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Courses:
Organisms (BIO 114), Human Anatomy Lab (BIO 290)
Research Interests: Desert ecology and behavioral ecology
1. Sexual selection/ Sexual dimorphism
Sexual dimorphism is often displayed as a difference in size, weight,
appearance, or some combination of traits. An interesting
question is if the degree and type of sexual dimorphism is an indicator
of a specific social system. Many bird species exhibit sexual
dimorphism and are therefore frequently used for such studies.
For the last 3 years, I have studied sexual dimorphism in American
Robins (Turdus migratorius).
I used digital images of museum specimens to analyze, quantify, and
identify the presence and extent of color variation between the
sexes. I also banded animals for observational purposes. My
analyses of more than 200 museum specimens revealed a significant
difference in coloration between the sexes in adults and juveniles, as
well as between seasons in male animals.
Social mating systems and the type of parental care are assumed to be a
predictor of the type and extent of sexual dimorphism in adult
animals. However, previous studies, as well as personal field
observations, have revealed that these assumptions do not hold true for
a number of species. These studies on sexual dimorphism in birds,
especially, have used many different methods to determine plumage
differences. The use of various methods may account for the
differences in results and conclusions. By using digital images,
I was able to standardize and quantity the analysis of color
differences, which allowed for more reliable and accurate statistical
testing. Using these same methods, I would like continue along my
current line of research by investigating the following:
(1) Sexual and seasonal dimorphism in other bird species with different
mating systems. Do social mating systems predict the type and
intensity of sexual and seasonal dimorphism?
(2) The extent of sexual dimorphism in juvenile animals. I would
like analyze the plumage of juveniles of various bird species to
determine what type of correlation exists between sexual dimorphism in
juvenile animals and the social mating system of the species. In
particular, I am interested in why some species display sex differences
while in a non-reproducing phase.
(3) The correlation between sexual dimorphism and sex-based behavior
differences. In my current research I marked and observed
dragonflies (Eastern pondhawks, Erythemis
simplicicollis). I observed their foraging behavior in
fields, where the all green females blend into the green background,
while the mature, blue males stand out. I also observed
differences in predator escaping strategies.
2. Using Owl Pellets as indicators for animal diversity and
conservation strategies
Some studies have used owl pellets to determine animal diversity in a
particular area. I am however, interested in finding out what
differences exist between biodiversity indices generated from
traditional surveys versus biodiversity as measured from owl pellet
analyses. If owl pellets are just as good indicators, this method
could be a quick and inexpensive method for baseline surveys. I
would like to study the contents of owl pellets, to provide a more
standard method for comparing biodiversity measures using pellet
analyses versus traditional survey methods.
3. Using lizard communities in deserts as indicators for
desertification
Climate change has a huge impact on many ecosystems. One of the
ecosystems that haven’t been studies well in respect to climate change,
are desert ecosystems. I am currently working on finding funding for a
proposal on how lizard communities in desert ecosystems can be used as
indicators for the degree of disturbance in such systems.
Selected
Publications:
Disi, A. M., Modry, D., Necas, P. and Rifai, L.
2001. Amphibians and Reptiles of the Hashemite Kingdom of Jordan
- An Atlas and Field Guide. Chimaira, Frankfurt. 408pp.
Rifai, L. and Amr, Z. S. 2006. Diet of
the Stripe-Necked Terrapin, Mauremys
rivulata, in Jordan. Russian Journal of Herpetology, 13 (1).
Rifai, L. and Mantziou, G. 2005.
L’Emyde caspienne de l’ouest, Mauremys
rivulata,. MANOURIA 8 (29):33-36.
Rifai, L., Abu Baker, M., Al Shafei, D., Disi, A.
& Amr, Z. 2005. Pseudopus
apodus (Pallas, 1775) from Jordan, with notes on its ecology
(Sqamata: Sauria: Anguidae). Herpetozoa, 18(3/4): 133-140.
Maraqa, A., Amr, Z. Rifai, L. and Al-Melhim,
W. 2005. An Abattoir Survey of Liver and Lung Helminthic
Infections in Local and Imported Sheep in Jordan. Turkish Journal
of Veterinary and Animal Sciences, 29(1):1-2.
Rifai, L. B. and Amr, Z. S. 2004.
Morphometrics and biology of the Stripe-necked Terrapin, Mauremys rivulata (Valenciennes,
1833), in Jordan (Reptilia: Testudines: Geoemydidae). Zoologische
Abhandlungen (Dresden) 54:177-197.
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