Hastings Natural History Reservation

20 Mar, 04 AM - 21 Mar, 09 AM

Host-parasite systems are a powerful arena for evolutionary research because the environment of many parasites is defined almost exclusively by its host. In this way, factors governing evolution are easier to delineate for parasites than for free-living organisms. This is particularly true for parasites, which complete their entire life cycle on the body of a single host. In some cases the phylogeny of these parasites is congruent with that of the host, indicating cospeciation between host and parasite (Clayton, et al. 1992). Cospeciating host-parasite systems are unique in that they represent a long history of parallel evolution. This is important because it provides a temporal framework for comparative analyses of the rates of evolution of the host and parasite. Because the life histories of hosts and their parasites are generally extremely different, studying the molecular evolution in a host-parasite system can provide insight into questions relating to their possible effects of generation time, metabolic rate, and other life history parameters on rates of mutation and evolutionary change (Hafner, et al. 1994). In this study, we are looking at the coevolution between birds and their parasitic mites. Three main groups of mites are commonly found on birds: feather mites, quill mites, and nasal mites. The three mite types occupy very different habitats on their host. Nasal mites are found in the nares and turbinates of the upper beak, quill mites live inside the quill of the feathers, and feather mites are ectoparasitic scavengers on the feathers of birds. Avian mites are extremely widespread and are known to occur on every avian order, except Sphenisciformes (penguins) and Casuariiformes (cassowaries and emus). Avian mites generally complete their life-cycle on a single host, and host-to-host transfer normally occurs in the nest from parent to offspring (Atyeo and Gaud 1979). Because of these life history strategies it is very probable that feather mites have coevolved with their hosts. It has also been noted that two and sometimes three closely related mite species can be found on the same bird (Atyeo and Gaud 1979). This might indicate that the parasite exhibits a faster rate of speciation than does the host. This work should help in understanding the relationship between parasitic mites and their avian hosts. Although this study will not directly address the issues of disease, it should be helpful for future researchers who wish to study these parasites to examine their potential disease transmission among birds. The study will involve collection, identification, sequencing, and analysis of the sequences, for birds and their acarine parasites. Birds from different families within the order Piciformes and Passeriformes will be collected with a gun. After collection, the birds will be inspected for mites which will be removed and kept frozen. A voucher specimen will be set aside for each mite species which will be mounted for identification under a light microscope Spicer (1977, 1978, 1979, 1984). The remainder of the mites will be crushed and digested with lysis buffer for DNA extraction. DNA will be extracted from the pectoral muscle of each of the bird species using a Phenol/chloroform extraction protocol. The 16s rRNA gene and the nuclear large subunit rRNA gene will then be sequenced for both the birds and the mites. These sequences will be aligned using Sequencher 3.0 and analyzed using PAUP. Once the best tree(s) for the birds and for the mites is determined these trees will be compared in a program such as TreeMap to determine the extent of cospeciation between these two groups. Both the extent of mite-bird coevolution and the relative rates of speciation will be tested through molecular phylogenetics in this study. So far we have collected about eight different species of nasal mites that we have been able to successfully sequence. This shows that our techniques appear to be adequate for this study. Our initial studies indicate that cospeciation seems to be common in the nasal mite family Rhinonyssidae, but we need more species of mites and more sequence from each species to confirm these results.

Visit #6849 @Hastings Natural History Reservation

Approved

Under Project # 5141 | Research

Cospeciation between nasal mites and their bird hosts

faculty - San Francisco State University (CSU)

Reservation Members(s)

Group of 2 Graduate Student Mar 20 - 21, 2005 (2 days)
Greg Spicer Mar 20 - 21, 2005 (2 days)

Reserve Resources(s) | Create Invoice

Bunk House Cottage 3 Mar 20 - 21, 2005