Post-Doctoral Scientists

Past and Present

Ohad Afik

Post-Doctoral Scientist (BARD & Fulbright)
Since September 2008

  • B.Sc. 1998, Biology, Hebrew University of Jerusalem, Israel
  • M.Sc., 2001, Entomology, Hebrew University of Jerusalem, Rehovot, Israel
  • Ph.D., 2007, Entomology, Hebrew University of Jerusalem, Rehovot, Israel
  • Post-doctoral scientist, 2008, Evolutionary and Environmental Biology, University of Haifa, Israel

My main field of interest is the pollination behavior of the honey bee. During my current research in the lab of Prof. K. Delaplane I wish to learn about the indirect effect of varroa mites on plant pollination through its influence on bee foraging behavior.

A variety of cosmopolitan pests and diseases have contributed to a worldwide decline in honey bee populations. The available pest treatments are partially effective and only decrease pest loads without eliminating pests entirely. The outcome of this situation is that most colonies participating in crop pollination are infected to some degree. Facing these conditions we must be aware of the influence of nest invaders on pollination efficiency. One of the most common and virulent pests is the varroa mite (Varroa destructor). Delaying varroa treatments may lead to colony collapse, but even when treated a certain population of mites still exists inside the bee colony. Sublethal varroa infestations may interfere with pollination efficiency in several ways. In any case, the putative negative effects of varroa on pollinating performance may be mitigated by the eusocial colonial life structure of honey bees and by queen polyandry. My research is addressed to deal with the following questions:

  • Does varroa infestation affect foraging behavior at the individual bee level?
    Are putative effects at the individual level compensated at the colony level?
  • Does increased genetic diversity of the colony resulting from polyandry contribute to pest resistance and higher pollination efficacy?


  1. Afik, O., Dag, A., Yeselson, Y., Schaffer, A. and Shafir, S. 2009. Selection and breeding of honey bees for higher or lower collection of avocado nectar. Journal of Economic Entomology. (In-press).
  2. Afik, O., Hallel, T., Dag, A. and Shafir, S. 2009. The components that determine honey bee (Apis mellifera) preference between Israeli unifloral honeys and the implications for nectar attractiveness. Israel Journal of Plant Sciences. (In-press).
  3. Afik, O., Dag, A. and Shafir, S. 2008. Honey bee (Apis mellifera) round dance is influenced by trace components of floral nectar. Animal Behaviour. 75:371-377.
  4. Dag, A., Zvieli, Y., Afik, O. and Elkind, Y. 2007. Honeybee pollination affects fruit characteristics of sweet pepper grown under net-house. International Journal of Vegetable Science. 13:45-59.
  5. Afik, O., Dag, A. and Shafir, S. 2007. Perception of avocado bloom (Lauraceae: Persea americana) by the honey bee (Hymenoptera: Apidae: Apis mellifera). Entomologia Generalis. 30:135-153.
  6. Afik, O. and Shafir, S. 2007. The effect of ambient temperature on crop loading in the honey bee, Apis mellifera (Hymenoptera: Apidae). Entomologia Generalis. 29:135-148.
  7. Afik, O., Dag, A., Kerem, Z. and Shafir, S. 2006. Analyses of avocado (Persea americana) nectar properties and their perception by honey bees (Apis mellifera). Journal of Chemical Ecology. 32:1949-1963.
  8. Afik, O., Dag, A. and Shafir, S. 2006. The effect of avocado nectar composition on its attractiveness to honey bees. Apidologie. 37:317-325.
  9. Dag, A., Afik, O., Yeselson, Y., Schaffer, A. and Shafir, S. 2006. Physical, chemical and palynological characterization of avocado (Persea americana Mill.) honey in Israel. International Journal of Food Science and Technology. 41:387-394.
  10. Dag, A., Fetscher, E., Afik, O., Yeselson, Y., Schaffer, A., Kamer, Y., Waser, N.M., Madore, M.A., Arpaia, M.L., Hofshi, R. and Shafir, S. 2003. Honey bee (Apis mellifera) strains differ in avocado (Persea americana) nectar foraging preference. Apidologie. 34:299-309.
  11. Dvash, L., Afik, O., Shafir, S., Schaffer, A., Yeselson, Y., Dag, A. and Landau, S. 2002. Determination by near-infrared spectroscopy of perseitol used as a marker for the botanical origin of avocado (Persea americana Mill.) honey. Journal of Agricultural and Food Chemistry. 50:5283-5287.
  12. Dag, A., Lior, E. and Afik, O. 2002. Pollination of confection sunflowers (Helianthus annuus L.) by honey bees (Apis mellifera L.). American Bee Journal. 142:443-445.
  13. Shafir, S. and Afik, O. 1999. The effect of ambient temperature on crop load size in honey bees. In: Sommeijer MJ, Ruijter A (eds) Insect pollination in greenhouses. Soesterberg, Netherlands. pp:155-161.
  14. Afik, O., W. Hunter, and K.S. Delaplane. 2010. Effects of varroa mites and bee diseases on pollination efficacy of honey bees. Proceedings of the American Bee Research Conference, Orlando, Florida. American Bee Journal 150(5): 497



James D.Ellis, Jr.

Post-Doctoral Scientist
March 2004 - August 2006

  • B.S., 2000, University of Georgia, Biology, Honors
  • Ph.D., 2004, Rhodes University, Grahamstown, South Africa, Entomology

Present Position:
Assistant Professor
University of Florida

Dissertation title and abstract:

Ecology and Control of Small Hive Beetles (Aethina tumida Murray)

The small hive beetle (Aethina tumida Murray) is an endemic scavenger in colonies of honey bee (Apis mellifera L.) subspecies inhabiting sub-Saharan Africa. The beetle only occasionally damages host colonies in its native range and such damage is usually restricted to weakened/diseased colonies or is associated with after absconding events due to behavioral resistance mechanisms of its host. 

The beetle has recently been introduced into North America and Australia where populations of managed subspecies of European honey bees have proven highly susceptible to beetle depredation. Beetles are able to reproduce in large numbers in European colonies and their larvae weaken colonies by eating honey, pollen, and bee brood. Further, adult and larval defecation is thought to promote the fermentation of honey and large populations of beetles can cause European colonies to abscond, both resulting in additional colony damage. The economic losses attributed to the beetle since its introduction into the United States have been estimated in millions of US dollars.

Although beetles feed on foodstuffs found within colonies, experiments in vitro show that they can also complete entire life cycles on fruit. Regardless, they reproduce best on diets of honey, pollen, and bee brood. After feeding, beetle larvae exit the colony and burrow into the ground where they pupate. Neither soil type nor density affects a beetle’s ability to successfully pupate. Instead, successful pupation appears to be closely tied to soil moisture.

African subspecies of honey bees employ a complicated scheme of confinement (aggressive behavior toward and guarding of beetles) to limit beetle reproduction in a colony. Despite being confined away from food, adult beetles are able to solicit food and feed from the mouths of their honey bee guards. Remarkably, beetle-naïve European honey bees also confine beetles and this behavior is quantitatively similar to that in African bees. 

If confinement efforts fail, beetles access the combs where they feed and reproduce. Two modes of beetle oviposition in sealed bee brood have been identified. In the first mode, beetles bite holes in the cappings of cells and oviposit on the pupa contained within. In the second mode, beetles enter empty cells, bite a hole in the wall of the cell, and oviposit on the brood in the adjacent cell. Despite this, African bees detect and remove all of the infected brood (hygienic behavior). Similarly, European bees can detect and remove brood that has been oviposited on by beetles. Enhancing the removal rate of infected brood in European colonies through selective breeding may achieve genetic control of beetles.

Additional avenues of control were tested for efficacy against beetles. Reducing colony entrances slowed beetle ingress but the efficacy of this method probably depends on other factors. Further, the mortality of beetle pupae was higher when contacting species of the fungus Aspergillus than when not, making biological control an option. Regardless, no control tested to date proved efficacious at the level needed by beekeepers so an integrated approach to controlling beetles remains preferred.

The amalgamation of the data presented in this dissertation contributed to a discussion on the beetle’s ecological niche, ability to impact honey bee colonies in ways never considered, and the ability to predict the beetle’s spread and impact globally.


  1. Ellis, J.D., Jr. and K.S. Delaplane. 2001. A scientific note on Apis mellifera brood attractiveness to Varroa destructor as affected by the chemotherapeutic history of the brood. Apidologie 32: 603-604
  2. Ellis, J.D., Jr., K.S. Delaplane, and W.M. Hood. 2001. Efficacy of a bottom screen device, Apistan, and Apilife VAR in controlling Varroa destructorAmerican Bee Journal141(11): 813-816
  3. Ellis, J.D., Jr, K.S. Delaplane, H. R. Hepburn, and P. J. Elzen. 2002. Controlling small hive beetles (Aethina tumida Murray) in honey bee (Apis mellifera) colonies using a modified hive entrance. American Bee Journal 142(4): 288-290
  4. Ellis, J.D., K.S. Delaplane, and W.M. Hood. 2002.  A scientific note on small hive beetle (Aethina tumida Murray) weight, gross biometry, and sex proportion at three locations in the southeastern United States. American Bee Journal 142(7): 520-522
  5. Delaplane, K.S. and J.D. Ellis, Jr. 2002. The small hive beetle (Aethina tumida) in the United States: reduced hive entrances are a promising IPM strategy. Proceedings of the 6th European Bee Conference, International Bee Research Association
  6. Ellis, J. D. Jr., H. R. Hepburn, A. M. Ellis, and P. J. Elzen. 2002. Social encapsulation of small hive beetles (Aethina tumida Murray) by European honey bees (Apis mellifera). Insectes Sociaux 50:286-29
  7. Ellis, J. D. Jr., H. R. Hepburn, A. M. Ellis, and P. J. Elzen. 2002. Prison construction and guarding behavior by European honey bees is dependent on inmate beetle density.Naturwissenschaften 90:382-38
  8. Ellis, J.D., Jr., R. Hepburn, K.S. Delaplane, and P.J. Elzen. 2003. A scientific note on small hive beetle (Aethina tumida Murray) oviposition and behavior during honey bee (Apis mellifera) winter clusters and absconding events. Journal of Apicultural Research 42(1-2): 47-48 
  9. Ellis, J.D., Jr., R. Hepburn, K.S. Delaplane, P. Neumann, and P.J. Elzen. 2003. The effects of adult small hive beetles, Aethina tumida (Coleoptera: Nitidulidae), on nests and foraging activity of Cape and European honey bees (Apis mellifera). Apidologie 34: 399-408
  10. Ellis, J. D., Jr., K. S. Delaplane, R. Hepburn, and P. J. Elzen. 2004. Efficacy of modified hive entrances and a bottom screen device for controlling Aethina tumida (Coleoptera: Nitidulidae) infestations in Apis mellifera (Hymenoptera: Apidae) colonies. Journal of Economic Entomology 96(6): 1647-1652 
  11. Ellis, J. D., Jr., K.S. Delaplane, C.S. Richards, R. Hepburn, J.A. Berry, and P.J. Elzen. 2004. Hygienic behavior of Cape and European Apis mellifera (Hymenoptera: Apidae) toward Aethina tumida (Coleoptera: Nitidulidae) eggs oviposited in sealed bee brood.Annals of the Entomological Society of America 97(4): 860-864
  12. Ellis, J. D. and K. S. Delaplane. 2006. The effects of habitat type, ApilifeVAR™, and screened bottom boards on small hive beetle (Aethina tumida) entry into honey bee (Apis mellifera) colonies. American Bee Journal 146(6): 537-539
  13. Ellis, J. D. and K. S. Delaplane. 2007. The effects of three acaricides on the developmental biology of small hive beetles (Aethina tumida). Journal of Apicultural Research and Bee World 46(4): 256-259