Project properties
Title Melanism in ladybird beetles
Group Entomology, Laboratory of
Project type thesis
Credits 36
Supervisor(s) Dr. P.W. de Jong
Examiner(s) Prof. M. Dicke
Contact info Peter.dejong@wur.nl
Begin date 2023/01/01
End date 2023/12/31
Description A number of ladybird beetles show color polymorphism, where forms are different in the extent of melanisation of their elytra. This is likely to influence their thermal regimes, and since insects are ectothermic, may also influence their activity, and, ultimately, their reproductive success. At the same time, melanin is thought to be an �expensive� compound, requiring a relatively large investment of resources. This will also influence fitness of the beetles. Experimental work can address each of these two aspects: behavioral observations to study activity differences between color forms of the ladybird Harmonia axyridis, and rearing- and measuring experiments to study costs associated with the production of melanin. The latter can also be linked to the chemical defence of these ladybird beetles: in response to attacks by natural enemies the ladybirds exude droplets of processed haemolymph, containing costly alkaloids. Trade-offs can be studied between the production of this chemical defence and production of melanin, by rearing ladybird larvae at different environmental temperatures (leading to different levels of melanisation) and giving them different reflex-bleeding regimes. For the more technically inclined student, one aspect that can be studied is also the actual thermoregulation of melanic vs. non-melanic beetles, by using infra-red thermal imaging.
Used skills life history experiments, thermal imaging, behavioural observations
Requirements For doing a BSc-thesis at Entomology, there are no requirements for specific courses.
For doing a MSc-thesis or internship at Entomology, the following requirements apply: ENT-30806 + a second ENT-course (preferably ENT-30306 or ENT-50806 or ENT-53806). As an alternative for the second ENT-course, PHP-30806 or BHE-30306 can be selected.
Note: these requirements do not apply for MBI students; MBI students should check the requirements for doing an ENT MSc-thesis or internship in the study programme of their specialisation.