Territorial Behavior of Odonata

	Picture 1 : At 5:48PM finally after hours of waiting at his territory, this male Orthetrum testaceum  (red at left) captured a female. This female Orthetrum testaceum came from no where and appeared so fast that eyes are too slow to catch how they joint.
	Picture 2 : This pair of Orthetrum testaceum copulated for 5 minutes, long enough for most photographers  to snap a few close up images. See exactly where the male dragonfly holds the female --- the upper neck behind the eyes.
	Picture 3 : At 5:53PM, after about 5 minutes of joining, the two break apart. The female immediately proceed to the water without taking a short rest like some other species. While the female ovipositing, this male maintain about 6 inches above the female. Normally a male maintain 1 or 2 meters near by. This unusual near distance is immediately understood when seeing few other equally aggressive males are just few meters away. Every few seconds, a nearby male would dart into the ovipositing female and this male would fight him off.
	Picture 4 : At 5:54PM A new behavior about Orthetrum testaceum not mentioned before.... .... a second female appeared  and with a ‘Clippppp’ sound, the male is joined with this second female. But this time instead of finding a plant to hold on, this pair prefer to copulate in the air………..just few inches above the first ovipositing female (see photo) This "faithful and responsible" male Orthetrum testaceum protecting the first female from other male,  while carrying out duty on a second female.
	Picture 5 : This  second joining in the air  is only 1 minute while the first joining (Picture 1) on land is 5 minutes. Perhaps unable to spare too long for having the first female to take care. Now two female are ovipositing and this male has two females to protect from several other males looking fiercely for a chance.
	Picture 6 : At 5:55PM The first female completed her oviposting and fly off and disappeared into near by bush leaving this second female continue ovipositing. This male Orthetrum testaceum (Burmeister, 1839) continue to maintain an unusual close distance of 6 inches above the second female to guard her from a few other males near. A moment later this second female completed ovipositing and also flew off into the bush leaving the male alone to guard his territory.

At this point, the primary goal of the dragonfly or damselfly is to find a mate. With their keen 
eyesight, the adult begins to search for prey and mates. Searching for food does not occur in the territories, 
however if prey enters the territory, the Odonata will feed (Clausnitzer, 1996). A high variation of flight 
habits exist within the insect order.  Many Odonata will perch at one site whereas others may remain in flight 
while looking for both prey and mates.  The subject of interest involves the Odonata species that remain at one 
site, often patrolling the area for mating opportunities and exclusion of male conspecifics.   This territorial 
behavior increases reproductive fitness (Hilton, 1984; Alcock, 1987).  Within the order, a variety of 
territorial behaviors exist ranging from residency and intolerance of conspecific males to aggressive behavior  
without a strong site attachment (Van Buskirk, 1986).

	Resource defense polygyny involves the intraspecific male competition to control the sites attractive 
to the adult female (Alcock, 1987;1990;Conrad and Pritchard, 1992).   If the female is attracted to a species 
specific oviposition site, successful establishment of  resource defense polygyny within the species is likely.  
In this mating system, the areas that are monopolized by the male Odonata are the oviposition sites of the 
female.  The males are found at these sites before the first female arrives to mate.  The exhibition of a  
protandrous system allows time to establish the ownership of territories.  Of the insect order Odonata, 
resource defense polygyny offers many species enhanced male mating success.  Resource defense polygyny 
results in the territorial behavior of oviposition sites as the males compete to monopolize these resources to 
increase their chances of mating with a female.  In the  insect order, the adult female oviposits after mating in 
the water, usually near or in  patches of vegetation.  Different oviposition resources are monopolized by 
different species.  In several studies, males of a species are seen to be defending territories that are suitable 
to their female conspecifics.  In the morning , the adult male is first to arrive at the mating site.  Since the 
male can mate several times, it is to its advantage to locate itself in an area where many females will be found.  
In this case, near the oviposition sites.  Since there are a limited amount of suitable oviposition sites around a 
pond or stream, competition for the sites exist among the males.  

Territorial Behavior	

	After a male Odonata has established a territory, several other males will enter the site hoping to find 
a receptive female near the oviposition site.  The owner of a territory may perch on vegetation or patrol the 
territory in search of mating opportunities.  However, several other male Odonates do not claim a territory 
because resources are limited.  These Odonates are often referred to as "roamers" or "flyers" (Sandell and 
Liberg, 1992).  Once these males enter the territory of another male, several types of territorial behaviors 
may be displayed.  In a dragonfly species, Leucorrhinia hudsonica, the territory owner seems to have the 
ability to recognize conspecific males and males of other species(Hilton, 1984).  The territorial male will leave 
his perch to chase away conspecific males, but will not pursue a chase if the male Odonate is not of the same 
species.  The male territory owner will flutter its wings in a warning to the intruder.  These wing warnings are 
common in the territorial species of Zygoptera.   If the intruder (conspecific male) has entered the boundaries 
of the territory, the territory-owner will pursue a chase flight.  A chase flight may involve clashes of the two 
insects.  These clashes were very brief lasting only a few seconds, but the attacks were directed toward the 
abdomen of the chased male from the male pursuing the chase.  The chase may be a rapid twisting entanglement 
where the clashes involve grappling of legs and mouthparts or one male be fleeing the territory.   The winner 
returns to the territory and perches, waiting for the arrival of a receptive female.   In several damselfly 
species of the families Coenagrionidae and Lestidae, a similar signal is employed to advertise ownership of a 
territory.  Termed as "wing clapping," the damselfly moves forward keeping the meso- and metathoracic wings 
together during the movement.  The damselfly then returns to its resting position (Hilton, 1984).

	In the family Chlorocyphidae, several species were studied extensively to review their territorial 
behavior (Orr, 1996).  A high amount of intraspecific variation of the territorial behavior was confirmed.  
Libellago aurantiaca establish territories that range from 1.5 to 3 meters in diameter.  Upon encountering an 
intruder, the two males face the other and make forward movements without contact.  In the dispute, the 
abdomens are held horizontally while the forewings are held forward.  Often one male will hold the forewings 
stationary for a brief second so as to display the dark apical spot.  As a result, the other male will often flee 
the territory.  Libelluga stictica defends a territory from an intruding male in a similar manner where the pair 
faces each other and then rises vertically rapidly.  The stationary wing display and forward lunges are also 
involved in the territorial dispute until one male flees the area.  Libelluga semiopaca contests for territories 
are more time consuming than those disputes of both L. aurantiaca and L. stictica lasting a mean time of 4.7 
minutes. Once again the males face each other and hover rather than move vertically during the territorial 
dispute.  The pair rotates horizontally 90 degrees and offer a series of stationary wing displays until a winner 
is decided.  Rhinoneura villosipes settle territorial disputes in a similar manner to that of L. semiopaca. The 
stationary wing display involves the hindwings rather than the forewings to offer the opponent a view of the 
dark apical mark.  Rhinocypha aurofulgens employs the stationary wing display while ascending rapidly and 
displaying the abdomen by bending it upward.  Once the pair has ascended approximately 1 to 2 meters, they 
descend and reengage or the loser is chased out of the territory by the victor.  Rhinocypha humeralis do not 
employ the stationary wing display, but rather make a series of darts  toward the opponent while rotating 
slightly in the horizontal plane.  

	Of the many displays of territorial behavior, variation exists to a large degree possibly due to several 
factors such as larval ecology, residency, time of day, weather conditions, age and size of the dragonfly or 
damselfly.  Several behaviors of the territoriality have been described, but what determines the winner of a 
territorial dispute?  Several factors have been shown to sway the outcome of a territorial contest of two 
males. The relationships between these many variables are still unknown and many have been shown to be 
contradictory.

Time of Day/Weather

	As true with most insects, the temperature regulated the activity of the Odonata.  Temperatures below 
25 degrees Celsius slowed the activity whereas an optimal temperature above 30 degrees Celsius increased  
activity (Jacobs, 1955).  Also, weather conditions greatly affected the activity of the Odonata (Hilton, 1984).  
On warm sunny days, flight activity increased, therefore increasing the number of intraspecific interactions.  
During overcast weather conditions, males were not located at the oviposition sites. The time spent at 
oviposition sites varies for male and female Odonata.  The males arrive as early as 9 am and leave as late as 6 
PM depending on the species.  The females arrive several hours later after the males have established 
territorial possession of the oviposition sites (Campanella, 1975).  In a study of  Brechmorhoga pertinax, the 
male arrives at the oviposition sites around 9:30 am and activity decreases around 2:30 PM.  Throughout the 
day, male activity is correlated with the presence of females which is at an optimum between 12:30 and 1 PM.  
The males exhibit the highest patrolling activity of  their territory during this time (Alcock, 1987).    Both the 
time of day and weather conditions serve as parameters for evaluating territorial behavior. 

Larval Ecology

	The larvae of Odonata have shown feeding territoriality in laboratory experiments.  The success of 
larvae in feeding territoriality has been shown to positively influence the reproductive success of the adult 
male(Harvey and Corbet, 1985).  Since a larger adult size is advantageous to reproductive success, a larvae 
that has reached a larger size by the final-instar larvae would enhance its reproductive fitness.   Food 
availability has little effect on the survival of Odonata larvae, it may, however affect the size of the instar at 
the final molt. In a study of Pyrrhosoma nymphula larvae, the last three or four instars were supplied with low 
and high amounts of food to determine the effect of food availability on adult size.  Food availability was found 
to be positively correlated with the body length of the Odonata.

Size
	 
	In turn, the consequences of territorial behavior on the larval ecology of a damselfly were studied in 
relation to the adult size of  Megaloprepus coerulatus (Fincke, 1992).  Since larger males win more territorial 
contests, his chances of defending a desirable oviposition site are greater.  Also, it is suggested that larger 
males exhibit greater success of defending larger territories that are highly desirable to female conspecifics.  
In the Megaloprepus coerulatus,  the female oviposits in tree holes.  Larger tree holes are desirable oviposition 
sites because they can  support a greater number of offspring.   Therefore, larger males that can retain a large 
tree hole as its territory is increasing its reproductive fitness in terms of the number and quality of offspring.
	
	Several studies have shown the larger size of the adult male to be advantageous to the reproductive 
fitness of the Odonata (Fraser and Herman, 1993;Marden and Waage, 1990; Tsubaki and Ono, 1987).  Despite 
this fact, variation persists in the insect order.  In a study of Libellula quadrimaculata, the larger males were 
demonstrated to be at a disadvantage as a result of their size (Convey, 1989).  The larger males had a lower 
proportion of muscle mass relative to the rest of their body and therefore, were determined to have a lower 
level of maneuverability when compared to smaller males.  Apparently,  due to their larger size, the power 
output is lower than that of smaller males and therefore, larger males can not accelerate as rapidly as smaller 
males. As a result, the larger males were unable to retain territories and resorted to satellite (roaming) 
behavior as other smaller males of other species.
	
Age

	In the Nannothemis bella,  a Libellulid dragonfly, the date of emergence affects the ability of the male to 
retain territories (Lee and McGinn, 1986).    A late emergence date reduces the ability of the dragonfly to hold 
a territory and therefore may affect the reproductive fitness.  The dragonfly that emerged later  than the 
majority of its conspecifics has less time to reproduce in that season.  In addition, the territories have already 
reached levels where a high amount of competition exists for the males.  

	The age of a dragonfly or damselfly affects the ability to obtain or retain a desirable oviposition site 
(Tsubaki and Ono, 1987).  Younger males won more territorial disputes suggesting that age may be more of a 
component in determining the victor of a territorial contest.  In addition, Calopteryx maculata males that have 
been adults for longer than 20 days represented a low proportion of the males possessing territories (Forsyth 
and Montgomerie, 1987).  The low number of older males retaining a territory is due to displacement by 
younger males 5 to 20 days into their reproductive adult stage. In a comparison of winners and losers of 
territorial contests, the group of winners were significantly younger than the group of losers. male mating 
success and territorial possession decrease with age.  

Residency

	Residency of a territorial site has been suggested to increase the male's ability to win a territorial 
contest.  Territorial contests between residents and intruders were evaluated to determine if residents did 
indeed have an advantage in the dispute (Gribbin and Thompson, 1991). The mean masses of the territory 
residents and intruders were shown to have no significant difference.  Ruling out size as a determining factor of 
a victory, the residents were suggested to possess an advantage in a territorial contest.  In this study of the 
damselfly Pyrrhosoma nymphula, the residency asymmetry was determined to settle the territorial disputes.    

	In a study of the damselfly Calopteryx maculata, the territorial disputes between males of adjacent 
territories were evaluated (Waage, 1988).  Two males may become residents of one territory or two 
overlapping territories.  The resident male patrols his territory and may not see the intruder before he has 
established the territory as his own.  The intensity and duration of these disputes were greater than a normal 
resident/intruder bout suggesting that the advantages offered by residency were canceled out.  This suggests 
that residency may offer both an advantage and a disadvantage to the resident.  The duration of bouts between 
the adjacent residents escalated,  lasting longer and therefore expending more energy.  


Final Comments

	Territorial behavior exhibited by the Odonata vary greatly in many aspects among species (Hilton, 
1984; Orr, 1996).  Many different behaviors have evolved to optimize the number of opportunities to 
successfully reproduce with females.   The parameters that affect territorial behavior and the outcome of the 
territorial contests vary to a high extent.  Several different components are involved with odonate territorial 
behavior, specifically, larval ecology, previous residency, time of day, weather, size and age have been shown 
to influence territory possession (Fincke, 1992; Harvey and Corbet, 1992; Tsubaki and Ono, 1987; Gribbin and 
Thompson, 1991).  Of these components, larval ecology determined the size of the adult male (Harvey and 
Corbet, 1985).  The larger size of the adult male offered the Odonate an advantage to retain desirable 
territories and therefore, was concluded to increase reproductive fitness (Fincke, 1992; Fraser and Herman, 
1993;Marden and Waage, 1990; Tsubaki and Ono, 1987).    In another species, a large body size was shown to 
negatively correlate with reproductive fitness, leaving this character unreliable as to determining the outcome 
of territorial disputes ( Convey, 1989).  In addition, Gribbin and Thompson determined that the body mass of 
Pyrrhosoma nymphul offered no advantages or disadvantages to the territorial males (Gribbin and Thompson, 
1991).  A determining characteristic of a victor of a territorial contest involved the age of the adult male.  In 
these studies, the younger males appeared to have an advantage of retaining a territory.  As a result, 
generalizations of territorial behavior across the order are difficult to apply. Overall , determining 
characteristics of a winning territorial male Odonate vary greatly among species. Until further research 
determines a reliable winning character or behavior, each species' territorial behavior must be studied 
individually.   

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INDEX OF DRAGONFLY