Territorial Fights Research Articles

The Menacing Grip of Gangs in Romeo and Juliet:A Literary Evidential Analysis

Often admired for its portrayal of young love, William Shakespeare and his “Romeo and Juliet” tragedy likewise delve into the menacing impact and theme of gang violence. This research considers how Shakespeare uses the violent clashes in the play to expose the social and family structures of his time, the renaissance, highlighting the impact of gang mentality on districts and families. Through a qualitative, historical, and literary methodological approach, the research takes a close look at the key scenes in the play, the consequences of the territorial fights, and the behavior of the characters to prove that that gang violence is behind the deaths of the protagonists. The prime discovery revealed that the feud between the Montagues and Capulets reflected and are crucial to impact both society and inner family safety. The findings suggest that Shakespeare uses gang violence as a powerful metaphor to explore how rivalries can negatively impact both unity of a community and individual destinies. This research serves in attempting to bond both classical literature and modern social concerns, relating tactics and recitals, as a novel way to view, break down, and prove the historic existence of gang violence.

Cautious individuals have non-invadable territories, according to an evolutionary mechanistic model

Territoriality is widespread in the animal kingdom, but its evolutionary origins are less understood than the movement patterns that generate it. Previous studies attempted to understand the evolution of these movement patterns by assuming that certain movement patterns comprised competing strategies and using evolutionary game theory to find which strategies would provide greater fitness and give rise to evolutionary stability. Four strategies were identified: Cautious, an individual that moves through the landscape avoiding all places where it experienced conflicts with other animals; Common-sense, an individual that avoids areas where it lost conflicts and selects areas where it won conflicts; Paradoxical, an individual that does the opposite of Common-sense; and Daring, an individual that seeks areas where it won conflicts, but is unaffected by loss. Previous models used a combination of individual-based models and algebraic calculations, but they did not incorporate recent developments in mechanistic models. Here, we developed a stochastic individual-based model using fluid dynamics to represent space use and used invasion tests to determine evolutionary stability. Using this model, we tested which (if any) of the previous strategies would be evolutionarily stable in two scenarios: one with inconclusive territorial fights and another without. We found that the cautious strategy was evolutionarily stable, in disagreement with previous literature. Cautious individuals show a more homogeneous use of space, when compared to the other three strategies. Cautious individuals tend to win most resources across the environment, which results in greater fitness than other strategies and allows it to invade populations comprised of any of the others. Daring also invades paradox and common-sense strategies, while paradox invades common sense. There was no qualitative difference between scenarios. We discuss how the evolutionary stability of this strategy depends on whether individuals employ their maximal effort when foraging.

Battle of the borders: Is a range-extending fiddler crab affecting the spatial niche of a congener species?

Climate change is drastically altering environmental conditions and resource availability. Many organisms are shifting their distribution boundaries. Fiddler crabs, for instance, are important ecosystem engineers in coastal environments that have been extending their distribution range poleward. In this study, we evaluated the influence of a range-extending species, Leptuca cumulanta, which has recently overlapped the distribution of the resident species Leptuca uruguayensis. Through a set of field and laboratory experiments, we characterised the degree of territorial overlap between L. cumulanta and L. uruguayensis from the lower to upper intertidal zone in a mangrove area. We also analysed whether the presence of L. cumulanta prevents habitat choosiness or influences agonistic behaviours in L. uruguayensis in territorial fights. We found that both species overlap territories at the same level in the intertidal zone. However, we observed that both habitat choice and agonistic behaviours of L. uruguayensis were unresponsive to the presence of L. cumulanta. The low interference between recent heterospecific neighbours sharing the same space supports coexistence of fiddler crabs L. uruguayensis and L. cumulanta in the early stage of overlapping.

Structural coloration predicts the outcome of male contests in the Amazonian damselfly Chalcopteryx scintillans (Odonata: Polythoridae)

Iridescence is an optical effect that produces angle dependent coloration in animals. Recently, studies have attempted to unveil structures behind such elaborated visual signals and associated behaviors in Odonata. Here, we studied males of the Amazonian damselfly Chalcopteryx scintillans, which have hindwings that exhibit pronounced iridescence. This optical feature is used by the damselflies for intra-specific communication during territorial fights and courtship. The main question we addressed was whether male wing structural coloration may predict the outcome of male-male contests. We also studied the wing ultrastructure, in order to reveal the mechanisms that are responsible for wing coloration. Using various microscopal and spectroscopal techniques, we demonstrate that hindwing coloration is derived from two main effects: (1) light interference in the cuticle multilayer and (2) a specific angle dependent light scattering and antireflective properties of the epicuticular wax coverage. The results of our field experiment show that wing pigmentation and the hue of the dorsal surface of the hindwings is correlated with the outcome of territorial contests. This is one of the first studies showing that structural coloration derived from multilayer interference may influence the outcome of intrasexual agonistic interactions. This indicates that multicomponent structural coloration in visually guided insects may be under selective forces of male-male competition for resources and females.

Testing the dear enemy relationship in fiddler crabs: Is there a difference between fighting conspecific and heterospecific opponents?

Reduction of aggressiveness toward familiar neighbors, when compared to aggressiveness toward unfamiliar strangers, can decrease the costs of territory defense. This phenomenon is known as the “dear enemy effect”. Individuals may shift their aggressiveness toward neighbors or strangers from the same or different species, depending on the relative threat associated with different opponents. Therefore, a reduced level of aggressiveness between heterospecific neighbors is expected in relation to conspecific intruders, since the latter compete not only for territory, but also for mates. Herein we investigated the occurrence of the dear enemy effect in territorial fights between conspecific pairs of Leptuca leptodactyla and heterospecific pairs of L. leptodactyla versus Leptuca uruguayensis. Across both conspecific and heterospecific fights, medium- and high-intensity fight components were more used in resident–stranger than in resident–neighbor fights. Thus, residents showed a dear enemy response, regardless of opponent species. Moreover, conspecific fights induced a greater number of low- and medium-intensity fight components than did fights between heterospecifics, both neighbors and strangers. Finally, conspecific resident–stranger fights took longer than heterospecific resident–stranger fights. Our results indicate that fiddler crabs adjust their territorial response according to the species and resident status of intruders, consistent with the risks posed by different intruder types.

Agonistic interactions in the dragonfly Micrathyria ungulata: does male fighting investment come from an innate ability or an indomitable will?

In fights between males for access to mating territories, the winner may be the rival with the highest fighting capacity or that places the highest value on the disputed site. However, it is also possible that both factors simultaneously affect dispute settlement. Therefore, a better understanding of contest resolution rules may be achieved by simultaneously investigating how winning chances depend on individual motivation linked to resource value and on individual traits linked to fighting capacity. In this study, we used males of the dragonfly Micrathyria ungulata to evaluate whether individual fighting ability, individual motivation, or the interaction between both factors determine the individual investment in territorial contests. For this, we simulated the approach of an intruder to trigger a territorial defense response by either resident (marked males present in the territory for at least 1 day before the experiment) or substitute males (marked males that occupied the territories after we removed the residents). Resident males fought longer against the potential intruder than their substitute counterparts. However, traits related to fighting ability had a marginal effect on the time invested in fights. These results indicate that resident males are more willing to invest in fights regardless of their physical or physiological attributes. Distinct motivational levels among individuals should increase the variation in mean contest duration among rival pairs. If this effect is widespread, it may have important implications for studies that investigate contest rules by relating fighting duration and individual traits. In many species, the winner of territorial fights is the individual with higher fighting ability or the one that values more the disputed resource and consequently is more motivated to fight. However, because these two factors may interact to determine the winner, investigations should benefit by simultaneously evaluating the effect of fighting ability and motivation on contest resolution. Here, we induced fights between focal males against artificially introduced rivals to test if male investment in fights is affected by an interaction between traits linked to fighting ability and motivational status. We showed that the prior occupation of a territory was the main determinant of the time spent fighting. We conclude that the previous occupation of a territory may increase individual motivation to fight due to higher valuation of the resource and eventually may surpass the effect of fighting ability to determine the winner.

Territory Availability at Different Spatial Scales does not Affect Fighting Investment in Males of the Lycaenid Butterfly Strymon mulucha

AbstractIn territorial species, rivals investment in fights over territories may increase when the availability of suitable areas for defense is low. This should occur because low territory availability may increase the costs to maintain and acquire territories. Although such process occurs in small spatial scales (local scale), territory availability in larger scales (regional scale) may also affect fighting investment, as losers should incur additional dispersing costs to find new territories. In this study, we used males of the hilltopping butterfly Strymon mulucha to evaluate the hypothesis that males should invest more in territorial fights when the costs to find new territories are higher (both at local and at regional scale). We timed male–male contests for territories located in 12 hilltops and measured male density per territory in each hilltop (local scale). We also quantified the distance between hilltops containing suitable areas for territories (regional scale). Male–male contests lasted 21 s on average, and copulations did not occur during the observations. The duration of contests was unrelated to the male density per territory or to the distance among hilltops, indicating that the investment in fights was unaffected by the availability of territorial sites, independent of the spatial scale. As male–male contests in S. mulucha are longer than the mean contest duration in other butterfly species and mating is extremely rare, we suggest that the value of each territory may be high enough to favor males that always invest as much as possible in contests.

Pax by Sara Pennypacker (review)

Reviewed by: Pax by Sara Pennypacker Kate Quealy-Gainer, Assistant Editor Pennypacker, Sara Pax; illus. by Jon Klassen. Balzer + Bray/HarperCollins, 2016 [304p] Trade ed. ISBN 978-0-06-237701-2 $16.99 E-book ed. ISBN 978-0-06-237703-6 $11.99 Reviewed from galleys R Gr. 4-7 “War is coming. It means sacrifices for everyone.” So says Peter’s father as he leaves to serve and sends Peter to live with his grandfather three hundred miles away, which means Peter must release back into the wild Pax, the fox he has been caring for five years. Peter doesn’t even last one night at his grandfather’s house before he gathers up supplies and heads homeward to find his fox; meanwhile, Pax is forced deeper into the forest by army traffic. Separated by miles, the friends embark on two very different journeys that eventually bring them together, just not in the way they expected. The focalization alternates between Peter and the fox, giving readers a sense of the depth of their connection and particularly Peter’s need for reunion; afraid that he will inherit his father’s bouts of anger and violence, Peter hopes that nurturing Pax will prevent that fate. The narration that follows Pax has a simplicity that still manages to be strikingly emotional, while Peter’s chapters are more layered, with painful secrets revealed at a steady but organic pace. Pennypacker doesn’t romanticize her animal world, with believable territorial fights happening among the wildlife; ultimately, though, the book is an indictment of war, notable in the depiction of the soldiers reveling in destruction and through the character [End Page 322] of Vola, an ex-medic who cares for Peter when he breaks his foot. The ending is a classic tearjerker, and even readers who predict it will still find themselves reaching for a tissue. Copyright © 2016 The Board of Trustees of the University of Illinois

Spoils of war and peace: enemy adoption and queen-right colony fusion follow costly intraspecific conflict in acacia ants

Lay Summary Territorial fights between acacia ant colonies can alter their genetic composition via 2 processes: victorious colonies adopt former enemies or colonies fuse. Acacia ant colonies engage in lethal contests for resources, in which even eventual victors suffer heavy casualties. After fights, victorious colonies with diminished workforces are less able to defend vital resources. Costs of fighting appear to be offset, and recovery from conflict hastened, by the inclusion of nonrelatives into colonies.

Mechanism of the wing colouration in the dragonfly Zenithoptera lanei (Odonata: Libellulidae) and its role in intraspecific communication

Zenithoptera dragonflies are known for their remarkable bluish colouration on their wings and unique male behaviour of folding and unfolding their wings while perching. However, nothing is known about the optical properties of such colouration and its structural and functional background. In this paper, we aimed to study the relationship between the wing membrane ultrastructure, surface microstructure and colour spectra of male wings in Zenithoptera lanei and test the hypothesis that colouration functions as a signal in territorial fights between males. The results show that the specific wing colouration derives from interference in alternating layers of melanized and unmelanized cuticle in the wing membrane, combined with diffuse scattering in two different layers of wax crystals on the dorsal wing surface, one lower layer of long filaments, and one upper layer of leaf-shaped crystals. The results also show that the thicker wax coverage of the dorsal surface of the wings results in increased brightness and reduced chroma. In the field experiments, we have demonstrated that there is a reduction of aggressive reactions of rivals towards individuals with experimentally reduced amount of blue wing colouration.

Seasonal polyphenism in wing coloration affects species recognition in rubyspot damselflies (Hetaerina spp.).

Understanding how phenotypic plasticity evolves and in turn affects the course of evolution is a major challenge in modern biology. By definition, biological species are reproductively isolated, but many animals fail to distinguish between conspecifics and closely related heterospecifics. In some cases, phenotypic plasticity may interfere with species recognition. Here, we document a seasonal polyphenism in the degree of dark wing pigmentation in smoky rubyspot damselflies (Hetaerina titia) - a shift so pronounced that it led early researchers to classify different forms of H.titia as separate species. We further show how the seasonal colour shift impacts species recognition with the sympatric congener Hetaerina occisa. Interspecific aggression (territorial fights) and reproductive interference (mating attempts) are much more frequent early in the year, when H.titia more closely resembles H.occisa, compared to later in the year when the dark phase of H.titia predominates. Using wing colour manipulations of tethered damselflies, we show that the seasonal changes in interspecific interactions are caused not only by the seasonal colour shift but also by shifts in discriminatory behaviour in both species. We also experimentally tested and rejected the hypothesis that learning underlies the behavioural shifts in H.occisa. An alternative hypothesis, which remains to be tested, is that the seasonal polyphenism in H.titia wing coloration has resulted in the evolution of a corresponding seasonal polyphenism in species recognition in H.occisa. This study illustrates one of the many possible ways that plasticity in species recognition cues may influence the evolution of interspecific interactions.

Há diferenças que fazem diferença? Lutas identitárias e conflitos ambientais nas dinâmicas de expansão capitalista da Amazônia

In a context of territorial disputes, the politicization of identity has represented a way of supporting the peasant populations and traditional communities to stay in their place. The culture as a resource and the resource to the culture has been use as strategies of mobilization to obstruct the dynamics of expropriation that affect these population in so far as the economical fronts advance on the new territories. To try to account for this tangle universe that plasma at the junction between culture, territorial fights, socio-legal recognition and environmental preservation, the article is anchored in fields works conducted in the western region of Para, which over the last decade has been locus of intense conflicts of lands involving new areas of capitalist accumulation and traditional populations, indigenous and peasant populations. From the data collected in the works fields, it will aim to demonstrate how the use of culture in association with the politicization of differences has been tacked by territorial belonging to guarantee the permanence of traditional people in their ancestral places occupied. Then, the article analyzes the decision of the Supreme Court in the judicial case which challenges the continuous demarcation of the Raposa Serra do Sol. This case is paradigmatic to understand the speeches and arguments delivered by the Brazilian main Court regarding the recognition of cultural and territorial rights. The data and analysis collated here, it will aim to demonstrate how the use of culture in association with the politicization of the differences has been brought to guarantee the permanence of traditional people in their ancestral places. Nevertheless, the judiciary, when faced with universalizing categories, as a nation, territory and sovereignty, has operated a particularization of the rights of traditional communities, turning them into a kind of public interest in the second category. Keywords: cultural identity, ethnic recognition, legalization of difference.

Multiple routes to reduced interspecific territorial fighting in Hetaerina damselflies

Multiple routes to reduced interspecific territorial fighting in Hetaerina damselflies

Conditional male dimorphism and alternative reproductive tactics in a Neotropical arachnid (Opiliones)

In arthropods, most cases of morphological dimorphism within males are the result of a conditional evolutionarily stable strategy (ESS) with status-dependent tactics. In conditionally male-dimorphic species, the status’ distributions of male morphs often overlap, and the environmentally cued threshold model (ET) states that the degree of overlap depends on the genetic variation in the distribution of the switchpoints that determine which morph is expressed in each value of status. Here we describe male dimorphism and alternative mating behaviors in the harvestman Serracutisoma proximum. Majors express elongated second legs and use them in territorial fights; minors possess short second legs and do not fight, but rather sneak into majors’ territories and copulate with egg-guarding females. The static allometry of second legs reveals that major phenotype expression depends on body size (status), and that the switchpoint underlying the dimorphism presents a large amount of genetic variation in the population, which probably results from weak selective pressure on this trait. With a mark-recapture study, we show that major phenotype expression does not result in survival costs, which is consistent with our hypothesis that there is weak selection on the switchpoint. Finally, we demonstrate that switchpoint is independent of status distribution. In conclusion, our data support the ET model prediction that the genetic correlation between status and switchpoint is low, allowing the status distribution to evolve or to fluctuate seasonally, without any effect on the position of the mean switchpoint.

Perceived predation risk and mate defense jointly alter the outcome of territorial fights

Virtually all animal conflicts occur over access to mates or resources that affect survival, the two key components of fitness. In this paper, we report that predation risk and mate defense jointly affect the outcomes of contests between male sand crabs (Scopimera globosa) for burrows in which crabs mate and take shelter from predators. We observed the contests under three different conditions: (1) the natural condition of low predation risk and without the presence of a female; (2) the first experiment in which we imposed upon only intruding males the perception of predation risk—by digging them from their burrows, capturing and handling them, and placing them into other males’ burrows—to increase the value of the burrows for the intruders as shelter, and (3) the second experiment in which we repeated this treatment but increased the resource value of the burrow to the resident by placing a female in his burrow. The difference in body size between contestants was the main determinant of victory in all analyses. However, perceived predation risk also partly affected the outcomes of the fights: The motivated intruders were likely to win even when they were a little smaller than the residents. In addition, defense of a female had a significant effect on the outcomes of fights: The motivated residents won more fights than the motivated intruders, indicating that these two treatments caused asymmetric increases of the resource value. This is the first report of two external factors simultaneously raising resource value, affecting motivation of contestants, and altering the outcome of fights.

Recovery dynamics and viability of the white-tailed eagle (Haliaeetus albicilla) in Germany

Understanding the effect of protection measures on recovery of endangered populations is crucial for assessing the efficiency of management plans. Following the ban of DDT, PCB and other detrimental chemicals in the 1970s, the German white-tailed eagle population recovered rapidly. Using nest monitoring data, dead recovery data and population dynamics models, we examined both short and long-term viabilities of the population. Between 1991 and 2005 the proportion of breeding pairs with an active nest among territorial pairs was α = 0.88 ± 0.007. Annual breeding success was γ = 0.62 ± 0.014. Mean fledged brood size was b = 1.50 ± 0.010 fledged/successful breeding pair. The analysis of dead recovery data of 1,273 individuals ringed as nestling between 1991 and 2006 allowed survival rates to be estimated. We needed to distinguish between “young” (5 years old) and “old” (older than 5 years) adults. Furthermore the annual survival rate was higher for juvenile and immature birds (0.921 ± 0.024) than for adults (s“young” = 0.760 ± 0.097 and s“old” = 0.875 ± 0.079), a pattern presumably explained by territorial fights. Finally, an age structured model was used to examine the joint effect of population regulation, environmental and demographic stochasticities. All results indicated that only pessimistic scenarios could lead to substantial extinction probabilities within 100 years. We conclude that management measures were successful in removing the main extinction factors of the population and that future conservation efforts need to focus on the remaining ultimate extinction causes.

Lek behavior in hypercephalic Zygothrica dispar Wiedemann (Diptera, Drosophilidae)

In the Neotropical drosophilid secies Zygothrica dispar the males, many of which are hypercehalic, engage in territorial fights on mushrooms. In an attempt to see whether head width effects mating success, lek behavior was videorecorded. Most owners of a territory on the cap of a mushroom are broad-headed, and usually defeat intruders, which in general have a narrower head. Escalation in confrontation to bodily contact is rare and mostly involves opponents of equal head width. Most contests between unequals end after a close head-to-head confrontation, and are thus purely ritual. Females appeared to be courted only on the lek. Although no female was observed to copulate, it can be supposed that male head width influences fitness through its effect on owning a territory on the lek.

Group Territoriality as a Form of Cooperative Breeding in the Flightless Kagu (Rhynochetos jubatus) of New Caledonia

ABSTRACT. Birds that live in family groups and cooperatively defend the family's territory are currently recognized as cooperative breeders only if helpers assist with chick rearing. We observed breeding Kagus (Rhynochetos jubatus) and video-monitored nests to determine whether help with feeding or family size affected their reproductive success. During >5,500 h of nest monitoring, helpers never provided parents or chicks with food. The reproductive success of families increased with group size nonetheless. Family size affected breeding success more than habitat-related parameters. Nonbreeding Kagus reacted to playback calls as often as breeding birds did. Observations of territorial fights gave additional evidence that nonbreeding group members help defend the family's territory and can, therefore, improve reproductive success. Our results suggest that cooperative territory-defense was the most important factor that increased the breeding success of Kagus. We propose that group territoriality should be c...

Increased risk and benefit simultaneously alter the outcome of territorial fights

AbstractCompetition for resource, including territories is seen in a broad range of taxa. There has been much research on factors that determine the intensity and outcome of competitions (e.g. resource holding potentials: RHP, and resource value: RV). No research, however, has shown how different factors can simultaneously alter the intensity and outcome of contests. We investigated the effects of RV on fighting behavior and success in inter-tidal, territorial male crabs. Under natural conditions the larger rival won contests irrespective of whether he was the resident or intruder (i.e. there was no residency effect). We then motivated intruders to fight hard by subjecting them to the threat of predation, and found that they were more likely to win contests. When we also motivated residents to fight hard by placing a female in his burrow (i.e. both rivals were simultaneously motivated to fight due to the perceived increase in resource value), we found that the contests escalated more and that resident males had a slightly increased chance of winning. This is the first report of two factors simultaneously affecting motivation and therefore altering the escalation and outcome of a contest.

Sexual size dimorphism in the American rubyspot: male body size predicts male competition and mating success

Sexual differences in body size are widespread among animals, and various explanations for the evolution and maintenance of sexual size dimorphism have been proposed. We investigated the effects of sexual selection and fecundity selection on the sizes of males and females, respectively, in American rubyspots, Hetaerina americana. Males are larger than females and have large red spots at the base of each wing that are sexually selected via male-male contests. Mating success is determined by the ownership of a territory. Large males held territories for longer and sustained longer territorial fights than small males. Territorial males obtained more copulations than nonterritorial ones. Large males also had more wing pigmentation and mated with large females. Large territorial males had high energy reserves, whereas nonterritorial males appeared to have depleted reserves. Selection analyses of body size showed disruptive selection acting on male body size, suggesting that both small and large males may be favoured in terms of mating success. We also tested whether fecundity selection acts on female size. However, female body size was unrelated to the number of eggs carried. Taken together, our results suggest that in this territorial damselfly species male-biased size dimorphism is driven by large male size in male-male competition being selectively advantageous in territory acquisition and/or maintenance. We also suggest that small size is advantageous in nonterritorial males to improve their agility in courting (or subduing) females.