissimus dorsi (MLD) - a valuable meat part of rabbits - is determined by the length of the vertebral column therefore the number of vertebrae may have economic importance in breeding. The aim of this study was to create an automatic counter using computed tomography (CT) images. In the first step, a skeleton binary mask was created using the radiodensity range between 120 and 3071 HU, then the lumbar and thoracic regions were processed by two different methods. The lumbar part was evaluated based on the frequency of the bone voxels along the axial plane. The number of thoracic vertebrae was determined from the number of ribs. The left and right ribs were processed separately. The developed method was tested on CT examination of 40 Hycole rabbits compared to manual evaluation. The results of the automatic algorithm had few errors: in one case in the lumbar region (2.5%) and in 3 cases in the thoracic region (5%). The automated evaluation process takes a few seconds per individual and then the program visualizes the results on a graph. The incorrectly evaluated rabbits are recognizable on graphs and they can be easily corrected with a minimal time investmen