GLMM applied on honeybee pollination data

IENO E; MAGGI M; DE PIANO F; DE FEUDIS L; EGUARAS E; HILBE J; ZUUR A

A beginner's guide to GLM and GLMM with R: A frequentist and Bayesian perspective for ecologists

Highland Statstics

Año: 2013;

In the process of collecting nectar for honey production, honeybees are valuable pollinators of agricultural crops producing seeds and fruits. Among those crops, the kiwifruit (Actinidia spp.) has received special attention, as it can be grown in most temperate climates and produces large quantities of fruits per hectare. Kiwifruit of the species Actinidia chilensis is produced across Argentina, especially in the southwest of Buenos Aires Province. While the role of the honeybee as a pollinator of Actinidia and of wild flora has been studied elsewhere, no baseline data exist for the extensive area of Buenos Aires Province. Individual kiwifruit vines produce either male or female flowers, which means that plants are not self-pollinating, and pollen is brought to female flowers by wind and/or insects. It has been documented that the production of kiwifruit positively correlates with the number of honeybee hives placed in kiwifruit orchards (Free, 1993). Thus, growers distribute honeybee hives throughout plantations to facilitate the pollination process. Kiwifruit blossoms produce no nectar. In addition, the coincident flowering of other nearby flora may attract pollinators away from kiwi flowers. This is the case with respect to dandelion (Taraxacum officinale), which is abundant in the south of Buenos Aires Province. Therefore supplemental feeding of colonies with sugar syrup has been widely recommended to enhance the attractiveness of kiwi flowers to honeybees. To evaluate whether supplemental feeding increases the amount of kiwi and dandelion pollen foraged by honeybees, colonies were provided with either protein or sugar syrup during 4 days. Five hives were used for each experimental treatment, with a further five unsupplemented hives used as controls. Pollen traps were place at the entrance of the hives over four consecutive days at kiwi peak bloom. Every morning the number of pollen grains in the traps were counted and removed from the traps.