Fruit Fly Larvae Foraging

Dr. C. A. L. Riedl

Given the intimate link between genes and behavior, single gene mutations can have drastic effects on the behavior of organisms. In fruit flies (Drosophila melanogaster), genetic variation at the foraging (for) locus produces dimorphic larval foraging locomotion. This video clip shows the pronounced behavioral difference between “rover” versus “sitter” larvae, and it depicts the behavioral assay employed by Maria Sokolowski and her collaborators in examining the behavioral genetics of fruit fly foraging behavior. Mutations of a gene encoding a soluble guanylyl cyclase subunit of a cGMP-dependent protein kinase increased the activity of that protein kinase and foraging locomotion in larvae from both rover and sitter strains. The exact genes that are differentially transcribed as a result of that mutation are strain-dependent, however, indicating that genetic background has a tangible effect on the molecular effects of a mutation.

FURTHER READING: Lee A. Dugatkin, Principles of Animal Behavior, 3rd ed. (New York: W. W. Norton, 2013), chap. 2, “The Evolution of Behavior”; chap. 4, “Molecular Genetics and Development.” C. A. L. Ried, S. J. Neal, A. Robichon, J. T. Westwood, and M. B. Sokolowski, “Drosophila soluble guanylyl cyclase mutants exhibit increased foraging locomotion: Behavioral and genomic investigations,” Behavior Genetics 35 (2005), pp. 231–244.

Honeybee Hygienic Behavior

Rob Currie, Jaclyn Deonarine; University of Manitoba

The hygienic behavior of honeybee (Apis mellifera) workers provided some of the first compelling evidence that even relatively complex behavior can be encoded genetically. Honeybee hives are susceptible to infection with a disease known as American foul brood, caused by the spread of the bacterium Bacillus larvae. Left unchecked, the bacterium spreads throughout brood in the hive, leading to the demise of the colony. Some strains of bees, however, are resistant to this disease given the hygienic behavior of workers that detect and remove infected brood before the bacteria spread. Upon detection, hygienic workers uncap the brood cell and remove the diseased larva or pupa from the hive. Uncapping and removal were demonstrated to be under the control of separate genetic loci that segregate and assort independently as revealed by classic Mendelian dihybrid ratios among behavioral phenotypes in controlled crosses of hygienic and nonhygienic strains of bees.

FURTHER READING: Lee A. Dugatkin, Principles of Animal Behavior, 3rd ed. (New York: Norton, 2013), Chap. 4, “Molecular Genetics and Development.” W. C. Rothenbuhler, Behavior genetics of nest cleaning in honeybees. IV. Responses of F1 and backcross generations to disease-killed brood, American Zoologist 4 (1964), pp. 111–23.

Prairie Vole Mate Choice

Frank R. Castelli; Nancy G. Solomon Lab, Miami University

Here, we see a female prairie vole (Microtus ochrogaster) being subjected to a partner preference test, in which the female ultimately chooses to settle with the tethered male on the right and moves the vast majority of bedding material into his chamber. Using such sensitive simultaneous-choice assays, Castelli et al. 2011, demonstrated that females preferentially chose males with longer AVPR1A microsatellites. Such a preference would prove adaptive for females because males with longer AVPR1A microsatellite alleles spend more time with their female social partner, sire offspring with fewer females, and provide more paternal care than males with shorter AVPR1A microsatellite alleles.

FURTHER READING: Lee A. Dugatkin, Principles of Animal Behavior, 3rd ed. (New York: Norton, 2013), Chap. 4, “Molecular Genetics and Development”; Chap. 8, “Mating Systems.”  F. R. Castelli, R. A. Kelley, B. Keane & N. G. Solomon, Female prairie voles show social and sexual preferences for males with longer AVPR1A microsatellite alleles, Animal Behaviour 82 (2011), pp. 1117–26.