Is Hive Abandonment an Altruistic Behavior in Honey Bees to Prevent the Spread of Apocephalus borealis?
A research proposal by Mary May DeBettignies
Honey bee populations are being decimated by numerous pathogens and parasites. One of the factors involved with the rapid decline of bee populations is the phorid parasite, Apocephalus borealis. A. borealis infects honey bees by ovipositing into the abdomen. The infected bees will then display erratic behavior such as attraction to light posts, loss of equilibrium, inability to fly, and refusal to sting (Arce and Pedraza, 2012). The bees die shortly after, and approximately seven days later, an average of five larvae emerge from the junction of the head and the thorax. The larvae mature in about 28 days and go on to infect new hosts. (Core et al., 2012)
In recent years, many hives are exhibiting Colony Collapse Disorder (CCD), a syndrome characterized by worker bees abandoning the hive. Little is understood about hive abandonment behavior because there are many variables involved with this phenomenon. The two main proposed theories to explain hive abandonment behavior are altruism and disturbances in the circadian rhythms of the bees. Bees display behaviors that benefit others more than themselves because they are so closely related to their hive mates. Bees will forgo behaviors that increase their own personal fitness in order to increase their inclusive fitness. In this case the bees are not acting in their own interest, but in the interest of their genes (Dingfelder, 2006). This theory predicts that an infected bee will leave its hive in order to prevent the spread of infection to its family. We will test how infected and uninfected bees interact with other bees.
We expect to find that infected bees attempt to isolate themselves from their kin. These results would show that hive abandonment behavior, in the case of infection by A. borealis, is an altruistic behavior in order to save the colony. This knowledge would help us to better understand CCD and aid further research on how to save the honey bee.
Infected honey bees will isolate themselves from uninfected hive mates.
1. Do infected bees separate themselves from other hive members to avoid infecting family?
2. Do infected bees isolate themselves from uninfected bees of other hives?
We will select three hives and remove fifteen bees from each hive. We will then infect two bees from each hive and mark them with a red paint pen. Bees cannot differentiate between red and black, so we will not need a control group for the paint (Burns, 2012). We will then separate the bees into various combinations of infected and uninfected groupings and place the groups into 4 x 2 x 2 foot glass containers. We will then observe their interactions under laboratory conditions to determine whether infected bees isolate themselves from uninfected hive mates. We will have a control group for each of the three hives (Figure 2). The control groups will be comprised of five uninfected bees from hives one, two, and then three. This will gives us data to compare with our experimental group to show whether uninfected bees isolate themselves from each other also.
a. Question 1: To determine whether infected bees separate themselves from other hive members to avoid infecting family we will place one marked, infected bee with four uninfected bees from the same hive, and then observe their interactions. We will replicate this for all three hives (Figure 1). We expect that the infected bee will avoid its uninfected hive mates. This would suggest the infected bee is trying to protect his kin from infection in order to increase his inclusive fitness.
B. Question 2: To determine whether bees will isolate themselves from uninfected bees of other hives we will place one infected bee from hive #1 with four uninfected bees from hive #2, one infected bee from hive #2 with four uninfected bees from hive #3, and one infected bee from hive #3 with four uninfected bees from hive #1 (Figure 3). The infected bees will be marked with a red paint pen for identification. We will then observe their interactions. We expect that the bees will not avoid each other. Such results will show that isolation is an altruistic behavior to increase inclusive fitness and so this behavior will not be shown towards bees from other hives. This would suggest that bees infected with A. borealis altruistically abandon their hives to protect their hive mates.
Expected Outcomes and Potential Problems
We expect that bees infected with A. borealis will isolate themselves from uninfected bees from the same hive. We also expect that infected bees will not avoid uninfected bees from other hives. Because bees show altruistic behaviors towards bees belonging to the same hive, such results would suggest that hive abandonment is an altruistic behavior to prevent the spread of A. borealis to hive mates. Lastly, in our control group, we expect that uninfected bees from the same hive will not avoid each other.
One problem that could arise in our experiment would be a lack definite evidence of bees avoiding or not avoiding each other. If bees do not act in a natural way when taken out of their hives and into a laboratory setting, this will also skew our data.
This study will determine whether hive abandonment is an altruistic behavior to prevent the spread of A. borealis. The results will inform biologists about why CCD occurs and how A. borealis affects honey bees. Further understanding of why colonies collapse will help us to prevent loss of bee populations.
Arce, A.P. and Pedraza, R. (2012). Evaluation of Phorid Fly (Apocephalus borealis) Parasitism of Feral Honey Bee (Apis mellifera) Colonies in South Orange County.
Burns, David. “Welcome To Basic Beekeeping Lesson 34 Marking The Queen.”Beekeeping: Marking The Queen. Long Lane Honey Bee Farms, n.d. Web. 10 Dec. 2012.
Core A, Runckel C, Ivers J, Quock C, Siapno T, et al. (2012) A New Threat to Honey Bees, the Parasitic Phorid Fly Apocephalus borealis.PLoS ONE 7(1): e29639. doi:10.1371/journal.pone.0029639
Dingfelder, Sadie F. (2012). Altruism: An Accident of Nature? Monitor on Psychology 37.11 (2006): 44.