Predator Avoidance Research Paper Example

Introduction

Predation is a biological association between two organisms where one organism (the predator) feeds on another organism (the prey). In this interaction, the predator may either kill the prey or not before feeding on it. However, in most cases, predation results in the death of the prey and its eventual consumption by the predator. In predation, there is transfer of energy from one organism (the predator) to another (the prey) and also from a lower trophic level to a higher one.

COMPARISON OF ANTI-PREDATOR MECHANISMS IN GAZELLES AND ANTELOPES

Not only do gazelles and antelopes inhabit the same ecosystems and the same trophic level but also have common predators. Some of these predators include lions, cheetahs, hyenas, and wild dogs. As such, they have developed similar mechanisms to avoid these predators. The mechanisms include grouping, vigilance, monitoring, and flight.

Grouping

Grouping refers to an instance where animals to congregate in large numbers (FitzGibbon and John 277). This phenomenon is seen in both antelopes and gazelles. It reduces the risk of an individual being eaten by predators. This is known as dilution effect (Delm 337). The group members at the periphery of the group are at a higher risk as compared to those at the centre.
Another way in which grouping assist is by group members using the information obtained by a member on the presence of a predator to respond. In gazelles and antelopes, the information usually come in form of tail-flagging (Beauchamp 241) which alerts other group members of the presence of a predator.
Moreover, studies have found that the chances of the predator catching the prey reduces as the prey numbers increase. Grouping leads to predator confusion as large numbers of prey makes the predator confused on a particular individual of the group to focus on.

Vigilance

This refers to the act of being aware of environmental of the dangers in the immediate environment of a particular animal or group of animals. Vigilance in gazelles and antelopes helps to detect predators which are at long distances. This will then give the herbivores good time to escape. It is done by all members of a particular species which then convey the message to other members concerning and impending danger. This mechanism is important as it allows the animals to respond quickly to the presence of the predator and thus reduces the chances of being eaten (Mills and Jeremy 631).
Studies have found out that vigilance is higher in areas of higher predation and also in presence of young members of a population (Hunter and Skinner 200). Furthermore, vigilance has been reported to decrease with the herd size (Hunter and Skinner 201). Some of the factors which influence the level of vigilance include body size, distance from members of related species, and location of the animal within the group (Mills and Jeremy 631).

Monitoring

This phenomenon describes the act of keenly watching the movements of the predator as well as its intentions so as to avoid surprise attacks. Monitoring is done till the prey is certain that the predator is no longer a threat. Generally, older herbivores tend to monitor a predator for a longer time as compared to their younger counterparts. It has also been noted that the time the mother prey monitors the predator decreases as the age of the offspring increases (FitzGibbon and John 281).

Flight

Flight as an antipredator approach is shown both in antelopes and gazelles (Estes 120). When the predator approaches, the prey resort to fleeing so as to avoid capture. The success of escape is determined by the speed of the prey, the reaction time, the distance of flight, and the length of time high speed can be maintained (FitzGibbon and John 282).

PREDATOR AVOIDANCE IN DIFFERENT SPIDER SPECIES

Salticids and hummingbirds are some of the common predators of spiders. A look at predator avoidance mechanisms of four different spider species reveals similarities and differences in their approach to evading the same predator. The four spider species include Argiope argentata, Nephila clavipes, Cyclosa caroli, and Uloborus republicanus.

Behavioural response to Salticids (Phiale guttata)

In a study carried out by Hoffmaster (70) on predator avoidance behaviours of different spider species, it was revealed that Argiope argentata employed jumping as one of the mechanisms to avoid Salticids (predator). Other mechanisms included rapid lateral movements as a response to posterior body touch. On the other hand, pumping and stilting was a behavioural response to ventral contacts.
In the same study, Nephila clavipes was found to share some predator avoidance mechanisms with Argiope argentata. For instance, dorsal body contact in N. clavipes resulted in rapid lateral movements. However, N. clavipes employed jumping in 100% of the responses to dorsal body contact whereas A. argentata used the mechanism in 72% of the responses to dorsal body touch. Just like A. argentata, N. clavipes also utilized pumping and stilting behaviours to avoid predators (Hoffmaster 70).
In the case of Cyclosa caroli, lateral movements as well as pumping accounted for 75% of the predator contact on the spider. The other mechanisms that the species use to deter the predator included drops and attacks (Hoffmaster 71) which comprised of 25% of the responses.
Just like the other spider species, Uloborus republicanus responded to salticid contacts by rapid lateral movement which accounted for (69%) of antipredator responses. Another interesting finding was that Uloboroids which had egg masses moved the eggs away from the predator as they escaped. They did not drop as this would have resulted in loss of the eggs. However, those without egg masses did drop so as to avoid being eaten. This antipredator behaviour accounted for 20% for those without eggs (Hoffmaster 70).

CONCLUSION

Predators have an impact on the life chances and continuity of a particular species of organisms. Some of the impacts include reduction in population and decrease in reproduction rates. As such, organisms have developed mechanisms of avoiding the predators. Some of the mechanisms in antelopes and gazelles include grouping, flight, monitoring, and vigilance. On the other hand, spiders show different antipredation mechanisms depending on the species. However, the common antipredatory behaviours include rapid lateral movements and jumping.

Work cited

Beauchamp, Guy. Social Predation How Group Living Benefits Predators and Prey. London, UK: Elsevier Science, 2013. Print.
Delm, Michael M. "Vigilance for predators: detection and dilution effects."Behavioral Ecology and Sociobiology 26.5 (1990): 337-342.
Estes, Richard. The Behavior Guide to African Mammals: Including Hoofed Mammals, Carnivores, Primates. Berkeley: U of California, 1991. Print.
FitzGibbon, Clare D., and John Lazarus. "Antipredator behaviour of Serengeti ungulates: individual differences and population consequences." Serengeti II: Dynamics, management, and conservation of an ecosystem 2 (1995): 274.
Hoffmaster, Debra K. "Predator avoidance behaviours of five species of Panamanian orb-weaving spiders (Araneae; Araneidae, Uloboridae)." Journal of Arachnology (1982): 69-73.
Hunter, Luke TB, and J. D. Skinner. "Vigilance behaviour in African ungulates: the role of predation pressure." Behaviour 135.2 (1998): 195-211.
Mills, D. S., and Jeremy N. Marchant-Forde. The Encyclopedia of Applied Animal Behaviour and Welfare. Wallingford, UK: CABI, 2010. Print.