|dc.contributor.author||Bowie Mike, H.||en
|dc.description.abstract||The aim of this study was to investigate the usefulness of image analysis for studying
mite behaviour. Image analysis was used to convert video recordings of mites' locomotory
behaviour into a series of x,y coordinates that, when joined, closely resemble the paths
of mites. The coordinates were also used to calculate walking speed, direction of travel,
turning frequency, turn bias and tortuosity. Two experimental arenas were developed
and used to study the movement of three mite species: 1) a leaf disc arena for two-spotted
spider mite, Tetranychus urticae Koch and European red mite, Panonychus ulmi
(Koch); and 2), a cover-slip/tack-trap arena for Typhlodromus pyri Scheuten.
Two-spotted spider mite exhibited a change in locomotory behaviour through a 48 minute
period. Mites exhibited a significant decline in distance travelled, whereas the mean
stationary time (per four minute interval) more than doubled, and the duration of
stationary events increased steadily over the same period.
A reduction in sampling frequency of mite coordinates from one per second to one every
two seconds and every four seconds produced a 5% and 12% 'loss' in path length
Sample period length was shown to greatly influence the results produced for some of the
mean parameters calculated, however, a reduction in sample length from 3000 to 1500
coordinates was not considered to cause a major loss in information. The influence of
the inherent mite movement could not be ignored and made it difficult to make decisions
on the 'best' sample length to use.
Some strong correlations were found between parameters used to analyse mite
locomotory behaviour. In particular, arithmetic mean vector length, speed, total
stationary time and total distance travelled were significantly correlated with each other.
Mean angular deviation and weighted mean vector length, which both measure the degree
of clustering around the mean heading angle, were strongly negatively correlated.
Parameters which differentiated between 'straight' and 'tortuous' mite movement were
found to be mean meander, absolute mean turn and fractal dimensions. Mean meander
was thought to be the most 'powerful', while coefficient of a straight line, a commonly
used parameter for measuring tortuosity, did not significantly differentiate between the
two different behaviours.
Frequency distributions of turns and standard deviations of the three mite species were
very similar. All three species had a slight bias to turning right (clockwise) rather than
to the left (counter-clockwise) and for each species certain angles occurred more often
than would be expected in a 'perfect' normal distribution. A similar pattern also occurred
with the frequency distribution of two-spotted spider mite heading angles, in that angles
which were expected to occur more often, did not, and vice versa.
The potential to use saturated salt solutions to control relative humidity on the arena was`
demonstrated and indicated that relative humidity is likely to have an important
influence on mite behaviour. Two-spotted spider mites appeared to move more quickly
in an attempt to escape the unfavourable, extreme (10% and 95% R.H. at 25°C) moisture
All three mite species displayed a characteristic edge-walking behaviour around the
arenas. However, when 'edge' and 'non-edge' behaviours were compared, mean meander
was the only parameter (of the parameters tested) which gave a significant difference.
Behavioural responses of European red mite and T. pyri to sub-lethal (field rate)
esfenvalerate were investigated and the results indicated that these mites did not seek
the unsprayed halves of the arenas during the first 48 minutes. However, significant
differences in most behavioural parameters to esfenvalerate residues were found with
European red mite when whole arenas were compared.
Image analysis is an extremely useful research tool for studying mite behaviour because
of its ability to measure many parameters quickly.
Careful choice of the environmental conditions, the sampling framework, and
interpretation of data is essential for meaningful results.||en
|dc.subject||two-spotted spider mite||en
|dc.subject||European red mite||en
|dc.title||Evaluation of image analysis for studing mite behaviour||en
|thesis.degree.name||Master of Applied Science||en
|dc.subject.marsden||Fields of Research::270000 Biological Sciences::270500 Zoology::270505 Entomology||en
|dc.subject.marsden||Fields of Research::280000 Information, Computing and Communication Sciences::280200 Artificial Intelligence and Signal and Image Processing::280203 Image processing||en
|lu.contributor.unit||Faculty of Agriculture and Life Sciences||en
|lu.contributor.unit||Department of Pest Management and Conservation||en
|pubs.organisational-group||/LU/Agriculture and Life Sciences||
|pubs.organisational-group||/LU/Agriculture and Life Sciences/ECOL||
|pubs.organisational-group||/LU/Research Management Office||
|pubs.organisational-group||/LU/Research Management Office/PE20||
|pubs.organisational-group||/LU/Research Management Office/QE18||