Symbiotic relationship between oxpeckers and rhinoceroses evolution

Rhinos & the Oxpecker Bird | Animals -

symbiotic relationship between oxpeckers and rhinoceroses evolution

The term mutualism refers to a relationship in biology between two living things who are mutually beneficial to each other. Oxpeckers and zebras or rhinos - In this relationship, the oxpecker (a bird) lives on the Examples of Macroevolution . The adorable oxpecker, perched on the back of a rhinoceros or zebra, in the journal Evolution, that the oxpecker can also be viewed as a parasite to their “ These results support the hypothesis that the relationship between species believed they were a perfect example of mutualistic behavior, where. One example of a mutualistic relationship is that of the oxpecker (a kind of bird) and the rhinoceros or zebra. Oxpeckers land on rhinos or zebras and eat ticks and other parasites that Organisms in a mutualistic relationship evolved together.

Red-billed Oxpeckers appear to be limited to medium and small-sized ungulates, such as Kudu and Impala, in the northern parts of KNP. This is most likely because of a home range overlap with Yellow-billed Oxpeckers, resulting in interspecific competition Koenig The larger in terms of body size Yellow-billed Oxpecker is territorial and capable of outcompeting the smaller Red-billed Oxpecker Hall-Martinpermitting the former a preferential choice of ungulates. The study also shows that Red-billed Oxpeckers in the southern regions of KNP utilised the preferred large ungulates in the absence of Yellow-billed Oxpeckers, whereas their preference shifted to smaller ungulates in the presence of Yellow-billed Oxpeckers.

This further supports the notion of interspecific competition between Red-billed and Yellow-billed Oxpeckers for access to larger ungulate hosts.

symbiotic relationship between oxpeckers and rhinoceroses evolution

Contrary to the results from the present study, Hustler and Koenig in Zimbabwe and Kenya respectively did not find any differences in host ungulate preferences when both species occurred within the same geographic region. Furthermore, Koenig did not find any marked differences in the host species preferences of Red-billed Oxpeckers when comparing between areas of sympatry and areas of allopatry. Perhaps these differences between the Kenya study and the KNP findings could be attributed to differences in ungulate densities between the two sites.

One would assume that the Kenya sites Masai Mara Reserve and Lake Nakuru National Park had a high abundance of large ungulates compared to KNP, hence a marked host preference would only be apparent in lower ungulate densities where interspecific competition is unavoidable.

However, that hypothesis cannot be tested without a measure of ungulate densities from all sites. Surprisingly, the PI results in the present study differed from Grobler and Stutterheim and Stutterheim Optimal foraging strategy Pyke will predict that animals will concentrate on the most abundant and profitable food source. For example, there were fewer White Rhinoceros and Hippopotamus in KNP in the s compared to the present-day population It is therefore reasonable to conclude that as White Rhinoceros and Hippopotamus numbers increased, Red-billed Oxpeckers responded by selecting for these new abundant host species with potentially higher tick loads and less hair to hide the ticks.

Red-billed oxpeckers: vampires or tickbirds? | Behavioral Ecology | Oxford Academic

Giraffe remained the most preferred host species in both the northern and southern regions of the park. This could also be a detection bias, given that it is possibly easier for flying birds to detect Giraffe compared to other shorter species.

This is further supported by Oxpeckers' preference for White Rhinoceros and Hippopotamus both large ungulatesrecorded as host species in Skukuza.

Interestingly, Impala, an abundant, small-sized ungulate, was less preferred as a host species across studies.

symbiotic relationship between oxpeckers and rhinoceroses evolution

This surprising contradicts what has been reported by GroblerStutterheim and Stutterheim and Hart et al. Both Red-billed and Yellow-billed Oxpeckers displayed a preference for the back and head regions of their respective host species. Red-billed Oxpeckers also preferred the necks of Giraffe.

Symbiotic Relationships: The Rhino & Oxpecker

Additionally, Oxpeckers prefer feeding on the back regions of a host species since this is easily accessible and provides a stable perch Weeks The head is also preferred since it provides additional food resources other than ticks, i.

Exceedingly low occurrences of wound feeding by Red-billed Oxpeckers and the absence of wound feeding in Yellow-billed Oxpeckers suggests that this feeding behaviour is not prevalent in KNP as previously reported in cattle ranches in Zimbabwe Weeks Plantanin her study on both Oxpecker species at Shingwedzi inalso found the prevalence of wound feeding behaviour to be very low 3. In addition, oxpeckers significantly prolonged the healing time of wounds and removed earwax. These results suggest that the oxpecker-mammal relationship is more complex than was previously thought.

symbiotic relationship between oxpeckers and rhinoceroses evolution

Red-billed oxpeckers Buphagus erythrorhynchus feed almost exclusively on what they can collect from the skin of large African mammals. Their diet includes ixodid ticks, dead skin, mucus, saliva, blood, sweat, and tears Bezuidenhout and Stutterheim, Ticks are costly parasites because they drain blood, inflict bites, and are vectors for many diseases Howell et al.

symbiotic relationship between oxpeckers and rhinoceroses evolution

It is thought that tick removal must be beneficial to the host mammals, and the relationship between oxpecker and mammal is therefore believed to be a mutualism Bezuidenhout and Stutterheim, ; Moreau, ; Mundy, ; Someren, Yet evidence for beneficial tick reduction is usually either anecdotal Pitman,or inferred Breitwisch, ; Someren, Mooring and Mundyfor instance, showed that the congeneric yellow-billed oxpeckers Buphagus africanus feed on those areas of an impala where the animal cannot groom itself head, neck, and earsand that these areas have significantly heavier tick loads than the rest of the body.

They went on to argue that this demonstrates the oxpecker's role in tick control. Yet their result indicates only that impalas are better at reducing their own tick loads than are oxpeckers, which they achieve by grooming themselves with their teeth, a behavior shown to be extremely effective at reducing tick loads Mooring et al.

They artificially infested two oxen with a known number of adult ticks of different species and put them in a pen with five red-billed oxpeckers.

symbiotic relationship between oxpeckers and rhinoceroses evolution

The birds significantly reduced the tick loads over a period of 7 days. While this demonstrated which tick species oxpeckers prefer to eat blue ticks, Boophilus decoloratus, and brown ear ticks, Rhipicephalus appendiculatusit did not show what effect oxpeckers might have in the field where ticks are attaching continuously to the host, oxpeckers will always have the option of other hosts to feed on, and where there is unlikely to be a ratio as high as five birds to two hosts 24 h a day.

Rhinos & the Oxpecker Bird

Although tick feeding has been the focus of much attention, the oxpecker's habit of feeding at open wounds has generally been ignored e. Some authors have even argued that this behavior may be beneficial to mammals because it keeps the wound clean and prevents both bacterial infection and infestation by Calliphoridae blow-flies Breitwisch, ; Someren, What is needed is an experiment similar to the ones carried out on cleaner fish Grutter, where the cleaner is excluded from a group of hosts and the effects compared to a control group.

If the birds do provide tick reduction benefits, then we should expect to see a significant increase in the numbers of ticks on the experimental animals. If blood is the favored food, however, then we might predict that the controls will have significantly more wounds than animals relieved of oxpecker attention. In this paper I present results from a field experiment designed to test the effects of excluding oxpeckers on their hosts. The work was carried out in the lowveld of southern Zimbabwe on red-billed oxpeckers and a small herd of domestic cattle.

Sentinel Ranch has a large population of red-billed oxpeckers that feed both on game and a study herd of 22 Bonsmara oxen the Bonsmara is a South African variety of cow, a cross between Bos taurus and Bos indicus. Up to 60 individual birds visited the kraal cattle enclosure every morning, where they would spend approximately 2 h feeding on the animals. Small groups of oxpeckers continued to visit and feed on the oxen in the field throughout the day Weeks, Cattle are hosts to five species of ixodid tick at Sentinel blue ticks, brown ear ticks, bont ticks Amblyommma hebraeum, red-legged ticks Rhipicephalus evertsi, and bont-legged ticks Hyalomma marginatum.

Those Little Birds On The Backs Of Rhinos Actually Drink Blood

Ticks have three life stages larva, nymph, and adulteach of which requires a different individual host on which they attach and engorge with blood before dropping off and metamorphosing to the next stage. The exception is the one-host blue tick, which goes through its entire life cycle a process that takes roughly 4 weeks on a single host. Adult male ticks of all species spend up to a month attached to their host; adult females are attached for about 1 week. For the experiment, I arbitrarily divided the herd into 2 groups of 11 animals, experimentals and controls.

For the first treatment 21 November DecemberI excluded oxpeckers from the experimental group for 4 weeks. Because adult ticks are continuously attaching to the hosts and their drop-off rate is low, this period would have been sufficient to detect any effect oxpeckers might have had on tick loads.

An assistant stayed with the herd throughout the day oxpeckers do not feed during the night and chased off any oxpeckers that attempted to land on the oxen.

Feeding preferences of Oxpeckers in Kruger National Park, South Africa

I remained with the control group, which oxpeckers continued to visit and feed on as normal. The two groups fed in two separate grazing areas, which I alternated every 2 days. They spent the night in separate cattle kraals, which I alternated every week. Controlling for grazing areas was particularly important because the ranch has large populations of other potential tick hosts, notably impala Aepyceros melampuseland Taurotragus oryxkudu Tragelaphus strepsicerosand warthog Phacochoerus aethipicus.