Dr. Darrell Moore

Associate Professor

COURSES TAUGHT:

Experimental Animal Behavior, Animal Physiology,  Biology for Majors II, Topics in Organismal Biology, Neurobiology 

CURRENT RESEARCH PROJECTS:

My research interests are primarily concerned with determining how the nervous system controls behavior (neuroethology). Because the nervous system is so complex in the vertebrates, I have relied upon relatively simple animals (such as insects and crustaceans) as model systems. The simple system approach has been widely successful in neuroethology, revealing basic principles that are applicable to vertebrates as well as invertebrates.

Timekeeping in Honey Bees (field and laboratory studies)



Currently, I am devoting most of my research effort to addressing a number of questions concerning the development of circadian rhythmicity in honey bees and how the circadian rhythm is integrated into the complex division of labor within the colony. Much of the initial, fundamental work was done in collaboration with Drs. Gene Robinson and Susan Fahrbach at the University of Illinois. I have found that honey bees do not have a circadian rhythm immediately after emergence as adults but the rhythm appears later in life, before the worker bee becomes a forager. This makes biological sense for bees because, during early adulthood, the bees perform in-hive duties such as brood care, attending the queen, and general nest maintenance chores that need to be accomplished around-the-clock. However, when a bee ages and becomes a forager, a working circadian clock is an absolute necessity because the bee must remember the exact time of day that food sources are available and return to those sources on consecutive days.

I will be examining the development of rhythmicity in honey bees in more detail, using both physiological and behavioral approaches. Some of the experiments will be performed in the field, some in the lab, and some will have components of both.

Also, I will be examining the honey bee time-sense itself; that is, the ability of bees to accurately remember the time of day at which they receive food rewards. Some of my earlier work demonstrated that bees were exceedingly accurate in their time-memory early in the day but become somewhat less accurate as the day wears on. It would be useful to test the honeybee time-sense to determine exactly what sensory cues associated with the food reward are used in the marking of time into memory.



Some relevant questions:



• How are circadian rhythms of behavior integrated into the lifestyles of individual bees without disrupting or sacrificing task performance, essential to the division of labor?
  
  
• What causes the bee's circadian clock to "turn on" prior to the transition from in-hive tasks to foraging? Interestingly, there are significant changes in the neural organization of the brain (likely caused by an increase in blood levels of Juvenile Hormone) just before the bee becomes a forager. Can the onset of rhythmicity be advanced by administration of Juvenile Hormone?
  
  
• Environmental factors (such as the size of the foraging population within the colony) can accelerate or retard behavioral development in bees. Will these factors also accelerate or retard the ontogeny of circadian rhythmicity?
  
  
• There are two major possibilities concerning the onset of rhythmicity: 1.) The clock really is not functional at all until the foraging transition. 2.) The clock is alive and well before behavioral rhythmicity but it just isn't coupled to (plugged into) behavior until the appropriate developmental stage. I have some behavioral experiments in mind to differentiate between these two scenarios.
  
  
• Is there a genetic linkage among (1) time to onset of circadian rhythmicity, (2) the period of the circadian rhythm, (3) locomotor activity pattern, and (4) longevity? Preliminary evidence suggests that the answer is yes. More experiments are necessary.
  

• Do drones (haploid males) also show an ontogeny of circadian rhythmicity?

• What exactly do foragers do when they are not foraging? Do they perform any other task-related behaviors or are they just lounging around, saving energy for the next foraging excursion?

• Bees are highly social creatures. Are social cues used for synchronizing circadian rhythms?

Other Interests:



• Environmental influences on circadian rhythms in flies (with Dr. Karl Joplin)
• Insect neuroanatomy (requires microdissection)
• Aggressive behavior and establishment of dominance hierarchies in crayfish

Selected Publications:

Honeybee Behavior

Moore D, Penikas J, Rankin MA (1981) Regional specialization for an optomotor response in the honeybee compound eye. Physiological Entomology 6: 61-69.

Moore D and Rankin MA (1982) Direction-sensitive partitioning of the honeybee optomotor system. Physiological Entomology 7: 25-36.

Moore D, Angel JE, Cheeseman IM, Robinson GE, and Fahrbach SE (1995) A highly specialized social grooming honey bee. Journal of Insect Behavior 8: 855-861.

Honeybee Circadian Rhythms

Moore D and Rankin MA (1983) Diurnal changes in the accuracy of the honeybee foraging rhythm. Biological Bulletin 164: 471-482.

Moore D and Rankin (1985) Circadian locomotor rhythms in individual honeybees. Physiological Entomology 10: 191-197.

Moore D, Siegfried D, Wilson R, and Rankin MA (1989) The influence of time of day on the foraging behavior of the honeybee, Apis mellifera. Journal of Biological Rhythms 4: 305- 325.

Moore D and Rankin MA (1993) Light and temperature entrainment of a circadian locomotor rhythm in honeybees. Physiological Entomology 18: 271-278.

Moore D, Angel JE, Cheeseman IM, Fahrbach SE, and Robinson GE (1997) Timekeeping in the honey bee colony: Integration of circadian rhythms and division of labor. Manuscript submitted.

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