The Coffee Berry Borer, Hypothenemus hampei, is one of the most important pests of coffee. This pest increases the cost of your cup of coffee. Scientists have been studying the biology of the The Coffee Berry Borer to search for methods of control. The females bore a hole in the top of the developing berry and lay eggs inside the berry. Traditional methods of insect control such as insecticide sprays do not work for this pest because little spray penetrates inside the berry. The development cycle takes place within a berry: egg, larva, pupa, adult.
Coffee Berry Borers mate within a berry. Only the female leaves. The male never leaves the berry. The females need good vision to navigate in the environment. The males have a reduced need for vision and their eyes are smaller than females. Females have compound eyes with 122 to 136 facets. Male compound eyes have only 12 to 27 facets. A group of scientists* tested the optomotor response of female and male beetles. Females responded to the visual stimulus: males did not.
Organs that are not needed are sometimes lost in species, especially if there is a cost to producing the organ. Male Coffee Berry Borers produce an eye of diminished complexity. At this time we do not know how much the male saves in energy and biomass; Neither do we understand where that savings is redirected. The male retains a diminished visual capacity. It is not clear how that capacity is used. Although it is a pest, Coffee Berry Borer possesses many unusual features for further study.
*Vega FE, Simpkins A, Bauchan G, Infante F, Kramer M, et al. (2014) On the Eyes of Male Coffee Berry Borers as Rudimentary Organs. PLoS ONE 9(1): e85860.
You might be interested in this free, open-access article from the Journal of Integrated Pest Management on how to use IPM to manage this insect: http://entsoc.org/press-releases/ipm-program-coffee-berry-borer
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