The Effect of Maternal Deprivation on the Behavior of Female Golden Hamsters (Mesocricetus auratus) in the Presence of Various Male Odors

PROJECT SUMMARYScent marking, an extremely important

communicative behavior in mammals, serves as a means of broadcasting signals or information. The golden hamster (Mesocricetus auratus) is a good model for understanding the role of odors because they have a diverse array of odor-generating structures. The objective of this project is to study the difference between maternally deprived and maternally nurtured female hamster pups in their response to particular male odors. Experimental groups will consist of hamster pups that have been weaned and separated from their mother at different times in their development. Data will focus on the number of vaginal and flank marks, the two major scent marks produced by female hamsters, as well as time spent investigating each male odor. Understanding the basis of scent marking—as either a learned or innate response—will be of value in our knowledge of the social behavior of hamsters.

Nicholas IzajYork College of Pennsylvania, Department of Biological Sciences

A possible correlation between the development of the female golden hamster and its scent marking behavior has yet to be examined. Numerous studies have concentrated on the causes of scent marking; however, relatively little is known about how the hamster was raised prior to experimentation.

The process in which an animal deposits a scent on or near another conspecific scent is the chief mechanism by which some animals communicate. The golden hamster is used as a classic example for studying olfaction and scent marking for several key reasons. Male hamsters have a broad spectrum of odor-generating structures, creating scents to which female hamsters have two scent marking behaviors, vaginal and flank. Each behavior exhibited by the female has distinct functions. For example, a vaginal mark is primarily made to signal reproductive readiness and flank marking is mainly related to the regulation of competitive interactions (Petrulis and Johnston 1997).

This proposal will specifically emphasize the development of female hamsters from pups to young adults. It is the purpose of this proposal to examine what specific scents cause scent marking to occur and to observe this among groups of hamsters that were weaned at different times.

INTRODUCTION

To compare maternally nurtured and maternally deprived young adult female hamsters in their response to various male odors by measuring

-number of vaginal marks -number of flank marks -time spent investigating

OBJECTIVE

Petrulis, A. and Johnston, R.E. 1997. Causes of scent marking in female golden hamsters (Mesocricetus auratus): specific signals or classes of information. Journal of Comparative Psychology 111:25-37.

Previde, E.P. and Poli, M.D. 1996 Social learning in the golden hamster (Mesocricetus auratus). Journal of Comparative Psychology 110:203-208.

Roberts, M.F. 1987. Hamsters: A Complete Introduction. T.F.H. Publications, Inc., Neptune City, NJ.

 

LITERATURE CITED

ACKNOWLEDGEMENTS

Brad Rehnberg, Ph.D. Faculty Mentor

RESEARCH DESIGN AND METHODS

REVIEW OF LITERATURE

30 sexually naïve female hamsters (5 months of age)

10 weaned at 3 weeks

Every female tested to each odor condition

Number of vaginal and/or flank marks will be recordedas well as time spent investigating each odor

Data will be compared and analyzed among experimental groups using Prism and INSTAT

10 weaned at 7 weeks

10 weaned at 5 weeks

Figure 1. Mean (+/- SE) number of vaginal marks produced by females to two male scents in Experiment 1 that stimulated marking compared to the clean control condition: flank scent (top) and rump scent (bottom). Data are shown for all 4 days of the estrous cycle. D1=diestrus 1; D2=diestrus 2; PE=proestrus; E=estrus ( taken from Petrulis and Johnston, 1997)

Figure 2. Mean (+/- SE) number of flank marks produced by females to two male scents that stimulated marking in Experiment 1 compared to the clean control condition: flank scent (top) and saliva/mouth scent (bottom). Data are shown for all 4 days of the estrous cycle. D1=diestrus 1; D2=diestrus 2; PE=proestrus; E=estrus (taken from Petrulis and Johnston, 1997)

• when individually tested, the hamster pups that interacted with a skilled mother had a remarkable effect on the acquisition of new feeding and social behavior (Previde and Poli, 1996)

• pups either interacting with an unskilled mother/inexperience litter mates or individually were not able to learn the new behavior efficiently (Previde and Poli, 1996)

• females, when introduced to a variety of male odors, only responded with scent marking to a limited number of the odors presented to them (Figures 1 and 2, Petrulis and Johnston, 1997)

• several studies indicated that among rats and mice the presence of an experienced adult could promote learning by inexperienced pups (Previde and Poli, 1996)

• investigation of odors (Table 1) did not vary significantly over the estrous cycle in any odor conditions (Petrulis and Johnston, 1997)

Table 1 (Petrulis and Johnston, 1997)

Time Spent Investigating Eight Different Male Scents Across 4 Days of the Estrous Cycle

Mean investigation time (+/-SE)

Specific scent Diestrus 1 Diestrus 2 Proestrus Estrus F(1,9) p

Rump 56.4 (6.3) 57.4 (5.5) 47.2 (4.7) 54.8 (6.5) 1.097 0.411

Flank 48.0 (4.2) 44.5 (5.7) 51.5 (3.5) 63.4 (8.0) 1.498 0.296

Feces 50.2 (10.7) 45.5 (6.7) 34.6 (3.4) 33.5 (3.7) 1.368 0.329

Ano-genital 43.4 (5.1) 37.8 (5.8) 42.9 (5.7) 42.9 (5.5) 0.404 0.754

Ear 35.8 (4.7) 38.5 (7.6) 32.4 (3.8) 47.5 (7.8) 1.498 0.296

Foot 37.2 (3.8) 33.1 (3.0) 33.9 (2.9) 30.4 (4.1) 0.751 0.556

Saliva/mouth 31.6 (3.6) 30.0 (3.6) 30.1 (4.2) 33.9 (7.2) 0.118 0.947

Urine 21.2 (6.5) 18.9 (3.5) 18.5 (4.1) 14.1 (2.9) 1.531 0.289

EXPECTED RESULTS• time spent investigating each odor condition over the estrous cycle will be greater for those weaned earlier

• the number of vaginal and flank marks will vary for each experimental group, with more marks produced by those weaned earlier

• for those weaned at 5 and 7 weeks, vaginal and flank marks will be similar to previous studies

+

30 male hamsters(9 months of age)each assigned to

one female

Estrous cycle determined

Housed separately

Stimulus collected from males(flank gland, ear gland, mouth,

ano-genital area rump, foot, urine, feces)

Testing:All odor conditionClean condition

Specific odor

10 minute trial

Test a series of 12 test conditions on 4days each (one day for each day of

estrous cycle)

Female habituated to testingapparatus (10min/day) (4 days)