Territoriality and courtship behavior in male Anartia fatima (Nymphalinae)

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Territoriality and courtship behavior in male Anartia fatima (Nymphalinae)

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Title:
Territoriality and courtship behavior in male Anartia fatima (Nymphalinae)
Translated Title:
Territorialidad y comportamiento de cortejo en los machos Anartia fatima (Nymphalinae)
Creator:
Cristianne Frazier
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Subjects / Keywords:
Butterflies--Behavior
Mariposas--Comportamiento
Butterflies--Reproduction
Mariposas--Reproducción
Costa Rica--Puntarenas--Monteverde Zone--San Luis
Costa Rica--Puntarenas--Zona de Monteverde--San Luis
Tropical Ecology Spring 2001
Ecología Tropical Primavera 2001

Notes

Abstract:
Chasing behavior in butterflies may be the result of territorial defense or simply the result of mate location. Such aggressive behavior is frequently observed in male Anartia fatima. It was hypothesized that older male Anartia fatima would be more aggressive than younger males, who have less to lose if they do not defend access to females. Behavioral observations were made on 38 males. Multiple regressions were run to see how age and ambient conditions affected the behavior of the males. Older males were found to be more aggressive and spend more time in courtship, but it could not be concluded that the aggressive behavior in Anartia fatima was ultimately a result of the need to defend a territory to gain access to females. It is more likely that "aggressive" behavior is actually chasing as part of mate location and courtship behavior. Any benefits a male receives from being inherently "aggressive" as a result of the demands of courtship are secondary. Temperature was the abiotic condition factor to exhibit the most significant impact on the behavior of males. Increasing temperatures tended to result in an increase in the amount of time a male spent off of his perch and an increase in the maximum distance between perches. ( ,,,,,,,,,,, )
Abstract:
Es posible que el comportamiento de persecución en mariposas sea el resultado de la defensa del territorio o de la localización de las compañeras. Este comportamiento agresivo fue observado frecuentemente en machos de Anartia fatima. La hipótesis fue que los machos viejos son más agresivos que los machos jóvenes. Las observaciones de comportamiento fueron hechas en 38 machos. Las pruebas de regresión múltiple mostraron como la edad y las condiciones físicas afectaron el comportamiento de los machos. Los machos viejos fueron más agresivos y pasaron más tiempo cortejando, pero no se puede concluir que el comportamiento agresivo en A. fatima es el resultado de territorialidad. Es posible que el comportamiento "agresivo" sea el resultado de la búsqueda de compañera y de cortejo. Cualquier beneficio que el macho recibe por ser inherentemente agresivo como resultado de sus demandas en cortejo, son secundarias. La temperatura fue el factor abiótico que exhibe el impacto más significativo en el comportamiento de machos. Un aumento en la temperatura da como resultado un aumento en el tiempo que el macho gasta en su percha y un aumento en la distancia máxima entre perchas.
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Department of Zoology, University of Wisconsin-Madison

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TERRITORIALITY AND COURTSHIP BEHAVIOR IN MALE Anartia fati ma NYMPHALINAE Cristianne Frazier Department of Zoology, University of Wisconsin Madison _______________________________________________________________ ABSTRACT Chasing behavior in butterflies may be the result of territorial defense or simply the result of mate location. Such aggressive behavior is frequently observed in male Anartia fatima. It was hypothesized that older male Anartia fatima would be more aggress ive than younger males, who have less to lose if they do not defend access to females. Behavioral observations were made on 38 males. Multiple regressions were run t o see how age and ambient condi tions affected the behavior of the males. Older males were f ound to be more aggressive and spend more time in courtship, but it could not be concluded that the aggressive behavior in Anartia fatima was ultimately a result of the need to defend a territory to gain access to females. It is more likely that "aggressiv e" behavior is actually chasing as part of mate location and courtship behavior. Any benefits a male receives from being inherently "aggressive" as a result of the demands of courtship are secondary. Temperature was the abiotic condition factor to exhibit the most significant impact on the behavior of males. Increasing temperatures tended to result in an increase in the amount of time a male spent off of his perch and an increase in the maximum distance between perches. RESUMEN Es posible que el comportamiento de persecucin en mariposas es el resultado de la defensa del terri torio o de la localizacin de las compaeras Este comportamiento agresivo fue observado frecuentemente en machos de Anartia fatima. La hiptesis fue que ma chos viejos son ms agresivos que machos jvenes Las observaciones de comportamiento fueron hechas e n 38 machos. Pruebas de regresi n mltiple mostraron como la edad y las condiciones fsicas afectaron el comport amiento de los machos. Machos vi ejos fueron mas agresivos y pasaron mas tiempo cortejando, pero no se puede concluir que el comportamiento agresivo en A. fatima es el resultado de territorialidad. Es posible que el comportamiento "agresivo" es el resultado de la bsqueda de compa era y de cortejo. Cualquier beneficio que el macho recibe por ser inherentemente agresivo como resultado de sus demandas en cortejo, son secundarias. La temperatura fue el factor abitico que exh ibe el impacto ms significativo en el comportamiento de mach os. Un aumento en la temperatura da como resultado un aumento en el ti e mpo que el macho gasta en su percha y un aumento en la distancia mxima entre perchas. INTRODUCTION When an animal defends a resource by fighting or making displays it is described as t erritorial behavior Krebs and Davies, 1981. Typically, animals defend a territory that contains a valuable resource which will increase their reproductive success Alcock, 1984. This type of behavior has costs, such as energy expenditure and risk of inj ury, as well as benefits, like priority to access of resource, including mates. These two factors must be weighed to determine whether the organism is truly benefiting from territorial behavior. In areas of high resource availability there is no point in b eing territorial because there is

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enough of the resources for eve ryone Krebs and Davies, 1981. Often the strategy adopted by an individual depends on the strategy adopted by the rest of the population Krebs and Davies, 1981. If all conspecifics are def ending a resource, then it would be hard for an individual to obtain access to those resources unless it had a territory of its own. However, these ideas are not mutually exclusive. For a species that is territorial, those that do not maintain a territory usually suffer lower fitness. An individual might accept its role as a subordinate after a territorial dispute if their lifetime fitness is somehow maximized. Therefore, young and inexperienced individuals are more inclined to walk away from disputes unti l they are older, larger, more experienced and therefore, more likely to win Alcock, 1984. Territoriality in Lepidopterans has been a widely debated topic. It has been proposed that €joint spiral flights of butterflies are part of courtship, but others have associated these flights with aggression and territoriality Monge Mojera et al, 1998. Scott 1986 believes that chasing behavior of male butterflies is interpreted as aggressive and territorial, when actually it is enhancing the mate finding and c ourtship of males. Typically, males and females of a species are drawn to the same habitat to copulate. Those that are genetically disposed to avoid these reproductive sites will not be as fit Scott, 1986. Aggressive behavior has been witnesses in the b utterfly species Anartia Fatima Nymphalinae, a common butterfly of disturbed areas in Costa Rica and Panama. Males are generally seen perched on low vegetation and will chase other conspecifics, as well as other butterflies, birds, and even people Seilb erglied, 1983; DeVries, 1987. There has been some debate as to whether this is territorial behavior. A study done by Erin Haase 1999 looked at the amount of foraging and defensive behavior that occurred at different sized patches of Lantana camara Verb enaceae the preferred food of A. Fatima She found that A. f atima spent more time in resource patches than all other Lepidopteran species. She also found that males displayed more aggressive behavior in patches with more L. camara However she could not conclude that the males were actually defending the food resource without looking more in depth at their spatial distribution. It may not be that the males were defending only the food resource; they may have been defending a territory to gain access to fe males. Since females can be expected to frequently visit a preferred food source, males that defend a territory in that area may have priority over females. This study looks more closely at the variation in degree of aggressiveness between male Anartia fa tima of different ages. In congruence with Alcock‚s theory, it is hypothesized that young and inexperienced males will exhibit less aggressive behavior than older, more experienced males. This study also looks at the differences in energy and time budgets of males of different ages. It is hypothesized that older males will spend more time in courtship, as a result of increased aggressiveness. MATERIALS AND METHODS From April 17, 2001 to May 3, 2001, Anartia fatima were observed between 10:00AM and 2:00 PM daily in the pastures of San Luis, Costa Rica. Data on thirty eight males were collected during this time. Because only males chase interlopers Hasse, 1999, males were identified as those individuals that were s een chasing other insects or birds. In a few cases, the individuals never gave chase. These A. fatima were captured after observation and sexed by examining the abdomen and prothoracic legs through a hand lens. On the penultimate segment of males there are two ventral valve or €claspers, which open to

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expose the male organs. At the end of the female abdomen there are three openings: the anus, the egg pore, and the copularoty pore DeVries, 1987. Sexes can also be distinguished by the morphology of the pr othoracic legs. Males have fully scaled legs, while female legs are bare at the tip and have barbs Seilberglied, 1983. Both male and female Anartia Fatima have white or yellow bands on their wings. Because the bands are bright yellow upon eclosion and f ade as they age Seilberglied, 1983, the relative age of individuals could be identified. Paint chips were obtained and a color scale was created by assigning different values to different shades of yellow: 1 = a bright shade of yellow, 2 = a shade of yel low that was slightly less brilliant, 3 = a shade of yellow that was nearly white, 4 = the whitest of whites. When in the field, the color of the wing band of each male was compared to the color scale and the individual was assigned an age of 1, 2, 3, or 4 relatively, with 1 being the youngest and 4 being the oldest. Since behavior may vary based on the kind of condition the butterfly is in as well, wing wear was used as an indicator of the condition of the individual. A relative measure of wing wear was m ade by assigning a value of €1 to individuals with new wings, a €2 to individuals with intermediate wing wear, and a €3 to those with very worn wings. To avoid repeated observations on a single individual in any one condition of age or wing wear, obser vations were made in four different pastures, each on different days. I would return to one pasture after spending three days in other pastures and by doing this I avoided collecting data on the same individuals for three days in a row. A. fatima lives onl y 38 days. I assumed that after three days the butterflies would have aged enough to make the color of wing band, wing wear, and behaviors different from any observations made three days prior. Using a stop watch, a Dictaphone, and a hand counter, the fol lowing were recorded during the five minutes that I watched each male: 1 Amount of time spent feeding. It was considered feeding behavior when a male was perched on a flower or in a puddle with its proboscis in the substrate. 2 Amount of time spent in courtship. Courtship behavior involves a male rubbing up against another female A. fatima while she is perched, fluttering above a perched female possibly in an attempt to transferring pheromones Scott, 1986, or hovering in the air above a female who is fluttering below him. 3 Amount of time off of perch not including time in courtship or time feeding, only time in flight. 4 Number of different perches not including returns to the same perch. 5 Number of interlopers near the perch or flight path of the individual. 6 Number of chases of interlopers. The farthest distance m between two different perches was also measured. The ambient temperature and wind speed in the center of the territory and the time of day at which each male was observed wa s also recorded. A ratio of number of chases: number of interlopers was calculated for each male. Males that chased more of the interlopers that came near their perch or flight path were considered more aggressive at defending a territory or more motivated to mate because they spent more energy than others keeping interlopers out of an area. To identify the appropriate independent variables, using a correlation matrix, covariance was tested for between the independent variables of age, wing wear, number of interlopers, temperature, wind speed, and time of day. Dependent variables were: time off perch, number of perches, number of chases, time feeding, time in courtship, size of territory, and number of chases / number of interlopers. A series of multiple re gressions was run testing all independent variables together against each individual dependent variable. To determine which multiple regression best predicted the dependent variable, the independent variable with the highest p value in each regression was eliminated and then

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another regression was run against the same dependent variable. This was continued until a multiple regression model with the lowest possible p value was determined Zar, 1984. RESULTS Age and Wing Wear A correlation matrix for age, number of interlopers, temperature, wind spee, and age revealed that age and wing wear were positively correlated. y = .817 + .433X, R^ 2 =.686 P < .0001, N =38; See figure 1. Therefore, to avoid, problems of intercorrelation in the multiple regressions Zar, 1984, age was randomly selected over wing wear as and independent variable for multiple regressions. Multiple regressions began with five independent variables: age, number of interlopers, temperature, wind speed, and ti me of day. Time Off Perch Temperature was the most important variable influencing the amount of time males spent off of their perch y = 228.887 + 10.95X, R^2 = .164, P = .0116, N = 38 see figure 2. The significant p value indicates that as temperature i ncreases males spend more time off of their perches flying. However, the correlation coefficient R^2 = .164 shows that there is a lot of variation between the variables indicating a week relationship. On average males spent 94.447 seconds N = 38 off of their perch. The mean temperature was 29.5 Celsius N = 38. At the highest temperature recorded, 40.0 Celsius, the male spent 282 seconds off his perch. At 23.1 Celsius, the lowest temperature recorded, a male spent only 15 seconds off his perch. Age al so had a significant impact on the time off perch when tested with temperature in a multiple regression Age: P = .0068, Temperature: P = .0011 as temperature and age increased, males spent more time off of their perches flying. Time In Courtship Age of adult males had the most significant impact on the amount of time spent in courtship y = 1.721 + 2.782X, R^2 = .111, P = .0414 N = 38; see figure 3. The average amount of time spent in courtship for all age groups was 4.868 seconds N = 38. Males of ag e one spent an average of 1.667 seconds in courtship N = 15 while males of age four spent an average of 9.167 seconds in courtship N = 12. The significant p value P = .0414 indicates that as the age of males increases, so does the amount of time spen t courting females. The correlation coefficient R^2 = .111 shows that there is a lot of variation between the variables and therefore, the relationship is not extremely strong. A simple regression between time in courtship vs. number of chases: number o f interlopers was also run to see if more aggressive males spent more time in courtship. There was no significant difference between these two variables y = 3.124 + 6.193X, R^2 = .019, P = .4116, N = 38. This means that aggressive males may not necessari ly spend more time in courtship than non aggressive males. Farthest Distance Between Perches Temperature had the most significant impact on the distance between perches y = 53.258 + 2.303X, R^2 = .266, P = .0009, N = 38 see figure 4. The average temper ature was 29.5 Celsius and average distance was 14.69 meters N = 38. The highest temperature

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recorded, 40.4 Celsius, also correlated to the highest distance, 80 meters. There was a positive correlation R^2 = .266 between these two variables and a signi ficant p value P = .0009, indicating that although the relationship is weak due to high variation, a temperature increase results in an increase in the distance between perches. Number Of Chases: Number of Interlopers Out of the all the independent vari ables tested, age was the most important factor influencing aggressive behavior y = .126 + .066X, R^2 = .126, P = .0285, N = 38; see figure 5. The average ratio of cha ses: interlopers was .282 N = 38. For age one, the average aggression ratio was .229 N = 15. The average ratio for males of age four was .395 N = 12. A significant P = .0285 indicates that as males get older, they are more aggressive. The correlation coefficient R^2 = .126, indicates that their relationship may be weak due to high le vels of variation. Number of Perches Wind speed was the most influential variable in determining how many different perches a male had. However, this was not a significant relationship y = 3.504 + 334X, R^2 = .075, P = .0968, N = 38. The average number of perches an individual male had was 4.079 N = 38. The average wind speed was 1.7 miles/hour N = 38. The correlation coefficient R^2 = .075 shows that there is a trend for the number of perches to increase as wind speed increases. Number of Chases Although none of the independent variables had a significant impact on the number of chases a male made, the most significant variable was time of day y = 769773. 158 ƒ 2.505x10^ 4X, R^2 = .078, P = .0889, N = 38. The average number of chases from 10: 30 AM to 11:59AM was 3.29 N = 17. The average number of chases from 12:00PM to 1:30PM was 2.57 N = 21. The correlation was negative, indicating that as the day progresses from 10: 30 AM to 1: 30 PM relatively, there may be trend for the number of chases to decrease. Time Feeding Time of day was the most influential variable effecting time feeding, but this was just shy of being a significant relationship y = 11887200.526 + .004X, R^2 = .099, P = .0541, N = 38. The average time feeding from 10:30AM to 11:59PM was 15.47 seconds. The average time feeding from 12:00PM to 1:30PM was 34.619 seconds. It shouldn‚t be ignored that there is a trend between these two variables P = .0541. This indicates that as time of day increases, males may spend more time fe eding. Courtship Behavior During observations of courtship behavior of A. fatima females were seen to be very illusive. Females and males would spiral into the air and then the female would dart away. Often the male would lose sight of her and fly around aimlessly or return to the ground. Other courtship behavior included males rubbi ng up against perched females and hovering above them, most likely transferring pheromones Scott, 1986. Pairs of courting males and females were also seen in the air, the male hovering above the female. On four occasions, this same behavior was observed between three individual Anartia fatima Twice the activity was seen to end in one individual chasing another individual away. The sexes of

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these individuals could not be identified because there is very little sexual dimorphism between the male and female but it was assumed that one male was chasing another male away. I also frequently observed a male chasing interlopers out of an area until a female came along, at which time it would abandon the area and go into courtship with the female. Shortly after, another male would enter the area and begin chasing interlopers. DISCUSSION The correlation between age and wing wear is an obvious one; the longer an individual has been alive, the more time it has had to be a predators attempted prey, get into interac tions with other butterflies that would cause the wings to be damaged, or be worn and torn by the everyday trials of butterfly life. Spiral flights between two or more individuals were often observed. During these interactions, scales may be rubbed of an i ndividual‚s wings. In Figure 1, some individuals of younger ages are seen to have a high wing wear. This could be due to predators randomly preying on A. fatima of any age, or perhaps some of these younger individuals were more active than usual. Age The older a male is, the more aggressive it tends to be, based on a measurement of number of chases: number of interlopers Figure 5. The high degree of aggressiveness in older males supports the hypothesis proposed in this paper. What it does not prove is th at the €aggressive behavior of male A. fatima is the result of an inherent territoriality. Territoriality is defined as the active defense of an exclusive area that has economic value Krebs and Davies, 1978. This economic value could be in terms of food resources or access to mates. In the case of Anartia fatima it has not been shown that the butterflies are defending access to either of these two things. If the butterflies had visible fighting structures that were used in specific interactions, we migh t be able to conclude the particular reason, or reasons, for the use of those structures and therefore, the object of the butterflies‚ defense. But the aggressive chases of the male Anartia fatima are somewhat ambiguous. Males will chase a variety of interlopers and it is hard to identify the purpose of the chase. One possibility is that the male may be defending a food resource as proposed by Hasse 1999. Another possibility is that the male is a ctively trying to keep other males, or interlopers that might interfere with the flight path of a female, out of the area, as experiments by Davies supports Price, 1984, Krebs and Davies, 1978. It could also be an attempt to engage in courtship with a fe male, as Scott 1986 hypothesizes. In many cases, males identify females based on the learned shape or color of the females of the same species. The males will then pursue anything resembling a female Scott, 1986. I suspect that the reason for the male‚ s €aggression is related to achieving reproductive success, but not necessarily through the active defense of a territory. The age of a male had a strong effect not only degree of aggressiveness, but also on the amount of time spent in courtship with fem ales. Older males tended to spend more time in courtship Figure 3, which also supports my hypothesis. Older males may invest more time in courtship attempting to persuade a female to copulate with them because they have more to lose if they are unsuccess ful. For example, a younger male who encounters a somewhat unreceptive female may give up his attempt to copulate with her and spend his time feeding instead because he knows that he will have more chances in the future. But an older male will invest more time in convincing a female that he is an adequate mate

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because he knows that if he does not breed now, he may not be able to breed later. Aggressiveness and time in courtship were not significantly correlated. This means that the degree of aggressiveness of an individual male doesn‚t necessarily mean that the male will spend more time in actual courtship behavior with females. It is possible that with a large population size and more observations of duration of courtship behavior, a correlation might be se en. I suspect that there is a significant relationship between these two variables. The fact that older males are partitioning their time differently than younger males, that is, they are spending more time in courtship behavior, suggests that reproductive success is dependent on the males ability to properly court a female. It is likely that the male‚s ability to successfully court a female is directly related to the chasing behavior of older males. Scott 1986 suspects that the degree to which a female resists courtship may be an important factor in determining the degree of €aggressiveness in males. Unreceptive females tend to have more complicated courtship. They may perform a variety of maneuvers to avoid the male. Such €rejection dances may involve the female flying vertically up into the air with the male behind her, and then darting down causing the male to lose sight of her. Vertical flights of the female may also resemble those of males, convincing the pursuing male that he is in fact chasing a male. Females may also deter a male through chemical means. Simple courtship usually involves a male landing next to a female, and if she is ready, the two copulate. Those females with complicated courtship will copulate with a male if he lasts through the prolonged mating ritual Scott, 1986. Therefore, those males which spend more time courting a female will be more persistent and assertive, and inevitably reproductively more successful. The observations of A. fatima courtship support the idea that fema les have complicated courtship. It is then likely that the most persistent and assertive of males are those that are reproductively successful and are selected for. This implies that the ultimate force driving the selection of €aggressive behavior in male A. fatima is the females complicated. Therefore, the chasing behavior observed in A. fatima males should not be considered an aggressive act in defense of a resource, but rather a persistent maneuver in the attempt to court a female. These two ideas are not mutually exclusive. The chasing behavior exhibited by males has a variety of implications. As the courtship requirement of female becomes more complicated, the male will become more assertive. This can lead to an increase in the chasing behavior of the male, making it more likely that its objects of pursuit will become less specific. Males may chases not only anything that resembles a female, but maybe anything that moves within its field of vision. This would explain why A. fatima will chases not only other butterflies which come near its perch, but also other insects, bird, and even people Seilberlied, 1983; DeVries, 1987. Males may benefit from keeping interlopers out of an area where females frequently visit. On numerous occasions, smaller butterf lies were seen chasing female A. fatima If a male can keep these interlopers out of an area, then it may increase the likelihood that females will remain in the area long enough for the male to locate her and begin courtship. Within this context, chasing behavior could be considered a territorial act, but only if the reproductive success of the male is increased by keeping interlopers out of an area. The fact that older males were more €aggressive, and chased more of the interlopers that it encountered su ggests that there may be reproductive benefits for an older male if he keeps an area free of interlopers. Older males also spent more time off of their perch, possibly looking for females, looking for interlopers to chases out of the area, or both.

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If mal es were actively chasing other males of the same species out of an area where females frequently visit, this would support the idea that territoriality is directly increasing the reproductive success of a male. However, there is no evidence from this exper iment that male A. fatima were targeting only conspecific males. This could be tested by looking at specific interactions, noting the age of each individual, the winner and loser of the dispute, and identifying the sex of the loser males often chase females, and we would be inter ested in knowing the results of a male male dispute. If older males were the more frequent winner, this would support Alcock‚s theory, which states that in a territorial species, the younger individual is more likely to accept its role as a subordinate, w hile the older individual maintains the territory. Because courtship requirements vary from species to species, so does the degree of chasing behavior or aggressive behavior. I also suspect that the variation in courtship requirements can directly indicat e whether the chasing behavior is in fact aggressive and territorial or the mate finding strategy of a male. In order to determine whether an aggressive behavior is in fact territorial or not, one must look in depth into the behavior of the female and what type off pressures she is putting on the male. In the case of A. fatima males were frequently observed abandoning their posts to go into courtship with females. This may indicate that the defense of a territory may only be necessary until a female is lo cated, and then the real test of persistence and assertiveness begins. Even if a male A. fatima could chase every interloper out of an area, if he cannot last through the long and complicated courtship, he won‚t reproduce. The defense of access to females, and therefore a territory, may be more common among species with simple courtship. If females are quick to mate with the first male that approaches her, then a male would want to actively defend an area that females frequently visit in order to increase h is chances of being that €first male and therefore the reproductive male. To look further into this, comparisons between aggressive species with different courtship requirements must be done. For instance, Pararge aegeria Satyridae is believed to defen d a territory in order to gain access to females Price, 1984; Krebs and Davies, 1978. Males will chases intruding males out of an area if the intruder doesn‚t automatically retreat after sensing that the area is already the territory of another male. I s uspect that this species has a simple courtship compared to A. fatima and that, in part, would explain why males are more aggressive and territorial than A. fatima Ambient Conditions Temperature greatly effects the energy budgets, and therefore the beha vior of butterflies, which are poikilothermic or €cold blooded Scott, 1986; Price, 1984; Stoffolano, 1998. When the body temperature of a butterfly begins to drop, the individual usually perches with its wings out stretched and the top of its thorax and abdomen exposed. It will absorb solar radiation and make its body temperature rise. When it is very warm out, some butterflies will perch parallel to the sun‚s rays with their wings together and extended above their abdomen in an attempt to reduce impact of solar radiation. Stoffolano, 1998; Scott, 1986. Butterflies have an optimum temperature range of 28 38 degrees Celsius during which they are active Scott, 1986. But even within this range, specific temperatures may be better, or even essential, for particular activities Stoffolano, 1998. In the case of Anartia fatima higher temperatures appear to be better for mate finding and courtship. Temperature had significant impacts on the amount of time males spent off of their perches and also on the size of their territory, or the maximum distance they flew from one perch to another. An increase in temperature, usually meant that the male was

PAGE 9

spending more time flying Figure 2, possibly in search of females, or in many cases, chasing interlopers. As tem perature increased, males also increased the distance they flew between perches Figure 4. An increase in territory may aid the male in mate location. There was also a slight trend for an increase in wind speed to increase the number of perches a male ha d. This could be due to the fact that as wind speed increased, the male needed to perch more frequently to avoid being blown off of course or be damaged. Time of day may have had a slight impact on the number of chases a male had and also the amount of tim e spent feeding. As the day progressed from 10: 30AM to 1: 30PM males seemed to chase interlopers less frequently, but feed more often. This may be a result of a variation in the female‚s behavior in the morning versus the afternoon. Females begin oviposi tion in the midmorning DeVries, 1987. Perhaps males are chasing more in the morning so that they can find a female early on, engage in courtship behavior and hopefully copulate before the female becomes completely unreceptive in the afternoon. Then in th e afternoon, they spend time feeding while the females are ovipositioning or avoiding male encounters. This is something that could be tested by comparing the activity patterns of the females to the males. The reproductive success of an individual male Anartia fatima is most likely dependent on many factors, such as the receptiveness of females to courtship attempts, the degree of aggressiveness of the male, and ambient conditions. The age of a male may determine how he responds to each of these variable s, and therefore his reproductive success. It is not assumed that all species of aggressive butterflies are expressing such a behavior for the same reasons as A. fatima In order to determine the cause of aggressiveness within a species of butterfly, the f actors that influence its reproductive success should be considered A. priori. ACKNOWLEDGEMENTS Thank you Dr. Alan Masters for all your support and help with the methods of data collection, statistical analysis, and the logistics of the discussion. Thank you Andrew and Tim for your patience and help with making the figures for this report and answering questions. Thank you Mauricio Garcia for helping translate the abstract. Thank you to the Villalobos Ramirez family for everything. Thank you to my classma tes who somehow allowed me to monopolize on computer space during such a hectic time. LITERATURE CITED Alcock, J. 1984. Animal Behavior, An Evolutionary Approach. Sinauer Associates Inc, Sunderland, Massachusetts. DeVries, P. J. 1987. The Butterflies of Costa Rica. Princeton University Press, New Jersey. Haase, E. 1999. Foraging Duration and Defensive Behavior of Anartia fatima Nymphalinae. Tropical Ecology and Conservation, CIEE. P. 223 232 Krebs, J. R. and N.B Davies. 1978. Behavioral Ecology, An Evo lutionary Approach. Blackwell Scientific Publications, Osney Mead, Oxford. Krebs, J.R. and N.B. Davies. 1981. An Introduction to Behavioral Ecology. Blackwell Scientific Publications, Osney Mead, Oxford. Monge Najera, J., F. Hernandez, M. I. Gonzalez, J. Soley, J. Araya, and S. Zolla. 1998. Spatial

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distribution, territoriality and sound production by cryptic butterflies Harnadryas, Lepidoptera: Nymphalidae: implications for the industrial melanism" debate. Re vista De Biologa Tropical 46 2: 297 330 Price, Peter W. Insect Ecology. John Wiley & Sons, Inc., Canada. Seilberglied, R. E. 1983. Anartia fatima Cocinera, White banded Fatima. In D. Janzen Ed. Costa Rican Natural History. University of Chicago Press, Chicago Illinois, pp. 682 683. Scott, J ames A. The Butterflies of North America. Stanford University Press, Stanford California. Stoffolano J.G.; W. S. Romoser. The Science of Entomology. McGraw Hill Companies Inc., USA. Zar, Jerrold H. 1984. Biostatistical Analysis. Prentice Hall, Inc., New Jersy.


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