Moniliformis moniliformis Infection Has No Effect on Some Behaviors of the Cockroach Diploptera punctata Author(s): Zachary Allely, Janice Moore and Nicholas J. Gotelli Source: The Journal of Parasitology, Vol. 78, No. 3 (Jun., 1992), pp. 524-526 Published by: The American Society of Parasitologists Stable URL: http://www.jstor.org/stable/3283658 . Accessed: 04/05/2013 10:55 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp . JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. The American Society of Parasitologists is collaborating with JSTOR to digitize, preserve and extend access to The Journal of Parasitology. http://www.jstor.org This content downloaded from 132.198.40.214 on Sat, 4 May 2013 10:55:35 AM All use subject to JSTOR Terms and Conditions RESEARCH NOTES J. Parasitol., 78(3), 1992, p. 524-526 ? American Society of Parasitologists 1992 Moniliformismoniliformis Infection Has No Effect on Some Behaviorsof the CockroachDiploptera punctata Zachary Allely, Janice Moore, and Nicholas J. Gotelli*, Departmentof Biology,Colorado State University,Fort Collins,Colorado 80523; and *Departmentof Zoology,University of Oklahoma,Norman, Oklahoma 73019 ABSTRACT: The behaviorof the cockroachDiploptera Experiments were conducted under 2 light punctataparasitized with the acanthocephalanMonil- conditions: white light and red light (Carmichael was examined for iformis moniliformis parasite-in- and Moore, 1991). The latter is thought to be ducedalterations. No significantdifference in behavior visible was found between parasitizedand unparasitizedan- outside the cockroach spectrum (Seelin- imals in the following behavioral tests: (1) choice of ger and Tobin, 1982), allowing roach observa- white/black, horizontal/verticalsubstrate under light tion in simulated darkness. and re- and dark conditions;(2) temporal directional Substrate choice under both red and white light to a choice between sponse brightlight source;(3) light was examined in an arena in which one-half of and dark (photophilia);and (4) activity (time spent moving, distance,and velocity). A comparisonof un- the floor and adjacent wall was black, the other infectedanimals under 2 light conditions showed that half was white. The response variable was the light affected the activity of uninfected animals and fraction of time spent on each of the 4 possible is their responseto substrate.Diploptera punctata the combinations of color and orien- first nondomestic cockroachto be examined for be- (black, white) havioral responses to Moniliformisinfection. This is tation (horizontal, vertical). the firstreport of an arthropodin which acanthoceph- The activity test involved a grid covering the alan infectionhas failedto alterbehavior under at least floor of a white arena (1 square = 5 cm2, desig- some common test conditions. nated with Cartesian coordinates). Insect loca- tion was recorded, with vertical positions noted The ability of acanthocephalans to alter ar- as the nearest horizontal square. From this we thropod intermediate host behavior is wide- determined the total number of movements, the spread (Holmes and Bethel, 1972; Moore and total distance moved, and average velocity (cm/ Gotelli, 1990). In a series of laboratory experi- sec) during periods of movement. ments (Carmichael and Moore, 1991; Gotelli and Phototaxis was examined in a white arena un- Moore, 1992), the behavioral responses of sev- der red light. A bright white light was placed eral cockroach host species to acanthocephalan above 1 point along the arena perimeter. Each (Moniliformis moniliformis) infection have been animal was acclimated in the center of the arena examined. In this study, we report the results of under an inverted opaque cup (5 cm diameter). such experiments with Diplopterapunctata (=Di- The light was then turned on and the cup lifted. ploptera dytiscoides), a viviparous, widespread Freeze time equaled the time between lifting the native of the South Pacific (Woodhead, 1984). cup and the first major movement of the animal, Maintenance of cockroaches, exposure to par- excluding cleaning behavior or turning in place, asites, and general experimental protocol fol- and represented the response time of the animal lowed the methods of Carmichael and Moore to the light. First direction of movement was (1991). Female cockroaches were not used be- scored on a scale of 0 (directly toward the light) cause of potential behavioral variation associ- to 6 (1800 away from the light). ated with reproduction (Lipton and Sutherland, Photophilia tests involved a black arena under 1970). white light, with 1 side covered by a black semi- Acanthocephalan eggs were obtained from circular sheet of Lexan approximately 15 cm stock originating in wild rats in the Houston Zoo- above the floor of the arena. The response vari- logical Gardens. Cystacanths from D. punctata able was roach location (light or dark portion of were fed to 2 4-mo-old white rats. Nine weeks the arena). later, 1 of these rats harbored M. moniliformis These experiments were designed to assess si- adults (4 gravid females and 1 male). Thus, the multaneous effects of light and parasitism on D. life cycle of M. moniliformis was completed suc- punctata behavior. Data were analyzed using a cessfully using D. punctata as an intermediate repeated measures ANOVA with the within-sub- host. jects factor being light (red or white) and be- 524 This content downloaded from 132.198.40.214 on Sat, 4 May 2013 10:55:35 AM All use subject to JSTOR Terms and Conditions RESEARCHNOTES 525 TABLEI. Behavioralscores for uninfected(n = 40) and infected (n = 35) Diplopterapunctata (mean ? SD). Unifected Infected Freeze time (sec) 31.0 ? 48.1 36.8 ? 44.7 % Time in light 33.8 ? 21.1 36.2 ? 24.9 Red light White light Red light White light Substrate choice (% time) Black horizontal 30.6 ? 20.4 39.0 ? 36.6 28.4 ? 20.0 48.9 ? 39.8 Black vertical 32.7 ? 24.5 38.9 ? 38.8 32.5 ? 28.5 31.6 ? 41.4 White horizontal 21.9 ? 15.9 10.4 ? 18.8 24.4 ? 16.7 11.6 ? 20.7 White vertical 18.5 ? 19.4 11.7 ? 24.9 14.7 ? 19.2 8.4 ? 22.1 Activity % Time inactive 14.5 ? 18.0 73.2 ? 28.8 17.1 ? 22.4 68.7 ? 32.6 Total distance (cm) 505 ? 615 1,714 ? 662 613 ? 745 1,625 ? 750 Velocity (cm/sec) 2.3 ? 1.11 2.22 + 0.60 2.03 ? 0.76 2.14 ? 0.71 tween-subjects factor being parasitism (parasit- and has not experienced the selective regime nec- ized or unparasitized). Unless otherwise noted, essary to generate such alterations. There are sample sizes were 40 uninfected and 35 infected problems with such a broad assumption that are animals. Percentages, distances and velocities, beyond the scope of this report (see Moore and and freeze times were arcsine square root-, log-, Gotelli, 1990). In addition, we doubt the "nov- and square root-transformed, respectively. A chi- elty" explanation to be relevant for the following square test was performed on phototaxis (direc- reasons: not only does M. moniliformis develop tion) data from 26 infected animals and 25 un- successfully in D. punctata, but D. punctata prob- infected animals. ably encounters M. moniliformis in nature, al- Results are summarized in Table I. The per- though the extent to which D. punctata partici- centage of time spent on 4 possible substrates pates in the natural life cycle is unknown. under red or white light did not differ between Naturally infected D. punctata have not been infected and uninfected animals, nor did the per- reported; to our knowledge, they have not been centage of time active, total distance moved, or sought. The cockroach can live near human average velocity (P > 0.10). Infected and unin- domiciles, and both rats (Ash, 1962) and Peri- fected D. punctata did not differ in directional planeta americana (Schaefer, 1970) on the Ha- (x2 = 5.392; df = 6; P = 0.49) or freeze time waiian islands are known to harbor M. monili- (mean square = 0.012; F = 0.17; P = 0.68) re- formis. Thus, all elements for M. moniliformis sponses to a bright light. There was no significant life cycle completion are present in the area, and difference between infected and uninfected D. D. punctata is likely to be exposed to shelled punctata in the percentage of time spent in light acanthors and to rat predation. (mean square = 0.005; F = 0.06; P = 0.80). The failure ofM. moniliformis to alter D. punc- Although parasitism produced no significant tata behavior probably is not the result of in- behavioral effect, uninfected animals were influ- appropriate behavioral tests. Infection with M. enced by light. Under white light, control ani- moniliformis has resulted in behavioral alter- mals spent less time on white horizontal surfaces, ation in every other arthropod examined to date spent proportionally more time active and trav- (Moore, 1984), including 4 other cockroach spe- eled greater distances than they did under red cies (Carmichael and Moore, 1991; Gotelli and light (P < 0.0001). Moore, 1992; Moore and Gotelli, 1992). The Novelty of association may be 1 explanation responses we investigated are commonly altered for the failure of M. moniliformis to alter D. and can be important components of host sur- punctata behavior under experimental condi- vival. tions. In other words, assuming that parasite- Additional field studies of D. punctata are induced behavioral alterations are species-spe- needed for understanding the possible relevance cific adaptations for parasite transmission, it of ecological traits to the apparent absence of could be argued that the D.