15th Beekeepers’ Network Conference and Techno-fora July 2009

On Training Trigona biroi : Behavioral Complexity and Apparent Patterns

Jomar F. Rabajante1 and Alejandro C. Fajardo, Jr.2 1Institute of Mathematical Sciences and Physics, University of the Philippines Los

Baños2Institute of Biological Sciences, University of the Philippines Los Baños

ABSTRACT

Interacting individuals with collective nonlinear behavior compose a complex system. Experiments conducted at the University of the Philippines Los Baños (UPLB) on May 4 to June 5, 2009 show that the learning behaviors of stingless bee (Trigona biroi) colonies exhibit nonlinearity and complexity. Training the stingless bees to feed on unfamiliar food type requires definite environmental factors suited for learning. Since bees are sensitive to many environmental factors, a balanced level of the preferred factors is necessary throughout their food search. During training, an adequate amount of sunlight should be present in a semi-enclosed space where the colonies can be initially located. The semi-enclosed space should lead the bees to the well-located sample food source without limiting them to fly freely.

An observable trend exists to test whether scouts are starting to communicate the location and characteristics of the newly found food. If learning is successful, the number of attracted foragers follows an increasing curve fit through time. The geometry of the footprints left by the bees during foraging indicates their food preferences. As an application, training the stingless bees to feed on nectars can help in the development of pollination, but sufficient effort is crucial in determining the best balance of factors needed to attract the bees.

Keywords: stingless bees, Trigona biroi, complexity, nonlinearity, learning behavior

INTRODUCTION

A complex system is composed of interacting, possibly heterogeneous, individuals. Usually, such system is dynamic and has sophisticated structures, which make its designs hard to comprehend. However, it is possible that the heterogeneity of the members of the system can build up to have a homogenous collective behavior. The collective behavior may tend to work-out for stability, and thus, the system may have recognizable behavioral patterns. The behavioral patterns may appear in the systems’ “attractor” or “edge-of-chaos”.

A complex system, such as a bee colony or a set of bee colonies (Beekman & Wilkinson, 2004), is said to be nonlinear. This means that the

15th Beekeepers’ Network Conference and Techno-fora July 2009

occurrence of a certain event may not be linearly related to the occurrence of another event. Bees may have different behaviors toward the same set of events.

A complex system is open, i.e. it is subject not only to the internal environment but also to the external environment. Bee colonies are open systems, and they are affected by many environmental factors. One of these factors is weather. Bee behavior is affected by changes in the climate. However, bee colonies are adaptable systems. Given an appropriate environmental conditions, bees can adapt to changes. Adaptability is a characteristic of most complex systems.

A complex system has feedback loops and memory. Bees in a colony communicate to each other to have feedback loops. Information flow is very important during their foraging activities. The decisions of most foragers rely on the information sent by the scouts and by other foragers. Moreover, bees have memory. The location of food sources are remembered by the foragers. Bees also learn by association, e.g. association of food availability to the color and shape of visited feeders (Scheiner et. al, 2004).

Training bee colonies to feed on unfamiliar food type is one of the major concerns of researchers, beekeepers and agriculturists. If researchers need to study the foraging behavior of bees, sometimes the researchers need to introduce a new food type to the colony. If the weather is not suitable for the bees to search for food in an open field, beekeepers usually give the colonies artificial food such as sucrose. Agriculturists use bees for pollination of certain crops which may not be familiar to the bees. Hence, it is a necessity to train the bees to learn the newly introduced food types prior to doing large activities concerning bee foraging behavior.

The objectives of this study are:• To determine the complex behaviors of Trigona biroi;• To determine a near-optimal way of training the bees to learn a new

food-type; and• To determine the behavioral patterns of Trigona biroi during Scouting,

Recruitment and Foraging.

EXPERIMENT PROPER

There were four related experimental designs and two independent experimental designs. The same set of colonies was used in the related experiments, while different colonies were used for the independent experiments. Independent experiments were done to verify the results of the related experiments.

15th Beekeepers’ Network Conference and Techno-fora July 2009

FIGURE 1: Design of the Related Experiment 1 (Open Field)

For the related experiment 1, three colonies were placed in an open field. Feeders were placed at a distance 1m from and with the same level of height as the beehive opening of each colony. 40%, 50% and 60% sucrose concentrations with a drop of vanilla were placed in each feeder. The setup was conducted for three consecutive sunny days, starting 6AM to 4PM.

The experiment showed that an open field is not a good enabling environment for training. For the duration of the experiment, only one bee attempted to visit the feeders. The intuitive hypothesis for this situation is that an open field provides the bees plenty of food choices to choose from, and thus, this makes training inappropriate.

FIGURE 2: Design of the Related Experiment 2 (closed room, no direct sunlight)

For the related experiment 2, three colonies were placed in a closed room where there is no direct sunlight coming through the windows. Feeders were placed at a distance 1m from and with the same level of height as the beehive opening of each colony. 40%, 50% and 60% sucrose concentrations

15th Beekeepers’ Network Conference and Techno-fora July 2009

with a drop of vanilla were placed in each feeder. The setup was conducted for three consecutive sunny days, starting 6AM to 4PM.

The experiment showed that a closed room (with no direct sunlight) is not a good enabling environment for training. For the duration of the experiment, no bee attempted to visit the feeders. In fact, bees tend not to come out of their beehive. The intuitive hypothesis for this situation is that sunlight is one of the important enabling factors for training.

FIGURE 3: Design of the Related Experiment 3 (closed room, with direct sunlight)

For the related experiment 3, three colonies were placed in a closed room with direct sunlight coming through the windows. Feeders were placed at a distance 1m from and with the same level of height as the beehive opening of each colony. 40%, 50% and 60% sucrose concentrations with a drop of vanilla were placed in each feeder. The setup was conducted for three consecutive sunny days, starting 6AM to 4PM.

FIGURE 4: Swarm of bees in the windows (Related Experiment 3)

15th Beekeepers’ Network Conference and Techno-fora July 2009

Related Experiment 3 showed that a closed room (with direct sunlight) is not a good enabling environment for training. For the duration of the experiment, only five bees attempted to visit the feeders. However, compared to the closed room with no sunlight, now bees tend to come out of their beehives. The problem is bees did not search for food; instead the bees flew to the windows pursuing to come out of the room. The intuitive hypothesis for this situation is that sunlight affects the activeness of the bees; however, bees should not be controlled in a closed room in order for them to fly freely.

FIGURE 5: Design of the Related Experiment 4 (opened windows, with direct sunlight)

For the related experiment 4, three colonies were placed in a room with opened windows and where there is direct sunlight coming through the windows. Feeders were placed at a distance 1m from and with the same level of height as the beehive opening of each colony. 40%, 50% and 60% sucrose concentrations with a drop of vanilla were placed in each feeder. The setup was conducted for three consecutive sunny days, starting 6AM to 4PM.

The experiment showed that a room (with opened windows and direct sunlight) is a good enabling environment for training. Related experiment 4 is a result of an accident happened while doing Related Experiment 3. Accidentally, one of the windows was opened and after 4 minutes, bees started to forage in the prepared feeders. To repeat Related Experiment 4, Independent Experiment 1 (with three replicates) was carried out and the result was successful. The intuitive hypothesis in the Related Experiment 3 is now verified, i.e. sunlight and a not-so-controlled condition are some of the enabling factors for training the bees.

15th Beekeepers’ Network Conference and Techno-fora July 2009

FIGURE 6: Design of the Independent Experiment 2 (Semi-enclosed Area)

For the Independent Experiment 2, a colony was placed in a semi-open field, with a guiding wall in one side. Feeders were placed at a distance 1m from and with the same level of height as the beehive opening of the colony. 40%, 50% and 60% sucrose concentrations with a drop of vanilla were placed in each feeder. The setup was conducted for three consecutive sunny days, starting 6AM to 4PM. There were five replicates for this experiment.

The researchers thought that it is not the room that influenced the success of Related Experiment 3 and Independent Experiment 1, but the idea of having a guided environment. The bees still need to feel the freedom of flying, in a natural environment-like setting, while guiding them to learn. The result of Independent Experiment 2 is more notable than Related Experiment 3 and Independent Experiment 1. There are more bees that foraged in the feeders set up during Independent Experiment 2. Using Two-Sample Kolmogorov-Smirnov Test (Nonparametric), at 95% confidence level, results of Independent Experiment 1 and 2 have significant difference.

The result of the experiments can be used for future researchers regarding the effect of bee pollination in a greenhouse garden. There are many factors to consider in training the bees, some of them are the food itself (e.g. sucrose concentration), sunlight and light direction, space of the food location, and weather.

APPARENT PATTERNS

An observable trend exists to test whether scouts are starting to communicate the location and characteristics of the newly found food. If

15th Beekeepers’ Network Conference and Techno-fora July 2009

learning is successful, the number of attracted foragers follows an increasing curve fit through time. 

FIGURE 7: Behavior of Successful Scouting

Successful scouting can be predicted through the visiting patterns of the scouts. Given a feeder distance of 1m from the beehive, a successful scout will initially inspect the newly discovered feeder for more than 1 minute duration. The successful scout will then subsequently visit the feeder for approximately 1 hour. The duration of the subsequent inspections is decreasing until it level-off as shown in Figure 7.

FIGURE 8: Behavior of Successful Foraging

Successful scouting can still result in a failure of communication between the scout and forager. Successful communication results to successful foraging, and successful foraging can be seen in the growth of number of visiting bees.

Inside a roomSemi-open field

15th Beekeepers’ Network Conference and Techno-fora July 2009

FIGURE 9: Visiting Trigona biroi

Another apparent pattern that can be seen during the foraging activity of Trigona biroi is the geometry of their footprints. Trigona species leave olfactory cues in every visited feeder (Villa & Weiss, 1990; Boogert et al., 2006). However, existing studies only focus on the chemistry of this cues or footprints. In day to day beekeeping, chemical analysis of the footprints is impractical; hence, analysis of the physical properties, such geometrical characteristics, of the footprints is preferable.

FIGURE 9: Footprints of Trigona biroi

Using ImageJ, the fractal dimension of the footprints was analyzed. The result of the box counting analysis showed that the footprints are indeed fractal. The footprints of Trigona biroi can now be added in the list of fractals

15th Beekeepers’ Network Conference and Techno-fora July 2009

in nature. The fractal dimension of the footprint sample, shown in Figure 9, is 1.7393.

FIGURE 10: Analysis of the Footprints of Trigona biroi

References:

Beekman, M., & Wilkinson, I.F. (2004). What can social insects teach us about marketing. Australia New Zealand Marketing Academy Annual Conference, Wellington, December, 2004.

Scheiner, R., Page, R. E., & Erber, J. (2004). Sucrose responsiveness and behavioral plasticity in honeybees (Apis mellifera). Apidologie, 35, 133-142.

Villa, J. D., & Weiss, M. R. (1990). Observations on the use of visual and olfactory cues by Trigona spp foragers. Apidologie, 21, 541-545.

Boogert, N. J., Hofstede, F. E., & Monge, I. A. (2006). The use of food source scent marks by the stingless bee Trigona corvina (Hymenoptera: Apidae): the importance of the depositor.s identity. Apidologie, 37, 366-375.

Rasband, W. ImajeJ 1.42q. National Institutes of Health, USA.

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