Administrative Information
‫المعلومات االدارية‬
Project Title - ‫عنوان المشروع‬
“Is Ecological Specialization in Lebanese Tephritid-Thistle Associations a Dead End?”
‫تطورا ً في عالقة ذباب الفاكهة باألشواك اللبنانية؟‬
ُّ ‫ي أكثر‬
ّ ‫هل التخصص اإليكولوج‬
Principal Investigator - ‫الباحث الرئيسي‬
‫رقم الهاتف‬
‫العنوان االلكتروني‬
‫العنوان‬
Telephone
e-mail
Address
01-350000; kknio@aub.edu.lb Biology
Extension:
Department,
3886
Faculty of
Arts and
Sciences,
American
University
of Beirut,
Beirut,
Lebanon
‫الوظيفية‬
Post
Professor
‫المؤسسة‬
Institution
American
University
of Beirut
‫االسم‬
Name
Khouzama
Knio
Co-Workers - ‫الباحثون المشاركون‬
‫العنوان االلكتروني‬
e-mail
cs10@aub.edu.lb
2 years (1 December 2009 – 31 December 2012)
‫المؤسسة‬
Institution
American
University of
Beirut
‫االسم‬
Name
Colin Smith
: Duration -‫المدة التعاقدية للمشروع‬
Scientific Information
‫العلمية‬
‫المعلومات‬
ّ
Objectives - ‫الهدف‬
The objectives of this project is to: 1) collect and rear fruit flies from different species of
Lebanese thistles (Asteraceae: Carduae) and identify new fruit fly-thistle associations; 2)
determine the phylogeny of the non-frugivorous tephritids associated with thistles in Lebanon;
3) determine whether specialist tephritids evolved from generalist species.
Achievements -‫أالنجازات المحققة‬
Fifty one fruit fly-thistle associations were collected during the duration of the project, of which
15 associations are new to Lebanon. All the associations new to Lebanon will be published in a
manuscript currently in preparation.
The method for extracting DNA from flies, amplifying three mitochondrial genes using PCR,
and sequencing the amplified genes was optimized. At least two flies representing each
collected association were sequenced.
A preliminary phylogenetic tree for all the collected associations was generated. As some
associations previously reported in the literature were not collected yet (The thistles were
collected but no flies emerged.), the phylogeny will be completed upon future collection
seasons. The evolution of specialization will be tested when a comprehensive phylogeny is
generated.
A major problem encountered during the study was that the weather in 2010 and more so in
2011 was rather unpredictable. Many of the thistles we were interested in collecting bloomed
earlier than expected and their flowering period lasted shorter than usual. This shift in
flowering phenology of the host thistles yielded a shift in emergence time of many of the fruit
flies we were interested in collecting. We consequently missed the chance of collecting several
fly-thistle associations.
Two achievements are worth noting:
1. We have previously published on host race formation in the generalist Chaetostomella
cylindrica (Partially funded by LNCSR; Colin Smith, PI). In this study, we sequenced flies
emerging from almost all plant hosts of this species. We have previously focused on two
common hosts. The results of this study confirm our previous hypothesis that the Onopordum
associated flies are distinct from the rest of the host populations, suggesting they might be a
distinct cryptic species. These results will be published in a separate paper.
2. We analyzed all host associations of two other generalists, Terellia serratulae and
Acanthiophilus helianthi.
a. In the case of T. serratulae, one host seems to be very distinct from the other host races. The
paper has been recently submitted and is under review. However, the relationship among the
other host races needs further investigation.
b. As for A. helianthi, our preliminary results confirm that it behaves as a typical generalist. It
would however be difficult to understand host race formation in this species without further
ecological and genetic studies.
Perspectives - ‫آفاق البحث‬
In addition to finalizing the phylogeny of Lebanese flower head infesting tephritids, we plan to
address several research questions, which arose from this study:
1. Resouce utilization in Terellia serratulae: This is important to resolve the observed
intraspecific variations among the different populations.
2. Biology and ecology of the generalist tephritid Acanthiophilus helianthi: This is
important to explain the observed size variation among the collected specimens
associated with different hosts, but not genetically distinct.
Publications & Communications - ‫المنشورات والمساهمات في المؤتمرات‬
Knio, K., M. S. Al-Zein, N. Sayar, S. Haddad and C. Smith. 2010. Host race formation in
flower-head infesting tephritids in Lebanon. 14th Evolutionary Biology Meeting, University of
EGEE, Marseilles, France. 21-24 September, 2010.
Knio, K., M. S. Al-Zein, N. Sayar, S. Haddad and C. Smith. 2012. Flower-head infesting
tephritids in Lebanon: specialization and host race formation. University of Balamand. 17
January 2012
Haddad, S. G., Smith, C. S., Knio, K. M. 2012. Genetic and morphometric variation as
evidence for host race formation in Terellia serratulae (Diptera: Tephritidae). Manuscript
under review.
Abstract - ‫موجز عن نتائج البحث‬
During 2010-2012, 25 species of thistles were collected from various sites in Lebanon. Fifty
one fruit fly-thistle associations were found, 15 of which were recorded to occur for the first
time in Lebanon. Methods for extracting DNA from the collected flies, amplifying three
mitochondrial genes using PCR, and sequencing the amplified genes were developed and
optimized. These yielded a preliminary phylogenetic tree for all the collected associations. The
study revealed important finding on three generalist species of tephritids.
The polyphagous fruit fly, Terellia serratulae, which exploits hosts belonging to three genera of
thistles (Carduus, Cirsium, and Picnomon), revealed significant morphometric and genetic
variations among the different host populations. The most useful predictors in distinguishing
adults associated with the different host plants were wing width and head length, in addition to
ovipositor length for females. Mitochondrial DNA sequencing revealed genetic differentiation
among the different populations of T. serratulae with the Picnomon acarna- associated
population being most distinct. Sequencing a region of the mtND1 gene revealed 19 single
nucleotide polymorphisms (SNPs) and 9 haplotypes, whereas sequencing a region of the
mtCOXI gene revealed 24 SNPs and 7 haplotypes. Surprisingly, haplotype sequences of flies
emerging from P. acarna showed a sequence divergence of over 3% for both COXI and ND1
genes. Therefore, the Lebanese T. serratulae population associated with P. acarna most likely
constitutes a distinct host race.
Another generalist species, Chaetostomella cylindrica, showed genetic variations among the
different host associated populations. The Onopordum-associated population could be
distinguished genetically and morphometrically from the rest of the host associations. This
suggests that the Onopordum associated population might be a new cryptic species.
Preliminary results on a third generalist species, Acanthiophilus helianthi, revealed little genetic
divergence between the different host plant associations, and seems to behave as a true
generalist having many generations per year and high flexibility for host exploitation.
Future studies will focus on collecting more tephritids and finding new tephritid-thistle
associations and shedding more light on host formation in the Lebanese fruit flies.