4. Measures of colony level pollination efficacy
The foraging activity of social insects is in part controlled by their colony and its requirements. Honey bees are usually managed at the colony level for pollination, i.e. colonies may be subject to particular management practices to influence their foragers’ pollinating activity.
This section covers measures for assessing the pollination efficiency of honey bees at the colony level. To determine a colony’s pollination efficiency, it is usually necessary to have an understanding of the efficiency of individual foragers at pollinating flowers from the crop to determine which assessments should be used. For example, for a crop like kiwi that only produces pollen, a measure of kiwi pollen collected by a colony will indicate the portion of foragers that are visiting the crop. Likewise for avocadoes and hybrid carrots it is only nectar foragers that are carrying out pollination activities and pollen foragers will be of less interest.
The measures of colony performance generally fit into two types. Measures can be made on returning foragers which generally relate to what flowers the foragers are visiting, whether they were foraging for pollen or nectar, and for some crops how effective they were at pollinating the crop. The second approach is to study the behaviour of foragers in the field and then attempt to determine which colony they came from. These types of studies are often carried out to assess the effect of colony level manipulations designed to increase the number of honey bees visiting a crop or their behaviour when they are visiting the crop, e.g. to measure the effect of:
- the timing of colony introductions,
- placement of colonies in the crop,
- colony strength (number of bees and amount of brood),
- organization of the colony, e.g. location of the brood or proportion of the brood that is uncapped,
- practices to change foraging behaviour, e.g. feeding pollen or syrup and using pollen traps, and
- competing floral sources.
This section covers methods for assessing
- pollen foraging
- nectar foraging
- colony foraging rates
- fraction of side working behaviour
- relationship between foragers and their hives