Behavioral Characteristics of Scent Marking Behavior in. The Mongolian gerbil (Meriones unguiculatus)

Transcription

1 Exp. Anim. 30 (2), , 1981 Behavioral Characteristics Scent Marking Behavior in Mongolian Gerbil (Meriones unguiculus). Hiroyuki YOSHIMURA Department Pharmacology School Medicine Ehime University Shizukawa, Shigenobu-cho, Onsen-gun, Ehime , Japan. (Received publicion : August 7, 1980) Behavioral characteristics scent marking behavior in Mongolian gerbil investiged using open-field apparus. gerbils raised in Japan exhibited a similar behavioral topography scent marking behavior to those observed in United Stes. incidence frequency marking behavior sexually dimorphic with predominance in males. A midventral sebaceous gl male also larger than th female. In male gerbils which has been housed with or males (4 animals per cage), frequency marking differed individually among cage mes. On or h, when two males having similar marking frequency housed in pairs one month, one two increased marking frequency compared with prepairing whereas or decreased it significantly. evidence tends to support notion th scent marking behavior is a species-common response in gerbils th behavior correle to dominance social ranking. Introduction Mongolian gerbil (Meriones unguiculus) is known to possess several behavioral characteristics different from or laborory rodents such as mice rs. Scent marking behavior is one m : gerbil marks low-lying objects in environment by rubbing m with a midventral sebaceous scent gl deposits a yellow-brown sebum with a musky odor. behavior has extensively been studied by Thiessen his colleagues [7-13], who concluded th marking behavior in gerbils is a speciescommon response closely reled to territoriality. However, Mongolian gerbil employed in United Stes origines from a few ming pairs which sent from Japan in 1954 [6] so th animals are closely inbred. Thus, re has been arisen a question wher or not re exist a generality in behavioral topography scent marking behavior between gerbils reared in Japan in America. However, little work on scent marking behavior in gerbils has been done in Japan. present study conducted to elucide this problem to investige biological significance marking behavior in gerbis. Merials Methods Mongolian gerbils (Meriones unguiculus) used in experiment born raised in our laborory. gerbils weaned between days after birth, housed with littermes. At approximely 35 days gerbils divided into male female subgroups. subjects housed in a 42 ~25 ~15cm polycarbone cages with a wire mesh top (4 animals per cage).

2 108 Fig. 1 a : Scent marking open-field cage shavings animals per ture 7 : 00 Behavioral using a by clear side from a 46 panel ning. leral Six (2.5cm intervals. wt) intensity an mounted led 60 approximely ease clear this clea- 0.6cm high), regular apparus above illuminion 250lux bulb on response (25 control center. marking a Plexiglass incescent cm enclo- observion open-field by wide, size made except allowed to illumined : 00 ( in rized by a slight spreading hind legs, coupled with a lowering abdomen over pegs. A single behavioral testing permed 10 min using a video monitor system (from 9 : 00 a. m. to 11 : 00 a. m.), a ler time, number ventral rubs to pegs rearing counted from video. After each trial pegs cleaned with a dilute alcohol solution. permed high), view. tached 7 which 60 ~60cm, cm 1.2cm Plexiglass removable pegs, long, which on m.). gray walls apparus maintained apparus repleni- cycle observion sed (light p. cage tempera- light-dark open-field constructed it, room wer. food from cleaning controlled f wood All to out rearing 23 }1 Ž, m., taken food automically a. access week shment with merial. free once covered bedding had wer, as behavior apparus; characte- Results When gerbil introduced into openfield apparus, gerbil exhibited high explorory behavior approached rapidly to one 6 pegs on. After sniffing peg gerbil lod his abdomen with a slight spreading hind legs, n rubbed midventral sebaceous gl over peg. marking response in open-field is shown in Fig-la. re significant difference in marking behavior between male female gerbils (Table 1). On or h, no significant differences in rearing activity defecion found between male female gerbils. size a

3 109 Table Average experiment 100 S. 1 D. 120 days Significance 'Chi-square test open-fieleld behavior conducted age from June time evalued by ually gl } 0.2cm sebaceous dimorphic : average 2.6 }0.3 gl U-test females cm also length (p<0.05). A July, all Each gerbil subjects 10 min. value nonparametric between shows mean } stistical analysis. Fig. 1 c : Midventral male after bet sebaceous shaving ween 100 scent hair. 120 days gl in subjects age. sex males to Mongolian observion. means ; 2Mann-Whiteny Fig. 1 b : Midventral sebaceous scent gl (arrow) in male (left) female (right) gerbils ; midventral in morpho- 2.0 logical shaving Fig-lb feure a sebaceous surrounding hair & c. gl after is shown in

4 110 Table 2 Individual difference in marking frequency among cage mes. Male gerbils housed communally in 4 animals per cage a period 60 days, subjects approximely 100 days age time observion. Fig. 2 Time course marking rearing activity in gerbils during 10 min test period. 9 male gerbils between days age used. Time course marking rearing activity in gerbils during 10 min test period is shown in Fig-2. In contrast to rearing activity which decreases with lapse time, marking frequency showed a reverse U-m histogram. When male gerbils housed toger with or males (4 animals per cage) after 35 days from birth, a striking individual difference observed as seen in Table 2. This phenomenon confirmed in all 6 cages employed in experiment. Fig-3 shows effect pairing on marking frequency in male gerbils. When two males which had a similar frequency marking bee pairing housed in pairs 30 days, it found th one m always increased his marking frequency more than in prepairing, while or decreased his marking frequency. An agonistic behavior observed during a few days after pairing. Discussion In present experiment, it confirmed th Mongolian gerbils which are available in Japan possess a similar behavioral topography scent marking response to those described previously in United Stes. evidence obtained

5 111 Fig. 3 Effect gpairing hon marking frequency in male gerbils. œ \ œgerbil with high frequency marking ; \ gerbil with low frequency marking. *Significance between two groups evalued by means nonparametric Mann-Whiteny U-test (p<0.01). by present author, ree, appears to support Thiessen's notion th scent marking behavior in gerbils is a speciescommon response [7]. Both marking activity gl size predominant in males, but no sex difference found in rearing activity defecion. Thiessen his co-workers have found th rogens from tests play an important role in manifestion marking response [1, 8, 10, 11, 12] ; castrion in males led to a striking reduction in marking frequency gl size, whereas both restored by replacement rapy with testosterone propione. However, neuro-reguling mechanisms marking behavior is uncertain. In previous work, present author found th centrally active anticholinergic drugs can suppress marking response (unpublished da). Thus, it seems th brain cholinergic system may participes in manifestion behavior. It is interesting th re arose a striking individual difference in marking frequency when only males housed communally a period. Scent marking in mammals has generally been considered an important m social communicion associed with individual recognition, dominance, territory [3, 5]. ree, individual differences among cage mes may suggest possible relionship between marking frequency social ranking. Indeed, it has been reported th social factor such as individual housing or high populion density alters marking frequency in gerbils [2, 4]. In connection with this, present da pairing experiment indice th marking behavior in gerbils correles to dominancy. Although a concept territoriality has repeedly been pointed out as an important factor in manifestion animal behavior re are some methodological difficulties in quantitive analysis to determine such as territoriality in mice rs. As evaluion scent marking response is easy, Mongolian gerbil appears to be an animal model suitable studying dominance territory. References [1] Blum, S. L., Thiessen, D. D. (1971). effect different amounts rogen on scent marking in male Mongolian gerbil. Horm. Behav., 2, [2] Hull, E. M., Langan, C. J., Rosselli, L. (1973). Populion density social, territorial, physiological measures in gerbil (Meriones unguiculus). J. comp. physiol. Psychol., 81, [3] Johnson, R. P. (1973). Scent marking in mammals. Anim. Behav., 21, [4] NyBy, J., Thiessen, D. D., Wallace, P. (1970) Social inhibition territorial marking in Mongolian gerbil (Meriones unguiculus). Psychon. Sci., 21, [5] Ralls, K. (1971). Mammalian scent marking. Science, 171, [6] Rich, S. T. (1968). Mongolian gerbil (Meriones unguiculus) in research. Lab. Animal Care,

6 112 18, [7] Thiessen, D. D. (1968). roots territorial marking in Mongolian gerbil : A problem species-common topography. Behav. Res. Meth. & Instru., 1, [8] Thiessen, D. D., Friend, H. C., Lindzey, G. (1968) Androgen control territorial marking in Mongolian gerbil. Science, 160, [9] Thiessen, D. D., Blum, S. L., Lindzey, G. (1 969). A scent marking response associed with ventral sebaceous gl Mongolan gerbil (Meriones unguicubtus). Anim. Behav., 18, [10] Thiessen, D. D., Yahr, P. (1970). Central control territorial marking in Mongolian gerbil. Physiol. Behav., 5, [11] Thiessen, D. D., Owen, K., Lindzey, G. (19 71). Mechanisms territorial marking in male female Mongolian gerbil (Meriones unguiculus). J. comp. physiol. Psychol., 77, [12] Whitsett, J. M., Thiessen, D. D. (1972). Sex difference in control scent-marking behavior in Mongolian gerbil (Meriones unguiculus). J. comp. physiol. Psychol., 78, [13] Yahr, P., Thiessen, D. D. (1975). Estrogen control scent marking in female Mongolian gerbils (Meriones unguiculus). Behav. Biol., 13,